3 * Copyright (c) 1991-2002, Larry Wall
5 * You may distribute under the terms of either the GNU General Public
6 * License or the Artistic License, as specified in the README file.
10 /* typedefs to eliminate some typing */
12 typedef struct hek HEK;
14 /* entry in hash value chain */
16 HE *hent_next; /* next entry in chain */
17 HEK *hent_hek; /* hash key */
18 SV *hent_val; /* scalar value that was hashed */
21 /* hash key -- defined separately for use as shared pointer */
23 U32 hek_hash; /* hash of key */
24 I32 hek_len; /* length of hash key */
25 char hek_key[1]; /* variable-length hash key */
29 /* This structure must match the beginning of struct xpvmg in sv.h. */
31 char * xhv_array; /* pointer to malloced string */
32 STRLEN xhv_fill; /* how full xhv_array currently is */
33 STRLEN xhv_max; /* subscript of last element of xhv_array */
34 IV xhv_keys; /* how many elements in the array */
35 NV xnv_nv; /* numeric value, if any */
36 #define xhv_placeholders xnv_nv
37 MAGIC* xmg_magic; /* magic for scalar array */
38 HV* xmg_stash; /* class package */
40 I32 xhv_riter; /* current root of iterator */
41 HE *xhv_eiter; /* current entry of iterator */
42 PMOP *xhv_pmroot; /* list of pm's for this package */
43 char *xhv_name; /* name, if a symbol table */
47 /* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins */
48 /* from requirements by Colin Plumb. */
49 /* (http://burtleburtle.net/bob/hash/doobs.html) */
50 #define PERL_HASH(hash,str,len) \
52 register const char *s_PeRlHaSh = str; \
53 register I32 i_PeRlHaSh = len; \
54 register U32 hash_PeRlHaSh = 0; \
55 while (i_PeRlHaSh--) { \
56 hash_PeRlHaSh += *s_PeRlHaSh++; \
57 hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
58 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
60 hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
61 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
62 (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
66 =head1 Hash Manipulation Functions
68 =for apidoc AmU||HEf_SVKEY
69 This flag, used in the length slot of hash entries and magic structures,
70 specifies the structure contains an C<SV*> pointer where a C<char*> pointer
71 is to be expected. (For information only--not to be used).
75 =for apidoc AmU||Nullhv
78 =head1 Hash Manipulation Functions
80 =for apidoc Am|char*|HvNAME|HV* stash
81 Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>.
83 =for apidoc Am|void*|HeKEY|HE* he
84 Returns the actual pointer stored in the key slot of the hash entry. The
85 pointer may be either C<char*> or C<SV*>, depending on the value of
86 C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are
87 usually preferable for finding the value of a key.
89 =for apidoc Am|STRLEN|HeKLEN|HE* he
90 If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
91 holds an C<SV*> key. Otherwise, holds the actual length of the key. Can
92 be assigned to. The C<HePV()> macro is usually preferable for finding key
95 =for apidoc Am|SV*|HeVAL|HE* he
96 Returns the value slot (type C<SV*>) stored in the hash entry.
98 =for apidoc Am|U32|HeHASH|HE* he
99 Returns the computed hash stored in the hash entry.
101 =for apidoc Am|char*|HePV|HE* he|STRLEN len
102 Returns the key slot of the hash entry as a C<char*> value, doing any
103 necessary dereferencing of possibly C<SV*> keys. The length of the string
104 is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do
105 not care about what the length of the key is, you may use the global
106 variable C<PL_na>, though this is rather less efficient than using a local
107 variable. Remember though, that hash keys in perl are free to contain
108 embedded nulls, so using C<strlen()> or similar is not a good way to find
109 the length of hash keys. This is very similar to the C<SvPV()> macro
110 described elsewhere in this document.
112 =for apidoc Am|SV*|HeSVKEY|HE* he
113 Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not
114 contain an C<SV*> key.
