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Move regex global variables to interpreter level
[perl5.git] / sv.c
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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 *
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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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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.
17c7a51d 134
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135An SV (or AV, HV, etc.) is allocated in two parts: the head (struct
136sv, av, hv...) contains type and reference count information, and for
137many types, a pointer to the body (struct xrv, xpv, xpviv...), which
138contains fields specific to each type. Some types store all they need
139in the head, so don't have a body.
140
486ec47a 141In all but the most memory-paranoid configurations (ex: PURIFY), heads
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142and bodies are allocated out of arenas, which by default are
143approximately 4K chunks of memory parcelled up into N heads or bodies.
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144Sv-bodies are allocated by their sv-type, guaranteeing size
145consistency needed to allocate safely from arrays.
146
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147For SV-heads, the first slot in each arena is reserved, and holds a
148link to the next arena, some flags, and a note of the number of slots.
149Snaked through each arena chain is a linked list of free items; when
150this becomes empty, an extra arena is allocated and divided up into N
151items which are threaded into the free list.
152
153SV-bodies are similar, but they use arena-sets by default, which
154separate the link and info from the arena itself, and reclaim the 1st
155slot in the arena. SV-bodies are further described later.
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156
157The following global variables are associated with arenas:
158
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159 PL_sv_arenaroot pointer to list of SV arenas
160 PL_sv_root pointer to list of free SV structures
645c22ef 161
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162 PL_body_arenas head of linked-list of body arenas
163 PL_body_roots[] array of pointers to list of free bodies of svtype
164 arrays are indexed by the svtype needed
93e68bfb 165
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166A few special SV heads are not allocated from an arena, but are
167instead directly created in the interpreter structure, eg PL_sv_undef.
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168The size of arenas can be changed from the default by setting
169PERL_ARENA_SIZE appropriately at compile time.
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170
171The SV arena serves the secondary purpose of allowing still-live SVs
172to be located and destroyed during final cleanup.
173
174At the lowest level, the macros new_SV() and del_SV() grab and free
175an SV head. (If debugging with -DD, del_SV() calls the function S_del_sv()
176to return the SV to the free list with error checking.) new_SV() calls
177more_sv() / sv_add_arena() to add an extra arena if the free list is empty.
178SVs in the free list have their SvTYPE field set to all ones.
179
ff276b08 180At the time of very final cleanup, sv_free_arenas() is called from
645c22ef 181perl_destruct() to physically free all the arenas allocated since the
6a93a7e5 182start of the interpreter.
645c22ef 183
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184The function visit() scans the SV arenas list, and calls a specified
185function for each SV it finds which is still live - ie which has an SvTYPE
186other than all 1's, and a non-zero SvREFCNT. visit() is used by the
187following functions (specified as [function that calls visit()] / [function
188called by visit() for each SV]):
189
190 sv_report_used() / do_report_used()
f2524eef 191 dump all remaining SVs (debugging aid)
645c22ef 192
e4487e9b 193 sv_clean_objs() / do_clean_objs(),do_clean_named_objs(),
e76981f9 194 do_clean_named_io_objs(),do_curse()
645c22ef 195 Attempt to free all objects pointed to by RVs,
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196 try to do the same for all objects indir-
197 ectly referenced by typeglobs too, and
198 then do a final sweep, cursing any
199 objects that remain. Called once from
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200 perl_destruct(), prior to calling sv_clean_all()
201 below.
202
203 sv_clean_all() / do_clean_all()
204 SvREFCNT_dec(sv) each remaining SV, possibly
205 triggering an sv_free(). It also sets the
206 SVf_BREAK flag on the SV to indicate that the
207 refcnt has been artificially lowered, and thus
208 stopping sv_free() from giving spurious warnings
209 about SVs which unexpectedly have a refcnt
210 of zero. called repeatedly from perl_destruct()
211 until there are no SVs left.
212
93e68bfb 213=head2 Arena allocator API Summary
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214
215Private API to rest of sv.c
216
217 new_SV(), del_SV(),
218
df0f0429 219 new_XPVNV(), del_XPVGV(),
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220 etc
221
222Public API:
223
8cf8f3d1 224 sv_report_used(), sv_clean_objs(), sv_clean_all(), sv_free_arenas()
645c22ef 225
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226=cut
227
3e8320cc 228 * ========================================================================= */
645c22ef 229
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230/*
231 * "A time to plant, and a time to uproot what was planted..."
232 */
233
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234#ifdef PERL_MEM_LOG
235# define MEM_LOG_NEW_SV(sv, file, line, func) \
236 Perl_mem_log_new_sv(sv, file, line, func)
237# define MEM_LOG_DEL_SV(sv, file, line, func) \
238 Perl_mem_log_del_sv(sv, file, line, func)
239#else
240# define MEM_LOG_NEW_SV(sv, file, line, func) NOOP
241# define MEM_LOG_DEL_SV(sv, file, line, func) NOOP
242#endif
243
fd0854ff 244#ifdef DEBUG_LEAKING_SCALARS
484e6108
FC
245# define FREE_SV_DEBUG_FILE(sv) STMT_START { \
246 if ((sv)->sv_debug_file) PerlMemShared_free((sv)->sv_debug_file); \
247 } STMT_END
d7a2c63c 248# define DEBUG_SV_SERIAL(sv) \
147e3846 249 DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf ": (%05ld) del_SV\n", \
d7a2c63c 250 PTR2UV(sv), (long)(sv)->sv_debug_serial))
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251#else
252# define FREE_SV_DEBUG_FILE(sv)
d7a2c63c 253# define DEBUG_SV_SERIAL(sv) NOOP
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254#endif
255
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NC
256#ifdef PERL_POISON
257# define SvARENA_CHAIN(sv) ((sv)->sv_u.svu_rv)
daba3364 258# define SvARENA_CHAIN_SET(sv,val) (sv)->sv_u.svu_rv = MUTABLE_SV((val))
48614a46
NC
259/* Whilst I'd love to do this, it seems that things like to check on
260 unreferenced scalars
ce5dbf61 261# define POISON_SV_HEAD(sv) PoisonNew(sv, 1, struct STRUCT_SV)
48614a46 262*/
ce5dbf61 263# define POISON_SV_HEAD(sv) PoisonNew(&SvANY(sv), 1, void *), \
7e337ee0 264 PoisonNew(&SvREFCNT(sv), 1, U32)
48614a46
NC
265#else
266# define SvARENA_CHAIN(sv) SvANY(sv)
3eef1deb 267# define SvARENA_CHAIN_SET(sv,val) SvANY(sv) = (void *)(val)
ce5dbf61 268# define POISON_SV_HEAD(sv)
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NC
269#endif
270
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DM
271/* Mark an SV head as unused, and add to free list.
272 *
273 * If SVf_BREAK is set, skip adding it to the free list, as this SV had
274 * its refcount artificially decremented during global destruction, so
275 * there may be dangling pointers to it. The last thing we want in that
276 * case is for it to be reused. */
277
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278#define plant_SV(p) \
279 STMT_START { \
990198f0 280 const U32 old_flags = SvFLAGS(p); \
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281 MEM_LOG_DEL_SV(p, __FILE__, __LINE__, FUNCTION__); \
282 DEBUG_SV_SERIAL(p); \
fd0854ff 283 FREE_SV_DEBUG_FILE(p); \
ce5dbf61 284 POISON_SV_HEAD(p); \
053fc874 285 SvFLAGS(p) = SVTYPEMASK; \
990198f0 286 if (!(old_flags & SVf_BREAK)) { \
3eef1deb 287 SvARENA_CHAIN_SET(p, PL_sv_root); \
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288 PL_sv_root = (p); \
289 } \
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290 --PL_sv_count; \
291 } STMT_END
a0d0e21e 292
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293#define uproot_SV(p) \
294 STMT_START { \
295 (p) = PL_sv_root; \
daba3364 296 PL_sv_root = MUTABLE_SV(SvARENA_CHAIN(p)); \
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297 ++PL_sv_count; \
298 } STMT_END
299
645c22ef 300
cac9b346
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301/* make some more SVs by adding another arena */
302
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NC
303STATIC SV*
304S_more_sv(pTHX)
305{
306 SV* sv;
9a87bd09
NC
307 char *chunk; /* must use New here to match call to */
308 Newx(chunk,PERL_ARENA_SIZE,char); /* Safefree() in sv_free_arenas() */
309 sv_add_arena(chunk, PERL_ARENA_SIZE, 0);
cac9b346
NC
310 uproot_SV(sv);
311 return sv;
312}
313
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314/* new_SV(): return a new, empty SV head */
315
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316#ifdef DEBUG_LEAKING_SCALARS
317/* provide a real function for a debugger to play with */
318STATIC SV*
d7a2c63c 319S_new_SV(pTHX_ const char *file, int line, const char *func)
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320{
321 SV* sv;
322
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DM
323 if (PL_sv_root)
324 uproot_SV(sv);
325 else
cac9b346 326 sv = S_more_sv(aTHX);
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327 SvANY(sv) = 0;
328 SvREFCNT(sv) = 1;
329 SvFLAGS(sv) = 0;
fd0854ff 330 sv->sv_debug_optype = PL_op ? PL_op->op_type : 0;
e385c3bf
DM
331 sv->sv_debug_line = (U16) (PL_parser && PL_parser->copline != NOLINE
332 ? PL_parser->copline
333 : PL_curcop
f24aceb1
DM
334 ? CopLINE(PL_curcop)
335 : 0
e385c3bf 336 );
fd0854ff 337 sv->sv_debug_inpad = 0;
cd676548 338 sv->sv_debug_parent = NULL;
484e6108 339 sv->sv_debug_file = PL_curcop ? savesharedpv(CopFILE(PL_curcop)): NULL;
d7a2c63c
MHM
340
341 sv->sv_debug_serial = PL_sv_serial++;
342
343 MEM_LOG_NEW_SV(sv, file, line, func);
147e3846 344 DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%" UVxf ": (%05ld) new_SV (from %s:%d [%s])\n",
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MHM
345 PTR2UV(sv), (long)sv->sv_debug_serial, file, line, func));
346
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347 return sv;
348}
d7a2c63c 349# define new_SV(p) (p)=S_new_SV(aTHX_ __FILE__, __LINE__, FUNCTION__)
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350
351#else
352# define new_SV(p) \
053fc874 353 STMT_START { \
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354 if (PL_sv_root) \
355 uproot_SV(p); \
356 else \
cac9b346 357 (p) = S_more_sv(aTHX); \
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358 SvANY(p) = 0; \
359 SvREFCNT(p) = 1; \
360 SvFLAGS(p) = 0; \
d7a2c63c 361 MEM_LOG_NEW_SV(p, __FILE__, __LINE__, FUNCTION__); \
053fc874 362 } STMT_END
eba0f806 363#endif
463ee0b2 364
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365
366/* del_SV(): return an empty SV head to the free list */
367
a0d0e21e 368#ifdef DEBUGGING
4561caa4 369
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370#define del_SV(p) \
371 STMT_START { \
aea4f609 372 if (DEBUG_D_TEST) \
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373 del_sv(p); \
374 else \
375 plant_SV(p); \
053fc874 376 } STMT_END
a0d0e21e 377
76e3520e 378STATIC void
cea2e8a9 379S_del_sv(pTHX_ SV *p)
463ee0b2 380{
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NC
381 PERL_ARGS_ASSERT_DEL_SV;
382
aea4f609 383 if (DEBUG_D_TEST) {
4633a7c4 384 SV* sva;
a3b680e6 385 bool ok = 0;
daba3364 386 for (sva = PL_sv_arenaroot; sva; sva = MUTABLE_SV(SvANY(sva))) {
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AL
387 const SV * const sv = sva + 1;
388 const SV * const svend = &sva[SvREFCNT(sva)];
c0ff570e 389 if (p >= sv && p < svend) {
a0d0e21e 390 ok = 1;
c0ff570e
NC
391 break;
392 }
a0d0e21e
LW
393 }
394 if (!ok) {
9b387841 395 Perl_ck_warner_d(aTHX_ packWARN(WARN_INTERNAL),
147e3846 396 "Attempt to free non-arena SV: 0x%" UVxf
9b387841 397 pTHX__FORMAT, PTR2UV(p) pTHX__VALUE);
a0d0e21e
LW
398 return;
399 }
400 }
4561caa4 401 plant_SV(p);
463ee0b2 402}
a0d0e21e 403
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404#else /* ! DEBUGGING */
405
406#define del_SV(p) plant_SV(p)
407
408#endif /* DEBUGGING */
463ee0b2 409
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410
411/*
ccfc67b7
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412=head1 SV Manipulation Functions
413
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414=for apidoc sv_add_arena
415
416Given a chunk of memory, link it to the head of the list of arenas,
417and split it into a list of free SVs.
418
419=cut
420*/
421
d2bd4e7f
NC
422static void
423S_sv_add_arena(pTHX_ char *const ptr, const U32 size, const U32 flags)
463ee0b2 424{
daba3364 425 SV *const sva = MUTABLE_SV(ptr);
eb578fdb
KW
426 SV* sv;
427 SV* svend;
4633a7c4 428
7918f24d
NC
429 PERL_ARGS_ASSERT_SV_ADD_ARENA;
430
4633a7c4 431 /* The first SV in an arena isn't an SV. */
3280af22 432 SvANY(sva) = (void *) PL_sv_arenaroot; /* ptr to next arena */
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LW
433 SvREFCNT(sva) = size / sizeof(SV); /* number of SV slots */
434 SvFLAGS(sva) = flags; /* FAKE if not to be freed */
435
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436 PL_sv_arenaroot = sva;
437 PL_sv_root = sva + 1;
4633a7c4
LW
438
439 svend = &sva[SvREFCNT(sva) - 1];
440 sv = sva + 1;
463ee0b2 441 while (sv < svend) {
3eef1deb 442 SvARENA_CHAIN_SET(sv, (sv + 1));
03e36789 443#ifdef DEBUGGING
978b032e 444 SvREFCNT(sv) = 0;
03e36789 445#endif
4b69cbe3 446 /* Must always set typemask because it's always checked in on cleanup
03e36789 447 when the arenas are walked looking for objects. */
8990e307 448 SvFLAGS(sv) = SVTYPEMASK;
463ee0b2
LW
449 sv++;
450 }
3eef1deb 451 SvARENA_CHAIN_SET(sv, 0);
03e36789
NC
452#ifdef DEBUGGING
453 SvREFCNT(sv) = 0;
454#endif
4633a7c4
LW
455 SvFLAGS(sv) = SVTYPEMASK;
456}
457
055972dc
DM
458/* visit(): call the named function for each non-free SV in the arenas
459 * whose flags field matches the flags/mask args. */
645c22ef 460
5226ed68 461STATIC I32
de37a194 462S_visit(pTHX_ SVFUNC_t f, const U32 flags, const U32 mask)
8990e307 463{
4633a7c4 464 SV* sva;
5226ed68 465 I32 visited = 0;
8990e307 466
7918f24d
NC
467 PERL_ARGS_ASSERT_VISIT;
468
daba3364 469 for (sva = PL_sv_arenaroot; sva; sva = MUTABLE_SV(SvANY(sva))) {
eb578fdb
KW
470 const SV * const svend = &sva[SvREFCNT(sva)];
471 SV* sv;
4561caa4 472 for (sv = sva + 1; sv < svend; ++sv) {
e4787c0c 473 if (SvTYPE(sv) != (svtype)SVTYPEMASK
055972dc
DM
474 && (sv->sv_flags & mask) == flags
475 && SvREFCNT(sv))
476 {
942481a7 477 (*f)(aTHX_ sv);
5226ed68
JH
478 ++visited;
479 }
8990e307
LW
480 }
481 }
5226ed68 482 return visited;
8990e307
LW
483}
484
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JH
485#ifdef DEBUGGING
486
645c22ef
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487/* called by sv_report_used() for each live SV */
488
489static void
5fa45a31 490do_report_used(pTHX_ SV *const sv)
645c22ef 491{
e4787c0c 492 if (SvTYPE(sv) != (svtype)SVTYPEMASK) {
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DM
493 PerlIO_printf(Perl_debug_log, "****\n");
494 sv_dump(sv);
495 }
496}
758a08c3 497#endif
645c22ef
DM
498
499/*
500=for apidoc sv_report_used
501
fde67290 502Dump the contents of all SVs not yet freed (debugging aid).
645c22ef
DM
503
504=cut
505*/
506
8990e307 507void
864dbfa3 508Perl_sv_report_used(pTHX)
4561caa4 509{
ff270d3a 510#ifdef DEBUGGING
055972dc 511 visit(do_report_used, 0, 0);
96a5add6
AL
512#else
513 PERL_UNUSED_CONTEXT;
ff270d3a 514#endif
4561caa4
CS
515}
516
645c22ef
DM
517/* called by sv_clean_objs() for each live SV */
518
519static void
de37a194 520do_clean_objs(pTHX_ SV *const ref)
645c22ef 521{
ea724faa
NC
522 assert (SvROK(ref));
523 {
823a54a3
AL
524 SV * const target = SvRV(ref);
525 if (SvOBJECT(target)) {
526 DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning object ref:\n "), sv_dump(ref)));
527 if (SvWEAKREF(ref)) {
528 sv_del_backref(target, ref);
529 SvWEAKREF_off(ref);
530 SvRV_set(ref, NULL);
531 } else {
532 SvROK_off(ref);
533 SvRV_set(ref, NULL);
fc2b2dca 534 SvREFCNT_dec_NN(target);
823a54a3 535 }
645c22ef
DM
536 }
537 }
645c22ef
DM
538}
539
645c22ef 540
e4487e9b
DM
541/* clear any slots in a GV which hold objects - except IO;
542 * called by sv_clean_objs() for each live GV */
543
645c22ef 544static void
f30de749 545do_clean_named_objs(pTHX_ SV *const sv)
645c22ef 546{
57ef47cc 547 SV *obj;
ea724faa 548 assert(SvTYPE(sv) == SVt_PVGV);
d011219a 549 assert(isGV_with_GP(sv));
57ef47cc
DM
550 if (!GvGP(sv))
551 return;
552
553 /* freeing GP entries may indirectly free the current GV;
554 * hold onto it while we mess with the GP slots */
555 SvREFCNT_inc(sv);
556
557 if ( ((obj = GvSV(sv) )) && SvOBJECT(obj)) {
558 DEBUG_D((PerlIO_printf(Perl_debug_log,
559 "Cleaning named glob SV object:\n "), sv_dump(obj)));
560 GvSV(sv) = NULL;
fc2b2dca 561 SvREFCNT_dec_NN(obj);
57ef47cc
DM
562 }
563 if ( ((obj = MUTABLE_SV(GvAV(sv)) )) && SvOBJECT(obj)) {
564 DEBUG_D((PerlIO_printf(Perl_debug_log,
565 "Cleaning named glob AV object:\n "), sv_dump(obj)));
566 GvAV(sv) = NULL;
fc2b2dca 567 SvREFCNT_dec_NN(obj);
57ef47cc
DM
568 }
569 if ( ((obj = MUTABLE_SV(GvHV(sv)) )) && SvOBJECT(obj)) {
570 DEBUG_D((PerlIO_printf(Perl_debug_log,
571 "Cleaning named glob HV object:\n "), sv_dump(obj)));
572 GvHV(sv) = NULL;
fc2b2dca 573 SvREFCNT_dec_NN(obj);
57ef47cc
DM
574 }
575 if ( ((obj = MUTABLE_SV(GvCV(sv)) )) && SvOBJECT(obj)) {
576 DEBUG_D((PerlIO_printf(Perl_debug_log,
577 "Cleaning named glob CV object:\n "), sv_dump(obj)));
c43ae56f 578 GvCV_set(sv, NULL);
fc2b2dca 579 SvREFCNT_dec_NN(obj);
57ef47cc 580 }
fc2b2dca 581 SvREFCNT_dec_NN(sv); /* undo the inc above */
e4487e9b
DM
582}
583
68b590d9 584/* clear any IO slots in a GV which hold objects (except stderr, defout);
e4487e9b
DM
585 * called by sv_clean_objs() for each live GV */
586
587static void
588do_clean_named_io_objs(pTHX_ SV *const sv)
589{
e4487e9b
DM
590 SV *obj;
591 assert(SvTYPE(sv) == SVt_PVGV);
592 assert(isGV_with_GP(sv));
68b590d9 593 if (!GvGP(sv) || sv == (SV*)PL_stderrgv || sv == (SV*)PL_defoutgv)
e4487e9b
DM
594 return;
595
596 SvREFCNT_inc(sv);
57ef47cc
DM
597 if ( ((obj = MUTABLE_SV(GvIO(sv)) )) && SvOBJECT(obj)) {
598 DEBUG_D((PerlIO_printf(Perl_debug_log,
599 "Cleaning named glob IO object:\n "), sv_dump(obj)));
600 GvIOp(sv) = NULL;
fc2b2dca 601 SvREFCNT_dec_NN(obj);
645c22ef 602 }
fc2b2dca 603 SvREFCNT_dec_NN(sv); /* undo the inc above */
645c22ef 604}
645c22ef 605
4155e4fe
FC
606/* Void wrapper to pass to visit() */
607static void
608do_curse(pTHX_ SV * const sv) {
c2910e6c
FC
609 if ((PL_stderrgv && GvGP(PL_stderrgv) && (SV*)GvIO(PL_stderrgv) == sv)
610 || (PL_defoutgv && GvGP(PL_defoutgv) && (SV*)GvIO(PL_defoutgv) == sv))
4155e4fe
FC
611 return;
612 (void)curse(sv, 0);
613}
614
645c22ef
DM
615/*
616=for apidoc sv_clean_objs
617
fde67290 618Attempt to destroy all objects not yet freed.
