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[perl5.git] / hv.h
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a0d0e21e 1/* hv.h
79072805 2 *
bc89e66f 3 * Copyright (c) 1991-2001, Larry Wall
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4 *
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.
7 *
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8 */
9
5cbe4eec 10/* typedefs to eliminate some typing */
79072805 11typedef struct he HE;
ff68c719 12typedef struct hek HEK;
79072805 13
5cbe4eec 14/* entry in hash value chain */
79072805 15struct he {
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16 HE *hent_next; /* next entry in chain */
17 HEK *hent_hek; /* hash key */
18 SV *hent_val; /* scalar value that was hashed */
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19};
20
5cbe4eec 21/* hash key -- defined separately for use as shared pointer */
ff68c719 22struct hek {
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23 U32 hek_hash; /* hash of key */
24 I32 hek_len; /* length of hash key */
25 char hek_key[1]; /* variable-length hash key */
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26};
27
5cbe4eec 28/* hash structure: */
6ee623d5 29/* This structure must match the beginning of struct xpvmg in sv.h. */
79072805 30struct xpvhv {
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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 */
6ee623d5 34 IV xhv_keys; /* how many elements in the array */
65202027 35 NV xnv_nv; /* numeric value, if any */
8aacddc1 36#define xhv_placeholders xnv_nv
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37 MAGIC* xmg_magic; /* magic for scalar array */
38 HV* xmg_stash; /* class package */
39
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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 */
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44};
45
5cbe4eec 46/* hash a key */
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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) */
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50#define PERL_HASH(hash,str,len) \
51 STMT_START { \
08105a92 52 register const char *s_PeRlHaSh = str; \
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53 register I32 i_PeRlHaSh = len; \
54 register U32 hash_PeRlHaSh = 0; \
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55 while (i_PeRlHaSh--) { \
56 hash_PeRlHaSh += *s_PeRlHaSh++; \
57 hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
58 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
59 } \
60 hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
61 hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
4fee5c71 62 (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
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63 } STMT_END
64
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65/*
66=for apidoc AmU||HEf_SVKEY
67This flag, used in the length slot of hash entries and magic structures,
d1be9408 68specifies the structure contains an C<SV*> pointer where a C<char*> pointer
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69is to be expected. (For information only--not to be used).
70
71=for apidoc AmU||Nullhv
72Null HV pointer.
73
74=for apidoc Am|char*|HvNAME|HV* stash
75Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>.
76
77=for apidoc Am|void*|HeKEY|HE* he
78Returns the actual pointer stored in the key slot of the hash entry. The
79pointer may be either C<char*> or C<SV*>, depending on the value of
80C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are
81usually preferable for finding the value of a key.
82
83=for apidoc Am|STRLEN|HeKLEN|HE* he
84If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry
85holds an C<SV*> key. Otherwise, holds the actual length of the key. Can
86be assigned to. The C<HePV()> macro is usually preferable for finding key
87lengths.
88
89=for apidoc Am|SV*|HeVAL|HE* he
90Returns the value slot (type C<SV*>) stored in the hash entry.
91
92=for apidoc Am|U32|HeHASH|HE* he
93Returns the computed hash stored in the hash entry.
94
95=for apidoc Am|char*|HePV|HE* he|STRLEN len
96Returns the key slot of the hash entry as a C<char*> value, doing any
97necessary dereferencing of possibly C<SV*> keys. The length of the string
98is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do
99not care about what the length of the key is, you may use the global
100variable C<PL_na>, though this is rather less efficient than using a local
101variable. Remember though, that hash keys in perl are free to contain
102embedded nulls, so using C<strlen()> or similar is not a good way to find
103the length of hash keys. This is very similar to the C<SvPV()> macro
104described elsewhere in this document.
105
106=for apidoc Am|SV*|HeSVKEY|HE* he
107Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not
108contain an C<SV*> key.
109
110=for apidoc Am|SV*|HeSVKEY_force|HE* he
111Returns the key as an C<SV*>. Will create and return a temporary mortal
112C<SV*> if the hash entry contains only a C<char*> key.
113
114=for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv
115Sets the key to a given C<SV*>, taking care to set the appropriate flags to
116indicate the presence of an C<SV*> key, and returns the same
117C<SV*>.