116 =for apidoc Am|SV*|HeSVKEY_force|HE* he
117 Returns the key as an C<SV*>. Will create and return a temporary mortal
118 C<SV*> if the hash entry contains only a C<char*> key.
120 =for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv
121 Sets the key to a given C<SV*>, taking care to set the appropriate flags to
122 indicate the presence of an C<SV*> key, and returns the same
128 /* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
129 #define HEf_SVKEY -2 /* hent_key is an SV* */
132 #define Nullhv Null(HV*)
133 #define HvARRAY(hv) (*(HE***)&((XPVHV*) SvANY(hv))->xhv_array)
134 #define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill
135 #define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max
136 #define HvRITER(hv) ((XPVHV*) SvANY(hv))->xhv_riter
137 #define HvEITER(hv) ((XPVHV*) SvANY(hv))->xhv_eiter
138 #define HvPMROOT(hv) ((XPVHV*) SvANY(hv))->xhv_pmroot
139 #define HvNAME(hv) ((XPVHV*) SvANY(hv))->xhv_name
141 /* the number of keys (including any placeholers) */
142 #define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys)
144 /* The number of placeholders in the enumerated-keys hash */
145 #define XHvPLACEHOLDERS(xhv) ((xhv)->xhv_placeholders)
147 /* the number of keys that exist() (i.e. excluding placeholders) */
148 #define XHvUSEDKEYS(xhv) (XHvTOTALKEYS(xhv) - (IV)XHvPLACEHOLDERS(xhv))
151 * HvKEYS gets the number of keys that actually exist(), and is provided
152 * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
153 * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
155 #define HvKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
156 #define HvUSEDKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
157 #define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv))
158 #define HvPLACEHOLDERS(hv) XHvPLACEHOLDERS((XPVHV*) SvANY(hv))
161 #define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS)
162 #define HvSHAREKEYS_on(hv) (SvFLAGS(hv) |= SVphv_SHAREKEYS)
163 #define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
165 #define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL)
166 #define HvLAZYDEL_on(hv) (SvFLAGS(hv) |= SVphv_LAZYDEL)
167 #define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL)
169 /* Maybe amagical: */
170 /* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */
172 #define HV_AMAGIC(hv) (SvFLAGS(hv) & SVpgv_AM)
173 #define HV_AMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_AM)
174 #define HV_AMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_AM)
177 #define HV_AMAGICbad(hv) (SvFLAGS(hv) & SVpgv_badAM)
178 #define HV_badAMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_badAM)
179 #define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
182 #define Nullhe Null(HE*)
183 #define HeNEXT(he) (he)->hent_next
184 #define HeKEY_hek(he) (he)->hent_hek
185 #define HeKEY(he) HEK_KEY(HeKEY_hek(he))
186 #define HeKEY_sv(he) (*(SV**)HeKEY(he))
187 #define HeKLEN(he) HEK_LEN(HeKEY_hek(he))
188 #define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he))
189 #define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
190 #define HeVAL(he) (he)->hent_val
191 #define HeHASH(he) HEK_HASH(HeKEY_hek(he))
192 #define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \
193 SvPV(HeKEY_sv(he),lp) : \
194 (((lp = HeKLEN(he)) >= 0) ? \
197 #define HeSVKEY(he) ((HeKEY(he) && \
198 HeKLEN(he) == HEf_SVKEY) ? \
199 HeKEY_sv(he) : Nullsv)
201 #define HeSVKEY_force(he) (HeKEY(he) ? \
202 ((HeKLEN(he) == HEf_SVKEY) ? \
204 sv_2mortal(newSVpvn(HeKEY(he), \
207 #define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
209 #define Nullhek Null(HEK*)
210 #define HEK_BASESIZE STRUCT_OFFSET(HEK, hek_key[0])
211 #define HEK_HASH(hek) (hek)->hek_hash
212 #define HEK_LEN(hek) (hek)->hek_len
213 #define HEK_KEY(hek) (hek)->hek_key
214 #define HEK_UTF8(hek) (*(HEK_KEY(hek)+HEK_LEN(hek)))
216 /* calculate HV array allocation */
217 #if defined(STRANGE_MALLOC) || defined(MYMALLOC)
218 # define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
220 # define MALLOC_OVERHEAD 16
221 # define PERL_HV_ARRAY_ALLOC_BYTES(size) \
223 ? (size) * sizeof(HE*) \
224 : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
227 /* available as a function in hv.c */
228 #define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
229 #define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash)