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