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1 /*
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2 * Copyright 1998-2002 Sun Microsystems, Inc. All Rights Reserved.
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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4 *
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5 * This code is free software; you can redistribute it and/or modify it
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6 * under the terms of the GNU General Public License version 2 only, as
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7 * published by the Free Software Foundation.
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8 *
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9 * This code is distributed in the hope that it will be useful, but WITHOUT
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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12 * version 2 for more details (a copy is included in the LICENSE file that
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13 * accompanied this code).
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14 *
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15 * You should have received a copy of the GNU General Public License version
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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18 *
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19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 // Dictionaries - An Abstract Data Type
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26
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27 #include "adlc.hpp"
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28
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29 // #include "dict.hpp"
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30
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31
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32 //------------------------------data-----------------------------------------
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33 // String hash tables
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34 #define MAXID 20
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35 static char initflag = 0; // True after 1st initialization
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36 static char shft[MAXID] = {1,2,3,4,5,6,7,1,2,3,4,5,6,7,1,2,3,4,5,6};
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37 static short xsum[MAXID + 1];
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38
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39 //------------------------------bucket---------------------------------------
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40 class bucket {
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41 public:
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42 int _cnt, _max; // Size of bucket
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43 const void **_keyvals; // Array of keys and values
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44 };
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45
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46 //------------------------------Dict-----------------------------------------
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47 // The dictionary is kept has a hash table. The hash table is a even power
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48 // of two, for nice modulo operations. Each bucket in the hash table points
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49 // to a linear list of key-value pairs; each key & value is just a (void *).
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50 // The list starts with a count. A hash lookup finds the list head, then a
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51 // simple linear scan finds the key. If the table gets too full, it's
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52 // doubled in size; the total amount of EXTRA times all hash functions are
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53 // computed for the doubling is no more than the current size - thus the
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54 // doubling in size costs no more than a constant factor in speed.
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55 Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp), _arena(NULL) {
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56 init();
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57 }
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58
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59 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena) : _hash(inithash), _cmp(initcmp), _arena(arena) {
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60 init();
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61 }
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62
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63 void Dict::init() {
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64 int i;
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65
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66 // Precompute table of null character hashes
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67 if( !initflag ) { // Not initializated yet?
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68 xsum[0] = (1<<shft[0])+1; // Initialize
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69 for( i = 1; i < MAXID + 1; i++) {
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70 xsum[i] = (1<<shft[i])+1+xsum[i-1];
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71 }
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72 initflag = 1; // Never again
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73 }
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74
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75 _size = 16; // Size is a power of 2
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76 _cnt = 0; // Dictionary is empty
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77 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
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78 memset(_bin,0,sizeof(bucket)*_size);
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79 }
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80
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81 //------------------------------~Dict------------------------------------------
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82 // Delete an existing dictionary.
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83 Dict::~Dict() {
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84 }
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85
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86 //------------------------------Clear----------------------------------------
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87 // Zap to empty; ready for re-use
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88 void Dict::Clear() {
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89 _cnt = 0; // Empty contents
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90 for( int i=0; i<_size; i++ )
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91 _bin[i]._cnt = 0; // Empty buckets, but leave allocated
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92 // Leave _size & _bin alone, under the assumption that dictionary will
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93 // grow to this size again.
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94 }
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95
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96 //------------------------------doubhash---------------------------------------
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97 // Double hash table size. If can't do so, just suffer. If can, then run
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98 // thru old hash table, moving things to new table. Note that since hash
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99 // table doubled, exactly 1 new bit is exposed in the mask - so everything
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100 // in the old table ends up on 1 of two lists in the new table; a hi and a
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101 // lo list depending on the value of the bit.
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102 void Dict::doubhash(void) {
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103 int oldsize = _size;
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104 _size <<= 1; // Double in size
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105 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );
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106 memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );
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107 // Rehash things to spread into new table
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108 for( int i=0; i < oldsize; i++) { // For complete OLD table do
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109 bucket *b = &_bin[i]; // Handy shortcut for _bin[i]
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110 if( !b->_keyvals ) continue; // Skip empties fast
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111
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112 bucket *nb = &_bin[i+oldsize]; // New bucket shortcut
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113 int j = b->_max; // Trim new bucket to nearest power of 2
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114 while( j > b->_cnt ) j >>= 1; // above old bucket _cnt
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115 if( !j ) j = 1; // Handle zero-sized buckets
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116 nb->_max = j<<1;
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117 // Allocate worst case space for key-value pairs
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118 nb->_keyvals = (const void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );
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119 int nbcnt = 0;
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120
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121 for( j=0; j<b->_cnt; j++ ) { // Rehash all keys in this bucket
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122 const void *key = b->_keyvals[j+j];
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123 if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?
