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5356d32e 1/* sv.c
79072805 2 *
1129b882 3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
83706693
RGS
4 * 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 by Larry Wall
5 * and others
79072805
LW
6 *
7 * You may distribute under the terms of either the GNU General Public
8 * License or the Artistic License, as specified in the README file.
9 *
4ac71550
TC
10 */
11
12/*
13 * 'I wonder what the Entish is for "yes" and "no",' he thought.
14 * --Pippin
15 *
16 * [p.480 of _The Lord of the Rings_, III/iv: "Treebeard"]
17 */
18
19/*
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20 *
21 *
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AMS
22 * This file contains the code that creates, manipulates and destroys
23 * scalar values (SVs). The other types (AV, HV, GV, etc.) reuse the
24 * structure of an SV, so their creation and destruction is handled
25 * here; higher-level functions are in av.c, hv.c, and so on. Opcode
26 * level functions (eg. substr, split, join) for each of the types are
27 * in the pp*.c files.
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LW
28 */
29
30#include "EXTERN.h"
864dbfa3 31#define PERL_IN_SV_C
79072805 32#include "perl.h"
d2f185dc 33#include "regcomp.h"
9d9a81f0
CB
34#ifdef __VMS
35# include <rms.h>
36#endif
79072805 37
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OS
38#ifdef __Lynx__
39/* Missing proto on LynxOS */
40 char *gconvert(double, int, int, char *);
41#endif
42
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43#ifdef USE_QUADMATH
44# define SNPRINTF_G(nv, buffer, size, ndig) \
45 quadmath_snprintf(buffer, size, "%.*Qg", (int)ndig, (NV)(nv))
46#else
47# define SNPRINTF_G(nv, buffer, size, ndig) \
48 PERL_UNUSED_RESULT(Gconvert((NV)(nv), (int)ndig, 0, buffer))
49#endif
50
9f53080a 51#ifndef SV_COW_THRESHOLD
e8c6a474 52# define SV_COW_THRESHOLD 0 /* COW iff len > K */
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53#endif
54#ifndef SV_COWBUF_THRESHOLD
e8c6a474 55# define SV_COWBUF_THRESHOLD 1250 /* COW iff len > K */
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56#endif
57#ifndef SV_COW_MAX_WASTE_THRESHOLD
e8c6a474 58# define SV_COW_MAX_WASTE_THRESHOLD 80 /* COW iff (len - cur) < K */
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59#endif
60#ifndef SV_COWBUF_WASTE_THRESHOLD
e8c6a474 61# define SV_COWBUF_WASTE_THRESHOLD 80 /* COW iff (len - cur) < K */
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FC
62#endif
63#ifndef SV_COW_MAX_WASTE_FACTOR_THRESHOLD
e8c6a474 64# define SV_COW_MAX_WASTE_FACTOR_THRESHOLD 2 /* COW iff len < (cur * K) */
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65#endif
66#ifndef SV_COWBUF_WASTE_FACTOR_THRESHOLD
e8c6a474 67# define SV_COWBUF_WASTE_FACTOR_THRESHOLD 2 /* COW iff len < (cur * K) */
e8c6a474
YO
68#endif
69/* Work around compiler warnings about unsigned >= THRESHOLD when thres-
70 hold is 0. */
71#if SV_COW_THRESHOLD
72# define GE_COW_THRESHOLD(cur) ((cur) >= SV_COW_THRESHOLD)
73#else
74# define GE_COW_THRESHOLD(cur) 1
75#endif
76#if SV_COWBUF_THRESHOLD
77# define GE_COWBUF_THRESHOLD(cur) ((cur) >= SV_COWBUF_THRESHOLD)
78#else
79# define GE_COWBUF_THRESHOLD(cur) 1
80#endif
81#if SV_COW_MAX_WASTE_THRESHOLD
82# define GE_COW_MAX_WASTE_THRESHOLD(cur,len) (((len)-(cur)) < SV_COW_MAX_WASTE_THRESHOLD)
83#else
84# define GE_COW_MAX_WASTE_THRESHOLD(cur,len) 1
85#endif
86#if SV_COWBUF_WASTE_THRESHOLD
87# define GE_COWBUF_WASTE_THRESHOLD(cur,len) (((len)-(cur)) < SV_COWBUF_WASTE_THRESHOLD)
88#else
89# define GE_COWBUF_WASTE_THRESHOLD(cur,len) 1
90#endif
91#if SV_COW_MAX_WASTE_FACTOR_THRESHOLD
92# define GE_COW_MAX_WASTE_FACTOR_THRESHOLD(cur,len) ((len) < SV_COW_MAX_WASTE_FACTOR_THRESHOLD * (cur))
93#else
94# define GE_COW_MAX_WASTE_FACTOR_THRESHOLD(cur,len) 1
95#endif
96#if SV_COWBUF_WASTE_FACTOR_THRESHOLD
97# define GE_COWBUF_WASTE_FACTOR_THRESHOLD(cur,len) ((len) < SV_COWBUF_WASTE_FACTOR_THRESHOLD * (cur))
98#else
99# define GE_COWBUF_WASTE_FACTOR_THRESHOLD(cur,len) 1
100#endif
101
102#define CHECK_COW_THRESHOLD(cur,len) (\
103 GE_COW_THRESHOLD((cur)) && \
104 GE_COW_MAX_WASTE_THRESHOLD((cur),(len)) && \
105 GE_COW_MAX_WASTE_FACTOR_THRESHOLD((cur),(len)) \
106)
107#define CHECK_COWBUF_THRESHOLD(cur,len) (\
108 GE_COWBUF_THRESHOLD((cur)) && \
109 GE_COWBUF_WASTE_THRESHOLD((cur),(len)) && \
110 GE_COWBUF_WASTE_FACTOR_THRESHOLD((cur),(len)) \
111)
cca0492e 112
e23c8137 113#ifdef PERL_UTF8_CACHE_ASSERT
ab455f60 114/* if adding more checks watch out for the following tests:
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115 * t/op/index.t t/op/length.t t/op/pat.t t/op/substr.t
116 * lib/utf8.t lib/Unicode/Collate/t/index.t
117 * --jhi
118 */
6f207bd3 119# define ASSERT_UTF8_CACHE(cache) \
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120 STMT_START { if (cache) { assert((cache)[0] <= (cache)[1]); \
121 assert((cache)[2] <= (cache)[3]); \
122 assert((cache)[3] <= (cache)[1]);} \
123 } STMT_END
e23c8137 124#else
6f207bd3 125# define ASSERT_UTF8_CACHE(cache) NOOP
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126#endif
127
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128static const char S_destroy[] = "DESTROY";
129#define S_destroy_len (sizeof(S_destroy)-1)
130
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131/* ============================================================================
132
133=head1 Allocation and deallocation of SVs.
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134An SV (or AV, HV, etc.) is allocated in two parts: the head (struct
135sv, av, hv...) contains type and reference count information, and for
136many types, a pointer to the body (struct xrv, xpv, xpviv...), which
137contains fields specific to each type. Some types store all they need
138in the head, so don't have a body.
139
486ec47a 140In all but the most memory-paranoid configurations (ex: PURIFY), heads
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141and bodies are allocated out of arenas, which by default are
142approximately 4K chunks of memory parcelled up into N heads or bodies.
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143Sv-bodies are allocated by their sv-type, guaranteeing size
144consistency needed to allocate safely from arrays.
145
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146For SV-heads, the first slot in each arena is reserved, and holds a
147link to the next arena, some flags, and a note of the number of slots.
148Snaked through each arena chain is a linked list of free items; when
149this becomes empty, an extra arena is allocated and divided up into N
150items which are threaded into the free list.
151
152SV-bodies are similar, but they use arena-sets by default, which
153separate the link and info from the arena itself, and reclaim the 1st
154slot in the arena. SV-bodies are further described later.
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155
156The following global variables are associated with arenas:
157
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158 PL_sv_arenaroot pointer to list of SV arenas
159 PL_sv_root pointer to list of free SV structures
645c22ef 160
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161 PL_body_arenas head of linked-list of body arenas
162 PL_body_roots[] array of pointers to list of free bodies of svtype
163 arrays are indexed by the svtype needed
93e68bfb 164
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165A few special SV heads are not allocated from an arena, but are
166instead directly created in the interpreter structure, eg PL_sv_undef.
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167The size of arenas can be changed from the default by setting
168PERL_ARENA_SIZE appropriately at compile time.
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169
170The SV arena serves the secondary purpose of allowing still-live SVs
171to be located and destroyed during final cleanup.
172
173At the lowest level, the macros new_SV() and del_SV() grab and free
174an SV head. (If debugging with -DD, del_SV() calls the function S_del_sv()
175to return the SV to the free list with error checking.) new_SV() calls
176more_sv() / sv_add_arena() to add an extra arena if the free list is empty.
177SVs in the free list have their SvTYPE field set to all ones.
178
ff276b08 179At the time of very final cleanup, sv_free_arenas() is called from
645c22ef 180perl_destruct() to physically free all the arenas allocated since the
6a93a7e5 181start of the interpreter.
645c22ef 182
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183The function visit() scans the SV arenas list, and calls a specified
184function for each SV it finds which is still live - ie which has an SvTYPE
185other than all 1's, and a non-zero SvREFCNT. visit() is used by the
186following functions (specified as [function that calls visit()] / [function
187called by visit() for each SV]):
188
189 sv_report_used() / do_report_used()
f2524eef 190 dump all remaining SVs (debugging aid)
645c22ef 191
e4487e9b 192 sv_clean_objs() / do_clean_objs(),do_clean_named_objs(),
e76981f9 193 do_clean_named_io_objs(),do_curse()
645c22ef 194 Attempt to free all objects pointed to by RVs,
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195 try to do the same for all objects indir-
196 ectly referenced by typeglobs too, and
197 then do a final sweep, cursing any
198 objects that remain. Called once from
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199 perl_destruct(), prior to calling sv_clean_all()
200 below.
201
202 sv_clean_all() / do_clean_all()
203 SvREFCNT_dec(sv) each remaining SV, possibly
204 triggering an sv_free(). It also sets the
205 SVf_BREAK flag on the SV to indicate that the
206 refcnt has been artificially lowered, and thus
207 stopping sv_free() from giving spurious warnings
208 about SVs which unexpectedly have a refcnt
209 of zero. called repeatedly from perl_destruct()
210 until there are no SVs left.
211
93e68bfb 212=head2 Arena allocator API Summary
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213
214Private API to rest of sv.c
215
216 new_SV(), del_SV(),
217
df0f0429 218 new_XPVNV(), del_XPVGV(),
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219 etc
220
221Public API:
222
8cf8f3d1 223 sv_report_used(), sv_clean_objs(), sv_clean_all(), sv_free_arenas()
645c22ef 224
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225=cut
226
3e8320cc 227 * ========================================================================= */
645c22ef 228
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229/*
230 * "A time to plant, and a time to uproot what was planted..."
231 */
232
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233#ifdef PERL_MEM_LOG
234# define MEM_LOG_NEW_SV(sv, file, line, func) \
235 Perl_mem_log_new_sv(sv, file, line, func)
236# define MEM_LOG_DEL_SV(sv, file, line, func) \
237 Perl_mem_log_del_sv(sv, file, line, func)
238#else
239# define MEM_LOG_NEW_SV(sv, file, line, func) NOOP
240# define MEM_LOG_DEL_SV(sv, file, line, func) NOOP
241#endif
242
fd0854ff 243#ifdef DEBUG_LEAKING_SCALARS
484e6108
FC
244# define FREE_SV_DEBUG_FILE(sv) STMT_START { \
245 if ((sv)->sv_debug_file) PerlMemShared_free((sv)->sv_debug_file); \
246 } STMT_END
d7a2c63c 247# define DEBUG_SV_SERIAL(sv) \
147e3846 248 DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf ": (%05ld) del_SV\n", \
d7a2c63c 249 PTR2UV(sv), (long)(sv)->sv_debug_serial))
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250#else
251# define FREE_SV_DEBUG_FILE(sv)
d7a2c63c 252# define DEBUG_SV_SERIAL(sv) NOOP
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253#endif
254
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NC
255#ifdef PERL_POISON
256# define SvARENA_CHAIN(sv) ((sv)->sv_u.svu_rv)
daba3364 257# define SvARENA_CHAIN_SET(sv,val) (sv)->sv_u.svu_rv = MUTABLE_SV((val))
48614a46
NC
258/* Whilst I'd love to do this, it seems that things like to check on
259 unreferenced scalars
ce5dbf61 260# define POISON_SV_HEAD(sv) PoisonNew(sv, 1, struct STRUCT_SV)
48614a46 261*/
ce5dbf61 262# define POISON_SV_HEAD(sv) PoisonNew(&SvANY(sv), 1, void *), \
7e337ee0 263 PoisonNew(&SvREFCNT(sv), 1, U32)
48614a46
NC
264#else
265# define SvARENA_CHAIN(sv) SvANY(sv)
3eef1deb 266# define SvARENA_CHAIN_SET(sv,val) SvANY(sv) = (void *)(val)
ce5dbf61 267# define POISON_SV_HEAD(sv)
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NC
268#endif
269
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DM
270/* Mark an SV head as unused, and add to free list.
271 *
272 * If SVf_BREAK is set, skip adding it to the free list, as this SV had
273 * its refcount artificially decremented during global destruction, so
274 * there may be dangling pointers to it. The last thing we want in that
275 * case is for it to be reused. */
276
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277#define plant_SV(p) \
278 STMT_START { \
990198f0 279 const U32 old_flags = SvFLAGS(p); \
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280 MEM_LOG_DEL_SV(p, __FILE__, __LINE__, FUNCTION__); \
281 DEBUG_SV_SERIAL(p); \
fd0854ff 282 FREE_SV_DEBUG_FILE(p); \
ce5dbf61 283 POISON_SV_HEAD(p); \
053fc874 284 SvFLAGS(p) = SVTYPEMASK; \
990198f0 285 if (!(old_flags & SVf_BREAK)) { \
3eef1deb 286 SvARENA_CHAIN_SET(p, PL_sv_root); \
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287 PL_sv_root = (p); \
288 } \
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289 --PL_sv_count; \
290 } STMT_END
a0d0e21e 291
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292#define uproot_SV(p) \
293 STMT_START { \
294 (p) = PL_sv_root; \
daba3364 295 PL_sv_root = MUTABLE_SV(SvARENA_CHAIN(p)); \
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296 ++PL_sv_count; \
297 } STMT_END
298
645c22ef 299
cac9b346
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300/* make some more SVs by adding another arena */
301
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NC
302STATIC SV*
303S_more_sv(pTHX)
304{
305 SV* sv;
9a87bd09
NC
306 char *chunk; /* must use New here to match call to */
307 Newx(chunk,PERL_ARENA_SIZE,char); /* Safefree() in sv_free_arenas() */
308 sv_add_arena(chunk, PERL_ARENA_SIZE, 0);
cac9b346
NC
309 uproot_SV(sv);
310 return sv;
311}
312
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313/* new_SV(): return a new, empty SV head */
314
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315#ifdef DEBUG_LEAKING_SCALARS
316/* provide a real function for a debugger to play with */
317STATIC SV*
d7a2c63c 318S_new_SV(pTHX_ const char *file, int line, const char *func)
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DM
319{
320 SV* sv;
321
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DM
322 if (PL_sv_root)
323 uproot_SV(sv);
324 else
cac9b346 325 sv = S_more_sv(aTHX);
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326 SvANY(sv) = 0;
327 SvREFCNT(sv) = 1;
328 SvFLAGS(sv) = 0;
fd0854ff 329 sv->sv_debug_optype = PL_op ? PL_op->op_type : 0;
e385c3bf
DM
330 sv->sv_debug_line = (U16) (PL_parser && PL_parser->copline != NOLINE
331 ? PL_parser->copline
332 : PL_curcop
f24aceb1
DM
333 ? CopLINE(PL_curcop)
334 : 0
e385c3bf 335 );
fd0854ff 336 sv->sv_debug_inpad = 0;
cd676548 337 sv->sv_debug_parent = NULL;
484e6108 338 sv->sv_debug_file = PL_curcop ? savesharedpv(CopFILE(PL_curcop)): NULL;
d7a2c63c
MHM
339
340 sv->sv_debug_serial = PL_sv_serial++;
341
342 MEM_LOG_NEW_SV(sv, file, line, func);
147e3846 343 DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf ": (%05ld) new_SV (from %s:%d [%s])\n",
d7a2c63c
MHM
344 PTR2UV(sv), (long)sv->sv_debug_serial, file, line, func));
345
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346 return sv;
347}
d7a2c63c 348# define new_SV(p) (p)=S_new_SV(aTHX_ __FILE__, __LINE__, FUNCTION__)
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349
350#else
351# define new_SV(p) \
053fc874 352 STMT_START { \
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353 if (PL_sv_root) \
354 uproot_SV(p); \
355 else \
cac9b346 356 (p) = S_more_sv(aTHX); \
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357 SvANY(p) = 0; \
358 SvREFCNT(p) = 1; \
359 SvFLAGS(p) = 0; \
d7a2c63c 360 MEM_LOG_NEW_SV(p, __FILE__, __LINE__, FUNCTION__); \
053fc874 361 } STMT_END
eba0f806 362#endif
463ee0b2 363
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364
365/* del_SV(): return an empty SV head to the free list */
366
a0d0e21e 367#ifdef DEBUGGING
4561caa4 368
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369#define del_SV(p) \
370 STMT_START { \
aea4f609 371 if (DEBUG_D_TEST) \
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372 del_sv(p); \
373 else \
374 plant_SV(p); \
053fc874 375 } STMT_END
a0d0e21e 376
76e3520e 377STATIC void
cea2e8a9 378S_del_sv(pTHX_ SV *p)
463ee0b2 379{
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380 PERL_ARGS_ASSERT_DEL_SV;
381
aea4f609 382 if (DEBUG_D_TEST) {
4633a7c4 383 SV* sva;
a3b680e6 384 bool ok = 0;
daba3364 385 for (sva = PL_sv_arenaroot; sva; sva = MUTABLE_SV(SvANY(sva))) {
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AL
386 const SV * const sv = sva + 1;
387 const SV * const svend = &sva[SvREFCNT(sva)];
c0ff570e 388 if (p >= sv && p < svend) {
a0d0e21e 389 ok = 1;
c0ff570e
NC
390 break;
391 }
a0d0e21e
LW
392 }
393 if (!ok) {
9b387841 394 Perl_ck_warner_d(aTHX_ packWARN(WARN_INTERNAL),
147e3846 395 "Attempt to free non-arena SV: 0x%" UVxf
9b387841 396 pTHX__FORMAT, PTR2UV(p) pTHX__VALUE);
a0d0e21e
LW
397 return;
398 }
399 }
4561caa4 400 plant_SV(p);
463ee0b2 401}
a0d0e21e 402
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403#else /* ! DEBUGGING */
404
405#define del_SV(p) plant_SV(p)
406
407#endif /* DEBUGGING */
463ee0b2 408
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409
410/*
ccfc67b7
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411=head1 SV Manipulation Functions
412
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413=for apidoc sv_add_arena
414
415Given a chunk of memory, link it to the head of the list of arenas,
416and split it into a list of free SVs.
417
418=cut
419*/
420
d2bd4e7f
NC
421static void
422S_sv_add_arena(pTHX_ char *const ptr, const U32 size, const U32 flags)
463ee0b2 423{
daba3364 424 SV *const sva = MUTABLE_SV(ptr);
eb578fdb
KW
425 SV* sv;
426 SV* svend;
4633a7c4 427
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NC
428 PERL_ARGS_ASSERT_SV_ADD_ARENA;
429
4633a7c4 430 /* The first SV in an arena isn't an SV. */
3280af22 431 SvANY(sva) = (void *) PL_sv_arenaroot; /* ptr to next arena */
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LW
432 SvREFCNT(sva) = size / sizeof(SV); /* number of SV slots */
433 SvFLAGS(sva) = flags; /* FAKE if not to be freed */
434
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435 PL_sv_arenaroot = sva;
436 PL_sv_root = sva + 1;
4633a7c4
LW
437
438 svend = &sva[SvREFCNT(sva) - 1];
439 sv = sva + 1;
463ee0b2 440 while (sv < svend) {
3eef1deb 441 SvARENA_CHAIN_SET(sv, (sv + 1));
03e36789 442#ifdef DEBUGGING
978b032e 443 SvREFCNT(sv) = 0;
03e36789 444#endif
4b69cbe3 445 /* Must always set typemask because it's always checked in on cleanup
03e36789 446 when the arenas are walked looking for objects. */
8990e307 447 SvFLAGS(sv) = SVTYPEMASK;
463ee0b2
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448 sv++;
449 }
3eef1deb 450 SvARENA_CHAIN_SET(sv, 0);
03e36789
NC
451#ifdef DEBUGGING
452 SvREFCNT(sv) = 0;
453#endif
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LW
454 SvFLAGS(sv) = SVTYPEMASK;
455}
456
055972dc
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457/* visit(): call the named function for each non-free SV in the arenas
458 * whose flags field matches the flags/mask args. */
645c22ef 459
5226ed68 460STATIC I32
de37a194 461S_visit(pTHX_ SVFUNC_t f, const U32 flags, const U32 mask)
8990e307 462{
4633a7c4 463 SV* sva;
5226ed68 464 I32 visited = 0;
8990e307 465
7918f24d
NC
466 PERL_ARGS_ASSERT_VISIT;
467
daba3364 468 for (sva = PL_sv_arenaroot; sva; sva = MUTABLE_SV(SvANY(sva))) {
eb578fdb
KW
469 const SV * const svend = &sva[SvREFCNT(sva)];
470 SV* sv;
4561caa4 471 for (sv = sva + 1; sv < svend; ++sv) {
e4787c0c 472 if (SvTYPE(sv) != (svtype)SVTYPEMASK
055972dc
DM
473 && (sv->sv_flags & mask) == flags
474 && SvREFCNT(sv))
475 {
942481a7 476 (*f)(aTHX_ sv);
5226ed68
JH
477 ++visited;
478 }
8990e307
LW
479 }
480 }
5226ed68 481 return visited;
8990e307
LW
482}
483
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JH
484#ifdef DEBUGGING
485
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486/* called by sv_report_used() for each live SV */
487
488static void
5fa45a31 489do_report_used(pTHX_ SV *const sv)
645c22ef 490{
e4787c0c 491 if (SvTYPE(sv) != (svtype)SVTYPEMASK) {
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DM
492 PerlIO_printf(Perl_debug_log, "****\n");
493 sv_dump(sv);
494 }
495}
758a08c3 496#endif
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497
498/*
499=for apidoc sv_report_used
500
fde67290 501Dump the contents of all SVs not yet freed (debugging aid).
