lib/perl5/5.8.8/msys/CORE/hv.h

   1 /*    hv.h
   2  *
   3  *    Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999,
   4  *    2000, 2001, 2002, 2005, 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 unsigned, 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 perl.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, or NULL if C<stash> isn't a stash.
 128 See C<SvSTASH>, C<CvSTASH>.
 129
 130 =for apidoc Am|void*|HeKEY|HE* he
 131 Returns the actual pointer stored in the key slot of the hash entry. The
 132 pointer may be either C<char*> or C<SV*>, depending on the value of
 133 C<HeKLEN()>.  Can be assigned to.  The C<HePV()> or C<HeSVKEY()> macros are
 134 usually preferable for finding the value of a key.
 135
 136 =for apidoc Am|STRLEN|HeKLEN|HE* he
 137 If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
 138 holds an C<SV*> key.  Otherwise, holds the actual length of the key.  Can
 139 be assigned to. The C<HePV()> macro is usually preferable for finding key
 140 lengths.
 141
 142 =for apidoc Am|SV*|HeVAL|HE* he
 143 Returns the value slot (type C<SV*>) stored in the hash entry.
 144
 145 =for apidoc Am|U32|HeHASH|HE* he
 146 Returns the computed hash stored in the hash entry.
 147
 148 =for apidoc Am|char*|HePV|HE* he|STRLEN len
 149 Returns the key slot of the hash entry as a C<char*> value, doing any
 150 necessary dereferencing of possibly C<SV*> keys.  The length of the string
 151 is placed in C<len> (this is a macro, so do I<not> use C<&len>).  If you do
 152 not care about what the length of the key is, you may use the global
 153 variable C<PL_na>, though this is rather less efficient than using a local
 154 variable.  Remember though, that hash keys in perl are free to contain
 155 embedded nulls, so using C<strlen()> or similar is not a good way to find
 156 the length of hash keys. This is very similar to the C<SvPV()> macro
 157 described elsewhere in this document.
 158
 159 =for apidoc Am|SV*|HeSVKEY|HE* he
 160 Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not
 161 contain an C<SV*> key.
 162
 163 =for apidoc Am|SV*|HeSVKEY_force|HE* he
 164 Returns the key as an C<SV*>.  Will create and return a temporary mortal
 165 C<SV*> if the hash entry contains only a C<char*> key.
 166
 167 =for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv
 168 Sets the key to a given C<SV*>, taking care to set the appropriate flags to
 169 indicate the presence of an C<SV*> key, and returns the same
 170 C<SV*>.
 171
 172 =cut
 173 */
 174
 175 /* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
 176 #define HEf_SVKEY       -2      /* hent_key is an SV* */
 177
 178
 179 #define Nullhv Null(HV*)
 180 #define HvARRAY(hv)     (*(HE***)&((XPVHV*)  SvANY(hv))->xhv_array)
 181 #define HvFILL(hv)      ((XPVHV*)  SvANY(hv))->xhv_fill
 182 #define HvMAX(hv)       ((XPVHV*)  SvANY(hv))->xhv_max
 183 #define HvRITER(hv)     ((XPVHV*)  SvANY(hv))->xhv_riter
 184 #define HvRITER_get(hv) (0 + ((XPVHV*)  SvANY(hv))->xhv_riter)
 185 #define HvRITER_set(hv,r)       (HvRITER(hv) = (r))
 186 #define HvEITER(hv)     ((XPVHV*)  SvANY(hv))->xhv_eiter
 187 #define HvEITER_get(hv) (0 + ((XPVHV*)  SvANY(hv))->xhv_eiter)
 188 #define HvEITER_set(hv,e)       (HvEITER(hv) = (e))
 189 #define HvPMROOT(hv)    ((XPVHV*)  SvANY(hv))->xhv_pmroot
 190 #define HvNAME(hv)      ((XPVHV*)  SvANY(hv))->xhv_name
 191 /* FIXME - all of these should use a UTF8 aware API, which should also involve
 192    getting the length. */
 193 #define HvNAME_get(hv)  (0 + ((XPVHV*)  SvANY(hv))->xhv_name)
 194 #define hv_name_set(hv,name,length,flags) \
 195     (HvNAME((hv)) = (name) ? savepvn(name, length) : 0)
 196
 197 /* the number of keys (including any placeholers) */
 198 #define XHvTOTALKEYS(xhv)       ((xhv)->xhv_keys)
 199
 200 /* The number of placeholders in the enumerated-keys hash */
 201 #define XHvPLACEHOLDERS(xhv)    ((xhv)->xhv_placeholders)
 202
 203 /* the number of keys that exist() (i.e. excluding placeholders) */
 204 #define XHvUSEDKEYS(xhv)      (XHvTOTALKEYS(xhv) - (IV)XHvPLACEHOLDERS(xhv))
 205
 206 /*
 207  * HvKEYS gets the number of keys that actually exist(), and is provided
 208  * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
 209  * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
 210  */
 211 #define HvKEYS(hv)              XHvUSEDKEYS((XPVHV*)  SvANY(hv))
 212 #define HvUSEDKEYS(hv)          XHvUSEDKEYS((XPVHV*)  SvANY(hv))
 213 #define HvTOTALKEYS(hv)         XHvTOTALKEYS((XPVHV*)  SvANY(hv))
 214 #define HvPLACEHOLDERS(hv)      (XHvPLACEHOLDERS((XPVHV*)  SvANY(hv)))
 215 #define HvPLACEHOLDERS_get(hv)  (0 + XHvPLACEHOLDERS((XPVHV*)  SvANY(hv)))
 216 #define HvPLACEHOLDERS_set(hv, p)       \
 217         (XHvPLACEHOLDERS((XPVHV*)  SvANY(hv)) = (p))
 218
 219 #define HvSHAREKEYS(hv)         (SvFLAGS(hv) & SVphv_SHAREKEYS)
 220 #define HvSHAREKEYS_on(hv)      (SvFLAGS(hv) |= SVphv_SHAREKEYS)
 221 #define HvSHAREKEYS_off(hv)     (SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
 222
 223 /* This is an optimisation flag. It won't be set if all hash keys have a 0
 224  * flag. Currently the only flags relate to utf8.
 225  * Hence it won't be set if all keys are 8 bit only. It will be set if any key
 226  * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading
 227  * when retrieved during iteration. It may still be set when there are no longer
 228  * any utf8 keys.
 229  * See HVhek_ENABLEHVKFLAGS for the trigger.
 230  */
 231 #define HvHASKFLAGS(hv)         (SvFLAGS(hv) & SVphv_HASKFLAGS)
 232 #define HvHASKFLAGS_on(hv)      (SvFLAGS(hv) |= SVphv_HASKFLAGS)
 233 #define HvHASKFLAGS_off(hv)     (SvFLAGS(hv) &= ~SVphv_HASKFLAGS)
 234
 235 #define HvLAZYDEL(hv)           (SvFLAGS(hv) & SVphv_LAZYDEL)
 236 #define HvLAZYDEL_on(hv)        (SvFLAGS(hv) |= SVphv_LAZYDEL)
 237 #define HvLAZYDEL_off(hv)       (SvFLAGS(hv) &= ~SVphv_LAZYDEL)
 238
 239 #define HvREHASH(hv)            (SvFLAGS(hv) & SVphv_REHASH)
 240 #define HvREHASH_on(hv)         (SvFLAGS(hv) |= SVphv_REHASH)
 241 #define HvREHASH_off(hv)        (SvFLAGS(hv) &= ~SVphv_REHASH)
 242
 243 /* Maybe amagical: */
 244 /* #define HV_AMAGICmb(hv)      (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */
 245
 246 #define HV_AMAGIC(hv)        (SvFLAGS(hv) &   SVpgv_AM)
 247 #define HV_AMAGIC_on(hv)     (SvFLAGS(hv) |=  SVpgv_AM)
 248 #define HV_AMAGIC_off(hv)    (SvFLAGS(hv) &= ~SVpgv_AM)
 249
 250 /*
 251 #define HV_AMAGICbad(hv)     (SvFLAGS(hv) & SVpgv_badAM)
 252 #define HV_badAMAGIC_on(hv)  (SvFLAGS(hv) |= SVpgv_badAM)
 253 #define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
 254 */
 255
 256 #define Nullhe Null(HE*)
 257 #define HeNEXT(he)              (he)->hent_next
 258 #define HeKEY_hek(he)           (he)->hent_hek
 259 #define HeKEY(he)               HEK_KEY(HeKEY_hek(he))
 260 #define HeKEY_sv(he)            (*(SV**)HeKEY(he))
 261 #define HeKLEN(he)              HEK_LEN(HeKEY_hek(he))
 262 #define HeKUTF8(he)  HEK_UTF8(HeKEY_hek(he))
 263 #define HeKWASUTF8(he)  HEK_WASUTF8(HeKEY_hek(he))
 264 #define HeKREHASH(he)  HEK_REHASH(HeKEY_hek(he))
 265 #define HeKLEN_UTF8(he)  (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
 266 #define HeKFLAGS(he)  HEK_FLAGS(HeKEY_hek(he))
 267 #define HeVAL(he)               (he)->hent_val
 268 #define HeHASH(he)              HEK_HASH(HeKEY_hek(he))
 269 #define HePV(he,lp)             ((HeKLEN(he) == HEf_SVKEY) ?            \
 270                                  SvPV(HeKEY_sv(he),lp) :                \
 271                                  (((lp = HeKLEN(he)) >= 0) ?            \
 272                                   HeKEY(he) : Nullch))
 273
 274 #define HeSVKEY(he)             ((HeKEY(he) &&                          \
