1 /* hv.h 2 * 3 * Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999, 4 * 2000, 2001, 2002, by Larry Wall and others 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 * 9 */ 10 11 /* typedefs to eliminate some typing */ 12 typedef struct he HE; 13 typedef struct hek HEK; 14 15 /* entry in hash value chain */ 16 struct he { 17 HE *hent_next; /* next entry in chain */ 18 HEK *hent_hek; /* hash key */ 19 SV *hent_val; /* scalar value that was hashed */ 20 }; 21 22 /* hash key -- defined separately for use as shared pointer */ 23 struct hek { 24 U32 hek_hash; /* hash of key */ 25 I32 hek_len; /* length of hash key */ 26 char hek_key[1]; /* variable-length hash key */ 27 /* the hash-key is \0-terminated */ 28 /* after the \0 there is a byte for flags, such as whether the key 29 is UTF-8 */ 30 }; 31 32 /* hash structure: */ 33 /* This structure must match the beginning of struct xpvmg in sv.h. */ 34 struct xpvhv { 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 */ 38 IV xhv_keys; /* how many elements in the array */ 39 NV xnv_nv; /* numeric value, if any */ 40 #define xhv_placeholders xnv_nv 41 MAGIC* xmg_magic; /* magic for scalar array */ 42 HV* xmg_stash; /* class package */ 43 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 */ 48 }; 49 50 /* hash a key */ 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" 59 * 60 * The "hash seed" feature was added in Perl 5.8.1 to perturb the results 61 * to avoid "algorithmic complexity attacks". 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()). 68 */ 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 75 #endif 76 #define PERL_HASH(hash,str,len) \ 77 STMT_START { \ 78 register const char *s_PeRlHaSh_tmp = str; \ 79 register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \ 80 register I32 i_PeRlHaSh = len; \ 81 register U32 hash_PeRlHaSh = PERL_HASH_SEED; \ 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); \ 89 (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \ 90 } STMT_END 91 92 /* Only hv.c and mod_perl should be doing this. */ 93 #ifdef PERL_HASH_INTERNAL_ACCESS 94 #define PERL_HASH_INTERNAL(hash,str,len) \ 95 STMT_START { \ 96 register const char *s_PeRlHaSh_tmp = str; \ 97 register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \ 98 register I32 i_PeRlHaSh = len; \ 99 register U32 hash_PeRlHaSh = PL_rehash_seed; \ 100 while (i_PeRlHaSh--) { \ 101 hash_PeRlHaSh += *s_PeRlHaSh++; \ 102 hash_PeRlHaSh += (hash_PeRlHaSh << 10); \ 103 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \ 104 } \ 105 hash_PeRlHaSh += (hash_PeRlHaSh << 3); \ 106 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \ 107 (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \ 108 } STMT_END 109 #endif 110 111 /* 112 =head1 Hash Manipulation Functions 113 114 =for apidoc AmU||HEf_SVKEY 115 This flag, used in the length slot of hash entries and magic structures, 116 specifies the structure contains an C<SV*> pointer where a C<char*> pointer 117 is to be expected. (For information only--not to be used). 118 119 =head1 Handy Values 120 121 =for apidoc AmU||Nullhv 122 Null HV pointer. 123 124 =head1 Hash Manipulation Functions 125 126 =for apidoc Am|char*|HvNAME|HV* stash 127 Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>. 128 129 =for apidoc Am|void*|HeKEY|HE* he 130 Returns the actual pointer stored in the key slot of the hash entry. The 131 pointer may be either C<char*> or C<SV*>, depending on the value of 132 C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are 133 usually preferable for finding the value of a key. 134 135 =for apidoc Am|STRLEN|HeKLEN|HE* he 136 If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry 137 holds an C<SV*> key. Otherwise, holds the actual length of the key. Can 138 be assigned to. The C<HePV()> macro is usually preferable for finding key 139 lengths. 140 141 =for apidoc Am|SV*|HeVAL|HE* he 142 Returns the value slot (type C<SV*>) stored in the hash entry. 143 144 =for apidoc Am|U32|HeHASH|HE* he 145 Returns the computed hash stored in the hash entry. 