1 | |
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2 | /* pngpread.c - read a png file in push mode |
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3 | * |
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4 | * Last changed in libpng 1.5.11 [June 14, 2012] |
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5 | * Copyright (c) 1998-2012 Glenn Randers-Pehrson |
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6 | * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
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7 | * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
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8 | * |
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9 | * This code is released under the libpng license. |
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10 | * For conditions of distribution and use, see the disclaimer |
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11 | * and license in png.h |
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12 | */ |
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13 | |
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14 | #include "pngpriv.h" |
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15 | |
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16 | #ifdef PNG_PROGRESSIVE_READ_SUPPORTED |
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17 | |
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18 | /* Push model modes */ |
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19 | #define PNG_READ_SIG_MODE 0 |
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20 | #define PNG_READ_CHUNK_MODE 1 |
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21 | #define PNG_READ_IDAT_MODE 2 |
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22 | #define PNG_SKIP_MODE 3 |
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23 | #define PNG_READ_tEXt_MODE 4 |
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24 | #define PNG_READ_zTXt_MODE 5 |
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25 | #define PNG_READ_DONE_MODE 6 |
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26 | #define PNG_READ_iTXt_MODE 7 |
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27 | #define PNG_ERROR_MODE 8 |
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28 | |
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29 | void PNGAPI |
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30 | png_process_data(png_structp png_ptr, png_infop info_ptr, |
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31 | png_bytep buffer, png_size_t buffer_size) |
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32 | { |
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33 | if (png_ptr == NULL || info_ptr == NULL) |
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34 | return; |
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35 | |
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36 | png_push_restore_buffer(png_ptr, buffer, buffer_size); |
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37 | |
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38 | while (png_ptr->buffer_size) |
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39 | { |
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40 | png_process_some_data(png_ptr, info_ptr); |
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41 | } |
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42 | } |
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43 | |
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44 | png_size_t PNGAPI |
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45 | png_process_data_pause(png_structp png_ptr, int save) |
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46 | { |
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47 | if (png_ptr != NULL) |
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48 | { |
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49 | /* It's easiest for the caller if we do the save, then the caller doesn't |
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50 | * have to supply the same data again: |
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51 | */ |
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52 | if (save) |
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53 | png_push_save_buffer(png_ptr); |
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54 | else |
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55 | { |
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56 | /* This includes any pending saved bytes: */ |
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57 | png_size_t remaining = png_ptr->buffer_size; |
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58 | png_ptr->buffer_size = 0; |
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59 | |
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60 | /* So subtract the saved buffer size, unless all the data |
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61 | * is actually 'saved', in which case we just return 0 |
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62 | */ |
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63 | if (png_ptr->save_buffer_size < remaining) |
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64 | return remaining - png_ptr->save_buffer_size; |
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65 | } |
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66 | } |
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67 | |
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68 | return 0; |
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69 | } |
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70 | |
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71 | png_uint_32 PNGAPI |
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72 | png_process_data_skip(png_structp png_ptr) |
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73 | { |
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74 | png_uint_32 remaining = 0; |
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75 | |
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76 | if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE && |
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77 | png_ptr->skip_length > 0) |
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78 | { |
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79 | /* At the end of png_process_data the buffer size must be 0 (see the loop |
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80 | * above) so we can detect a broken call here: |
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81 | */ |
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82 | if (png_ptr->buffer_size != 0) |
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83 | png_error(png_ptr, |
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84 | "png_process_data_skip called inside png_process_data"); |
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85 | |
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86 | /* If is impossible for there to be a saved buffer at this point - |
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87 | * otherwise we could not be in SKIP mode. This will also happen if |
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88 | * png_process_skip is called inside png_process_data (but only very |
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89 | * rarely.) |
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90 | */ |
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91 | if (png_ptr->save_buffer_size != 0) |
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92 | png_error(png_ptr, "png_process_data_skip called with saved data"); |
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93 | |
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94 | remaining = png_ptr->skip_length; |
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95 | png_ptr->skip_length = 0; |
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96 | png_ptr->process_mode = PNG_READ_CHUNK_MODE; |
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97 | } |
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98 | |
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99 | return remaining; |
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100 | } |
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101 | |
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102 | /* What we do with the incoming data depends on what we were previously |
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103 | * doing before we ran out of data... |
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104 | */ |
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105 | void /* PRIVATE */ |
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106 | png_process_some_data(png_structp png_ptr, png_infop info_ptr) |
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107 | { |