645c22ef
DM
619
620=cut
621*/
622
4561caa4 623void
864dbfa3 624Perl_sv_clean_objs(pTHX)
4561caa4 625{
68b590d9 626 GV *olddef, *olderr;
3280af22 627 PL_in_clean_objs = TRUE;
055972dc 628 visit(do_clean_objs, SVf_ROK, SVf_ROK);
e4487e9b
DM
629 /* Some barnacles may yet remain, clinging to typeglobs.
630 * Run the non-IO destructors first: they may want to output
631 * error messages, close files etc */
d011219a 632 visit(do_clean_named_objs, SVt_PVGV|SVpgv_GP, SVTYPEMASK|SVp_POK|SVpgv_GP);
e4487e9b 633 visit(do_clean_named_io_objs, SVt_PVGV|SVpgv_GP, SVTYPEMASK|SVp_POK|SVpgv_GP);
4155e4fe
FC
634 /* And if there are some very tenacious barnacles clinging to arrays,
635 closures, or what have you.... */
636 visit(do_curse, SVs_OBJECT, SVs_OBJECT);
68b590d9
DM
637 olddef = PL_defoutgv;
638 PL_defoutgv = NULL; /* disable skip of PL_defoutgv */
639 if (olddef && isGV_with_GP(olddef))
640 do_clean_named_io_objs(aTHX_ MUTABLE_SV(olddef));
641 olderr = PL_stderrgv;
642 PL_stderrgv = NULL; /* disable skip of PL_stderrgv */
643 if (olderr && isGV_with_GP(olderr))
644 do_clean_named_io_objs(aTHX_ MUTABLE_SV(olderr));
645 SvREFCNT_dec(olddef);
3280af22 646 PL_in_clean_objs = FALSE;
4561caa4
CS
647}
648
645c22ef
DM
649/* called by sv_clean_all() for each live SV */
650
651static void
de37a194 652do_clean_all(pTHX_ SV *const sv)
645c22ef 653{
daba3364 654 if (sv == (const SV *) PL_fdpid || sv == (const SV *)PL_strtab) {
cddfcddc 655 /* don't clean pid table and strtab */
d17ea597 656 return;
cddfcddc 657 }
147e3846 658 DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning loops: SV at 0x%" UVxf "\n", PTR2UV(sv)) ));
645c22ef 659 SvFLAGS(sv) |= SVf_BREAK;
fc2b2dca 660 SvREFCNT_dec_NN(sv);
645c22ef
DM
661}
662
663/*
664=for apidoc sv_clean_all
665
666Decrement the refcnt of each remaining SV, possibly triggering a
fde67290 667cleanup. This function may have to be called multiple times to free
ff276b08 668SVs which are in complex self-referential hierarchies.
645c22ef
DM
669
670=cut
671*/
672
5226ed68 673I32
864dbfa3 674Perl_sv_clean_all(pTHX)
8990e307 675{
5226ed68 676 I32 cleaned;
3280af22 677 PL_in_clean_all = TRUE;
055972dc 678 cleaned = visit(do_clean_all, 0,0);
5226ed68 679 return cleaned;
8990e307 680}
463ee0b2 681
5e258f8c
JC
682/*
683 ARENASETS: a meta-arena implementation which separates arena-info
684 into struct arena_set, which contains an array of struct
685 arena_descs, each holding info for a single arena. By separating
686 the meta-info from the arena, we recover the 1st slot, formerly
687 borrowed for list management. The arena_set is about the size of an
39244528 688 arena, avoiding the needless malloc overhead of a naive linked-list.
5e258f8c
JC
689
690 The cost is 1 arena-set malloc per ~320 arena-mallocs, + the unused
691 memory in the last arena-set (1/2 on average). In trade, we get
692 back the 1st slot in each arena (ie 1.7% of a CV-arena, less for
d2a0f284 693 smaller types). The recovery of the wasted space allows use of
e15dad31
JC
694 small arenas for large, rare body types, by changing array* fields
695 in body_details_by_type[] below.
5e258f8c 696*/
5e258f8c 697struct arena_desc {
398c677b
NC
698 char *arena; /* the raw storage, allocated aligned */
699 size_t size; /* its size ~4k typ */
e5973ed5 700 svtype utype; /* bodytype stored in arena */
5e258f8c
JC
701};
702
e6148039
NC
703struct arena_set;
704
705/* Get the maximum number of elements in set[] such that struct arena_set
e15dad31 706 will fit within PERL_ARENA_SIZE, which is probably just under 4K, and
e6148039
NC
707 therefore likely to be 1 aligned memory page. */
708
709#define ARENAS_PER_SET ((PERL_ARENA_SIZE - sizeof(struct arena_set*) \
710 - 2 * sizeof(int)) / sizeof (struct arena_desc))
5e258f8c
JC
711
712struct arena_set {
713 struct arena_set* next;
0a848332
NC
714 unsigned int set_size; /* ie ARENAS_PER_SET */
715 unsigned int curr; /* index of next available arena-desc */
5e258f8c
JC
716 struct arena_desc set[ARENAS_PER_SET];
717};
718
645c22ef
DM
719/*
720=for apidoc sv_free_arenas
721
fde67290 722Deallocate the memory used by all arenas. Note that all the individual SV
645c22ef
DM
723heads and bodies within the arenas must already have been freed.
724
725=cut
7fefc6c1 726
645c22ef 727*/
4633a7c4 728void
864dbfa3 729Perl_sv_free_arenas(pTHX)
4633a7c4
LW
730{
731 SV* sva;
732 SV* svanext;
0a848332 733 unsigned int i;
4633a7c4
LW
734
735 /* Free arenas here, but be careful about fake ones. (We assume
736 contiguity of the fake ones with the corresponding real ones.) */
737
3280af22 738 for (sva = PL_sv_arenaroot; sva; sva = svanext) {
daba3364 739 svanext = MUTABLE_SV(SvANY(sva));
4633a7c4 740 while (svanext && SvFAKE(svanext))
daba3364 741 svanext = MUTABLE_SV(SvANY(svanext));
4633a7c4
LW
742
743 if (!SvFAKE(sva))
1df70142 744 Safefree(sva);
4633a7c4 745 }
93e68bfb 746
5e258f8c 747 {
0a848332
NC
748 struct arena_set *aroot = (struct arena_set*) PL_body_arenas;
749
750 while (aroot) {
751 struct arena_set *current = aroot;
752 i = aroot->curr;
753 while (i--) {
5e258f8c
JC
754 assert(aroot->set[i].arena);
755 Safefree(aroot->set[i].arena);
756 }
0a848332
NC
757 aroot = aroot->next;
758 Safefree(current);
5e258f8c
JC
759 }
760 }
dc8220bf 761 PL_body_arenas = 0;
fdda85ca 762
0a848332
NC
763 i = PERL_ARENA_ROOTS_SIZE;
764 while (i--)
93e68bfb 765 PL_body_roots[i] = 0;
93e68bfb 766
3280af22
NIS
767 PL_sv_arenaroot = 0;
768 PL_sv_root = 0;
4633a7c4
LW
769}
770
bd81e77b
NC
771/*
772 Here are mid-level routines that manage the allocation of bodies out
cc463ce5 773 of the various arenas. There are 4 kinds of arenas:
29489e7c 774
bd81e77b
NC
775 1. SV-head arenas, which are discussed and handled above
776 2. regular body arenas
777 3. arenas for reduced-size bodies
778 4. Hash-Entry arenas
29489e7c 779
bd81e77b
NC
780 Arena types 2 & 3 are chained by body-type off an array of
781 arena-root pointers, which is indexed by svtype. Some of the
782 larger/less used body types are malloced singly, since a large
783 unused block of them is wasteful. Also, several svtypes dont have
784 bodies; the data fits into the sv-head itself. The arena-root
785 pointer thus has a few unused root-pointers (which may be hijacked
cc463ce5 786 later for arena type 4)
29489e7c 787
bd81e77b
NC
788 3 differs from 2 as an optimization; some body types have several
789 unused fields in the front of the structure (which are kept in-place
790 for consistency). These bodies can be allocated in smaller chunks,
791 because the leading fields arent accessed. Pointers to such bodies
792 are decremented to point at the unused 'ghost' memory, knowing that
793 the pointers are used with offsets to the real memory.
29489e7c 794
d2a0f284
JC
795Allocation of SV-bodies is similar to SV-heads, differing as follows;
796the allocation mechanism is used for many body types, so is somewhat
797more complicated, it uses arena-sets, and has no need for still-live
798SV detection.
799
800At the outermost level, (new|del)_X*V macros return bodies of the
801appropriate type. These macros call either (new|del)_body_type or
802(new|del)_body_allocated macro pairs, depending on specifics of the
803type. Most body types use the former pair, the latter pair is used to
804allocate body types with "ghost fields".
805
806"ghost fields" are fields that are unused in certain types, and
69ba284b 807consequently don't need to actually exist. They are declared because
d2a0f284
JC
808they're part of a "base type", which allows use of functions as
809methods. The simplest examples are AVs and HVs, 2 aggregate types
810which don't use the fields which support SCALAR semantics.
811
69ba284b 812For these types, the arenas are carved up into appropriately sized
d2a0f284
JC
813chunks, we thus avoid wasted memory for those unaccessed members.
814When bodies are allocated, we adjust the pointer back in memory by the
69ba284b 815size of the part not allocated, so it's as if we allocated the full
d2a0f284
JC
816structure. (But things will all go boom if you write to the part that
817is "not there", because you'll be overwriting the last members of the
818preceding structure in memory.)
819
69ba284b 820We calculate the correction using the STRUCT_OFFSET macro on the first
a05ea1cf 821member present. If the allocated structure is smaller (no initial NV
69ba284b
NC
822actually allocated) then the net effect is to subtract the size of the NV
823from the pointer, to return a new pointer as if an initial NV were actually
a05ea1cf 824allocated. (We were using structures named *_allocated for this, but
69ba284b
NC
825this turned out to be a subtle bug, because a structure without an NV
826could have a lower alignment constraint, but the compiler is allowed to
827optimised accesses based on the alignment constraint of the actual pointer
828to the full structure, for example, using a single 64 bit load instruction
829because it "knows" that two adjacent 32 bit members will be 8-byte aligned.)
d2a0f284 830
a05ea1cf 831This is the same trick as was used for NV and IV bodies. Ironically it
d2a0f284 832doesn't need to be used for NV bodies any more, because NV is now at
5b306eef
DD
833the start of the structure. IV bodies, and also in some builds NV bodies,
834don't need it either, because they are no longer allocated.
d2a0f284
JC
835
836In turn, the new_body_* allocators call S_new_body(), which invokes
837new_body_inline macro, which takes a lock, and takes a body off the
1e30fcd5 838linked list at PL_body_roots[sv_type], calling Perl_more_bodies() if
d2a0f284
JC
839necessary to refresh an empty list. Then the lock is released, and
840the body is returned.
841
99816f8d 842Perl_more_bodies allocates a new arena, and carves it up into an array of N
d2a0f284
JC
843bodies, which it strings into a linked list. It looks up arena-size
844and body-size from the body_details table described below, thus
845supporting the multiple body-types.
846
847If PURIFY is defined, or PERL_ARENA_SIZE=0, arenas are not used, and
848the (new|del)_X*V macros are mapped directly to malloc/free.
849
d2a0f284
JC
850For each sv-type, struct body_details bodies_by_type[] carries
851parameters which control these aspects of SV handling:
852
853Arena_size determines whether arenas are used for this body type, and if
854so, how big they are. PURIFY or PERL_ARENA_SIZE=0 set this field to
855zero, forcing individual mallocs and frees.
856
857Body_size determines how big a body is, and therefore how many fit into
858each arena. Offset carries the body-pointer adjustment needed for
69ba284b 859"ghost fields", and is used in *_allocated macros.
d2a0f284
JC
860
861But its main purpose is to parameterize info needed in
862Perl_sv_upgrade(). The info here dramatically simplifies the function
69ba284b 863vs the implementation in 5.8.8, making it table-driven. All fields
d2a0f284
JC
864are used for this, except for arena_size.
865
866For the sv-types that have no bodies, arenas are not used, so those
867PL_body_roots[sv_type] are unused, and can be overloaded. In
868something of a special case, SVt_NULL is borrowed for HE arenas;
c6f8b1d0 869PL_body_roots[HE_SVSLOT=SVt_NULL] is filled by S_more_he, but the
d2a0f284 870bodies_by_type[SVt_NULL] slot is not used, as the table is not
c6f8b1d0 871available in hv.c.
d2a0f284 872
29489e7c
DM
873*/
874
bd81e77b 875struct body_details {
0fb58b32 876 U8 body_size; /* Size to allocate */
10666ae3 877 U8 copy; /* Size of structure to copy (may be shorter) */
5b306eef
DD
878 U8 offset; /* Size of unalloced ghost fields to first alloced field*/
879 PERL_BITFIELD8 type : 4; /* We have space for a sanity check. */
880 PERL_BITFIELD8 cant_upgrade : 1;/* Cannot upgrade this type */
881 PERL_BITFIELD8 zero_nv : 1; /* zero the NV when upgrading from this */
882 PERL_BITFIELD8 arena : 1; /* Allocated from an arena */
883 U32 arena_size; /* Size of arena to allocate */
bd81e77b 884};
29489e7c 885
bd81e77b
NC
886#define HADNV FALSE
887#define NONV TRUE
29489e7c 888
d2a0f284 889
bd81e77b
NC
890#ifdef PURIFY
891/* With -DPURFIY we allocate everything directly, and don't use arenas.
892 This seems a rather elegant way to simplify some of the code below. */
893#define HASARENA FALSE
894#else
895#define HASARENA TRUE
896#endif
897#define NOARENA FALSE
29489e7c 898
d2a0f284
JC
899/* Size the arenas to exactly fit a given number of bodies. A count
900 of 0 fits the max number bodies into a PERL_ARENA_SIZE.block,
901 simplifying the default. If count > 0, the arena is sized to fit
902 only that many bodies, allowing arenas to be used for large, rare
903 bodies (XPVFM, XPVIO) without undue waste. The arena size is
904 limited by PERL_ARENA_SIZE, so we can safely oversize the
905 declarations.
