2 /* pngwutil.c - utilities to write a PNG file
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4 * Last changed in libpng 1.6.2 [April 25, 2013]
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5 * Copyright (c) 1998-2013 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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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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13 #if (!defined(_FPDFAPI_MINI_) || defined(_FXCORE_FEATURE_ALL_) || defined(_PNG_DECODER_)) && !defined(_USE_ADDIN_) && !defined(_FX_EMB_NOUSE_DECODER_)
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14 #include "pngpriv.h"
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16 #ifdef PNG_WRITE_SUPPORTED
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18 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
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19 /* Place a 32-bit number into a buffer in PNG byte order. We work
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20 * with unsigned numbers for convenience, although one supported
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21 * ancillary chunk uses signed (two's complement) numbers.
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24 png_save_uint_32(png_bytep buf, png_uint_32 i)
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26 buf[0] = (png_byte)((i >> 24) & 0xff);
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27 buf[1] = (png_byte)((i >> 16) & 0xff);
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28 buf[2] = (png_byte)((i >> 8) & 0xff);
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29 buf[3] = (png_byte)(i & 0xff);
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32 /* Place a 16-bit number into a buffer in PNG byte order.
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33 * The parameter is declared unsigned int, not png_uint_16,
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34 * just to avoid potential problems on pre-ANSI C compilers.
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37 png_save_uint_16(png_bytep buf, unsigned int i)
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39 buf[0] = (png_byte)((i >> 8) & 0xff);
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40 buf[1] = (png_byte)(i & 0xff);
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44 /* Simple function to write the signature. If we have already written
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45 * the magic bytes of the signature, or more likely, the PNG stream is
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46 * being embedded into another stream and doesn't need its own signature,
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47 * we should call png_set_sig_bytes() to tell libpng how many of the
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48 * bytes have already been written.
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51 png_write_sig(png_structrp png_ptr)
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53 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
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55 #ifdef PNG_IO_STATE_SUPPORTED
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56 /* Inform the I/O callback that the signature is being written */
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57 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
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60 /* Write the rest of the 8 byte signature */
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61 png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
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62 (png_size_t)(8 - png_ptr->sig_bytes));
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64 if (png_ptr->sig_bytes < 3)
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65 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
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68 /* Write the start of a PNG chunk. The type is the chunk type.
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69 * The total_length is the sum of the lengths of all the data you will be
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70 * passing in png_write_chunk_data().
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73 png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name,
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78 #if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
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79 PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
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80 png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
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83 if (png_ptr == NULL)
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86 #ifdef PNG_IO_STATE_SUPPORTED
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87 /* Inform the I/O callback that the chunk header is being written.
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88 * PNG_IO_CHUNK_HDR requires a single I/O call.
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90 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
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93 /* Write the length and the chunk name */
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94 png_save_uint_32(buf, length);
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95 png_save_uint_32(buf + 4, chunk_name);
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96 png_write_data(png_ptr, buf, 8);
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98 /* Put the chunk name into png_ptr->chunk_name */
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99 png_ptr->chunk_name = chunk_name;
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101 /* Reset the crc and run it over the chunk name */
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102 png_reset_crc(png_ptr);
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104 png_calculate_crc(png_ptr, buf + 4, 4);
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106 #ifdef PNG_IO_STATE_SUPPORTED
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107 /* Inform the I/O callback that chunk data will (possibly) be written.
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108 * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
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110 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
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115 png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string,
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116 png_uint_32 length)
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118 png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
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121 /* Write the data of a PNG chunk started with png_write_chunk_header().
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122 * Note that multiple calls to this function are allowed, and that the
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123 * sum of the lengths from these calls *must* add up to the total_length
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124 * given to png_write_chunk_header().
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127 png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
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130 /* Write the data, and run the CRC over it */
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131 if (png_ptr == NULL)
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134 if (data != NULL && length > 0)
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136 png_write_data(png_ptr, data, length);
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138 /* Update the CRC after writing the data,
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139 * in case that the user I/O routine alters it.
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141 png_calculate_crc(png_ptr, data, length);
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145 /* Finish a chunk started with png_write_chunk_header(). */
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147 png_write_chunk_end(png_structrp png_ptr)
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151 if (png_ptr == NULL) return;
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153 #ifdef PNG_IO_STATE_SUPPORTED
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154 /* Inform the I/O callback that the chunk CRC is being written.
