1 | /* implementation of the LZO1X decompression algorithm
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2 |
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3 | This file is part of the LZO real-time data compression library.
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4 |
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5 | Copyright (C) 1996..2008 Markus Franz Xaver Johannes Oberhumer
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6 | All Rights Reserved.
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7 |
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8 | Markus F.X.J. Oberhumer <markus@oberhumer.com>
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9 | http://www.oberhumer.com/opensource/lzo/
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10 |
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11 | The LZO library is free software; you can redistribute it and/or
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12 | modify it under the terms of the GNU General Public License as
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13 | published by the Free Software Foundation; either version 2 of
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14 | the License, or (at your option) any later version.
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15 |
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16 | The LZO library is distributed in the hope that it will be useful,
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17 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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19 | GNU General Public License for more details.
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20 |
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21 | You should have received a copy of the GNU General Public License
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22 | along with the LZO library; see the file COPYING.
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23 | If not, write to the Free Software Foundation, Inc.,
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24 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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25 | */
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26 | #include "libbb.h"
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27 | #include "liblzo.h"
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28 |
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29 | /***********************************************************************
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30 | // decompress a block of data.
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31 | ************************************************************************/
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32 | /* safe decompression with overrun testing */
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33 | int lzo1x_decompress_safe(const uint8_t* in, unsigned in_len,
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34 | uint8_t* out, unsigned* out_len,
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35 | void* wrkmem UNUSED_PARAM)
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36 | {
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37 | register uint8_t* op;
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38 | register const uint8_t* ip;
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39 | register unsigned t;
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40 | #if defined(COPY_DICT)
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41 | unsigned m_off;
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42 | const uint8_t* dict_end;
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43 | #else
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44 | register const uint8_t* m_pos = NULL; /* possibly not needed */
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45 | #endif
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46 | const uint8_t* const ip_end = in + in_len;
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47 | #if defined(HAVE_ANY_OP)
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48 | uint8_t* const op_end = out + *out_len;
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49 | #endif
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50 | #if defined(LZO1Z)
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51 | unsigned last_m_off = 0;
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52 | #endif
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53 |
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54 | // LZO_UNUSED(wrkmem);
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55 |
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56 | #if defined(COPY_DICT)
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57 | if (dict) {
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58 | if (dict_len > M4_MAX_OFFSET) {
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59 | dict += dict_len - M4_MAX_OFFSET;
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60 | dict_len = M4_MAX_OFFSET;
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61 | }
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62 | dict_end = dict + dict_len;
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63 | } else {
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64 | dict_len = 0;
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65 | dict_end = NULL;
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66 | }
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67 | #endif /* COPY_DICT */
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68 |
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69 | *out_len = 0;
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70 |
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71 | op = out;
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72 | ip = in;
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73 |
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74 | if (*ip > 17) {
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75 | t = *ip++ - 17;
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76 | if (t < 4)
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77 | goto match_next;
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78 | assert(t > 0); NEED_OP(t); NEED_IP(t+1);
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79 | do *op++ = *ip++; while (--t > 0);
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80 | goto first_literal_run;
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81 | }
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82 |
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83 | while (TEST_IP && TEST_OP) {
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84 | t = *ip++;
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85 | if (t >= 16)
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86 | goto match;
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87 | /* a literal run */
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88 | if (t == 0) {
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89 | NEED_IP(1);
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90 | while (*ip == 0) {
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91 | t += 255;
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92 | ip++;
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93 | NEED_IP(1);
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94 | }
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95 | t += 15 + *ip++;
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96 | }
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97 | /* copy literals */
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98 | assert(t > 0);
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99 | NEED_OP(t+3);
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100 | NEED_IP(t+4);
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101 | #if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