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108 | if (png_ptr == NULL) |
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109 | return; |
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110 | |
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111 | switch (png_ptr->process_mode) |
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112 | { |
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113 | case PNG_READ_SIG_MODE: |
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114 | { |
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115 | png_push_read_sig(png_ptr, info_ptr); |
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116 | break; |
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117 | } |
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118 | |
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119 | case PNG_READ_CHUNK_MODE: |
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120 | { |
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121 | png_push_read_chunk(png_ptr, info_ptr); |
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122 | break; |
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123 | } |
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124 | |
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125 | case PNG_READ_IDAT_MODE: |
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126 | { |
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127 | png_push_read_IDAT(png_ptr); |
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128 | break; |
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129 | } |
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130 | |
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131 | case PNG_SKIP_MODE: |
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132 | { |
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133 | png_push_crc_finish(png_ptr); |
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134 | break; |
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135 | } |
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136 | |
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137 | default: |
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138 | { |
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139 | png_ptr->buffer_size = 0; |
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140 | break; |
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141 | } |
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142 | } |
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143 | } |
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144 | |
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145 | /* Read any remaining signature bytes from the stream and compare them with |
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146 | * the correct PNG signature. It is possible that this routine is called |
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147 | * with bytes already read from the signature, either because they have been |
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148 | * checked by the calling application, or because of multiple calls to this |
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149 | * routine. |
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150 | */ |
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151 | void /* PRIVATE */ |
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152 | png_push_read_sig(png_structp png_ptr, png_infop info_ptr) |
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153 | { |
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154 | png_size_t num_checked = png_ptr->sig_bytes, |
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155 | num_to_check = 8 - num_checked; |
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156 | |
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157 | if (png_ptr->buffer_size < num_to_check) |
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158 | { |
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159 | num_to_check = png_ptr->buffer_size; |
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160 | } |
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161 | |
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162 | png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]), |
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163 | num_to_check); |
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164 | png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check); |
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165 | |
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166 | if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check)) |
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167 | { |
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168 | if (num_checked < 4 && |
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169 | png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4)) |
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170 | png_error(png_ptr, "Not a PNG file"); |
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171 | |
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172 | else |
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173 | png_error(png_ptr, "PNG file corrupted by ASCII conversion"); |
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174 | } |
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175 | |
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176 | else |
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177 | { |
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178 | if (png_ptr->sig_bytes >= 8) |
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179 | { |
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180 | png_ptr->process_mode = PNG_READ_CHUNK_MODE; |
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181 | } |
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182 | } |
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183 | } |
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184 | |
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185 | void /* PRIVATE */ |
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186 | png_push_read_chunk(png_structp png_ptr, png_infop info_ptr) |
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187 | { |
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188 | png_uint_32 chunk_name; |
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189 | |
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190 | /* First we make sure we have enough data for the 4 byte chunk name |
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191 | * and the 4 byte chunk length before proceeding with decoding the |
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192 | * chunk data. To fully decode each of these chunks, we also make |
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193 | * sure we have enough data in the buffer for the 4 byte CRC at the |
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194 | * end of every chunk (except IDAT, which is handled separately). |
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195 | */ |
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196 | if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) |
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197 | { |
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198 | png_byte chunk_length[4]; |
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199 | png_byte chunk_tag[4]; |
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200 | |
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201 | if (png_ptr->buffer_size < 8) |
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202 | { |
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203 | png_push_save_buffer(png_ptr); |
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204 | return; |
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205 | } |
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206 | |
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207 | png_push_fill_buffer(png_ptr, chunk_length, 4); |
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208 | png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length); |
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209 | png_reset_crc(png_ptr); |
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210 | png_crc_read(png_ptr, chunk_tag, 4); |
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211 | png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag); |
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212 | png_check_chunk_name(png_ptr, png_ptr->chunk_name); |
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213 | png_ptr->mode |= PNG_HAVE_CHUNK_HEADER; |
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214 | } |
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215 | |
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216 | chunk_name = png_ptr->chunk_name; |
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217 | |
