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1 /*
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2 * Copyright 1997-2003 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 "incls/_precompiled.incl"
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28 #include "incls/_dict.cpp.incl"
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29
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30 // %%%%% includes not needed with AVM framework - Ungar
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31
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32 // #include "port.hpp"
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33 //IMPLEMENTATION
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34 // #include "dict.hpp"
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35
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36 #include <assert.h>
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37
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38 // The iostream is not needed and it gets confused for gcc by the
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39 // define of bool.
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40 //
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41 // #include <iostream.h>
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42
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43 //------------------------------data-----------------------------------------
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44 // String hash tables
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45 #define MAXID 20
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46 static byte initflag = 0; // True after 1st initialization
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47 static const 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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48 static short xsum[MAXID];
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49
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50 //------------------------------bucket---------------------------------------
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51 class bucket : public ResourceObj {
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52 public:
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53 uint _cnt, _max; // Size of bucket
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54 void **_keyvals; // Array of keys and values
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55 };
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56
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57 //------------------------------Dict-----------------------------------------
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58 // The dictionary is kept has a hash table. The hash table is a even power
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59 // of two, for nice modulo operations. Each bucket in the hash table points
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60 // to a linear list of key-value pairs; each key & value is just a (void *).
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61 // The list starts with a count. A hash lookup finds the list head, then a
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62 // simple linear scan finds the key. If the table gets too full, it's
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63 // doubled in size; the total amount of EXTRA times all hash functions are
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64 // computed for the doubling is no more than the current size - thus the
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65 // doubling in size costs no more than a constant factor in speed.
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66 Dict::Dict(CmpKey initcmp, Hash inithash) : _hash(inithash), _cmp(initcmp),
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67 _arena(Thread::current()->resource_area()) {
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68 int i;
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69
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70 // Precompute table of null character hashes
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71 if( !initflag ) { // Not initializated yet?
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72 xsum[0] = (1<<shft[0])+1; // Initialize
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73 for(i=1; i<MAXID; i++) {
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74 xsum[i] = (1<<shft[i])+1+xsum[i-1];
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75 }
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76 initflag = 1; // Never again
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77 }
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78
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79 _size = 16; // Size is a power of 2
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80 _cnt = 0; // Dictionary is empty
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81 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
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82 memset(_bin,0,sizeof(bucket)*_size);
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83 }
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84
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85 Dict::Dict(CmpKey initcmp, Hash inithash, Arena *arena, int size)
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86 : _hash(inithash), _cmp(initcmp), _arena(arena) {
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87 int i;
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88
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89 // Precompute table of null character hashes
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90 if( !initflag ) { // Not initializated yet?
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91 xsum[0] = (1<<shft[0])+1; // Initialize
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92 for(i=1; i<MAXID; i++) {
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93 xsum[i] = (1<<shft[i])+1+xsum[i-1];
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94 }
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95 initflag = 1; // Never again
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96 }
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97
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98 i=16;
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99 while( i < size ) i <<= 1;
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100 _size = i; // Size is a power of 2
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101 _cnt = 0; // Dictionary is empty
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102 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
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103 memset(_bin,0,sizeof(bucket)*_size);
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104 }
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105
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106 //------------------------------~Dict------------------------------------------
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107 // Delete an existing dictionary.
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108 Dict::~Dict() {
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109 /*
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110 tty->print("~Dict %d/%d: ",_cnt,_size);
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111 for( uint i=0; i < _size; i++) // For complete new table do
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112 tty->print("%d ",_bin[i]._cnt);
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113 tty->print("\n");*/
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114 /*for( uint i=0; i<_size; i++ ) {
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115 FREE_FAST( _bin[i]._keyvals );
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116 } */
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117 }
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118
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119 //------------------------------Clear----------------------------------------
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120 // Zap to empty; ready for re-use
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121 void Dict::Clear() {
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122 _cnt = 0; // Empty contents
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123 for( uint i=0; i<_size; i++ )
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124 _bin[i]._cnt = 0; // Empty buckets, but leave allocated
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125 // Leave _size & _bin alone, under the assumption that dictionary will
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126 // grow to this size again.
