1 | /* hv.h |
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2 | * |
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3 | * Copyright (C) 1991, 1992, 1993, 1996, 1997, 1998, 1999, |
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4 | * 2000, 2001, 2002, by Larry Wall and others |
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5 | * |
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6 | * You may distribute under the terms of either the GNU General Public |
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7 | * License or the Artistic License, as specified in the README file. |
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8 | * |
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9 | */ |
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10 | |
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11 | /* typedefs to eliminate some typing */ |
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12 | typedef struct he HE; |
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13 | typedef struct hek HEK; |
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14 | |
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15 | /* entry in hash value chain */ |
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16 | struct he { |
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17 | HE *hent_next; /* next entry in chain */ |
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18 | HEK *hent_hek; /* hash key */ |
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19 | SV *hent_val; /* scalar value that was hashed */ |
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20 | }; |
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21 | |
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22 | /* hash key -- defined separately for use as shared pointer */ |
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23 | struct hek { |
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24 | U32 hek_hash; /* hash of key */ |
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25 | I32 hek_len; /* length of hash key */ |
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26 | char hek_key[1]; /* variable-length hash key */ |
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27 | /* the hash-key is \0-terminated */ |
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28 | /* after the \0 there is a byte for flags, such as whether the key |
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29 | is UTF-8 */ |
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30 | }; |
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31 | |
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32 | /* hash structure: */ |
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33 | /* This structure must match the beginning of struct xpvmg in sv.h. */ |
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34 | struct xpvhv { |
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35 | char * xhv_array; /* pointer to malloced string */ |
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36 | STRLEN xhv_fill; /* how full xhv_array currently is */ |
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37 | STRLEN xhv_max; /* subscript of last element of xhv_array */ |
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38 | IV xhv_keys; /* how many elements in the array */ |
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39 | NV xnv_nv; /* numeric value, if any */ |
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40 | #define xhv_placeholders xnv_nv |
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41 | MAGIC* xmg_magic; /* magic for scalar array */ |
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42 | HV* xmg_stash; /* class package */ |
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43 | |
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44 | I32 xhv_riter; /* current root of iterator */ |
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45 | HE *xhv_eiter; /* current entry of iterator */ |
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46 | PMOP *xhv_pmroot; /* list of pm's for this package */ |
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47 | char *xhv_name; /* name, if a symbol table */ |
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48 | }; |
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49 | |
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50 | /* hash a key */ |
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51 | /* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins |
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52 | * from requirements by Colin Plumb. |
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53 | * (http://burtleburtle.net/bob/hash/doobs.html) */ |
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54 | /* The use of a temporary pointer and the casting games |
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55 | * is needed to serve the dual purposes of |
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56 | * (a) the hashed data being interpreted as "unsigned char" (new since 5.8, |
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57 | * a "char" can be either signed or signed, depending on the compiler) |
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58 | * (b) catering for old code that uses a "char" |
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59 | * |
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60 | * The "hash seed" feature was added in Perl 5.8.1 to perturb the results |
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61 | * to avoid "algorithmic complexity attacks". |
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62 | * |
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63 | * If USE_HASH_SEED is defined, hash randomisation is done by default |
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64 | * If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done |
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65 | * only if the environment variable PERL_HASH_SEED is set. |
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66 | * For maximal control, one can define PERL_HASH_SEED. |
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67 | * (see also erl.c:perl_parse()). |
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68 | */ |
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69 | #ifndef PERL_HASH_SEED |
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70 | # if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT) |
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71 | # define PERL_HASH_SEED PL_hash_seed |
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72 | # else |
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73 | # define PERL_HASH_SEED 0 |
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74 | # endif |
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75 | #endif |
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76 | #define PERL_HASH(hash,str,len) \ |
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77 | STMT_START { \ |
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78 | register const char *s_PeRlHaSh_tmp = str; \ |
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79 | register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \ |
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80 | register I32 i_PeRlHaSh = len; \ |
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81 | register U32 hash_PeRlHaSh = PERL_HASH_SEED; \ |
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82 | while (i_PeRlHaSh--) { \ |
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83 | hash_PeRlHaSh += *s_PeRlHaSh++; \ |
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84 | hash_PeRlHaSh += (hash_PeRlHaSh << 10); \ |
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85 | hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \ |
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86 | } \ |