906 */
95db5f15
MB
907#define FIT_ARENA0(body_size) \
908 ((size_t)(PERL_ARENA_SIZE / body_size) * body_size)
909#define FIT_ARENAn(count,body_size) \
910 ( count * body_size <= PERL_ARENA_SIZE) \
911 ? count * body_size \
912 : FIT_ARENA0 (body_size)
913#define FIT_ARENA(count,body_size) \
cd1dc8e2 914 (U32)(count \
95db5f15 915 ? FIT_ARENAn (count, body_size) \
cd1dc8e2 916 : FIT_ARENA0 (body_size))
d2a0f284 917
bd81e77b
NC
918/* Calculate the length to copy. Specifically work out the length less any
919 final padding the compiler needed to add. See the comment in sv_upgrade
920 for why copying the padding proved to be a bug. */
29489e7c 921
bd81e77b
NC
922#define copy_length(type, last_member) \
923 STRUCT_OFFSET(type, last_member) \
daba3364 924 + sizeof (((type*)SvANY((const SV *)0))->last_member)
29489e7c 925
bd81e77b 926static const struct body_details bodies_by_type[] = {
829cd18a
NC
927 /* HEs use this offset for their arena. */
928 { 0, 0, 0, SVt_NULL, FALSE, NONV, NOARENA, 0 },
d2a0f284 929
db93c0c4
NC
930 /* IVs are in the head, so the allocation size is 0. */
931 { 0,
d2a0f284 932 sizeof(IV), /* This is used to copy out the IV body. */
10666ae3 933 STRUCT_OFFSET(XPVIV, xiv_iv), SVt_IV, FALSE, NONV,
db93c0c4 934 NOARENA /* IVS don't need an arena */, 0
d2a0f284
JC
935 },
936
5b306eef
DD
937#if NVSIZE <= IVSIZE
938 { 0, sizeof(NV),
939 STRUCT_OFFSET(XPVNV, xnv_u),
940 SVt_NV, FALSE, HADNV, NOARENA, 0 },
941#else
6e128786
NC
942 { sizeof(NV), sizeof(NV),
943 STRUCT_OFFSET(XPVNV, xnv_u),
944 SVt_NV, FALSE, HADNV, HASARENA, FIT_ARENA(0, sizeof(NV)) },
5b306eef 945#endif
d2a0f284 946
bc337e5c 947 { sizeof(XPV) - STRUCT_OFFSET(XPV, xpv_cur),
889d28b2
NC
948 copy_length(XPV, xpv_len) - STRUCT_OFFSET(XPV, xpv_cur),
949 + STRUCT_OFFSET(XPV, xpv_cur),
69ba284b 950 SVt_PV, FALSE, NONV, HASARENA,
889d28b2 951 FIT_ARENA(0, sizeof(XPV) - STRUCT_OFFSET(XPV, xpv_cur)) },
d2a0f284 952
d361b004
KW
953 { sizeof(XINVLIST) - STRUCT_OFFSET(XPV, xpv_cur),
954 copy_length(XINVLIST, is_offset) - STRUCT_OFFSET(XPV, xpv_cur),
955 + STRUCT_OFFSET(XPV, xpv_cur),
956 SVt_INVLIST, TRUE, NONV, HASARENA,
957 FIT_ARENA(0, sizeof(XINVLIST) - STRUCT_OFFSET(XPV, xpv_cur)) },
e94d9b54 958
bc337e5c 959 { sizeof(XPVIV) - STRUCT_OFFSET(XPV, xpv_cur),
889d28b2
NC
960 copy_length(XPVIV, xiv_u) - STRUCT_OFFSET(XPV, xpv_cur),
961 + STRUCT_OFFSET(XPV, xpv_cur),
962 SVt_PVIV, FALSE, NONV, HASARENA,
963 FIT_ARENA(0, sizeof(XPVIV) - STRUCT_OFFSET(XPV, xpv_cur)) },
d2a0f284 964
bc337e5c 965 { sizeof(XPVNV) - STRUCT_OFFSET(XPV, xpv_cur),
889d28b2
NC
966 copy_length(XPVNV, xnv_u) - STRUCT_OFFSET(XPV, xpv_cur),
967 + STRUCT_OFFSET(XPV, xpv_cur),
968 SVt_PVNV, FALSE, HADNV, HASARENA,
969 FIT_ARENA(0, sizeof(XPVNV) - STRUCT_OFFSET(XPV, xpv_cur)) },
d2a0f284 970
6e128786 971 { sizeof(XPVMG), copy_length(XPVMG, xnv_u), 0, SVt_PVMG, FALSE, HADNV,
d2a0f284 972 HASARENA, FIT_ARENA(0, sizeof(XPVMG)) },
4df7f6af 973
601dfd0a
NC
974 { sizeof(regexp),
975 sizeof(regexp),
976 0,
ecff11eb 977 SVt_REGEXP, TRUE, NONV, HASARENA,
eaeb1e7f 978 FIT_ARENA(0, sizeof(regexp))
5c35adbb 979 },
4df7f6af 980
10666ae3 981 { sizeof(XPVGV), sizeof(XPVGV), 0, SVt_PVGV, TRUE, HADNV,
d2a0f284
JC
982 HASARENA, FIT_ARENA(0, sizeof(XPVGV)) },
983
10666ae3 984 { sizeof(XPVLV), sizeof(XPVLV), 0, SVt_PVLV, TRUE, HADNV,
d2a0f284
JC
985 HASARENA, FIT_ARENA(0, sizeof(XPVLV)) },
986
601dfd0a 987 { sizeof(XPVAV),
4f7003f5 988 copy_length(XPVAV, xav_alloc),
601dfd0a 989 0,
69ba284b 990 SVt_PVAV, TRUE, NONV, HASARENA,
601dfd0a 991 FIT_ARENA(0, sizeof(XPVAV)) },
d2a0f284 992
601dfd0a 993 { sizeof(XPVHV),
359164a0 994 copy_length(XPVHV, xhv_max),
601dfd0a 995 0,
69ba284b 996 SVt_PVHV, TRUE, NONV, HASARENA,
601dfd0a 997 FIT_ARENA(0, sizeof(XPVHV)) },
d2a0f284 998
601dfd0a
NC
999 { sizeof(XPVCV),
1000 sizeof(XPVCV),
1001 0,
69ba284b 1002 SVt_PVCV, TRUE, NONV, HASARENA,
601dfd0a 1003 FIT_ARENA(0, sizeof(XPVCV)) },
69ba284b 1004
601dfd0a
NC
1005 { sizeof(XPVFM),
1006 sizeof(XPVFM),
1007 0,
69ba284b 1008 SVt_PVFM, TRUE, NONV, NOARENA,
601dfd0a 1009 FIT_ARENA(20, sizeof(XPVFM)) },
d2a0f284 1010
601dfd0a
NC
1011 { sizeof(XPVIO),
1012 sizeof(XPVIO),
1013 0,
b6f60916 1014 SVt_PVIO, TRUE, NONV, HASARENA,
601dfd0a 1015 FIT_ARENA(24, sizeof(XPVIO)) },
bd81e77b 1016};
29489e7c 1017
bd81e77b 1018#define new_body_allocated(sv_type) \
d2a0f284 1019 (void *)((char *)S_new_body(aTHX_ sv_type) \
bd81e77b 1020 - bodies_by_type[sv_type].offset)
29489e7c 1021
26359cfa
NC
1022/* return a thing to the free list */
1023
1024#define del_body(thing, root) \
1025 STMT_START { \
1026 void ** const thing_copy = (void **)thing; \
1027 *thing_copy = *root; \
1028 *root = (void*)thing_copy; \
1029 } STMT_END
29489e7c 1030
bd81e77b 1031#ifdef PURIFY
5b306eef
DD
1032#if !(NVSIZE <= IVSIZE)
1033# define new_XNV() safemalloc(sizeof(XPVNV))
1034#endif
beeec492
NC
1035#define new_XPVNV() safemalloc(sizeof(XPVNV))
1036#define new_XPVMG() safemalloc(sizeof(XPVMG))
29489e7c 1037
beeec492 1038#define del_XPVGV(p) safefree(p)
29489e7c 1039
bd81e77b 1040#else /* !PURIFY */
29489e7c 1041
5b306eef
DD
1042#if !(NVSIZE <= IVSIZE)
1043# define new_XNV() new_body_allocated(SVt_NV)
1044#endif
65ac1738 1045#define new_XPVNV() new_body_allocated(SVt_PVNV)
65ac1738 1046#define new_XPVMG() new_body_allocated(SVt_PVMG)
645c22ef 1047
26359cfa
NC
1048#define del_XPVGV(p) del_body(p + bodies_by_type[SVt_PVGV].offset, \
1049 &PL_body_roots[SVt_PVGV])
1d7c1841 1050
bd81e77b 1051#endif /* PURIFY */
93e68bfb 1052
bd81e77b 1053/* no arena for you! */
93e68bfb 1054
bd81e77b 1055#define new_NOARENA(details) \
beeec492 1056 safemalloc((details)->body_size + (details)->offset)
bd81e77b 1057#define new_NOARENAZ(details) \
beeec492 1058 safecalloc((details)->body_size + (details)->offset, 1)
d2a0f284 1059
1e30fcd5
NC
1060void *
1061Perl_more_bodies (pTHX_ const svtype sv_type, const size_t body_size,
1062 const size_t arena_size)
d2a0f284 1063{
d2a0f284 1064 void ** const root = &PL_body_roots[sv_type];
99816f8d
NC
1065 struct arena_desc *adesc;
1066 struct arena_set *aroot = (struct arena_set *) PL_body_arenas;
1067 unsigned int curr;
d2a0f284
JC
1068 char *start;
1069 const char *end;
02982131 1070 const size_t good_arena_size = Perl_malloc_good_size(arena_size);
20b7effb
JH
1071#if defined(DEBUGGING) && defined(PERL_GLOBAL_STRUCT)
1072 dVAR;
1073#endif
a6098fe8 1074#if defined(DEBUGGING) && !defined(PERL_GLOBAL_STRUCT)
23e9d66c
NC
1075 static bool done_sanity_check;
1076
a6098fe8 1077 /* PERL_GLOBAL_STRUCT cannot coexist with global
0b2d3faa 1078 * variables like done_sanity_check. */
10666ae3 1079 if (!done_sanity_check) {
ea471437 1080 unsigned int i = SVt_LAST;
10666ae3
NC
1081
1082 done_sanity_check = TRUE;
1083
1084 while (i--)
1085 assert (bodies_by_type[i].type == i);
1086 }
1087#endif
1088
02982131 1089 assert(arena_size);
23e9d66c 1090
99816f8d
NC
1091 /* may need new arena-set to hold new arena */
1092 if (!aroot || aroot->curr >= aroot->set_size) {
1093 struct arena_set *newroot;
1094 Newxz(newroot, 1, struct arena_set);
1095 newroot->set_size = ARENAS_PER_SET;
1096 newroot->next = aroot;
1097 aroot = newroot;
1098 PL_body_arenas = (void *) newroot;
1099 DEBUG_m(PerlIO_printf(Perl_debug_log, "new arenaset %p\n", (void*)aroot));
1100 }
1101
1102 /* ok, now have arena-set with at least 1 empty/available arena-desc */
1103 curr = aroot->curr++;
1104 adesc = &(aroot->set[curr]);
1105 assert(!adesc->arena);
1106
1107 Newx(adesc->arena, good_arena_size, char);
1108 adesc->size = good_arena_size;
1109 adesc->utype = sv_type;
147e3846 1110 DEBUG_m(PerlIO_printf(Perl_debug_log, "arena %d added: %p size %" UVuf "\n",
99816f8d
NC
1111 curr, (void*)adesc->arena, (UV)good_arena_size));
1112
1113 start = (char *) adesc->arena;
d2a0f284 1114
29657bb6
NC
1115 /* Get the address of the byte after the end of the last body we can fit.
1116 Remember, this is integer division: */
02982131 1117 end = start + good_arena_size / body_size * body_size;
d2a0f284 1118
486ec47a 1119 /* computed count doesn't reflect the 1st slot reservation */
d8fca402
NC
1120#if defined(MYMALLOC) || defined(HAS_MALLOC_GOOD_SIZE)
1121 DEBUG_m(PerlIO_printf(Perl_debug_log,
1122 "arena %p end %p arena-size %d (from %d) type %d "
1123 "size %d ct %d\n",
02982131
NC
1124 (void*)start, (void*)end, (int)good_arena_size,
1125 (int)arena_size, sv_type, (int)body_size,
1126 (int)good_arena_size / (int)body_size));
d8fca402 1127#else
d2a0f284
JC
1128 DEBUG_m(PerlIO_printf(Perl_debug_log,
1129 "arena %p end %p arena-size %d type %d size %d ct %d\n",
6c9570dc 1130 (void*)start, (void*)end,
02982131
NC
1131 (int)arena_size, sv_type, (int)body_size,
1132 (int)good_arena_size / (int)body_size));
d8fca402 1133#endif
d2a0f284
JC
1134 *root = (void *)start;
1135
29657bb6
NC
1136 while (1) {
1137 /* Where the next body would start: */
d2a0f284 1138 char * const next = start + body_size;
29657bb6
NC
1139
1140 if (next >= end) {
1141 /* This is the last body: */
1142 assert(next == end);
1143
1144 *(void **)start = 0;
1145 return *root;
1146 }
1147
d2a0f284
JC
1148 *(void**) start = (void *)next;
1149 start = next;
1150 }
d2a0f284
JC
1151}
1152
1153/* grab a new thing from the free list, allocating more if necessary.
1154 The inline version is used for speed in hot routines, and the
1155 function using it serves the rest (unless PURIFY).
1156*/
1157#define new_body_inline(xpv, sv_type) \
1158 STMT_START { \
1159 void ** const r3wt = &PL_body_roots[sv_type]; \
11b79775 1160 xpv = (PTR_TBL_ENT_t*) (*((void **)(r3wt)) \
1e30fcd5 1161 ? *((void **)(r3wt)) : Perl_more_bodies(aTHX_ sv_type, \
02982131
NC
1162 bodies_by_type[sv_type].body_size,\
1163 bodies_by_type[sv_type].arena_size)); \
d2a0f284 1164 *(r3wt) = *(void**)(xpv); \
d2a0f284
JC
1165 } STMT_END
1166
1167#ifndef PURIFY
1168
1169STATIC void *
de37a194 1170S_new_body(pTHX_ const svtype sv_type)
d2a0f284 1171{
d2a0f284
JC
1172 void *xpv;
1173 new_body_inline(xpv, sv_type);
1174 return xpv;
1175}
1176
1177#endif
93e68bfb 1178
238b27b3
NC
1179static const struct body_details fake_rv =
1180 { 0, 0, 0, SVt_IV, FALSE, NONV, NOARENA, 0 };
1181
bd81e77b
NC
1182/*
1183=for apidoc sv_upgrade
93e68bfb 1184
bd81e77b
NC
1185Upgrade an SV to a more complex form. Generally adds a new body type to the
1186SV, then copies across as much information as possible from the old body.
9521ca61
FC
1187It croaks if the SV is already in a more complex form than requested. You
1188generally want to use the C<SvUPGRADE> macro wrapper, which checks the type
1189before calling C<sv_upgrade>, and hence does not croak. See also
fbe13c60 1190C<L</svtype>>.
93e68bfb 1191
bd81e77b 1192=cut
93e68bfb 1193*/
93e68bfb 1194
bd81e77b 1195void
5aaab254 1196Perl_sv_upgrade(pTHX_ SV *const sv, svtype new_type)
cac9b346 1197{
bd81e77b
NC
1198 void* old_body;
1199 void* new_body;
42d0e0b7 1200 const svtype old_type = SvTYPE(sv);
d2a0f284 1201 const struct body_details *new_type_details;
238b27b3 1202 const struct body_details *old_type_details
bd81e77b 1203 = bodies_by_type + old_type;
ed7df46e 1204 SV *referent = NULL;
cac9b346 1205
7918f24d
NC
1206 PERL_ARGS_ASSERT_SV_UPGRADE;
1207
1776cbe8
NC
1208 if (old_type == new_type)
1209 return;
1210
1211 /* This clause was purposefully added ahead of the early return above to
1212 the shared string hackery for (sort {$a <=> $b} keys %hash), with the
1213 inference by Nick I-S that it would fix other troublesome cases. See
1214 changes 7162, 7163 (f130fd4589cf5fbb24149cd4db4137c8326f49c1 and parent)
1215
1216 Given that shared hash key scalars are no longer PVIV, but PV, there is
1217 no longer need to unshare so as to free up the IVX slot for its proper
1218 purpose. So it's safe to move the early return earlier. */
1219
093085a8 1220 if (new_type > SVt_PVMG && SvIsCOW(sv)) {
bd81e77b
NC
1221 sv_force_normal_flags(sv, 0);
1222 }
cac9b346 1223
bd81e77b 1224 old_body = SvANY(sv);
de042e1d 1225
bd81e77b
NC
1226 /* Copying structures onto other structures that have been neatly zeroed
1227 has a subtle gotcha. Consider XPVMG
cac9b346 1228
bd81e77b
NC
1229 +------+------+------+------+------+-------+-------+
1230 | NV | CUR | LEN | IV | MAGIC | STASH |
1231 +------+------+------+------+------+-------+-------+
1232 0 4 8 12 16 20 24 28
645c22ef 1233
bd81e77b
NC
1234 where NVs are aligned to 8 bytes, so that sizeof that structure is
1235 actually 32 bytes long, with 4 bytes of padding at the end:
08742458 1236
bd81e77b
NC
1237 +------+------+------+------+------+-------+-------+------+
1238 | NV | CUR | LEN | IV | MAGIC | STASH | ??? |
1239 +------+------+------+------+------+-------+-------+------+
1240 0 4 8 12 16 20 24 28 32
08742458 1241
bd81e77b 1242 so what happens if you allocate memory for this structure:
30f9da9e 1243
bd81e77b
NC
1244 +------+------+------+------+------+-------+-------+------+------+...
1245 | NV | CUR | LEN | IV | MAGIC | STASH | GP | NAME |
1246 +------+------+------+------+------+-------+-------+------+------+...
1247 0 4 8 12 16 20 24 28 32 36
bfc44f79 1248
bd81e77b
NC
1249 zero it, then copy sizeof(XPVMG) bytes on top of it? Not quite what you
1250 expect, because you copy the area marked ??? onto GP. Now, ??? may have
1251 started out as zero once, but it's quite possible that it isn't. So now,
1252 rather than a nicely zeroed GP, you have it pointing somewhere random.
1253 Bugs ensue.
bfc44f79 1254
bd81e77b
NC
1255 (In fact, GP ends up pointing at a previous GP structure, because the
1256 principle cause of the padding in XPVMG getting garbage is a copy of
6c9e42f7
NC
1257 sizeof(XPVMG) bytes from a XPVGV structure in sv_unglob. Right now
1258 this happens to be moot because XPVGV has been re-ordered, with GP
1259 no longer after STASH)
30f9da9e 1260
bd81e77b
NC
1261 So we are careful and work out the size of used parts of all the
1262 structures. */
bfc44f79 1263
bd81e77b
NC
1264 switch (old_type) {
1265 case SVt_NULL:
1266 break;
1267 case SVt_IV:
4df7f6af 1268 if (SvROK(sv)) {
ed7df46e 1269 referent = SvRV(sv);
238b27b3
NC
1270 old_type_details = &fake_rv;
1271 if (new_type == SVt_NV)
1272 new_type = SVt_PVNV;
4df7f6af
NC
1273 } else {
1274 if (new_type < SVt_PVIV) {
1275 new_type = (new_type == SVt_NV)
1276 ? SVt_PVNV : SVt_PVIV;
1277 }
bd81e77b
NC
1278 }
1279 break;
1280 case SVt_NV:
1281 if (new_type < SVt_PVNV) {
1282 new_type = SVt_PVNV;
bd81e77b
NC
1283 }
1284 break;
bd81e77b
NC
1285 case SVt_PV:
1286 assert(new_type > SVt_PV);
6d59e610
LM
1287 STATIC_ASSERT_STMT(SVt_IV < SVt_PV);
1288 STATIC_ASSERT_STMT(SVt_NV < SVt_PV);
bd81e77b
NC
1289 break;
1290 case SVt_PVIV:
1291 break;
1292 case SVt_PVNV:
1293 break;
1294 case SVt_PVMG:
1295 /* Because the XPVMG of PL_mess_sv isn't allocated from the arena,
1296 there's no way that it can be safely upgraded, because perl.c
1297 expects to Safefree(SvANY(PL_mess_sv)) */
1298 assert(sv != PL_mess_sv);
bd81e77b
NC
1299 break;
1300 default:
2439e033 1301 if (UNLIKELY(old_type_details->cant_upgrade))
c81225bc
NC
1302 Perl_croak(aTHX_ "Can't upgrade %s (%" UVuf ") to %" UVuf,
1303 sv_reftype(sv, 0), (UV) old_type, (UV) new_type);
bd81e77b 1304 }
3376de98 1305
2439e033 1306 if (UNLIKELY(old_type > new_type))
3376de98
NC
1307 Perl_croak(aTHX_ "sv_upgrade from type %d down to type %d",
1308 (int)old_type, (int)new_type);
1309
2fa1109b 1310 new_type_details = bodies_by_type + new_type;
645c22ef 1311
bd81e77b
NC
1312 SvFLAGS(sv) &= ~SVTYPEMASK;
1313 SvFLAGS(sv) |= new_type;
932e9ff9 1314
ab4416c0
NC
1315 /* This can't happen, as SVt_NULL is <= all values of new_type, so one of
1316 the return statements above will have triggered. */
1317 assert (new_type != SVt_NULL);
bd81e77b 1318 switch (new_type) {
bd81e77b
NC
1319 case SVt_IV:
1320 assert(old_type == SVt_NULL);
dc6369ef 1321 SET_SVANY_FOR_BODYLESS_IV(sv);
bd81e77b
NC
1322 SvIV_set(sv, 0);
1323 return;
1324 case SVt_NV:
1325 assert(old_type == SVt_NULL);
5b306eef 1326#if NVSIZE <= IVSIZE
dc6369ef 1327 SET_SVANY_FOR_BODYLESS_NV(sv);
5b306eef 1328#else
bd81e77b 1329 SvANY(sv) = new_XNV();
5b306eef 1330#endif
bd81e77b
NC
1331 SvNV_set(sv, 0);
1332 return;
bd81e77b 1333 case SVt_PVHV:
bd81e77b 1334 case SVt_PVAV:
d2a0f284 1335 assert(new_type_details->body_size);
c1ae03ae
NC
1336
1337#ifndef PURIFY
1338 assert(new_type_details->arena);
d2a0f284 1339 assert(new_type_details->arena_size);
c1ae03ae 1340 /* This points to the start of the allocated area. */
d2a0f284
JC
1341 new_body_inline(new_body, new_type);
1342 Zero(new_body, new_type_details->body_size, char);
c1ae03ae
NC
1343 new_body = ((char *)new_body) - new_type_details->offset;
1344#else
1345 /* We always allocated the full length item with PURIFY. To do this
1346 we fake things so that arena is false for all 16 types.. */
1347 new_body = new_NOARENAZ(new_type_details);
1348#endif
1349 SvANY(sv) = new_body;
1350 if (new_type == SVt_PVAV) {
1351 AvMAX(sv) = -1;
1352 AvFILLp(sv) = -1;
1353 AvREAL_only(sv);
64484faa 1354 if (old_type_details->body_size) {
ac572bf4
NC
1355 AvALLOC(sv) = 0;
1356 } else {
1357 /* It will have been zeroed when the new body was allocated.
1358 Lets not write to it, in case it confuses a write-back
1359 cache. */
1360 }
78ac7dd9
NC
1361 } else {
1362 assert(!SvOK(sv));
1363 SvOK_off(sv);
1364#ifndef NODEFAULT_SHAREKEYS
1365 HvSHAREKEYS_on(sv); /* key-sharing on by default */
1366#endif
586fc6a3
SM
1367 /* start with PERL_HASH_DEFAULT_HvMAX+1 buckets: */
1368 HvMAX(sv) = PERL_HASH_DEFAULT_HvMAX;
c1ae03ae 1369 }
aeb18a1e 1370
bd81e77b
NC
1371 /* SVt_NULL isn't the only thing upgraded to AV or HV.