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155 * PNG_IO_CHUNK_CRC requires a single I/O function call.
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157 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
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160 /* Write the crc in a single operation */
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161 png_save_uint_32(buf, png_ptr->crc);
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163 png_write_data(png_ptr, buf, (png_size_t)4);
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166 /* Write a PNG chunk all at once. The type is an array of ASCII characters
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167 * representing the chunk name. The array must be at least 4 bytes in
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168 * length, and does not need to be null terminated. To be safe, pass the
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169 * pre-defined chunk names here, and if you need a new one, define it
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170 * where the others are defined. The length is the length of the data.
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171 * All the data must be present. If that is not possible, use the
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172 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
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173 * functions instead.
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176 png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
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177 png_const_bytep data, png_size_t length)
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179 if (png_ptr == NULL)
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182 /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
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183 if (length > PNG_UINT_31_MAX)
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184 png_error(png_ptr, "length exceeds PNG maxima");
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186 png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
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187 png_write_chunk_data(png_ptr, data, length);
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188 png_write_chunk_end(png_ptr);
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191 /* This is the API that calls the internal function above. */
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193 png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
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194 png_const_bytep data, png_size_t length)
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196 png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
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200 /* This is used below to find the size of an image to pass to png_deflate_claim,
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201 * so it only needs to be accurate if the size is less than 16384 bytes (the
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202 * point at which a lower LZ window size can be used.)
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204 static png_alloc_size_t
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205 png_image_size(png_structrp png_ptr)
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207 /* Only return sizes up to the maximum of a png_uint_32, do this by limiting
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208 * the width and height used to 15 bits.
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210 png_uint_32 h = png_ptr->height;
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212 if (png_ptr->rowbytes < 32768 && h < 32768)
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214 if (png_ptr->interlaced)
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216 /* Interlacing makes the image larger because of the replication of
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217 * both the filter byte and the padding to a byte boundary.
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219 png_uint_32 w = png_ptr->width;
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220 unsigned int pd = png_ptr->pixel_depth;
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221 png_alloc_size_t cb_base;
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224 for (cb_base=0, pass=0; pass<=6; ++pass)
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226 png_uint_32 pw = PNG_PASS_COLS(w, pass);
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229 cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);
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236 return (png_ptr->rowbytes+1) * h;
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240 return 0xffffffffU;
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243 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
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244 /* This is the code to hack the first two bytes of the deflate stream (the
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245 * deflate header) to correct the windowBits value to match the actual data
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246 * size. Note that the second argument is the *uncompressed* size but the
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247 * first argument is the *compressed* data (and it must be deflate
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251 optimize_cmf(png_bytep data, png_alloc_size_t data_size)
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253 /* Optimize the CMF field in the zlib stream. The resultant zlib stream is
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254 * still compliant to the stream specification.
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256 if (data_size <= 16384) /* else windowBits must be 15 */
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258 unsigned int z_cmf = data[0]; /* zlib compression method and flags */
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260 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
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262 unsigned int z_cinfo;
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263 unsigned int half_z_window_size;
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265 z_cinfo = z_cmf >> 4;
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266 half_z_window_size = 1U << (z_cinfo + 7);
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268 if (data_size <= half_z_window_size) /* else no change */
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274 half_z_window_size >>= 1;
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277 while (z_cinfo > 0 && data_size <= half_z_window_size);
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279 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
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281 data[0] = (png_byte)z_cmf;
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282 tmp = data[1] & 0xe0;
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283 tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
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284 data[1] = (png_byte)tmp;
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290 # define optimize_cmf(dp,dl) ((void)0)
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291 #endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
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293 /* Initialize the compressor for the appropriate type of compression. */
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295 png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
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296 png_alloc_size_t data_size)
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298 if (png_ptr->zowner != 0)
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302 PNG_STRING_FROM_CHUNK(msg, owner);
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305 PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);
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306 /* So the message that results is "<chunk> using zstream"; this is an
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307 * internal error, but is very useful for debugging. i18n requirements
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310 (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
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311 # if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
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312 png_warning(png_ptr, msg);
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314 /* Attempt sane error recovery */
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315 if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */
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317 png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");
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318 return Z_STREAM_ERROR;
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321 png_ptr->zowner = 0;
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323 png_error(png_ptr, msg);
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328 int level = png_ptr->zlib_level;
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329 int method = png_ptr->zlib_method;
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330 int windowBits = png_ptr->zlib_window_bits;
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331 int memLevel = png_ptr->zlib_mem_level;
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332 int strategy; /* set below */
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333 int ret; /* zlib return code */
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335 if (owner == png_IDAT)
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337 if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)
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338 strategy = png_ptr->zlib_strategy;
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340 else if (png_ptr->do_filter != PNG_FILTER_NONE)
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341 strategy = PNG_Z_DEFAULT_STRATEGY;
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344 strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;
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349 # ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
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350 level = png_ptr->zlib_text_level;
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351 method = png_ptr->zlib_text_method;
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352 windowBits = png_ptr->zlib_text_window_bits;
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353 memLevel = png_ptr->zlib_text_mem_level;
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354 strategy = png_ptr->zlib_text_strategy;
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356 /* If customization is not supported the values all come from the
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357 * IDAT values except for the strategy, which is fixed to the
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358 * default. (This is the pre-1.6.0 behavior too, although it was
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359 * implemented in a very different way.)