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127 }
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128
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129 //------------------------------doubhash---------------------------------------
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130 // Double hash table size. If can't do so, just suffer. If can, then run
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131 // thru old hash table, moving things to new table. Note that since hash
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132 // table doubled, exactly 1 new bit is exposed in the mask - so everything
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133 // in the old table ends up on 1 of two lists in the new table; a hi and a
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134 // lo list depending on the value of the bit.
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135 void Dict::doubhash(void) {
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136 uint oldsize = _size;
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137 _size <<= 1; // Double in size
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138 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*oldsize, sizeof(bucket)*_size );
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139 memset( &_bin[oldsize], 0, oldsize*sizeof(bucket) );
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140 // Rehash things to spread into new table
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141 for( uint i=0; i < oldsize; i++) { // For complete OLD table do
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142 bucket *b = &_bin[i]; // Handy shortcut for _bin[i]
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143 if( !b->_keyvals ) continue; // Skip empties fast
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144
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145 bucket *nb = &_bin[i+oldsize]; // New bucket shortcut
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146 uint j = b->_max; // Trim new bucket to nearest power of 2
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147 while( j > b->_cnt ) j >>= 1; // above old bucket _cnt
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148 if( !j ) j = 1; // Handle zero-sized buckets
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149 nb->_max = j<<1;
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150 // Allocate worst case space for key-value pairs
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151 nb->_keyvals = (void**)_arena->Amalloc_4( sizeof(void *)*nb->_max*2 );
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152 uint nbcnt = 0;
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153
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154 for( j=0; j<b->_cnt; j++ ) { // Rehash all keys in this bucket
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155 void *key = b->_keyvals[j+j];
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156 if( (_hash( key ) & (_size-1)) != i ) { // Moving to hi bucket?
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157 nb->_keyvals[nbcnt+nbcnt] = key;
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158 nb->_keyvals[nbcnt+nbcnt+1] = b->_keyvals[j+j+1];
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159 nb->_cnt = nbcnt = nbcnt+1;
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160 b->_cnt--; // Remove key/value from lo bucket
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161 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
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162 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
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163 j--; // Hash compacted element also
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164 }
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165 } // End of for all key-value pairs in bucket
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166 } // End of for all buckets
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167
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168
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169 }
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170
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171 //------------------------------Dict-----------------------------------------
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172 // Deep copy a dictionary.
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173 Dict::Dict( const Dict &d ) : _size(d._size), _cnt(d._cnt), _hash(d._hash),_cmp(d._cmp), _arena(d._arena) {
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174 _bin = (bucket*)_arena->Amalloc_4(sizeof(bucket)*_size);
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175 memcpy( _bin, d._bin, sizeof(bucket)*_size );
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176 for( uint i=0; i<_size; i++ ) {
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177 if( !_bin[i]._keyvals ) continue;
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178 _bin[i]._keyvals=(void**)_arena->Amalloc_4( sizeof(void *)*_bin[i]._max*2);
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179 memcpy( _bin[i]._keyvals, d._bin[i]._keyvals,_bin[i]._cnt*2*sizeof(void*));
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180 }
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181 }
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182
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183 //------------------------------Dict-----------------------------------------
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184 // Deep copy a dictionary.
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185 Dict &Dict::operator =( const Dict &d ) {
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186 if( _size < d._size ) { // If must have more buckets
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187 _arena = d._arena;
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188 _bin = (bucket*)_arena->Arealloc( _bin, sizeof(bucket)*_size, sizeof(bucket)*d._size );
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189 memset( &_bin[_size], 0, (d._size-_size)*sizeof(bucket) );
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190 _size = d._size;
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191 }
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192 uint i;
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193 for( i=0; i<_size; i++ ) // All buckets are empty
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194 _bin[i]._cnt = 0; // But leave bucket allocations alone
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195 _cnt = d._cnt;
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196 *(Hash*)(&_hash) = d._hash;
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197 *(CmpKey*)(&_cmp) = d._cmp;
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198 for( i=0; i<_size; i++ ) {
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199 bucket *b = &d._bin[i]; // Shortcut to source bucket
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200 for( uint j=0; j<b->_cnt; j++ )
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201 Insert( b->_keyvals[j+j], b->_keyvals[j+j+1] );
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202 }
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203 return *this;
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204 }
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205
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206 //------------------------------Insert----------------------------------------
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207 // Insert or replace a key/value pair in the given dictionary. If the
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208 // dictionary is too full, it's size is doubled. The prior value being
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209 // replaced is returned (NULL if this is a 1st insertion of that key). If
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210 // an old value is found, it's swapped with the prior key-value pair on the
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211 // list. This moves a commonly searched-for value towards the list head.
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212 void *Dict::Insert(void *key, void *val, bool replace) {
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213 uint hash = _hash( key ); // Get hash key
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214 uint i = hash & (_size-1); // Get hash key, corrected for size
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215 bucket *b = &_bin[i]; // Handy shortcut
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216 for( uint j=0; j<b->_cnt; j++ ) {
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217 if( !_cmp(key,b->_keyvals[j+j]) ) {
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218 if (!replace) {
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219 return b->_keyvals[j+j+1];
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220 } else {
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221 void *prior = b->_keyvals[j+j+1];
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222 b->_keyvals[j+j ] = key; // Insert current key-value
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223 b->_keyvals[j+j+1] = val;
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224 return prior; // Return prior
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225 }
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226 }
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227 }
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228 if( ++_cnt > _size ) { // Hash table is full
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229 doubhash(); // Grow whole table if too full
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230 i = hash & (_size-1); // Rehash
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231 b = &_bin[i]; // Handy shortcut
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232 }
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233 if( b->_cnt == b->_max ) { // Must grow bucket?
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234 if( !b->_keyvals ) {
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235 b->_max = 2; // Initial bucket size
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236 b->_keyvals = (void**)_arena->Amalloc_4(sizeof(void*) * b->_max * 2);
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237 } else {
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238 b->_keyvals = (void**)_arena->Arealloc(b->_keyvals, sizeof(void*) * b->_max * 2, sizeof(void*) * b->_max * 4);
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239 b->_max <<= 1; // Double bucket
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240 }
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241 }
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242 b->_keyvals[b->_cnt+b->_cnt ] = key;
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243 b->_keyvals[b->_cnt+b->_cnt+1] = val;
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244 b->_cnt++;
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245 return NULL; // Nothing found prior
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246 }
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247
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248 //------------------------------Delete---------------------------------------
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249 // Find & remove a value from dictionary. Return old value.
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250 void *Dict::Delete(void *key) {
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251 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size
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252 bucket *b = &_bin[i]; // Handy shortcut
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253 for( uint j=0; j<b->_cnt; j++ )
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254 if( !_cmp(key,b->_keyvals[j+j]) ) {
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255 void *prior = b->_keyvals[j+j+1];
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256 b->_cnt--; // Remove key/value from lo bucket
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257 b->_keyvals[j+j ] = b->_keyvals[b->_cnt+b->_cnt ];
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258 b->_keyvals[j+j+1] = b->_keyvals[b->_cnt+b->_cnt+1];
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259 _cnt--; // One less thing in table
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260 return prior;
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261 }
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262 return NULL;
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263 }
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264
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265 //------------------------------FindDict-------------------------------------
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266 // Find a key-value pair in the given dictionary. If not found, return NULL.
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267 // If found, move key-value pair towards head of list.
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268 void *Dict::operator [](const void *key) const {
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269 uint i = _hash( key ) & (_size-1); // Get hash key, corrected for size
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270 bucket *b = &_bin[i]; // Handy shortcut
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271 for( uint j=0; j<b->_cnt; j++ )
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272 if( !_cmp(key,b->_keyvals[j+j]) )
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273 return b->_keyvals[j+j+1];
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274 return NULL;
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275 }
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276
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277 //------------------------------CmpDict--------------------------------------
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278 // CmpDict compares two dictionaries; they must have the same keys (their
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279 // keys must match using CmpKey) and they must have the same values (pointer
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280 // comparison). If so 1 is returned, if not 0 is returned.
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281 int32 Dict::operator ==(const Dict &d2) const {
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282 if( _cnt != d2._cnt ) return 0;
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283 if( _hash != d2._hash ) return 0;
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284 if( _cmp != d2._cmp ) return 0;
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285 for( uint i=0; i < _size; i++) { // For complete hash table do
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286 bucket *b = &_bin[i]; // Handy shortcut
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287 if( b->_cnt != d2._bin[i]._cnt ) return 0;
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288 if( memcmp(b->_keyvals, d2._bin[i]._keyvals, b->_cnt*2*sizeof(void*) ) )
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289 return 0; // Key-value pairs must match
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290 }
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291 return 1; // All match, is OK
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292 }
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293
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294 //------------------------------print------------------------------------------
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295 // Handier print routine
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296 void Dict::print() {
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297 DictI i(this); // Moved definition in iterator here because of g++.
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298 tty->print("Dict@0x%lx[%d] = {", this, _cnt);
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299 for( ; i.test(); ++i ) {
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300 tty->print("(0x%lx,0x%lx),", i._key, i._value);
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301 }
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302 tty->print_cr("}");
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303 }
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304
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305 //------------------------------Hashing Functions----------------------------
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306 // Convert string to hash key. This algorithm implements a universal hash
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307 // function with the multipliers frozen (ok, so it's not universal). The
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308 // multipliers (and allowable characters) are all odd, so the resultant sum
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309 // is odd - guarenteed not divisible by any power of two, so the hash tables
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310 // can be any power of two with good results. Also, I choose multipliers
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311 // that have only 2 bits set (the low is always set to be odd) so
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312 // multiplication requires only shifts and adds. Characters are required to
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313 // be in the range 0-127 (I double & add 1 to force oddness). Keys are
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314 // limited to MAXID characters in length. Experimental evidence on 150K of
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315 // C text shows excellent spreading of values for any size hash table.
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316 int hashstr(const void *t) {
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317 register char c, k = 0;
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318 register int32 sum = 0;
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319 register const char *s = (const char *)t;
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320
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321 while( ((c = *s++) != '\0') && (k < MAXID-1) ) { // Get characters till null or MAXID-1
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322 c = (c<<1)+1; // Characters are always odd!
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323 sum += c + (c<<shft[k++]); // Universal hash function
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324 }
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325 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size
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326 }
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327
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328 //------------------------------hashptr--------------------------------------
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329 // Slimey cheap hash function; no guarenteed performance. Better than the
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330 // default for pointers, especially on MS-DOS machines.
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331 int hashptr(const void *key) {
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332 #ifdef __TURBOC__
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333 return ((intptr_t)key >> 16);
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334 #else // __TURBOC__
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335 return ((intptr_t)key >> 2);
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336 #endif
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337 }
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338
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339 // Slimey cheap hash function; no guarenteed performance.
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340 int hashkey(const void *key) {
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341 return (intptr_t)key;
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342 }
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343
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344 //------------------------------Key Comparator Functions---------------------
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345 int32 cmpstr(const void *k1, const void *k2) {
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346 return strcmp((const char *)k1,(const char *)k2);
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347 }
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348
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349 // Slimey cheap key comparator.
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350 int32 cmpkey(const void *key1, const void *key2) {
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351 return (int32)((intptr_t)key1 - (intptr_t)key2);
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352 }
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353
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354 //=============================================================================
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355 //------------------------------reset------------------------------------------
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356 // Create an iterator and initialize the first variables.
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357 void DictI::reset( const Dict *dict ) {
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358 _d = dict; // The dictionary
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359 _i = (uint)-1; // Before the first bin
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360 _j = 0; // Nothing left in the current bin
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361 ++(*this); // Step to first real value
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362 }
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363
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364 //------------------------------next-------------------------------------------
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365 // Find the next key-value pair in the dictionary, or return a NULL key and
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366 // value.
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367 void DictI::operator ++(void) {
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368 if( _j-- ) { // Still working in current bin?
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369 _key = _d->_bin[_i]._keyvals[_j+_j];
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370 _value = _d->_bin[_i]._keyvals[_j+_j+1];
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371 return;
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372 }
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373
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374 while( ++_i < _d->_size ) { // Else scan for non-zero bucket
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375 _j = _d->_bin[_i]._cnt;
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376 if( !_j ) continue;
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377 _j--;
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378 _key = _d->_bin[_i]._keyvals[_j+_j];
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379 _value = _d->_bin[_i]._keyvals[_j+_j+1];
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380 return;
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381 }
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382 _key = _value = NULL;
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383 }
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