1372 The target created by newSVrv also is, and it can have magic.
1373 However, it never has SvPVX set.
1374 */
4df7f6af
NC
1375 if (old_type == SVt_IV) {
1376 assert(!SvROK(sv));
1377 } else if (old_type >= SVt_PV) {
bd81e77b
NC
1378 assert(SvPVX_const(sv) == 0);
1379 }
aeb18a1e 1380
bd81e77b 1381 if (old_type >= SVt_PVMG) {
e736a858 1382 SvMAGIC_set(sv, ((XPVMG*)old_body)->xmg_u.xmg_magic);
bd81e77b 1383 SvSTASH_set(sv, ((XPVMG*)old_body)->xmg_stash);
797c7171
NC
1384 } else {
1385 sv->sv_u.svu_array = NULL; /* or svu_hash */
bd81e77b
NC
1386 }
1387 break;
93e68bfb 1388
bd81e77b
NC
1389 case SVt_PVIV:
1390 /* XXX Is this still needed? Was it ever needed? Surely as there is
1391 no route from NV to PVIV, NOK can never be true */
1392 assert(!SvNOKp(sv));
1393 assert(!SvNOK(sv));
2b5060ae 1394 /* FALLTHROUGH */
bd81e77b
NC
1395 case SVt_PVIO:
1396 case SVt_PVFM:
bd81e77b
NC
1397 case SVt_PVGV:
1398 case SVt_PVCV:
1399 case SVt_PVLV:
d361b004 1400 case SVt_INVLIST:
12c45b25 1401 case SVt_REGEXP:
bd81e77b
NC
1402 case SVt_PVMG:
1403 case SVt_PVNV:
1404 case SVt_PV:
93e68bfb 1405
d2a0f284 1406 assert(new_type_details->body_size);
bd81e77b
NC
1407 /* We always allocated the full length item with PURIFY. To do this
1408 we fake things so that arena is false for all 16 types.. */
1409 if(new_type_details->arena) {
1410 /* This points to the start of the allocated area. */
d2a0f284
JC
1411 new_body_inline(new_body, new_type);
1412 Zero(new_body, new_type_details->body_size, char);
bd81e77b
NC
1413 new_body = ((char *)new_body) - new_type_details->offset;
1414 } else {
1415 new_body = new_NOARENAZ(new_type_details);
1416 }
1417 SvANY(sv) = new_body;
5e2fc214 1418
bd81e77b 1419 if (old_type_details->copy) {
f9ba3d20
NC
1420 /* There is now the potential for an upgrade from something without
1421 an offset (PVNV or PVMG) to something with one (PVCV, PVFM) */
1422 int offset = old_type_details->offset;
1423 int length = old_type_details->copy;
1424
1425 if (new_type_details->offset > old_type_details->offset) {
d4c19fe8 1426 const int difference
f9ba3d20
NC
1427 = new_type_details->offset - old_type_details->offset;
1428 offset += difference;
1429 length -= difference;
1430 }
1431 assert (length >= 0);
1432
1433 Copy((char *)old_body + offset, (char *)new_body + offset, length,
1434 char);
bd81e77b
NC
1435 }
1436
1437#ifndef NV_ZERO_IS_ALLBITS_ZERO
f2524eef 1438 /* If NV 0.0 is stores as all bits 0 then Zero() already creates a
e5ce394c
NC
1439 * correct 0.0 for us. Otherwise, if the old body didn't have an
1440 * NV slot, but the new one does, then we need to initialise the
1441 * freshly created NV slot with whatever the correct bit pattern is
1442 * for 0.0 */
e22a937e
NC
1443 if (old_type_details->zero_nv && !new_type_details->zero_nv
1444 && !isGV_with_GP(sv))
bd81e77b 1445 SvNV_set(sv, 0);
82048762 1446#endif
5e2fc214 1447
2439e033 1448 if (UNLIKELY(new_type == SVt_PVIO)) {
85dca89a 1449 IO * const io = MUTABLE_IO(sv);
d963bf01 1450 GV *iogv = gv_fetchpvs("IO::File::", GV_ADD, SVt_PVHV);
85dca89a
NC
1451
1452 SvOBJECT_on(io);
1453 /* Clear the stashcache because a new IO could overrule a package
1454 name */
103f5a36 1455 DEBUG_o(Perl_deb(aTHX_ "sv_upgrade clearing PL_stashcache\n"));
85dca89a
NC
1456 hv_clear(PL_stashcache);
1457
85dca89a 1458 SvSTASH_set(io, MUTABLE_HV(SvREFCNT_inc(GvHV(iogv))));
f2524eef 1459 IoPAGE_LEN(sv) = 60;
85dca89a 1460 }
df6b4bd5 1461 if (old_type < SVt_PV) {
ed7df46e 1462 /* referent will be NULL unless the old type was SVt_IV emulating
4df7f6af 1463 SVt_RV */
ed7df46e 1464 sv->sv_u.svu_rv = referent;
4df7f6af 1465 }
bd81e77b
NC
1466 break;
1467 default:
afd78fd5
JH
1468 Perl_croak(aTHX_ "panic: sv_upgrade to unknown type %lu",
1469 (unsigned long)new_type);
bd81e77b 1470 }
73171d91 1471
5b306eef
DD
1472 /* if this is zero, this is a body-less SVt_NULL, SVt_IV/SVt_RV,
1473 and sometimes SVt_NV */
1474 if (old_type_details->body_size) {
bd81e77b 1475#ifdef PURIFY
beeec492 1476 safefree(old_body);
bd81e77b 1477#else
bc786448
GG
1478 /* Note that there is an assumption that all bodies of types that
1479 can be upgraded came from arenas. Only the more complex non-
1480 upgradable types are allowed to be directly malloc()ed. */
1481 assert(old_type_details->arena);
bd81e77b
NC
1482 del_body((void*)((char*)old_body + old_type_details->offset),
1483 &PL_body_roots[old_type]);
1484#endif
1485 }
1486}
73171d91 1487
bd81e77b
NC
1488/*
1489=for apidoc sv_backoff
73171d91 1490
fde67290 1491Remove any string offset. You should normally use the C<SvOOK_off> macro
bd81e77b 1492wrapper instead.
73171d91 1493
bd81e77b 1494=cut
73171d91
NC
1495*/
1496
fa7a1e49
DD
1497/* prior to 5.000 stable, this function returned the new OOK-less SvFLAGS
1498 prior to 5.23.4 this function always returned 0
1499*/
1500
1501void
ddeaf645 1502Perl_sv_backoff(SV *const sv)
bd81e77b 1503{
69240efd 1504 STRLEN delta;
7a4bba22 1505 const char * const s = SvPVX_const(sv);
7918f24d
NC
1506
1507 PERL_ARGS_ASSERT_SV_BACKOFF;
7918f24d 1508
bd81e77b
NC
1509 assert(SvOOK(sv));
1510 assert(SvTYPE(sv) != SVt_PVHV);
1511 assert(SvTYPE(sv) != SVt_PVAV);
7a4bba22 1512
69240efd
NC
1513 SvOOK_offset(sv, delta);
1514
7a4bba22
NC
1515 SvLEN_set(sv, SvLEN(sv) + delta);
1516 SvPV_set(sv, SvPVX(sv) - delta);
bd81e77b 1517 SvFLAGS(sv) &= ~SVf_OOK;
fa7a1e49
DD
1518 Move(s, SvPVX(sv), SvCUR(sv)+1, char);
1519 return;
bd81e77b 1520}
73171d91 1521
03885497
DM
1522
1523/* forward declaration */
1524static void S_sv_uncow(pTHX_ SV * const sv, const U32 flags);
1525
1526
bd81e77b
NC
1527/*
1528=for apidoc sv_grow
73171d91 1529
bd81e77b
NC
1530Expands the character buffer in the SV. If necessary, uses C<sv_unref> and
1531upgrades the SV to C<SVt_PV>. Returns a pointer to the character buffer.
1532Use the C<SvGROW> wrapper instead.
93e68bfb 1533
bd81e77b
NC
1534=cut
1535*/
93e68bfb 1536
e0060e30 1537
bd81e77b 1538char *
5aaab254 1539Perl_sv_grow(pTHX_ SV *const sv, STRLEN newlen)
bd81e77b 1540{
eb578fdb 1541 char *s;
93e68bfb 1542
7918f24d
NC
1543 PERL_ARGS_ASSERT_SV_GROW;
1544
bd81e77b
NC
1545 if (SvROK(sv))
1546 sv_unref(sv);
1547 if (SvTYPE(sv) < SVt_PV) {
1548 sv_upgrade(sv, SVt_PV);
1549 s = SvPVX_mutable(sv);
1550 }
1551 else if (SvOOK(sv)) { /* pv is offset? */
1552 sv_backoff(sv);
1553 s = SvPVX_mutable(sv);
1554 if (newlen > SvLEN(sv))
1555 newlen += 10 * (newlen - SvCUR(sv)); /* avoid copy each time */
bd81e77b
NC
1556 }
1557 else
db2c6cb3 1558 {
e0060e30 1559 if (SvIsCOW(sv)) S_sv_uncow(aTHX_ sv, 0);
bd81e77b 1560 s = SvPVX_mutable(sv);
db2c6cb3 1561 }
aeb18a1e 1562
93c10d60 1563#ifdef PERL_COPY_ON_WRITE
cbcb2a16 1564 /* the new COW scheme uses SvPVX(sv)[SvLEN(sv)-1] (if spare)
3c239bea 1565 * to store the COW count. So in general, allocate one more byte than
cbcb2a16
DM
1566 * asked for, to make it likely this byte is always spare: and thus
1567 * make more strings COW-able.
fe546b38 1568 *
fa8f4f85
TC
1569 * Only increment if the allocation isn't MEM_SIZE_MAX,
1570 * otherwise it will wrap to 0.
1571 */
fe546b38 1572 if ( newlen != MEM_SIZE_MAX )
cbcb2a16
DM
1573 newlen++;
1574#endif
1575
ce861ea7
YO
1576#if defined(PERL_USE_MALLOC_SIZE) && defined(Perl_safesysmalloc_size)
1577#define PERL_UNWARANTED_CHUMMINESS_WITH_MALLOC
1578#endif
1579
bd81e77b 1580 if (newlen > SvLEN(sv)) { /* need more room? */
f1200559 1581 STRLEN minlen = SvCUR(sv);
3c239bea 1582 minlen += (minlen >> PERL_STRLEN_EXPAND_SHIFT) + 10;
f1200559
WH
1583 if (newlen < minlen)
1584 newlen = minlen;
ce861ea7 1585#ifndef PERL_UNWARANTED_CHUMMINESS_WITH_MALLOC
7c641603
KW
1586
1587 /* Don't round up on the first allocation, as odds are pretty good that
1588 * the initial request is accurate as to what is really needed */
ce861ea7 1589 if (SvLEN(sv)) {
9efda33a
TC
1590 STRLEN rounded = PERL_STRLEN_ROUNDUP(newlen);
1591 if (rounded > newlen)
1592 newlen = rounded;
ce861ea7 1593 }
bd81e77b 1594#endif
98653f18 1595 if (SvLEN(sv) && s) {
10edeb5d 1596 s = (char*)saferealloc(s, newlen);
bd81e77b
NC
1597 }
1598 else {
10edeb5d 1599 s = (char*)safemalloc(newlen);
bd81e77b 1600 if (SvPVX_const(sv) && SvCUR(sv)) {
0a5fcc38 1601 Move(SvPVX_const(sv), s, SvCUR(sv), char);
bd81e77b
NC
1602 }
1603 }
1604 SvPV_set(sv, s);
ce861ea7 1605#ifdef PERL_UNWARANTED_CHUMMINESS_WITH_MALLOC
98653f18
NC
1606 /* Do this here, do it once, do it right, and then we will never get
1607 called back into sv_grow() unless there really is some growing
1608 needed. */
ca7c1a29 1609 SvLEN_set(sv, Perl_safesysmalloc_size(s));
98653f18 1610#else
bd81e77b 1611 SvLEN_set(sv, newlen);
98653f18 1612#endif
bd81e77b
NC
1613 }
1614 return s;
1615}
aeb18a1e 1616
bd81e77b
NC
1617/*
1618=for apidoc sv_setiv
932e9ff9 1619
bd81e77b 1620Copies an integer into the given SV, upgrading first if necessary.
fbe13c60 1621Does not handle 'set' magic. See also C<L</sv_setiv_mg>>.
463ee0b2 1622
bd81e77b
NC
1623=cut
1624*/
463ee0b2 1625
bd81e77b 1626void
5aaab254 1627Perl_sv_setiv(pTHX_ SV *const sv, const IV i)
bd81e77b 1628{
7918f24d
NC
1629 PERL_ARGS_ASSERT_SV_SETIV;
1630
bd81e77b
NC
1631 SV_CHECK_THINKFIRST_COW_DROP(sv);
1632 switch (SvTYPE(sv)) {
1633 case SVt_NULL:
bd81e77b 1634 case SVt_NV:
3376de98 1635 sv_upgrade(sv, SVt_IV);
bd81e77b 1636 break;
bd81e77b
NC
1637 case SVt_PV:
1638 sv_upgrade(sv, SVt_PVIV);
1639 break;
463ee0b2 1640
bd81e77b 1641 case SVt_PVGV:
6e592b3a
BM
1642 if (!isGV_with_GP(sv))
1643 break;
2165bd23 1644 /* FALLTHROUGH */
bd81e77b
NC
1645 case SVt_PVAV:
1646 case SVt_PVHV:
1647 case SVt_PVCV:
1648 case SVt_PVFM:
1649 case SVt_PVIO:
22e74366 1650 /* diag_listed_as: Can't coerce %s to %s in %s */
bd81e77b
NC
1651 Perl_croak(aTHX_ "Can't coerce %s to integer in %s", sv_reftype(sv,0),
1652 OP_DESC(PL_op));
c9a0dcdc 1653 NOT_REACHED; /* NOTREACHED */
0103ca14 1654 break;
42d0e0b7 1655 default: NOOP;
bd81e77b
NC
1656 }
1657 (void)SvIOK_only(sv); /* validate number */
1658 SvIV_set(sv, i);
1659 SvTAINT(sv);
1660}
932e9ff9 1661
bd81e77b
NC
1662/*
1663=for apidoc sv_setiv_mg
d33b2eba 1664
bd81e77b 1665Like C<sv_setiv>, but also handles 'set' magic.
1c846c1f 1666
bd81e77b
NC
1667=cut
1668*/
d33b2eba 1669
bd81e77b 1670void
5aaab254 1671Perl_sv_setiv_mg(pTHX_ SV *const sv, const IV i)
bd81e77b 1672{
7918f24d
NC
1673 PERL_ARGS_ASSERT_SV_SETIV_MG;
1674
bd81e77b
NC
1675 sv_setiv(sv,i);
1676 SvSETMAGIC(sv);
1677}
727879eb 1678
bd81e77b
NC
1679/*
1680=for apidoc sv_setuv
d33b2eba 1681
bd81e77b 1682Copies an unsigned integer into the given SV, upgrading first if necessary.
fbe13c60 1683Does not handle 'set' magic. See also C<L</sv_setuv_mg>>.
9b94d1dd 1684
bd81e77b
NC
1685=cut
1686*/
d33b2eba 1687
bd81e77b 1688void
5aaab254 1689Perl_sv_setuv(pTHX_ SV *const sv, const UV u)
bd81e77b 1690{
7918f24d
NC
1691 PERL_ARGS_ASSERT_SV_SETUV;
1692
013abb9b
NC
1693 /* With the if statement to ensure that integers are stored as IVs whenever
1694 possible:
bd81e77b 1695 u=1.49 s=0.52 cu=72.49 cs=10.64 scripts=270 tests=20865
d33b2eba 1696
bd81e77b
NC
1697 without
1698 u=1.35 s=0.47 cu=73.45 cs=11.43 scripts=270 tests=20865
1c846c1f 1699
013abb9b
NC
1700 If you wish to remove the following if statement, so that this routine
1701 (and its callers) always return UVs, please benchmark to see what the
1702 effect is. Modern CPUs may be different. Or may not :-)
bd81e77b
NC
1703 */
1704 if (u <= (UV)IV_MAX) {
1705 sv_setiv(sv, (IV)u);
1706 return;
1707 }
1708 sv_setiv(sv, 0);
1709 SvIsUV_on(sv);
1710 SvUV_set(sv, u);
1711}
d33b2eba 1712
bd81e77b
NC
1713/*
1714=for apidoc sv_setuv_mg
727879eb 1715
bd81e77b 1716Like C<sv_setuv>, but also handles 'set' magic.
9b94d1dd 1717
bd81e77b
NC
1718=cut
1719*/
5e2fc214 1720
bd81e77b 1721void
5aaab254 1722Perl_sv_setuv_mg(pTHX_ SV *const sv, const UV u)
bd81e77b 1723{
7918f24d
NC
1724 PERL_ARGS_ASSERT_SV_SETUV_MG;
1725
bd81e77b
NC
1726 sv_setuv(sv,u);
1727 SvSETMAGIC(sv);
1728}
5e2fc214 1729
954c1994 1730/*
bd81e77b 1731=for apidoc sv_setnv
954c1994 1732
bd81e77b 1733Copies a double into the given SV, upgrading first if necessary.
fbe13c60 1734Does not handle 'set' magic. See also C<L</sv_setnv_mg>>.
954c1994
GS
1735
1736=cut
1737*/
1738
63f97190 1739void
5aaab254 1740Perl_sv_setnv(pTHX_ SV *const sv, const NV num)
79072805 1741{
7918f24d
NC
1742 PERL_ARGS_ASSERT_SV_SETNV;
1743
bd81e77b
NC
1744 SV_CHECK_THINKFIRST_COW_DROP(sv);
1745 switch (SvTYPE(sv)) {
79072805 1746 case SVt_NULL:
79072805 1747 case SVt_IV:
bd81e77b 1748 sv_upgrade(sv, SVt_NV);
79072805
LW
1749 break;
1750 case SVt_PV:
79072805 1751 case SVt_PVIV:
bd81e77b 1752 sv_upgrade(sv, SVt_PVNV);
79072805 1753 break;
bd4b1eb5 1754
bd4b1eb5 1755 case SVt_PVGV:
6e592b3a
BM
1756 if (!isGV_with_GP(sv))
1757 break;
2165bd23 1758 /* FALLTHROUGH */
bd81e77b
NC
1759 case SVt_PVAV:
1760 case SVt_PVHV:
79072805 1761 case SVt_PVCV:
bd81e77b
NC
1762 case SVt_PVFM:
1763 case SVt_PVIO:
22e74366 1764 /* diag_listed_as: Can't coerce %s to %s in %s */
bd81e77b 1765 Perl_croak(aTHX_ "Can't coerce %s to number in %s", sv_reftype(sv,0),
94bbb3f4 1766 OP_DESC(PL_op));
c9a0dcdc 1767 NOT_REACHED; /* NOTREACHED */
0103ca14 1768 break;
42d0e0b7 1769 default: NOOP;
2068cd4d 1770 }
bd81e77b
NC
1771 SvNV_set(sv, num);
1772 (void)SvNOK_only(sv); /* validate number */
1773 SvTAINT(sv);
79072805
LW
1774}
1775
645c22ef 1776/*
bd81e77b 1777=for apidoc sv_setnv_mg
645c22ef 1778
bd81e77b 1779Like C<sv_setnv>, but also handles 'set' magic.
645c22ef
DM
1780
1781=cut
1782*/
1783
bd81e77b 1784void
5aaab254 1785Perl_sv_setnv_mg(pTHX_ SV *const sv, const NV num)
79072805 1786{
7918f24d
NC
1787 PERL_ARGS_ASSERT_SV_SETNV_MG;
1788
bd81e77b
NC
1789 sv_setnv(sv,num);
1790 SvSETMAGIC(sv);
79072805
LW
1791}
1792
3f7602fa
TC
1793/* Return a cleaned-up, printable version of sv, for non-numeric, or
1794 * not incrementable warning display.
1795 * Originally part of S_not_a_number().
1796 * The return value may be != tmpbuf.
bd81e77b 1797 */
954c1994 1798
3f7602fa
TC
1799STATIC const char *
1800S_sv_display(pTHX_ SV *const sv, char *tmpbuf, STRLEN tmpbuf_size) {
1801 const char *pv;
94463019 1802
3f7602fa 1803 PERL_ARGS_ASSERT_SV_DISPLAY;
7918f24d 1804
94463019 1805 if (DO_UTF8(sv)) {
3f7602fa 1806 SV *dsv = newSVpvs_flags("", SVs_TEMP);
37b8cdd1 1807 pv = sv_uni_display(dsv, sv, 32, UNI_DISPLAY_ISPRINT);
94463019
JH
1808 } else {
1809 char *d = tmpbuf;
3f7602fa 1810 const char * const limit = tmpbuf + tmpbuf_size - 8;
94463019
JH
1811 /* each *s can expand to 4 chars + "...\0",
1812 i.e. need room for 8 chars */
ecdeb87c 1813
00b6aa41
AL
1814 const char *s = SvPVX_const(sv);
1815 const char * const end = s + SvCUR(sv);
1816 for ( ; s < end && d < limit; s++ ) {
94463019 1817 int ch = *s & 0xFF;
bd27cf70 1818 if (! isASCII(ch) && !isPRINT_LC(ch)) {
94463019
JH
1819 *d++ = 'M';
1820 *d++ = '-';
bd27cf70
KW
1821
1822 /* Map to ASCII "equivalent" of Latin1 */
1823 ch = LATIN1_TO_NATIVE(NATIVE_TO_LATIN1(ch) & 127);
94463019
JH
1824 }
1825 if (ch == '\n') {
1826 *d++ = '\\';
1827 *d++ = 'n';
1828 }
1829 else if (ch == '\r') {
1830 *d++ = '\\';
1831 *d++ = 'r';
1832 }
1833 else if (ch == '\f') {
1834 *d++ = '\\';
1835 *d++ = 'f';
1836 }
1837 else if (ch == '\\') {
1838 *d++ = '\\';
1839 *d++ = '\\';
1840 }
1841 else if (ch == '\0') {
1842 *d++ = '\\';
1843 *d++ = '0';
1844 }
1845 else if (isPRINT_LC(ch))
1846 *d++ = ch;
1847 else {
1848 *d++ = '^';
1849 *d++ = toCTRL(ch);
1850 }
1851 }
1852 if (s < end) {
1853 *d++ = '.';
1854 *d++ = '.';
1855 *d++ = '.';
1856 }
1857 *d = '\0';
1858 pv = tmpbuf;
a0d0e21e 1859 }
a0d0e21e 1860
3f7602fa
TC
1861 return pv;
1862}
1863
1864/* Print an "isn't numeric" warning, using a cleaned-up,
1865 * printable version of the offending string
1866 */
1867
1868STATIC void
1869S_not_a_number(pTHX_ SV *const sv)
1870{
3f7602fa
TC
1871 char tmpbuf[64];
1872 const char *pv;
1873
1874 PERL_ARGS_ASSERT_NOT_A_NUMBER;
1875
1876 pv = sv_display(sv, tmpbuf, sizeof(tmpbuf));
1877
533c011a 1878 if (PL_op)
9014280d 1879 Perl_warner(aTHX_ packWARN(WARN_NUMERIC),
734856a2 1880 /* diag_listed_as: Argument "%s" isn't numeric%s */
94463019
JH
1881 "Argument \"%s\" isn't numeric in %s", pv,
1882 OP_DESC(PL_op));
a0d0e21e 1883 else
9014280d 1884 Perl_warner(aTHX_ packWARN(WARN_NUMERIC),
734856a2 1885 /* diag_listed_as: Argument "%s" isn't numeric%s */
94463019 1886 "Argument \"%s\" isn't numeric", pv);
a0d0e21e
LW
1887}
1888
3f7602fa
TC
1889STATIC void
1890S_not_incrementable(pTHX_ SV *const sv) {
3f7602fa
TC
1891 char tmpbuf[64];
1892 const char *pv;
1893
1894 PERL_ARGS_ASSERT_NOT_INCREMENTABLE;
1895
1896 pv = sv_display(sv, tmpbuf, sizeof(tmpbuf));
1897
1898 Perl_warner(aTHX_ packWARN(WARN_NUMERIC),
1899 "Argument \"%s\" treated as 0 in increment (++)", pv);
1900}
1901
c2988b20
NC
1902/*
1903=for apidoc looks_like_number
1904
645c22ef
DM
1905Test if the content of an SV looks like a number (or is a number).