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361 strategy = Z_DEFAULT_STRATEGY;
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365 /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
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366 * happening just pass 32768 as the data_size parameter. Notice that zlib
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367 * requires an extra 262 bytes in the window in addition to the data to be
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368 * able to see the whole of the data, so if data_size+262 takes us to the
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369 * next windowBits size we need to fix up the value later. (Because even
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370 * though deflate needs the extra window, inflate does not!)
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372 if (data_size <= 16384)
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374 /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to
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375 * work round a Microsoft Visual C misbehavior which, contrary to C-90,
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376 * widens the result of the following shift to 64-bits if (and,
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377 * apparently, only if) it is used in a test.
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379 unsigned int half_window_size = 1U << (windowBits-1);
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381 while (data_size + 262 <= half_window_size)
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383 half_window_size >>= 1;
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388 /* Check against the previous initialized values, if any. */
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389 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) &&
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390 (png_ptr->zlib_set_level != level ||
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391 png_ptr->zlib_set_method != method ||
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392 png_ptr->zlib_set_window_bits != windowBits ||
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393 png_ptr->zlib_set_mem_level != memLevel ||
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394 png_ptr->zlib_set_strategy != strategy))
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396 if (deflateEnd(&png_ptr->zstream) != Z_OK)
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397 png_warning(png_ptr, "deflateEnd failed (ignored)");
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399 png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;
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402 /* For safety clear out the input and output pointers (currently zlib
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403 * doesn't use them on Init, but it might in the future).
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405 png_ptr->zstream.next_in = NULL;
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406 png_ptr->zstream.avail_in = 0;
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407 png_ptr->zstream.next_out = NULL;
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408 png_ptr->zstream.avail_out = 0;
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410 /* Now initialize if required, setting the new parameters, otherwise just
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411 * to a simple reset to the previous parameters.
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413 if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
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414 ret = deflateReset(&png_ptr->zstream);
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418 ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
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419 memLevel, strategy);
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422 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
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425 /* The return code is from either deflateReset or deflateInit2; they have
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426 * pretty much the same set of error codes.
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429 png_ptr->zowner = owner;
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432 png_zstream_error(png_ptr, ret);
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438 /* Clean up (or trim) a linked list of compression buffers. */
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440 png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)
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442 png_compression_bufferp list = *listp;
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450 png_compression_bufferp next = list->next;
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452 png_free(png_ptr, list);
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455 while (list != NULL);
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459 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
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460 /* This pair of functions encapsulates the operation of (a) compressing a
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461 * text string, and (b) issuing it later as a series of chunk data writes.
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462 * The compression_state structure is shared context for these functions
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463 * set up by the caller to allow access to the relevant local variables.
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465 * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size
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466 * temporary buffers. From 1.6.0 it is retained in png_struct so that it will
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467 * be correctly freed in the event of a write error (previous implementations
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468 * just leaked memory.)