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124 nb->_keyvals[nbcnt+nbcnt] = key;
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125 nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];
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126 nb->_cnt = nbcnt = nbcnt+1;
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127 b->_cnt--; // Remove key/value from lo bucket
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128 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
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129 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
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130 j--; // Hash compacted element also
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131 }
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132 } // End of for all key-value pairs in bucket
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133 } // End of for all buckets
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134
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135
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136 }
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137
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138 //------------------------------Dict-----------------------------------------
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139 // Deep copy a dictionary.
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140 Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {
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141 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
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142 memcpy( _bin, d._bin, sizeof(bucket)*_size );
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143 for( int i=0; i<_size; i++ ) {
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144 if( !_bin[i]._keyvals ) continue;
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145 _bin[i]._keyvals=(const void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2);
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146 memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));
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147 }
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148 }
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149
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150 //------------------------------Dict-----------------------------------------
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151 // Deep copy a dictionary.
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152 Dict &Dict::operator =( const Dict &d ) {
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153 if( _size < d._size ) { // If must have more buckets
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154 _arena = d._arena;
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155 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );
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156 memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
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157 _size = d._size;
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158 }
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159 for( int i=0; i<_size; i++ ) // All buckets are empty
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160 _bin[i]._cnt = 0; // But leave bucket allocations alone
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161 _cnt = d._cnt;
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162 *(Hash*)(&_hash) = d._hash;
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163 *(CmpKey*)(&_cmp) = d._cmp;
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164 for(int k=0; k<_size; k++ ) {
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165 bucket *b = &d._bin[k]; // Shortcut to source bucket
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166 for( int j=0; j<b->_cnt; j++ )
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167 Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );
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168 }
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169 return *this;
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170 }
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171
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172 //------------------------------Insert---------------------------------------
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173 // Insert or replace a key/value pair in the given dictionary. If the
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174 // dictionary is too full, it's size is doubled. The prior value being
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175 // replaced is returned (NULL if this is a 1st insertion of that key). If
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176 // an old value is found, it's swapped with the prior key-value pair on the
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177 // list. This moves a commonly searched-for value towards the list head.
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178 const void *Dict::Insert(const void *key, const void *val) {
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179 int hash = _hash( key ); // Get hash key
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180 int i = hash & (_size-1); // Get hash key, corrected for size
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181 bucket *b = &_bin[i]; // Handy shortcut
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182 for( int j=0; j<b->_cnt; j++ )
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183 if( !_cmp(key,b->_keyvals[j+j]) ) {
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184 const void *prior = b->_keyvals[j+j+1];
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185 b->_keyvals[j+j ] = key; // Insert current key-value
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186 b->_keyvals[j+j+1] = val;
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187 return prior; // Return prior
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188 }
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189
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190 if( ++_cnt > _size ) { // Hash table is full
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191 doubhash(); // Grow whole table if too full
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192 i = hash & (_size-1); // Rehash
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193 b = &_bin[i]; // Handy shortcut
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194 }
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195 if( b->_cnt == b->_max ) { // Must grow bucket?
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196 if( !b->_keyvals ) {
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197 b->_max = 2; // Initial bucket size
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198 b->_keyvals = (const void**)_arena->Amalloc_4( sizeof(void *)*b->_max*2 );
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199 } else {
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200 b->_keyvals = (const void**)_arena->Arealloc( b->_keyvals, sizeof(void *)*b->_max*2, sizeof(void *)*b->_max*4 );
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201 b->_max <<= 1; // Double bucket
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202 }
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203 }
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204 b->_keyvals[b->_cnt+b->_cnt ] = key;
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205 b->_keyvals[b->_cnt+b->_cnt+1] = val;
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206 b->_cnt++;
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207 return NULL; // Nothing found prior
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208 }
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209
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210 //------------------------------Delete---------------------------------------
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211 // Find & remove a value from dictionary. Return old value.
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212 const void *Dict::Delete(void *key) {
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213 int i = _hash( key ) & (_size-1); // Get hash key, corrected for size
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214 bucket *b = &_bin[i]; // Handy shortcut
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215 for( int j=0; j<b->_cnt; j++ )
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216 if( !_cmp(key,b->_keyvals[j+j]) ) {
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217 const void *prior = b->_keyvals[j+j+1];
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218 b->_cnt--; // Remove key/value from lo bucket
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219 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
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220 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
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221 _cnt--; // One less thing in table
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222 return prior;
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223 }
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224 return NULL;
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225 }
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226
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227 //------------------------------FindDict-------------------------------------
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228 // Find a key-value pair in the given dictionary. If not found, return NULL.
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229 // If found, move key-value pair towards head of list.
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230 const void *Dict::operator [](const void *key) const {
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231 int i = _hash( key ) & (_size-1); // Get hash key, corrected for size
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232 bucket *b = &_bin[i]; // Handy shortcut
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233 for( int j=0; j<b->_cnt; j++ )
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234 if( !_cmp(key,b->_keyvals[j+j]) )
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235 return b->_keyvals[j+j+1];
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236 return NULL;
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237 }
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238
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239 //------------------------------CmpDict--------------------------------------
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240 // CmpDict compares two dictionaries; they must have the same keys (their
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241 // keys must match using CmpKey) and they must have the same values (pointer
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242 // comparison). If so 1 is returned, if not 0 is returned.