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218 | if (chunk_name == png_IDAT) |
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219 | { |
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220 | /* This is here above the if/else case statement below because if the |
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221 | * unknown handling marks 'IDAT' as unknown then the IDAT handling case is |
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222 | * completely skipped. |
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223 | * |
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224 | * TODO: there must be a better way of doing this. |
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225 | */ |
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226 | if (png_ptr->mode & PNG_AFTER_IDAT) |
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227 | png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT; |
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228 | } |
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229 | |
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230 | if (chunk_name == png_IHDR) |
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231 | { |
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232 | if (png_ptr->push_length != 13) |
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233 | png_error(png_ptr, "Invalid IHDR length"); |
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234 | |
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235 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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236 | { |
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237 | png_push_save_buffer(png_ptr); |
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238 | return; |
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239 | } |
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240 | |
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241 | png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length); |
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242 | } |
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243 | |
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244 | else if (chunk_name == png_IEND) |
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245 | { |
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246 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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247 | { |
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248 | png_push_save_buffer(png_ptr); |
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249 | return; |
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250 | } |
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251 | |
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252 | png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length); |
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253 | |
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254 | png_ptr->process_mode = PNG_READ_DONE_MODE; |
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255 | png_push_have_end(png_ptr, info_ptr); |
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256 | } |
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257 | |
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258 | #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED |
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259 | else if (png_chunk_unknown_handling(png_ptr, chunk_name)) |
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260 | { |
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261 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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262 | { |
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263 | png_push_save_buffer(png_ptr); |
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264 | return; |
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265 | } |
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266 | |
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267 | if (chunk_name == png_IDAT) |
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268 | png_ptr->mode |= PNG_HAVE_IDAT; |
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269 | |
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270 | png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length); |
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271 | |
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272 | if (chunk_name == png_PLTE) |
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273 | png_ptr->mode |= PNG_HAVE_PLTE; |
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274 | |
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275 | else if (chunk_name == png_IDAT) |
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276 | { |
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277 | if (!(png_ptr->mode & PNG_HAVE_IHDR)) |
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278 | png_error(png_ptr, "Missing IHDR before IDAT"); |
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279 | |
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280 | else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && |
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281 | !(png_ptr->mode & PNG_HAVE_PLTE)) |
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282 | png_error(png_ptr, "Missing PLTE before IDAT"); |
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283 | } |
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284 | } |
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285 | #endif |
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286 | |
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287 | else if (chunk_name == png_PLTE) |
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288 | { |
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289 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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290 | { |
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291 | png_push_save_buffer(png_ptr); |
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292 | return; |
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293 | } |
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294 | png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length); |
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295 | } |
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296 | |
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297 | else if (chunk_name == png_IDAT) |
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298 | { |
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299 | /* If we reach an IDAT chunk, this means we have read all of the |
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300 | * header chunks, and we can start reading the image (or if this |
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301 | * is called after the image has been read - we have an error). |
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302 | */ |
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303 | |
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304 | if (!(png_ptr->mode & PNG_HAVE_IHDR)) |
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305 | png_error(png_ptr, "Missing IHDR before IDAT"); |
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306 | |
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307 | else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && |
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308 | !(png_ptr->mode & PNG_HAVE_PLTE)) |
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309 | png_error(png_ptr, "Missing PLTE before IDAT"); |
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310 | |
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311 | if (png_ptr->mode & PNG_HAVE_IDAT) |
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312 | { |
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313 | if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT)) |
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314 | if (png_ptr->push_length == 0) |
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315 | return; |
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316 | |
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317 | if (png_ptr->mode & PNG_AFTER_IDAT) |
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318 | png_benign_error(png_ptr, "Too many IDATs found"); |
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319 | } |
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320 | |
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321 | png_ptr->idat_size = png_ptr->push_length; |
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322 | png_ptr->mode |= PNG_HAVE_IDAT; |
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323 | png_ptr->process_mode = PNG_READ_IDAT_MODE; |