146 147 =for apidoc Am|char*|HePV|HE* he|STRLEN len 148 Returns the key slot of the hash entry as a C<char*> value, doing any 149 necessary dereferencing of possibly C<SV*> keys. The length of the string 150 is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do 151 not care about what the length of the key is, you may use the global 152 variable C<PL_na>, though this is rather less efficient than using a local 153 variable. Remember though, that hash keys in perl are free to contain 154 embedded nulls, so using C<strlen()> or similar is not a good way to find 155 the length of hash keys. This is very similar to the C<SvPV()> macro 156 described elsewhere in this document. 157 158 =for apidoc Am|SV*|HeSVKEY|HE* he 159 Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not 160 contain an C<SV*> key. 161 162 =for apidoc Am|SV*|HeSVKEY_force|HE* he 163 Returns the key as an C<SV*>. Will create and return a temporary mortal 164 C<SV*> if the hash entry contains only a C<char*> key. 165 166 =for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv 167 Sets the key to a given C<SV*>, taking care to set the appropriate flags to 168 indicate the presence of an C<SV*> key, and returns the same 169 C<SV*>. 170 171 =cut 172 */ 173 174 /* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */ 175 #define HEf_SVKEY -2 /* hent_key is an SV* */ 176 177 178 #define Nullhv Null(HV*) 179 #define HvARRAY(hv) (*(HE***)&((XPVHV*) SvANY(hv))->xhv_array) 180 #define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill 181 #define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max 182 #define HvRITER(hv) ((XPVHV*) SvANY(hv))->xhv_riter 183 #define HvEITER(hv) ((XPVHV*) SvANY(hv))->xhv_eiter 184 #define HvPMROOT(hv) ((XPVHV*) SvANY(hv))->xhv_pmroot 185 #define HvNAME(hv) ((XPVHV*) SvANY(hv))->xhv_name 186 187 /* the number of keys (including any placeholers) */ 188 #define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys) 189 190 /* The number of placeholders in the enumerated-keys hash */ 191 #define XHvPLACEHOLDERS(xhv) ((xhv)->xhv_placeholders) 192 193 /* the number of keys that exist() (i.e. excluding placeholders) */ 194 #define XHvUSEDKEYS(xhv) (XHvTOTALKEYS(xhv) - (IV)XHvPLACEHOLDERS(xhv)) 195 196 /* 197 * HvKEYS gets the number of keys that actually exist(), and is provided 198 * for backwards compatibility with old XS code. The core uses HvUSEDKEYS 199 * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders) 200 */ 201 #define HvKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv)) 202 #define HvUSEDKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv)) 203 #define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv)) 204 #define HvPLACEHOLDERS(hv) XHvPLACEHOLDERS((XPVHV*) SvANY(hv)) 205 206 #define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS) 207 #define HvSHAREKEYS_on(hv) (SvFLAGS(hv) |= SVphv_SHAREKEYS) 208 #define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS) 209 210 /* This is an optimisation flag. It won't be set if all hash keys have a 0 211 * flag. Currently the only flags relate to utf8. 212 * Hence it won't be set if all keys are 8 bit only. It will be set if any key 213 * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading 214 * when retrieved during iteration. It may still be set when there are no longer 215 * any utf8 keys. 216 * See HVhek_ENABLEHVKFLAGS for the trigger. 217 */ 218 #define HvHASKFLAGS(hv) (SvFLAGS(hv) & SVphv_HASKFLAGS) 219 #define HvHASKFLAGS_on(hv) (SvFLAGS(hv) |= SVphv_HASKFLAGS) 220 #define HvHASKFLAGS_off(hv) (SvFLAGS(hv) &= ~SVphv_HASKFLAGS) 221 222 #define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL) 223 #define HvLAZYDEL_on(hv) (SvFLAGS(hv) |= SVphv_LAZYDEL) 224 #define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL) 225 226 #define HvREHASH(hv) (SvFLAGS(hv) & SVphv_REHASH) 227 #define HvREHASH_on(hv) (SvFLAGS(hv) |= SVphv_REHASH) 228 #define HvREHASH_off(hv) (SvFLAGS(hv) &= ~SVphv_REHASH) 229 230 /* Maybe amagical: */ 231 /* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */ 232 233 #define