645c22ef
DM
502
503=cut
504*/
505
8990e307 506void
864dbfa3 507Perl_sv_report_used(pTHX)
4561caa4 508{
ff270d3a 509#ifdef DEBUGGING
055972dc 510 visit(do_report_used, 0, 0);
96a5add6
AL
511#else
512 PERL_UNUSED_CONTEXT;
ff270d3a 513#endif
4561caa4
CS
514}
515
645c22ef
DM
516/* called by sv_clean_objs() for each live SV */
517
518static void
de37a194 519do_clean_objs(pTHX_ SV *const ref)
645c22ef 520{
ea724faa
NC
521 assert (SvROK(ref));
522 {
823a54a3
AL
523 SV * const target = SvRV(ref);
524 if (SvOBJECT(target)) {
525 DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning object ref:\n "), sv_dump(ref)));
526 if (SvWEAKREF(ref)) {
527 sv_del_backref(target, ref);
528 SvWEAKREF_off(ref);
529 SvRV_set(ref, NULL);
530 } else {
531 SvROK_off(ref);
532 SvRV_set(ref, NULL);
fc2b2dca 533 SvREFCNT_dec_NN(target);
823a54a3 534 }
645c22ef
DM
535 }
536 }
645c22ef
DM
537}
538
645c22ef 539
e4487e9b
DM
540/* clear any slots in a GV which hold objects - except IO;
541 * called by sv_clean_objs() for each live GV */
542
645c22ef 543static void
f30de749 544do_clean_named_objs(pTHX_ SV *const sv)
645c22ef 545{
57ef47cc 546 SV *obj;
ea724faa 547 assert(SvTYPE(sv) == SVt_PVGV);
d011219a 548 assert(isGV_with_GP(sv));
57ef47cc
DM
549 if (!GvGP(sv))
550 return;
551
552 /* freeing GP entries may indirectly free the current GV;
553 * hold onto it while we mess with the GP slots */
554 SvREFCNT_inc(sv);
555
556 if ( ((obj = GvSV(sv) )) && SvOBJECT(obj)) {
557 DEBUG_D((PerlIO_printf(Perl_debug_log,
558 "Cleaning named glob SV object:\n "), sv_dump(obj)));
559 GvSV(sv) = NULL;
fc2b2dca 560 SvREFCNT_dec_NN(obj);
57ef47cc
DM
561 }
562 if ( ((obj = MUTABLE_SV(GvAV(sv)) )) && SvOBJECT(obj)) {
563 DEBUG_D((PerlIO_printf(Perl_debug_log,
564 "Cleaning named glob AV object:\n "), sv_dump(obj)));
565 GvAV(sv) = NULL;
fc2b2dca 566 SvREFCNT_dec_NN(obj);
57ef47cc
DM
567 }
568 if ( ((obj = MUTABLE_SV(GvHV(sv)) )) && SvOBJECT(obj)) {
569 DEBUG_D((PerlIO_printf(Perl_debug_log,
570 "Cleaning named glob HV object:\n "), sv_dump(obj)));
571 GvHV(sv) = NULL;
fc2b2dca 572 SvREFCNT_dec_NN(obj);
57ef47cc
DM
573 }
574 if ( ((obj = MUTABLE_SV(GvCV(sv)) )) && SvOBJECT(obj)) {
575 DEBUG_D((PerlIO_printf(Perl_debug_log,
576 "Cleaning named glob CV object:\n "), sv_dump(obj)));
c43ae56f 577 GvCV_set(sv, NULL);
fc2b2dca 578 SvREFCNT_dec_NN(obj);
57ef47cc 579 }
fc2b2dca 580 SvREFCNT_dec_NN(sv); /* undo the inc above */
e4487e9b
DM
581}
582
68b590d9 583/* clear any IO slots in a GV which hold objects (except stderr, defout);
e4487e9b
DM
584 * called by sv_clean_objs() for each live GV */
585
586static void
587do_clean_named_io_objs(pTHX_ SV *const sv)
588{
e4487e9b
DM
589 SV *obj;
590 assert(SvTYPE(sv) == SVt_PVGV);
591 assert(isGV_with_GP(sv));
68b590d9 592 if (!GvGP(sv) || sv == (SV*)PL_stderrgv || sv == (SV*)PL_defoutgv)
e4487e9b
DM
593 return;
594
595 SvREFCNT_inc(sv);
57ef47cc
DM
596 if ( ((obj = MUTABLE_SV(GvIO(sv)) )) && SvOBJECT(obj)) {
597 DEBUG_D((PerlIO_printf(Perl_debug_log,
598 "Cleaning named glob IO object:\n "), sv_dump(obj)));
599 GvIOp(sv) = NULL;
fc2b2dca 600 SvREFCNT_dec_NN(obj);
645c22ef 601 }
fc2b2dca 602 SvREFCNT_dec_NN(sv); /* undo the inc above */
645c22ef 603}
645c22ef 604
4155e4fe
FC
605/* Void wrapper to pass to visit() */
606static void
607do_curse(pTHX_ SV * const sv) {
c2910e6c
FC
608 if ((PL_stderrgv && GvGP(PL_stderrgv) && (SV*)GvIO(PL_stderrgv) == sv)
609 || (PL_defoutgv && GvGP(PL_defoutgv) && (SV*)GvIO(PL_defoutgv) == sv))
4155e4fe
FC
610 return;
611 (void)curse(sv, 0);
612}
613
645c22ef
DM
614/*
615=for apidoc sv_clean_objs
616
fde67290 617Attempt to destroy all objects not yet freed.
645c22ef
DM
618
619=cut
620*/
621
4561caa4 622void
864dbfa3 623Perl_sv_clean_objs(pTHX)
4561caa4 624{
68b590d9 625 GV *olddef, *olderr;
3280af22 626 PL_in_clean_objs = TRUE;
055972dc 627 visit(do_clean_objs, SVf_ROK, SVf_ROK);
e4487e9b
DM
628 /* Some barnacles may yet remain, clinging to typeglobs.
629 * Run the non-IO destructors first: they may want to output
630 * error messages, close files etc */
d011219a 631 visit(do_clean_named_objs, SVt_PVGV|SVpgv_GP, SVTYPEMASK|SVp_POK|SVpgv_GP);
e4487e9b 632 visit(do_clean_named_io_objs, SVt_PVGV|SVpgv_GP, SVTYPEMASK|SVp_POK|SVpgv_GP);
4155e4fe
FC
633 /* And if there are some very tenacious barnacles clinging to arrays,
634 closures, or what have you.... */
635 visit(do_curse, SVs_OBJECT, SVs_OBJECT);
68b590d9
DM
636 olddef = PL_defoutgv;
637 PL_defoutgv = NULL; /* disable skip of PL_defoutgv */
638 if (olddef && isGV_with_GP(olddef))
639 do_clean_named_io_objs(aTHX_ MUTABLE_SV(olddef));
640 olderr = PL_stderrgv;
641 PL_stderrgv = NULL; /* disable skip of PL_stderrgv */
642 if (olderr && isGV_with_GP(olderr))
643 do_clean_named_io_objs(aTHX_ MUTABLE_SV(olderr));
644 SvREFCNT_dec(olddef);
3280af22 645 PL_in_clean_objs = FALSE;
4561caa4
CS
646}
647
645c22ef
DM
648/* called by sv_clean_all() for each live SV */
649
650static void
de37a194 651do_clean_all(pTHX_ SV *const sv)
645c22ef 652{
daba3364 653 if (sv == (const SV *) PL_fdpid || sv == (const SV *)PL_strtab) {
cddfcddc 654 /* don't clean pid table and strtab */
d17ea597 655 return;
cddfcddc 656 }
147e3846 657 DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning loops: SV at 0x%" UVxf "\n", PTR2UV(sv)) ));
645c22ef 658 SvFLAGS(sv) |= SVf_BREAK;
fc2b2dca 659 SvREFCNT_dec_NN(sv);
645c22ef
DM
660}
661
662/*
663=for apidoc sv_clean_all
664
665Decrement the refcnt of each remaining SV, possibly triggering a
fde67290 666cleanup. This function may have to be called multiple times to free
ff276b08 667SVs which are in complex self-referential hierarchies.
645c22ef
DM
668
669=cut
670*/
671
5226ed68 672I32
864dbfa3 673Perl_sv_clean_all(pTHX)
8990e307 674{
5226ed68 675 I32 cleaned;
3280af22 676 PL_in_clean_all = TRUE;
055972dc 677 cleaned = visit(do_clean_all, 0,0);
5226ed68 678 return cleaned;
8990e307 679}
463ee0b2 680
5e258f8c
JC
681/*
682 ARENASETS: a meta-arena implementation which separates arena-info
683 into struct arena_set, which contains an array of struct
684 arena_descs, each holding info for a single arena. By separating
685 the meta-info from the arena, we recover the 1st slot, formerly
686 borrowed for list management. The arena_set is about the size of an
39244528 687 arena, avoiding the needless malloc overhead of a naive linked-list.
5e258f8c
JC
688
689 The cost is 1 arena-set malloc per ~320 arena-mallocs, + the unused
690 memory in the last arena-set (1/2 on average). In trade, we get
691 back the 1st slot in each arena (ie 1.7% of a CV-arena, less for
d2a0f284 692 smaller types). The recovery of the wasted space allows use of
e15dad31
JC
693 small arenas for large, rare body types, by changing array* fields
694 in body_details_by_type[] below.
5e258f8c 695*/
5e258f8c 696struct arena_desc {
398c677b
NC
697 char *arena; /* the raw storage, allocated aligned */
698 size_t size; /* its size ~4k typ */
e5973ed5 699 svtype utype; /* bodytype stored in arena */
5e258f8c
JC
700};
701
e6148039
NC
702struct arena_set;
703
704/* Get the maximum number of elements in set[] such that struct arena_set
e15dad31 705 will fit within PERL_ARENA_SIZE, which is probably just under 4K, and
e6148039
NC
706 therefore likely to be 1 aligned memory page. */
707
708#define ARENAS_PER_SET ((PERL_ARENA_SIZE - sizeof(struct arena_set*) \
709 - 2 * sizeof(int)) / sizeof (struct arena_desc))
5e258f8c
JC
710
711struct arena_set {
712 struct arena_set* next;
0a848332
NC
713 unsigned int set_size; /* ie ARENAS_PER_SET */
714 unsigned int curr; /* index of next available arena-desc */
5e258f8c
JC
715 struct arena_desc set[ARENAS_PER_SET];
716};
717
645c22ef
DM
718/*
719=for apidoc sv_free_arenas
720
fde67290 721Deallocate the memory used by all arenas. Note that all the individual SV
645c22ef
DM
722heads and bodies within the arenas must already have been freed.
723
724=cut
7fefc6c1 725
645c22ef 726*/
4633a7c4 727void
864dbfa3 728Perl_sv_free_arenas(pTHX)
4633a7c4
LW
729{
730 SV* sva;
731 SV* svanext;
0a848332 732 unsigned int i;
4633a7c4
LW
733
734 /* Free arenas here, but be careful about fake ones. (We assume
735 contiguity of the fake ones with the corresponding real ones.) */
736
3280af22 737 for (sva = PL_sv_arenaroot; sva; sva = svanext) {
daba3364 738 svanext = MUTABLE_SV(SvANY(sva));
4633a7c4 739 while (svanext && SvFAKE(svanext))
daba3364 740 svanext = MUTABLE_SV(SvANY(svanext));
4633a7c4
LW
741
742 if (!SvFAKE(sva))
1df70142 743 Safefree(sva);
4633a7c4 744 }
93e68bfb 745
5e258f8c 746 {
0a848332
NC
747 struct arena_set *aroot = (struct arena_set*) PL_body_arenas;
748
749 while (aroot) {
750 struct arena_set *current = aroot;
751 i = aroot->curr;
752 while (i--) {
5e258f8c
JC
753 assert(aroot->set[i].arena);
754 Safefree(aroot->set[i].arena);
755 }
0a848332
NC
756 aroot = aroot->next;
757 Safefree(current);
5e258f8c
JC
758 }
759 }
dc8220bf 760 PL_body_arenas = 0;
fdda85ca 761
0a848332
NC
762 i = PERL_ARENA_ROOTS_SIZE;
763 while (i--)
93e68bfb 764 PL_body_roots[i] = 0;
93e68bfb 765
3280af22
NIS
766 PL_sv_arenaroot = 0;
767 PL_sv_root = 0;
4633a7c4
LW
768}
769
bd81e77b
NC
770/*
771 Here are mid-level routines that manage the allocation of bodies out
772 of the various arenas. There are 5 kinds of arenas:
29489e7c 773
bd81e77b
NC
774 1. SV-head arenas, which are discussed and handled above
775 2. regular body arenas
776 3. arenas for reduced-size bodies
777 4. Hash-Entry arenas
29489e7c 778
bd81e77b
NC
779 Arena types 2 & 3 are chained by body-type off an array of
780 arena-root pointers, which is indexed by svtype. Some of the
781 larger/less used body types are malloced singly, since a large
782 unused block of them is wasteful. Also, several svtypes dont have
783 bodies; the data fits into the sv-head itself. The arena-root
784 pointer thus has a few unused root-pointers (which may be hijacked
785 later for arena types 4,5)
29489e7c 786
bd81e77b
NC
787 3 differs from 2 as an optimization; some body types have several
788 unused fields in the front of the structure (which are kept in-place
789 for consistency). These bodies can be allocated in smaller chunks,
790 because the leading fields arent accessed. Pointers to such bodies
791 are decremented to point at the unused 'ghost' memory, knowing that
792 the pointers are used with offsets to the real memory.
29489e7c 793
d2a0f284
JC
794
795=head1 SV-Body Allocation
796
f554dfc5
MH
797=cut
798
d2a0f284
JC
799Allocation of SV-bodies is similar to SV-heads, differing as follows;
800the allocation mechanism is used for many body types, so is somewhat
801more complicated, it uses arena-sets, and has no need for still-live
802SV detection.
803
804At the outermost level, (new|del)_X*V macros return bodies of the
805appropriate type. These macros call either (new|del)_body_type or
806(new|del)_body_allocated macro pairs, depending on specifics of the
807type. Most body types use the former pair, the latter pair is used to
808allocate body types with "ghost fields".
809
810"ghost fields" are fields that are unused in certain types, and
69ba284b 811consequently don't need to actually exist. They are declared because
d2a0f284
JC
812they're part of a "base type", which allows use of functions as
813methods. The simplest examples are AVs and HVs, 2 aggregate types
814which don't use the fields which support SCALAR semantics.
815
69ba284b 816For these types, the arenas are carved up into appropriately sized
d2a0f284
JC
817chunks, we thus avoid wasted memory for those unaccessed members.
818When bodies are allocated, we adjust the pointer back in memory by the
69ba284b 819size of the part not allocated, so it's as if we allocated the full
d2a0f284
JC
820structure. (But things will all go boom if you write to the part that
821is "not there", because you'll be overwriting the last members of the
822preceding structure in memory.)
823
69ba284b 824We calculate the correction using the STRUCT_OFFSET macro on the first
a05ea1cf 825member present. If the allocated structure is smaller (no initial NV
69ba284b
NC
826actually allocated) then the net effect is to subtract the size of the NV
827from the pointer, to return a new pointer as if an initial NV were actually
a05ea1cf 828allocated. (We were using structures named *_allocated for this, but
69ba284b
NC
829this turned out to be a subtle bug, because a structure without an NV
830could have a lower alignment constraint, but the compiler is allowed to
831optimised accesses based on the alignment constraint of the actual pointer
832to the full structure, for example, using a single 64 bit load instruction
833because it "knows" that two adjacent 32 bit members will be 8-byte aligned.)
d2a0f284 834
a05ea1cf 835This is the same trick as was used for NV and IV bodies. Ironically it
d2a0f284 836doesn't need to be used for NV bodies any more, because NV is now at
5b306eef
DD
837the start of the structure. IV bodies, and also in some builds NV bodies,
838don't need it either, because they are no longer allocated.
d2a0f284
JC
839
840In turn, the new_body_* allocators call S_new_body(), which invokes
841new_body_inline macro, which takes a lock, and takes a body off the
1e30fcd5 842linked list at PL_body_roots[sv_type], calling Perl_more_bodies() if
d2a0f284
JC
843necessary to refresh an empty list. Then the lock is released, and
844the body is returned.
845
99816f8d 846Perl_more_bodies allocates a new arena, and carves it up into an array of N
d2a0f284
JC
847bodies, which it strings into a linked list. It looks up arena-size
848and body-size from the body_details table described below, thus
849supporting the multiple body-types.
850
851If PURIFY is defined, or PERL_ARENA_SIZE=0, arenas are not used, and
852the (new|del)_X*V macros are mapped directly to malloc/free.
853
d2a0f284
JC
854For each sv-type, struct body_details bodies_by_type[] carries
855parameters which control these aspects of SV handling:
856
857Arena_size determines whether arenas are used for this body type, and if
858so, how big they are. PURIFY or PERL_ARENA_SIZE=0 set this field to
859zero, forcing individual mallocs and frees.
860
861Body_size determines how big a body is, and therefore how many fit into
862each arena. Offset carries the body-pointer adjustment needed for
69ba284b 863"ghost fields", and is used in *_allocated macros.
d2a0f284
JC
864
865But its main purpose is to parameterize info needed in
866Perl_sv_upgrade(). The info here dramatically simplifies the function
69ba284b 867vs the implementation in 5.8.8, making it table-driven. All fields
d2a0f284
JC
868are used for this, except for arena_size.
869
870For the sv-types that have no bodies, arenas are not used, so those
871PL_body_roots[sv_type] are unused, and can be overloaded. In
872something of a special case, SVt_NULL is borrowed for HE arenas;
c6f8b1d0 873PL_body_roots[HE_SVSLOT=SVt_NULL] is filled by S_more_he, but the
d2a0f284 874bodies_by_type[SVt_NULL] slot is not used, as the table is not
c6f8b1d0 875available in hv.c.
d2a0f284 876
29489e7c
DM
877*/
878
bd81e77b 879struct body_details {
0fb58b32 880 U8 body_size; /* Size to allocate */
10666ae3 881 U8 copy; /* Size of structure to copy (may be shorter) */
5b306eef
DD
882 U8 offset; /* Size of unalloced ghost fields to first alloced field*/
883 PERL_BITFIELD8 type : 4; /* We have space for a sanity check. */
884 PERL_BITFIELD8 cant_upgrade : 1;/* Cannot upgrade this type */
885 PERL_BITFIELD8 zero_nv : 1; /* zero the NV when upgrading from this */
886 PERL_BITFIELD8 arena : 1; /* Allocated from an arena */
887 U32 arena_size; /* Size of arena to allocate */
bd81e77b 888};
29489e7c 889
bd81e77b
NC
890#define HADNV FALSE
891#define NONV TRUE
29489e7c 892
d2a0f284 893
bd81e77b
NC
894#ifdef PURIFY
895/* With -DPURFIY we allocate everything directly, and don't use arenas.
896 This seems a rather elegant way to simplify some of the code below. */
897#define HASARENA FALSE
898#else
899#define HASARENA TRUE
900#endif
901#define NOARENA FALSE
29489e7c 902
d2a0f284
JC
903/* Size the arenas to exactly fit a given number of bodies. A count
904 of 0 fits the max number bodies into a PERL_ARENA_SIZE.block,
905 simplifying the default. If count > 0, the arena is sized to fit
906 only that many bodies, allowing arenas to be used for large, rare
907 bodies (XPVFM, XPVIO) without undue waste. The arena size is
908 limited by PERL_ARENA_SIZE, so we can safely oversize the
909 declarations.