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324 | png_push_have_info(png_ptr, info_ptr); |
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325 | png_ptr->zstream.avail_out = |
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326 | (uInt) PNG_ROWBYTES(png_ptr->pixel_depth, |
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327 | png_ptr->iwidth) + 1; |
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328 | png_ptr->zstream.next_out = png_ptr->row_buf; |
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329 | return; |
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330 | } |
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331 | |
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332 | #ifdef PNG_READ_gAMA_SUPPORTED |
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333 | else if (png_ptr->chunk_name == png_gAMA) |
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334 | { |
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335 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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336 | { |
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337 | png_push_save_buffer(png_ptr); |
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338 | return; |
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339 | } |
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340 | |
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341 | png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length); |
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342 | } |
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343 | |
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344 | #endif |
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345 | #ifdef PNG_READ_sBIT_SUPPORTED |
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346 | else if (png_ptr->chunk_name == png_sBIT) |
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347 | { |
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348 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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349 | { |
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350 | png_push_save_buffer(png_ptr); |
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351 | return; |
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352 | } |
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353 | |
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354 | png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length); |
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355 | } |
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356 | |
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357 | #endif |
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358 | #ifdef PNG_READ_cHRM_SUPPORTED |
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359 | else if (png_ptr->chunk_name == png_cHRM) |
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360 | { |
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361 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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362 | { |
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363 | png_push_save_buffer(png_ptr); |
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364 | return; |
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365 | } |
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366 | |
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367 | png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length); |
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368 | } |
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369 | |
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370 | #endif |
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371 | #ifdef PNG_READ_sRGB_SUPPORTED |
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372 | else if (chunk_name == png_sRGB) |
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373 | { |
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374 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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375 | { |
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376 | png_push_save_buffer(png_ptr); |
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377 | return; |
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378 | } |
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379 | |
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380 | png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length); |
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381 | } |
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382 | |
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383 | #endif |
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384 | #ifdef PNG_READ_iCCP_SUPPORTED |
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385 | else if (png_ptr->chunk_name == png_iCCP) |
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386 | { |
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387 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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388 | { |
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389 | png_push_save_buffer(png_ptr); |
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390 | return; |
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391 | } |
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392 | |
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393 | png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length); |
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394 | } |
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395 | |
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396 | #endif |
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397 | #ifdef PNG_READ_sPLT_SUPPORTED |
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398 | else if (chunk_name == png_sPLT) |
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399 | { |
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400 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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401 | { |
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402 | png_push_save_buffer(png_ptr); |
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403 | return; |
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404 | } |
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405 | |
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406 | png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length); |
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407 | } |
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408 | |
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409 | #endif |
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410 | #ifdef PNG_READ_tRNS_SUPPORTED |
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411 | else if (chunk_name == png_tRNS) |
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412 | { |
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413 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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414 | { |
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415 | png_push_save_buffer(png_ptr); |
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416 | return; |
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417 | } |
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418 | |
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419 | png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length); |
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420 | } |
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421 | |
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422 | #endif |
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423 | #ifdef PNG_READ_bKGD_SUPPORTED |
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424 | else if (chunk_name == png_bKGD) |
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425 | { |
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426 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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427 | { |
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428 | png_push_save_buffer(png_ptr); |
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429 | return; |
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430 | } |
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431 | |
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432 | png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length); |
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433 | } |
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434 | |
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435 | #endif |
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436 | #ifdef PNG_READ_hIST_SUPPORTED |
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437 | else if (chunk_name == png_hIST) |
