1 /* |
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2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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3 * |
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4 * This code is free software; you can redistribute it and/or modify it |
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5 * under the terms of the GNU General Public License version 2 only, as |
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6 * published by the Free Software Foundation. Oracle designates this |
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7 * particular file as subject to the "Classpath" exception as provided |
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8 * by Oracle in the LICENSE file that accompanied this code. |
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9 * |
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10 * This code is distributed in the hope that it will be useful, but WITHOUT |
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11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 * version 2 for more details (a copy is included in the LICENSE file that |
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14 * accompanied this code). |
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15 * |
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16 * You should have received a copy of the GNU General Public License version |
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17 * 2 along with this work; if not, write to the Free Software Foundation, |
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18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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19 * |
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20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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21 * or visit www.oracle.com if you need additional information or have any |
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22 * questions. |
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23 */ |
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24 |
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25 /* pngwio.c - functions for data output |
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26 * |
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27 * This file is available under and governed by the GNU General Public |
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28 * License version 2 only, as published by the Free Software Foundation. |
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29 * However, the following notice accompanied the original version of this |
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30 * file and, per its terms, should not be removed: |
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31 * |
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32 * Last changed in libpng 1.6.15 [November 20, 2014] |
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33 * Copyright (c) 1998-2002,2004,2006-2014 Glenn Randers-Pehrson |
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34 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
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35 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
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36 * |
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37 * This code is released under the libpng license. |
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38 * For conditions of distribution and use, see the disclaimer |
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39 * and license in png.h |
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40 * |
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41 * This file provides a location for all output. Users who need |
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42 * special handling are expected to write functions that have the same |
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43 * arguments as these and perform similar functions, but that possibly |
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44 * use different output methods. Note that you shouldn't change these |
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45 * functions, but rather write replacement functions and then change |
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46 * them at run time with png_set_write_fn(...). |
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47 */ |
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48 |
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49 #include "pngpriv.h" |
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50 |
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51 #ifdef PNG_WRITE_SUPPORTED |
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52 |
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53 /* Write the data to whatever output you are using. The default routine |
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54 * writes to a file pointer. Note that this routine sometimes gets called |
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55 * with very small lengths, so you should implement some kind of simple |
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56 * buffering if you are using unbuffered writes. This should never be asked |
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57 * to write more than 64K on a 16-bit machine. |
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58 */ |
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59 |
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60 void /* PRIVATE */ |
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61 png_write_data(png_structrp png_ptr, png_const_bytep data, png_size_t length) |
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62 { |
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63 /* NOTE: write_data_fn must not change the buffer! */ |
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64 if (png_ptr->write_data_fn != NULL ) |
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65 (*(png_ptr->write_data_fn))(png_ptr, png_constcast(png_bytep,data), |
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66 length); |
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67 |
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68 else |
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69 png_error(png_ptr, "Call to NULL write function"); |
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70 } |
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71 |
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72 #ifdef PNG_STDIO_SUPPORTED |
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73 /* This is the function that does the actual writing of data. If you are |
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74 * not writing to a standard C stream, you should create a replacement |
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75 * write_data function and use it at run time with png_set_write_fn(), rather |
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76 * than changing the library. |
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77 */ |
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78 void PNGCBAPI |
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79 png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length) |
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80 { |
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81 png_size_t check; |
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82 |
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83 if (png_ptr == NULL) |
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84 return; |
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85 |
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86 check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr)); |
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87 |
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88 if (check != length) |
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89 png_error(png_ptr, "Write Error"); |
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90 } |
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91 #endif |
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92 |
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93 /* This function is called to output any data pending writing (normally |
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94 * to disk). After png_flush is called, there should be no data pending |
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95 * writing in any buffers. |
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96 */ |
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97 #ifdef PNG_WRITE_FLUSH_SUPPORTED |
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98 void /* PRIVATE */ |
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99 png_flush(png_structrp png_ptr) |
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100 { |
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101 if (png_ptr->output_flush_fn != NULL) |
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102 (*(png_ptr->output_flush_fn))(png_ptr); |
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103 } |
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104 |
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105 # ifdef PNG_STDIO_SUPPORTED |
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106 void PNGCBAPI |
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107 png_default_flush(png_structp png_ptr) |
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108 { |
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109 png_FILE_p io_ptr; |
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110 |
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111 if (png_ptr == NULL) |
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112 return; |
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113 |
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114 io_ptr = png_voidcast(png_FILE_p, (png_ptr->io_ptr)); |
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115 fflush(io_ptr); |
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116 } |
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117 # endif |
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118 #endif |
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119 |
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120 /* This function allows the application to supply new output functions for |
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121 * libpng if standard C streams aren't being used. |
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122 * |
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123 * This function takes as its arguments: |
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124 * png_ptr - pointer to a png output data structure |
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125 * io_ptr - pointer to user supplied structure containing info about |
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126 * the output functions. May be NULL. |
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127 * write_data_fn - pointer to a new output function that takes as its |
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128 * arguments a pointer to a png_struct, a pointer to |
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129 * data to be written, and a 32-bit unsigned int that is |
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130 * the number of bytes to be written. The new write |
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131 * function should call png_error(png_ptr, "Error msg") |
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132 * to exit and output any fatal error messages. May be |
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133 * NULL, in which case libpng's default function will |
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134 * be used. |
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135 * flush_data_fn - pointer to a new flush function that takes as its |
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136 * arguments a pointer to a png_struct. After a call to |
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137 * the flush function, there should be no data in any buffers |
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138 * or pending transmission. If the output method doesn't do |
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139 * any buffering of output, a function prototype must still be |
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140 * supplied although it doesn't have to do anything. If |
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141 * PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile |
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142 * time, output_flush_fn will be ignored, although it must be |
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143 * supplied for compatibility. May be NULL, in which case |
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144 * libpng's default function will be used, if |
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145 * PNG_WRITE_FLUSH_SUPPORTED is defined. This is not |
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146 * a good idea if io_ptr does not point to a standard |
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147 * *FILE structure. |
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148 */ |
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149 void PNGAPI |
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150 png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr, |
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151 png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn) |
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152 { |
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153 if (png_ptr == NULL) |
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154 return; |
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155 |
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156 png_ptr->io_ptr = io_ptr; |
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157 |
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158 #ifdef PNG_STDIO_SUPPORTED |
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159 if (write_data_fn != NULL) |
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160 png_ptr->write_data_fn = write_data_fn; |
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161 |
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162 else |
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163 png_ptr->write_data_fn = png_default_write_data; |
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164 #else |
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165 png_ptr->write_data_fn = write_data_fn; |
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166 #endif |
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167 |
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168 #ifdef PNG_WRITE_FLUSH_SUPPORTED |
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169 # ifdef PNG_STDIO_SUPPORTED |
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170 |
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171 if (output_flush_fn != NULL) |
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172 png_ptr->output_flush_fn = output_flush_fn; |
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173 |
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174 else |
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175 png_ptr->output_flush_fn = png_default_flush; |
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176 |
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177 # else |
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178 png_ptr->output_flush_fn = output_flush_fn; |
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179 # endif |
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180 #else |
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181 PNG_UNUSED(output_flush_fn) |
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182 #endif /* WRITE_FLUSH */ |
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183 |
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184 #ifdef PNG_READ_SUPPORTED |
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185 /* It is an error to read while writing a png file */ |
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186 if (png_ptr->read_data_fn != NULL) |
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187 { |
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188 png_ptr->read_data_fn = NULL; |
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189 |
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190 png_warning(png_ptr, |
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191 "Can't set both read_data_fn and write_data_fn in the" |
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192 " same structure"); |
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193 } |
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194 #endif |
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195 } |
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196 #endif /* WRITE */ |
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