910 */
95db5f15
MB
911#define FIT_ARENA0(body_size) \
912 ((size_t)(PERL_ARENA_SIZE / body_size) * body_size)
913#define FIT_ARENAn(count,body_size) \
914 ( count * body_size <= PERL_ARENA_SIZE) \
915 ? count * body_size \
916 : FIT_ARENA0 (body_size)
917#define FIT_ARENA(count,body_size) \
cd1dc8e2 918 (U32)(count \
95db5f15 919 ? FIT_ARENAn (count, body_size) \
cd1dc8e2 920 : FIT_ARENA0 (body_size))
d2a0f284 921
bd81e77b
NC
922/* Calculate the length to copy. Specifically work out the length less any
923 final padding the compiler needed to add. See the comment in sv_upgrade
924 for why copying the padding proved to be a bug. */
29489e7c 925
bd81e77b
NC
926#define copy_length(type, last_member) \
927 STRUCT_OFFSET(type, last_member) \
daba3364 928 + sizeof (((type*)SvANY((const SV *)0))->last_member)
29489e7c 929
bd81e77b 930static const struct body_details bodies_by_type[] = {
829cd18a
NC
931 /* HEs use this offset for their arena. */
932 { 0, 0, 0, SVt_NULL, FALSE, NONV, NOARENA, 0 },
d2a0f284 933
db93c0c4
NC
934 /* IVs are in the head, so the allocation size is 0. */
935 { 0,
d2a0f284 936 sizeof(IV), /* This is used to copy out the IV body. */
10666ae3 937 STRUCT_OFFSET(XPVIV, xiv_iv), SVt_IV, FALSE, NONV,
db93c0c4 938 NOARENA /* IVS don't need an arena */, 0
d2a0f284
JC
939 },
940
5b306eef
DD
941#if NVSIZE <= IVSIZE
942 { 0, sizeof(NV),
943 STRUCT_OFFSET(XPVNV, xnv_u),
944 SVt_NV, FALSE, HADNV, NOARENA, 0 },
945#else
6e128786
NC
946 { sizeof(NV), sizeof(NV),
947 STRUCT_OFFSET(XPVNV, xnv_u),
948 SVt_NV, FALSE, HADNV, HASARENA, FIT_ARENA(0, sizeof(NV)) },
5b306eef 949#endif
d2a0f284 950
bc337e5c 951 { sizeof(XPV) - STRUCT_OFFSET(XPV, xpv_cur),
889d28b2
NC
952 copy_length(XPV, xpv_len) - STRUCT_OFFSET(XPV, xpv_cur),
953 + STRUCT_OFFSET(XPV, xpv_cur),
69ba284b 954 SVt_PV, FALSE, NONV, HASARENA,
889d28b2 955 FIT_ARENA(0, sizeof(XPV) - STRUCT_OFFSET(XPV, xpv_cur)) },
d2a0f284 956
d361b004
KW
957 { sizeof(XINVLIST) - STRUCT_OFFSET(XPV, xpv_cur),
958 copy_length(XINVLIST, is_offset) - STRUCT_OFFSET(XPV, xpv_cur),
959 + STRUCT_OFFSET(XPV, xpv_cur),
960 SVt_INVLIST, TRUE, NONV, HASARENA,
961 FIT_ARENA(0, sizeof(XINVLIST) - STRUCT_OFFSET(XPV, xpv_cur)) },
e94d9b54 962
bc337e5c 963 { sizeof(XPVIV) - STRUCT_OFFSET(XPV, xpv_cur),
889d28b2
NC
964 copy_length(XPVIV, xiv_u) - STRUCT_OFFSET(XPV, xpv_cur),
965 + STRUCT_OFFSET(XPV, xpv_cur),
966 SVt_PVIV, FALSE, NONV, HASARENA,
967 FIT_ARENA(0, sizeof(XPVIV) - STRUCT_OFFSET(XPV, xpv_cur)) },
d2a0f284 968
bc337e5c 969 { sizeof(XPVNV) - STRUCT_OFFSET(XPV, xpv_cur),
889d28b2
NC
970 copy_length(XPVNV, xnv_u) - STRUCT_OFFSET(XPV, xpv_cur),
971 + STRUCT_OFFSET(XPV, xpv_cur),
972 SVt_PVNV, FALSE, HADNV, HASARENA,
973 FIT_ARENA(0, sizeof(XPVNV) - STRUCT_OFFSET(XPV, xpv_cur)) },
d2a0f284 974
6e128786 975 { sizeof(XPVMG), copy_length(XPVMG, xnv_u), 0, SVt_PVMG, FALSE, HADNV,
d2a0f284 976 HASARENA, FIT_ARENA(0, sizeof(XPVMG)) },
4df7f6af 977
601dfd0a
NC
978 { sizeof(regexp),
979 sizeof(regexp),
980 0,
ecff11eb 981 SVt_REGEXP, TRUE, NONV, HASARENA,
eaeb1e7f 982 FIT_ARENA(0, sizeof(regexp))
5c35adbb 983 },
4df7f6af 984
10666ae3 985 { sizeof(XPVGV), sizeof(XPVGV), 0, SVt_PVGV, TRUE, HADNV,
d2a0f284
JC
986 HASARENA, FIT_ARENA(0, sizeof(XPVGV)) },
987
10666ae3 988 { sizeof(XPVLV), sizeof(XPVLV), 0, SVt_PVLV, TRUE, HADNV,
d2a0f284
JC
989 HASARENA, FIT_ARENA(0, sizeof(XPVLV)) },
990
601dfd0a 991 { sizeof(XPVAV),
4f7003f5 992 copy_length(XPVAV, xav_alloc),
601dfd0a 993 0,
69ba284b 994 SVt_PVAV, TRUE, NONV, HASARENA,
601dfd0a 995 FIT_ARENA(0, sizeof(XPVAV)) },
d2a0f284 996
601dfd0a 997 { sizeof(XPVHV),
359164a0 998 copy_length(XPVHV, xhv_max),
601dfd0a 999 0,
69ba284b 1000 SVt_PVHV, TRUE, NONV, HASARENA,
601dfd0a 1001 FIT_ARENA(0, sizeof(XPVHV)) },
d2a0f284 1002
601dfd0a
NC
1003 { sizeof(XPVCV),
1004 sizeof(XPVCV),
1005 0,
69ba284b 1006 SVt_PVCV, TRUE, NONV, HASARENA,
601dfd0a 1007 FIT_ARENA(0, sizeof(XPVCV)) },
69ba284b 1008
601dfd0a
NC
1009 { sizeof(XPVFM),
1010 sizeof(XPVFM),
1011 0,
69ba284b 1012 SVt_PVFM, TRUE, NONV, NOARENA,
601dfd0a 1013 FIT_ARENA(20, sizeof(XPVFM)) },
d2a0f284 1014
601dfd0a
NC
1015 { sizeof(XPVIO),
1016 sizeof(XPVIO),
1017 0,
b6f60916 1018 SVt_PVIO, TRUE, NONV, HASARENA,
601dfd0a 1019 FIT_ARENA(24, sizeof(XPVIO)) },
bd81e77b 1020};
29489e7c 1021
bd81e77b 1022#define new_body_allocated(sv_type) \
d2a0f284 1023 (void *)((char *)S_new_body(aTHX_ sv_type) \
bd81e77b 1024 - bodies_by_type[sv_type].offset)
29489e7c 1025
26359cfa
NC
1026/* return a thing to the free list */
1027
1028#define del_body(thing, root) \
1029 STMT_START { \
1030 void ** const thing_copy = (void **)thing; \
1031 *thing_copy = *root; \
1032 *root = (void*)thing_copy; \
1033 } STMT_END
29489e7c 1034
bd81e77b 1035#ifdef PURIFY
5b306eef
DD
1036#if !(NVSIZE <= IVSIZE)
1037# define new_XNV() safemalloc(sizeof(XPVNV))
1038#endif
beeec492
NC
1039#define new_XPVNV() safemalloc(sizeof(XPVNV))
1040#define new_XPVMG() safemalloc(sizeof(XPVMG))
29489e7c 1041
beeec492 1042#define del_XPVGV(p) safefree(p)
29489e7c 1043
bd81e77b 1044#else /* !PURIFY */
29489e7c 1045
5b306eef
DD
1046#if !(NVSIZE <= IVSIZE)
1047# define new_XNV() new_body_allocated(SVt_NV)
1048#endif
65ac1738 1049#define new_XPVNV() new_body_allocated(SVt_PVNV)
65ac1738 1050#define new_XPVMG() new_body_allocated(SVt_PVMG)
645c22ef 1051
26359cfa
NC
1052#define del_XPVGV(p) del_body(p + bodies_by_type[SVt_PVGV].offset, \
1053 &PL_body_roots[SVt_PVGV])
1d7c1841 1054
bd81e77b 1055#endif /* PURIFY */
93e68bfb 1056
bd81e77b 1057/* no arena for you! */
93e68bfb 1058
bd81e77b 1059#define new_NOARENA(details) \
beeec492 1060 safemalloc((details)->body_size + (details)->offset)
bd81e77b 1061#define new_NOARENAZ(details) \
beeec492 1062 safecalloc((details)->body_size + (details)->offset, 1)
d2a0f284 1063
1e30fcd5
NC
1064void *
1065Perl_more_bodies (pTHX_ const svtype sv_type, const size_t body_size,
1066 const size_t arena_size)
d2a0f284 1067{
d2a0f284 1068 void ** const root = &PL_body_roots[sv_type];
99816f8d
NC
1069 struct arena_desc *adesc;
1070 struct arena_set *aroot = (struct arena_set *) PL_body_arenas;
1071 unsigned int curr;
d2a0f284
JC
1072 char *start;
1073 const char *end;
02982131 1074 const size_t good_arena_size = Perl_malloc_good_size(arena_size);
20b7effb
JH
1075#if defined(DEBUGGING) && defined(PERL_GLOBAL_STRUCT)
1076 dVAR;
1077#endif
0b2d3faa 1078#if defined(DEBUGGING) && !defined(PERL_GLOBAL_STRUCT_PRIVATE)
23e9d66c
NC
1079 static bool done_sanity_check;
1080
0b2d3faa
JH
1081 /* PERL_GLOBAL_STRUCT_PRIVATE cannot coexist with global
1082 * variables like done_sanity_check. */
10666ae3 1083 if (!done_sanity_check) {
ea471437 1084 unsigned int i = SVt_LAST;
10666ae3
NC
1085
1086 done_sanity_check = TRUE;
1087
1088 while (i--)
1089 assert (bodies_by_type[i].type == i);
1090 }
1091#endif
1092
02982131 1093 assert(arena_size);
23e9d66c 1094
99816f8d
NC
1095 /* may need new arena-set to hold new arena */
1096 if (!aroot || aroot->curr >= aroot->set_size) {
1097 struct arena_set *newroot;
1098 Newxz(newroot, 1, struct arena_set);
1099 newroot->set_size = ARENAS_PER_SET;
1100 newroot->next = aroot;
1101 aroot = newroot;
1102 PL_body_arenas = (void *) newroot;
1103 DEBUG_m(PerlIO_printf(Perl_debug_log, "new arenaset %p\n", (void*)aroot));
1104 }
1105
1106 /* ok, now have arena-set with at least 1 empty/available arena-desc */
1107 curr = aroot->curr++;
1108 adesc = &(aroot->set[curr]);
1109 assert(!adesc->arena);
1110
1111 Newx(adesc->arena, good_arena_size, char);
1112 adesc->size = good_arena_size;
1113 adesc->utype = sv_type;
147e3846 1114 DEBUG_m(PerlIO_printf(Perl_debug_log, "arena %d added: %p size %" UVuf "\n",
99816f8d
NC
1115 curr, (void*)adesc->arena, (UV)good_arena_size));
1116
1117 start = (char *) adesc->arena;
d2a0f284 1118
29657bb6
NC
1119 /* Get the address of the byte after the end of the last body we can fit.
1120 Remember, this is integer division: */
02982131 1121 end = start + good_arena_size / body_size * body_size;
d2a0f284 1122
486ec47a 1123 /* computed count doesn't reflect the 1st slot reservation */
d8fca402
NC
1124#if defined(MYMALLOC) || defined(HAS_MALLOC_GOOD_SIZE)
1125 DEBUG_m(PerlIO_printf(Perl_debug_log,
1126 "arena %p end %p arena-size %d (from %d) type %d "
1127 "size %d ct %d\n",
02982131
NC
1128 (void*)start, (void*)end, (int)good_arena_size,
1129 (int)arena_size, sv_type, (int)body_size,
1130 (int)good_arena_size / (int)body_size));
d8fca402 1131#else
d2a0f284
JC
1132 DEBUG_m(PerlIO_printf(Perl_debug_log,
1133 "arena %p end %p arena-size %d type %d size %d ct %d\n",
6c9570dc 1134 (void*)start, (void*)end,
02982131
NC
1135 (int)arena_size, sv_type, (int)body_size,
1136 (int)good_arena_size / (int)body_size));
d8fca402 1137#endif
d2a0f284
JC
1138 *root = (void *)start;
1139
29657bb6
NC
1140 while (1) {
1141 /* Where the next body would start: */
d2a0f284 1142 char * const next = start + body_size;
29657bb6
NC
1143
1144 if (next >= end) {
1145 /* This is the last body: */
1146 assert(next == end);
1147
1148 *(void **)start = 0;
1149 return *root;
1150 }
1151
d2a0f284
JC
1152 *(void**) start = (void *)next;
1153 start = next;
1154 }
d2a0f284
JC
1155}
1156
1157/* grab a new thing from the free list, allocating more if necessary.
1158 The inline version is used for speed in hot routines, and the
1159 function using it serves the rest (unless PURIFY).
1160*/
1161#define new_body_inline(xpv, sv_type) \
1162 STMT_START { \
1163 void ** const r3wt = &PL_body_roots[sv_type]; \
11b79775 1164 xpv = (PTR_TBL_ENT_t*) (*((void **)(r3wt)) \
1e30fcd5 1165 ? *((void **)(r3wt)) : Perl_more_bodies(aTHX_ sv_type, \
02982131
NC
1166 bodies_by_type[sv_type].body_size,\
1167 bodies_by_type[sv_type].arena_size)); \
d2a0f284 1168 *(r3wt) = *(void**)(xpv); \
d2a0f284
JC
1169 } STMT_END
1170
1171#ifndef PURIFY
1172
1173STATIC void *
de37a194 1174S_new_body(pTHX_ const svtype sv_type)
d2a0f284 1175{
d2a0f284
JC
1176 void *xpv;
1177 new_body_inline(xpv, sv_type);
1178 return xpv;
1179}
1180
1181#endif
93e68bfb 1182
238b27b3
NC
1183static const struct body_details fake_rv =
1184 { 0, 0, 0, SVt_IV, FALSE, NONV, NOARENA, 0 };
1185
bd81e77b
NC
1186/*
1187=for apidoc sv_upgrade
93e68bfb 1188
bd81e77b
NC
1189Upgrade an SV to a more complex form. Generally adds a new body type to the
1190SV, then copies across as much information as possible from the old body.
9521ca61
FC
1191It croaks if the SV is already in a more complex form than requested. You
1192generally want to use the C<SvUPGRADE> macro wrapper, which checks the type
1193before calling C<sv_upgrade>, and hence does not croak. See also
fbe13c60 1194C<L</svtype>>.
93e68bfb 1195
bd81e77b 1196=cut
93e68bfb 1197*/
93e68bfb 1198
bd81e77b 1199void
5aaab254 1200Perl_sv_upgrade(pTHX_ SV *const sv, svtype new_type)
cac9b346 1201{
bd81e77b
NC
1202 void* old_body;
1203 void* new_body;
42d0e0b7 1204 const svtype old_type = SvTYPE(sv);
d2a0f284 1205 const struct body_details *new_type_details;
238b27b3 1206 const struct body_details *old_type_details
bd81e77b 1207 = bodies_by_type + old_type;
ed7df46e 1208 SV *referent = NULL;
cac9b346 1209
7918f24d
NC
1210 PERL_ARGS_ASSERT_SV_UPGRADE;
1211
1776cbe8
NC
1212 if (old_type == new_type)
1213 return;
1214
1215 /* This clause was purposefully added ahead of the early return above to
1216 the shared string hackery for (sort {$a <=> $b} keys %hash), with the
1217 inference by Nick I-S that it would fix other troublesome cases. See
1218 changes 7162, 7163 (f130fd4589cf5fbb24149cd4db4137c8326f49c1 and parent)
1219
1220 Given that shared hash key scalars are no longer PVIV, but PV, there is
1221 no longer need to unshare so as to free up the IVX slot for its proper
1222 purpose. So it's safe to move the early return earlier. */
1223
093085a8 1224 if (new_type > SVt_PVMG && SvIsCOW(sv)) {
bd81e77b
NC
1225 sv_force_normal_flags(sv, 0);
1226 }
cac9b346 1227
bd81e77b 1228 old_body = SvANY(sv);
de042e1d 1229
bd81e77b
NC
1230 /* Copying structures onto other structures that have been neatly zeroed
1231 has a subtle gotcha. Consider XPVMG
cac9b346 1232
bd81e77b
NC
1233 +------+------+------+------+------+-------+-------+
1234 | NV | CUR | LEN | IV | MAGIC | STASH |
1235 +------+------+------+------+------+-------+-------+
1236 0 4 8 12 16 20 24 28
645c22ef 1237
bd81e77b
NC
1238 where NVs are aligned to 8 bytes, so that sizeof that structure is
1239 actually 32 bytes long, with 4 bytes of padding at the end:
08742458 1240
bd81e77b
NC
1241 +------+------+------+------+------+-------+-------+------+
1242 | NV | CUR | LEN | IV | MAGIC | STASH | ??? |
1243 +------+------+------+------+------+-------+-------+------+
1244 0 4 8 12 16 20 24 28 32
08742458 1245
bd81e77b 1246 so what happens if you allocate memory for this structure:
30f9da9e 1247
bd81e77b
NC
1248 +------+------+------+------+------+-------+-------+------+------+...
1249 | NV | CUR | LEN | IV | MAGIC | STASH | GP | NAME |
1250 +------+------+------+------+------+-------+-------+------+------+...
1251 0 4 8 12 16 20 24 28 32 36
bfc44f79 1252
bd81e77b
NC
1253 zero it, then copy sizeof(XPVMG) bytes on top of it? Not quite what you
1254 expect, because you copy the area marked ??? onto GP. Now, ??? may have
1255 started out as zero once, but it's quite possible that it isn't. So now,
1256 rather than a nicely zeroed GP, you have it pointing somewhere random.
1257 Bugs ensue.
bfc44f79 1258
bd81e77b
NC
1259 (In fact, GP ends up pointing at a previous GP structure, because the
1260 principle cause of the padding in XPVMG getting garbage is a copy of
6c9e42f7
NC
1261 sizeof(XPVMG) bytes from a XPVGV structure in sv_unglob. Right now
1262 this happens to be moot because XPVGV has been re-ordered, with GP
1263 no longer after STASH)
30f9da9e 1264
bd81e77b
NC
1265 So we are careful and work out the size of used parts of all the
1266 structures. */
bfc44f79 1267
bd81e77b
NC
1268 switch (old_type) {
1269 case SVt_NULL:
1270 break;
1271 case SVt_IV:
4df7f6af 1272 if (SvROK(sv)) {
ed7df46e 1273 referent = SvRV(sv);
238b27b3
NC
1274 old_type_details = &fake_rv;
1275 if (new_type == SVt_NV)
1276 new_type = SVt_PVNV;
4df7f6af
NC
1277 } else {
1278 if (new_type < SVt_PVIV) {
1279 new_type = (new_type == SVt_NV)
1280 ? SVt_PVNV : SVt_PVIV;
1281 }
bd81e77b
NC
1282 }
1283 break;
1284 case SVt_NV:
1285 if (new_type < SVt_PVNV) {
1286 new_type = SVt_PVNV;
bd81e77b
NC
1287 }
1288 break;
bd81e77b
NC
1289 case SVt_PV:
1290 assert(new_type > SVt_PV);
6d59e610
LM
1291 STATIC_ASSERT_STMT(SVt_IV < SVt_PV);
1292 STATIC_ASSERT_STMT(SVt_NV < SVt_PV);
bd81e77b
NC
1293 break;
1294 case SVt_PVIV:
1295 break;
1296 case SVt_PVNV:
1297 break;
1298 case SVt_PVMG:
1299 /* Because the XPVMG of PL_mess_sv isn't allocated from the arena,
1300 there's no way that it can be safely upgraded, because perl.c
1301 expects to Safefree(SvANY(PL_mess_sv)) */
1302 assert(sv != PL_mess_sv);
bd81e77b
NC
1303 break;
1304 default:
2439e033 1305 if (UNLIKELY(old_type_details->cant_upgrade))
c81225bc
NC
1306 Perl_croak(aTHX_ "Can't upgrade %s (%" UVuf ") to %" UVuf,
1307 sv_reftype(sv, 0), (UV) old_type, (UV) new_type);
bd81e77b 1308 }
3376de98 1309
2439e033 1310 if (UNLIKELY(old_type > new_type))
3376de98
NC
1311 Perl_croak(aTHX_ "sv_upgrade from type %d down to type %d",
1312 (int)old_type, (int)new_type);
1313
2fa1109b 1314 new_type_details = bodies_by_type + new_type;
645c22ef 1315
bd81e77b
NC
1316 SvFLAGS(sv) &= ~SVTYPEMASK;
1317 SvFLAGS(sv) |= new_type;
932e9ff9 1318
ab4416c0
NC
1319 /* This can't happen, as SVt_NULL is <= all values of new_type, so one of
1320 the return statements above will have triggered. */
1321 assert (new_type != SVt_NULL);
bd81e77b 1322 switch (new_type) {
bd81e77b
NC
1323 case SVt_IV:
1324 assert(old_type == SVt_NULL);
dc6369ef 1325 SET_SVANY_FOR_BODYLESS_IV(sv);
bd81e77b
NC
1326 SvIV_set(sv, 0);
1327 return;
1328 case SVt_NV:
1329 assert(old_type == SVt_NULL);
5b306eef 1330#if NVSIZE <= IVSIZE
dc6369ef 1331 SET_SVANY_FOR_BODYLESS_NV(sv);
5b306eef 1332#else
bd81e77b 1333 SvANY(sv) = new_XNV();
5b306eef 1334#endif
bd81e77b
NC
1335 SvNV_set(sv, 0);
1336 return;
bd81e77b 1337 case SVt_PVHV:
bd81e77b 1338 case SVt_PVAV:
d2a0f284 1339 assert(new_type_details->body_size);
c1ae03ae
NC
1340
1341#ifndef PURIFY
1342 assert(new_type_details->arena);
d2a0f284 1343 assert(new_type_details->arena_size);
c1ae03ae 1344 /* This points to the start of the allocated area. */
d2a0f284
JC
1345 new_body_inline(new_body, new_type);
1346 Zero(new_body, new_type_details->body_size, char);
c1ae03ae
NC
1347 new_body = ((char *)new_body) - new_type_details->offset;
1348#else
1349 /* We always allocated the full length item with PURIFY. To do this
1350 we fake things so that arena is false for all 16 types.. */
1351 new_body = new_NOARENAZ(new_type_details);
1352#endif
1353 SvANY(sv) = new_body;
1354 if (new_type == SVt_PVAV) {
1355 AvMAX(sv) = -1;
1356 AvFILLp(sv) = -1;
1357 AvREAL_only(sv);
64484faa 1358 if (old_type_details->body_size) {
ac572bf4
NC
1359 AvALLOC(sv) = 0;
1360 } else {
1361 /* It will have been zeroed when the new body was allocated.
1362 Lets not write to it, in case it confuses a write-back
1363 cache. */
1364 }
78ac7dd9
NC
1365 } else {
1366 assert(!SvOK(sv));
1367 SvOK_off(sv);
1368#ifndef NODEFAULT_SHAREKEYS
1369 HvSHAREKEYS_on(sv); /* key-sharing on by default */
1370#endif
586fc6a3
SM
1371 /* start with PERL_HASH_DEFAULT_HvMAX+1 buckets: */
1372 HvMAX(sv) = PERL_HASH_DEFAULT_HvMAX;
c1ae03ae 1373 }
aeb18a1e 1374
bd81e77b
NC
1375 /* SVt_NULL isn't the only thing upgraded to AV or HV.
1376 The target created by newSVrv also is, and it can have magic.
1377 However, it never has SvPVX set.
1378 */
4df7f6af
NC
1379 if (old_type == SVt_IV) {
1380 assert(!SvROK(sv));
1381 } else if (old_type >= SVt_PV) {
bd81e77b
NC
1382 assert(SvPVX_const(sv) == 0);
1383 }
aeb18a1e 1384
bd81e77b 1385 if (old_type >= SVt_PVMG) {
e736a858 1386 SvMAGIC_set(sv, ((XPVMG*)old_body)->xmg_u.xmg_magic);
bd81e77b 1387 SvSTASH_set(sv, ((XPVMG*)old_body)->xmg_stash);
797c7171
NC
1388 } else {
1389 sv->sv_u.svu_array = NULL; /* or svu_hash */
bd81e77b
NC
1390 }
1391 break;
93e68bfb 1392
bd81e77b
NC
1393 case SVt_PVIV:
1394 /* XXX Is this still needed? Was it ever needed? Surely as there is
1395 no route from NV to PVIV, NOK can never be true */
1396 assert(!SvNOKp(sv));
1397 assert(!SvNOK(sv));
2b5060ae 1398 /* FALLTHROUGH */
bd81e77b
NC
1399 case SVt_PVIO:
1400 case SVt_PVFM:
bd81e77b
NC
1401 case SVt_PVGV:
1402 case SVt_PVCV:
1403 case SVt_PVLV:
d361b004 1404 case SVt_INVLIST:
12c45b25 1405 case SVt_REGEXP:
bd81e77b
NC
1406 case SVt_PVMG:
1407 case SVt_PVNV:
1408 case SVt_PV:
93e68bfb 1409
d2a0f284 1410 assert(new_type_details->body_size);
bd81e77b
NC
1411 /* We always allocated the full length item with PURIFY. To do this
1412 we fake things so that arena is false for all 16 types.. */
1413 if(new_type_details->arena) {
1414 /* This points to the start of the allocated area. */
d2a0f284
JC
1415 new_body_inline(new_body, new_type);
1416 Zero(new_body, new_type_details->body_size, char);
bd81e77b
NC
1417 new_body = ((char *)new_body) - new_type_details->offset;
1418 } else {
1419 new_body = new_NOARENAZ(new_type_details);
1420 }
1421 SvANY(sv) = new_body;
5e2fc214 1422
bd81e77b 1423 if (old_type_details->copy) {
f9ba3d20
NC
1424 /* There is now the potential for an upgrade from something without
1425 an offset (PVNV or PVMG) to something with one (PVCV, PVFM) */
1426 int offset = old_type_details->offset;
1427 int length = old_type_details->copy;
1428
1429 if (new_type_details->offset > old_type_details->offset) {
d4c19fe8 1430 const int difference
f9ba3d20
NC
1431 = new_type_details->offset - old_type_details->offset;
1432 offset += difference;
1433 length -= difference;
1434 }
1435 assert (length >= 0);
1436
1437 Copy((char *)old_body + offset, (char *)new_body + offset, length,
1438 char);
bd81e77b
NC
1439 }
1440
1441#ifndef NV_ZERO_IS_ALLBITS_ZERO
f2524eef 1442 /* If NV 0.0 is stores as all bits 0 then Zero() already creates a
e5ce394c
NC
1443 * correct 0.0 for us. Otherwise, if the old body didn't have an
1444 * NV slot, but the new one does, then we need to initialise the
1445 * freshly created NV slot with whatever the correct bit pattern is
1446 * for 0.0 */
e22a937e
NC
1447 if (old_type_details->zero_nv && !new_type_details->zero_nv
1448 && !isGV_with_GP(sv))
bd81e77b 1449 SvNV_set(sv, 0);
82048762 1450#endif
5e2fc214 1451
2439e033 1452 if (UNLIKELY(new_type == SVt_PVIO)) {
85dca89a 1453 IO * const io = MUTABLE_IO(sv);
d963bf01 1454 GV *iogv = gv_fetchpvs("IO::File::", GV_ADD, SVt_PVHV);
85dca89a
NC
1455
1456 SvOBJECT_on(io);
1457 /* Clear the stashcache because a new IO could overrule a package
1458 name */
103f5a36 1459 DEBUG_o(Perl_deb(aTHX_ "sv_upgrade clearing PL_stashcache\n"));
85dca89a
NC
1460 hv_clear(PL_stashcache);
1461
85dca89a 1462 SvSTASH_set(io, MUTABLE_HV(SvREFCNT_inc(GvHV(iogv))));
f2524eef 1463 IoPAGE_LEN(sv) = 60;
85dca89a 1464 }
2439e033 1465 if (UNLIKELY(new_type == SVt_REGEXP))
8d919b0a
FC
1466 sv->sv_u.svu_rx = (regexp *)new_body;
1467 else if (old_type < SVt_PV) {
ed7df46e 1468 /* referent will be NULL unless the old type was SVt_IV emulating
4df7f6af 1469 SVt_RV */
ed7df46e 1470 sv->sv_u.svu_rv = referent;
4df7f6af 1471 }
bd81e77b
NC
1472 break;
1473 default:
afd78fd5
JH
1474 Perl_croak(aTHX_ "panic: sv_upgrade to unknown type %lu",
1475 (unsigned long)new_type);
bd81e77b 1476 }
73171d91 1477
5b306eef
DD
1478 /* if this is zero, this is a body-less SVt_NULL, SVt_IV/SVt_RV,
1479 and sometimes SVt_NV */
1480 if (old_type_details->body_size) {
bd81e77b 1481#ifdef PURIFY
beeec492 1482 safefree(old_body);
bd81e77b 1483#else
bc786448
GG
1484 /* Note that there is an assumption that all bodies of types that
1485 can be upgraded came from arenas. Only the more complex non-
1486 upgradable types are allowed to be directly malloc()ed. */
1487 assert(old_type_details->arena);
bd81e77b
NC
1488 del_body((void*)((char*)old_body + old_type_details->offset),
1489 &PL_body_roots[old_type]);
1490#endif
1491 }
1492}
73171d91 1493
bd81e77b
NC
1494/*
1495=for apidoc sv_backoff
73171d91 1496
fde67290 1497Remove any string offset. You should normally use the C<SvOOK_off> macro
bd81e77b 1498wrapper instead.
73171d91 1499
bd81e77b 1500=cut
73171d91
NC
1501*/
1502
fa7a1e49
DD
1503/* prior to 5.000 stable, this function returned the new OOK-less SvFLAGS
1504 prior to 5.23.4 this function always returned 0
1505*/
1506
1507void
ddeaf645 1508Perl_sv_backoff(SV *const sv)
bd81e77b 1509{
69240efd 1510 STRLEN delta;
7a4bba22 1511 const char * const s = SvPVX_const(sv);
7918f24d
NC
1512
1513 PERL_ARGS_ASSERT_SV_BACKOFF;
7918f24d 1514
bd81e77b
NC
1515 assert(SvOOK(sv));
1516 assert(SvTYPE(sv) != SVt_PVHV);
1517 assert(SvTYPE(sv) != SVt_PVAV);
7a4bba22 1518
69240efd
NC
1519 SvOOK_offset(sv, delta);
1520
7a4bba22
NC
1521 SvLEN_set(sv, SvLEN(sv) + delta);
1522 SvPV_set(sv, SvPVX(sv) - delta);
bd81e77b 1523 SvFLAGS(sv) &= ~SVf_OOK;
fa7a1e49
DD
1524 Move(s, SvPVX(sv), SvCUR(sv)+1, char);
1525 return;
bd81e77b 1526}
73171d91 1527
03885497
DM
1528
1529/* forward declaration */
1530static void S_sv_uncow(pTHX_ SV * const sv, const U32 flags);
1531
1532
bd81e77b
NC
1533/*
1534=for apidoc sv_grow
73171d91 1535
bd81e77b
NC
1536Expands the character buffer in the SV. If necessary, uses C<sv_unref> and
1537upgrades the SV to C<SVt_PV>. Returns a pointer to the character buffer.
1538Use the C<SvGROW> wrapper instead.
93e68bfb 1539
bd81e77b
NC
1540=cut
1541*/
93e68bfb 1542
e0060e30 1543
bd81e77b 1544char *
5aaab254 1545Perl_sv_grow(pTHX_ SV *const sv, STRLEN newlen)
bd81e77b 1546{
eb578fdb 1547 char *s;
93e68bfb 1548
7918f24d
NC
1549 PERL_ARGS_ASSERT_SV_GROW;
1550
bd81e77b
NC
1551 if (SvROK(sv))
1552 sv_unref(sv);
1553 if (SvTYPE(sv) < SVt_PV) {
1554 sv_upgrade(sv, SVt_PV);
1555 s = SvPVX_mutable(sv);
1556 }
1557 else if (SvOOK(sv)) { /* pv is offset? */
1558 sv_backoff(sv);
1559 s = SvPVX_mutable(sv);
1560 if (newlen > SvLEN(sv))
1561 newlen += 10 * (newlen - SvCUR(sv)); /* avoid copy each time */
bd81e77b
NC
1562 }
1563 else
db2c6cb3 1564 {
e0060e30 1565 if (SvIsCOW(sv)) S_sv_uncow(aTHX_ sv, 0);
bd81e77b 1566 s = SvPVX_mutable(sv);
db2c6cb3 1567 }
aeb18a1e 1568
93c10d60 1569#ifdef PERL_COPY_ON_WRITE
cbcb2a16 1570 /* the new COW scheme uses SvPVX(sv)[SvLEN(sv)-1] (if spare)
3c239bea 1571 * to store the COW count. So in general, allocate one more byte than
cbcb2a16
DM
1572 * asked for, to make it likely this byte is always spare: and thus
1573 * make more strings COW-able.
fe546b38 1574 *
fa8f4f85
TC
1575 * Only increment if the allocation isn't MEM_SIZE_MAX,
1576 * otherwise it will wrap to 0.
1577 */
fe546b38 1578 if ( newlen != MEM_SIZE_MAX )
cbcb2a16
DM
1579 newlen++;
1580#endif
1581
ce861ea7
YO
1582#if defined(PERL_USE_MALLOC_SIZE) && defined(Perl_safesysmalloc_size)
1583#define PERL_UNWARANTED_CHUMMINESS_WITH_MALLOC
1584#endif
1585
bd81e77b 1586 if (newlen > SvLEN(sv)) { /* need more room? */
f1200559 1587 STRLEN minlen = SvCUR(sv);
3c239bea 1588 minlen += (minlen >> PERL_STRLEN_EXPAND_SHIFT) + 10;
f1200559
WH
1589 if (newlen < minlen)
1590 newlen = minlen;
ce861ea7 1591#ifndef PERL_UNWARANTED_CHUMMINESS_WITH_MALLOC
7c641603
KW
1592
1593 /* Don't round up on the first allocation, as odds are pretty good that
1594 * the initial request is accurate as to what is really needed */
ce861ea7 1595 if (SvLEN(sv)) {
9efda33a
TC
1596 STRLEN rounded = PERL_STRLEN_ROUNDUP(newlen);
1597 if (rounded > newlen)
1598 newlen = rounded;
ce861ea7 1599 }
bd81e77b 1600#endif
98653f18 1601 if (SvLEN(sv) && s) {
10edeb5d 1602 s = (char*)saferealloc(s, newlen);
bd81e77b
NC
1603 }
1604 else {
10edeb5d 1605 s = (char*)safemalloc(newlen);
bd81e77b 1606 if (SvPVX_const(sv) && SvCUR(sv)) {
0a5fcc38 1607 Move(SvPVX_const(sv), s, SvCUR(sv), char);
bd81e77b
NC
1608 }
1609 }
1610 SvPV_set(sv, s);
ce861ea7 1611#ifdef PERL_UNWARANTED_CHUMMINESS_WITH_MALLOC
98653f18
NC
1612 /* Do this here, do it once, do it right, and then we will never get
1613 called back into sv_grow() unless there really is some growing
1614 needed. */
ca7c1a29 1615 SvLEN_set(sv, Perl_safesysmalloc_size(s));
98653f18 1616#else
bd81e77b 1617 SvLEN_set(sv, newlen);
98653f18 1618#endif
bd81e77b
NC
1619 }
1620 return s;
1621}
aeb18a1e 1622
bd81e77b
NC
1623/*
1624=for apidoc sv_setiv
932e9ff9 1625
bd81e77b 1626Copies an integer into the given SV, upgrading first if necessary.
fbe13c60 1627Does not handle 'set' magic. See also C<L</sv_setiv_mg>>.
463ee0b2 1628
bd81e77b
NC
1629=cut
1630*/
463ee0b2 1631
bd81e77b 1632void
5aaab254 1633Perl_sv_setiv(pTHX_ SV *const sv, const IV i)
bd81e77b 1634{
7918f24d
NC
1635 PERL_ARGS_ASSERT_SV_SETIV;
1636
bd81e77b
NC
1637 SV_CHECK_THINKFIRST_COW_DROP(sv);
1638 switch (SvTYPE(sv)) {
1639 case SVt_NULL:
bd81e77b 1640 case SVt_NV:
3376de98 1641 sv_upgrade(sv, SVt_IV);
bd81e77b 1642 break;
bd81e77b
NC
1643 case SVt_PV:
1644 sv_upgrade(sv, SVt_PVIV);
1645 break;
463ee0b2 1646
bd81e77b 1647 case SVt_PVGV:
6e592b3a
BM
1648 if (!isGV_with_GP(sv))
1649 break;
bd81e77b
NC
1650 case SVt_PVAV:
1651 case SVt_PVHV:
1652 case SVt_PVCV:
1653 case SVt_PVFM:
1654 case SVt_PVIO:
22e74366 1655 /* diag_listed_as: Can't coerce %s to %s in %s */
bd81e77b
NC
1656 Perl_croak(aTHX_ "Can't coerce %s to integer in %s", sv_reftype(sv,0),
1657 OP_DESC(PL_op));
c9a0dcdc 1658 NOT_REACHED; /* NOTREACHED */
0103ca14 1659 break;
42d0e0b7 1660 default: NOOP;
bd81e77b
NC
1661 }
1662 (void)SvIOK_only(sv); /* validate number */
1663 SvIV_set(sv, i);
1664 SvTAINT(sv);
1665}
932e9ff9 1666
bd81e77b
NC
1667/*
1668=for apidoc sv_setiv_mg
d33b2eba 1669
bd81e77b 1670Like C<sv_setiv>, but also handles 'set' magic.
1c846c1f 1671
bd81e77b
NC
1672=cut
1673*/
d33b2eba 1674
bd81e77b 1675void
5aaab254 1676Perl_sv_setiv_mg(pTHX_ SV *const sv, const IV i)
bd81e77b 1677{
7918f24d
NC
1678 PERL_ARGS_ASSERT_SV_SETIV_MG;
1679
bd81e77b
NC
1680 sv_setiv(sv,i);
1681 SvSETMAGIC(sv);
1682}
727879eb 1683
bd81e77b
NC
1684/*
1685=for apidoc sv_setuv
d33b2eba 1686
bd81e77b 1687Copies an unsigned integer into the given SV, upgrading first if necessary.
fbe13c60 1688Does not handle 'set' magic. See also C<L</sv_setuv_mg>>.
9b94d1dd 1689
bd81e77b
NC
1690=cut
1691*/
d33b2eba 1692
bd81e77b 1693void
5aaab254 1694Perl_sv_setuv(pTHX_ SV *const sv, const UV u)
bd81e77b 1695{
7918f24d
NC
1696 PERL_ARGS_ASSERT_SV_SETUV;
1697
013abb9b
NC
1698 /* With the if statement to ensure that integers are stored as IVs whenever
1699 possible:
bd81e77b 1700 u=1.49 s=0.52 cu=72.49 cs=10.64 scripts=270 tests=20865
d33b2eba 1701
bd81e77b
NC
1702 without
1703 u=1.35 s=0.47 cu=73.45 cs=11.43 scripts=270 tests=20865
1c846c1f 1704
013abb9b
NC
1705 If you wish to remove the following if statement, so that this routine
1706 (and its callers) always return UVs, please benchmark to see what the
1707 effect is. Modern CPUs may be different. Or may not :-)
bd81e77b
NC
1708 */
1709 if (u <= (UV)IV_MAX) {
1710 sv_setiv(sv, (IV)u);
1711 return;
1712 }
1713 sv_setiv(sv, 0);
1714 SvIsUV_on(sv);
1715 SvUV_set(sv, u);
1716}
d33b2eba 1717
bd81e77b
NC
1718/*
1719=for apidoc sv_setuv_mg
727879eb 1720
bd81e77b 1721Like C<sv_setuv>, but also handles 'set' magic.
9b94d1dd 1722
bd81e77b
NC
1723=cut
1724*/
5e2fc214 1725
bd81e77b 1726void
5aaab254 1727Perl_sv_setuv_mg(pTHX_ SV *const sv, const UV u)
bd81e77b 1728{
7918f24d
NC
1729 PERL_ARGS_ASSERT_SV_SETUV_MG;
1730
bd81e77b
NC
1731 sv_setuv(sv,u);
1732 SvSETMAGIC(sv);
1733}
5e2fc214 1734
954c1994 1735/*
bd81e77b 1736=for apidoc sv_setnv
954c1994 1737
bd81e77b 1738Copies a double into the given SV, upgrading first if necessary.
fbe13c60 1739Does not handle 'set' magic. See also C<L</sv_setnv_mg>>.
954c1994
GS
1740
1741=cut
1742*/
1743
63f97190 1744void
5aaab254 1745Perl_sv_setnv(pTHX_ SV *const sv, const NV num)
79072805 1746{
7918f24d
NC
1747 PERL_ARGS_ASSERT_SV_SETNV;
1748
bd81e77b
NC
1749 SV_CHECK_THINKFIRST_COW_DROP(sv);
1750 switch (SvTYPE(sv)) {
79072805 1751 case SVt_NULL:
79072805 1752 case SVt_IV:
bd81e77b 1753 sv_upgrade(sv, SVt_NV);
79072805
LW
1754 break;
1755 case SVt_PV:
79072805 1756 case SVt_PVIV:
bd81e77b 1757 sv_upgrade(sv, SVt_PVNV);
79072805 1758 break;
bd4b1eb5 1759
bd4b1eb5 1760 case SVt_PVGV:
6e592b3a
BM
1761 if (!isGV_with_GP(sv))
1762 break;
bd81e77b
NC
1763 case SVt_PVAV:
1764 case SVt_PVHV:
79072805 1765 case SVt_PVCV:
bd81e77b
NC
1766 case SVt_PVFM:
1767 case SVt_PVIO:
22e74366 1768 /* diag_listed_as: Can't coerce %s to %s in %s */
bd81e77b 1769 Perl_croak(aTHX_ "Can't coerce %s to number in %s", sv_reftype(sv,0),
94bbb3f4 1770 OP_DESC(PL_op));
c9a0dcdc 1771 NOT_REACHED; /* NOTREACHED */
0103ca14 1772 break;
42d0e0b7 1773 default: NOOP;
2068cd4d 1774 }
bd81e77b
NC
1775 SvNV_set(sv, num);
1776 (void)SvNOK_only(sv); /* validate number */
1777 SvTAINT(sv);
79072805
LW
1778}
1779
645c22ef 1780/*
bd81e77b 1781=for apidoc sv_setnv_mg
645c22ef 1782
bd81e77b 1783Like C<sv_setnv>, but also handles 'set' magic.
645c22ef
DM
1784
1785=cut
1786*/
1787
bd81e77b 1788void
5aaab254 1789Perl_sv_setnv_mg(pTHX_ SV *const sv, const NV num)
79072805 1790{
7918f24d
NC
1791 PERL_ARGS_ASSERT_SV_SETNV_MG;
1792
bd81e77b
NC
1793 sv_setnv(sv,num);
1794 SvSETMAGIC(sv);
79072805
LW
1795}
1796
3f7602fa
TC
1797/* Return a cleaned-up, printable version of sv, for non-numeric, or
1798 * not incrementable warning display.
1799 * Originally part of S_not_a_number().
1800 * The return value may be != tmpbuf.
bd81e77b 1801 */
954c1994 1802
3f7602fa
TC
1803STATIC const char *
1804S_sv_display(pTHX_ SV *const sv, char *tmpbuf, STRLEN tmpbuf_size) {
1805 const char *pv;
94463019 1806
3f7602fa 1807 PERL_ARGS_ASSERT_SV_DISPLAY;
7918f24d 1808
94463019 1809 if (DO_UTF8(sv)) {
3f7602fa 1810 SV *dsv = newSVpvs_flags("", SVs_TEMP);
37b8cdd1 1811 pv = sv_uni_display(dsv, sv, 32, UNI_DISPLAY_ISPRINT);
94463019
JH
1812 } else {
1813 char *d = tmpbuf;
3f7602fa 1814 const char * const limit = tmpbuf + tmpbuf_size - 8;
94463019
JH
1815 /* each *s can expand to 4 chars + "...\0",
1816 i.e. need room for 8 chars */
ecdeb87c 1817
00b6aa41
AL
1818 const char *s = SvPVX_const(sv);
1819 const char * const end = s + SvCUR(sv);
1820 for ( ; s < end && d < limit; s++ ) {
94463019 1821 int ch = *s & 0xFF;
bd27cf70 1822 if (! isASCII(ch) && !isPRINT_LC(ch)) {
94463019
JH
1823 *d++ = 'M';
1824 *d++ = '-';
bd27cf70
KW
1825
1826 /* Map to ASCII "equivalent" of Latin1 */
1827 ch = LATIN1_TO_NATIVE(NATIVE_TO_LATIN1(ch) & 127);
94463019
JH
1828 }
1829 if (ch == '\n') {
1830 *d++ = '\\';
1831 *d++ = 'n';
1832 }
1833 else if (ch == '\r') {
1834 *d++ = '\\';
1835 *d++ = 'r';
1836 }
1837 else if (ch == '\f') {
1838 *d++ = '\\';
1839 *d++ = 'f';
1840 }
1841 else if (ch == '\\') {
1842 *d++ = '\\';
1843 *d++ = '\\';
1844 }
1845 else if (ch == '\0') {
1846 *d++ = '\\';
1847 *d++ = '0';
1848 }
1849 else if (isPRINT_LC(ch))
1850 *d++ = ch;
1851 else {
1852 *d++ = '^';
1853 *d++ = toCTRL(ch);
1854 }
1855 }
1856 if (s < end) {
1857 *d++ = '.';
1858 *d++ = '.';
1859 *d++ = '.';
1860 }
1861 *d = '\0';
1862 pv = tmpbuf;
a0d0e21e 1863 }
a0d0e21e 1864
3f7602fa
TC
1865 return pv;
1866}
1867
1868/* Print an "isn't numeric" warning, using a cleaned-up,
1869 * printable version of the offending string
1870 */
1871
1872STATIC void
1873S_not_a_number(pTHX_ SV *const sv)
1874{
3f7602fa
TC
1875 char tmpbuf[64];
1876 const char *pv;
1877
1878 PERL_ARGS_ASSERT_NOT_A_NUMBER;
1879
1880 pv = sv_display(sv, tmpbuf, sizeof(tmpbuf));
1881
533c011a 1882 if (PL_op)
9014280d 1883 Perl_warner(aTHX_ packWARN(WARN_NUMERIC),
734856a2 1884 /* diag_listed_as: Argument "%s" isn't numeric%s */
94463019
JH
1885 "Argument \"%s\" isn't numeric in %s", pv,
1886 OP_DESC(PL_op));
a0d0e21e 1887 else
9014280d 1888 Perl_warner(aTHX_ packWARN(WARN_NUMERIC),
734856a2 1889 /* diag_listed_as: Argument "%s" isn't numeric%s */
94463019 1890 "Argument \"%s\" isn't numeric", pv);
a0d0e21e
LW
1891}
1892
3f7602fa
TC
1893STATIC void
1894S_not_incrementable(pTHX_ SV *const sv) {
3f7602fa
TC
1895 char tmpbuf[64];
1896 const char *pv;
1897
1898 PERL_ARGS_ASSERT_NOT_INCREMENTABLE;
1899
1900 pv = sv_display(sv, tmpbuf, sizeof(tmpbuf));
1901
1902 Perl_warner(aTHX_ packWARN(WARN_NUMERIC),
1903 "Argument \"%s\" treated as 0 in increment (++)", pv);
1904}
1905
c2988b20
NC
1906/*
1907=for apidoc looks_like_number
1908
645c22ef
DM
1909Test if the content of an SV looks like a number (or is a number).
1910C<Inf> and C<Infinity> are treated as numbers (so will not issue a
796b6530 1911non-numeric warning), even if your C<atof()> doesn't grok them. Get-magic is
f52e41ad 1912ignored.
c2988b20
NC
1913
1914=cut
1915*/
1916
1917I32
aad570aa 1918Perl_looks_like_number(pTHX_ SV *const sv)
c2988b20 1919{
eb578fdb 1920 const char *sbegin;
c2988b20 1921 STRLEN len;
ea2485eb 1922 int numtype;
c2988b20 1923
7918f24d
NC
1924 PERL_ARGS_ASSERT_LOOKS_LIKE_NUMBER;
1925
f52e41ad
FC
1926 if (SvPOK(sv) || SvPOKp(sv)) {
1927 sbegin = SvPV_nomg_const(sv, len);
c2988b20 1928 }
c2988b20 1929 else
e0ab1c0e 1930 return SvFLAGS(sv) & (SVf_NOK|SVp_NOK|SVf_IOK|SVp_IOK);
ea2485eb
JH
1931 numtype = grok_number(sbegin, len, NULL);
1932 return ((numtype & IS_NUMBER_TRAILING)) ? 0 : numtype;
c2988b20 1933}
25da4f38 1934
19f6321d
NC
1935STATIC bool
1936S_glob_2number(pTHX_ GV * const gv)
180488f8 1937{
7918f24d
NC
1938 PERL_ARGS_ASSERT_GLOB_2NUMBER;
1939
675c862f
AL
1940 /* We know that all GVs stringify to something that is not-a-number,
1941 so no need to test that. */
1942 if (ckWARN(WARN_NUMERIC))
8e629ff4
FC
1943 {
1944 SV *const buffer = sv_newmortal();
1945 gv_efullname3(buffer, gv, "*");
675c862f 1946 not_a_number(buffer);
8e629ff4 1947 }
675c862f
AL
1948 /* We just want something true to return, so that S_sv_2iuv_common
1949 can tail call us and return true. */
19f6321d 1950 return TRUE;
675c862f
AL
1951}
1952
25da4f38
IZ
1953/* Actually, ISO C leaves conversion of UV to IV undefined, but
1954 until proven guilty, assume that things are not that bad... */
1955
645c22ef
DM
1956/*
1957 NV_PRESERVES_UV:
1958
1959 As 64 bit platforms often have an NV that doesn't preserve all bits of
28e5dec8
JH
1960 an IV (an assumption perl has been based on to date) it becomes necessary
1961 to remove the assumption that the NV always carries enough precision to
1962 recreate the IV whenever needed, and that the NV is the canonical form.
1963 Instead, IV/UV and NV need to be given equal rights. So as to not lose
645c22ef 1964 precision as a side effect of conversion (which would lead to insanity
28e5dec8 1965 and the dragon(s) in t/op/numconvert.t getting very angry) the intent is
8a4a3196
KW
1966 1) to distinguish between IV/UV/NV slots that have a valid conversion cached
1967 where precision was lost, and IV/UV/NV slots that have a valid conversion
1968 which has lost no precision
645c22ef 1969 2) to ensure that if a numeric conversion to one form is requested that
28e5dec8
JH
1970 would lose precision, the precise conversion (or differently
1971 imprecise conversion) is also performed and cached, to prevent
1972 requests for different numeric formats on the same SV causing
1973 lossy conversion chains. (lossless conversion chains are perfectly
1974 acceptable (still))
1975
1976
1977 flags are used:
1978 SvIOKp is true if the IV slot contains a valid value
1979 SvIOK is true only if the IV value is accurate (UV if SvIOK_UV true)
1980 SvNOKp is true if the NV slot contains a valid value
1981 SvNOK is true only if the NV value is accurate
1982
1983 so
645c22ef 1984 while converting from PV to NV, check to see if converting that NV to an
28e5dec8
JH
1985 IV(or UV) would lose accuracy over a direct conversion from PV to
1986 IV(or UV). If it would, cache both conversions, return NV, but mark
1987 SV as IOK NOKp (ie not NOK).
1988
645c22ef 1989 While converting from PV to IV, check to see if converting that IV to an
28e5dec8
JH
1990 NV would lose accuracy over a direct conversion from PV to NV. If it
1991 would, cache both conversions, flag similarly.
1992
1993 Before, the SV value "3.2" could become NV=3.2 IV=3 NOK, IOK quite
1994 correctly because if IV & NV were set NV *always* overruled.
645c22ef
DM
1995 Now, "3.2" will become NV=3.2 IV=3 NOK, IOKp, because the flag's meaning
1996 changes - now IV and NV together means that the two are interchangeable:
28e5dec8 1997 SvIVX == (IV) SvNVX && SvNVX == (NV) SvIVX;
d460ef45 1998
645c22ef
DM
1999 The benefit of this is that operations such as pp_add know that if
2000 SvIOK is true for both left and right operands, then integer addition
2001 can be used instead of floating point (for cases where the result won't
2002 overflow). Before, floating point was always used, which could lead to
28e5dec8
JH
2003 loss of precision compared with integer addition.
2004
2005 * making IV and NV equal status should make maths accurate on 64 bit
2006 platforms
2007 * may speed up maths somewhat if pp_add and friends start to use
645c22ef 2008 integers when possible instead of fp. (Hopefully the overhead in
28e5dec8
JH
2009 looking for SvIOK and checking for overflow will not outweigh the
2010 fp to integer speedup)
2011 * will slow down integer operations (callers of SvIV) on "inaccurate"
2012 values, as the change from SvIOK to SvIOKp will cause a call into
2013 sv_2iv each time rather than a macro access direct to the IV slot
2014 * should speed up number->string conversion on integers as IV is
645c22ef 2015 favoured when IV and NV are equally accurate
28e5dec8
JH
2016
2017 ####################################################################
645c22ef
DM
2018 You had better be using SvIOK_notUV if you want an IV for arithmetic:
2019 SvIOK is true if (IV or UV), so you might be getting (IV)SvUV.
2020 On the other hand, SvUOK is true iff UV.
28e5dec8
JH
2021 ####################################################################
2022
645c22ef 2023 Your mileage will vary depending your CPU's relative fp to integer
28e5dec8
JH
2024 performance ratio.
2025*/
2026
2027#ifndef NV_PRESERVES_UV
645c22ef
DM
2028# define IS_NUMBER_UNDERFLOW_IV 1
2029# define IS_NUMBER_UNDERFLOW_UV 2
2030# define IS_NUMBER_IV_AND_UV 2
2031# define IS_NUMBER_OVERFLOW_IV 4
2032# define IS_NUMBER_OVERFLOW_UV 5
2033
2034/* sv_2iuv_non_preserve(): private routine for use by sv_2iv() and sv_2uv() */
28e5dec8
JH
2035
2036/* For sv_2nv these three cases are "SvNOK and don't bother casting" */
2037STATIC int
5aaab254 2038S_sv_2iuv_non_preserve(pTHX_ SV *const sv
47031da6
NC
2039# ifdef DEBUGGING
2040 , I32 numtype
2041# endif
2042 )
28e5dec8 2043{
7918f24d 2044 PERL_ARGS_ASSERT_SV_2IUV_NON_PRESERVE;
23491f1d 2045 PERL_UNUSED_CONTEXT;
7918f24d 2046
147e3846 2047 DEBUG_c(PerlIO_printf(Perl_debug_log,"sv_2iuv_non '%s', IV=0x%" UVxf " NV=%" NVgf " inttype=%" UVXf "\n", SvPVX_const(sv), SvIVX(sv), SvNVX(sv), (UV)numtype));
28e5dec8
JH
2048 if (SvNVX(sv) < (NV)IV_MIN) {
2049 (void)SvIOKp_on(sv);
2050 (void)SvNOK_on(sv);
45977657 2051 SvIV_set(sv, IV_MIN);
28e5dec8
JH
2052 return IS_NUMBER_UNDERFLOW_IV;
2053 }
2054 if (SvNVX(sv) > (NV)UV_MAX) {
2055 (void)SvIOKp_on(sv);
2056 (void)SvNOK_on(sv);
2057 SvIsUV_on(sv);
607fa7f2 2058 SvUV_set(sv, UV_MAX);
28e5dec8
JH
2059 return IS_NUMBER_OVERFLOW_UV;
2060 }
c2988b20
NC
2061 (void)SvIOKp_on(sv);
2062 (void)SvNOK_on(sv);
2063 /* Can't use strtol etc to convert this string. (See truth table in
2064 sv_2iv */
2065 if (SvNVX(sv) <= (UV)IV_MAX) {
45977657 2066 SvIV_set(sv, I_V(SvNVX(sv)));
659c4b96 2067 if ((NV)(SvIVX(sv)) == SvNVX(sv)) {
c2988b20
NC
2068 SvIOK_on(sv); /* Integer is precise. NOK, IOK */
2069 } else {
2070 /* Integer is imprecise. NOK, IOKp */
2071 }
2072 return SvNVX(sv) < 0 ? IS_NUMBER_UNDERFLOW_UV : IS_NUMBER_IV_AND_UV;
2073 }
2074 SvIsUV_on(sv);
607fa7f2 2075 SvUV_set(sv, U_V(SvNVX(sv)));
659c4b96 2076 if ((NV)(SvUVX(sv)) == SvNVX(sv)) {
c2988b20
NC
2077 if (SvUVX(sv) == UV_MAX) {
2078 /* As we know that NVs don't preserve UVs, UV_MAX cannot
2079 possibly be preserved by NV. Hence, it must be overflow.
2080 NOK, IOKp */
2081 return IS_NUMBER_OVERFLOW_UV;
2082 }
2083 SvIOK_on(sv); /* Integer is precise. NOK, UOK */
2084 } else {
2085 /* Integer is imprecise. NOK, IOKp */
28e5dec8 2086 }
c2988b20 2087 return IS_NUMBER_OVERFLOW_IV;
28e5dec8 2088}
645c22ef
DM
2089#endif /* !NV_PRESERVES_UV*/
2090
a13f4dff 2091/* If numtype is infnan, set the NV of the sv accordingly.
5564cd7f 2092 * If numtype is anything else, try setting the NV using Atof(PV). */
3c81f0b3
DD
2093#ifdef USING_MSVC6
2094# pragma warning(push)
2095# pragma warning(disable:4756;disable:4056)
2096#endif
a13f4dff 2097static void
3823048b 2098S_sv_setnv(pTHX_ SV* sv, int numtype)
a13f4dff 2099{
07925c5e 2100 bool pok = cBOOL(SvPOK(sv));
5564cd7f 2101 bool nok = FALSE;
a7157111 2102#ifdef NV_INF
a13f4dff
JH
2103 if ((numtype & IS_NUMBER_INFINITY)) {
2104 SvNV_set(sv, (numtype & IS_NUMBER_NEG) ? -NV_INF : NV_INF);
5564cd7f 2105 nok = TRUE;
a7157111
JH
2106 } else
2107#endif
2108#ifdef NV_NAN
2109 if ((numtype & IS_NUMBER_NAN)) {
3823048b 2110 SvNV_set(sv, NV_NAN);
d48bd569 2111 nok = TRUE;
a7157111
JH
2112 } else
2113#endif
2114 if (pok) {
a13f4dff 2115 SvNV_set(sv, Atof(SvPVX_const(sv)));
d48bd569
JH
2116 /* Purposefully no true nok here, since we don't want to blow
2117 * away the possible IOK/UV of an existing sv. */
2118 }
5564cd7f 2119 if (nok) {
d48bd569 2120 SvNOK_only(sv); /* No IV or UV please, this is pure infnan. */
5564cd7f
JH
2121 if (pok)
2122 SvPOK_on(sv); /* PV is okay, though. */
2123 }
a13f4dff 2124}
3c81f0b3
DD
2125#ifdef USING_MSVC6
2126# pragma warning(pop)
2127#endif
a13f4dff 2128
af359546 2129STATIC bool
7918f24d
NC
2130S_sv_2iuv_common(pTHX_ SV *const sv)
2131{
7918f24d
NC
2132 PERL_ARGS_ASSERT_SV_2IUV_COMMON;
2133
af359546 2134 if (SvNOKp(sv)) {
28e5dec8
JH
2135 /* erm. not sure. *should* never get NOKp (without NOK) from sv_2nv
2136 * without also getting a cached IV/UV from it at the same time
2137 * (ie PV->NV conversion should detect loss of accuracy and cache
af359546
NC
2138 * IV or UV at same time to avoid this. */
2139 /* IV-over-UV optimisation - choose to cache IV if possible */
25da4f38
IZ
2140
2141 if (SvTYPE(sv) == SVt_NV)
2142 sv_upgrade(sv, SVt_PVNV);
2143
28e5dec8
JH
2144 (void)SvIOKp_on(sv); /* Must do this first, to clear any SvOOK */
2145 /* < not <= as for NV doesn't preserve UV, ((NV)IV_MAX+1) will almost
2146 certainly cast into the IV range at IV_MAX, whereas the correct
2147 answer is the UV IV_MAX +1. Hence < ensures that dodgy boundary
2148 cases go to UV */
e91de695
JH
2149#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
2150 if (Perl_isnan(SvNVX(sv))) {
2151 SvUV_set(sv, 0);
2152 SvIsUV_on(sv);
2153 return FALSE;
2154 }
2155#endif
28e5dec8 2156 if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
45977657 2157 SvIV_set(sv, I_V(SvNVX(sv)));
659c4b96 2158 if (SvNVX(sv) == (NV) SvIVX(sv)
28e5dec8 2159#ifndef NV_PRESERVES_UV
53e2bfb7 2160 && SvIVX(sv) != IV_MIN /* avoid negating IV_MIN below */
28e5dec8
JH
2161 && (((UV)1 << NV_PRESERVES_UV_BITS) >
2162 (UV)(SvIVX(sv) > 0 ? SvIVX(sv) : -SvIVX(sv)))
2163 /* Don't flag it as "accurately an integer" if the number
2164 came from a (by definition imprecise) NV operation, and
2165 we're outside the range of NV integer precision */
2166#endif
2167 ) {
a43d94f2
NC
2168 if (SvNOK(sv))
2169 SvIOK_on(sv); /* Can this go wrong with rounding? NWC */
2170 else {
2171 /* scalar has trailing garbage, eg "42a" */
2172 }
28e5dec8 2173 DEBUG_c(PerlIO_printf(Perl_debug_log,
147e3846 2174 "0x%" UVxf " iv(%" NVgf " => %" IVdf ") (precise)\n",
28e5dec8
JH
2175 PTR2UV(sv),
2176 SvNVX(sv),
2177 SvIVX(sv)));
2178
2179 } else {
2180 /* IV not precise. No need to convert from PV, as NV
2181 conversion would already have cached IV if it detected
2182 that PV->IV would be better than PV->NV->IV
2183 flags already correct - don't set public IOK. */
2184 DEBUG_c(PerlIO_printf(Perl_debug_log,
147e3846 2185 "0x%" UVxf " iv(%" NVgf " => %" IVdf ") (imprecise)\n",
28e5dec8
JH
2186 PTR2UV(sv),
2187 SvNVX(sv),
2188 SvIVX(sv)));
2189 }
2190 /* Can the above go wrong if SvIVX == IV_MIN and SvNVX < IV_MIN,
2191 but the cast (NV)IV_MIN rounds to a the value less (more
2192 negative) than IV_MIN which happens to be equal to SvNVX ??
2193 Analogous to 0xFFFFFFFFFFFFFFFF rounding up to NV (2**64) and
2194 NV rounding back to 0xFFFFFFFFFFFFFFFF, so UVX == UV(NVX) and
2195 (NV)UVX == NVX are both true, but the values differ. :-(
2196 Hopefully for 2s complement IV_MIN is something like
2197 0x8000000000000000 which will be exact. NWC */
d460ef45 2198 }
25da4f38 2199 else {
607fa7f2 2200 SvUV_set(sv, U_V(SvNVX(sv)));
28e5dec8 2201 if (
659c4b96 2202 (SvNVX(sv) == (NV) SvUVX(sv))
28e5dec8
JH
2203#ifndef NV_PRESERVES_UV
2204 /* Make sure it's not 0xFFFFFFFFFFFFFFFF */
2205 /*&& (SvUVX(sv) != UV_MAX) irrelevant with code below */
2206 && (((UV)1 << NV_PRESERVES_UV_BITS) > SvUVX(sv))
2207 /* Don't flag it as "accurately an integer" if the number
2208 came from a (by definition imprecise) NV operation, and
2209 we're outside the range of NV integer precision */
2210#endif
a43d94f2 2211 && SvNOK(sv)
28e5dec8
JH
2212 )
2213 SvIOK_on(sv);
25da4f38 2214 SvIsUV_on(sv);
1c846c1f 2215 DEBUG_c(PerlIO_printf(Perl_debug_log,
147e3846 2216 "0x%" UVxf " 2iv(%" UVuf " => %" IVdf ") (as unsigned)\n",
56431972 2217 PTR2UV(sv),
57def98f
JH
2218 SvUVX(sv),
2219 SvUVX(sv)));
25da4f38 2220 }
748a9306 2221 }
cd84013a 2222 else if (SvPOKp(sv)) {
c2988b20 2223 UV value;
80e5abf2
DM
2224 int numtype;
2225 const char *s = SvPVX_const(sv);
2226 const STRLEN cur = SvCUR(sv);
2227
2228 /* short-cut for a single digit string like "1" */
2229
2230 if (cur == 1) {
2231 char c = *s;
2232 if (isDIGIT(c)) {
2233 if (SvTYPE(sv) < SVt_PVIV)
2234 sv_upgrade(sv, SVt_PVIV);
2235 (void)SvIOK_on(sv);
2236 SvIV_set(sv, (IV)(c - '0'));
2237 return FALSE;
2238 }
2239 }
2240
2241 numtype = grok_number(s, cur, &value);
af359546 2242 /* We want to avoid a possible problem when we cache an IV/ a UV which
25da4f38 2243 may be later translated to an NV, and the resulting NV is not
c2988b20
NC
2244 the same as the direct translation of the initial string
2245 (eg 123.456 can shortcut to the IV 123 with atol(), but we must
2246 be careful to ensure that the value with the .456 is around if the
2247 NV value is requested in the future).
1c846c1f 2248
af359546 2249 This means that if we cache such an IV/a UV, we need to cache the
25da4f38 2250 NV as well. Moreover, we trade speed for space, and do not
28e5dec8 2251 cache the NV if we are sure it's not needed.
25da4f38 2252 */
16b7a9a4 2253
c2988b20
NC
2254 /* SVt_PVNV is one higher than SVt_PVIV, hence this order */
2255 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2256 == IS_NUMBER_IN_UV) {
5e045b90 2257 /* It's definitely an integer, only upgrade to PVIV */
28e5dec8
JH
2258 if (SvTYPE(sv) < SVt_PVIV)
2259 sv_upgrade(sv, SVt_PVIV);
f7bbb42a 2260 (void)SvIOK_on(sv);
c2988b20
NC
2261 } else if (SvTYPE(sv) < SVt_PVNV)
2262 sv_upgrade(sv, SVt_PVNV);
28e5dec8 2263
a13f4dff 2264 if ((numtype & (IS_NUMBER_INFINITY | IS_NUMBER_NAN))) {
75a57a38 2265 if (ckWARN(WARN_NUMERIC) && ((numtype & IS_NUMBER_TRAILING)))
6b322424 2266 not_a_number(sv);
3823048b 2267 S_sv_setnv(aTHX_ sv, numtype);
a13f4dff
JH
2268 return FALSE;
2269 }
2270
f2524eef 2271 /* If NVs preserve UVs then we only use the UV value if we know that
c2988b20
NC
2272 we aren't going to call atof() below. If NVs don't preserve UVs
2273 then the value returned may have more precision than atof() will
2274 return, even though value isn't perfectly accurate. */
2275 if ((numtype & (IS_NUMBER_IN_UV
2276#ifdef NV_PRESERVES_UV
2277 | IS_NUMBER_NOT_INT
2278#endif
2279 )) == IS_NUMBER_IN_UV) {
2280 /* This won't turn off the public IOK flag if it was set above */
2281 (void)SvIOKp_on(sv);
2282
2283 if (!(numtype & IS_NUMBER_NEG)) {
2284 /* positive */;
2285 if (value <= (UV)IV_MAX) {
45977657 2286 SvIV_set(sv, (IV)value);
c2988b20 2287 } else {
af359546 2288 /* it didn't overflow, and it was positive. */
607fa7f2 2289 SvUV_set(sv, value);
c2988b20
NC
2290 SvIsUV_on(sv);
2291 }
2292 } else {
2293 /* 2s complement assumption */
2294 if (value <= (UV)IV_MIN) {
53e2bfb7
DM
2295 SvIV_set(sv, value == (UV)IV_MIN
2296 ? IV_MIN : -(IV)value);
c2988b20
NC
2297 } else {
2298 /* Too negative for an IV. This is a double upgrade, but
d1be9408 2299 I'm assuming it will be rare. */
c2988b20
NC
2300 if (SvTYPE(sv) < SVt_PVNV)
2301 sv_upgrade(sv, SVt_PVNV);
2302 SvNOK_on(sv);
2303 SvIOK_off(sv);
2304 SvIOKp_on(sv);
9d6ce603 2305 SvNV_set(sv, -(NV)value);
45977657 2306 SvIV_set(sv, IV_MIN);
c2988b20
NC
2307 }
2308 }
2309 }
2310 /* For !NV_PRESERVES_UV and IS_NUMBER_IN_UV and IS_NUMBER_NOT_INT we
2311 will be in the previous block to set the IV slot, and the next
2312 block to set the NV slot. So no else here. */
2313
2314 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2315 != IS_NUMBER_IN_UV) {
2316 /* It wasn't an (integer that doesn't overflow the UV). */
3823048b 2317 S_sv_setnv(aTHX_ sv, numtype);
28e5dec8 2318
c2988b20
NC
2319 if (! numtype && ckWARN(WARN_NUMERIC))
2320 not_a_number(sv);
28e5dec8 2321
147e3846 2322 DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2iv(%" NVgf ")\n",
c2988b20 2323 PTR2UV(sv), SvNVX(sv)));
28e5dec8 2324
28e5dec8 2325#ifdef NV_PRESERVES_UV
af359546
NC
2326 (void)SvIOKp_on(sv);
2327 (void)SvNOK_on(sv);
e91de695
JH
2328#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
2329 if (Perl_isnan(SvNVX(sv))) {
2330 SvUV_set(sv, 0);
2331 SvIsUV_on(sv);
2332 return FALSE;
2333 }
2334#endif
af359546
NC
2335 if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
2336 SvIV_set(sv, I_V(SvNVX(sv)));
2337 if ((NV)(SvIVX(sv)) == SvNVX(sv)) {
2338 SvIOK_on(sv);
2339 } else {
6f207bd3 2340 NOOP; /* Integer is imprecise. NOK, IOKp */
af359546
NC
2341 }
2342 /* UV will not work better than IV */
2343 } else {
2344 if (SvNVX(sv) > (NV)UV_MAX) {
2345 SvIsUV_on(sv);
2346 /* Integer is inaccurate. NOK, IOKp, is UV */
2347 SvUV_set(sv, UV_MAX);
af359546
NC
2348 } else {
2349 SvUV_set(sv, U_V(SvNVX(sv)));
2350 /* 0xFFFFFFFFFFFFFFFF not an issue in here, NVs
2351 NV preservse UV so can do correct comparison. */
2352 if ((NV)(SvUVX(sv)) == SvNVX(sv)) {
2353 SvIOK_on(sv);
af359546 2354 } else {
6f207bd3 2355 NOOP; /* Integer is imprecise. NOK, IOKp, is UV */
af359546
NC
2356 }
2357 }
4b0c9573 2358 SvIsUV_on(sv);
af359546 2359 }
28e5dec8 2360#else /* NV_PRESERVES_UV */
c2988b20
NC
2361 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2362 == (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT)) {
af359546 2363 /* The IV/UV slot will have been set from value returned by
c2988b20
NC
2364 grok_number above. The NV slot has just been set using
2365 Atof. */
560b0c46 2366 SvNOK_on(sv);
c2988b20
NC
2367 assert (SvIOKp(sv));
2368 } else {
2369 if (((UV)1 << NV_PRESERVES_UV_BITS) >
2370 U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))) {
2371 /* Small enough to preserve all bits. */
2372 (void)SvIOKp_on(sv);
2373 SvNOK_on(sv);
45977657 2374 SvIV_set(sv, I_V(SvNVX(sv)));
659c4b96 2375 if ((NV)(SvIVX(sv)) == SvNVX(sv))
c2988b20
NC
2376 SvIOK_on(sv);
2377 /* Assumption: first non-preserved integer is < IV_MAX,
2378 this NV is in the preserved range, therefore: */
2379 if (!(U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))
2380 < (UV)IV_MAX)) {
147e3846 2381 Perl_croak(aTHX_ "sv_2iv assumed (U_V(fabs((double)SvNVX(sv))) < (UV)IV_MAX) but SvNVX(sv)=%" NVgf " U_V is 0x%" UVxf ", IV_MAX is 0x%" UVxf "\n", SvNVX(sv), U_V(SvNVX(sv)), (UV)IV_MAX);
c2988b20
NC
2382 }
2383 } else {
2384 /* IN_UV NOT_INT
2385 0 0 already failed to read UV.
2386 0 1 already failed to read UV.
2387 1 0 you won't get here in this case. IV/UV
2388 slot set, public IOK, Atof() unneeded.
2389 1 1 already read UV.
2390 so there's no point in sv_2iuv_non_preserve() attempting
2391 to use atol, strtol, strtoul etc. */
47031da6 2392# ifdef DEBUGGING
40a17c4c 2393 sv_2iuv_non_preserve (sv, numtype);
47031da6
NC
2394# else
2395 sv_2iuv_non_preserve (sv);
2396# endif
c2988b20
NC
2397 }
2398 }
28e5dec8 2399#endif /* NV_PRESERVES_UV */
a43d94f2
NC
2400 /* It might be more code efficient to go through the entire logic above
2401 and conditionally set with SvIOKp_on() rather than SvIOK(), but it
2402 gets complex and potentially buggy, so more programmer efficient
2403 to do it this way, by turning off the public flags: */
2404 if (!numtype)
2405 SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK);
25da4f38 2406 }
af359546
NC
2407 }
2408 else {
675c862f 2409 if (isGV_with_GP(sv))
159b6efe 2410 return glob_2number(MUTABLE_GV(sv));
180488f8 2411
4f62cd62 2412 if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
af359546 2413 report_uninit(sv);
25da4f38
IZ
2414 if (SvTYPE(sv) < SVt_IV)
2415 /* Typically the caller expects that sv_any is not NULL now. */
2416 sv_upgrade(sv, SVt_IV);
af359546
NC
2417 /* Return 0 from the caller. */
2418 return TRUE;
2419 }
2420 return FALSE;
2421}
2422
2423/*
2424=for apidoc sv_2iv_flags
2425
2426Return the integer value of an SV, doing any necessary string
c5608a1f 2427conversion. If C<flags> has the C<SV_GMAGIC> bit set, does an C<mg_get()> first.
af359546
NC
2428Normally used via the C<SvIV(sv)> and C<SvIVx(sv)> macros.
2429
2430=cut
2431*/
2432
2433IV
5aaab254 2434Perl_sv_2iv_flags(pTHX_ SV *const sv, const I32 flags)
af359546 2435{
1061065f 2436 PERL_ARGS_ASSERT_SV_2IV_FLAGS;
4bac9ae4 2437
217f6fa3
FC
2438 assert (SvTYPE(sv) != SVt_PVAV && SvTYPE(sv) != SVt_PVHV
2439 && SvTYPE(sv) != SVt_PVFM);
2440
4bac9ae4
CS
2441 if (SvGMAGICAL(sv) && (flags & SV_GMAGIC))
2442 mg_get(sv);
2443
2444 if (SvROK(sv)) {
2445 if (SvAMAGIC(sv)) {
2446 SV * tmpstr;
2447 if (flags & SV_SKIP_OVERLOAD)
2448 return 0;
2449 tmpstr = AMG_CALLunary(sv, numer_amg);
2450 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2451 return SvIV(tmpstr);
2452 }
2453 }
2454 return PTR2IV(SvRV(sv));
2455 }
2456
8d919b0a 2457 if (SvVALID(sv) || isREGEXP(sv)) {
4e8879f3
DM
2458 /* FBMs use the space for SvIVX and SvNVX for other purposes, so
2459 must not let them cache IVs.
2b2b6d6d
NC
2460 In practice they are extremely unlikely to actually get anywhere
2461 accessible by user Perl code - the only way that I'm aware of is when
2462 a constant subroutine which is used as the second argument to index.
cd84013a
FC
2463
2464 Regexps have no SvIVX and SvNVX fields.
2b2b6d6d 2465 */
8d919b0a 2466 assert(isREGEXP(sv) || SvPOKp(sv));
e20b6c3b 2467 {
71c558c3 2468 UV value;
8d919b0a
FC
2469 const char * const ptr =
2470 isREGEXP(sv) ? RX_WRAPPED((REGEXP*)sv) : SvPVX_const(sv);
e91de695
JH
2471 const int numtype
2472 = grok_number(ptr, SvCUR(sv), &value);
71c558c3
NC
2473
2474 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2475 == IS_NUMBER_IN_UV) {
2476 /* It's definitely an integer */
2477 if (numtype & IS_NUMBER_NEG) {
2478 if (value < (UV)IV_MIN)
2479 return -(IV)value;
2480 } else {
2481 if (value < (UV)IV_MAX)
2482 return (IV)value;
2483 }
2484 }
058b8ae2 2485
e91de695
JH
2486 /* Quite wrong but no good choices. */
2487 if ((numtype & IS_NUMBER_INFINITY)) {
2488 return (numtype & IS_NUMBER_NEG) ? IV_MIN : IV_MAX;
2489 } else if ((numtype & IS_NUMBER_NAN)) {
2490 return 0; /* So wrong. */
2491 }
2492
71c558c3
NC
2493 if (!numtype) {
2494 if (ckWARN(WARN_NUMERIC))
2495 not_a_number(sv);
2496 }
8d919b0a 2497 return I_V(Atof(ptr));
e20b6c3b 2498 }
4bac9ae4
CS
2499 }
2500
2501 if (SvTHINKFIRST(sv)) {
af359546
NC
2502 if (SvREADONLY(sv) && !SvOK(sv)) {
2503 if (ckWARN(WARN_UNINITIALIZED))
2504 report_uninit(sv);
2505 return 0;
2506 }
2507 }
4bac9ae4 2508
af359546
NC
2509 if (!SvIOKp(sv)) {
2510 if (S_sv_2iuv_common(aTHX_ sv))
2511 return 0;
79072805 2512 }
4bac9ae4 2513
147e3846 2514 DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2iv(%" IVdf ")\n",
1d7c1841 2515 PTR2UV(sv),SvIVX(sv)));
25da4f38 2516 return SvIsUV(sv) ? (IV)SvUVX(sv) : SvIVX(sv);
79072805
LW
2517}
2518
645c22ef 2519/*
891f9566 2520=for apidoc sv_2uv_flags
645c22ef
DM
2521
2522Return the unsigned integer value of an SV, doing any necessary string
c5608a1f 2523conversion. If C<flags> has the C<SV_GMAGIC> bit set, does an C<mg_get()> first.
891f9566 2524Normally used via the C<SvUV(sv)> and C<SvUVx(sv)> macros.
645c22ef
DM
2525
2526=cut
2527*/
2528
ff68c719 2529UV
5aaab254 2530Perl_sv_2uv_flags(pTHX_ SV *const sv, const I32 flags)
ff68c719 2531{
1061065f 2532 PERL_ARGS_ASSERT_SV_2UV_FLAGS;
4bac9ae4
CS
2533
2534 if (SvGMAGICAL(sv) && (flags & SV_GMAGIC))
2535 mg_get(sv);
2536
2537 if (SvROK(sv)) {
2538 if (SvAMAGIC(sv)) {
2539 SV *tmpstr;
2540 if (flags & SV_SKIP_OVERLOAD)
2541 return 0;
2542 tmpstr = AMG_CALLunary(sv, numer_amg);
2543 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2544 return SvUV(tmpstr);
2545 }
2546 }
2547 return PTR2UV(SvRV(sv));
2548 }
2549
8d919b0a 2550 if (SvVALID(sv) || isREGEXP(sv)) {
2b2b6d6d 2551 /* FBMs use the space for SvIVX and SvNVX for other purposes, and use
cd84013a
FC
2552 the same flag bit as SVf_IVisUV, so must not let them cache IVs.
2553 Regexps have no SvIVX and SvNVX fields. */
8d919b0a 2554 assert(isREGEXP(sv) || SvPOKp(sv));
e20b6c3b 2555 {
71c558c3 2556 UV value;
8d919b0a
FC
2557 const char * const ptr =
2558 isREGEXP(sv) ? RX_WRAPPED((REGEXP*)sv) : SvPVX_const(sv);
e91de695
JH
2559 const int numtype
2560 = grok_number(ptr, SvCUR(sv), &value);
71c558c3
NC
2561
2562 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2563 == IS_NUMBER_IN_UV) {
2564 /* It's definitely an integer */
2565 if (!(numtype & IS_NUMBER_NEG))
2566 return value;
2567 }
058b8ae2 2568
e91de695
JH
2569 /* Quite wrong but no good choices. */
2570 if ((numtype & IS_NUMBER_INFINITY)) {
2571 return UV_MAX; /* So wrong. */
2572 } else if ((numtype & IS_NUMBER_NAN)) {
2573 return 0; /* So wrong. */
2574 }
2575
71c558c3
NC
2576 if (!numtype) {
2577 if (ckWARN(WARN_NUMERIC))
2578 not_a_number(sv);
2579 }
8d919b0a 2580 return U_V(Atof(ptr));
e20b6c3b 2581 }
4bac9ae4
CS
2582 }
2583
2584 if (SvTHINKFIRST(sv)) {
0336b60e 2585 if (SvREADONLY(sv) && !SvOK(sv)) {
0336b60e 2586 if (ckWARN(WARN_UNINITIALIZED))
29489e7c 2587 report_uninit(sv);
ff68c719
PP
2588 return 0;
2589 }
2590 }
4bac9ae4 2591
af359546
NC
2592 if (!SvIOKp(sv)) {
2593 if (S_sv_2iuv_common(aTHX_ sv))
2594 return 0;
ff68c719 2595 }
25da4f38 2596
147e3846 2597 DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2uv(%" UVuf ")\n",
1d7c1841 2598 PTR2UV(sv),SvUVX(sv)));
25da4f38 2599 return SvIsUV(sv) ? SvUVX(sv) : (UV)SvIVX(sv);
ff68c719
PP
2600}
2601
645c22ef 2602/*
196007d1 2603=for apidoc sv_2nv_flags
645c22ef
DM
2604
2605Return the num value of an SV, doing any necessary string or integer
c5608a1f 2606conversion. If C<flags> has the C<SV_GMAGIC> bit set, does an C<mg_get()> first.
39d5de13 2607Normally used via the C<SvNV(sv)> and C<SvNVx(sv)> macros.
645c22ef
DM
2608
2609=cut
2610*/
2611
65202027 2612NV
5aaab254 2613Perl_sv_2nv_flags(pTHX_ SV *const sv, const I32 flags)
79072805 2614{
1061065f
DD
2615 PERL_ARGS_ASSERT_SV_2NV_FLAGS;
2616
217f6fa3
FC
2617 assert (SvTYPE(sv) != SVt_PVAV && SvTYPE(sv) != SVt_PVHV
2618 && SvTYPE(sv) != SVt_PVFM);
8d919b0a 2619 if (SvGMAGICAL(sv) || SvVALID(sv) || isREGEXP(sv)) {
2b2b6d6d 2620 /* FBMs use the space for SvIVX and SvNVX for other purposes, and use
cd84013a
FC
2621 the same flag bit as SVf_IVisUV, so must not let them cache NVs.