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438 | { |
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439 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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440 | { |
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441 | png_push_save_buffer(png_ptr); |
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442 | return; |
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443 | } |
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444 | |
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445 | png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length); |
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446 | } |
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447 | |
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448 | #endif |
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449 | #ifdef PNG_READ_pHYs_SUPPORTED |
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450 | else if (chunk_name == png_pHYs) |
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451 | { |
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452 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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453 | { |
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454 | png_push_save_buffer(png_ptr); |
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455 | return; |
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456 | } |
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457 | |
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458 | png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length); |
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459 | } |
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460 | |
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461 | #endif |
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462 | #ifdef PNG_READ_oFFs_SUPPORTED |
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463 | else if (chunk_name == png_oFFs) |
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464 | { |
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465 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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466 | { |
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467 | png_push_save_buffer(png_ptr); |
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468 | return; |
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469 | } |
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470 | |
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471 | png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length); |
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472 | } |
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473 | #endif |
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474 | |
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475 | #ifdef PNG_READ_pCAL_SUPPORTED |
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476 | else if (chunk_name == png_pCAL) |
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477 | { |
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478 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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479 | { |
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480 | png_push_save_buffer(png_ptr); |
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481 | return; |
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482 | } |
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483 | |
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484 | png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length); |
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485 | } |
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486 | |
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487 | #endif |
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488 | #ifdef PNG_READ_sCAL_SUPPORTED |
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489 | else if (chunk_name == png_sCAL) |
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490 | { |
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491 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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492 | { |
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493 | png_push_save_buffer(png_ptr); |
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494 | return; |
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495 | } |
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496 | |
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497 | png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length); |
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498 | } |
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499 | |
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500 | #endif |
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501 | #ifdef PNG_READ_tIME_SUPPORTED |
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502 | else if (chunk_name == png_tIME) |
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503 | { |
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504 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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505 | { |
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506 | png_push_save_buffer(png_ptr); |
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507 | return; |
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508 | } |
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509 | |
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510 | png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length); |
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511 | } |
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512 | |
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513 | #endif |
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514 | #ifdef PNG_READ_tEXt_SUPPORTED |
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515 | else if (chunk_name == png_tEXt) |
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516 | { |
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517 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
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518 | { |
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519 | png_push_save_buffer(png_ptr); |
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520 | return; |
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521 | } |
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522 | |
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523 | png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length); |
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524 | } |
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525 | |
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526 | #endif |
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527 | #ifdef PNG_READ_zTXt_SUPPORTED |
---|
528 | else if (chunk_name == png_zTXt) |
---|
529 | { |
---|
530 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
---|
531 | { |
---|
532 | png_push_save_buffer(png_ptr); |
---|
533 | return; |
---|
534 | } |
---|
535 | |
---|
536 | png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length); |
---|
537 | } |
---|
538 | |
---|
539 | #endif |
---|
540 | #ifdef PNG_READ_iTXt_SUPPORTED |
---|
541 | else if (chunk_name == png_iTXt) |
---|
542 | { |
---|
543 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
---|
544 | { |
---|
545 | png_push_save_buffer(png_ptr); |
---|
546 | return; |
---|
547 | } |
---|
548 | |
---|
549 | png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length); |
---|
550 | } |
---|
551 | |
---|
552 | #endif |
---|
553 | |
---|
554 | else |
---|
555 | { |
---|
556 | if (png_ptr->push_length + 4 > png_ptr->buffer_size) |
---|
557 | { |
---|
558 | png_push_save_buffer(png_ptr); |
---|
559 | return; |
---|
560 | } |
---|
561 | png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length); |
---|
562 | } |
---|
563 | |
---|
564 | png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; |
---|
565 | } |
---|
566 | |
---|
567 | void /* PRIVATE */ |
---|
568 | png_push_crc_skip(png_structp png_ptr, png_uint_32 skip) |
---|
569 | { |
---|
570 | png_ptr->process_mode = PNG_SKIP_MODE; |
---|
571 | png_ptr->skip_length = skip; |
---|
572 | } |
---|
573 | |
---|
574 | void /* PRIVATE */ |
---|
575 | png_push_crc_finish(png_structp png_ptr) |
---|
576 | { |
---|
577 | if (png_ptr->skip_length && png_ptr->save_buffer_size) |
---|
578 | { |
---|
579 | png_size_t save_size = png_ptr->save_buffer_size; |
---|
580 | png_uint_32 skip_length = png_ptr->skip_length; |
---|
581 | |
---|
582 | /* We want the smaller of 'skip_length' and 'save_buffer_size', but |
---|
583 | * they are of different types and we don't know which variable has the |
---|
584 | * fewest bits. Carefully select the smaller and cast it to the type of |
---|