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102 | # if !defined(LZO_UNALIGNED_OK_4)
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103 | if (PTR_ALIGNED2_4(op, ip))
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104 | # endif
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105 | {
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106 | COPY4(op, ip);
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107 | op += 4;
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108 | ip += 4;
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109 | if (--t > 0) {
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110 | if (t >= 4) {
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111 | do {
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112 | COPY4(op, ip);
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113 | op += 4;
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114 | ip += 4;
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115 | t -= 4;
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116 | } while (t >= 4);
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117 | if (t > 0)
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118 | do *op++ = *ip++; while (--t > 0);
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119 | } else {
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120 | do *op++ = *ip++; while (--t > 0);
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121 | }
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122 | }
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123 | }
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124 | # if !defined(LZO_UNALIGNED_OK_4)
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125 | else
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126 | # endif
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127 | #endif
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128 | #if !defined(LZO_UNALIGNED_OK_4)
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129 | {
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130 | *op++ = *ip++;
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131 | *op++ = *ip++;
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132 | *op++ = *ip++;
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133 | do *op++ = *ip++; while (--t > 0);
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134 | }
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135 | #endif
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136 |
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137 | first_literal_run:
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138 | t = *ip++;
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139 | if (t >= 16)
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140 | goto match;
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141 | #if defined(COPY_DICT)
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142 | #if defined(LZO1Z)
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143 | m_off = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
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144 | last_m_off = m_off;
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145 | #else
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146 | m_off = (1 + M2_MAX_OFFSET) + (t >> 2) + (*ip++ << 2);
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147 | #endif
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148 | NEED_OP(3);
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149 | t = 3; COPY_DICT(t,m_off)
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150 | #else /* !COPY_DICT */
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151 | #if defined(LZO1Z)
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152 | t = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
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153 | m_pos = op - t;
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154 | last_m_off = t;
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155 | #else
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156 | m_pos = op - (1 + M2_MAX_OFFSET);
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157 | m_pos -= t >> 2;
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158 | m_pos -= *ip++ << 2;
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159 | #endif
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160 | TEST_LB(m_pos); NEED_OP(3);
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161 | *op++ = *m_pos++;
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162 | *op++ = *m_pos++;
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163 | *op++ = *m_pos;
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164 | #endif /* COPY_DICT */
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165 | goto match_done;
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166 |
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167 | /* handle matches */
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168 | do {
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169 | match:
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170 | if (t >= 64) { /* a M2 match */
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171 | #if defined(COPY_DICT)
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172 | #if defined(LZO1X)
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173 | m_off = 1 + ((t >> 2) & 7) + (*ip++ << 3);
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174 | t = (t >> 5) - 1;
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175 | #elif defined(LZO1Y)
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176 | m_off = 1 + ((t >> 2) & 3) + (*ip++ << 2);
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177 | t = (t >> 4) - 3;
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178 | #elif defined(LZO1Z)
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179 | m_off = t & 0x1f;
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180 | if (m_off >= 0x1c)
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181 | m_off = last_m_off;
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182 | else {
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183 | m_off = 1 + (m_off << 6) + (*ip++ >> 2);
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184 | last_m_off = m_off;
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185 | }
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186 | t = (t >> 5) - 1;
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187 | #endif
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188 | #else /* !COPY_DICT */
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189 | #if defined(LZO1X)
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190 | m_pos = op - 1;
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191 | m_pos -= (t >> 2) & 7;
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192 | m_pos -= *ip++ << 3;
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193 | t = (t >> 5) - 1;
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194 | #elif defined(LZO1Y)
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195 | m_pos = op - 1;
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196 | m_pos -= (t >> 2) & 3;
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197 | m_pos -= *ip++ << 2;
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198 | t = (t >> 4) - 3;
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199 | #elif defined(LZO1Z)
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200 | {
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201 | unsigned off = t & 0x1f;
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202 | m_pos = op;
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203 | if (off >= 0x1c) {
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204 | assert(last_m_off > 0);
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205 | m_pos -= last_m_off;
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206 | } else {
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207 | off = 1 + (off << 6) + (*ip++ >> 2);
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208 | m_pos -= off;