2622 Regexps have no SvIVX and SvNVX fields. */
8d919b0a 2623 const char *ptr;
39d5de13
DM
2624 if (flags & SV_GMAGIC)
2625 mg_get(sv);
463ee0b2
LW
2626 if (SvNOKp(sv))
2627 return SvNVX(sv);
cd84013a 2628 if (SvPOKp(sv) && !SvIOKp(sv)) {
8d919b0a
FC
2629 ptr = SvPVX_const(sv);
2630 grokpv:
041457d9 2631 if (!SvIOKp(sv) && ckWARN(WARN_NUMERIC) &&
8d919b0a 2632 !grok_number(ptr, SvCUR(sv), NULL))
a0d0e21e 2633 not_a_number(sv);
8d919b0a 2634 return Atof(ptr);
a0d0e21e 2635 }
25da4f38 2636 if (SvIOKp(sv)) {
1c846c1f 2637 if (SvIsUV(sv))
65202027 2638 return (NV)SvUVX(sv);
25da4f38 2639 else
65202027 2640 return (NV)SvIVX(sv);
47a72cb8
NC
2641 }
2642 if (SvROK(sv)) {
2643 goto return_rok;
2644 }
8d919b0a
FC
2645 if (isREGEXP(sv)) {
2646 ptr = RX_WRAPPED((REGEXP *)sv);
2647 goto grokpv;
2648 }
47a72cb8
NC
2649 assert(SvTYPE(sv) >= SVt_PVMG);
2650 /* This falls through to the report_uninit near the end of the
2651 function. */
2652 } else if (SvTHINKFIRST(sv)) {
a0d0e21e 2653 if (SvROK(sv)) {
47a72cb8 2654 return_rok:
deb46114 2655 if (SvAMAGIC(sv)) {
aee036bb
DM
2656 SV *tmpstr;
2657 if (flags & SV_SKIP_OVERLOAD)
2658 return 0;
31d632c3 2659 tmpstr = AMG_CALLunary(sv, numer_amg);
deb46114
NC
2660 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2661 return SvNV(tmpstr);
2662 }
2663 }
2664 return PTR2NV(SvRV(sv));
a0d0e21e 2665 }
0336b60e 2666 if (SvREADONLY(sv) && !SvOK(sv)) {
599cee73 2667 if (ckWARN(WARN_UNINITIALIZED))
29489e7c 2668 report_uninit(sv);
ed6116ce
LW
2669 return 0.0;
2670 }
79072805
LW
2671 }
2672 if (SvTYPE(sv) < SVt_NV) {
7e25a7e9
NC
2673 /* The logic to use SVt_PVNV if necessary is in sv_upgrade. */
2674 sv_upgrade(sv, SVt_NV);
097ee67d 2675 DEBUG_c({
f93f4e46 2676 STORE_NUMERIC_LOCAL_SET_STANDARD();
1d7c1841 2677 PerlIO_printf(Perl_debug_log,
147e3846 2678 "0x%" UVxf " num(%" NVgf ")\n",
1d7c1841 2679 PTR2UV(sv), SvNVX(sv));
097ee67d
JH
2680 RESTORE_NUMERIC_LOCAL();
2681 });
79072805
LW
2682 }
2683 else if (SvTYPE(sv) < SVt_PVNV)
2684 sv_upgrade(sv, SVt_PVNV);
59d8ce62
NC
2685 if (SvNOKp(sv)) {
2686 return SvNVX(sv);
61604483 2687 }
59d8ce62 2688 if (SvIOKp(sv)) {
9d6ce603 2689 SvNV_set(sv, SvIsUV(sv) ? (NV)SvUVX(sv) : (NV)SvIVX(sv));
28e5dec8 2690#ifdef NV_PRESERVES_UV
a43d94f2
NC
2691 if (SvIOK(sv))
2692 SvNOK_on(sv);
2693 else
2694 SvNOKp_on(sv);
28e5dec8
JH
2695#else
2696 /* Only set the public NV OK flag if this NV preserves the IV */
2697 /* Check it's not 0xFFFFFFFFFFFFFFFF */
a43d94f2
NC
2698 if (SvIOK(sv) &&
2699 SvIsUV(sv) ? ((SvUVX(sv) != UV_MAX)&&(SvUVX(sv) == U_V(SvNVX(sv))))
28e5dec8
JH
2700 : (SvIVX(sv) == I_V(SvNVX(sv))))
2701 SvNOK_on(sv);
2702 else
2703 SvNOKp_on(sv);
2704#endif
93a17b20 2705 }
cd84013a 2706 else if (SvPOKp(sv)) {
c2988b20 2707 UV value;
3823048b 2708 const int numtype = grok_number(SvPVX_const(sv), SvCUR(sv), &value);
041457d9 2709 if (!SvIOKp(sv) && !numtype && ckWARN(WARN_NUMERIC))
a0d0e21e 2710 not_a_number(sv);
28e5dec8 2711#ifdef NV_PRESERVES_UV
c2988b20
NC
2712 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2713 == IS_NUMBER_IN_UV) {
5e045b90 2714 /* It's definitely an integer */
9d6ce603 2715 SvNV_set(sv, (numtype & IS_NUMBER_NEG) ? -(NV)value : (NV)value);
66d83377 2716 } else {
3823048b 2717 S_sv_setnv(aTHX_ sv, numtype);
66d83377 2718 }
a43d94f2
NC
2719 if (numtype)
2720 SvNOK_on(sv);
2721 else
2722 SvNOKp_on(sv);
28e5dec8 2723#else
e91de695
JH
2724 SvNV_set(sv, Atof(SvPVX_const(sv)));
2725 /* Only set the public NV OK flag if this NV preserves the value in
2726 the PV at least as well as an IV/UV would.
2727 Not sure how to do this 100% reliably. */
2728 /* if that shift count is out of range then Configure's test is
2729 wonky. We shouldn't be in here with NV_PRESERVES_UV_BITS ==
2730 UV_BITS */
2731 if (((UV)1 << NV_PRESERVES_UV_BITS) >
2732 U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))) {
2733 SvNOK_on(sv); /* Definitely small enough to preserve all bits */
2734 } else if (!(numtype & IS_NUMBER_IN_UV)) {
2735 /* Can't use strtol etc to convert this string, so don't try.
2736 sv_2iv and sv_2uv will use the NV to convert, not the PV. */
c2988b20
NC
2737 SvNOK_on(sv);
2738 } else {
e91de695 2739 /* value has been set. It may not be precise. */
53e2bfb7 2740 if ((numtype & IS_NUMBER_NEG) && (value >= (UV)IV_MIN)) {
e91de695
JH
2741 /* 2s complement assumption for (UV)IV_MIN */
2742 SvNOK_on(sv); /* Integer is too negative. */
c2988b20 2743 } else {
e91de695
JH
2744 SvNOKp_on(sv);
2745 SvIOKp_on(sv);
6fa402ec 2746
e91de695 2747 if (numtype & IS_NUMBER_NEG) {
02b08bbc
DM
2748 /* -IV_MIN is undefined, but we should never reach
2749 * this point with both IS_NUMBER_NEG and value ==
2750 * (UV)IV_MIN */
2751 assert(value != (UV)IV_MIN);
e91de695
JH
2752 SvIV_set(sv, -(IV)value);
2753 } else if (value <= (UV)IV_MAX) {
2754 SvIV_set(sv, (IV)value);
2755 } else {
2756 SvUV_set(sv, value);
2757 SvIsUV_on(sv);
2758 }
c2988b20 2759
e91de695
JH
2760 if (numtype & IS_NUMBER_NOT_INT) {
2761 /* I believe that even if the original PV had decimals,
2762 they are lost beyond the limit of the FP precision.
2763 However, neither is canonical, so both only get p
2764 flags. NWC, 2000/11/25 */
2765 /* Both already have p flags, so do nothing */
2766 } else {
2767 const NV nv = SvNVX(sv);
2768 /* XXX should this spot have NAN_COMPARE_BROKEN, too? */
2769 if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
2770 if (SvIVX(sv) == I_V(nv)) {
2771 SvNOK_on(sv);
2772 } else {
2773 /* It had no "." so it must be integer. */
2774 }
2775 SvIOK_on(sv);
0f83c5a4 2776 } else {
e91de695
JH
2777 /* between IV_MAX and NV(UV_MAX).
2778 Could be slightly > UV_MAX */
2779
2780 if (numtype & IS_NUMBER_NOT_INT) {
2781 /* UV and NV both imprecise. */
0f83c5a4 2782 } else {
e91de695
JH
2783 const UV nv_as_uv = U_V(nv);
2784
2785 if (value == nv_as_uv && SvUVX(sv) != UV_MAX) {
2786 SvNOK_on(sv);
c2988b20 2787 }
e91de695 2788 SvIOK_on(sv);
c2988b20
NC
2789 }
2790 }
2791 }
2792 }
0f83c5a4 2793 }
e91de695
JH
2794 /* It might be more code efficient to go through the entire logic above
2795 and conditionally set with SvNOKp_on() rather than SvNOK(), but it
2796 gets complex and potentially buggy, so more programmer efficient
2797 to do it this way, by turning off the public flags: */
2798 if (!numtype)
2799 SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK);
28e5dec8 2800#endif /* NV_PRESERVES_UV */
93a17b20 2801 }
79072805 2802 else {
e91de695
JH
2803 if (isGV_with_GP(sv)) {
2804 glob_2number(MUTABLE_GV(sv));
2805 return 0.0;
2806 }
180488f8 2807
e91de695
JH
2808 if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
2809 report_uninit(sv);
2810 assert (SvTYPE(sv) >= SVt_NV);
2811 /* Typically the caller expects that sv_any is not NULL now. */
2812 /* XXX Ilya implies that this is a bug in callers that assume this
2813 and ideally should be fixed. */
2814 return 0.0;
79072805 2815 }
097ee67d 2816 DEBUG_c({
e91de695 2817 STORE_NUMERIC_LOCAL_SET_STANDARD();
147e3846 2818 PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2nv(%" NVgf ")\n",
e91de695
JH
2819 PTR2UV(sv), SvNVX(sv));
2820 RESTORE_NUMERIC_LOCAL();
2821 });
463ee0b2 2822 return SvNVX(sv);
79072805
LW
2823}
2824
800401ee
JH
2825/*
2826=for apidoc sv_2num
2827
2828Return an SV with the numeric value of the source SV, doing any necessary
d024d1a7
FC
2829reference or overload conversion. The caller is expected to have handled
2830get-magic already.
800401ee
JH
2831
2832=cut
2833*/
2834
2835SV *
5aaab254 2836Perl_sv_2num(pTHX_ SV *const sv)
800401ee 2837{
7918f24d
NC
2838 PERL_ARGS_ASSERT_SV_2NUM;
2839
b9ee0594
RGS
2840 if (!SvROK(sv))
2841 return sv;
800401ee 2842 if (SvAMAGIC(sv)) {
31d632c3 2843 SV * const tmpsv = AMG_CALLunary(sv, numer_amg);
a02ec77a 2844 TAINT_IF(tmpsv && SvTAINTED(tmpsv));
800401ee
JH
2845 if (tmpsv && (!SvROK(tmpsv) || (SvRV(tmpsv) != SvRV(sv))))
2846 return sv_2num(tmpsv);
2847 }
2848 return sv_2mortal(newSVuv(PTR2UV(SvRV(sv))));
2849}
2850
645c22ef
DM
2851/* uiv_2buf(): private routine for use by sv_2pv_flags(): print an IV or
2852 * UV as a string towards the end of buf, and return pointers to start and
2853 * end of it.
2854 *
2855 * We assume that buf is at least TYPE_CHARS(UV) long.
2856 */
2857
864dbfa3 2858static char *
5de3775c 2859S_uiv_2buf(char *const buf, const IV iv, UV uv, const int is_uv, char **const peob)
25da4f38 2860{
25da4f38 2861 char *ptr = buf + TYPE_CHARS(UV);
823a54a3 2862 char * const ebuf = ptr;
25da4f38 2863 int sign;
25da4f38 2864
7918f24d
NC
2865 PERL_ARGS_ASSERT_UIV_2BUF;
2866
25da4f38
IZ
2867 if (is_uv)
2868 sign = 0;
2869 else if (iv >= 0) {
2870 uv = iv;
2871 sign = 0;
2872 } else {
53e2bfb7 2873 uv = (iv == IV_MIN) ? (UV)iv : (UV)(-iv);
25da4f38
IZ
2874 sign = 1;
2875 }
2876 do {
eb160463 2877 *--ptr = '0' + (char)(uv % 10);
25da4f38
IZ
2878 } while (uv /= 10);
2879 if (sign)
2880 *--ptr = '-';
2881 *peob = ebuf;
2882 return ptr;
2883}
2884
bfaa02d5
JH
2885/* Helper for sv_2pv_flags and sv_vcatpvfn_flags. If the NV is an
2886 * infinity or a not-a-number, writes the appropriate strings to the
2887 * buffer, including a zero byte. On success returns the written length,
3bde2d43
JH
2888 * excluding the zero byte, on failure (not an infinity, not a nan)
2889 * returns zero, assert-fails on maxlen being too short.
3823048b
JH
2890 *
2891 * XXX for "Inf", "-Inf", and "NaN", we could have three read-only
2892 * shared string constants we point to, instead of generating a new
2893 * string for each instance. */
bfaa02d5 2894STATIC size_t
3823048b 2895S_infnan_2pv(NV nv, char* buffer, size_t maxlen, char plus) {
3bde2d43 2896 char* s = buffer;
bfaa02d5 2897 assert(maxlen >= 4);
3bde2d43
JH
2898 if (Perl_isinf(nv)) {
2899 if (nv < 0) {
2900 if (maxlen < 5) /* "-Inf\0" */
2901 return 0;
2902 *s++ = '-';
2903 } else if (plus) {
2904 *s++ = '+';
6e915616 2905 }
3bde2d43
JH
2906 *s++ = 'I';
2907 *s++ = 'n';
2908 *s++ = 'f';
2909 }
2910 else if (Perl_isnan(nv)) {
2911 *s++ = 'N';
2912 *s++ = 'a';
2913 *s++ = 'N';
2914 /* XXX optionally output the payload mantissa bits as
2915 * "(unsigned)" (to match the nan("...") C99 function,
2916 * or maybe as "(0xhhh...)" would make more sense...
2917 * provide a format string so that the user can decide?
2918 * NOTE: would affect the maxlen and assert() logic.*/
2919 }
2920 else {
2921 return 0;
bfaa02d5 2922 }
3bde2d43 2923 assert((s == buffer + 3) || (s == buffer + 4));
defe49c8
AL
2924 *s = 0;
2925 return s - buffer;
bfaa02d5
JH
2926}
2927
2928/*
2929=for apidoc sv_2pv_flags
2930
796b6530 2931Returns a pointer to the string value of an SV, and sets C<*lp> to its length.
c5608a1f 2932If flags has the C<SV_GMAGIC> bit set, does an C<mg_get()> first. Coerces C<sv> to a
bfaa02d5
JH
2933string if necessary. Normally invoked via the C<SvPV_flags> macro.
2934C<sv_2pv()> and C<sv_2pv_nomg> usually end up here too.
2935
2936=cut
2937*/
2938
2939char *
2940Perl_sv_2pv_flags(pTHX_ SV *const sv, STRLEN *const lp, const I32 flags)
2941{
2942 char *s;
2943
2944 PERL_ARGS_ASSERT_SV_2PV_FLAGS;
2945
2946 assert (SvTYPE(sv) != SVt_PVAV && SvTYPE(sv) != SVt_PVHV
2947 && SvTYPE(sv) != SVt_PVFM);
2948 if (SvGMAGICAL(sv) && (flags & SV_GMAGIC))
2949 mg_get(sv);
2950 if (SvROK(sv)) {
2951 if (SvAMAGIC(sv)) {
2952 SV *tmpstr;
2953 if (flags & SV_SKIP_OVERLOAD)
2954 return NULL;
2955 tmpstr = AMG_CALLunary(sv, string_amg);
2956 TAINT_IF(tmpstr && SvTAINTED(tmpstr));
2957 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2958 /* Unwrap this: */
2959 /* char *pv = lp ? SvPV(tmpstr, *lp) : SvPV_nolen(tmpstr);
2960 */
2961
2962 char *pv;
2963 if ((SvFLAGS(tmpstr) & (SVf_POK)) == SVf_POK) {
2964 if (flags & SV_CONST_RETURN) {
2965 pv = (char *) SvPVX_const(tmpstr);
2966 } else {
2967 pv = (flags & SV_MUTABLE_RETURN)
2968 ? SvPVX_mutable(tmpstr) : SvPVX(tmpstr);
2969 }
2970 if (lp)
2971 *lp = SvCUR(tmpstr);
2972 } else {
2973 pv = sv_2pv_flags(tmpstr, lp, flags);
2974 }
2975 if (SvUTF8(tmpstr))
2976 SvUTF8_on(sv);
2977 else
2978 SvUTF8_off(sv);
2979 return pv;
2980 }
2981 }
2982 {
2983 STRLEN len;
2984 char *retval;
2985 char *buffer;
2986 SV *const referent = SvRV(sv);
2987
2988 if (!referent) {
2989 len = 7;
2990 retval = buffer = savepvn("NULLREF", len);
2991 } else if (SvTYPE(referent) == SVt_REGEXP &&
2992 (!(PL_curcop->cop_hints & HINT_NO_AMAGIC) ||
2993 amagic_is_enabled(string_amg))) {
2994 REGEXP * const re = (REGEXP *)MUTABLE_PTR(referent);
2995
2996 assert(re);
2997
2998 /* If the regex is UTF-8 we want the containing scalar to
2999 have an UTF-8 flag too */
3000 if (RX_UTF8(re))
3001 SvUTF8_on(sv);
3002 else
3003 SvUTF8_off(sv);
3004
3005 if (lp)
3006 *lp = RX_WRAPLEN(re);
3007
3008 return RX_WRAPPED(re);
3009 } else {
3010 const char *const typestr = sv_reftype(referent, 0);
3011 const STRLEN typelen = strlen(typestr);
3012 UV addr = PTR2UV(referent);
3013 const char *stashname = NULL;
3014 STRLEN stashnamelen = 0; /* hush, gcc */
3015 const char *buffer_end;
3016
3017 if (SvOBJECT(referent)) {
3018 const HEK *const name = HvNAME_HEK(SvSTASH(referent));
3019
3020 if (name) {
3021 stashname = HEK_KEY(name);
3022 stashnamelen = HEK_LEN(name);
3023
3024 if (HEK_UTF8(name)) {
3025 SvUTF8_on(sv);
3026 } else {
3027 SvUTF8_off(sv);
3028 }
3029 } else {
3030 stashname = "__ANON__";
3031 stashnamelen = 8;
3032 }
3033 len = stashnamelen + 1 /* = */ + typelen + 3 /* (0x */
3034 + 2 * sizeof(UV) + 2 /* )\0 */;
3035 } else {
3036 len = typelen + 3 /* (0x */
3037 + 2 * sizeof(UV) + 2 /* )\0 */;
3038 }
fafee734 3039
4bac9ae4
CS
3040 Newx(buffer, len, char);
3041 buffer_end = retval = buffer + len;
3042
3043 /* Working backwards */
3044 *--retval = '\0';
3045 *--retval = ')';
3046 do {
3047 *--retval = PL_hexdigit[addr & 15];
3048 } while (addr >>= 4);
3049 *--retval = 'x';
3050 *--retval = '0';
3051 *--retval = '(';
3052
3053 retval -= typelen;
3054 memcpy(retval, typestr, typelen);
3055
3056 if (stashname) {
3057 *--retval = '=';
3058 retval -= stashnamelen;
3059 memcpy(retval, stashname, stashnamelen);
c080367d 3060 }
4bac9ae4
CS
3061 /* retval may not necessarily have reached the start of the
3062 buffer here. */
3063 assert (retval >= buffer);
3064
3065 len = buffer_end - retval - 1; /* -1 for that \0 */
463ee0b2 3066 }
cdb061a3 3067 if (lp)
4bac9ae4
CS
3068 *lp = len;
3069 SAVEFREEPV(buffer);
3070 return retval;
79072805 3071 }
79072805 3072 }
4bac9ae4
CS
3073
3074 if (SvPOKp(sv)) {
3075 if (lp)
3076 *lp = SvCUR(sv);
3077 if (flags & SV_MUTABLE_RETURN)
3078 return SvPVX_mutable(sv);
3079 if (flags & SV_CONST_RETURN)
3080 return (char *)SvPVX_const(sv);
3081 return SvPVX(sv);
3082 }
3083
3084 if (SvIOK(sv)) {
28e5dec8
JH
3085 /* I'm assuming that if both IV and NV are equally valid then
3086 converting the IV is going to be more efficient */
e1ec3a88 3087 const U32 isUIOK = SvIsUV(sv);
28e5dec8
JH
3088 char buf[TYPE_CHARS(UV)];
3089 char *ebuf, *ptr;
97a130b8 3090 STRLEN len;
28e5dec8
JH
3091
3092 if (SvTYPE(sv) < SVt_PVIV)
3093 sv_upgrade(sv, SVt_PVIV);
4ea1d550 3094 ptr = uiv_2buf(buf, SvIVX(sv), SvUVX(sv), isUIOK, &ebuf);
97a130b8 3095 len = ebuf - ptr;
5902b6a9 3096 /* inlined from sv_setpvn */
97a130b8
NC
3097 s = SvGROW_mutable(sv, len + 1);
3098 Move(ptr, s, len, char);
3099 s += len;
28e5dec8 3100 *s = '\0';
b127e37e 3101 SvPOK_on(sv);
28e5dec8 3102 }
4bac9ae4 3103 else if (SvNOK(sv)) {
79072805
LW
3104 if (SvTYPE(sv) < SVt_PVNV)
3105 sv_upgrade(sv, SVt_PVNV);
128eeacb
DD
3106 if (SvNVX(sv) == 0.0
3107#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
3108 && !Perl_isnan(SvNVX(sv))
3109#endif
3110 ) {
29912d93
NC
3111 s = SvGROW_mutable(sv, 2);
3112 *s++ = '0';
3113 *s = '\0';
3114 } else {
5e85836e 3115 STRLEN len;
fb8cdbc5 3116 STRLEN size = 5; /* "-Inf\0" */
0c7e610f 3117
fb8cdbc5 3118 s = SvGROW_mutable(sv, size);
3823048b 3119 len = S_infnan_2pv(SvNVX(sv), s, size, 0);
fb8cdbc5 3120 if (len > 0) {
0c7e610f 3121 s += len;
fb8cdbc5
JH
3122 SvPOK_on(sv);
3123 }
0c7e610f 3124 else {
0c7e610f 3125 /* some Xenix systems wipe out errno here */
fb8cdbc5
JH
3126 dSAVE_ERRNO;
3127
3840bff0
JH
3128 size =
3129 1 + /* sign */
3130 1 + /* "." */
3131 NV_DIG +
3132 1 + /* "e" */
3133 1 + /* sign */
3134 5 + /* exponent digits */
3135 1 + /* \0 */
3136 2; /* paranoia */
b127e37e 3137
fb8cdbc5 3138 s = SvGROW_mutable(sv, size);
b127e37e 3139#ifndef USE_LOCALE_NUMERIC
a4eca1d4
JH
3140 SNPRINTF_G(SvNVX(sv), s, SvLEN(sv), NV_DIG);
3141
0c7e610f
JH
3142 SvPOK_on(sv);
3143#else
28acfe03 3144 {
3840bff0 3145 bool local_radix;
67d796ae
KW
3146 DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
3147 STORE_LC_NUMERIC_SET_TO_NEEDED();
3840bff0 3148
3dbc6af5 3149 local_radix = PL_numeric_local && PL_numeric_radix_sv;
3840bff0
JH
3150 if (local_radix && SvLEN(PL_numeric_radix_sv) > 1) {
3151 size += SvLEN(PL_numeric_radix_sv) - 1;
3152 s = SvGROW_mutable(sv, size);
3153 }
3154
a4eca1d4 3155 SNPRINTF_G(SvNVX(sv), s, SvLEN(sv), NV_DIG);
0c7e610f
JH
3156
3157 /* If the radix character is UTF-8, and actually is in the
3158 * output, turn on the UTF-8 flag for the scalar */
3dbc6af5
KW
3159 if ( local_radix
3160 && SvUTF8(PL_numeric_radix_sv)
3161 && instr(s, SvPVX_const(PL_numeric_radix_sv)))
3162 {
3840bff0
JH
3163 SvUTF8_on(sv);
3164 }
3165
0c7e610f 3166 RESTORE_LC_NUMERIC();
28acfe03 3167 }
68e8f474 3168
0c7e610f
JH
3169 /* We don't call SvPOK_on(), because it may come to
3170 * pass that the locale changes so that the
3171 * stringification we just did is no longer correct. We
3172 * will have to re-stringify every time it is needed */
b127e37e 3173#endif
0c7e610f
JH
3174 RESTORE_ERRNO;
3175 }
3176 while (*s) s++;
bbce6d69 3177 }
79072805 3178 }
4bac9ae4
CS
3179 else if (isGV_with_GP(sv)) {
3180 GV *const gv = MUTABLE_GV(sv);
3181 SV *const buffer = sv_newmortal();
8d1c3e26 3182
4bac9ae4 3183 gv_efullname3(buffer, gv, "*");
180488f8 3184
4bac9ae4
CS
3185 assert(SvPOK(buffer));
3186 if (SvUTF8(buffer))
3187 SvUTF8_on(sv);
1097da16
TC
3188 else
3189 SvUTF8_off(sv);
4bac9ae4
CS
3190 if (lp)
3191 *lp = SvCUR(buffer);
3192 return SvPVX(buffer);
3193 }
8d919b0a
FC
3194 else if (isREGEXP(sv)) {
3195 if (lp) *lp = RX_WRAPLEN((REGEXP *)sv);
3196 return RX_WRAPPED((REGEXP *)sv);
3197 }
4bac9ae4 3198 else {
cdb061a3 3199 if (lp)
00b6aa41 3200 *lp = 0;
9f621bb0
NC
3201 if (flags & SV_UNDEF_RETURNS_NULL)
3202 return NULL;
4f62cd62 3203 if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
9f621bb0 3204 report_uninit(sv);
4bac9ae4
CS
3205 /* Typically the caller expects that sv_any is not NULL now. */
3206 if (!SvREADONLY(sv) && SvTYPE(sv) < SVt_PV)
25da4f38 3207 sv_upgrade(sv, SVt_PV);
73d840c0 3208 return (char *)"";
79072805 3209 }
4bac9ae4 3210
cdb061a3 3211 {
823a54a3 3212 const STRLEN len = s - SvPVX_const(sv);
cdb061a3
NC
3213 if (lp)
3214 *lp = len;
3215 SvCUR_set(sv, len);
3216 }
147e3846 3217 DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2pv(%s)\n",
3f7c398e 3218 PTR2UV(sv),SvPVX_const(sv)));
4d84ee25
NC
3219 if (flags & SV_CONST_RETURN)
3220 return (char *)SvPVX_const(sv);
10516c54
NC
3221 if (flags & SV_MUTABLE_RETURN)
3222 return SvPVX_mutable(sv);
463ee0b2
LW
3223 return SvPVX(sv);
3224}
3225
645c22ef 3226/*
6050d10e
JP
3227=for apidoc sv_copypv
3228
3229Copies a stringified representation of the source SV into the
796b6530 3230destination SV. Automatically performs any necessary C<mg_get> and
54f0641b 3231coercion of numeric values into strings. Guaranteed to preserve
796b6530
KW
3232C<UTF8> flag even from overloaded objects. Similar in nature to
3233C<sv_2pv[_flags]> but operates directly on an SV instead of just the
3234string. Mostly uses C<sv_2pv_flags> to do its work, except when that
6050d10e
JP
3235would lose the UTF-8'ness of the PV.
3236
4bac9ae4
CS
3237=for apidoc sv_copypv_nomg
3238
796b6530 3239Like C<sv_copypv>, but doesn't invoke get magic first.
4bac9ae4
CS
3240
3241=for apidoc sv_copypv_flags
3242
796b6530 3243Implementation of C<sv_copypv> and C<sv_copypv_nomg>. Calls get magic iff flags
c5608a1f 3244has the C<SV_GMAGIC> bit set.
4bac9ae4 3245
6050d10e
JP
3246=cut
3247*/
3248
3249void
5aaab254 3250Perl_sv_copypv_flags(pTHX_ SV *const dsv, SV *const ssv, const I32 flags)
4bac9ae4 3251{
446eaa42 3252 STRLEN len;
4bac9ae4 3253 const char *s;
7918f24d 3254
4bac9ae4 3255 PERL_ARGS_ASSERT_SV_COPYPV_FLAGS;
7918f24d 3256
c77ed9ca 3257 s = SvPV_flags_const(ssv,len,(flags & SV_GMAGIC));
cb50f42d 3258 sv_setpvn(dsv,s,len);
446eaa42 3259 if (SvUTF8(ssv))
cb50f42d 3260 SvUTF8_on(dsv);
446eaa42 3261 else
cb50f42d 3262 SvUTF8_off(dsv);
6050d10e
JP
3263}
3264
3265/*
645c22ef
DM
3266=for apidoc sv_2pvbyte
3267
796b6530 3268Return a pointer to the byte-encoded representation of the SV, and set C<*lp>
1e54db1a 3269to its length. May cause the SV to be downgraded from UTF-8 as a
645c22ef
DM
3270side-effect.
3271
3272Usually accessed via the C<SvPVbyte> macro.
3273
3274=cut
3275*/
3276
7340a771 3277char *
5aaab254 3278Perl_sv_2pvbyte(pTHX_ SV *sv, STRLEN *const lp)
7340a771 3279{
7918f24d
NC
3280 PERL_ARGS_ASSERT_SV_2PVBYTE;
3281
48120f8f 3282 SvGETMAGIC(sv);
4499db73
FC
3283 if (((SvREADONLY(sv) || SvFAKE(sv)) && !SvIsCOW(sv))
3284 || isGV_with_GP(sv) || SvROK(sv)) {
a901b181 3285 SV *sv2 = sv_newmortal();
48120f8f 3286 sv_copypv_nomg(sv2,sv);
a901b181
FC
3287 sv = sv2;
3288 }
0875d2fe 3289 sv_utf8_downgrade(sv,0);
71eb6d8c 3290 return lp ? SvPV_nomg(sv,*lp) : SvPV_nomg_nolen(sv);
7340a771
GS
3291}
3292
645c22ef 3293/*
035cbb0e
RGS
3294=for apidoc sv_2pvutf8
3295
796b6530 3296Return a pointer to the UTF-8-encoded representation of the SV, and set C<*lp>
035cbb0e
RGS
3297to its length. May cause the SV to be upgraded to UTF-8 as a side-effect.
3298
3299Usually accessed via the C<SvPVutf8> macro.
3300
3301=cut
3302*/
645c22ef 3303
7340a771 3304char *
5aaab254 3305Perl_sv_2pvutf8(pTHX_ SV *sv, STRLEN *const lp)
7340a771 3306{
7918f24d
NC
3307 PERL_ARGS_ASSERT_SV_2PVUTF8;
3308
4499db73
FC
3309 if (((SvREADONLY(sv) || SvFAKE(sv)) && !SvIsCOW(sv))
3310 || isGV_with_GP(sv) || SvROK(sv))
fe46cbda 3311 sv = sv_mortalcopy(sv);
4bac9ae4
CS
3312 else
3313 SvGETMAGIC(sv);
3314 sv_utf8_upgrade_nomg(sv);
c3ec315f 3315 return lp ? SvPV_nomg(sv,*lp) : SvPV_nomg_nolen(sv);
7340a771 3316}
1c846c1f 3317
7ee2227d 3318
645c22ef
DM
3319/*
3320=for apidoc sv_2bool
3321
796b6530
KW
3322This macro is only used by C<sv_true()> or its macro equivalent, and only if
3323the latter's argument is neither C<SvPOK>, C<SvIOK> nor C<SvNOK>.
3324It calls C<sv_2bool_flags> with the C<SV_GMAGIC> flag.
06c841cf
FC
3325
3326=for apidoc sv_2bool_flags
3327
796b6530
KW
3328This function is only used by C<sv_true()> and friends, and only if
3329the latter's argument is neither C<SvPOK>, C<SvIOK> nor C<SvNOK>. If the flags
3330contain C<SV_GMAGIC>, then it does an C<mg_get()> first.
06c841cf 3331
645c22ef
DM
3332
3333=cut
3334*/
3335
463ee0b2 3336bool
9d176cd8 3337Perl_sv_2bool_flags(pTHX_ SV *sv, I32 flags)
463ee0b2 3338{
06c841cf 3339 PERL_ARGS_ASSERT_SV_2BOOL_FLAGS;
7918f24d 3340
9d176cd8 3341 restart:
06c841cf 3342 if(flags & SV_GMAGIC) SvGETMAGIC(sv);
463ee0b2 3343
a0d0e21e
LW
3344 if (!SvOK(sv))
3345 return 0;
3346 if (SvROK(sv)) {
fabdb6c0 3347 if (SvAMAGIC(sv)) {
31d632c3 3348 SV * const tmpsv = AMG_CALLunary(sv, bool__amg);
9d176cd8
DD
3349 if (tmpsv && (!SvROK(tmpsv) || (SvRV(tmpsv) != SvRV(sv)))) {
3350 bool svb;
3351 sv = tmpsv;
3352 if(SvGMAGICAL(sv)) {
3353 flags = SV_GMAGIC;
3354 goto restart; /* call sv_2bool */
3355 }
3356 /* expanded SvTRUE_common(sv, (flags = 0, goto restart)) */
3357 else if(!SvOK(sv)) {
3358 svb = 0;
3359 }
3360 else if(SvPOK(sv)) {
3361 svb = SvPVXtrue(sv);
3362 }
3363 else if((SvFLAGS(sv) & (SVf_IOK|SVf_NOK))) {
3364 svb = (SvIOK(sv) && SvIVX(sv) != 0)
659c4b96 3365 || (SvNOK(sv) && SvNVX(sv) != 0.0);
9d176cd8
DD
3366 }
3367 else {
3368 flags = 0;
3369 goto restart; /* call sv_2bool_nomg */
3370 }
3371 return cBOOL(svb);
3372 }
fabdb6c0
AL
3373 }
3374 return SvRV(sv) != 0;
a0d0e21e 3375 }
85b7d9b3
FC
3376 if (isREGEXP(sv))
3377 return
3378 RX_WRAPLEN(sv) > 1 || (RX_WRAPLEN(sv) && *RX_WRAPPED(sv) != '0');
4bac9ae4 3379 return SvTRUE_common(sv, isGV_with_GP(sv) ? 1 : 0);
79072805
LW
3380}
3381
c461cf8f
JH
3382/*
3383=for apidoc sv_utf8_upgrade
3384
78ea37eb 3385Converts the PV of an SV to its UTF-8-encoded form.
645c22ef 3386Forces the SV to string form if it is not already.
2bbc8d55 3387Will C<mg_get> on C<sv> if appropriate.
796b6530 3388Always sets the C<SvUTF8> flag to avoid future validity checks even
2bbc8d55
SP
3389if the whole string is the same in UTF-8 as not.
3390Returns the number of bytes in the converted string
c461cf8f 3391
0efd0472 3392This is not a general purpose byte encoding to Unicode interface:
13a6c0e0
JH
3393use the Encode extension for that.
3394
fe749c9a
KW
3395=for apidoc sv_utf8_upgrade_nomg
3396
796b6530 3397Like C<sv_utf8_upgrade>, but doesn't do magic on C<sv>.
fe749c9a 3398
8d6d96c1
HS
3399=for apidoc sv_utf8_upgrade_flags
3400
78ea37eb 3401Converts the PV of an SV to its UTF-8-encoded form.
645c22ef 3402Forces the SV to string form if it is not already.
8d6d96c1 3403Always sets the SvUTF8 flag to avoid future validity checks even
960b0271
FC
3404if all the bytes are invariant in UTF-8.
3405If C<flags> has C<SV_GMAGIC> bit set,
2bbc8d55 3406will C<mg_get> on C<sv> if appropriate, else not.
2a590426 3407
796b6530 3408If C<flags> has C<SV_FORCE_UTF8_UPGRADE> set, this function assumes that the PV
2a590426
KW
3409will expand when converted to UTF-8, and skips the extra work of checking for
3410that. Typically this flag is used by a routine that has already parsed the
3411string and found such characters, and passes this information on so that the
3412work doesn't have to be repeated.
3413
3414Returns the number of bytes in the converted string.
8d6d96c1 3415
0efd0472 3416This is not a general purpose byte encoding to Unicode interface:
13a6c0e0
JH
3417use the Encode extension for that.
3418
2a590426 3419=for apidoc sv_utf8_upgrade_flags_grow
b3ab6785 3420
796b6530
KW
3421Like C<sv_utf8_upgrade_flags>, but has an additional parameter C<extra>, which is
3422the number of unused bytes the string of C<sv> is guaranteed to have free after
2a590426
KW
3423it upon return. This allows the caller to reserve extra space that it intends
3424to fill, to avoid extra grows.
b3ab6785 3425
2a590426
KW
3426C<sv_utf8_upgrade>, C<sv_utf8_upgrade_nomg>, and C<sv_utf8_upgrade_flags>
3427are implemented in terms of this function.
3428
3429Returns the number of bytes in the converted string (not including the spares).
3430
3431=cut
b3ab6785
KW
3432
3433(One might think that the calling routine could pass in the position of the
2a590426
KW
3434first variant character when it has set SV_FORCE_UTF8_UPGRADE, so it wouldn't
3435have to be found again. But that is not the case, because typically when the
3436caller is likely to use this flag, it won't be calling this routine unless it
3437finds something that won't fit into a byte. Otherwise it tries to not upgrade
3438and just use bytes. But some things that do fit into a byte are variants in
3439utf8, and the caller may not have been keeping track of these.)
b3ab6785 3440
6602b933
KW
3441If the routine itself changes the string, it adds a trailing C<NUL>. Such a
3442C<NUL> isn't guaranteed due to having other routines do the work in some input
3443cases, or if the input is already flagged as being in utf8.
b3ab6785
KW
3444
3445The speed of this could perhaps be improved for many cases if someone wanted to
3446write a fast function that counts the number of variant characters in a string,
3447especially if it could return the position of the first one.
3448
8d6d96c1
HS
3449*/
3450
3451STRLEN
5aaab254 3452Perl_sv_utf8_upgrade_flags_grow(pTHX_ SV *const sv, const I32 flags, STRLEN extra)
8d6d96c1 3453{
b3ab6785 3454 PERL_ARGS_ASSERT_SV_UTF8_UPGRADE_FLAGS_GROW;
7918f24d 3455
808c356f
RGS
3456 if (sv == &PL_sv_undef)
3457 return 0;
892f9127 3458 if (!SvPOK_nog(sv)) {
e0e62c2a 3459 STRLEN len = 0;
d52b7888
NC
3460 if (SvREADONLY(sv) && (SvPOKp(sv) || SvIOKp(sv) || SvNOKp(sv))) {
3461 (void) sv_2pv_flags(sv,&len, flags);
b3ab6785
KW
3462 if (SvUTF8(sv)) {
3463 if (extra) SvGROW(sv, SvCUR(sv) + extra);
d52b7888 3464 return len;
b3ab6785 3465 }
d52b7888 3466 } else {
33fb6f35 3467 (void) SvPV_force_flags(sv,len,flags & SV_GMAGIC);
d52b7888 3468 }
e0e62c2a 3469 }
4411f3b6 3470
f5cee72b 3471 if (SvUTF8(sv)) {
b3ab6785 3472 if (extra) SvGROW(sv, SvCUR(sv) + extra);
5fec3b1d 3473 return SvCUR(sv);
f5cee72b 3474 }
5fec3b1d 3475
765f542d 3476 if (SvIsCOW(sv)) {
c56ed9f6 3477 S_sv_uncow(aTHX_ sv, 0);
db42d148
NIS
3478 }
3479
4e93345f
KW
3480 if (SvCUR(sv) == 0) {
3481 if (extra) SvGROW(sv, extra);
3482 } else { /* Assume Latin-1/EBCDIC */
c4e7c712 3483 /* This function could be much more efficient if we
2bbc8d55 3484 * had a FLAG in SVs to signal if there are any variant
c4e7c712 3485 * chars in the PV. Given that there isn't such a flag
b3ab6785
KW
3486 * make the loop as fast as possible (although there are certainly ways
3487 * to speed this up, eg. through vectorization) */
3488 U8 * s = (U8 *) SvPVX_const(sv);
3489 U8 * e = (U8 *) SvEND(sv);
3490 U8 *t = s;
3491 STRLEN two_byte_count = 0;
c4e7c712 3492
b3ab6785
KW
3493 if (flags & SV_FORCE_UTF8_UPGRADE) goto must_be_utf8;
3494
3495 /* See if really will need to convert to utf8. We mustn't rely on our
3496 * incoming SV being well formed and having a trailing '\0', as certain
3497 * code in pp_formline can send us partially built SVs. */
3498
c4e7c712 3499 while (t < e) {
53c1dcc0 3500 const U8 ch = *t++;
6f2d5cbc 3501 if (NATIVE_BYTE_IS_INVARIANT(ch)) continue;
b3ab6785
KW
3502
3503 t--; /* t already incremented; re-point to first variant */
3504 two_byte_count = 1;
3505 goto must_be_utf8;
c4e7c712 3506 }
b3ab6785
KW
3507
3508 /* utf8 conversion not needed because all are invariants. Mark as
3509 * UTF-8 even if no variant - saves scanning loop */
c4e7c712 3510 SvUTF8_on(sv);
7f0bfbea 3511 if (extra) SvGROW(sv, SvCUR(sv) + extra);
b3ab6785
KW
3512 return SvCUR(sv);
3513
7b52d656 3514 must_be_utf8:
b3ab6785
KW
3515
3516 /* Here, the string should be converted to utf8, either because of an
3517 * input flag (two_byte_count = 0), or because a character that
3518 * requires 2 bytes was found (two_byte_count = 1). t points either to
3519 * the beginning of the string (if we didn't examine anything), or to
3520 * the first variant. In either case, everything from s to t - 1 will
3521 * occupy only 1 byte each on output.
3522 *
3523 * There are two main ways to convert. One is to create a new string
3524 * and go through the input starting from the beginning, appending each
3525 * converted value onto the new string as we go along. It's probably
3526 * best to allocate enough space in the string for the worst possible
3527 * case rather than possibly running out of space and having to
3528 * reallocate and then copy what we've done so far. Since everything
3529 * from s to t - 1 is invariant, the destination can be initialized
3530 * with these using a fast memory copy
3531 *
3532 * The other way is to figure out exactly how big the string should be
3533 * by parsing the entire input. Then you don't have to make it big
3534 * enough to handle the worst possible case, and more importantly, if
3535 * the string you already have is large enough, you don't have to
3536 * allocate a new string, you can copy the last character in the input
3537 * string to the final position(s) that will be occupied by the
3538 * converted string and go backwards, stopping at t, since everything
3539 * before that is invariant.
3540 *
3541 * There are advantages and disadvantages to each method.
3542 *
3543 * In the first method, we can allocate a new string, do the memory
3544 * copy from the s to t - 1, and then proceed through the rest of the
3545 * string byte-by-byte.
3546 *
3547 * In the second method, we proceed through the rest of the input
3548 * string just calculating how big the converted string will be. Then
3549 * there are two cases:
3550 * 1) if the string has enough extra space to handle the converted
3551 * value. We go backwards through the string, converting until we
3552 * get to the position we are at now, and then stop. If this
3553 * position is far enough along in the string, this method is
3554 * faster than the other method. If the memory copy were the same
3555 * speed as the byte-by-byte loop, that position would be about
3556 * half-way, as at the half-way mark, parsing to the end and back
3557 * is one complete string's parse, the same amount as starting
3558 * over and going all the way through. Actually, it would be
3559 * somewhat less than half-way, as it's faster to just count bytes
3560 * than to also copy, and we don't have the overhead of allocating
3561 * a new string, changing the scalar to use it, and freeing the
3562 * existing one. But if the memory copy is fast, the break-even
3563 * point is somewhere after half way. The counting loop could be
3564 * sped up by vectorization, etc, to move the break-even point
3565 * further towards the beginning.
3566 * 2) if the string doesn't have enough space to handle the converted
3567 * value. A new string will have to be allocated, and one might
3568 * as well, given that, start from the beginning doing the first
3569 * method. We've spent extra time parsing the string and in
3570 * exchange all we've gotten is that we know precisely how big to
3571 * make the new one. Perl is more optimized for time than space,
3572 * so this case is a loser.
3573 * So what I've decided to do is not use the 2nd method unless it is
3574 * guaranteed that a new string won't have to be allocated, assuming
3575 * the worst case. I also decided not to put any more conditions on it
3576 * than this, for now. It seems likely that, since the worst case is
3577 * twice as big as the unknown portion of the string (plus 1), we won't
3578 * be guaranteed enough space, causing us to go to the first method,
3579 * unless the string is short, or the first variant character is near
3580 * the end of it. In either of these cases, it seems best to use the
3581 * 2nd method. The only circumstance I can think of where this would
3582 * be really slower is if the string had once had much more data in it
3583 * than it does now, but there is still a substantial amount in it */
3584
3585 {
3586 STRLEN invariant_head = t - s;
3587