585 | * the larger - this cannot overflow. Do not cast in the following test |
---|
586 | * - it will break on either 16 or 64 bit platforms. |
---|
587 | */ |
---|
588 | if (skip_length < save_size) |
---|
589 | save_size = (png_size_t)skip_length; |
---|
590 | |
---|
591 | else |
---|
592 | skip_length = (png_uint_32)save_size; |
---|
593 | |
---|
594 | png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); |
---|
595 | |
---|
596 | png_ptr->skip_length -= skip_length; |
---|
597 | png_ptr->buffer_size -= save_size; |
---|
598 | png_ptr->save_buffer_size -= save_size; |
---|
599 | png_ptr->save_buffer_ptr += save_size; |
---|
600 | } |
---|
601 | |
---|
602 | if (png_ptr->skip_length && png_ptr->current_buffer_size) |
---|
603 | { |
---|
604 | png_size_t save_size = png_ptr->current_buffer_size; |
---|
605 | png_uint_32 skip_length = png_ptr->skip_length; |
---|
606 | |
---|
607 | /* We want the smaller of 'skip_length' and 'current_buffer_size', here, |
---|
608 | * the same problem exists as above and the same solution. |
---|
609 | */ |
---|
610 | if (skip_length < save_size) |
---|
611 | save_size = (png_size_t)skip_length; |
---|
612 | |
---|
613 | else |
---|
614 | skip_length = (png_uint_32)save_size; |
---|
615 | |
---|
616 | png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); |
---|
617 | |
---|
618 | png_ptr->skip_length -= skip_length; |
---|
619 | png_ptr->buffer_size -= save_size; |
---|
620 | png_ptr->current_buffer_size -= save_size; |
---|
621 | png_ptr->current_buffer_ptr += save_size; |
---|
622 | } |
---|
623 | |
---|
624 | if (!png_ptr->skip_length) |
---|
625 | { |
---|
626 | if (png_ptr->buffer_size < 4) |
---|
627 | { |
---|
628 | png_push_save_buffer(png_ptr); |
---|
629 | return; |
---|
630 | } |
---|
631 | |
---|
632 | png_crc_finish(png_ptr, 0); |
---|
633 | png_ptr->process_mode = PNG_READ_CHUNK_MODE; |
---|
634 | } |
---|
635 | } |
---|
636 | |
---|
637 | void PNGCBAPI |
---|
638 | png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length) |
---|
639 | { |
---|
640 | png_bytep ptr; |
---|
641 | |
---|
642 | if (png_ptr == NULL) |
---|
643 | return; |
---|
644 | |
---|
645 | ptr = buffer; |
---|
646 | |
---|
647 | if (png_ptr->save_buffer_size) |
---|
648 | { |
---|
649 | png_size_t save_size; |
---|
650 | |
---|
651 | if (length < png_ptr->save_buffer_size) |
---|
652 | save_size = length; |
---|
653 | |
---|
654 | else |
---|
655 | save_size = png_ptr->save_buffer_size; |
---|
656 | |
---|
657 | png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size); |
---|
658 | length -= save_size; |
---|
659 | ptr += save_size; |
---|
660 | png_ptr->buffer_size -= save_size; |
---|
661 | png_ptr->save_buffer_size -= save_size; |
---|
662 | png_ptr->save_buffer_ptr += save_size; |
---|
663 | } |
---|
664 | |
---|
665 | if (length && png_ptr->current_buffer_size) |
---|
666 | { |
---|
667 | png_size_t save_size; |
---|
668 | |
---|
669 | if (length < png_ptr->current_buffer_size) |
---|
670 | save_size = length; |
---|
671 | |
---|
672 | else |
---|
673 | save_size = png_ptr->current_buffer_size; |
---|
674 | |
---|
675 | png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size); |
---|
676 | png_ptr->buffer_size -= save_size; |
---|
677 | png_ptr->current_buffer_size -= save_size; |
---|
678 | png_ptr->current_buffer_ptr += save_size; |
---|
679 | } |
---|
680 | } |
---|
681 | |
---|
682 | void /* PRIVATE */ |
---|
683 | png_push_save_buffer(png_structp png_ptr) |
---|
684 | { |
---|
685 | if (png_ptr->save_buffer_size) |
---|
686 | { |
---|
687 | if (png_ptr->save_buffer_ptr != png_ptr->save_buffer) |
---|
688 | { |
---|
689 | png_size_t i, istop; |
---|
690 | png_bytep sp; |
---|
691 | png_bytep dp; |
---|
692 | |
---|
693 | istop = png_ptr->save_buffer_size; |
---|
694 | |
---|
695 | for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer; |
---|
696 | i < istop; i++, sp++, dp++) |
---|
697 | { |
---|
698 | *dp = *sp; |
---|
699 | } |
---|
700 | } |
---|
701 | } |
---|
702 | |
---|
703 | if (png_ptr->save_buffer_size + png_ptr->current_buffer_size > |
---|
704 | png_ptr->save_buffer_max) |
---|
705 | { |
---|
706 | png_size_t new_max; |
---|
707 | png_bytep old_buffer; |
---|
708 | |
---|
709 | if (png_ptr->save_buffer_size > PNG_SIZE_MAX - |
---|
710 | (png_ptr->current_buffer_size + 256)) |
---|
711 | { |
---|
712 | png_error(png_ptr, "Potential overflow of save_buffer"); |
---|
713 | } |
---|
714 | |
---|
715 | new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256; |
---|
716 | old_buffer = png_ptr->save_buffer; |
---|
717 | png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, new_max); |
---|
718 | |
---|
719 | if (png_ptr->save_buffer == NULL) |
---|
720 | { |
---|
721 | png_free(png_ptr, old_buffer); |
---|
722 | png_error(png_ptr, "Insufficient memory for save_buffer"); |
---|
723 | } |
---|
724 | |
---|
725 | png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size); |
---|
726 | png_free(png_ptr, old_buffer); |
---|
727 | png_ptr->save_buffer_max = new_max; |
---|
728 | } |
---|
729 | |
---|
730 | if (png_ptr->current_buffer_size) |
---|
731 | { |
---|
732 | png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size, |
---|
733 | png_ptr->current_buffer_ptr, png_ptr->current_buffer_size); |
---|
734 | png_ptr->save_buffer_size += png_ptr->current_buffer_size; |
---|
735 | png_ptr->current_buffer_size = 0; |
---|
736 | } |
---|
737 | |
---|
738 | png_ptr->save_buffer_ptr = png_ptr->save_buffer; |
---|
739 | png_ptr->buffer_size = 0; |
---|
740 | } |
---|
741 | |
---|
742 | void /* PRIVATE */ |
---|
743 | png_push_restore_buffer(png_structp png_ptr, png_bytep buffer, |
---|
744 | png_size_t buffer_length) |
---|
745 | { |
---|
746 | png_ptr->current_buffer = buffer; |
---|
747 | png_ptr->current_buffer_size = buffer_length; |
---|
748 | png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size; |
---|
749 | png_ptr->current_buffer_ptr = png_ptr->current_buffer; |
---|
750 | } |
---|
751 | |
---|
752 | void /* PRIVATE */ |
---|
753 | png_push_read_IDAT(png_structp png_ptr) |
---|
754 | { |
---|
755 | if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER)) |
---|
756 | { |
---|
757 | png_byte chunk_length[4]; |
---|
758 | png_byte chunk_tag[4]; |
---|
759 | |
---|
760 | /* TODO: this code can be commoned up with the same code in push_read */ |
---|
761 | if (png_ptr->buffer_size < 8) |
---|
762 | { |
---|
763 | png_push_save_buffer(png_ptr); |
---|
764 | return; |
---|
765 | } |
---|
766 | |
---|
767 | png_push_fill_buffer(png_ptr, chunk_length, 4); |
---|
768 | png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length); |
---|
769 | png_reset_crc(png_ptr); |
---|
770 | png_crc_read(png_ptr, chunk_tag, 4); |
---|
771 | png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag); |
---|
772 | png_ptr->mode |= PNG_HAVE_CHUNK_HEADER; |
---|
773 | |
---|
774 | if (png_ptr->chunk_name != png_IDAT) |
---|
775 | { |
---|
776 | png_ptr->process_mode = PNG_READ_CHUNK_MODE; |
---|
777 | |
---|
778 | if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED)) |
---|
779 | png_error(png_ptr, "Not enough compressed data"); |
---|
780 | |
---|
781 | return; |
---|
782 | } |
---|
783 | |
---|
784 | png_ptr->idat_size = png_ptr->push_length; |
---|
785 | } |
---|
786 | |
---|
787 | if (png_ptr->idat_size && png_ptr->save_buffer_size) |
---|
788 | { |
---|
789 | png_size_t save_size = png_ptr->save_buffer_size; |
---|
790 | png_uint_32 idat_size = png_ptr->idat_size; |
---|
791 | |
---|
792 | /* We want the smaller of 'idat_size' and 'current_buffer_size', but they |
---|
793 | * are of different types and we don't know which variable has the fewest |
---|
794 | * bits. Carefully select the smaller and cast it to the type of the |
---|
795 | * larger - this cannot overflow. Do not cast in the following test - it |
---|
796 | * will break on either 16 or 64 bit platforms. |
---|
797 | */ |
---|
798 | if (idat_size < save_size) |
---|
799 | save_size = (png_size_t)idat_size; |
---|
800 | |
---|
801 | else |
---|
802 | idat_size = (png_uint_32)save_size; |
---|
803 | |
---|
804 | png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size); |
---|
805 | |
---|
806 | png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size); |
---|
807 | |
---|
808 | png_ptr->idat_size -= idat_size; |
---|
809 | png_ptr->buffer_size -= save_size; |
---|
810 | png_ptr->save_buffer_size -= save_size; |
---|
811 | png_ptr->save_buffer_ptr += save_size; |
---|
812 | } |
---|
813 | |
---|
814 | if (png_ptr->idat_size && png_ptr->current_buffer_size) |
---|
815 | { |
---|
816 | png_size_t save_size = png_ptr->current_buffer_size; |
---|
817 | png_uint_32 idat_size = png_ptr->idat_size; |
---|
818 | |
---|
819 | /* We want the smaller of 'idat_size' and 'current_buffer_size', but they |
---|
820 | * are of different types and we don't know which variable has the fewest |
---|
821 | * bits. Carefully select the smaller and cast it to the type of the |
---|
822 | * larger - this cannot overflow. |
---|
823 | */ |
---|
824 | if (idat_size < save_size) |
---|
825 | save_size = (png_size_t)idat_size; |