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87 | hash_PeRlHaSh += (hash_PeRlHaSh << 3); \ |
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88 | hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \ |
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89 | (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \ |
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90 | } STMT_END |
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91 | |
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92 | /* Only hv.c and mod_perl should be doing this. */ |
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93 | #ifdef PERL_HASH_INTERNAL_ACCESS |
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94 | #define PERL_HASH_INTERNAL(hash,str,len) \ |
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95 | STMT_START { \ |
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96 | register const char *s_PeRlHaSh_tmp = str; \ |
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97 | register const unsigned char *s_PeRlHaSh = (const unsigned char *)s_PeRlHaSh_tmp; \ |
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98 | register I32 i_PeRlHaSh = len; \ |
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99 | register U32 hash_PeRlHaSh = PL_rehash_seed; \ |
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100 | while (i_PeRlHaSh--) { \ |
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101 | hash_PeRlHaSh += *s_PeRlHaSh++; \ |
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102 | hash_PeRlHaSh += (hash_PeRlHaSh << 10); \ |
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103 | hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \ |
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104 | } \ |
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105 | hash_PeRlHaSh += (hash_PeRlHaSh << 3); \ |
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106 | hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \ |
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107 | (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \ |
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108 | } STMT_END |
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109 | #endif |
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110 | |
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111 | /* |
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112 | =head1 Hash Manipulation Functions |
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113 | |
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114 | =for apidoc AmU||HEf_SVKEY |
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115 | This flag, used in the length slot of hash entries and magic structures, |
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116 | specifies the structure contains an C<SV*> pointer where a C<char*> pointer |
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117 | is to be expected. (For information only--not to be used). |
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118 | |
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119 | =head1 Handy Values |
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120 | |
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121 | =for apidoc AmU||Nullhv |
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122 | Null HV pointer. |
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123 | |
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124 | =head1 Hash Manipulation Functions |
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125 | |
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126 | =for apidoc Am|char*|HvNAME|HV* stash |
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127 | Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>. |
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128 | |
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129 | =for apidoc Am|void*|HeKEY|HE* he |
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130 | Returns the actual pointer stored in the key slot of the hash entry. The |
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131 | pointer may be either C<char*> or C<SV*>, depending on the value of |
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132 | C<HeKLEN()>. Can be assigned to. The C<HePV()> or C<HeSVKEY()> macros are |
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133 | usually preferable for finding the value of a key. |
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134 | |
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135 | =for apidoc Am|STRLEN|HeKLEN|HE* he |
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136 | If this is negative, and amounts to C<HEf_SVKEY>, it indicates the entry |
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137 | holds an C<SV*> key. Otherwise, holds the actual length of the key. Can |
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138 | be assigned to. The C<HePV()> macro is usually preferable for finding key |
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139 | lengths. |
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140 | |
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141 | =for apidoc Am|SV*|HeVAL|HE* he |
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142 | Returns the value slot (type C<SV*>) stored in the hash entry. |
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143 | |
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144 | =for apidoc Am|U32|HeHASH|HE* he |
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145 | Returns the computed hash stored in the hash entry. |
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146 | |
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147 | =for apidoc Am|char*|HePV|HE* he|STRLEN len |
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148 | Returns the key slot of the hash entry as a C<char*> value, doing any |
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149 | necessary dereferencing of possibly C<SV*> keys. The length of the string |
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150 | is placed in C<len> (this is a macro, so do I<not> use C<&len>). If you do |
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151 | not care about what the length of the key is, you may use the global |
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152 | variable C<PL_na>, though this is rather less efficient than using a local |
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153 | variable. Remember though, that hash keys in perl are free to contain |
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154 | embedded nulls, so using C<strlen()> or similar is not a good way to find |
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155 | the length of hash keys. This is very similar to the C<SvPV()> macro |
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156 | described elsewhere in this document. |
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157 | |
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158 | =for apidoc Am|SV*|HeSVKEY|HE* he |
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159 | Returns the key as an C<SV*>, or C<Nullsv> if the hash entry does not |
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160 | contain an C<SV*> key. |
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161 | |
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162 | =for apidoc Am|SV*|HeSVKEY_force|HE* he |
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163 | Returns the key as an C<SV*>. Will create and return a temporary mortal |
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164 | C<SV*> if the hash entry contains only a C<char*> key. |
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165 | |
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166 | =for apidoc Am|SV*|HeSVKEY_set|HE* he|SV* sv |