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243 int Dict::operator ==(const Dict &d2) const {
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244 if( _cnt != d2._cnt ) return 0;
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245 if( _hash != d2._hash ) return 0;
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246 if( _cmp != d2._cmp ) return 0;
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247 for( int i=0; i < _size; i++) { // For complete hash table do
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248 bucket *b = &_bin[i]; // Handy shortcut
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249 if( b->_cnt != d2._bin[i]._cnt ) return 0;
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250 if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )
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251 return 0; // Key-value pairs must match
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252 }
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253 return 1; // All match, is OK
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254 }
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255
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256
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257 //------------------------------print----------------------------------------
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258 static void printvoid(const void* x) { printf("%p", x); }
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259 void Dict::print() {
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260 print(printvoid, printvoid);
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261 }
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262 void Dict::print(PrintKeyOrValue print_key, PrintKeyOrValue print_value) {
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263 for( int i=0; i < _size; i++) { // For complete hash table do
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264 bucket *b = &_bin[i]; // Handy shortcut
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265 for( int j=0; j<b->_cnt; j++ ) {
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266 print_key( b->_keyvals[j+j ]);
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267 printf(" -> ");
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268 print_value(b->_keyvals[j+j+1]);
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269 printf("\n");
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270 }
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271 }
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272 }
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273
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274 //------------------------------Hashing Functions----------------------------
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275 // Convert string to hash key. This algorithm implements a universal hash
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276 // function with the multipliers frozen (ok, so it's not universal). The
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277 // multipliers (and allowable characters) are all odd, so the resultant sum
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278 // is odd - guarenteed not divisible by any power of two, so the hash tables
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279 // can be any power of two with good results. Also, I choose multipliers
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280 // that have only 2 bits set (the low is always set to be odd) so
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281 // multiplication requires only shifts and adds. Characters are required to
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282 // be in the range 0-127 (I double & add 1 to force oddness). Keys are
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283 // limited to MAXID characters in length. Experimental evidence on 150K of
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284 // C text shows excellent spreading of values for any size hash table.
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285 int hashstr(const void *t) {
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286 register char c, k = 0;
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287 register int sum = 0;
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288 register const char *s = (const char *)t;
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289
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290 while( ((c = s[k]) != '\0') && (k < MAXID-1) ) { // Get characters till nul
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291 c = (c<<1)+1; // Characters are always odd!
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292 sum += c + (c<<shft[k++]); // Universal hash function
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293 }
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294 assert( k < (MAXID + 1), "Exceeded maximum name length");
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295 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size
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296 }
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297
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298 //------------------------------hashptr--------------------------------------
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299 // Slimey cheap hash function; no guarenteed performance. Better than the
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300 // default for pointers, especially on MS-DOS machines.
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301 int hashptr(const void *key) {
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302 #ifdef __TURBOC__
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303 return (int)((intptr_t)key >> 16);
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304 #else // __TURBOC__
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305 return (int)((intptr_t)key >> 2);
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306 #endif
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307 }
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308
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309 // Slimey cheap hash function; no guarenteed performance.
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310 int hashkey(const void *key) {
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311 return (int)((intptr_t)key);
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312 }
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313
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314 //------------------------------Key Comparator Functions---------------------
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315 int cmpstr(const void *k1, const void *k2) {
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316 return strcmp((const char *)k1,(const char *)k2);
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317 }
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318
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319 // Slimey cheap key comparator.
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320 int cmpkey(const void *key1, const void *key2) {
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321 return (int)((intptr_t)key1 - (intptr_t)key2);
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322 }
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323
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324 //=============================================================================
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325 //------------------------------reset------------------------------------------
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326 // Create an iterator and initialize the first variables.
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327 void DictI::reset( const Dict *dict ) {
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328 _d = dict; // The dictionary
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329 _i = (int)-1; // Before the first bin
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330 _j = 0; // Nothing left in the current bin
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331 ++(*this); // Step to first real value
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332 }
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333
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334 //------------------------------next-------------------------------------------
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335 // Find the next key-value pair in the dictionary, or return a NULL key and
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336 // value.
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337 void DictI::operator ++(void) {
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338 if( _j-- ) { // Still working in current bin?
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339 _key = _d->_bin[_i]._keyvals[_j+_j];
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340 _value = _d->_bin[_i]._keyvals[_j+_j+1];
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341 return;
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342 }
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343
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344 while( ++_i < _d->_size ) { // Else scan for non-zero bucket
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345 _j = _d->_bin[_i]._cnt;
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346 if( !_j ) continue;
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347 _j--;
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348 _key = _d->_bin[_i]._keyvals[_j+_j];
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349 _value = _d->_bin[_i]._keyvals[_j+_j+1];
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350 return;
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351 }
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352 _key = _value = NULL;
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353 }
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