1906C<Inf> and C<Infinity> are treated as numbers (so will not issue a
796b6530 1907non-numeric warning), even if your C<atof()> doesn't grok them. Get-magic is
f52e41ad 1908ignored.
c2988b20
NC
1909
1910=cut
1911*/
1912
1913I32
aad570aa 1914Perl_looks_like_number(pTHX_ SV *const sv)
c2988b20 1915{
eb578fdb 1916 const char *sbegin;
c2988b20 1917 STRLEN len;
ea2485eb 1918 int numtype;
c2988b20 1919
7918f24d
NC
1920 PERL_ARGS_ASSERT_LOOKS_LIKE_NUMBER;
1921
f52e41ad
FC
1922 if (SvPOK(sv) || SvPOKp(sv)) {
1923 sbegin = SvPV_nomg_const(sv, len);
c2988b20 1924 }
c2988b20 1925 else
e0ab1c0e 1926 return SvFLAGS(sv) & (SVf_NOK|SVp_NOK|SVf_IOK|SVp_IOK);
ea2485eb
JH
1927 numtype = grok_number(sbegin, len, NULL);
1928 return ((numtype & IS_NUMBER_TRAILING)) ? 0 : numtype;
c2988b20 1929}
25da4f38 1930
19f6321d
NC
1931STATIC bool
1932S_glob_2number(pTHX_ GV * const gv)
180488f8 1933{
7918f24d
NC
1934 PERL_ARGS_ASSERT_GLOB_2NUMBER;
1935
675c862f
AL
1936 /* We know that all GVs stringify to something that is not-a-number,
1937 so no need to test that. */
1938 if (ckWARN(WARN_NUMERIC))
8e629ff4
FC
1939 {
1940 SV *const buffer = sv_newmortal();
1941 gv_efullname3(buffer, gv, "*");
675c862f 1942 not_a_number(buffer);
8e629ff4 1943 }
675c862f
AL
1944 /* We just want something true to return, so that S_sv_2iuv_common
1945 can tail call us and return true. */
19f6321d 1946 return TRUE;
675c862f
AL
1947}
1948
25da4f38
IZ
1949/* Actually, ISO C leaves conversion of UV to IV undefined, but
1950 until proven guilty, assume that things are not that bad... */
1951
645c22ef
DM
1952/*
1953 NV_PRESERVES_UV:
1954
1955 As 64 bit platforms often have an NV that doesn't preserve all bits of
28e5dec8
JH
1956 an IV (an assumption perl has been based on to date) it becomes necessary
1957 to remove the assumption that the NV always carries enough precision to
1958 recreate the IV whenever needed, and that the NV is the canonical form.
1959 Instead, IV/UV and NV need to be given equal rights. So as to not lose
645c22ef 1960 precision as a side effect of conversion (which would lead to insanity
28e5dec8 1961 and the dragon(s) in t/op/numconvert.t getting very angry) the intent is
8a4a3196
KW
1962 1) to distinguish between IV/UV/NV slots that have a valid conversion cached
1963 where precision was lost, and IV/UV/NV slots that have a valid conversion
1964 which has lost no precision
645c22ef 1965 2) to ensure that if a numeric conversion to one form is requested that
28e5dec8
JH
1966 would lose precision, the precise conversion (or differently
1967 imprecise conversion) is also performed and cached, to prevent
1968 requests for different numeric formats on the same SV causing
1969 lossy conversion chains. (lossless conversion chains are perfectly
1970 acceptable (still))
1971
1972
1973 flags are used:
1974 SvIOKp is true if the IV slot contains a valid value
1975 SvIOK is true only if the IV value is accurate (UV if SvIOK_UV true)
1976 SvNOKp is true if the NV slot contains a valid value
1977 SvNOK is true only if the NV value is accurate
1978
1979 so
645c22ef 1980 while converting from PV to NV, check to see if converting that NV to an
28e5dec8
JH
1981 IV(or UV) would lose accuracy over a direct conversion from PV to
1982 IV(or UV). If it would, cache both conversions, return NV, but mark
1983 SV as IOK NOKp (ie not NOK).
1984
645c22ef 1985 While converting from PV to IV, check to see if converting that IV to an
28e5dec8
JH
1986 NV would lose accuracy over a direct conversion from PV to NV. If it
1987 would, cache both conversions, flag similarly.
1988
1989 Before, the SV value "3.2" could become NV=3.2 IV=3 NOK, IOK quite
1990 correctly because if IV & NV were set NV *always* overruled.
645c22ef
DM
1991 Now, "3.2" will become NV=3.2 IV=3 NOK, IOKp, because the flag's meaning
1992 changes - now IV and NV together means that the two are interchangeable:
28e5dec8 1993 SvIVX == (IV) SvNVX && SvNVX == (NV) SvIVX;
d460ef45 1994
645c22ef
DM
1995 The benefit of this is that operations such as pp_add know that if
1996 SvIOK is true for both left and right operands, then integer addition
1997 can be used instead of floating point (for cases where the result won't
1998 overflow). Before, floating point was always used, which could lead to
28e5dec8
JH
1999 loss of precision compared with integer addition.
2000
2001 * making IV and NV equal status should make maths accurate on 64 bit
2002 platforms
2003 * may speed up maths somewhat if pp_add and friends start to use
645c22ef 2004 integers when possible instead of fp. (Hopefully the overhead in
28e5dec8
JH
2005 looking for SvIOK and checking for overflow will not outweigh the
2006 fp to integer speedup)
2007 * will slow down integer operations (callers of SvIV) on "inaccurate"
2008 values, as the change from SvIOK to SvIOKp will cause a call into
2009 sv_2iv each time rather than a macro access direct to the IV slot
2010 * should speed up number->string conversion on integers as IV is
645c22ef 2011 favoured when IV and NV are equally accurate
28e5dec8
JH
2012
2013 ####################################################################
645c22ef
DM
2014 You had better be using SvIOK_notUV if you want an IV for arithmetic:
2015 SvIOK is true if (IV or UV), so you might be getting (IV)SvUV.
2016 On the other hand, SvUOK is true iff UV.
28e5dec8
JH
2017 ####################################################################
2018
645c22ef 2019 Your mileage will vary depending your CPU's relative fp to integer
28e5dec8
JH
2020 performance ratio.
2021*/
2022
2023#ifndef NV_PRESERVES_UV
645c22ef
DM
2024# define IS_NUMBER_UNDERFLOW_IV 1
2025# define IS_NUMBER_UNDERFLOW_UV 2
2026# define IS_NUMBER_IV_AND_UV 2
2027# define IS_NUMBER_OVERFLOW_IV 4
2028# define IS_NUMBER_OVERFLOW_UV 5
2029
2030/* sv_2iuv_non_preserve(): private routine for use by sv_2iv() and sv_2uv() */
28e5dec8
JH
2031
2032/* For sv_2nv these three cases are "SvNOK and don't bother casting" */
2033STATIC int
5aaab254 2034S_sv_2iuv_non_preserve(pTHX_ SV *const sv
47031da6
NC
2035# ifdef DEBUGGING
2036 , I32 numtype
2037# endif
2038 )
28e5dec8 2039{
7918f24d 2040 PERL_ARGS_ASSERT_SV_2IUV_NON_PRESERVE;
23491f1d 2041 PERL_UNUSED_CONTEXT;
7918f24d 2042
147e3846 2043 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
2044 if (SvNVX(sv) < (NV)IV_MIN) {
2045 (void)SvIOKp_on(sv);
2046 (void)SvNOK_on(sv);
45977657 2047 SvIV_set(sv, IV_MIN);
28e5dec8
JH
2048 return IS_NUMBER_UNDERFLOW_IV;
2049 }
2050 if (SvNVX(sv) > (NV)UV_MAX) {
2051 (void)SvIOKp_on(sv);
2052 (void)SvNOK_on(sv);
2053 SvIsUV_on(sv);
607fa7f2 2054 SvUV_set(sv, UV_MAX);
28e5dec8
JH
2055 return IS_NUMBER_OVERFLOW_UV;
2056 }
c2988b20
NC
2057 (void)SvIOKp_on(sv);
2058 (void)SvNOK_on(sv);
2059 /* Can't use strtol etc to convert this string. (See truth table in
2060 sv_2iv */
2061 if (SvNVX(sv) <= (UV)IV_MAX) {
45977657 2062 SvIV_set(sv, I_V(SvNVX(sv)));
659c4b96 2063 if ((NV)(SvIVX(sv)) == SvNVX(sv)) {
c2988b20
NC
2064 SvIOK_on(sv); /* Integer is precise. NOK, IOK */
2065 } else {
2066 /* Integer is imprecise. NOK, IOKp */
2067 }
2068 return SvNVX(sv) < 0 ? IS_NUMBER_UNDERFLOW_UV : IS_NUMBER_IV_AND_UV;
2069 }
2070 SvIsUV_on(sv);
607fa7f2 2071 SvUV_set(sv, U_V(SvNVX(sv)));
659c4b96 2072 if ((NV)(SvUVX(sv)) == SvNVX(sv)) {
c2988b20
NC
2073 if (SvUVX(sv) == UV_MAX) {
2074 /* As we know that NVs don't preserve UVs, UV_MAX cannot
2075 possibly be preserved by NV. Hence, it must be overflow.
2076 NOK, IOKp */
2077 return IS_NUMBER_OVERFLOW_UV;
2078 }
2079 SvIOK_on(sv); /* Integer is precise. NOK, UOK */
2080 } else {
2081 /* Integer is imprecise. NOK, IOKp */
28e5dec8 2082 }
c2988b20 2083 return IS_NUMBER_OVERFLOW_IV;
28e5dec8 2084}
645c22ef
DM
2085#endif /* !NV_PRESERVES_UV*/
2086
a13f4dff 2087/* If numtype is infnan, set the NV of the sv accordingly.
5564cd7f 2088 * If numtype is anything else, try setting the NV using Atof(PV). */
a13f4dff 2089static void
3823048b 2090S_sv_setnv(pTHX_ SV* sv, int numtype)
a13f4dff 2091{
07925c5e 2092 bool pok = cBOOL(SvPOK(sv));
5564cd7f 2093 bool nok = FALSE;
a7157111 2094#ifdef NV_INF
a13f4dff
JH
2095 if ((numtype & IS_NUMBER_INFINITY)) {
2096 SvNV_set(sv, (numtype & IS_NUMBER_NEG) ? -NV_INF : NV_INF);
5564cd7f 2097 nok = TRUE;
a7157111
JH
2098 } else
2099#endif
2100#ifdef NV_NAN
2101 if ((numtype & IS_NUMBER_NAN)) {
3823048b 2102 SvNV_set(sv, NV_NAN);
d48bd569 2103 nok = TRUE;
a7157111
JH
2104 } else
2105#endif
2106 if (pok) {
a13f4dff 2107 SvNV_set(sv, Atof(SvPVX_const(sv)));
d48bd569
JH
2108 /* Purposefully no true nok here, since we don't want to blow
2109 * away the possible IOK/UV of an existing sv. */
2110 }
5564cd7f 2111 if (nok) {
d48bd569 2112 SvNOK_only(sv); /* No IV or UV please, this is pure infnan. */
5564cd7f
JH
2113 if (pok)
2114 SvPOK_on(sv); /* PV is okay, though. */
2115 }
a13f4dff
JH
2116}
2117
af359546 2118STATIC bool
7918f24d
NC
2119S_sv_2iuv_common(pTHX_ SV *const sv)
2120{
7918f24d
NC
2121 PERL_ARGS_ASSERT_SV_2IUV_COMMON;
2122
af359546 2123 if (SvNOKp(sv)) {
28e5dec8
JH
2124 /* erm. not sure. *should* never get NOKp (without NOK) from sv_2nv
2125 * without also getting a cached IV/UV from it at the same time
2126 * (ie PV->NV conversion should detect loss of accuracy and cache
af359546
NC
2127 * IV or UV at same time to avoid this. */
2128 /* IV-over-UV optimisation - choose to cache IV if possible */
25da4f38
IZ
2129
2130 if (SvTYPE(sv) == SVt_NV)
2131 sv_upgrade(sv, SVt_PVNV);
2132
28e5dec8
JH
2133 (void)SvIOKp_on(sv); /* Must do this first, to clear any SvOOK */
2134 /* < not <= as for NV doesn't preserve UV, ((NV)IV_MAX+1) will almost
2135 certainly cast into the IV range at IV_MAX, whereas the correct
2136 answer is the UV IV_MAX +1. Hence < ensures that dodgy boundary
2137 cases go to UV */
e91de695
JH
2138#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
2139 if (Perl_isnan(SvNVX(sv))) {
2140 SvUV_set(sv, 0);
2141 SvIsUV_on(sv);
2142 return FALSE;
2143 }
2144#endif
28e5dec8 2145 if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
45977657 2146 SvIV_set(sv, I_V(SvNVX(sv)));
659c4b96 2147 if (SvNVX(sv) == (NV) SvIVX(sv)
28e5dec8 2148#ifndef NV_PRESERVES_UV
53e2bfb7 2149 && SvIVX(sv) != IV_MIN /* avoid negating IV_MIN below */
28e5dec8
JH
2150 && (((UV)1 << NV_PRESERVES_UV_BITS) >
2151 (UV)(SvIVX(sv) > 0 ? SvIVX(sv) : -SvIVX(sv)))
2152 /* Don't flag it as "accurately an integer" if the number
2153 came from a (by definition imprecise) NV operation, and
2154 we're outside the range of NV integer precision */
2155#endif
2156 ) {
a43d94f2
NC
2157 if (SvNOK(sv))
2158 SvIOK_on(sv); /* Can this go wrong with rounding? NWC */
2159 else {
2160 /* scalar has trailing garbage, eg "42a" */
2161 }
28e5dec8 2162 DEBUG_c(PerlIO_printf(Perl_debug_log,
147e3846 2163 "0x%" UVxf " iv(%" NVgf " => %" IVdf ") (precise)\n",
28e5dec8
JH
2164 PTR2UV(sv),
2165 SvNVX(sv),
2166 SvIVX(sv)));
2167
2168 } else {
2169 /* IV not precise. No need to convert from PV, as NV
2170 conversion would already have cached IV if it detected
2171 that PV->IV would be better than PV->NV->IV
2172 flags already correct - don't set public IOK. */
2173 DEBUG_c(PerlIO_printf(Perl_debug_log,
147e3846 2174 "0x%" UVxf " iv(%" NVgf " => %" IVdf ") (imprecise)\n",
28e5dec8
JH
2175 PTR2UV(sv),
2176 SvNVX(sv),
2177 SvIVX(sv)));
2178 }
2179 /* Can the above go wrong if SvIVX == IV_MIN and SvNVX < IV_MIN,
2180 but the cast (NV)IV_MIN rounds to a the value less (more
2181 negative) than IV_MIN which happens to be equal to SvNVX ??
2182 Analogous to 0xFFFFFFFFFFFFFFFF rounding up to NV (2**64) and
2183 NV rounding back to 0xFFFFFFFFFFFFFFFF, so UVX == UV(NVX) and
2184 (NV)UVX == NVX are both true, but the values differ. :-(
2185 Hopefully for 2s complement IV_MIN is something like
2186 0x8000000000000000 which will be exact. NWC */
d460ef45 2187 }
25da4f38 2188 else {
607fa7f2 2189 SvUV_set(sv, U_V(SvNVX(sv)));
28e5dec8 2190 if (
659c4b96 2191 (SvNVX(sv) == (NV) SvUVX(sv))
28e5dec8
JH
2192#ifndef NV_PRESERVES_UV
2193 /* Make sure it's not 0xFFFFFFFFFFFFFFFF */
2194 /*&& (SvUVX(sv) != UV_MAX) irrelevant with code below */
2195 && (((UV)1 << NV_PRESERVES_UV_BITS) > SvUVX(sv))
2196 /* Don't flag it as "accurately an integer" if the number
2197 came from a (by definition imprecise) NV operation, and
2198 we're outside the range of NV integer precision */
2199#endif
a43d94f2 2200 && SvNOK(sv)
28e5dec8
JH
2201 )
2202 SvIOK_on(sv);
25da4f38 2203 SvIsUV_on(sv);
1c846c1f 2204 DEBUG_c(PerlIO_printf(Perl_debug_log,
147e3846 2205 "0x%" UVxf " 2iv(%" UVuf " => %" IVdf ") (as unsigned)\n",
56431972 2206 PTR2UV(sv),
57def98f
JH
2207 SvUVX(sv),
2208 SvUVX(sv)));
25da4f38 2209 }
748a9306 2210 }
cd84013a 2211 else if (SvPOKp(sv)) {
c2988b20 2212 UV value;
80e5abf2
DM
2213 int numtype;
2214 const char *s = SvPVX_const(sv);
2215 const STRLEN cur = SvCUR(sv);
2216
2217 /* short-cut for a single digit string like "1" */
2218
2219 if (cur == 1) {
2220 char c = *s;
2221 if (isDIGIT(c)) {
2222 if (SvTYPE(sv) < SVt_PVIV)
2223 sv_upgrade(sv, SVt_PVIV);
2224 (void)SvIOK_on(sv);
2225 SvIV_set(sv, (IV)(c - '0'));
2226 return FALSE;
2227 }
2228 }
2229
2230 numtype = grok_number(s, cur, &value);
af359546 2231 /* We want to avoid a possible problem when we cache an IV/ a UV which
25da4f38 2232 may be later translated to an NV, and the resulting NV is not
c2988b20
NC
2233 the same as the direct translation of the initial string
2234 (eg 123.456 can shortcut to the IV 123 with atol(), but we must
2235 be careful to ensure that the value with the .456 is around if the
2236 NV value is requested in the future).
1c846c1f 2237
af359546 2238 This means that if we cache such an IV/a UV, we need to cache the
25da4f38 2239 NV as well. Moreover, we trade speed for space, and do not
28e5dec8 2240 cache the NV if we are sure it's not needed.