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472 png_const_bytep input; /* The uncompressed input data */
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473 png_alloc_size_t input_len; /* Its length */
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474 png_uint_32 output_len; /* Final compressed length */
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475 png_byte output[1024]; /* First block of output */
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476 } compression_state;
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479 png_text_compress_init(compression_state *comp, png_const_bytep input,
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480 png_alloc_size_t input_len)
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482 comp->input = input;
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483 comp->input_len = input_len;
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484 comp->output_len = 0;
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487 /* Compress the data in the compression state input */
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489 png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
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490 compression_state *comp, png_uint_32 prefix_len)
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494 /* To find the length of the output it is necessary to first compress the
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495 * input, the result is buffered rather than using the two-pass algorithm
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496 * that is used on the inflate side; deflate is assumed to be slower and a
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497 * PNG writer is assumed to have more memory available than a PNG reader.
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499 * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an
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500 * upper limit on the output size, but it is always bigger than the input
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501 * size so it is likely to be more efficient to use this linked-list
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504 ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);
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509 /* Set up the compression buffers, we need a loop here to avoid overflowing a
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510 * uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited
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511 * by the output buffer size, so there is no need to check that. Since this
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512 * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits
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516 png_compression_bufferp *end = &png_ptr->zbuffer_list;
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517 png_alloc_size_t input_len = comp->input_len; /* may be zero! */
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518 png_uint_32 output_len;
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520 /* zlib updates these for us: */
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521 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);
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522 png_ptr->zstream.avail_in = 0; /* Set below */
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523 png_ptr->zstream.next_out = comp->output;
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524 png_ptr->zstream.avail_out = (sizeof comp->output);
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526 output_len = png_ptr->zstream.avail_out;
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530 uInt avail_in = ZLIB_IO_MAX;
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532 if (avail_in > input_len)
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533 avail_in = (uInt)input_len;
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535 input_len -= avail_in;
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537 png_ptr->zstream.avail_in = avail_in;
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539 if (png_ptr->zstream.avail_out == 0)
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541 png_compression_buffer *next;
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543 /* Chunk data is limited to 2^31 bytes in length, so the prefix
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544 * length must be counted here.
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546 if (output_len + prefix_len > PNG_UINT_31_MAX)
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552 /* Need a new (malloc'ed) buffer, but there may be one present
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558 next = png_voidcast(png_compression_bufferp, png_malloc_base
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559 (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
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567 /* Link in this buffer (so that it will be freed later) */
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572 png_ptr->zstream.next_out = next->output;
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573 png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
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574 output_len += png_ptr->zstream.avail_out;
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576 /* Move 'end' to the next buffer pointer. */
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580 /* Compress the data */
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581 ret = deflate(&png_ptr->zstream,
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582 input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
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584 /* Claw back input data that was not consumed (because avail_in is
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585 * reset above every time round the loop).
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587 input_len += png_ptr->zstream.avail_in;
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588 png_ptr->zstream.avail_in = 0; /* safety */
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590 while (ret == Z_OK);
\r
592 /* There may be some space left in the last output buffer, this needs to
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593 * be subtracted from output_len.
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595 output_len -= png_ptr->zstream.avail_out;
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596 png_ptr->zstream.avail_out = 0; /* safety */
\r
597 comp->output_len = output_len;
\r
599 /* Now double check the output length, put in a custom message if it is
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600 * too long. Otherwise ensure the z_stream::msg pointer is set to
\r
603 if (output_len + prefix_len >= PNG_UINT_31_MAX)
\r
605 png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");
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610 png_zstream_error(png_ptr, ret);
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612 /* Reset zlib for another zTXt/iTXt or image data */
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613 png_ptr->zowner = 0;
\r
615 /* The only success case is Z_STREAM_END, input_len must be 0, if not this
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616 * is an internal error.
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618 if (ret == Z_STREAM_END && input_len == 0)
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620 /* Fix up the deflate header, if required */
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621 optimize_cmf(comp->output, comp->input_len);
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623 /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
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624 * function above to return Z_STREAM_END on an error (though it never
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625 * does in the current versions of zlib.)
