1 | /* xdelta 3 - delta compression tools and library |
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2 | * Copyright (C) 2002, 2003, 2006, 2007. Joshua P. MacDonald |
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3 | * |
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4 | * This program is free software; you can redistribute it and/or modify |
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5 | * it under the terms of the GNU General Public License as published by |
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6 | * the Free Software Foundation; either version 2 of the License, or |
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7 | * (at your option) any later version. |
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8 | * |
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9 | * This program is distributed in the hope that it will be useful, |
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10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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12 | * GNU General Public License for more details. |
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13 | * |
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14 | * You should have received a copy of the GNU General Public License |
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15 | * along with this program; if not, write to the Free Software |
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16 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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17 | */ |
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18 | |
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19 | #ifndef _XDELTA3_SECOND_H_ |
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20 | #define _XDELTA3_SECOND_H_ |
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21 | |
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22 | /****************************************************************************************** |
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23 | Secondary compression |
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24 | ******************************************************************************************/ |
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25 | |
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26 | #define xd3_sec_data(s) ((s)->sec_stream_d) |
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27 | #define xd3_sec_inst(s) ((s)->sec_stream_i) |
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28 | #define xd3_sec_addr(s) ((s)->sec_stream_a) |
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29 | |
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30 | struct _xd3_sec_type |
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31 | { |
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32 | int id; |
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33 | const char *name; |
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34 | xd3_secondary_flags flags; |
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35 | |
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36 | /* xd3_sec_stream is opaque to the generic code */ |
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37 | xd3_sec_stream* (*alloc) (xd3_stream *stream); |
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38 | void (*destroy) (xd3_stream *stream, |
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39 | xd3_sec_stream *sec); |
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40 | void (*init) (xd3_sec_stream *sec); |
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41 | int (*decode) (xd3_stream *stream, |
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42 | xd3_sec_stream *sec_stream, |
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43 | const uint8_t **input, |
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44 | const uint8_t *input_end, |
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45 | uint8_t **output, |
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46 | const uint8_t *output_end); |
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47 | #if XD3_ENCODER |
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48 | int (*encode) (xd3_stream *stream, |
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49 | xd3_sec_stream *sec_stream, |
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50 | xd3_output *input, |
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51 | xd3_output *output, |
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52 | xd3_sec_cfg *cfg); |
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53 | #endif |
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54 | }; |
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55 | |
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56 | #define BIT_STATE_ENCODE_INIT { 0, 1 } |
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57 | #define BIT_STATE_DECODE_INIT { 0, 0x100 } |
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58 | |
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59 | typedef struct _bit_state bit_state; |
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60 | struct _bit_state |
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61 | { |
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62 | usize_t cur_byte; |
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63 | usize_t cur_mask; |
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64 | }; |
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65 | |
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66 | static INLINE void xd3_bit_state_encode_init (bit_state *bits) |
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67 | { |
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68 | bits->cur_byte = 0; |
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69 | bits->cur_mask = 1; |
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70 | } |
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71 | |
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72 | static INLINE int xd3_decode_bits (xd3_stream *stream, |
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73 | bit_state *bits, |
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74 | const uint8_t **input, |
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75 | const uint8_t *input_max, |
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76 | usize_t nbits, |
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77 | usize_t *valuep) |
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78 | { |
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79 | usize_t value = 0; |
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80 | usize_t vmask = 1 << nbits; |
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81 | |
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82 | if (bits->cur_mask == 0x100) { goto next_byte; } |
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83 | |
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84 | for (;;) |
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85 | { |
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86 | do |
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87 | { |
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88 | vmask >>= 1; |
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89 | |
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90 | if (bits->cur_byte & bits->cur_mask) |
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91 | { |
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92 | value |= vmask; |
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93 | } |
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94 | |
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95 | bits->cur_mask <<= 1; |
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96 | |
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97 | if (vmask == 1) { goto done; } |
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98 | } |
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99 | while (bits->cur_mask != 0x100); |
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100 | |
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101 | next_byte: |
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102 | |
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103 | if (*input == input_max) |
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104 | { |
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105 | stream->msg = "secondary decoder end of input"; |
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106 | return XD3_INTERNAL; |
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107 | } |
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108 | |
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109 | bits->cur_byte = *(*input)++; |
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110 | bits->cur_mask = 1; |
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111 | } |
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112 | |