---|
826 | |
---|
827 | else |
---|
828 | idat_size = (png_uint_32)save_size; |
---|
829 | |
---|
830 | png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size); |
---|
831 | |
---|
832 | png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size); |
---|
833 | |
---|
834 | png_ptr->idat_size -= idat_size; |
---|
835 | png_ptr->buffer_size -= save_size; |
---|
836 | png_ptr->current_buffer_size -= save_size; |
---|
837 | png_ptr->current_buffer_ptr += save_size; |
---|
838 | } |
---|
839 | |
---|
840 | if (!png_ptr->idat_size) |
---|
841 | { |
---|
842 | if (png_ptr->buffer_size < 4) |
---|
843 | { |
---|
844 | png_push_save_buffer(png_ptr); |
---|
845 | return; |
---|
846 | } |
---|
847 | |
---|
848 | png_crc_finish(png_ptr, 0); |
---|
849 | png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER; |
---|
850 | png_ptr->mode |= PNG_AFTER_IDAT; |
---|
851 | } |
---|
852 | } |
---|
853 | |
---|
854 | void /* PRIVATE */ |
---|
855 | png_process_IDAT_data(png_structp png_ptr, png_bytep buffer, |
---|
856 | png_size_t buffer_length) |
---|
857 | { |
---|
858 | /* The caller checks for a non-zero buffer length. */ |
---|
859 | if (!(buffer_length > 0) || buffer == NULL) |
---|
860 | png_error(png_ptr, "No IDAT data (internal error)"); |
---|
861 | |
---|
862 | /* This routine must process all the data it has been given |
---|
863 | * before returning, calling the row callback as required to |
---|
864 | * handle the uncompressed results. |
---|
865 | */ |
---|
866 | png_ptr->zstream.next_in = buffer; |
---|
867 | png_ptr->zstream.avail_in = (uInt)buffer_length; |
---|
868 | |
---|
869 | /* Keep going until the decompressed data is all processed |
---|
870 | * or the stream marked as finished. |
---|
871 | */ |
---|
872 | while (png_ptr->zstream.avail_in > 0 && |
---|
873 | !(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED)) |
---|
874 | { |
---|
875 | int ret; |
---|
876 | |
---|
877 | /* We have data for zlib, but we must check that zlib |
---|
878 | * has someplace to put the results. It doesn't matter |
---|
879 | * if we don't expect any results -- it may be the input |
---|
880 | * data is just the LZ end code. |
---|
881 | */ |
---|
882 | if (!(png_ptr->zstream.avail_out > 0)) |
---|
883 | { |
---|
884 | png_ptr->zstream.avail_out = |
---|
885 | (uInt) PNG_ROWBYTES(png_ptr->pixel_depth, |
---|
886 | png_ptr->iwidth) + 1; |
---|
887 | |
---|
888 | png_ptr->zstream.next_out = png_ptr->row_buf; |
---|
889 | } |
---|
890 | |
---|
891 | /* Using Z_SYNC_FLUSH here means that an unterminated |
---|
892 | * LZ stream (a stream with a missing end code) can still |
---|
893 | * be handled, otherwise (Z_NO_FLUSH) a future zlib |
---|
894 | * implementation might defer output and therefore |
---|
895 | * change the current behavior (see comments in inflate.c |
---|
896 | * for why this doesn't happen at present with zlib 1.2.5). |
---|
897 | */ |
---|
898 | ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH); |
---|
899 | |
---|
900 | /* Check for any failure before proceeding. */ |
---|
901 | if (ret != Z_OK && ret != Z_STREAM_END) |
---|
902 | { |
---|
903 | /* Terminate the decompression. */ |
---|
904 | png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; |
---|
905 | |
---|
906 | /* This may be a truncated stream (missing or |
---|
907 | * damaged end code). Treat that as a warning. |
---|
908 | */ |
---|
909 | if (png_ptr->row_number >= png_ptr->num_rows || |
---|
910 | png_ptr->pass > 6) |
---|
911 | png_warning(png_ptr, "Truncated compressed data in IDAT"); |
---|
912 | |
---|
913 | else |
---|
914 | png_error(png_ptr, "Decompression error in IDAT"); |
---|
915 | |
---|
916 | /* Skip the check on unprocessed input */ |
---|
917 | return; |
---|
918 | } |
---|
919 | |
---|
920 | /* Did inflate output any data? */ |
---|
921 | if (png_ptr->zstream.next_out != png_ptr->row_buf) |
---|
922 | { |
---|
923 | /* Is this unexpected data after the last row? |
---|
924 | * If it is, artificially terminate the LZ output |
---|
925 | * here. |
---|
926 | */ |
---|
927 | if (png_ptr->row_number >= png_ptr->num_rows || |
---|
928 | png_ptr->pass > 6) |
---|
929 | { |
---|
930 | /* Extra data. */ |
---|
931 | png_warning(png_ptr, "Extra compressed data in IDAT"); |
---|
932 | png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; |
---|
933 | |
---|
934 | /* Do no more processing; skip the unprocessed |
---|
935 | * input check below. |
---|
936 | */ |
---|
937 | return; |
---|
938 | } |
---|
939 | |
---|
940 | /* Do we have a complete row? */ |
---|
941 | if (png_ptr->zstream.avail_out == 0) |
---|
942 | png_push_process_row(png_ptr); |
---|
943 | } |
---|
944 | |
---|
945 | /* And check for the end of the stream. */ |
---|
946 | if (ret == Z_STREAM_END) |
---|
947 | png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED; |
---|
948 | } |
---|
949 | |
---|
950 | /* All the data should have been processed, if anything |
---|
951 | * is left at this point we have bytes of IDAT data |
---|
952 | * after the zlib end code. |
---|
953 | */ |
---|
954 | if (png_ptr->zstream.avail_in > 0) |
---|
955 | png_warning(png_ptr, "Extra compression data in IDAT"); |
---|
956 | } |
---|
957 | |
---|
958 | void /* PRIVATE */ |
---|
959 | png_push_process_row(png_structp png_ptr) |
---|
960 | { |
---|
961 | /* 1.5.6: row_info moved out of png_struct to a local here. */ |
---|
962 | png_row_info row_info; |
---|
963 | |
---|
964 | row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */ |
---|
965 | row_info.color_type = png_ptr->color_type; |
---|
966 | row_info.bit_depth = png_ptr->bit_depth; |
---|
967 | row_info.channels = png_ptr->channels; |
---|
968 | row_info.pixel_depth = png_ptr->pixel_depth; |
---|
969 | row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width); |
---|
970 | |
---|
971 | if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE) |
---|
972 | { |
---|
973 | if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST) |
---|
974 | png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1, |
---|
975 | png_ptr->prev_row + 1, png_ptr->row_buf[0]); |
---|
976 | else |
---|
977 | png_error(png_ptr, "bad adaptive filter value"); |
---|
978 | } |
---|
979 | |
---|
980 | /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before |
---|
981 | * 1.5.6, while the buffer really is this big in current versions of libpng |
---|
982 | * it may not be in the future, so this was changed just to copy the |
---|
983 | * interlaced row count: |
---|
984 | */ |
---|
985 | png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1); |
---|
986 | |
---|
987 | #ifdef PNG_READ_TRANSFORMS_SUPPORTED |
---|
988 | if (png_ptr->transformations) |
---|
989 | png_do_read_transformations(png_ptr, &row_info); |
---|
990 | #endif |
---|
991 | |
---|
992 | /* The transformed pixel depth should match the depth now in row_info. */ |
---|
993 | if (png_ptr->transformed_pixel_depth == 0) |
---|
994 | { |
---|
995 | png_ptr->transformed_pixel_depth = row_info.pixel_depth; |
---|
996 | if (row_info.pixel_depth > png_ptr->maximum_pixel_depth) |
---|
997 | png_error(png_ptr, "progressive row overflow"); |
---|
998 | } |
---|
999 | |
---|
1000 | else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth) |
---|
1001 | png_error(png_ptr, "internal progressive row size calculation error"); |
---|
1002 | |
---|
1003 | |
---|
1004 | #ifdef PNG_READ_INTERLACING_SUPPORTED |
---|
1005 | /* Blow up interlaced rows to full size */ |
---|
1006 | if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE)) |
---|
1007 | { |
---|
1008 | if (png_ptr->pass < 6) |
---|
1009 | png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass, |
---|
1010 | png_ptr->transformations); |
---|
1011 | |
---|
1012 | switch (png_ptr->pass) |
---|
1013 | { |
---|
1014 | case 0: |
---|
1015 | { |
---|
1016 | int i; |
---|
1017 | for (i = 0; i < 8 && png_ptr->pass == 0; i++) |
---|
1018 | { |
---|
1019 | png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
---|
1020 | png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */ |
---|
1021 | } |
---|
1022 | |
---|
1023 | if (png_ptr->pass == 2) /* Pass 1 might be empty */ |
---|
1024 | { |
---|
1025 | for (i = 0; i < 4 && png_ptr->pass == 2; i++) |
---|
1026 | { |
---|
1027 | png_push_have_row(png_ptr, NULL); |
---|
1028 | png_read_push_finish_row(png_ptr); |
---|
1029 | } |
---|
1030 | } |
---|
1031 | |
---|
1032 | if (png_ptr->pass == 4 && png_ptr->height <= 4) |
---|
1033 | { |
---|
1034 | for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
---|
1035 | { |
---|
1036 | png_push_have_row(png_ptr, NULL); |
---|
1037 | png_read_push_finish_row(png_ptr); |
---|
1038 | } |
---|
1039 | } |
---|
1040 | |
---|
1041 | if (png_ptr->pass == 6 && png_ptr->height <= 4) |
---|
1042 | { |
---|
1043 | png_push_have_row(png_ptr, NULL); |
---|
1044 | png_read_push_finish_row(png_ptr); |
---|
1045 | } |
---|
1046 | |
---|
1047 | break; |
---|
1048 | } |
---|
1049 | |
---|
1050 | case 1: |
---|
1051 | { |
---|
1052 | int i; |
---|
1053 | for (i = 0; i < 8 && png_ptr->pass == 1; i++) |
---|