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635 /* Ship the compressed text out via chunk writes */
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637 png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
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639 png_uint_32 output_len = comp->output_len;
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640 png_const_bytep output = comp->output;
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641 png_uint_32 avail = (sizeof comp->output);
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642 png_compression_buffer *next = png_ptr->zbuffer_list;
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646 if (avail > output_len)
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647 avail = output_len;
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649 png_write_chunk_data(png_ptr, output, avail);
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651 output_len -= avail;
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653 if (output_len == 0 || next == NULL)
\r
656 avail = png_ptr->zbuffer_size;
\r
657 output = next->output;
\r
661 /* This is an internal error; 'next' must have been NULL! */
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662 if (output_len > 0)
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663 png_error(png_ptr, "error writing ancillary chunked compressed data");
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665 #endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
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667 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
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668 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
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669 /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
\r
670 * and if invalid, correct the keyword rather than discarding the entire
\r
671 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
\r
672 * length, forbids leading or trailing whitespace, multiple internal spaces,
\r
673 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
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675 * The 'new_key' buffer must be 80 characters in size (for the keyword plus a
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676 * trailing '\0'). If this routine returns 0 then there was no keyword, or a
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677 * valid one could not be generated, and the caller must png_error.
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680 png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
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682 png_const_charp orig_key = key;
\r
683 png_uint_32 key_len = 0;
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684 int bad_character = 0;
\r
687 png_debug(1, "in png_check_keyword");
\r
695 while (*key && key_len < 79)
\r
697 png_byte ch = (png_byte)(0xff & *key++);
\r
699 if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
\r
700 *new_key++ = ch, ++key_len, space = 0;
\r
704 /* A space or an invalid character when one wasn't seen immediately
\r
705 * before; output just a space.
\r
707 *new_key++ = 32, ++key_len, space = 1;
\r
709 /* If the character was not a space then it is invalid. */
\r
711 bad_character = ch;
\r
714 else if (!bad_character)
\r
715 bad_character = ch; /* just skip it, record the first error */
\r
718 if (key_len > 0 && space) /* trailing space */
\r
720 --key_len, --new_key;
\r
721 if (!bad_character)
\r
722 bad_character = 32;
\r
725 /* Terminate the keyword */
\r
731 /* Try to only output one warning per keyword: */
\r
732 if (*key) /* keyword too long */
\r
733 png_warning(png_ptr, "keyword truncated");
\r
735 else if (bad_character)
\r
737 PNG_WARNING_PARAMETERS(p)
\r
739 png_warning_parameter(p, 1, orig_key);
\r
740 png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character);
\r
742 png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
\r
749 /* Write the IHDR chunk, and update the png_struct with the necessary
\r
750 * information. Note that the rest of this code depends upon this
\r
751 * information being correct.
\r
754 png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
\r
755 int bit_depth, int color_type, int compression_type, int filter_type,
\r
756 int interlace_type)
\r
758 png_byte buf[13]; /* Buffer to store the IHDR info */
\r
760 png_debug(1, "in png_write_IHDR");
\r
762 /* Check that we have valid input data from the application info */
\r
763 switch (color_type)
\r
765 case PNG_COLOR_TYPE_GRAY:
\r
772 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
775 png_ptr->channels = 1; break;
\r
779 "Invalid bit depth for grayscale image");
\r
783 case PNG_COLOR_TYPE_RGB:
\r
784 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
785 if (bit_depth != 8 && bit_depth != 16)
\r
787 if (bit_depth != 8)
\r
789 png_error(png_ptr, "Invalid bit depth for RGB image");
\r
791 png_ptr->channels = 3;
\r
794 case PNG_COLOR_TYPE_PALETTE:
\r
801 png_ptr->channels = 1;
\r
805 png_error(png_ptr, "Invalid bit depth for paletted image");
\r
809 case PNG_COLOR_TYPE_GRAY_ALPHA:
\r
810 if (bit_depth != 8 && bit_depth != 16)
\r
811 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
\r
813 png_ptr->channels = 2;
\r
816 case PNG_COLOR_TYPE_RGB_ALPHA:
\r
817 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
818 if (bit_depth != 8 && bit_depth != 16)
\r
820 if (bit_depth != 8)
\r
822 png_error(png_ptr, "Invalid bit depth for RGBA image");
\r
824 png_ptr->channels = 4;