25da4f38 2241 */
16b7a9a4 2242
c2988b20
NC
2243 /* SVt_PVNV is one higher than SVt_PVIV, hence this order */
2244 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2245 == IS_NUMBER_IN_UV) {
5e045b90 2246 /* It's definitely an integer, only upgrade to PVIV */
28e5dec8
JH
2247 if (SvTYPE(sv) < SVt_PVIV)
2248 sv_upgrade(sv, SVt_PVIV);
f7bbb42a 2249 (void)SvIOK_on(sv);
c2988b20
NC
2250 } else if (SvTYPE(sv) < SVt_PVNV)
2251 sv_upgrade(sv, SVt_PVNV);
28e5dec8 2252
a13f4dff 2253 if ((numtype & (IS_NUMBER_INFINITY | IS_NUMBER_NAN))) {
75a57a38 2254 if (ckWARN(WARN_NUMERIC) && ((numtype & IS_NUMBER_TRAILING)))
6b322424 2255 not_a_number(sv);
3823048b 2256 S_sv_setnv(aTHX_ sv, numtype);
a13f4dff
JH
2257 return FALSE;
2258 }
2259
f2524eef 2260 /* If NVs preserve UVs then we only use the UV value if we know that
c2988b20
NC
2261 we aren't going to call atof() below. If NVs don't preserve UVs
2262 then the value returned may have more precision than atof() will
2263 return, even though value isn't perfectly accurate. */
2264 if ((numtype & (IS_NUMBER_IN_UV
2265#ifdef NV_PRESERVES_UV
2266 | IS_NUMBER_NOT_INT
2267#endif
2268 )) == IS_NUMBER_IN_UV) {
2269 /* This won't turn off the public IOK flag if it was set above */
2270 (void)SvIOKp_on(sv);
2271
2272 if (!(numtype & IS_NUMBER_NEG)) {
2273 /* positive */;
2274 if (value <= (UV)IV_MAX) {
45977657 2275 SvIV_set(sv, (IV)value);
c2988b20 2276 } else {
af359546 2277 /* it didn't overflow, and it was positive. */
607fa7f2 2278 SvUV_set(sv, value);
c2988b20
NC
2279 SvIsUV_on(sv);
2280 }
2281 } else {
2282 /* 2s complement assumption */
2283 if (value <= (UV)IV_MIN) {
53e2bfb7
DM
2284 SvIV_set(sv, value == (UV)IV_MIN
2285 ? IV_MIN : -(IV)value);
c2988b20
NC
2286 } else {
2287 /* Too negative for an IV. This is a double upgrade, but
d1be9408 2288 I'm assuming it will be rare. */
c2988b20
NC
2289 if (SvTYPE(sv) < SVt_PVNV)
2290 sv_upgrade(sv, SVt_PVNV);
2291 SvNOK_on(sv);
2292 SvIOK_off(sv);
2293 SvIOKp_on(sv);
9d6ce603 2294 SvNV_set(sv, -(NV)value);
45977657 2295 SvIV_set(sv, IV_MIN);
c2988b20
NC
2296 }
2297 }
2298 }
2299 /* For !NV_PRESERVES_UV and IS_NUMBER_IN_UV and IS_NUMBER_NOT_INT we
2300 will be in the previous block to set the IV slot, and the next
2301 block to set the NV slot. So no else here. */
2302
2303 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2304 != IS_NUMBER_IN_UV) {
2305 /* It wasn't an (integer that doesn't overflow the UV). */
3823048b 2306 S_sv_setnv(aTHX_ sv, numtype);
28e5dec8 2307
c2988b20
NC
2308 if (! numtype && ckWARN(WARN_NUMERIC))
2309 not_a_number(sv);
28e5dec8 2310
147e3846 2311 DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2iv(%" NVgf ")\n",
c2988b20 2312 PTR2UV(sv), SvNVX(sv)));
28e5dec8 2313
28e5dec8 2314#ifdef NV_PRESERVES_UV
af359546
NC
2315 (void)SvIOKp_on(sv);
2316 (void)SvNOK_on(sv);
e91de695
JH
2317#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
2318 if (Perl_isnan(SvNVX(sv))) {
2319 SvUV_set(sv, 0);
2320 SvIsUV_on(sv);
2321 return FALSE;
2322 }
2323#endif
af359546
NC
2324 if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
2325 SvIV_set(sv, I_V(SvNVX(sv)));
2326 if ((NV)(SvIVX(sv)) == SvNVX(sv)) {
2327 SvIOK_on(sv);
2328 } else {
6f207bd3 2329 NOOP; /* Integer is imprecise. NOK, IOKp */
af359546
NC
2330 }
2331 /* UV will not work better than IV */
2332 } else {
2333 if (SvNVX(sv) > (NV)UV_MAX) {
2334 SvIsUV_on(sv);
2335 /* Integer is inaccurate. NOK, IOKp, is UV */
2336 SvUV_set(sv, UV_MAX);
af359546
NC
2337 } else {
2338 SvUV_set(sv, U_V(SvNVX(sv)));
2339 /* 0xFFFFFFFFFFFFFFFF not an issue in here, NVs
2340 NV preservse UV so can do correct comparison. */
2341 if ((NV)(SvUVX(sv)) == SvNVX(sv)) {
2342 SvIOK_on(sv);
af359546 2343 } else {
6f207bd3 2344 NOOP; /* Integer is imprecise. NOK, IOKp, is UV */
af359546
NC
2345 }
2346 }
4b0c9573 2347 SvIsUV_on(sv);
af359546 2348 }
28e5dec8 2349#else /* NV_PRESERVES_UV */
c2988b20
NC
2350 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2351 == (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT)) {
af359546 2352 /* The IV/UV slot will have been set from value returned by
c2988b20
NC
2353 grok_number above. The NV slot has just been set using
2354 Atof. */
560b0c46 2355 SvNOK_on(sv);
c2988b20
NC
2356 assert (SvIOKp(sv));
2357 } else {
2358 if (((UV)1 << NV_PRESERVES_UV_BITS) >
2359 U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))) {
2360 /* Small enough to preserve all bits. */
2361 (void)SvIOKp_on(sv);
2362 SvNOK_on(sv);
45977657 2363 SvIV_set(sv, I_V(SvNVX(sv)));
659c4b96 2364 if ((NV)(SvIVX(sv)) == SvNVX(sv))
c2988b20
NC
2365 SvIOK_on(sv);
2366 /* Assumption: first non-preserved integer is < IV_MAX,
2367 this NV is in the preserved range, therefore: */
2368 if (!(U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))
2369 < (UV)IV_MAX)) {
147e3846 2370 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
2371 }
2372 } else {
2373 /* IN_UV NOT_INT
2374 0 0 already failed to read UV.
2375 0 1 already failed to read UV.
2376 1 0 you won't get here in this case. IV/UV
2377 slot set, public IOK, Atof() unneeded.
2378 1 1 already read UV.
2379 so there's no point in sv_2iuv_non_preserve() attempting
2380 to use atol, strtol, strtoul etc. */
47031da6 2381# ifdef DEBUGGING
40a17c4c 2382 sv_2iuv_non_preserve (sv, numtype);
47031da6
NC
2383# else
2384 sv_2iuv_non_preserve (sv);
2385# endif
c2988b20
NC
2386 }
2387 }
28e5dec8 2388#endif /* NV_PRESERVES_UV */
a43d94f2
NC
2389 /* It might be more code efficient to go through the entire logic above
2390 and conditionally set with SvIOKp_on() rather than SvIOK(), but it
2391 gets complex and potentially buggy, so more programmer efficient
2392 to do it this way, by turning off the public flags: */
2393 if (!numtype)
2394 SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK);
25da4f38 2395 }
af359546
NC
2396 }
2397 else {
675c862f 2398 if (isGV_with_GP(sv))
159b6efe 2399 return glob_2number(MUTABLE_GV(sv));
180488f8 2400
4f62cd62 2401 if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
af359546 2402 report_uninit(sv);
25da4f38
IZ
2403 if (SvTYPE(sv) < SVt_IV)
2404 /* Typically the caller expects that sv_any is not NULL now. */
2405 sv_upgrade(sv, SVt_IV);
af359546
NC
2406 /* Return 0 from the caller. */
2407 return TRUE;
2408 }
2409 return FALSE;
2410}
2411
2412/*
2413=for apidoc sv_2iv_flags
2414
2415Return the integer value of an SV, doing any necessary string
c5608a1f 2416conversion. If C<flags> has the C<SV_GMAGIC> bit set, does an C<mg_get()> first.
af359546
NC
2417Normally used via the C<SvIV(sv)> and C<SvIVx(sv)> macros.
2418
2419=cut
2420*/
2421
2422IV
5aaab254 2423Perl_sv_2iv_flags(pTHX_ SV *const sv, const I32 flags)
af359546 2424{
1061065f 2425 PERL_ARGS_ASSERT_SV_2IV_FLAGS;
4bac9ae4 2426
217f6fa3
FC
2427 assert (SvTYPE(sv) != SVt_PVAV && SvTYPE(sv) != SVt_PVHV
2428 && SvTYPE(sv) != SVt_PVFM);
2429
4bac9ae4
CS
2430 if (SvGMAGICAL(sv) && (flags & SV_GMAGIC))
2431 mg_get(sv);
2432
2433 if (SvROK(sv)) {
2434 if (SvAMAGIC(sv)) {
2435 SV * tmpstr;
2436 if (flags & SV_SKIP_OVERLOAD)
2437 return 0;
2438 tmpstr = AMG_CALLunary(sv, numer_amg);
2439 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2440 return SvIV(tmpstr);
2441 }
2442 }
2443 return PTR2IV(SvRV(sv));
2444 }
2445
8d919b0a 2446 if (SvVALID(sv) || isREGEXP(sv)) {
4e8879f3
DM
2447 /* FBMs use the space for SvIVX and SvNVX for other purposes, so
2448 must not let them cache IVs.
2b2b6d6d
NC
2449 In practice they are extremely unlikely to actually get anywhere
2450 accessible by user Perl code - the only way that I'm aware of is when
2451 a constant subroutine which is used as the second argument to index.
cd84013a
FC
2452
2453 Regexps have no SvIVX and SvNVX fields.
2b2b6d6d 2454 */
df6b4bd5 2455 assert(SvPOKp(sv));
e20b6c3b 2456 {
71c558c3 2457 UV value;
8d919b0a
FC
2458 const char * const ptr =
2459 isREGEXP(sv) ? RX_WRAPPED((REGEXP*)sv) : SvPVX_const(sv);
e91de695
JH
2460 const int numtype
2461 = grok_number(ptr, SvCUR(sv), &value);
71c558c3
NC
2462
2463 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2464 == IS_NUMBER_IN_UV) {
2465 /* It's definitely an integer */
2466 if (numtype & IS_NUMBER_NEG) {
2467 if (value < (UV)IV_MIN)
2468 return -(IV)value;
2469 } else {
2470 if (value < (UV)IV_MAX)
2471 return (IV)value;
2472 }
2473 }
058b8ae2 2474
e91de695
JH
2475 /* Quite wrong but no good choices. */
2476 if ((numtype & IS_NUMBER_INFINITY)) {
2477 return (numtype & IS_NUMBER_NEG) ? IV_MIN : IV_MAX;
2478 } else if ((numtype & IS_NUMBER_NAN)) {
2479 return 0; /* So wrong. */
2480 }
2481
71c558c3
NC
2482 if (!numtype) {
2483 if (ckWARN(WARN_NUMERIC))
2484 not_a_number(sv);
2485 }
8d919b0a 2486 return I_V(Atof(ptr));
e20b6c3b 2487 }
4bac9ae4
CS
2488 }
2489
2490 if (SvTHINKFIRST(sv)) {
af359546
NC
2491 if (SvREADONLY(sv) && !SvOK(sv)) {
2492 if (ckWARN(WARN_UNINITIALIZED))
2493 report_uninit(sv);
2494 return 0;
2495 }
2496 }
4bac9ae4 2497
af359546
NC
2498 if (!SvIOKp(sv)) {
2499 if (S_sv_2iuv_common(aTHX_ sv))
2500 return 0;
79072805 2501 }
4bac9ae4 2502
147e3846 2503 DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2iv(%" IVdf ")\n",
1d7c1841 2504 PTR2UV(sv),SvIVX(sv)));
25da4f38 2505 return SvIsUV(sv) ? (IV)SvUVX(sv) : SvIVX(sv);
79072805
LW
2506}
2507
645c22ef 2508/*
891f9566 2509=for apidoc sv_2uv_flags
645c22ef
DM
2510
2511Return the unsigned integer value of an SV, doing any necessary string
c5608a1f 2512conversion. If C<flags> has the C<SV_GMAGIC> bit set, does an C<mg_get()> first.
891f9566 2513Normally used via the C<SvUV(sv)> and C<SvUVx(sv)> macros.
645c22ef 2514
58ae9391
KW
2515=for apidoc Amnh||SV_GMAGIC
2516
645c22ef
DM
2517=cut
2518*/
2519
ff68c719 2520UV
5aaab254 2521Perl_sv_2uv_flags(pTHX_ SV *const sv, const I32 flags)
ff68c719 2522{
1061065f 2523 PERL_ARGS_ASSERT_SV_2UV_FLAGS;
4bac9ae4
CS
2524
2525 if (SvGMAGICAL(sv) && (flags & SV_GMAGIC))
2526 mg_get(sv);
2527
2528 if (SvROK(sv)) {
2529 if (SvAMAGIC(sv)) {
2530 SV *tmpstr;
2531 if (flags & SV_SKIP_OVERLOAD)
2532 return 0;
2533 tmpstr = AMG_CALLunary(sv, numer_amg);
2534 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2535 return SvUV(tmpstr);
2536 }
2537 }
2538 return PTR2UV(SvRV(sv));
2539 }
2540
8d919b0a 2541 if (SvVALID(sv) || isREGEXP(sv)) {
2b2b6d6d 2542 /* FBMs use the space for SvIVX and SvNVX for other purposes, and use
cd84013a
FC
2543 the same flag bit as SVf_IVisUV, so must not let them cache IVs.
2544 Regexps have no SvIVX and SvNVX fields. */
df6b4bd5 2545 assert(SvPOKp(sv));
e20b6c3b 2546 {
71c558c3 2547 UV value;
8d919b0a
FC
2548 const char * const ptr =
2549 isREGEXP(sv) ? RX_WRAPPED((REGEXP*)sv) : SvPVX_const(sv);
e91de695
JH
2550 const int numtype
2551 = grok_number(ptr, SvCUR(sv), &value);
71c558c3
NC
2552
2553 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2554 == IS_NUMBER_IN_UV) {
2555 /* It's definitely an integer */
2556 if (!(numtype & IS_NUMBER_NEG))
2557 return value;
2558 }
058b8ae2 2559
e91de695
JH
2560 /* Quite wrong but no good choices. */
2561 if ((numtype & IS_NUMBER_INFINITY)) {
2562 return UV_MAX; /* So wrong. */
2563 } else if ((numtype & IS_NUMBER_NAN)) {
2564 return 0; /* So wrong. */
2565 }
2566
71c558c3
NC
2567 if (!numtype) {
2568 if (ckWARN(WARN_NUMERIC))
2569 not_a_number(sv);
2570 }
8d919b0a 2571 return U_V(Atof(ptr));
e20b6c3b 2572 }
4bac9ae4
CS
2573 }
2574
2575 if (SvTHINKFIRST(sv)) {
0336b60e 2576 if (SvREADONLY(sv) && !SvOK(sv)) {
0336b60e 2577 if (ckWARN(WARN_UNINITIALIZED))
29489e7c 2578 report_uninit(sv);
ff68c719
PP
2579 return 0;
2580 }
2581 }
4bac9ae4 2582
af359546
NC
2583 if (!SvIOKp(sv)) {
2584 if (S_sv_2iuv_common(aTHX_ sv))
2585 return 0;
ff68c719 2586 }
25da4f38 2587
147e3846 2588 DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2uv(%" UVuf ")\n",
1d7c1841 2589 PTR2UV(sv),SvUVX(sv)));
25da4f38 2590 return SvIsUV(sv) ? SvUVX(sv) : (UV)SvIVX(sv);
ff68c719
PP
2591}
2592
645c22ef 2593/*
196007d1 2594=for apidoc sv_2nv_flags
645c22ef
DM
2595
2596Return the num value of an SV, doing any necessary string or integer
c5608a1f 2597conversion. If C<flags> has the C<SV_GMAGIC> bit set, does an C<mg_get()> first.
39d5de13 2598Normally used via the C<SvNV(sv)> and C<SvNVx(sv)> macros.
645c22ef
DM
2599
2600=cut
2601*/
2602
65202027 2603NV
5aaab254 2604Perl_sv_2nv_flags(pTHX_ SV *const sv, const I32 flags)
79072805 2605{
1061065f
DD
2606 PERL_ARGS_ASSERT_SV_2NV_FLAGS;
2607
217f6fa3
FC
2608 assert (SvTYPE(sv) != SVt_PVAV && SvTYPE(sv) != SVt_PVHV
2609 && SvTYPE(sv) != SVt_PVFM);
8d919b0a 2610 if (SvGMAGICAL(sv) || SvVALID(sv) || isREGEXP(sv)) {
2b2b6d6d 2611 /* FBMs use the space for SvIVX and SvNVX for other purposes, and use
cd84013a
FC
2612 the same flag bit as SVf_IVisUV, so must not let them cache NVs.
2613 Regexps have no SvIVX and SvNVX fields. */
8d919b0a 2614 const char *ptr;
39d5de13
DM
2615 if (flags & SV_GMAGIC)
2616 mg_get(sv);
463ee0b2
LW
2617 if (SvNOKp(sv))
2618 return SvNVX(sv);
cd84013a 2619 if (SvPOKp(sv) && !SvIOKp(sv)) {
8d919b0a 2620 ptr = SvPVX_const(sv);
041457d9 2621 if (!SvIOKp(sv) && ckWARN(WARN_NUMERIC) &&
8d919b0a 2622 !grok_number(ptr, SvCUR(sv), NULL))
a0d0e21e 2623 not_a_number(sv);
8d919b0a 2624 return Atof(ptr);
a0d0e21e 2625 }
25da4f38 2626 if (SvIOKp(sv)) {
1c846c1f 2627 if (SvIsUV(sv))
65202027 2628 return (NV)SvUVX(sv);
25da4f38 2629 else
65202027 2630 return (NV)SvIVX(sv);
47a72cb8
NC
2631 }
2632 if (SvROK(sv)) {
2633 goto return_rok;
2634 }
2635 assert(SvTYPE(sv) >= SVt_PVMG);
2636 /* This falls through to the report_uninit near the end of the
2637 function. */
2638 } else if (SvTHINKFIRST(sv)) {
a0d0e21e 2639 if (SvROK(sv)) {
47a72cb8 2640 return_rok:
deb46114 2641 if (SvAMAGIC(sv)) {
aee036bb
DM
2642 SV *tmpstr;
2643 if (flags & SV_SKIP_OVERLOAD)
2644 return 0;
31d632c3 2645 tmpstr = AMG_CALLunary(sv, numer_amg);
deb46114
NC
2646 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2647 return SvNV(tmpstr);
2648 }
2649 }
2650 return PTR2NV(SvRV(sv));
a0d0e21e 2651 }
0336b60e 2652 if (SvREADONLY(sv) && !SvOK(sv)) {
599cee73 2653 if (ckWARN(WARN_UNINITIALIZED))
29489e7c 2654 report_uninit(sv);
ed6116ce
LW
2655 return 0.0;
2656 }
79072805
LW
2657 }
2658 if (SvTYPE(sv) < SVt_NV) {
7e25a7e9
NC
2659 /* The logic to use SVt_PVNV if necessary is in sv_upgrade. */
2660 sv_upgrade(sv, SVt_NV);
b2f82b52 2661 CLANG_DIAG_IGNORE_STMT(-Wthread-safety);
097ee67d 2662 DEBUG_c({
688523a0
KW
2663 DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
2664 STORE_LC_NUMERIC_SET_STANDARD();
1d7c1841 2665 PerlIO_printf(Perl_debug_log,
147e3846 2666 "0x%" UVxf " num(%" NVgf ")\n",
1d7c1841 2667 PTR2UV(sv), SvNVX(sv));
688523a0 2668 RESTORE_LC_NUMERIC();
097ee67d 2669 });
b2f82b52
KW
2670 CLANG_DIAG_RESTORE_STMT;
2671
79072805
LW
2672 }
2673 else if (SvTYPE(sv) < SVt_PVNV)
2674 sv_upgrade(sv, SVt_PVNV);
59d8ce62
NC
2675 if (SvNOKp(sv)) {
2676 return SvNVX(sv);
61604483 2677 }
59d8ce62 2678 if (SvIOKp(sv)) {
9d6ce603 2679 SvNV_set(sv, SvIsUV(sv) ? (NV)SvUVX(sv) : (NV)SvIVX(sv));
28e5dec8 2680#ifdef NV_PRESERVES_UV
a43d94f2
NC
2681 if (SvIOK(sv))
2682 SvNOK_on(sv);
2683 else
2684 SvNOKp_on(sv);
28e5dec8
JH
2685#else
2686 /* Only set the public NV OK flag if this NV preserves the IV */
2687 /* Check it's not 0xFFFFFFFFFFFFFFFF */
a43d94f2
NC
2688 if (SvIOK(sv) &&
2689 SvIsUV(sv) ? ((SvUVX(sv) != UV_MAX)&&(SvUVX(sv) == U_V(SvNVX(sv))))
28e5dec8
JH
2690 : (SvIVX(sv) == I_V(SvNVX(sv))))
2691 SvNOK_on(sv);
2692 else
2693 SvNOKp_on(sv);
2694#endif
93a17b20 2695 }
cd84013a 2696 else if (SvPOKp(sv)) {
c2988b20 2697 UV value;
3823048b 2698 const int numtype = grok_number(SvPVX_const(sv), SvCUR(sv), &value);
041457d9 2699 if (!SvIOKp(sv) && !numtype && ckWARN(WARN_NUMERIC))
a0d0e21e 2700 not_a_number(sv);
28e5dec8 2701#ifdef NV_PRESERVES_UV
c2988b20
NC
2702 if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2703 == IS_NUMBER_IN_UV) {
5e045b90 2704 /* It's definitely an integer */
9d6ce603 2705 SvNV_set(sv, (numtype & IS_NUMBER_NEG) ? -(NV)value : (NV)value);
66d83377 2706 } else {
3823048b 2707 S_sv_setnv(aTHX_ sv, numtype);
66d83377 2708 }
a43d94f2
NC
2709 if (numtype)
2710 SvNOK_on(sv);
2711 else
2712 SvNOKp_on(sv);
28e5dec8 2713#else
e91de695
JH
2714 SvNV_set(sv, Atof(SvPVX_const(sv)));
2715 /* Only set the public NV OK flag if this NV preserves the value in
2716 the PV at least as well as an IV/UV would.
2717 Not sure how to do this 100% reliably. */
2718 /* if that shift count is out of range then Configure's test is
2719 wonky. We shouldn't be in here with NV_PRESERVES_UV_BITS ==
2720 UV_BITS */
2721 if (((UV)1 << NV_PRESERVES_UV_BITS) >
2722 U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))) {
2723 SvNOK_on(sv); /* Definitely small enough to preserve all bits */
2724 } else if (!(numtype & IS_NUMBER_IN_UV)) {
2725 /* Can't use strtol etc to convert this string, so don't try.
2726 sv_2iv and sv_2uv will use the NV to convert, not the PV. */
c2988b20
NC
2727 SvNOK_on(sv);
2728 } else {
e91de695 2729 /* value has been set. It may not be precise. */
53e2bfb7 2730 if ((numtype & IS_NUMBER_NEG) && (value >= (UV)IV_MIN)) {
e91de695
JH
2731 /* 2s complement assumption for (UV)IV_MIN */
2732 SvNOK_on(sv); /* Integer is too negative. */
c2988b20 2733 } else {
e91de695
JH
2734 SvNOKp_on(sv);
2735 SvIOKp_on(sv);
6fa402ec 2736
e91de695 2737 if (numtype & IS_NUMBER_NEG) {
02b08bbc
DM
2738 /* -IV_MIN is undefined, but we should never reach
2739 * this point with both IS_NUMBER_NEG and value ==
2740 * (UV)IV_MIN */
2741 assert(value != (UV)IV_MIN);
e91de695
JH
2742 SvIV_set(sv, -(IV)value);
2743 } else if (value <= (UV)IV_MAX) {
2744 SvIV_set(sv, (IV)value);
2745 } else {
2746 SvUV_set(sv, value);
2747 SvIsUV_on(sv);
2748 }
c2988b20 2749
e91de695
JH
2750 if (numtype & IS_NUMBER_NOT_INT) {
2751 /* I believe that even if the original PV had decimals,
2752 they are lost beyond the limit of the FP precision.
2753 However, neither is canonical, so both only get p
2754 flags. NWC, 2000/11/25 */
2755 /* Both already have p flags, so do nothing */
2756 } else {
2757 const NV nv = SvNVX(sv);
2758 /* XXX should this spot have NAN_COMPARE_BROKEN, too? */
2759 if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
2760 if (SvIVX(sv) == I_V(nv)) {
2761 SvNOK_on(sv);
2762 } else {
2763 /* It had no "." so it must be integer. */
2764 }
2765 SvIOK_on(sv);
0f83c5a4 2766 } else {
e91de695
JH
2767 /* between IV_MAX and NV(UV_MAX).
2768 Could be slightly > UV_MAX */
2769
2770 if (numtype & IS_NUMBER_NOT_INT) {
2771 /* UV and NV both imprecise. */
0f83c5a4 2772 } else {
e91de695
JH
2773 const UV nv_as_uv = U_V(nv);
2774
2775 if (value == nv_as_uv && SvUVX(sv) != UV_MAX) {
2776 SvNOK_on(sv);
c2988b20 2777 }
e91de695 2778 SvIOK_on(sv);
c2988b20
NC
2779 }
2780 }
2781 }
2782 }
0f83c5a4 2783 }
e91de695
JH
2784 /* It might be more code efficient to go through the entire logic above
2785 and conditionally set with SvNOKp_on() rather than SvNOK(), but it
2786 gets complex and potentially buggy, so more programmer efficient
2787 to do it this way, by turning off the public flags: */
2788 if (!numtype)
2789 SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK);
28e5dec8 2790#endif /* NV_PRESERVES_UV */
93a17b20 2791 }
79072805 2792 else {
e91de695
JH
2793 if (isGV_with_GP(sv)) {
2794 glob_2number(MUTABLE_GV(sv));
2795 return 0.0;
2796 }
180488f8 2797
e91de695
JH
2798 if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
2799 report_uninit(sv);
2800 assert (SvTYPE(sv) >= SVt_NV);
2801 /* Typically the caller expects that sv_any is not NULL now. */
2802 /* XXX Ilya implies that this is a bug in callers that assume this
2803 and ideally should be fixed. */
2804 return 0.0;
79072805 2805 }
b2f82b52 2806 CLANG_DIAG_IGNORE_STMT(-Wthread-safety);
097ee67d 2807 DEBUG_c({
688523a0
KW
2808 DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
2809 STORE_LC_NUMERIC_SET_STANDARD();
147e3846 2810 PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2nv(%" NVgf ")\n",
e91de695 2811 PTR2UV(sv), SvNVX(sv));
688523a0 2812 RESTORE_LC_NUMERIC();
e91de695 2813 });
b2f82b52 2814 CLANG_DIAG_RESTORE_STMT;
463ee0b2 2815 return SvNVX(sv);
79072805
LW
2816}
2817
800401ee
JH
2818/*
2819=for apidoc sv_2num
2820
2821Return an SV with the numeric value of the source SV, doing any necessary
d024d1a7
FC
2822reference or overload conversion. The caller is expected to have handled
2823get-magic already.
800401ee
JH
2824
2825=cut
2826*/
2827
2828SV *
5aaab254 2829Perl_sv_2num(pTHX_ SV *const sv)
800401ee 2830{
7918f24d
NC
2831 PERL_ARGS_ASSERT_SV_2NUM;
2832
b9ee0594
RGS
2833 if (!SvROK(sv))
2834 return sv;
800401ee 2835 if (SvAMAGIC(sv)) {
31d632c3 2836 SV * const tmpsv = AMG_CALLunary(sv, numer_amg);
a02ec77a 2837 TAINT_IF(tmpsv && SvTAINTED(tmpsv));
800401ee
JH
2838 if (tmpsv && (!SvROK(tmpsv) || (SvRV(tmpsv) != SvRV(sv))))
2839 return sv_2num(tmpsv);
2840 }
2841 return sv_2mortal(newSVuv(PTR2UV(SvRV(sv))));
2842}
2843
dd0a5f5f
TK
2844/* int2str_table: lookup table containing string representations of all
2845 * two digit numbers. For example, int2str_table.arr[0] is "00" and
2846 * int2str_table.arr[12*2] is "12".
2847 *
2848 * We are going to read two bytes at a time, so we have to ensure that
2849 * the array is aligned to a 2 byte boundary. That's why it was made a
2850 * union with a dummy U16 member. */
2851static const union {
2852 char arr[200];
2853 U16 dummy;
2854} int2str_table = {{
2855 '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6',
2856 '0', '7', '0', '8', '0', '9', '1', '0', '1', '1', '1', '2', '1', '3',
2857 '1', '4', '1', '5', '1', '6', '1', '7', '1', '8', '1', '9', '2', '0',
2858 '2', '1', '2', '2', '2', '3', '2', '4', '2', '5', '2', '6', '2', '7',
2859 '2', '8', '2', '9', '3', '0', '3', '1', '3', '2', '3', '3', '3', '4',
2860 '3', '5', '3', '6', '3', '7', '3', '8', '3', '9', '4', '0', '4', '1',
2861 '4', '2', '4', '3', '4', '4', '4', '5', '4', '6', '4', '7', '4', '8',
2862 '4', '9', '5', '0', '5', '1', '5', '2', '5', '3', '5', '4', '5', '5',
2863 '5', '6', '5', '7', '5', '8', '5', '9', '6', '0', '6', '1', '6', '2',
2864 '6', '3', '6', '4', '6', '5', '6', '6', '6', '7', '6', '8', '6', '9',
2865 '7', '0', '7', '1', '7', '2', '7', '3', '7', '4', '7', '5', '7', '6',
2866 '7', '7', '7', '8', '7', '9', '8', '0', '8', '1', '8', '2', '8', '3',
2867 '8', '4', '8', '5', '8', '6', '8', '7', '8', '8', '8', '9', '9', '0',
2868 '9', '1', '9', '2', '9', '3', '9', '4', '9', '5', '9', '6', '9', '7',
2869 '9', '8', '9', '9'
2870}};
2871
645c22ef
DM
2872/* uiv_2buf(): private routine for use by sv_2pv_flags(): print an IV or
2873 * UV as a string towards the end of buf, and return pointers to start and
2874 * end of it.
2875 *
2876 * We assume that buf is at least TYPE_CHARS(UV) long.
2877 */
2878
dd0a5f5f 2879PERL_STATIC_INLINE char *
5de3775c 2880S_uiv_2buf(char *const buf, const IV iv, UV uv, const int is_uv, char **const peob)
25da4f38 2881{
25da4f38 2882 char *ptr = buf + TYPE_CHARS(UV);
823a54a3 2883 char * const ebuf = ptr;
25da4f38 2884 int sign;
dd0a5f5f 2885 U16 *word_ptr, *word_table;
25da4f38 2886
7918f24d
NC
2887 PERL_ARGS_ASSERT_UIV_2BUF;
2888
dd0a5f5f
TK
2889 /* ptr has to be properly aligned, because we will cast it to U16* */
2890 assert(PTR2nat(ptr) % 2 == 0);
2891 /* we are going to read/write two bytes at a time */
2892 word_ptr = (U16*)ptr;
2893 word_table = (U16*)int2str_table.arr;
2894
2895 if (UNLIKELY(is_uv))
25da4f38
IZ
2896 sign = 0;
2897 else if (iv >= 0) {
2898 uv = iv;
2899 sign = 0;
2900 } else {
7895b980
KW
2901 /* Using 0- here to silence bogus warning from MS VC */
2902 uv = (UV) (0 - (UV) iv);
25da4f38
IZ
2903 sign = 1;
2904 }
dd0a5f5f
TK
2905
2906 while (uv > 99) {
2907 *--word_ptr = word_table[uv % 100];
2908 uv /= 100;
2909 }
2910 ptr = (char*)word_ptr;
2911
2912 if (uv < 10)
2913 *--ptr = (char)uv + '0';
2914 else {
2915 *--word_ptr = word_table[uv];
2916 ptr = (char*)word_ptr;
2917 }
2918
25da4f38 2919 if (sign)
dd0a5f5f
TK
2920 *--ptr = '-';
2921
25da4f38
IZ
2922 *peob = ebuf;
2923 return ptr;
2924}
2925
bfaa02d5
JH
2926/* Helper for sv_2pv_flags and sv_vcatpvfn_flags. If the NV is an
2927 * infinity or a not-a-number, writes the appropriate strings to the
2928 * buffer, including a zero byte. On success returns the written length,
3bde2d43
JH
2929 * excluding the zero byte, on failure (not an infinity, not a nan)
2930 * returns zero, assert-fails on maxlen being too short.
3823048b
JH
2931 *
2932 * XXX for "Inf", "-Inf", and "NaN", we could have three read-only
2933 * shared string constants we point to, instead of generating a new
2934 * string for each instance. */
bfaa02d5 2935STATIC size_t
3823048b 2936S_infnan_2pv(NV nv, char* buffer, size_t maxlen, char plus) {
3bde2d43 2937 char* s = buffer;
bfaa02d5 2938 assert(maxlen >= 4);
3bde2d43
JH
2939 if (Perl_isinf(nv)) {
2940 if (nv < 0) {
2941 if (maxlen < 5) /* "-Inf\0" */
2942 return 0;
2943 *s++ = '-';
2944 } else if (plus) {
2945 *s++ = '+';
6e915616 2946 }
3bde2d43
JH
2947 *s++ = 'I';
2948 *s++ = 'n';
2949 *s++ = 'f';
2950 }
2951 else if (Perl_isnan(nv)) {
2952 *s++ = 'N';
2953 *s++ = 'a';
2954 *s++ = 'N';
2955 /* XXX optionally output the payload mantissa bits as
2956 * "(unsigned)" (to match the nan("...") C99 function,
2957 * or maybe as "(0xhhh...)" would make more sense...
2958 * provide a format string so that the user can decide?
2959 * NOTE: would affect the maxlen and assert() logic.*/
2960 }
2961 else {
2962 return 0;
bfaa02d5 2963 }
3bde2d43 2964 assert((s == buffer + 3) || (s == buffer + 4));
defe49c8
AL
2965 *s = 0;
2966 return s - buffer;
bfaa02d5
JH
2967}
2968
2969/*
2970=for apidoc sv_2pv_flags
2971
796b6530 2972Returns a pointer to the string value of an SV, and sets C<*lp> to its length.
c5608a1f 2973If flags has the C<SV_GMAGIC> bit set, does an C<mg_get()> first. Coerces C<sv> to a
bfaa02d5
JH
2974string if necessary. Normally invoked via the C<SvPV_flags> macro.
2975C<sv_2pv()> and C<sv_2pv_nomg> usually end up here too.
2976
2977=cut
2978*/
2979
2980char *
2981Perl_sv_2pv_flags(pTHX_ SV *const sv, STRLEN *const lp, const I32 flags)
2982{
2983 char *s;
2984
2985 PERL_ARGS_ASSERT_SV_2PV_FLAGS;
2986
2987 assert (SvTYPE(sv) != SVt_PVAV && SvTYPE(sv) != SVt_PVHV
2988 && SvTYPE(sv) != SVt_PVFM);
2989 if (SvGMAGICAL(sv) && (flags & SV_GMAGIC))
2990 mg_get(sv);
2991 if (SvROK(sv)) {
2992 if (SvAMAGIC(sv)) {
2993 SV *tmpstr;
2994 if (flags & SV_SKIP_OVERLOAD)
2995 return NULL;
2996 tmpstr = AMG_CALLunary(sv, string_amg);
2997 TAINT_IF(tmpstr && SvTAINTED(tmpstr));
2998 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2999 /* Unwrap this: */
3000 /* char *pv = lp ? SvPV(tmpstr, *lp) : SvPV_nolen(tmpstr);
3001 */
3002
3003 char *pv;
3004 if ((SvFLAGS(tmpstr) & (SVf_POK)) == SVf_POK) {
3005 if (flags & SV_CONST_RETURN) {
3006 pv = (char *) SvPVX_const(tmpstr);
3007 } else {
3008 pv = (flags & SV_MUTABLE_RETURN)
3009 ? SvPVX_mutable(tmpstr) : SvPVX(tmpstr);
3010 }
3011 if (lp)
3012 *lp = SvCUR(tmpstr);
3013 } else {
3014 pv = sv_2pv_flags(tmpstr, lp, flags);
3015 }
3016 if (SvUTF8(tmpstr))
3017 SvUTF8_on(sv);
3018 else
3019 SvUTF8_off(sv);
3020 return pv;
3021 }
3022 }
3023 {
3024 STRLEN len;
3025 char *retval;
3026 char *buffer;
3027 SV *const referent = SvRV(sv);
3028
3029 if (!referent) {
3030 len = 7;
3031 retval = buffer = savepvn("NULLREF", len);
3032 } else if (SvTYPE(referent) == SVt_REGEXP &&
3033 (!(PL_curcop->cop_hints & HINT_NO_AMAGIC) ||
3034 amagic_is_enabled(string_amg))) {
3035 REGEXP * const re = (REGEXP *)MUTABLE_PTR(referent);
3036
3037 assert(re);
3038
3039 /* If the regex is UTF-8 we want the containing scalar to
3040 have an UTF-8 flag too */
3041 if (RX_UTF8(re))
3042 SvUTF8_on(sv);
3043 else
3044 SvUTF8_off(sv);
3045
3046 if (lp)
3047 *lp = RX_WRAPLEN(re);
3048
3049 return RX_WRAPPED(re);
3050 } else {
3051 const char *const typestr = sv_reftype(referent, 0);
3052 const STRLEN typelen = strlen(typestr);
3053 UV addr = PTR2UV(referent);
3054 const char *stashname = NULL;
3055 STRLEN stashnamelen = 0; /* hush, gcc */
3056 const char *buffer_end;
3057
3058 if (SvOBJECT(referent)) {
3059 const HEK *const name = HvNAME_HEK(SvSTASH(referent));
3060
3061 if (name) {
3062 stashname = HEK_KEY(name);
3063 stashnamelen = HEK_LEN(name);
3064
3065 if (HEK_UTF8(name)) {
3066 SvUTF8_on(sv);
3067 } else {
3068 SvUTF8_off(sv);
3069 }
3070 } else {
3071 stashname = "__ANON__";
3072 stashnamelen = 8;
3073 }
3074 len = stashnamelen + 1 /* = */ + typelen + 3 /* (0x */
3075 + 2 * sizeof(UV) + 2 /* )\0 */;
3076 } else {
3077 len = typelen + 3 /* (0x */
3078 + 2 * sizeof(UV) + 2 /* )\0 */;
3079 }
fafee734 3080
4bac9ae4
CS
3081 Newx(buffer, len, char);
3082 buffer_end = retval = buffer + len;
3083
3084 /* Working backwards */
3085 *--retval = '\0';
3086 *--retval = ')';
3087 do {
3088 *--retval = PL_hexdigit[addr & 15];
3089 } while (addr >>= 4);
3090 *--retval = 'x';
3091 *--retval = '0';
3092 *--retval = '(';
3093
3094 retval -= typelen;
3095 memcpy(retval, typestr, typelen);
3096
3097 if (stashname) {
3098 *--retval = '=';
3099 retval -= stashnamelen;
3100 memcpy(retval, stashname, stashnamelen);
c080367d 3101 }
4bac9ae4
CS
3102 /* retval may not necessarily have reached the start of the
3103 buffer here. */
3104 assert (retval >= buffer);
3105
3106 len = buffer_end - retval - 1; /* -1 for that \0 */
463ee0b2 3107 }
cdb061a3 3108 if (lp)
4bac9ae4
CS
3109 *lp = len;
3110 SAVEFREEPV(buffer);
3111 return retval;
79072805 3112 }
79072805 3113 }
4bac9ae4
CS
3114
3115 if (SvPOKp(sv)) {
3116 if (lp)
3117 *lp = SvCUR(sv);
3118 if (flags & SV_MUTABLE_RETURN)
3119 return SvPVX_mutable(sv);
3120 if (flags & SV_CONST_RETURN)
3121 return (char *)SvPVX_const(sv);
3122 return SvPVX(sv);
3123 }
3124
3125 if (SvIOK(sv)) {
28e5dec8
JH
3126 /* I'm assuming that if both IV and NV are equally valid then
3127 converting the IV is going to be more efficient */
e1ec3a88 3128 const U32 isUIOK = SvIsUV(sv);
dd0a5f5f
TK
3129 /* The purpose of this union is to ensure that arr is aligned on
3130 a 2 byte boundary, because that is what uiv_2buf() requires */
3131 union {
3132 char arr[TYPE_CHARS(UV)];
3133 U16 dummy;
3134 } buf;
28e5dec8 3135 char *ebuf, *ptr;
97a130b8 3136 STRLEN len;
28e5dec8
JH
3137
3138 if (SvTYPE(sv) < SVt_PVIV)
3139 sv_upgrade(sv, SVt_PVIV);
dd0a5f5f 3140 ptr = uiv_2buf(buf.arr, SvIVX(sv), SvUVX(sv), isUIOK, &ebuf);
97a130b8 3141 len = ebuf - ptr;
5902b6a9 3142 /* inlined from sv_setpvn */
97a130b8
NC
3143 s = SvGROW_mutable(sv, len + 1);
3144 Move(ptr, s, len, char);
3145 s += len;
28e5dec8 3146 *s = '\0';
b127e37e 3147 SvPOK_on(sv);
28e5dec8 3148 }
4bac9ae4 3149 else if (SvNOK(sv)) {
79072805
LW
3150 if (SvTYPE(sv) < SVt_PVNV)
3151 sv_upgrade(sv, SVt_PVNV);
128eeacb
DD
3152 if (SvNVX(sv) == 0.0
3153#if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
3154 && !Perl_isnan(SvNVX(sv))
3155#endif
3156 ) {
29912d93
NC
3157 s = SvGROW_mutable(sv, 2);
3158 *s++ = '0';
3159 *s = '\0';
3160 } else {
5e85836e 3161 STRLEN len;
fb8cdbc5 3162 STRLEN size = 5; /* "-Inf\0" */
0c7e610f 3163
fb8cdbc5 3164 s = SvGROW_mutable(sv, size);
3823048b 3165 len = S_infnan_2pv(SvNVX(sv), s, size, 0);
fb8cdbc5 3166 if (len > 0) {
0c7e610f 3167 s += len;
fb8cdbc5
JH
3168 SvPOK_on(sv);
3169 }
0c7e610f 3170 else {
0c7e610f 3171 /* some Xenix systems wipe out errno here */
fb8cdbc5
JH
3172 dSAVE_ERRNO;
3173
3840bff0
JH
3174 size =
3175 1 + /* sign */
3176 1 + /* "." */
3177 NV_DIG +
3178 1 + /* "e" */
3179 1 + /* sign */
3180 5 + /* exponent digits */
3181 1 + /* \0 */
3182 2; /* paranoia */
b127e37e 3183
fb8cdbc5 3184 s = SvGROW_mutable(sv, size);
b127e37e 3185#ifndef USE_LOCALE_NUMERIC
a4eca1d4
JH
3186 SNPRINTF_G(SvNVX(sv), s, SvLEN(sv), NV_DIG);
3187
0c7e610f
JH
3188 SvPOK_on(sv);
3189#else
28acfe03 3190 {
3840bff0 3191 bool local_radix;
67d796ae
KW
3192 DECLARATION_FOR_LC_NUMERIC_MANIPULATION;
3193 STORE_LC_NUMERIC_SET_TO_NEEDED();
3840bff0 3194
dd2dbc5f 3195 local_radix = _NOT_IN_NUMERIC_STANDARD;
4c039fd8
DM
3196 if (local_radix && SvCUR(PL_numeric_radix_sv) > 1) {
3197 size += SvCUR(PL_numeric_radix_sv) - 1;
3840bff0
JH
3198 s = SvGROW_mutable(sv, size);
3199 }
3200
a4eca1d4 3201 SNPRINTF_G(SvNVX(sv), s, SvLEN(sv), NV_DIG);
0c7e610f
JH
3202
3203 /* If the radix character is UTF-8, and actually is in the
3204 * output, turn on the UTF-8 flag for the scalar */
3dbc6af5
KW
3205 if ( local_radix
3206 && SvUTF8(PL_numeric_radix_sv)
3207 && instr(s, SvPVX_const(PL_numeric_radix_sv)))
3208 {
3840bff0
JH
3209 SvUTF8_on(sv);
3210 }
3211
0c7e610f 3212 RESTORE_LC_NUMERIC();
28acfe03 3213 }
68e8f474 3214
0c7e610f
JH
3215 /* We don't call SvPOK_on(), because it may come to
3216 * pass that the locale changes so that the
3217 * stringification we just did is no longer correct. We
3218 * will have to re-stringify every time it is needed */
b127e37e 3219#endif
0c7e610f
JH
3220 RESTORE_ERRNO;
3221 }
3222 while (*s) s++;
bbce6d69 3223 }
79072805 3224 }
4bac9ae4
CS
3225 else if (isGV_with_GP(sv)) {
3226 GV *const gv = MUTABLE_GV(sv);
3227 SV *const buffer = sv_newmortal();
8d1c3e26 3228
4bac9ae4 3229 gv_efullname3(buffer, gv, "*");
180488f8 3230
4bac9ae4
CS
3231 assert(SvPOK(buffer));
3232 if (SvUTF8(buffer))
3233 SvUTF8_on(sv);
1097da16
TC
3234 else
3235 SvUTF8_off(sv);
4bac9ae4
CS
3236 if (lp)
3237 *lp = SvCUR(buffer);
3238 return SvPVX(buffer);
3239 }
3240 else {
cdb061a3 3241 if (lp)
00b6aa41 3242 *lp = 0;
9f621bb0
NC
3243 if (flags & SV_UNDEF_RETURNS_NULL)
3244 return NULL;
4f62cd62 3245 if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
9f621bb0 3246 report_uninit(sv);
4bac9ae4
CS
3247 /* Typically the caller expects that sv_any is not NULL now. */
3248 if (!SvREADONLY(sv) && SvTYPE(sv) < SVt_PV)
25da4f38 3249 sv_upgrade(sv, SVt_PV);
73d840c0 3250 return (char *)"";
79072805 3251 }
4bac9ae4 3252
cdb061a3 3253 {
823a54a3 3254 const STRLEN len = s - SvPVX_const(sv);
cdb061a3
NC
3255 if (lp)
3256 *lp = len;
3257 SvCUR_set(sv, len);
3258 }
147e3846 3259 DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%" UVxf " 2pv(%s)\n",
3f7c398e 3260 PTR2UV(sv),SvPVX_const(sv)));
4d84ee25
NC
3261 if (flags & SV_CONST_RETURN)
3262 return (char *)SvPVX_const(sv);
10516c54
NC
3263 if (flags & SV_MUTABLE_RETURN)
3264 return SvPVX_mutable(sv);
463ee0b2
LW
3265 return SvPVX(sv);
3266}
3267
645c22ef 3268/*
6050d10e
JP
3269=for apidoc sv_copypv
3270
3271Copies a stringified representation of the source SV into the
796b6530 3272destination SV. Automatically performs any necessary C<mg_get> and
54f0641b 3273coercion of numeric values into strings. Guaranteed to preserve
796b6530
KW
3274C<UTF8> flag even from overloaded objects. Similar in nature to
3275C<sv_2pv[_flags]> but operates directly on an SV instead of just the
3276string. Mostly uses C<sv_2pv_flags> to do its work, except when that
6050d10e
JP
3277would lose the UTF-8'ness of the PV.
3278
4bac9ae4
CS
3279=for apidoc sv_copypv_nomg
3280
796b6530 3281Like C<sv_copypv>, but doesn't invoke get magic first.
4bac9ae4
CS
3282
3283=for apidoc sv_copypv_flags
3284
796b6530 3285Implementation of C<sv_copypv> and C<sv_copypv_nomg>. Calls get magic iff flags
c5608a1f 3286has the C<SV_GMAGIC> bit set.
4bac9ae4 3287
6050d10e
JP
3288=cut
3289*/
3290
3291void
5aaab254 3292Perl_sv_copypv_flags(pTHX_ SV *const dsv, SV *const ssv, const I32 flags)
4bac9ae4 3293{
446eaa42 3294 STRLEN len;
4bac9ae4 3295 const char *s;
7918f24d 3296
4bac9ae4 3297 PERL_ARGS_ASSERT_SV_COPYPV_FLAGS;
7918f24d 3298
c77ed9ca 3299 s = SvPV_flags_const(ssv,len,(flags & SV_GMAGIC));
cb50f42d 3300 sv_setpvn(dsv,s,len);
446eaa42 3301 if (SvUTF8(ssv))
cb50f42d 3302 SvUTF8_on(dsv);
446eaa42 3303 else
cb50f42d 3304 SvUTF8_off(dsv);
6050d10e
JP
3305}
3306
3307/*
645c22ef
DM
3308=for apidoc sv_2pvbyte
3309
796b6530 3310Return a pointer to the byte-encoded representation of the SV, and set C<*lp>
1e54db1a 3311to its length. May cause the SV to be downgraded from UTF-8 as a
645c22ef
DM
3312side-effect.
3313
3314Usually accessed via the C<SvPVbyte> macro.
3315
3316=cut
3317*/
3318
7340a771 3319char *
757fc329 3320Perl_sv_2pvbyte_flags(pTHX_ SV *sv, STRLEN *const lp, const U32 flags)
7340a771 3321{
757fc329 3322 PERL_ARGS_ASSERT_SV_2PVBYTE_FLAGS;
7918f24d 3323
757fc329
P
3324 if (SvGMAGICAL(sv) && (flags & SV_GMAGIC))
3325 mg_get(sv);
4499db73
FC
3326 if (((SvREADONLY(sv) || SvFAKE(sv)) && !SvIsCOW(sv))
3327 || isGV_with_GP(sv) || SvROK(sv)) {
a901b181 3328 SV *sv2 = sv_newmortal();
48120f8f 3329 sv_copypv_nomg(sv2,sv);
a901b181
FC
3330 sv = sv2;
3331 }
757fc329 3332 sv_utf8_downgrade_nomg(sv,0);
71eb6d8c 3333 return lp ? SvPV_nomg(sv,*lp) : SvPV_nomg_nolen(sv);
7340a771
GS
3334}
3335
645c22ef 3336/*
035cbb0e
RGS
3337=for apidoc sv_2pvutf8
3338
796b6530 3339Return a pointer to the UTF-8-encoded representation of the SV, and set C<*lp>
035cbb0e
RGS
3340to its length. May cause the SV to be upgraded to UTF-8 as a side-effect.
3341
3342Usually accessed via the C<SvPVutf8> macro.
3343
3344=cut
3345*/
645c22ef 3346
7340a771 3347char *
757fc329 3348Perl_sv_2pvutf8_flags(pTHX_ SV *sv, STRLEN *const lp, const U32 flags)
7340a771 3349{
757fc329 3350 PERL_ARGS_ASSERT_SV_2PVUTF8_FLAGS;
7918f24d 3351
757fc329
P
3352 if (SvGMAGICAL(sv) && (flags & SV_GMAGIC))
3353 mg_get(sv);
4499db73 3354 if (((SvREADONLY(sv) || SvFAKE(sv)) && !SvIsCOW(sv))
757fc329
P
3355 || isGV_with_GP(sv) || SvROK(sv)) {
3356 SV *sv2 = sv_newmortal();
3357 sv_copypv_nomg(sv2,sv);
3358 sv = sv2;
3359 }
4bac9ae4 3360 sv_utf8_upgrade_nomg(sv);
c3ec315f 3361 return lp ? SvPV_nomg(sv,*lp) : SvPV_nomg_nolen(sv);
7340a771 3362}
1c846c1f 3363
7ee2227d 3364
645c22ef
DM
3365/*
3366=for apidoc sv_2bool
3367
796b6530
KW
3368This macro is only used by C<sv_true()> or its macro equivalent, and only if
3369the latter's argument is neither C<SvPOK>, C<SvIOK> nor C<SvNOK>.
3370It calls C<sv_2bool_flags> with the C<SV_GMAGIC> flag.
06c841cf
FC
3371
3372=for apidoc sv_2bool_flags
3373
796b6530
KW
3374This function is only used by C<sv_true()> and friends, and only if
3375the latter's argument is neither C<SvPOK>, C<SvIOK> nor C<SvNOK>. If the flags
3376contain C<SV_GMAGIC>, then it does an C<mg_get()> first.
06c841cf 3377
645c22ef
DM
3378
3379=cut
3380*/
3381
463ee0b2 3382bool
9d176cd8 3383Perl_sv_2bool_flags(pTHX_ SV *sv, I32 flags)
463ee0b2 3384{
06c841cf 3385 PERL_ARGS_ASSERT_SV_2BOOL_FLAGS;
7918f24d 3386
9d176cd8 3387 restart:
06c841cf 3388 if(flags & SV_GMAGIC) SvGETMAGIC(sv);
463ee0b2 3389
a0d0e21e
LW
3390 if (!SvOK(sv))
3391 return 0;
3392 if (SvROK(sv)) {
fabdb6c0 3393 if (SvAMAGIC(sv)) {
31d632c3 3394 SV * const tmpsv = AMG_CALLunary(sv, bool__amg);
9d176cd8
DD
3395 if (tmpsv && (!SvROK(tmpsv) || (SvRV(tmpsv) != SvRV(sv)))) {
3396 bool svb;
3397 sv = tmpsv;
3398 if(SvGMAGICAL(sv)) {
3399 flags = SV_GMAGIC;
3400 goto restart; /* call sv_2bool */
3401 }
3402 /* expanded SvTRUE_common(sv, (flags = 0, goto restart)) */
3403 else if(!SvOK(sv)) {
3404 svb = 0;
3405 }
3406 else if(SvPOK(sv)) {
3407 svb = SvPVXtrue(sv);
3408 }
3409 else if((SvFLAGS(sv) & (SVf_IOK|SVf_NOK))) {
3410 svb = (SvIOK(sv) && SvIVX(sv) != 0)
659c4b96 3411 || (SvNOK(sv) && SvNVX(sv) != 0.0);
9d176cd8
DD
3412 }
3413 else {
3414 flags = 0;
3415 goto restart; /* call sv_2bool_nomg */
3416 }
3417 return cBOOL(svb);
3418 }
fabdb6c0 3419 }
e8f01ee5
DM
3420 assert(SvRV(sv));
3421 return TRUE;
a0d0e21e 3422 }
85b7d9b3
FC
3423 if (isREGEXP(sv))
3424 return
3425 RX_WRAPLEN(sv) > 1 || (RX_WRAPLEN(sv) && *RX_WRAPPED(sv) != '0');
1a436fbe
DM
3426
3427 if (SvNOK(sv) && !SvPOK(sv))
3428 return SvNVX(sv) != 0.0;
3429
4bac9ae4 3430 return SvTRUE_common(sv, isGV_with_GP(sv) ? 1 : 0);
79072805
LW
3431}
3432
c461cf8f
JH
3433/*
3434=for apidoc sv_utf8_upgrade
3435
78ea37eb 3436Converts the PV of an SV to its UTF-8-encoded form.
645c22ef 3437Forces the SV to string form if it is not already.
2bbc8d55 3438Will C<mg_get> on C<sv> if appropriate.
796b6530 3439Always sets the C<SvUTF8> flag to avoid future validity checks even
2bbc8d55
SP
3440if the whole string is the same in UTF-8 as not.
3441Returns the number of bytes in the converted string
c461cf8f 3442
0efd0472 3443This is not a general purpose byte encoding to Unicode interface:
13a6c0e0
JH
3444use the Encode extension for that.
3445
fe749c9a
KW
3446=for apidoc sv_utf8_upgrade_nomg
3447
796b6530 3448Like C<sv_utf8_upgrade>, but doesn't do magic on C<sv>.
fe749c9a 3449
8d6d96c1
HS
3450=for apidoc sv_utf8_upgrade_flags
3451
78ea37eb 3452Converts the PV of an SV to its UTF-8-encoded form.
645c22ef 3453Forces the SV to string form if it is not already.
8d6d96c1 3454Always sets the SvUTF8 flag to avoid future validity checks even
960b0271
FC
3455if all the bytes are invariant in UTF-8.
3456If C<flags> has C<SV_GMAGIC> bit set,
2bbc8d55 3457will C<mg_get> on C<sv> if appropriate, else not.
2a590426 3458
c58971e9 3459The C<SV_FORCE_UTF8_UPGRADE> flag is now ignored.
2a590426
KW
3460
3461Returns the number of bytes in the converted string.
8d6d96c1 3462
0efd0472 3463This is not a general purpose byte encoding to Unicode interface:
13a6c0e0
JH
3464use the Encode extension for that.
3465
2a590426 3466=for apidoc sv_utf8_upgrade_flags_grow
b3ab6785 3467
796b6530
KW
3468Like C<sv_utf8_upgrade_flags>, but has an additional parameter C<extra>, which is
3469the number of unused bytes the string of C<sv> is guaranteed to have free after
2a590426
KW
3470it upon return. This allows the caller to reserve extra space that it intends
3471to fill, to avoid extra grows.
b3ab6785 3472
2a590426
KW
3473C<sv_utf8_upgrade>, C<sv_utf8_upgrade_nomg>, and C<sv_utf8_upgrade_flags>
3474are implemented in terms of this function.
3475
3476Returns the number of bytes in the converted string (not including the spares).
3477
3478=cut
b3ab6785 3479
6602b933
KW
3480If the routine itself changes the string, it adds a trailing C<NUL>. Such a
3481C<NUL> isn't guaranteed due to having other routines do the work in some input
3482cases, or if the input is already flagged as being in utf8.
b3ab6785 3483
8d6d96c1
HS
3484*/
3485
3486STRLEN
5aaab254 3487Perl_sv_utf8_upgrade_flags_grow(pTHX_ SV *const sv, const I32 flags, STRLEN extra)
8d6d96c1 3488{
b3ab6785 3489 PERL_ARGS_ASSERT_SV_UTF8_UPGRADE_FLAGS_GROW;
7918f24d 3490
808c356f
RGS
3491 if (sv == &PL_sv_undef)
3492 return 0;
892f9127 3493 if (!SvPOK_nog(sv)) {
e0e62c2a 3494 STRLEN len = 0;
d52b7888
NC
3495 if (SvREADONLY(sv) && (SvPOKp(sv) || SvIOKp(sv) || SvNOKp(sv))) {
3496 (void) sv_2pv_flags(sv,&len, flags);
b3ab6785
KW
3497 if (SvUTF8(sv)) {
3498 if (extra) SvGROW(sv, SvCUR(sv) + extra);
d52b7888 3499 return len;
b3ab6785 3500 }
d52b7888 3501 } else {
33fb6f35 3502 (void) SvPV_force_flags(sv,len,flags & SV_GMAGIC);
d52b7888 3503 }
e0e62c2a 3504 }
4411f3b6 3505
fde84d2e
DM
3506 /* SVt_REGEXP's shouldn't be upgraded to UTF8 - they're already
3507 * compiled and individual nodes will remain non-utf8 even if the
3508 * stringified version of the pattern gets upgraded. Whether the
3509 * PVX of a REGEXP should be grown or we should just croak, I don't
3510 * know - DAPM */
3511 if (SvUTF8(sv) || isREGEXP(sv)) {
b3ab6785 3512 if (extra) SvGROW(sv, SvCUR(sv) + extra);
5fec3b1d 3513 return SvCUR(sv);
f5cee72b 3514 }
5fec3b1d 3515
765f542d 3516 if (SvIsCOW(sv)) {
c56ed9f6 3517 S_sv_uncow(aTHX_ sv, 0);
db42d148
NIS
3518 }
3519
4e93345f 3520 if (SvCUR(sv) == 0) {
e2e3bb6a
KW
3521 if (extra) SvGROW(sv, extra + 1); /* Make sure is room for a trailing
3522 byte */
4e93345f 3523 } else { /* Assume Latin-1/EBCDIC */
c4e7c712 3524 /* This function could be much more efficient if we
2bbc8d55 3525 * had a FLAG in SVs to signal if there are any variant
c4e7c712 3526 * chars in the PV. Given that there isn't such a flag
c58971e9 3527 * make the loop as fast as possible. */
b3ab6785 3528 U8 * s = (U8 *) SvPVX_const(sv);
b3ab6785 3529 U8 *t = s;
c4e7c712 3530
c58971e9 3531 if (is_utf8_invariant_string_loc(s, SvCUR(sv), (const U8 **) &t)) {
b3ab6785 3532
c58971e9
KW
3533 /* utf8 conversion not needed because all are invariants. Mark
3534 * as UTF-8 even if no variant - saves scanning loop */
3535 SvUTF8_on(sv);
3536 if (extra) SvGROW(sv, SvCUR(sv) + extra);
3537 return SvCUR(sv);
dc772057 3538 }
b3ab6785 3539
c58971e9
KW
3540 /* Here, there is at least one variant (t points to the first one), so
3541 * the string should be converted to utf8. Everything from 's' to
3542 * 't - 1' will occupy only 1 byte each on output.
dc772057 3543 *
c58971e9
KW
3544 * Note that the incoming SV may not have a trailing '\0', as certain
3545 * code in pp_formline can send us partially built SVs.
b3ab6785
KW
3546 *
3547 * There are two main ways to convert. One is to create a new string
3548 * and go through the input starting from the beginning, appending each
c58971e9
KW
3549 * converted value onto the new string as we go along. Going this
3550 * route, it's probably best to initially allocate enough space in the
3551 * string rather than possibly running out of space and having to
3552 * reallocate and then copy what we've done so far. Since everything
3553 * from 's' to 't - 1' is invariant, the destination can be initialized
3554 * with these using a fast memory copy. To be sure to allocate enough
3555 * space, one could use the worst case scenario, where every remaining
3556 * byte expands to two under UTF-8, or one could parse it and count
3557 * exactly how many do expand.
b3ab6785 3558 *
c58971e9
KW
3559 * The other way is to unconditionally parse the remainder of the
3560 * string to figure out exactly how big the expanded string will be,
3561 * growing if needed. Then start at the end of the string and place
3562 * the character there at the end of the unfilled space in the expanded
3563 * one, working backwards until reaching 't'.
b3ab6785 3564 *
c58971e9
KW
3565 * The problem with assuming the worst case scenario is that for very
3566 * long strings, we could allocate much more memory than actually
3567 * needed, which can create performance problems. If we have to parse
3568 * anyway, the second method is the winner as it may avoid an extra
3569 * copy. The code used to use the first method under some
3570 * circumstances, but now that there is faster variant counting on
3571 * ASCII platforms, the second method is used exclusively, eliminating
3572 * some code that no longer has to be maintained. */
b3ab6785
KW