1 /* |
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2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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3 * |
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4 * This code is free software; you can redistribute it and/or modify it |
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5 * under the terms of the GNU General Public License version 2 only, as |
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6 * published by the Free Software Foundation. Sun designates this |
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7 * particular file as subject to the "Classpath" exception as provided |
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8 * by Sun in the LICENSE file that accompanied this code. |
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9 * |
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10 * This code is distributed in the hope that it will be useful, but WITHOUT |
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11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 * version 2 for more details (a copy is included in the LICENSE file that |
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14 * accompanied this code). |
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15 * |
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16 * You should have received a copy of the GNU General Public License version |
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17 * 2 along with this work; if not, write to the Free Software Foundation, |
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18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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19 * |
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20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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21 * CA 95054 USA or visit www.sun.com if you need additional information or |
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22 * have any questions. |
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23 */ |
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24 |
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25 /* |
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26 * This file is available under and governed by the GNU General Public |
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27 * License version 2 only, as published by the Free Software Foundation. |
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28 * However, the following notice accompanied the original version of this |
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29 * file and, per its terms, should not be removed: |
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30 * |
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31 * infcodes.c -- process literals and length/distance pairs |
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32 * Copyright (C) 1995-1998 Mark Adler |
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33 * For conditions of distribution and use, see copyright notice in zlib.h |
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34 */ |
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35 |
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36 #include "zutil.h" |
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37 #include "inftrees.h" |
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38 #include "infblock.h" |
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39 #include "infcodes.h" |
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40 #include "infutil.h" |
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41 #include "inffast.h" |
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42 |
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43 /* simplify the use of the inflate_huft type with some defines */ |
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44 #define exop word.what.Exop |
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45 #define bits word.what.Bits |
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46 |
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47 typedef enum { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */ |
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48 START, /* x: set up for LEN */ |
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49 LEN, /* i: get length/literal/eob next */ |
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50 LENEXT, /* i: getting length extra (have base) */ |
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51 DIST, /* i: get distance next */ |
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52 DISTEXT, /* i: getting distance extra */ |
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53 COPY, /* o: copying bytes in window, waiting for space */ |
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54 LIT, /* o: got literal, waiting for output space */ |
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55 WASH, /* o: got eob, possibly still output waiting */ |
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56 END, /* x: got eob and all data flushed */ |
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57 BADCODE} /* x: got error */ |
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58 inflate_codes_mode; |
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59 |
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60 /* inflate codes private state */ |
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61 struct inflate_codes_state { |
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62 |
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63 /* mode */ |
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64 inflate_codes_mode mode; /* current inflate_codes mode */ |
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65 |
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66 /* mode dependent information */ |
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67 uInt len; |
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68 union { |
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69 struct { |
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70 inflate_huft *tree; /* pointer into tree */ |
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71 uInt need; /* bits needed */ |
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72 } code; /* if LEN or DIST, where in tree */ |
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73 uInt lit; /* if LIT, literal */ |
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74 struct { |
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75 uInt get; /* bits to get for extra */ |
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76 uInt dist; /* distance back to copy from */ |
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77 } copy; /* if EXT or COPY, where and how much */ |
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78 } sub; /* submode */ |
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79 |
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80 /* mode independent information */ |
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81 Byte lbits; /* ltree bits decoded per branch */ |
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82 Byte dbits; /* dtree bits decoder per branch */ |
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83 inflate_huft *ltree; /* literal/length/eob tree */ |
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84 inflate_huft *dtree; /* distance tree */ |
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85 |
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86 }; |
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87 |
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88 |
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89 inflate_codes_statef *inflate_codes_new(bl, bd, tl, td, z) |
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90 uInt bl, bd; |
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91 inflate_huft *tl; |
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92 inflate_huft *td; /* need separate declaration for Borland C++ */ |
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93 z_streamp z; |
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94 { |
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95 inflate_codes_statef *c; |
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96 |
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97 if ((c = (inflate_codes_statef *) |
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98 ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL) |
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99 { |
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100 c->mode = START; |
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101 c->lbits = (Byte)bl; |
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102 c->dbits = (Byte)bd; |
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103 c->ltree = tl; |
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104 c->dtree = td; |
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105 Tracev((stderr, "inflate: codes new\n")); |
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106 } |
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107 return c; |
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108 } |
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109 |
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110 |
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111 int inflate_codes(s, z, r) |
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112 inflate_blocks_statef *s; |
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113 z_streamp z; |
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114 int r; |
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115 { |
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116 uInt j; /* temporary storage */ |
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117 inflate_huft *t; /* temporary pointer */ |
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118 uInt e; /* extra bits or operation */ |
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119 uLong b; /* bit buffer */ |
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120 uInt k; /* bits in bit buffer */ |
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121 Bytef *p; /* input data pointer */ |
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122 uInt n; /* bytes available there */ |
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123 Bytef *q; /* output window write pointer */ |
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124 uInt m; /* bytes to end of window or read pointer */ |
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125 Bytef *f; /* pointer to copy strings from */ |
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126 inflate_codes_statef *c = s->sub.decode.codes; /* codes state */ |
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127 |
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128 /* copy input/output information to locals (UPDATE macro restores) */ |
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129 LOAD |
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130 |
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131 /* process input and output based on current state */ |
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132 while (1) switch (c->mode) |
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133 { /* waiting for "i:"=input, "o:"=output, "x:"=nothing */ |
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134 case START: /* x: set up for LEN */ |
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135 #ifndef SLOW |
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136 if (m >= 258 && n >= 10) |
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137 { |
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138 UPDATE |