1054 | { |
---|
1055 | png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
---|
1056 | png_read_push_finish_row(png_ptr); |
---|
1057 | } |
---|
1058 | |
---|
1059 | if (png_ptr->pass == 2) /* Skip top 4 generated rows */ |
---|
1060 | { |
---|
1061 | for (i = 0; i < 4 && png_ptr->pass == 2; i++) |
---|
1062 | { |
---|
1063 | png_push_have_row(png_ptr, NULL); |
---|
1064 | png_read_push_finish_row(png_ptr); |
---|
1065 | } |
---|
1066 | } |
---|
1067 | |
---|
1068 | break; |
---|
1069 | } |
---|
1070 | |
---|
1071 | case 2: |
---|
1072 | { |
---|
1073 | int i; |
---|
1074 | |
---|
1075 | for (i = 0; i < 4 && png_ptr->pass == 2; i++) |
---|
1076 | { |
---|
1077 | png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
---|
1078 | png_read_push_finish_row(png_ptr); |
---|
1079 | } |
---|
1080 | |
---|
1081 | for (i = 0; i < 4 && png_ptr->pass == 2; i++) |
---|
1082 | { |
---|
1083 | png_push_have_row(png_ptr, NULL); |
---|
1084 | png_read_push_finish_row(png_ptr); |
---|
1085 | } |
---|
1086 | |
---|
1087 | if (png_ptr->pass == 4) /* Pass 3 might be empty */ |
---|
1088 | { |
---|
1089 | for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
---|
1090 | { |
---|
1091 | png_push_have_row(png_ptr, NULL); |
---|
1092 | png_read_push_finish_row(png_ptr); |
---|
1093 | } |
---|
1094 | } |
---|
1095 | |
---|
1096 | break; |
---|
1097 | } |
---|
1098 | |
---|
1099 | case 3: |
---|
1100 | { |
---|
1101 | int i; |
---|
1102 | |
---|
1103 | for (i = 0; i < 4 && png_ptr->pass == 3; i++) |
---|
1104 | { |
---|
1105 | png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
---|
1106 | png_read_push_finish_row(png_ptr); |
---|
1107 | } |
---|
1108 | |
---|
1109 | if (png_ptr->pass == 4) /* Skip top two generated rows */ |
---|
1110 | { |
---|
1111 | for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
---|
1112 | { |
---|
1113 | png_push_have_row(png_ptr, NULL); |
---|
1114 | png_read_push_finish_row(png_ptr); |
---|
1115 | } |
---|
1116 | } |
---|
1117 | |
---|
1118 | break; |
---|
1119 | } |
---|
1120 | |
---|
1121 | case 4: |
---|
1122 | { |
---|
1123 | int i; |
---|
1124 | |
---|
1125 | for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
---|
1126 | { |
---|
1127 | png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
---|
1128 | png_read_push_finish_row(png_ptr); |
---|
1129 | } |
---|
1130 | |
---|
1131 | for (i = 0; i < 2 && png_ptr->pass == 4; i++) |
---|
1132 | { |
---|
1133 | png_push_have_row(png_ptr, NULL); |
---|
1134 | png_read_push_finish_row(png_ptr); |
---|
1135 | } |
---|
1136 | |
---|
1137 | if (png_ptr->pass == 6) /* Pass 5 might be empty */ |
---|
1138 | { |
---|
1139 | png_push_have_row(png_ptr, NULL); |
---|
1140 | png_read_push_finish_row(png_ptr); |
---|
1141 | } |
---|
1142 | |
---|
1143 | break; |
---|
1144 | } |
---|
1145 | |
---|
1146 | case 5: |
---|
1147 | { |
---|
1148 | int i; |
---|
1149 | |
---|
1150 | for (i = 0; i < 2 && png_ptr->pass == 5; i++) |
---|
1151 | { |
---|
1152 | png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
---|
1153 | png_read_push_finish_row(png_ptr); |
---|
1154 | } |
---|
1155 | |
---|
1156 | if (png_ptr->pass == 6) /* Skip top generated row */ |
---|
1157 | { |
---|
1158 | png_push_have_row(png_ptr, NULL); |
---|
1159 | png_read_push_finish_row(png_ptr); |
---|
1160 | } |
---|
1161 | |
---|
1162 | break; |
---|
1163 | } |
---|
1164 | |
---|
1165 | default: |
---|
1166 | case 6: |
---|
1167 | { |
---|
1168 | png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
---|
1169 | png_read_push_finish_row(png_ptr); |
---|
1170 | |
---|
1171 | if (png_ptr->pass != 6) |
---|
1172 | break; |
---|
1173 | |
---|
1174 | png_push_have_row(png_ptr, NULL); |
---|
1175 | png_read_push_finish_row(png_ptr); |
---|
1176 | } |
---|
1177 | } |
---|
1178 | } |
---|
1179 | else |
---|
1180 | #endif |
---|
1181 | { |
---|
1182 | png_push_have_row(png_ptr, png_ptr->row_buf + 1); |
---|
1183 | png_read_push_finish_row(png_ptr); |
---|
1184 | } |
---|
1185 | } |
---|
1186 | |
---|
1187 | void /* PRIVATE */ |
---|
1188 | png_read_push_finish_row(png_structp png_ptr) |
---|
1189 | { |
---|
1190 | #ifdef PNG_READ_INTERLACING_SUPPORTED |
---|
1191 | /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ |
---|
1192 | |
---|
1193 | /* Start of interlace block */ |
---|
1194 | static PNG_CONST png_byte FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; |
---|
1195 | |
---|
1196 | /* Offset to next interlace block */ |
---|
1197 | static PNG_CONST png_byte FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; |
---|
1198 | |
---|
1199 | /* Start of interlace block in the y direction */ |
---|
1200 | static PNG_CONST png_byte FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; |
---|
1201 | |
---|
1202 | /* Offset to next interlace block in the y direction */ |
---|
1203 | static PNG_CONST png_byte FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2}; |
---|
1204 | |
---|
1205 | /* Height of interlace block. This is not currently used - if you need |
---|
1206 | * it, uncomment it here and in png.h |
---|
1207 | static PNG_CONST png_byte FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1}; |
---|
1208 | */ |
---|
1209 | #endif |
---|
1210 | |
---|
1211 | png_ptr->row_number++; |
---|
1212 | if (png_ptr->row_number < png_ptr->num_rows) |
---|
1213 | return; |
---|
1214 | |
---|
1215 | #ifdef PNG_READ_INTERLACING_SUPPORTED |
---|
1216 | if (png_ptr->interlaced) |
---|
1217 | { |
---|
1218 | png_ptr->row_number = 0; |
---|
1219 | png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1); |
---|
1220 | |
---|
1221 | do |
---|
1222 | { |
---|
1223 | png_ptr->pass++; |
---|
1224 | if ((png_ptr->pass == 1 && png_ptr->width < 5) || |
---|
1225 | (png_ptr->pass == 3 && png_ptr->width < 3) || |
---|
1226 | (png_ptr->pass == 5 && png_ptr->width < 2)) |
---|
1227 | png_ptr->pass++; |
---|
1228 | |
---|
1229 | if (png_ptr->pass > 7) |
---|
1230 | png_ptr->pass--; |
---|
1231 | |
---|
1232 | if (png_ptr->pass >= 7) |
---|
1233 | break; |
---|
1234 | |
---|
1235 | png_ptr->iwidth = (png_ptr->width + |
---|
1236 | png_pass_inc[png_ptr->pass] - 1 - |
---|
1237 | png_pass_start[png_ptr->pass]) / |
---|
1238 | png_pass_inc[png_ptr->pass]; |
---|
1239 | |
---|
1240 | if (png_ptr->transformations & PNG_INTERLACE) |
---|
1241 | break; |
---|
1242 | |
---|
1243 | png_ptr->num_rows = (png_ptr->height + |
---|
1244 | png_pass_yinc[png_ptr->pass] - 1 - |
---|
1245 | png_pass_ystart[png_ptr->pass]) / |
---|
1246 | png_pass_yinc[png_ptr->pass]; |
---|
1247 | |
---|
1248 | } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0); |
---|
1249 | } |
---|
1250 | #endif /* PNG_READ_INTERLACING_SUPPORTED */ |
---|
1251 | } |
---|
1252 | |
---|
1253 | void /* PRIVATE */ |
---|
1254 | png_push_have_info(png_structp png_ptr, png_infop info_ptr) |
---|
1255 | { |
---|
1256 | if (png_ptr->info_fn != NULL) |
---|
1257 | (*(png_ptr->info_fn))(png_ptr, info_ptr); |
---|
1258 | } |
---|
1259 | |
---|
1260 | void /* PRIVATE */ |
---|
1261 | png_push_have_end(png_structp png_ptr, png_infop info_ptr) |
---|
1262 | { |
---|
1263 | if (png_ptr->end_fn != NULL) |
---|
1264 | (*(png_ptr->end_fn))(png_ptr, info_ptr); |
---|
1265 | } |
---|
1266 | |
---|
1267 | void /* PRIVATE */ |
---|
1268 | png_push_have_row(png_structp png_ptr, png_bytep row) |
---|
1269 | { |
---|
1270 | if (png_ptr->row_fn != NULL) |
---|
1271 | (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number, |
---|
1272 | (int)png_ptr->pass); |
---|
1273 | } |
---|
1274 | |
---|
1275 | #ifdef PNG_READ_INTERLACING_SUPPORTED |
---|
1276 | void PNGAPI |
---|
1277 | png_progressive_combine_row (png_structp png_ptr, png_bytep old_row, |
---|
1278 | png_const_bytep new_row) |
---|
1279 | { |
---|
1280 | if (png_ptr == NULL) |
---|
1281 | return; |
---|
1282 | |
---|
1283 | /* new_row is a flag here - if it is NULL then the app callback was called |
---|
1284 | * from an empty row (see the calls to png_struct::row_fn below), otherwise |
---|
1285 | * it must be png_ptr->row_buf+1 |
---|
1286 | */ |
---|
1287 | if (new_row != NULL) |
---|
1288 | png_combine_row(png_ptr, old_row, 1/*display*/); |
---|
1289 | } |
---|
1290 | #endif /* PNG_READ_INTERLACING_SUPPORTED */ |
---|
1291 | |
---|
1292 | void PNGAPI |
---|
1293 | png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr, |
---|
1294 | png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn, |
---|
1295 | png_progressive_end_ptr end_fn) |
---|
1296 | { |
---|
1297 | if (png_ptr == NULL) |
---|
1298 | return; |
---|
1299 | |
---|
1300 | png_ptr->info_fn = info_fn; |
---|
1301 | png_ptr->row_fn = row_fn; |
---|
1302 | png_ptr->end_fn = end_fn; |
---|
1303 | |
---|
1304 | png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer); |
---|
1305 | } |
---|
1306 | |
---|
1307 | png_voidp PNGAPI |
---|
1308 | png_get_progressive_ptr(png_const_structp png_ptr) |
---|
1309 | { |
---|
1310 | if (png_ptr == NULL) |
---|
1311 | return (NULL); |
---|
1312 | |
---|
1313 | return png_ptr->io_ptr; |
---|
1314 | } |
---|
1315 | #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */ |
---|