118
119=cut
120*/
bf6bd887 121
bf5b86ae 122/* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
d1be9408 123#define HEf_SVKEY -2 /* hent_key is an SV* */
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124
125
79072805 126#define Nullhv Null(HV*)
4efcf9a2 127#define HvARRAY(hv) (*(HE***)&((XPVHV*) SvANY(hv))->xhv_array)
79072805 128#define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill
463ee0b2 129#define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max
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130#define HvRITER(hv) ((XPVHV*) SvANY(hv))->xhv_riter
131#define HvEITER(hv) ((XPVHV*) SvANY(hv))->xhv_eiter
132#define HvPMROOT(hv) ((XPVHV*) SvANY(hv))->xhv_pmroot
133#define HvNAME(hv) ((XPVHV*) SvANY(hv))->xhv_name
a0d0e21e 134
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135/* the number of keys (including any placeholers) */
136#define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys)
137
138/* The number of placeholders in the enumerated-keys hash */
205c8ad3 139#define XHvPLACEHOLDERS(xhv) ((xhv)->xhv_placeholders)
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140
141/* the number of keys that exist() (i.e. excluding placeholers) */
142#define XHvUSEDKEYS(xhv) (XHvTOTALKEYS(xhv) - XHvPLACEHOLDERS(xhv))
143
144/*
145 * HvKEYS gets the number of keys that actually exist(), and is provided
146 * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
147 * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
148 */
149#define HvKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
150#define HvUSEDKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
151#define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv))
152#define HvPLACEHOLDERS(hv) XHvPLACEHOLDERS((XPVHV*) SvANY(hv))
153
154
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155#define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS)
156#define HvSHAREKEYS_on(hv) (SvFLAGS(hv) |= SVphv_SHAREKEYS)
157#define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
158
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159#define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL)
160#define HvLAZYDEL_on(hv) (SvFLAGS(hv) |= SVphv_LAZYDEL)
161#define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL)
162
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163/* Maybe amagical: */
164/* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */
165
166#define HV_AMAGIC(hv) (SvFLAGS(hv) & SVpgv_AM)
167#define HV_AMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_AM)
168#define HV_AMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_AM)
169
170/*
171#define HV_AMAGICbad(hv) (SvFLAGS(hv) & SVpgv_badAM)
172#define HV_badAMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_badAM)
173#define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM)
174*/
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175
176#define Nullhe Null(HE*)
177#define HeNEXT(he) (he)->hent_next
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178#define HeKEY_hek(he) (he)->hent_hek
179#define HeKEY(he) HEK_KEY(HeKEY_hek(he))
bbce6d69 180#define HeKEY_sv(he) (*(SV**)HeKEY(he))
ff68c719 181#define HeKLEN(he) HEK_LEN(HeKEY_hek(he))
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182#define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he))
183#define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
bf6bd887 184#define HeVAL(he) (he)->hent_val
ff68c719 185#define HeHASH(he) HEK_HASH(HeKEY_hek(he))
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186#define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \
187 SvPV(HeKEY_sv(he),lp) : \
188 (((lp = HeKLEN(he)) >= 0) ? \
189 HeKEY(he) : Nullch))
190
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191#define HeSVKEY(he) ((HeKEY(he) && \
192 HeKLEN(he) == HEf_SVKEY) ? \
193 HeKEY_sv(he) : Nullsv)
194
195#define HeSVKEY_force(he) (HeKEY(he) ? \
196 ((HeKLEN(he) == HEf_SVKEY) ? \
197 HeKEY_sv(he) : \
79cb57f6 198 sv_2mortal(newSVpvn(HeKEY(he), \
bbce6d69 199 HeKLEN(he)))) : \
3280af22 200 &PL_sv_undef)
1e422769 201#define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv))
bbce6d69 202
ff68c719 203#define Nullhek Null(HEK*)
71be2cbc 204#define HEK_BASESIZE STRUCT_OFFSET(HEK, hek_key[0])
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205#define HEK_HASH(hek) (hek)->hek_hash
206#define HEK_LEN(hek) (hek)->hek_len
207#define HEK_KEY(hek) (hek)->hek_key
da58a35d 208#define HEK_UTF8(hek) (*(HEK_KEY(hek)+HEK_LEN(hek)))
d18c6117 209
5cbe4eec 210/* calculate HV array allocation */
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211#if defined(STRANGE_MALLOC) || defined(MYMALLOC)
212# define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
213#else
214# define MALLOC_OVERHEAD 16
215# define PERL_HV_ARRAY_ALLOC_BYTES(size) \
216 (((size) < 64) \
217 ? (size) * sizeof(HE*) \
218 : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
219#endif
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220
221/* available as a function in hv.c */
222#define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
223#define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash)