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a0d0e21e 1/* hv.h
79072805 2 *
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3 * Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999,
4 * 2000, 2001, 2002, by Larry Wall and others
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5 *
6 * You may distribute under the terms of either the GNU General Public
7 * License or the Artistic License, as specified in the README file.
8 *
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9 */
10
5cbe4eec 11/* typedefs to eliminate some typing */
79072805 12typedef struct he HE;
ff68c719 13typedef struct hek HEK;
79072805 14
5cbe4eec 15/* entry in hash value chain */
79072805 16struct he {
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17 HE *hent_next; /* next entry in chain */
18 HEK *hent_hek; /* hash key */
19 SV *hent_val; /* scalar value that was hashed */
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20};
21
5cbe4eec 22/* hash key -- defined separately for use as shared pointer */
ff68c719 23struct hek {
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24 U32 hek_hash; /* hash of key */
25 I32 hek_len; /* length of hash key */
26 char hek_key[1]; /* variable-length hash key */
e05949c7 27 /* the hash-key is \0-terminated */
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28 /* after the \0 there is a byte for flags, such as whether the key
29 is UTF-8 */
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30};
31
5cbe4eec 32/* hash structure: */
6ee623d5 33/* This structure must match the beginning of struct xpvmg in sv.h. */
79072805 34struct xpvhv {
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35 char * xhv_array; /* pointer to malloced string */
36 STRLEN xhv_fill; /* how full xhv_array currently is */
37 STRLEN xhv_max; /* subscript of last element of xhv_array */
6ee623d5 38 IV xhv_keys; /* how many elements in the array */
65202027 39 NV xnv_nv; /* numeric value, if any */
8aacddc1 40#define xhv_placeholders xnv_nv
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41 MAGIC* xmg_magic; /* magic for scalar array */
42 HV* xmg_stash; /* class package */
43
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44 I32 xhv_riter; /* current root of iterator */
45 HE *xhv_eiter; /* current entry of iterator */
46 PMOP *xhv_pmroot; /* list of pm's for this package */
47 char *xhv_name; /* name, if a symbol table */
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48};
49
5cbe4eec 50/* hash a key */
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51/* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins
52 * from requirements by Colin Plumb.
53 * (http://burtleburtle.net/bob/hash/doobs.html) */
54/* The use of a temporary pointer and the casting games
55 * is needed to serve the dual purposes of
56 * (a) the hashed data being interpreted as "unsigned char" (new since 5.8,
57 * a "char" can be either signed or signed, depending on the compiler)
58 * (b) catering for old code that uses a "char"
830b38bd 59 *
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60 * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
61 * to avoid "algorithmic complexity attacks".
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62 *
63 * If USE_HASH_SEED is defined, hash randomisation is done by default
64 * If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done
65 * only if the environment variable PERL_HASH_SEED is set.
66 * For maximal control, one can define PERL_HASH_SEED.
67 * (see also erl.c:perl_parse()).
5afd6d42 68 */
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69#ifndef PERL_HASH_SEED
70# if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT)
71# define PERL_HASH_SEED PL_hash_seed
72# else
73# define PERL_HASH_SEED 0
74# endif
504f80c1 75#endif
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76#define PERL_HASH(hash,str,len) \
77 STMT_START { \
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78 register const char *s_PeRlHaSh_tmp = str; \
79 register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \
bf6bd887 80 register I32 i_PeRlHaSh = len; \
504f80c1 81 register U32 hash_PeRlHaSh = PERL_HASH_SEED; \
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82 while (i_PeRlHaSh--) { \
83 hash_PeRlHaSh += *s_PeRlHaSh++; \
84 hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
85 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
86 } \
87 hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
88 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
4fee5c71 89 (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
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90 } STMT_END
91
22718ec5 92#if defined (PERL_IN_HV_C) || defined (MOD_PERL)
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93#define PERL_HASH_INTERNAL(hash,str,len) \
94 STMT_START { \
95 register const char *s_PeRlHaSh_tmp = str; \
96 register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \
97 register I32 i_PeRlHaSh = len; \
008fb0c0 98 register U32 hash_PeRlHaSh = PL_rehash_seed; \
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99 while (i_PeRlHaSh--) { \
100 hash_PeRlHaSh += *s_PeRlHaSh++; \
101 hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
102 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
103 } \
104 hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
105 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
106 (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
107 } STMT_END
108#endif
109
954c1994 110/*
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111=head1 Hash Manipulation Functions
112
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113=for apidoc AmU||HEf_SVKEY
114This flag, used in the length slot of hash entries and magic structures,
d1be9408 115specifies the structure contains an C<SV*> pointer where a C<char*> pointer
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116is to be expected. (For information only--not to be used).
117
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118=head1 Handy Values
119
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120=for apidoc AmU||Nullhv
121Null HV pointer.
122
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123=head1 Hash Manipulation Functions
124
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125=for apidoc Am|char*|HvNAME|HV* stash
126Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>.
127
128=for apidoc Am|void*|HeKEY|HE* he
129Returns the actual pointer stored in the key slot of the hash entry. The
130pointer may be either C<char*> or C<SV*>, depending on the value of
131C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are
132usually preferable for finding the value of a key.
133
134=for apidoc Am|STRLEN|HeKLEN|HE* he
135If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
136holds an C<SV*> key. Otherwise, holds the actual length of the key. Can
137be assigned to. The C<HePV()> macro is usually preferable for finding key
138lengths.
139
140=for apidoc Am|SV*|HeVAL|HE* he
141Returns the value slot (type C<SV*>) stored in the hash entry.
142
143=for apidoc Am|U32|HeHASH|HE* he
144Returns the computed hash stored in the hash entry.
145
146=for apidoc Am|char*|HePV|HE* he|STRLEN len
147Returns the key slot of the hash entry as a C<char*> value, doing any
148necessary dereferencing of possibly C<SV*> keys. The length of the string
149is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do
150not care about what the length of the key is, you may use the global
151variable C<PL_na>, though this is rather less efficient than using a local
152variable. Remember though, that hash keys in perl are free to contain
153embedded nulls, so using C<strlen()> or similar is not a good way to find
154the length of hash keys. This is very similar to the C<SvPV()> macro
155described elsewhere in this document.
156
157=for apidoc Am|SV*|HeSVKEY|HE* he
158Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not
159contain an C<SV*> key.
160
161=for apidoc Am|SV*|HeSVKEY_force|HE* he
162Returns the key as an C<SV*>. Will create and return a temporary mortal
163C<SV*> if the hash entry contains only a C<char*> key.
164
165=for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv
166Sets the key to a given C<SV*>, taking care to set the appropriate flags to
167indicate the presence of an C<SV*> key, and returns the same
168C<SV*>.
169
170=cut
171*/
bf6bd887 172
bf5b86ae 173/* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
d1be9408 174#define HEf_SVKEY -2 /* hent_key is an SV* */
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175
176
79072805 177#define Nullhv Null(HV*)
4efcf9a2 178#define HvARRAY(hv) (*(HE***)&((XPVHV*) SvANY(hv))->xhv_array)
79072805 179#define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill
463ee0b2 180#define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max
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181#define HvRITER(hv) ((XPVHV*) SvANY(hv))->xhv_riter
182#define HvEITER(hv) ((XPVHV*) SvANY(hv))->xhv_eiter
183#define HvPMROOT(hv) ((XPVHV*) SvANY(hv))->xhv_pmroot
184#define HvNAME(hv) ((XPVHV*) SvANY(hv))->xhv_name
a0d0e21e 185
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186/* the number of keys (including any placeholers) */
187#define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys)
188
189/* The number of placeholders in the enumerated-keys hash */
205c8ad3 190#define XHvPLACEHOLDERS(xhv) ((xhv)->xhv_placeholders)
8aacddc1 191
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192/* the number of keys that exist() (i.e. excluding placeholders) */
193#define XHvUSEDKEYS(xhv) (XHvTOTALKEYS(xhv) - (IV)XHvPLACEHOLDERS(xhv))
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194
195/*
196 * HvKEYS gets the number of keys that actually exist(), and is provided
197 * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
198 * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
199 */
200#define HvKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
201#define HvUSEDKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
202#define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv))
203#define HvPLACEHOLDERS(hv) XHvPLACEHOLDERS((XPVHV*) SvANY(hv))
204
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205#define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS)
206#define HvSHAREKEYS_on(hv) (SvFLAGS(hv) |= SVphv_SHAREKEYS)
207#define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
208
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209/* This is an optimisation flag. It won't be set if all hash keys have a 0
210 * flag. Currently the only flags relate to utf8.
211 * Hence it won't be set if all keys are 8 bit only. It will be set if any key
212 * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading
213 * when retrieved during iteration. It may still be set when there are no longer
214 * any utf8 keys.
fdcd69b6 215 * See HVhek_ENABLEHVKFLAGS for the trigger.