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209 | last_m_off = off;
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210 | }
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211 | }
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212 | t = (t >> 5) - 1;
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213 | #endif
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214 | TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
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215 | goto copy_match;
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216 | #endif /* COPY_DICT */
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217 | }
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218 | else if (t >= 32) { /* a M3 match */
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219 | t &= 31;
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220 | if (t == 0) {
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221 | NEED_IP(1);
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222 | while (*ip == 0) {
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223 | t += 255;
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224 | ip++;
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225 | NEED_IP(1);
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226 | }
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227 | t += 31 + *ip++;
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228 | }
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229 | #if defined(COPY_DICT)
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230 | #if defined(LZO1Z)
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231 | m_off = 1 + (ip[0] << 6) + (ip[1] >> 2);
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232 | last_m_off = m_off;
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233 | #else
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234 | m_off = 1 + (ip[0] >> 2) + (ip[1] << 6);
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235 | #endif
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236 | #else /* !COPY_DICT */
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237 | #if defined(LZO1Z)
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238 | {
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239 | unsigned off = 1 + (ip[0] << 6) + (ip[1] >> 2);
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240 | m_pos = op - off;
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241 | last_m_off = off;
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242 | }
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243 | #elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
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244 | m_pos = op - 1;
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245 | m_pos -= (* (const lzo_ushortp) ip) >> 2;
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246 | #else
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247 | m_pos = op - 1;
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248 | m_pos -= (ip[0] >> 2) + (ip[1] << 6);
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249 | #endif
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250 | #endif /* COPY_DICT */
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251 | ip += 2;
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252 | }
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253 | else if (t >= 16) { /* a M4 match */
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254 | #if defined(COPY_DICT)
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255 | m_off = (t & 8) << 11;
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256 | #else /* !COPY_DICT */
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257 | m_pos = op;
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258 | m_pos -= (t & 8) << 11;
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259 | #endif /* COPY_DICT */
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260 | t &= 7;
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261 | if (t == 0) {
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262 | NEED_IP(1);
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263 | while (*ip == 0) {
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264 | t += 255;
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265 | ip++;
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266 | NEED_IP(1);
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267 | }
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268 | t += 7 + *ip++;
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269 | }
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270 | #if defined(COPY_DICT)
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271 | #if defined(LZO1Z)
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272 | m_off += (ip[0] << 6) + (ip[1] >> 2);
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273 | #else
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274 | m_off += (ip[0] >> 2) + (ip[1] << 6);
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275 | #endif
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276 | ip += 2;
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277 | if (m_off == 0)
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278 | goto eof_found;
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279 | m_off += 0x4000;
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280 | #if defined(LZO1Z)
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281 | last_m_off = m_off;
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282 | #endif
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283 | #else /* !COPY_DICT */
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284 | #if defined(LZO1Z)
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285 | m_pos -= (ip[0] << 6) + (ip[1] >> 2);
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286 | #elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
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287 | m_pos -= (* (const lzo_ushortp) ip) >> 2;
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288 | #else
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289 | m_pos -= (ip[0] >> 2) + (ip[1] << 6);
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290 | #endif
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291 | ip += 2;
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292 | if (m_pos == op)
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293 | goto eof_found;
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294 | m_pos -= 0x4000;
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295 | #if defined(LZO1Z)
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296 | last_m_off = pd((const uint8_t*)op, m_pos);
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297 | #endif
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298 | #endif /* COPY_DICT */
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299 | }
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300 | else { /* a M1 match */
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301 | #if defined(COPY_DICT)
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302 | #if defined(LZO1Z)
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303 | m_off = 1 + (t << 6) + (*ip++ >> 2);
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304 | last_m_off = m_off;
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305 | #else
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306 | m_off = 1 + (t >> 2) + (*ip++ << 2);
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307 | #endif
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308 | NEED_OP(2);
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309 | t = 2; COPY_DICT(t,m_off)
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310 | #else /* !COPY_DICT */
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311 | #if defined(LZO1Z)
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312 | t = 1 + (t << 6) + (*ip++ >> 2);
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313 | m_pos = op - t;
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314 | last_m_off = t;
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315 | #else
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316 | m_pos = op - 1;
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317 | m_pos -= t >> 2;
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318 | m_pos -= *ip++ << 2;
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319 | #endif
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320 | TEST_LB(m_pos); NEED_OP(2);
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321 | *op++ = *m_pos++;
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322 | *op++ = *m_pos;
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323 | #endif /* COPY_DICT */
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324 | goto match_done;
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325 | }
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326 |
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327 | /* copy match */
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328 | #if defined(COPY_DICT)
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329 |
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330 | NEED_OP(t+3-1);
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331 | t += 3-1; COPY_DICT(t,m_off)
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332 |
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333 | #else /* !COPY_DICT */
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334 |
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335 | TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
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336 | #if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
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337 | # if !defined(LZO_UNALIGNED_OK_4)
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338 | if (t >= 2 * 4 - (3 - 1) && PTR_ALIGNED2_4(op,m_pos)) {
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339 | assert((op - m_pos) >= 4); /* both pointers are aligned */
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340 | # else
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341 | if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
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342 | # endif
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343 | COPY4(op,m_pos);
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344 | op += 4; m_pos += 4; t -= 4 - (3 - 1);
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345 | do {
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346 | COPY4(op,m_pos);
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347 | op += 4; m_pos += 4; t -= 4;
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348 | } while (t >= 4);
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349 | if (t > 0)
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350 | do *op++ = *m_pos++; while (--t > 0);
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351 | }
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352 | else
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353 | #endif
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354 | {
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355 | copy_match:
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356 | *op++ = *m_pos++; *op++ = *m_pos++;
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357 | do *op++ = *m_pos++; while (--t > 0);
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358 | }
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359 |
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360 | #endif /* COPY_DICT */
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361 |
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362 | match_done:
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363 | #if defined(LZO1Z)
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364 | t = ip[-1] & 3;
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365 | #else
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366 | t = ip[-2] & 3;
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367 | #endif
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368 | if (t == 0)
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369 | break;
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370 |
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371 | /* copy literals */
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372 | match_next:
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373 | assert(t > 0);
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374 | assert(t < 4);
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375 | NEED_OP(t);
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376 | NEED_IP(t+1);
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377 | #if 0
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378 | do *op++ = *ip++; while (--t > 0);
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379 | #else
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380 | *op++ = *ip++;
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381 | if (t > 1) {
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382 | *op++ = *ip++;
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383 | if (t > 2)
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384 | *op++ = *ip++;
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385 | }
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386 | #endif
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387 | t = *ip++;
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388 | } while (TEST_IP && TEST_OP);
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389 | }
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390 |
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391 | //#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
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392 | /* no EOF code was found */
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393 | *out_len = pd(op, out);
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394 | return LZO_E_EOF_NOT_FOUND;
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395 | //#endif
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396 |
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397 | eof_found:
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398 | assert(t == 1);
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399 | *out_len = pd(op, out);
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400 | return (ip == ip_end ? LZO_E_OK :
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401 | (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
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402 |
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403 | //#if defined(HAVE_NEED_IP)
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404 | input_overrun:
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405 | *out_len = pd(op, out);
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406 | return LZO_E_INPUT_OVERRUN;
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407 | //#endif
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408 |
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409 | //#if defined(HAVE_NEED_OP)
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410 | output_overrun:
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411 | *out_len = pd(op, out);
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412 | return LZO_E_OUTPUT_OVERRUN;
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413 | //#endif
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414 |
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415 | //#if defined(LZO_TEST_OVERRUN_LOOKBEHIND)
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416 | lookbehind_overrun:
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417 | *out_len = pd(op, out);
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418 | return LZO_E_LOOKBEHIND_OVERRUN;
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419 | //#endif
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420 | }
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