HV_AMAGIC(hv) (SvFLAGS(hv) & SVpgv_AM) 234 #define HV_AMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_AM) 235 #define HV_AMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_AM) 236 237 /* 238 #define HV_AMAGICbad(hv) (SvFLAGS(hv) & SVpgv_badAM) 239 #define HV_badAMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_badAM) 240 #define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM) 241 */ 242 243 #define Nullhe Null(HE*) 244 #define HeNEXT(he) (he)->hent_next 245 #define HeKEY_hek(he) (he)->hent_hek 246 #define HeKEY(he) HEK_KEY(HeKEY_hek(he)) 247 #define HeKEY_sv(he) (*(SV**)HeKEY(he)) 248 #define HeKLEN(he) HEK_LEN(HeKEY_hek(he)) 249 #define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he)) 250 #define HeKWASUTF8(he) HEK_WASUTF8(HeKEY_hek(he)) 251 #define HeKREHASH(he) HEK_REHASH(HeKEY_hek(he)) 252 #define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he)) 253 #define HeKFLAGS(he) HEK_FLAGS(HeKEY_hek(he)) 254 #define HeVAL(he) (he)->hent_val 255 #define HeHASH(he) HEK_HASH(HeKEY_hek(he)) 256 #define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \ 257 SvPV(HeKEY_sv(he),lp) : \ 258 (((lp = HeKLEN(he)) >= 0) ? \ 259 HeKEY(he) : Nullch)) 260 261 #define HeSVKEY(he) ((HeKEY(he) && \ 262 HeKLEN(he) == HEf_SVKEY) ? \ 263 HeKEY_sv(he) : Nullsv) 264 265 #define HeSVKEY_force(he) (HeKEY(he) ? \ 266 ((HeKLEN(he) == HEf_SVKEY) ? \ 267 HeKEY_sv(he) : \ 268 sv_2mortal(newSVpvn(HeKEY(he), \ 269 HeKLEN(he)))) : \ 270 &PL_sv_undef) 271 #define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv)) 272 273 #define Nullhek Null(HEK*) 274 #define HEK_BASESIZE STRUCT_OFFSET(HEK, hek_key[0]) 275 #define HEK_HASH(hek) (hek)->hek_hash 276 #define HEK_LEN(hek) (hek)->hek_len 277 #define HEK_KEY(hek) (hek)->hek_key 278 #define HEK_FLAGS(hek) (*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1)) 279 280 #define HVhek_UTF8 0x01 /* Key is utf8 encoded. */ 281 #define HVhek_WASUTF8 0x02 /* Key is bytes here, but was supplied as utf8. */ 282 #define HVhek_REHASH 0x04 /* This key is in an hv using a custom HASH . */ 283 #define HVhek_FREEKEY 0x100 /* Internal flag to say key is malloc()ed. */ 284 #define HVhek_PLACEHOLD 0x200 /* Internal flag to create placeholder. 285 * (may change, but Storable is a core module) */ 286 #define HVhek_MASK 0xFF 287 288 /* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as 289 HVhek_REHASH is only needed because the rehash flag has to be duplicated 290 into all keys as hv_iternext has no access to the hash flags. At this 291 point Storable's tests get upset, because sometimes hashes are "keyed" 292 and sometimes not, depending on the order of data insertion, and whether 293 it triggered rehashing. So currently HVhek_REHAS is exempt. 294 */ 295 296 #define HVhek_ENABLEHVKFLAGS (HVhek_MASK - HVhek_REHASH) 297 298 #define HEK_UTF8(hek) (HEK_FLAGS(hek) & HVhek_UTF8) 299 #define HEK_UTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_UTF8) 300 #define HEK_UTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_UTF8) 301 #define HEK_WASUTF8(hek) (HEK_FLAGS(hek) & HVhek_WASUTF8) 302 #define HEK_WASUTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_WASUTF8) 303 #define HEK_WASUTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_WASUTF8) 304 #define HEK_REHASH(hek) (HEK_FLAGS(hek) & HVhek_REHASH) 305 #define HEK_REHASH_on(hek) (HEK_FLAGS(hek) |= HVhek_REHASH) 306 307 /* calculate HV array allocation */ 308 #if defined(STRANGE_MALLOC) || defined(MYMALLOC) 309 # define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*)) 310 #else 311 # define MALLOC_OVERHEAD 16 312 # define PERL_HV_ARRAY_ALLOC_BYTES(size) \ 313 (((size) < 64) \ 314 ? (size) * sizeof(HE*) \ 315 : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD) 316 #endif 317 318 /* Flags for hv_iternext_flags. */ 319 #define HV_ITERNEXT_WANTPLACEHOLDERS 0x01 /* Don't skip placeholders. */ 320 321 /* available as a function in hv.c */ 322 #define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash)) 323 #define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash) 324