1 | /**************************************************************************
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2 | *
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3 | * comp_dict.cpp -- Functions for loading the compression dictionary
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4 | * Copyright (C) 1994 Neil Sharman
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5 | *
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6 | * This program is free software; you can redistribute it and/or modify
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7 | * it under the terms of the GNU General Public License as published by
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8 | * the Free Software Foundation; either version 2 of the License, or
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9 | * (at your option) any later version.
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10 | *
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11 | * This program is distributed in the hope that it will be useful,
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 | * GNU General Public License for more details.
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15 | *
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16 | * You should have received a copy of the GNU General Public License
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17 | * along with this program; if not, write to the Free Software
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18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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19 | *
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20 | * $Id: comp_dict.cpp 856 2000-01-14 02:26:25Z sjboddie $
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21 | *
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22 | **************************************************************************/
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23 |
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24 | #include "sysfuncs.h"
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25 |
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26 | #include "huffman.h"
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27 | #include "local_strings.h"
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28 | #include "memlib.h"
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29 | #include "messages.h"
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30 |
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31 | #include "mg.h"
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32 | #include "hash.h"
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33 | #include "text.h"
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34 | #include "comp_dict.h"
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35 | #include "locallib.h"
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36 | #include "mg_files.h"
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37 |
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38 | /*
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39 | $Log$
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40 | Revision 1.1 2000/01/14 02:26:04 sjboddie
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41 | Rodgers new C++ mg
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42 |
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43 | Revision 1.1 1999/10/11 02:57:10 cs025
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44 | Base install of MG-PP
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45 |
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46 | Revision 1.1 1999/08/10 21:17:48 sjboddie
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47 | renamed mg-1.3d directory mg
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48 |
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49 | Revision 1.1 1998/11/17 09:34:34 rjmcnab
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50 | *** empty log message ***
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51 |
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52 | * Revision 1.3 1994/10/20 03:56:41 tes
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53 | * I have rewritten the boolean query optimiser and abstracted out the
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54 | * components of the boolean query.
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55 | *
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56 | * Revision 1.2 1994/09/20 04:41:24 tes
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57 | * For version 1.1
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58 | *
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59 | */
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60 |
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61 |
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62 | compression_dict_header cdh;
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63 | compressed_text_header cth;
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64 | comp_frags_header cfh[2];
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65 |
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66 | dict_hash_table *ht[2];
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67 |
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68 | huff_data char_huff[2];
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69 | huff_data lens_huff[2];
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70 | u_long *char_codes[2], *lens_codes[2];
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71 | u_long Words_disk = 0;
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72 | u_long Chars_disk = 0;
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73 |
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74 |
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75 | static dict_hash_table *
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76 | ReadInWords (FILE * dict, comp_frags_header * cfh,
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77 | int esc)
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78 | {
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79 | int i;
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80 | u_char *allwords, *prev = NULL;
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81 | dict_hash_table *ht;
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82 | u_char **words;
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83 | u_long ht_size;
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84 |
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85 | ht_size = prime (cfh->hd.num_codes * HASH_RATIO);
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86 | if (!(ht = (dict_hash_table *) Xmalloc (sizeof (dict_hash_table) +
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87 | (ht_size - 1) * sizeof (ht->table[0]))))
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88 | {
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89 | Message ("no memory for hash_table\n");
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90 | return NULL;
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91 | }
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92 |
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93 | ht->size = ht_size;
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94 | ht->hd = &cfh->hd;
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95 |
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96 | if (!(ht->codes = Generate_Huffman_Codes (&cfh->hd, NULL)))
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97 | {
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98 | Message ("no memory for huffman codes\n");
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99 | return NULL;
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100 | }
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101 |
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102 | if (!(ht->words = (u_char **) Xmalloc (sizeof (u_char *) * cfh->hd.num_codes)))
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103 | {
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104 | Message ("no memory for word pointers\n");
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105 | return NULL;
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106 | }
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107 | words = ht->words;
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108 |
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109 | bzero ((char *) ht->table, ht_size * sizeof (ht->table[0]));
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110 |
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111 | if (!(allwords = (u_char *) Xmalloc (sizeof (u_char) * cfh->uncompressed_size)))
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112 | {
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113 | Message ("no memory for words\n");
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114 | return NULL;
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115 | }
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116 |
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117 | for (i = 0; i < cfh->hd.num_codes; i++, words++)
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118 | {
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119 | register int val, copy;
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120 | val = fgetc (dict);
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121 | copy = (val >> 4) & 0xf;
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122 | val &= 0xf;
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123 |
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124 | *words = allwords;
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125 |
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126 | memcpy (allwords + 1, prev + 1, copy);
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127 | fread (allwords + copy + 1, sizeof (u_char), val, dict);
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128 | *allwords = val + copy;
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129 |
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130 | Words_disk += val + 1;
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131 |
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132 | /* insert into the hash table */
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133 | if (i < cfh->hd.num_codes - esc)
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134 | {
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135 | register u_char **wptr;
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136 | register unsigned long tsize = ht->size;
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137 | register unsigned long hashval, step;
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138 |
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139 | HASH (hashval, step, allwords, tsize);
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140 |
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141 | wptr = ht->table[hashval];
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142 | for (; wptr;)
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143 | {
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144 | hashval += step;
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145 | if (hashval >= tsize)
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146 | hashval -= tsize;
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147 | wptr = ht->table[hashval];
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148 | }
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149 | ht->table[hashval] = words;
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150 | }
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151 | prev = allwords;
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152 | allwords += *allwords + 1;
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153 | }
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154 | return ht;
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155 | }
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156 |
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157 | inline int LoadWords(FILE *dict, int which)
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158 | {
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159 | if (Read_cfh (dict, &cfh[which], NULL, &Words_disk) == -1)
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160 | return 1;
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161 |
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162 | if (!(ht[which] = ReadInWords (dict, &cfh[which], 0)))
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163 | return 1;
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164 |
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165 | return 0;
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166 | }
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167 |
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168 | inline int LoadHuffmanCodes(FILE *dict, int which)
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169 | {
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170 | if (Read_Huffman_Data (dict, &char_huff[which], NULL,
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171 | &Chars_disk) == -1)
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172 | return 1;
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173 | if (!(char_codes[which] =
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174 | Generate_Huffman_Codes (&char_huff[which], NULL)))
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175 | return 2;
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176 | if (Read_Huffman_Data (dict, &lens_huff[which], NULL,
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177 | &Chars_disk) == -1)
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178 | return 3;
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179 | if (!(lens_codes[which] =
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180 | Generate_Huffman_Codes (&lens_huff[which], NULL)))
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181 | return 4;
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182 |
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183 | return 0;
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184 | }
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185 |
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186 | int
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187 | LoadCompressionDictionary (char *dict_file_name)
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188 | {
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189 | FILE *dict;
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190 | int which;
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191 | if (!(dict = open_named_file (dict_file_name, "rb", MAGIC_DICT, MG_MESSAGE))) /* [RPAP - Feb 97: WIN32 Port] */
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192 | return COMPERROR;
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193 |
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194 | Words_disk = sizeof (u_long);
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195 |
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196 | if (Read_cdh (dict, &cdh, NULL, &Words_disk) == -1)
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197 | goto error;
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198 |
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199 | for (which = 0; which < 2; which++)
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200 | switch (cdh.dict_type)
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201 | {
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202 | case MG_COMPLETE_DICTIONARY:
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203 | {
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204 | if (LoadWords(dict, which) != 0)
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205 | goto error;
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206 | }
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207 | break;
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208 | case MG_PARTIAL_DICTIONARY:
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209 | {
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210 | if (cdh.num_words[which])
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211 | {
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212 | if (LoadWords(dict, which) != 0)
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213 | goto error;
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214 | }
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215 | else
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216 | ht[which] = NULL;
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217 | if (LoadHuffmanCodes(dict, which) != 0)
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218 | goto error;
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219 | }
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220 | break;
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221 | case MG_SEED_DICTIONARY:
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222 | {
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223 | if (cdh.num_words[which])
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224 | {
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225 | if (LoadWords(dict, which) != 0)
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226 | goto error;
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227 | }
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228 | else
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229 | ht[which] = NULL;
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230 | switch (cdh.novel_method)
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231 | {
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232 | case MG_NOVEL_HUFFMAN_CHARS:
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233 | if (LoadHuffmanCodes(dict, which) != 0)
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234 | goto error;
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235 | break;
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236 | case MG_NOVEL_DELTA:
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237 | break;
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238 | case MG_NOVEL_HYBRID:
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239 | break;
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240 | default:
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241 | FatalError (1, "Bad novel method");
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242 | }
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243 | }
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244 | break;
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245 | default:
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246 | FatalError (1, "Bad dictionary kind\n");
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247 | }
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248 |
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249 | return (COMPALLOK);
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250 |
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251 |
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252 | error:
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253 | fclose (dict);
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254 | return (COMPERROR);
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255 | }
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