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167 | Sets the key to a given C<SV*>, taking care to set the appropriate flags to |
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168 | indicate the presence of an C<SV*> key, and returns the same |
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169 | C<SV*>. |
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170 | |
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171 | =cut |
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172 | */ |
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173 | |
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174 | /* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */ |
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175 | #define HEf_SVKEY -2 /* hent_key is an SV* */ |
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176 | |
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177 | |
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178 | #define Nullhv Null(HV*) |
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179 | #define HvARRAY(hv) (*(HE***)&((XPVHV*) SvANY(hv))->xhv_array) |
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180 | #define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill |
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181 | #define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max |
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182 | #define HvRITER(hv) ((XPVHV*) SvANY(hv))->xhv_riter |
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183 | #define HvEITER(hv) ((XPVHV*) SvANY(hv))->xhv_eiter |
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184 | #define HvPMROOT(hv) ((XPVHV*) SvANY(hv))->xhv_pmroot |
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185 | #define HvNAME(hv) ((XPVHV*) SvANY(hv))->xhv_name |
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186 | |
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187 | /* the number of keys (including any placeholers) */ |
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188 | #define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys) |
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189 | |
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190 | /* The number of placeholders in the enumerated-keys hash */ |
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191 | #define XHvPLACEHOLDERS(xhv) ((xhv)->xhv_placeholders) |
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192 | |
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193 | /* the number of keys that exist() (i.e. excluding placeholders) */ |
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194 | #define XHvUSEDKEYS(xhv) (XHvTOTALKEYS(xhv) - (IV)XHvPLACEHOLDERS(xhv)) |
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195 | |
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196 | /* |
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197 | * HvKEYS gets the number of keys that actually exist(), and is provided |
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198 | * for backwards compatibility with old XS code. The core uses HvUSEDKEYS |
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199 | * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders) |
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200 | */ |
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201 | #define HvKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv)) |
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202 | #define HvUSEDKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv)) |
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203 | #define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv)) |
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204 | #define HvPLACEHOLDERS(hv) XHvPLACEHOLDERS((XPVHV*) SvANY(hv)) |
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205 | |
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206 | #define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS) |
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207 | #define HvSHAREKEYS_on(hv) (SvFLAGS(hv) |= SVphv_SHAREKEYS) |
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208 | #define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS) |
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209 | |
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210 | /* This is an optimisation flag. It won't be set if all hash keys have a 0 |
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211 | * flag. Currently the only flags relate to utf8. |
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212 | * Hence it won't be set if all keys are 8 bit only. It will be set if any key |
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213 | * is utf8 (including 8 bit keys that were entered as utf8, and need upgrading |
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214 | * when retrieved during iteration. It may still be set when there are no longer |
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215 | * any utf8 keys. |
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216 | * See HVhek_ENABLEHVKFLAGS for the trigger. |
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217 | */ |
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218 | #define HvHASKFLAGS(hv) (SvFLAGS(hv) & SVphv_HASKFLAGS) |
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219 | #define HvHASKFLAGS_on(hv) (SvFLAGS(hv) |= SVphv_HASKFLAGS) |
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220 | #define HvHASKFLAGS_off(hv) (SvFLAGS(hv) &= ~SVphv_HASKFLAGS) |
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221 | |
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222 | #define HvLAZYDEL(hv) (SvFLAGS(hv) & SVphv_LAZYDEL) |
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223 | #define HvLAZYDEL_on(hv) (SvFLAGS(hv) |= SVphv_LAZYDEL) |
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224 | #define HvLAZYDEL_off(hv) (SvFLAGS(hv) &= ~SVphv_LAZYDEL) |
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225 | |
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226 | #define HvREHASH(hv) (SvFLAGS(hv) & SVphv_REHASH) |
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227 | #define HvREHASH_on(hv) (SvFLAGS(hv) |= SVphv_REHASH) |
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228 | #define HvREHASH_off(hv) (SvFLAGS(hv) &= ~SVphv_REHASH) |
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229 | |
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230 | /* Maybe amagical: */ |
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231 | /* #define HV_AMAGICmb(hv) (SvFLAGS(hv) & (SVpgv_badAM | SVpgv_AM)) */ |
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232 | |
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233 | #define HV_AMAGIC(hv) (SvFLAGS(hv) & SVpgv_AM) |
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234 | #define HV_AMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_AM) |
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235 | #define HV_AMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_AM) |
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236 | |
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237 | /* |
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238 | #define HV_AMAGICbad(hv) (SvFLAGS(hv) & SVpgv_badAM) |
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239 | #define HV_badAMAGIC_on(hv) (SvFLAGS(hv) |= SVpgv_badAM) |
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240 | #define HV_badAMAGIC_off(hv) (SvFLAGS(hv) &= ~SVpgv_badAM) |
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241 | */ |
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242 | |
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243 | #define Nullhe Null(HE*) |
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244 | #define HeNEXT(he) (he)->hent_next |
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245 | #define HeKEY_hek(he) (he)->hent_hek |
