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 | **************************************************************************/
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21 |
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22 | #include "sysfuncs.h"
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23 |
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24 | #include "huffman.h"
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25 | #include "local_strings.h"
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26 | #include "memlib.h"
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27 | #include "messages.h"
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28 |
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29 | #include "mg.h"
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30 | #include "hash.h"
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31 | #include "text.h"
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32 | #include "comp_dict.h"
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33 | #include "locallib.h"
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34 | #include "mg_files.h"
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35 |
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36 | compression_dict_header cdh;
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37 | compressed_text_header cth;
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38 | comp_frags_header cfh[2];
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39 |
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40 | dict_hash_table *ht[2];
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41 |
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42 | huff_data char_huff[2];
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43 | huff_data lens_huff[2];
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44 | u_long *char_codes[2], *lens_codes[2];
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45 | u_long Words_disk = 0;
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46 | u_long Chars_disk = 0;
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47 |
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48 |
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49 | static dict_hash_table *
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50 | ReadInWords (FILE * dict, comp_frags_header * cfh,
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51 | int esc)
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52 | {
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53 | int i;
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54 | u_char *allwords, *prev = NULL;
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55 | dict_hash_table *ht;
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56 | u_char **words;
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57 | u_long ht_size;
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58 |
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59 | ht_size = prime (cfh->hd.num_codes * HASH_RATIO);
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60 | if (!(ht = (dict_hash_table *) Xmalloc (sizeof (dict_hash_table) +
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61 | (ht_size - 1) * sizeof (ht->table[0]))))
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62 | {
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63 | Message ("no memory for hash_table\n");
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64 | return NULL;
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65 | }
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66 |
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67 | ht->size = ht_size;
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68 | ht->hd = &cfh->hd;
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69 |
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70 | if (!(ht->codes = Generate_Huffman_Codes (&cfh->hd, NULL)))
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71 | {
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72 | Message ("no memory for huffman codes\n");
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73 | return NULL;
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74 | }
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75 |
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76 | if (!(ht->words = (u_char **) Xmalloc (sizeof (u_char *) * cfh->hd.num_codes)))
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77 | {
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78 | Message ("no memory for word pointers\n");
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79 | return NULL;
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80 | }
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81 | words = ht->words;
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82 |
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83 | memset (ht->table, '\0', ht_size * sizeof (ht->table[0]));
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84 |
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85 | if (!(allwords = (u_char *) Xmalloc (sizeof (u_char) * cfh->uncompressed_size)))
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86 | {
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87 | Message ("no memory for words\n");
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88 | return NULL;
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89 | }
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90 |
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91 | for (i = 0; i < cfh->hd.num_codes; i++, words++)
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92 | {
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93 | register int val, copy;
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94 | val = fgetc (dict);
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95 | copy = (val >> 4) & 0xf;
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96 | val &= 0xf;
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97 |
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98 | *words = allwords;
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99 |
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100 | memcpy (allwords + 1, prev + 1, copy);
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101 | fread (allwords + copy + 1, sizeof (u_char), val, dict);
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102 | *allwords = val + copy;
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103 |
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104 | Words_disk += val + 1;
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105 |
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106 | /* insert into the hash table */
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107 | if (i < cfh->hd.num_codes - esc)
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108 | {
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109 | register u_char **wptr;
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110 | register unsigned long tsize = ht->size;
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111 | register unsigned long hashval, step;
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112 |
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113 | HASH (hashval, step, allwords, tsize);
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114 |
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115 | wptr = ht->table[hashval];
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116 | for (; wptr;)
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117 | {
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118 | hashval += step;
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119 | if (hashval >= tsize)
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120 | hashval -= tsize;
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121 | wptr = ht->table[hashval];
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122 | }
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123 | ht->table[hashval] = words;
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124 | }
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125 | prev = allwords;
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126 | allwords += *allwords + 1;
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127 | }
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128 | return ht;
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129 | }
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130 |
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131 | inline int LoadWords(FILE *dict, int which)
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132 | {
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133 | if (Read_cfh (dict, &cfh[which], NULL, &Words_disk) == -1)
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134 | return 1;
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135 |
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136 | if (!(ht[which] = ReadInWords (dict, &cfh[which], 0)))
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137 | return 1;
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138 |
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139 | return 0;
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140 | }
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141 |
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142 | inline int LoadHuffmanCodes(FILE *dict, int which)
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143 | {
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144 | if (Read_Huffman_Data (dict, &char_huff[which], NULL,
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145 | &Chars_disk) == -1)
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146 | return 1;
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147 | if (!(char_codes[which] =
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148 | Generate_Huffman_Codes (&char_huff[which], NULL)))
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149 | return 2;
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150 | if (Read_Huffman_Data (dict, &lens_huff[which], NULL,
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151 | &Chars_disk) == -1)
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152 | return 3;
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153 | if (!(lens_codes[which] =
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154 | Generate_Huffman_Codes (&lens_huff[which], NULL)))
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155 | return 4;
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156 |
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157 | return 0;
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158 | }
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159 |
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160 | int
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161 | LoadCompressionDictionary (char *dict_file_name)
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162 | {
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163 | FILE *dict;
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164 | int which;
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165 | if (!(dict = open_named_file (dict_file_name, "rb", MAGIC_DICT, MG_MESSAGE))) /* [RPAP - Feb 97: WIN32 Port] */
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166 | return COMPERROR;
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167 |
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168 | Words_disk = sizeof (u_long);
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169 |
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170 | if (Read_cdh (dict, &cdh, NULL, &Words_disk) == -1)
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171 | goto error;
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172 |
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173 | for (which = 0; which < 2; which++)
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174 | switch (cdh.dict_type)
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175 | {
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176 | case MG_COMPLETE_DICTIONARY:
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177 | {
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178 | if (LoadWords(dict, which) != 0)
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179 | goto error;
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180 | }
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181 | break;
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182 | case MG_PARTIAL_DICTIONARY:
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183 | {
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184 | if (cdh.num_words[which])
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185 | {
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186 | if (LoadWords(dict, which) != 0)
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187 | goto error;
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188 | }
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189 | else
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190 | ht[which] = NULL;
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191 | if (LoadHuffmanCodes(dict, which) != 0)
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192 | goto error;
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193 | }
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194 | break;
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195 | case MG_SEED_DICTIONARY:
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196 | {
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197 | if (cdh.num_words[which])
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198 | {
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199 | if (LoadWords(dict, which) != 0)
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200 | goto error;
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201 | }
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202 | else
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203 | ht[which] = NULL;
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204 | switch (cdh.novel_method)
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205 | {
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206 | case MG_NOVEL_HUFFMAN_CHARS:
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207 | if (LoadHuffmanCodes(dict, which) != 0)
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208 | goto error;
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209 | break;
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210 | case MG_NOVEL_DELTA:
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211 | break;
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212 | case MG_NOVEL_HYBRID:
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213 | break;
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214 | default:
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215 | FatalError (1, "Bad novel method");
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216 | }
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217 | }
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218 | break;
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219 | default:
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220 | FatalError (1, "Bad dictionary kind\n");
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221 | }
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222 |
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223 | return (COMPALLOK);
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224 |
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225 |
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226 | error:
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227 | fclose (dict);
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228 | return (COMPERROR);
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229 | }
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