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216 */
217#define HvHASKFLAGS(hv) (SvFLAGS(hv) & SVphv_HASKFLAGS)
218#define HvHASKFLAGS_on(hv) (SvFLAGS(hv) |= SVphv_HASKFLAGS)
219#define HvHASKFLAGS_off(hv) (SvFLAGS(hv) &= ~SVphv_HASKFLAGS)
574c8022 220
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221#define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL)
222#define HvLAZYDEL_on(hv) (SvFLAGS(hv) |= SVphv_LAZYDEL)
223#define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL)
224
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225#define HvREHASH(hv) (SvFLAGS(hv) & SVphv_REHASH)
226#define HvREHASH_on(hv) (SvFLAGS(hv) |= SVphv_REHASH)
227#define HvREHASH_off(hv) (SvFLAGS(hv) &= ~SVphv_REHASH)
228
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229/* Maybe amagical: */
230/* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */
231
232#define HV_AMAGIC(hv) (SvFLAGS(hv) & SVpgv_AM)
233#define HV_AMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_AM)
234#define HV_AMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_AM)
235
236/*
237#define HV_AMAGICbad(hv) (SvFLAGS(hv) & SVpgv_badAM)
238#define HV_badAMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_badAM)
239#define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
240*/
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241
242#define Nullhe Null(HE*)
243#define HeNEXT(he) (he)->hent_next
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244#define HeKEY_hek(he) (he)->hent_hek
245#define HeKEY(he) HEK_KEY(HeKEY_hek(he))
bbce6d69 246#define HeKEY_sv(he) (*(SV**)HeKEY(he))
ff68c719 247#define HeKLEN(he) HEK_LEN(HeKEY_hek(he))
da58a35d 248#define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he))
19692e8d 249#define HeKWASUTF8(he) HEK_WASUTF8(HeKEY_hek(he))
4b5190b5 250#define HeKREHASH(he) HEK_REHASH(HeKEY_hek(he))
da58a35d 251#define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
19692e8d 252#define HeKFLAGS(he) HEK_FLAGS(HeKEY_hek(he))
bf6bd887 253#define HeVAL(he) (he)->hent_val
ff68c719 254#define HeHASH(he) HEK_HASH(HeKEY_hek(he))
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255#define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \
256 SvPV(HeKEY_sv(he),lp) : \
257 (((lp = HeKLEN(he)) >= 0) ? \
258 HeKEY(he) : Nullch))
259
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260#define HeSVKEY(he) ((HeKEY(he) && \
261 HeKLEN(he) == HEf_SVKEY) ? \
262 HeKEY_sv(he) : Nullsv)
263
264#define HeSVKEY_force(he) (HeKEY(he) ? \
265 ((HeKLEN(he) == HEf_SVKEY) ? \
266 HeKEY_sv(he) : \
79cb57f6 267 sv_2mortal(newSVpvn(HeKEY(he), \
bbce6d69 268 HeKLEN(he)))) : \
3280af22 269 &PL_sv_undef)
1e422769 270#define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
bbce6d69 271
ff68c719 272#define Nullhek Null(HEK*)
71be2cbc 273#define HEK_BASESIZE STRUCT_OFFSET(HEK, hek_key[0])
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274#define HEK_HASH(hek) (hek)->hek_hash
275#define HEK_LEN(hek) (hek)->hek_len
276#define HEK_KEY(hek) (hek)->hek_key
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277#define HEK_FLAGS(hek) (*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1))
278
279#define HVhek_UTF8 0x01 /* Key is utf8 encoded. */
280#define HVhek_WASUTF8 0x02 /* Key is bytes here, but was supplied as utf8. */
4b5190b5 281#define HVhek_REHASH 0x04 /* This key is in an hv using a custom HASH . */
19692e8d 282#define HVhek_FREEKEY 0x100 /* Internal flag to say key is malloc()ed. */
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283#define HVhek_PLACEHOLD 0x200 /* Internal flag to create placeholder.
284 * (may change, but Storable is a core module) */
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285#define HVhek_MASK 0xFF
286
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287/* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as
288 HVhek_REHASH is only needed because the rehash flag has to be duplicated
289 into all keys as hv_iternext has no access to the hash flags. At this
290 point Storable's tests get upset, because sometimes hashes are "keyed"
291 and sometimes not, depending on the order of data insertion, and whether
292 it triggered rehashing. So currently HVhek_REHAS is exempt.
293*/
294
295#define HVhek_ENABLEHVKFLAGS (HVhek_MASK - HVhek_REHASH)
296
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297#define HEK_UTF8(hek) (HEK_FLAGS(hek) & HVhek_UTF8)
298#define HEK_UTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_UTF8)
299#define HEK_UTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_UTF8)
300#define HEK_WASUTF8(hek) (HEK_FLAGS(hek) & HVhek_WASUTF8)
301#define HEK_WASUTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_WASUTF8)
302#define HEK_WASUTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_WASUTF8)
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303#define HEK_REHASH(hek) (HEK_FLAGS(hek) & HVhek_REHASH)
304#define HEK_REHASH_on(hek) (HEK_FLAGS(hek) |= HVhek_REHASH)
d18c6117 305
5cbe4eec 306/* calculate HV array allocation */
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307#if defined(STRANGE_MALLOC) || defined(MYMALLOC)
308# define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
309#else
310# define MALLOC_OVERHEAD 16
311# define PERL_HV_ARRAY_ALLOC_BYTES(size) \
312 (((size) < 64) \
313 ? (size) * sizeof(HE*) \
314 : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
315#endif
37d85e3a 316
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317/* Flags for hv_iternext_flags. */
318#define HV_ITERNEXT_WANTPLACEHOLDERS 0x01 /* Don't skip placeholders. */
319
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320/* available as a function in hv.c */
321#define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
322#define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash)