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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 | */ |