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139 r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z); |
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140 LOAD |
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141 if (r != Z_OK) |
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142 { |
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143 c->mode = r == Z_STREAM_END ? WASH : BADCODE; |
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144 break; |
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145 } |
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146 } |
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147 #endif /* !SLOW */ |
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148 c->sub.code.need = c->lbits; |
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149 c->sub.code.tree = c->ltree; |
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150 c->mode = LEN; |
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151 case LEN: /* i: get length/literal/eob next */ |
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152 j = c->sub.code.need; |
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153 NEEDBITS(j) |
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154 t = c->sub.code.tree + ((uInt)b & inflate_mask[j]); |
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155 DUMPBITS(t->bits) |
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156 e = (uInt)(t->exop); |
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157 if (e == 0) /* literal */ |
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158 { |
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159 c->sub.lit = t->base; |
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160 Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ? |
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161 "inflate: literal '%c'\n" : |
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162 "inflate: literal 0x%02x\n", t->base)); |
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163 c->mode = LIT; |
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164 break; |
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165 } |
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166 if (e & 16) /* length */ |
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167 { |
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168 c->sub.copy.get = e & 15; |
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169 c->len = t->base; |
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170 c->mode = LENEXT; |
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171 break; |
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172 } |
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173 if ((e & 64) == 0) /* next table */ |
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174 { |
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175 c->sub.code.need = e; |
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176 c->sub.code.tree = t + t->base; |
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177 break; |
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178 } |
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179 if (e & 32) /* end of block */ |
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180 { |
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181 Tracevv((stderr, "inflate: end of block\n")); |
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182 c->mode = WASH; |
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183 break; |
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184 } |
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185 c->mode = BADCODE; /* invalid code */ |
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186 z->msg = (char*)"invalid literal/length code"; |
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187 r = Z_DATA_ERROR; |
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188 LEAVE |
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189 case LENEXT: /* i: getting length extra (have base) */ |
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190 j = c->sub.copy.get; |
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191 NEEDBITS(j) |
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192 c->len += (uInt)b & inflate_mask[j]; |
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193 DUMPBITS(j) |
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194 c->sub.code.need = c->dbits; |
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195 c->sub.code.tree = c->dtree; |
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196 Tracevv((stderr, "inflate: length %u\n", c->len)); |
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197 c->mode = DIST; |
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198 case DIST: /* i: get distance next */ |
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199 j = c->sub.code.need; |
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200 NEEDBITS(j) |
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201 t = c->sub.code.tree + ((uInt)b & inflate_mask[j]); |
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202 DUMPBITS(t->bits) |
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203 e = (uInt)(t->exop); |
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204 if (e & 16) /* distance */ |
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205 { |
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206 c->sub.copy.get = e & 15; |
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207 c->sub.copy.dist = t->base; |
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208 c->mode = DISTEXT; |
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209 break; |
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210 } |
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211 if ((e & 64) == 0) /* next table */ |
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212 { |
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213 c->sub.code.need = e; |
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214 c->sub.code.tree = t + t->base; |
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215 break; |
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216 } |
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217 c->mode = BADCODE; /* invalid code */ |
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218 z->msg = (char*)"invalid distance code"; |
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219 r = Z_DATA_ERROR; |
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220 LEAVE |
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221 case DISTEXT: /* i: getting distance extra */ |
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222 j = c->sub.copy.get; |
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223 NEEDBITS(j) |
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224 c->sub.copy.dist += (uInt)b & inflate_mask[j]; |
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225 DUMPBITS(j) |
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226 Tracevv((stderr, "inflate: distance %u\n", c->sub.copy.dist)); |
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227 c->mode = COPY; |
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228 case COPY: /* o: copying bytes in window, waiting for space */ |
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229 #ifndef __TURBOC__ /* Turbo C bug for following expression */ |
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230 f = (uInt)(q - s->window) < c->sub.copy.dist ? |
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231 s->end - (c->sub.copy.dist - (q - s->window)) : |
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232 q - c->sub.copy.dist; |
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233 #else |
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234 f = q - c->sub.copy.dist; |
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235 if ((uInt)(q - s->window) < c->sub.copy.dist) |
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236 f = s->end - (c->sub.copy.dist - (uInt)(q - s->window)); |
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237 #endif |
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238 while (c->len) |
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239 { |
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240 NEEDOUT |
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241 OUTBYTE(*f++) |
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242 if (f == s->end) |
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243 f = s->window; |
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244 c->len--; |
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245 } |
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246 c->mode = START; |
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247 break; |
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248 case LIT: /* o: got literal, waiting for output space */ |
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249 NEEDOUT |
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250 OUTBYTE(c->sub.lit) |
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251 c->mode = START; |
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252 break; |
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253 case WASH: /* o: got eob, possibly more output */ |
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254 if (k > 7) /* return unused byte, if any */ |
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255 { |
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256 Assert(k < 16, "inflate_codes grabbed too many bytes") |
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257 k -= 8; |
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258 n++; |
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259 p--; /* can always return one */ |
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260 } |
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261 FLUSH |
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262 if (s->read != s->write) |
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263 LEAVE |
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264 c->mode = END; |
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265 case END: |
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266 r = Z_STREAM_END; |
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267 LEAVE |
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268 case BADCODE: /* x: got error */ |
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269 r = Z_DATA_ERROR; |
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270 LEAVE |
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271 default: |
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272 r = Z_STREAM_ERROR; |
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273 LEAVE |
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274 } |
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275 #ifdef NEED_DUMMY_RETURN |
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276 return Z_STREAM_ERROR; /* Some dumb compilers complain without this */ |
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277 #endif |
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278 } |
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279 |
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280 |
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281 void inflate_codes_free(c, z) |
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282 inflate_codes_statef *c; |
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283 z_streamp z; |
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284 { |
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285 ZFREE(z, c); |
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286 Tracev((stderr, "inflate: codes free\n")); |
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287 } |
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