 275                                   HeKLEN(he) == HEf_SVKEY) ?            \
 276                                  HeKEY_sv(he) : Nullsv)
 277
 278 #define HeSVKEY_force(he)       (HeKEY(he) ?                            \
 279                                  ((HeKLEN(he) == HEf_SVKEY) ?           \
 280                                   HeKEY_sv(he) :                        \
 281                                   sv_2mortal(newSVpvn(HeKEY(he),        \
 282                                                      HeKLEN(he)))) :    \
 283                                  &PL_sv_undef)
 284 #define HeSVKEY_set(he,sv)      ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
 285
 286 #define Nullhek Null(HEK*)
 287 #define HEK_BASESIZE            STRUCT_OFFSET(HEK, hek_key[0])
 288 #define HEK_HASH(hek)           (hek)->hek_hash
 289 #define HEK_LEN(hek)            (hek)->hek_len
 290 #define HEK_KEY(hek)            (hek)->hek_key
 291 #define HEK_FLAGS(hek)  (*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1))
 292
 293 #define HVhek_UTF8      0x01 /* Key is utf8 encoded. */
 294 #define HVhek_WASUTF8   0x02 /* Key is bytes here, but was supplied as utf8. */
 295 #define HVhek_REHASH    0x04 /* This key is in an hv using a custom HASH . */
 296 #define HVhek_FREEKEY   0x100 /* Internal flag to say key is malloc()ed.  */
 297 #define HVhek_PLACEHOLD 0x200 /* Internal flag to create placeholder.
 298                                * (may change, but Storable is a core module) */
 299 #define HVhek_MASK      0xFF
 300
 301 /* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as
 302    HVhek_REHASH is only needed because the rehash flag has to be duplicated
 303    into all keys as hv_iternext has no access to the hash flags. At this
 304    point Storable's tests get upset, because sometimes hashes are "keyed"
 305    and sometimes not, depending on the order of data insertion, and whether
 306    it triggered rehashing. So currently HVhek_REHAS is exempt.
 307 */
 308
 309 #define HVhek_ENABLEHVKFLAGS    (HVhek_MASK - HVhek_REHASH)
 310
 311 #define HEK_UTF8(hek)           (HEK_FLAGS(hek) & HVhek_UTF8)
 312 #define HEK_UTF8_on(hek)        (HEK_FLAGS(hek) |= HVhek_UTF8)
 313 #define HEK_UTF8_off(hek)       (HEK_FLAGS(hek) &= ~HVhek_UTF8)
 314 #define HEK_WASUTF8(hek)        (HEK_FLAGS(hek) & HVhek_WASUTF8)
 315 #define HEK_WASUTF8_on(hek)     (HEK_FLAGS(hek) |= HVhek_WASUTF8)
 316 #define HEK_WASUTF8_off(hek)    (HEK_FLAGS(hek) &= ~HVhek_WASUTF8)
 317 #define HEK_REHASH(hek)         (HEK_FLAGS(hek) & HVhek_REHASH)
 318 #define HEK_REHASH_on(hek)      (HEK_FLAGS(hek) |= HVhek_REHASH)
 319
 320 /* calculate HV array allocation */
 321 #ifndef PERL_USE_LARGE_HV_ALLOC
 322 /* Default to allocating the correct size - default to assuming that malloc()
 323    is not broken and is efficient at allocating blocks sized at powers-of-two.
 324 */
 325 #  define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
 326 #else
 327 #  define MALLOC_OVERHEAD 16
 328 #  define PERL_HV_ARRAY_ALLOC_BYTES(size) \
 329                         (((size) < 64)                                  \
 330                          ? (size) * sizeof(HE*)                         \
 331                          : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
 332 #endif
 333
 334 /* Flags for hv_iternext_flags.  */
 335 #define HV_ITERNEXT_WANTPLACEHOLDERS    0x01    /* Don't skip placeholders.  */
 336
 337 /* available as a function in hv.c */
 338 #define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
 339 #define sharepvn(sv, len, hash)      Perl_sharepvn(sv, len, hash)
 340
 341 /*
 342  * Local variables:
 343  * c-indentation-style: bsd
 344  * c-basic-offset: 4
 345  * indent-tabs-mode: t
 346  * End:
 347  *
 348  * ex: set ts=8 sts=4 sw=4 noet:
 349  */