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113 | done: |
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114 | |
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115 | IF_DEBUG2 (DP(RINT "(d) %u ", value)); |
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116 | |
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117 | (*valuep) = value; |
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118 | return 0; |
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119 | } |
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120 | |
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121 | #if REGRESSION_TEST |
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122 | /* There may be extra bits at the end of secondary decompression, this macro checks for |
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123 | * non-zero bits. This is overly strict, but helps pass the single-bit-error regression |
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124 | * test. */ |
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125 | static int |
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126 | xd3_test_clean_bits (xd3_stream *stream, bit_state *bits) |
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127 | { |
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128 | for (; bits->cur_mask != 0x100; bits->cur_mask <<= 1) |
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129 | { |
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130 | if (bits->cur_byte & bits->cur_mask) |
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131 | { |
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132 | stream->msg = "secondary decoder garbage"; |
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133 | return XD3_INTERNAL; |
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134 | } |
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135 | } |
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136 | |
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137 | return 0; |
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138 | } |
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139 | #endif |
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140 | |
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141 | static xd3_sec_stream* |
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142 | xd3_get_secondary (xd3_stream *stream, xd3_sec_stream **sec_streamp) |
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143 | { |
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144 | xd3_sec_stream *sec_stream; |
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145 | |
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146 | if ((sec_stream = *sec_streamp) == NULL) |
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147 | { |
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148 | if ((*sec_streamp = stream->sec_type->alloc (stream)) == NULL) |
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149 | { |
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150 | return NULL; |
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151 | } |
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152 | |
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153 | sec_stream = *sec_streamp; |
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154 | |
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155 | /* If cuumulative stats, init once. */ |
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156 | stream->sec_type->init (sec_stream); |
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157 | } |
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158 | |
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159 | return sec_stream; |
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160 | } |
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161 | |
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162 | static int |
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163 | xd3_decode_secondary (xd3_stream *stream, |
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164 | xd3_desect *sect, |
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165 | xd3_sec_stream **sec_streamp) |
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166 | { |
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167 | xd3_sec_stream *sec_stream; |
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168 | uint32_t dec_size; |
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169 | uint8_t *out_used; |
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170 | int ret; |
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171 | |
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172 | if ((sec_stream = xd3_get_secondary (stream, sec_streamp)) == NULL) { return ENOMEM; } |
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173 | |
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174 | /* Decode the size, allocate the buffer. */ |
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175 | if ((ret = xd3_read_size (stream, & sect->buf, sect->buf_max, & dec_size)) || |
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176 | (ret = xd3_decode_allocate (stream, dec_size, & sect->copied2, & sect->alloc2, NULL, NULL))) |
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177 | { |
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178 | return ret; |
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179 | } |
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180 | |
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181 | out_used = sect->copied2; |
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182 | |
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183 | if ((ret = stream->sec_type->decode (stream, sec_stream, |
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184 | & sect->buf, sect->buf_max, |
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185 | & out_used, out_used + dec_size))) { return ret; } |
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186 | |
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187 | if (sect->buf != sect->buf_max) |
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188 | { |
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189 | stream->msg = "secondary decoder finished with unused input"; |
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190 | return XD3_INTERNAL; |
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191 | } |
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192 | |
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193 | if (out_used != sect->copied2 + dec_size) |
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194 | { |
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195 | stream->msg = "secondary decoder short output"; |
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196 | return XD3_INTERNAL; |
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197 | } |
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198 | |
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199 | sect->buf = sect->copied2; |
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200 | sect->buf_max = sect->copied2 + dec_size; |
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201 | |
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202 | return 0; |
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203 | } |
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204 | |
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205 | #if XD3_ENCODER |
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206 | /* OPT: Should these be inline? */ |
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207 | static INLINE int xd3_encode_bit (xd3_stream *stream, |
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208 | xd3_output **output, |
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209 | bit_state *bits, |
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210 | int bit) |
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211 | { |
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212 | int ret; |
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213 | |
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214 | if (bit) |
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215 | { |
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216 | bits->cur_byte |= bits->cur_mask; |
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217 | } |
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218 | |
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219 | /* OPT: Might help to buffer more than 8 bits at once. */ |
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220 | if (bits->cur_mask == 0x80) |
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221 | { |
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222 | if ((ret = xd3_emit_byte (stream, output, bits->cur_byte)) != 0) { return ret; } |
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223 | |
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224 | bits->cur_mask = 1; |
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225 | bits->cur_byte = 0; |