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246 | #define HeKEY(he) HEK_KEY(HeKEY_hek(he)) |
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247 | #define HeKEY_sv(he) (*(SV**)HeKEY(he)) |
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248 | #define HeKLEN(he) HEK_LEN(HeKEY_hek(he)) |
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249 | #define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he)) |
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250 | #define HeKWASUTF8(he) HEK_WASUTF8(HeKEY_hek(he)) |
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251 | #define HeKREHASH(he) HEK_REHASH(HeKEY_hek(he)) |
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252 | #define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he)) |
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253 | #define HeKFLAGS(he) HEK_FLAGS(HeKEY_hek(he)) |
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254 | #define HeVAL(he) (he)->hent_val |
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255 | #define HeHASH(he) HEK_HASH(HeKEY_hek(he)) |
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256 | #define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \ |
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257 | SvPV(HeKEY_sv(he),lp) : \ |
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258 | (((lp = HeKLEN(he)) >= 0) ? \ |
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259 | HeKEY(he) : Nullch)) |
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260 | |
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261 | #define HeSVKEY(he) ((HeKEY(he) && \ |
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262 | HeKLEN(he) == HEf_SVKEY) ? \ |
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263 | HeKEY_sv(he) : Nullsv) |
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264 | |
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265 | #define HeSVKEY_force(he) (HeKEY(he) ? \ |
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266 | ((HeKLEN(he) == HEf_SVKEY) ? \ |
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267 | HeKEY_sv(he) : \ |
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268 | sv_2mortal(newSVpvn(HeKEY(he), \ |
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269 | HeKLEN(he)))) : \ |
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270 | &PL_sv_undef) |
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271 | #define HeSVKEY_set(he,sv) ((HeKLEN(he) = HEf_SVKEY), (HeKEY_sv(he) = sv)) |
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272 | |
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273 | #define Nullhek Null(HEK*) |
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274 | #define HEK_BASESIZE STRUCT_OFFSET(HEK, hek_key[0]) |
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275 | #define HEK_HASH(hek) (hek)->hek_hash |
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276 | #define HEK_LEN(hek) (hek)->hek_len |
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277 | #define HEK_KEY(hek) (hek)->hek_key |
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278 | #define HEK_FLAGS(hek) (*((unsigned char *)(HEK_KEY(hek))+HEK_LEN(hek)+1)) |
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279 | |
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280 | #define HVhek_UTF8 0x01 /* Key is utf8 encoded. */ |
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281 | #define HVhek_WASUTF8 0x02 /* Key is bytes here, but was supplied as utf8. */ |
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282 | #define HVhek_REHASH 0x04 /* This key is in an hv using a custom HASH . */ |
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283 | #define HVhek_FREEKEY 0x100 /* Internal flag to say key is malloc()ed. */ |
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284 | #define HVhek_PLACEHOLD 0x200 /* Internal flag to create placeholder. |
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285 | * (may change, but Storable is a core module) */ |
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286 | #define HVhek_MASK 0xFF |
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287 | |
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288 | /* Which flags enable HvHASKFLAGS? Somewhat a hack on a hack, as |
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289 | HVhek_REHASH is only needed because the rehash flag has to be duplicated |
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290 | into all keys as hv_iternext has no access to the hash flags. At this |
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291 | point Storable's tests get upset, because sometimes hashes are "keyed" |
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292 | and sometimes not, depending on the order of data insertion, and whether |
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293 | it triggered rehashing. So currently HVhek_REHAS is exempt. |
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294 | */ |
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295 | |
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296 | #define HVhek_ENABLEHVKFLAGS (HVhek_MASK - HVhek_REHASH) |
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297 | |
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298 | #define HEK_UTF8(hek) (HEK_FLAGS(hek) & HVhek_UTF8) |
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299 | #define HEK_UTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_UTF8) |
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300 | #define HEK_UTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_UTF8) |
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301 | #define HEK_WASUTF8(hek) (HEK_FLAGS(hek) & HVhek_WASUTF8) |
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302 | #define HEK_WASUTF8_on(hek) (HEK_FLAGS(hek) |= HVhek_WASUTF8) |
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303 | #define HEK_WASUTF8_off(hek) (HEK_FLAGS(hek) &= ~HVhek_WASUTF8) |
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304 | #define HEK_REHASH(hek) (HEK_FLAGS(hek) & HVhek_REHASH) |
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305 | #define HEK_REHASH_on(hek) (HEK_FLAGS(hek) |= HVhek_REHASH) |
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306 | |
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307 | /* calculate HV array allocation */ |
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308 | #if defined(STRANGE_MALLOC) || defined(MYMALLOC) |
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309 | # define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*)) |
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310 | #else |
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311 | # define MALLOC_OVERHEAD 16 |
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312 | # define PERL_HV_ARRAY_ALLOC_BYTES(size) \ |
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313 | (((size) < 64) \ |
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314 | ? (size) * sizeof(HE*) \ |
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315 | : (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD) |
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316 | #endif |
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317 | |
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318 | /* Flags for hv_iternext_flags. */ |
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319 | #define HV_ITERNEXT_WANTPLACEHOLDERS 0x01 /* Don't skip placeholders. */ |
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320 | |
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321 | /* available as a function in hv.c */ |
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322 | #define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash)) |
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323 | #define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash) |
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