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226 | } |
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227 | else |
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228 | { |
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229 | bits->cur_mask <<= 1; |
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230 | } |
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231 | |
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232 | return 0; |
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233 | } |
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234 | |
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235 | static INLINE int xd3_flush_bits (xd3_stream *stream, |
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236 | xd3_output **output, |
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237 | bit_state *bits) |
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238 | { |
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239 | return (bits->cur_mask == 1) ? 0 : xd3_emit_byte (stream, output, bits->cur_byte); |
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240 | } |
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241 | |
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242 | static INLINE int xd3_encode_bits (xd3_stream *stream, |
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243 | xd3_output **output, |
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244 | bit_state *bits, |
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245 | usize_t nbits, |
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246 | usize_t value) |
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247 | { |
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248 | int ret; |
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249 | usize_t mask = 1 << nbits; |
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250 | |
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251 | XD3_ASSERT (nbits > 0); |
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252 | XD3_ASSERT (nbits < sizeof (usize_t) * 8); |
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253 | XD3_ASSERT (value < mask); |
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254 | |
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255 | do |
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256 | { |
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257 | mask >>= 1; |
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258 | |
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259 | if ((ret = xd3_encode_bit (stream, output, bits, value & mask))) { return ret; } |
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260 | } |
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261 | while (mask != 1); |
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262 | |
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263 | IF_DEBUG2 (DP(RINT "(e) %u ", value)); |
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264 | |
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265 | return 0; |
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266 | } |
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267 | |
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268 | static int |
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269 | xd3_encode_secondary (xd3_stream *stream, |
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270 | xd3_output **head, |
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271 | xd3_output **tail, |
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272 | xd3_sec_stream **sec_streamp, |
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273 | xd3_sec_cfg *cfg, |
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274 | int *did_it) |
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275 | { |
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276 | xd3_sec_stream *sec_stream; |
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277 | xd3_output *tmp_head; |
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278 | xd3_output *tmp_tail; |
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279 | |
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280 | usize_t comp_size; |
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281 | usize_t orig_size; |
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282 | |
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283 | int ret; |
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284 | |
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285 | orig_size = xd3_sizeof_output (*head); |
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286 | |
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287 | if (orig_size < SECONDARY_MIN_INPUT) { return 0; } |
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288 | |
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289 | if ((sec_stream = xd3_get_secondary (stream, sec_streamp)) == NULL) { return ENOMEM; } |
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290 | |
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291 | tmp_head = xd3_alloc_output (stream, NULL); |
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292 | |
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293 | /* Encode the size, encode the data. @@ Encoding the size makes it simpler, but is a |
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294 | * little gross. Should not need the entire section in contiguous memory, but it is |
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295 | * much easier this way. */ |
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296 | if ((ret = xd3_emit_size (stream, & tmp_head, orig_size)) || |
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297 | (ret = stream->sec_type->encode (stream, sec_stream, *head, tmp_head, cfg))) { goto getout; } |
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298 | |
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299 | /* If the secondary compressor determines its no good, it returns XD3_NOSECOND. */ |
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300 | |
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301 | /* Setup tmp_tail, comp_size */ |
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302 | tmp_tail = tmp_head; |
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303 | comp_size = tmp_head->next; |
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304 | |
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305 | while (tmp_tail->next_page != NULL) |
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306 | { |
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307 | tmp_tail = tmp_tail->next_page; |
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308 | comp_size += tmp_tail->next; |
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309 | } |
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310 | |
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311 | XD3_ASSERT (comp_size == xd3_sizeof_output (tmp_head)); |
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312 | XD3_ASSERT (tmp_tail != NULL); |
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313 | |
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314 | if (comp_size < (orig_size - SECONDARY_MIN_SAVINGS)) |
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315 | { |
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316 | IF_DEBUG1(DP(RINT "secondary saved %u bytes: %u -> %u (%0.2f%%)\n", |
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317 | orig_size - comp_size, orig_size, comp_size, |
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318 | (double) comp_size / (double) orig_size)); |
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319 | |
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320 | xd3_free_output (stream, *head); |
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321 | |
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322 | *head = tmp_head; |
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323 | *tail = tmp_tail; |
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324 | *did_it = 1; |
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325 | } |
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326 | else |
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327 | { |
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328 | getout: |
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329 | if (ret == XD3_NOSECOND) { ret = 0; } |
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330 | xd3_free_output (stream, tmp_head); |
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331 | } |
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332 | |
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333 | return ret; |
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334 | } |
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335 | #endif /* XD3_ENCODER */ |
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336 | #endif /* _XDELTA3_SECOND_H_ */ |
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