\r
828 png_error(png_ptr, "Invalid image color type specified");
\r
831 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
\r
833 png_warning(png_ptr, "Invalid compression type specified");
\r
834 compression_type = PNG_COMPRESSION_TYPE_BASE;
\r
837 /* Write filter_method 64 (intrapixel differencing) only if
\r
838 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
\r
839 * 2. Libpng did not write a PNG signature (this filter_method is only
\r
840 * used in PNG datastreams that are embedded in MNG datastreams) and
\r
841 * 3. The application called png_permit_mng_features with a mask that
\r
842 * included PNG_FLAG_MNG_FILTER_64 and
\r
843 * 4. The filter_method is 64 and
\r
844 * 5. The color_type is RGB or RGBA
\r
847 #ifdef PNG_MNG_FEATURES_SUPPORTED
\r
848 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
\r
849 ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
\r
850 (color_type == PNG_COLOR_TYPE_RGB ||
\r
851 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
\r
852 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
\r
854 filter_type != PNG_FILTER_TYPE_BASE)
\r
856 png_warning(png_ptr, "Invalid filter type specified");
\r
857 filter_type = PNG_FILTER_TYPE_BASE;
\r
860 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
861 if (interlace_type != PNG_INTERLACE_NONE &&
\r
862 interlace_type != PNG_INTERLACE_ADAM7)
\r
864 png_warning(png_ptr, "Invalid interlace type specified");
\r
865 interlace_type = PNG_INTERLACE_ADAM7;
\r
868 interlace_type=PNG_INTERLACE_NONE;
\r
871 /* Save the relevent information */
\r
872 png_ptr->bit_depth = (png_byte)bit_depth;
\r
873 png_ptr->color_type = (png_byte)color_type;
\r
874 png_ptr->interlaced = (png_byte)interlace_type;
\r
875 #ifdef PNG_MNG_FEATURES_SUPPORTED
\r
876 png_ptr->filter_type = (png_byte)filter_type;
\r
878 png_ptr->compression_type = (png_byte)compression_type;
\r
879 png_ptr->width = width;
\r
880 png_ptr->height = height;
\r
882 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
\r
883 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
\r
884 /* Set the usr info, so any transformations can modify it */
\r
885 png_ptr->usr_width = png_ptr->width;
\r
886 png_ptr->usr_bit_depth = png_ptr->bit_depth;
\r
887 png_ptr->usr_channels = png_ptr->channels;
\r
889 /* Pack the header information into the buffer */
\r
890 png_save_uint_32(buf, width);
\r
891 png_save_uint_32(buf + 4, height);
\r
892 buf[8] = (png_byte)bit_depth;
\r
893 buf[9] = (png_byte)color_type;
\r
894 buf[10] = (png_byte)compression_type;
\r
895 buf[11] = (png_byte)filter_type;
\r
896 buf[12] = (png_byte)interlace_type;
\r
898 /* Write the chunk */
\r
899 png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
\r
901 if (!(png_ptr->do_filter))
\r
903 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
\r
904 png_ptr->bit_depth < 8)
\r
905 png_ptr->do_filter = PNG_FILTER_NONE;
\r
908 png_ptr->do_filter = PNG_ALL_FILTERS;
\r
911 png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
\r
914 /* Write the palette. We are careful not to trust png_color to be in the
\r
915 * correct order for PNG, so people can redefine it to any convenient
\r
919 png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
\r
920 png_uint_32 num_pal)
\r
923 png_const_colorp pal_ptr;
\r
926 png_debug(1, "in png_write_PLTE");
\r
929 #ifdef PNG_MNG_FEATURES_SUPPORTED
\r
930 !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
\r
932 num_pal == 0) || num_pal > 256)
\r
934 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
\r
936 png_error(png_ptr, "Invalid number of colors in palette");
\r
941 png_warning(png_ptr, "Invalid number of colors in palette");
\r
946 if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
\r
948 png_warning(png_ptr,
\r
949 "Ignoring request to write a PLTE chunk in grayscale PNG");
\r
954 png_ptr->num_palette = (png_uint_16)num_pal;
\r
955 png_debug1(3, "num_palette = %d", png_ptr->num_palette);
\r
957 png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
\r
958 #ifdef PNG_POINTER_INDEXING_SUPPORTED
\r
960 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
\r
962 buf[0] = pal_ptr->red;
\r
963 buf[1] = pal_ptr->green;
\r
964 buf[2] = pal_ptr->blue;
\r
965 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
\r
969 /* This is a little slower but some buggy compilers need to do this
\r
974 for (i = 0; i < num_pal; i++)
\r
976 buf[0] = pal_ptr[i].red;
\r
977 buf[1] = pal_ptr[i].green;
\r
978 buf[2] = pal_ptr[i].blue;
\r
979 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
\r
983 png_write_chunk_end(png_ptr);
\r
984 png_ptr->mode |= PNG_HAVE_PLTE;
\r
987 /* This is similar to png_text_compress, above, except that it does not require
\r
988 * all of the data at once and, instead of buffering the compressed result,
\r
989 * writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out
\r
990 * because it calls the write interface. As a result it does its own error
\r
991 * reporting and does not return an error code. In the event of error it will
\r
992 * just call png_error. The input data length may exceed 32-bits. The 'flush'
\r
993 * parameter is exactly the same as that to deflate, with the following
\r
996 * Z_NO_FLUSH: normal incremental output of compressed data
\r
997 * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush
\r
998 * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
\r
1000 * The routine manages the acquire and release of the png_ptr->zstream by
\r
1001 * checking and (at the end) clearing png_ptr->zowner, it does some sanity
\r
1002 * checks on the 'mode' flags while doing this.
\r
1004 void /* PRIVATE */
\r
1005 png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
\r
1006 png_alloc_size_t input_len, int flush)
\r
1008 if (png_ptr->zowner != png_IDAT)
\r
1010 /* First time. Ensure we have a temporary buffer for compression and
\r
1011 * trim the buffer list if it has more than one entry to free memory.
\r
1012 * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been
\r
1013 * created at this point, but the check here is quick and safe.
\r
1015 if (png_ptr->zbuffer_list == NULL)
\r
1017 png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,
\r
1018 png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
\r
1019 png_ptr->zbuffer_list->next = NULL;
\r
1023 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);
\r
1025 /* It is a terminal error if we can't claim the zstream. */
\r
1026 if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)
\r
1027 png_error(png_ptr, png_ptr->zstream.msg);
\r
1029 /* The output state is maintained in png_ptr->zstream, so it must be
\r
1030 * initialized here after the claim.
\r
1032 png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;
\r
1033 png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
\r
1036 /* Now loop reading and writing until all the input is consumed or an error
\r
1037 * terminates the operation. The _out values are maintained across calls to
\r
1038 * this function, but the input must be reset each time.
\r
1040 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
\r
1041 png_ptr->zstream.avail_in = 0; /* set below */
\r
1046 /* INPUT: from the row data */
\r
1047 uInt avail = ZLIB_IO_MAX;
\r
1049 if (avail > input_len)
\r
1050 avail = (uInt)input_len; /* safe because of the check */
\r
1052 png_ptr->zstream.avail_in = avail;
\r
1053 input_len -= avail;
\r
1055 ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);
\r
1057 /* Include as-yet unconsumed input */
\r
1058 input_len += png_ptr->zstream.avail_in;
\r
1059 png_ptr->zstream.avail_in = 0;
\r
1061 /* OUTPUT: write complete IDAT chunks when avail_out drops to zero, note
\r
1062 * that these two zstream fields are preserved across the calls, therefore
\r
1063 * there is no need to set these up on entry to the loop.
\r
1065 if (png_ptr->zstream.avail_out == 0)
\r
1067 png_bytep data = png_ptr->zbuffer_list->output;
\r
1068 uInt size = png_ptr->zbuffer_size;
\r
1070 /* Write an IDAT containing the data then reset the buffer. The
\r
1071 * first IDAT may need deflate header optimization.
\r
1073 # ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
\r
1074 if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
\r
1075 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
\r
1076 optimize_cmf(data, png_image_size(png_ptr));
\r
1079 png_write_complete_chunk(png_ptr, png_IDAT, data, size);
\r
1080 png_ptr->mode |= PNG_HAVE_IDAT;
\r
1082 png_ptr->zstream.next_out = data;
\r
1083 png_ptr->zstream.avail_out = size;
\r
1085 /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with
\r
1086 * the same flush parameter until it has finished output, for NO_FLUSH
\r
1087 * it doesn't matter.
\r
1089 if (ret == Z_OK && flush != Z_NO_FLUSH)
\r
1093 /* The order of these checks doesn't matter much; it just effect which
\r
1094 * possible error might be detected if multiple things go wrong at once.
\r
1096 if (ret == Z_OK) /* most likely return code! */
\r
1098 /* If all the input has been consumed then just return. If Z_FINISH
\r
1099 * was used as the flush parameter something has gone wrong if we get
\r
1102 if (input_len == 0)
\r
1104 if (flush == Z_FINISH)
\r
1105 png_error(png_ptr, "Z_OK on Z_FINISH with output space");
\r
1111 else if (ret == Z_STREAM_END && flush == Z_FINISH)
\r
1113 /* This is the end of the IDAT data; any pending output must be
\r
1114 * flushed. For small PNG files we may still be at the beginning.
\r
1116 png_bytep data = png_ptr->zbuffer_list->output;
\r
1117 uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;
\r
1119 # ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
\r
1120 if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
\r
1121 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
\r
1122 optimize_cmf(data, png_image_size(png_ptr));
\r
1125 png_write_complete_chunk(png_ptr, png_IDAT, data, size);
\r
1126 png_ptr->zstream.avail_out = 0;
\r
1127 png_ptr->zstream.next_out = NULL;
\r
1128 png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
\r
1130 png_ptr->zowner = 0; /* Release the stream */
\r
1136 /* This is an error condition. */
\r
1137 png_zstream_error(png_ptr, ret);
\r
1138 png_error(png_ptr, png_ptr->zstream.msg);
\r
1143 /* Write an IEND chunk */
\r
1144 void /* PRIVATE */
\r
1145 png_write_IEND(png_structrp png_ptr)
\r
1147 png_debug(1, "in png_write_IEND");
\r
1149 png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
\r
1150 png_ptr->mode |= PNG_HAVE_IEND;
\r
1153 #ifdef PNG_WRITE_gAMA_SUPPORTED
\r
1154 /* Write a gAMA chunk */
\r
1155 void /* PRIVATE */
\r
1156 png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)
\r
1160 png_debug(1, "in png_write_gAMA");
\r
1162 /* file_gamma is saved in 1/100,000ths */
\r
1163 png_save_uint_32(buf, (png_uint_32)file_gamma);
\r
1164 png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
\r
1168 #ifdef PNG_WRITE_sRGB_SUPPORTED
\r
1169 /* Write a sRGB chunk */
\r
1170 void /* PRIVATE */
\r
1171 png_write_sRGB(png_structrp png_ptr, int srgb_intent)
\r
1175 png_debug(1, "in png_write_sRGB");
\r
1177 if (srgb_intent >= PNG_sRGB_INTENT_LAST)
\r
1178 png_warning(png_ptr,
\r
1179 "Invalid sRGB rendering intent specified");
\r
1181 buf[0]=(png_byte)srgb_intent;
\r
1182 png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
\r
1186 #ifdef PNG_WRITE_iCCP_SUPPORTED
\r
1187 /* Write an iCCP chunk */
\r
1188 void /* PRIVATE */
\r
1189 png_write_iCCP(png_structrp png_ptr, png_const_charp name,
\r
1190 png_const_bytep profile)
\r
1192 png_uint_32 name_len;
\r
1193 png_uint_32 profile_len;
\r
1194 png_byte new_name[81]; /* 1 byte for the compression byte */
\r
1195 compression_state comp;
\r
1197 png_debug(1, "in png_write_iCCP");
\r
1199 /* These are all internal problems: the profile should have been checked
\r
1200 * before when it was stored.
\r
1202 if (profile == NULL)
\r
1203 png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
\r
1205 profile_len = png_get_uint_32(profile);
\r
1207 if (profile_len < 132)
\r
1208 png_error(png_ptr, "ICC profile too short");
\r
1210 if (profile_len & 0x03)
\r
1211 png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
\r
1214 png_uint_32 embedded_profile_len = png_get_uint_32(profile);
\r
1216 if (profile_len != embedded_profile_len)
\r
1217 png_error(png_ptr, "Profile length does not match profile");
\r
1220 name_len = png_check_keyword(png_ptr, name, new_name);
\r
1222 if (name_len == 0)
\r
1223 png_error(png_ptr, "iCCP: invalid keyword");
\r
1225 new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;
\r
1227 /* Make sure we include the NULL after the name and the compression type */
\r
1230 png_text_compress_init(&comp, profile, profile_len);
\r
1232 /* Allow for keyword terminator and compression byte */
\r
1233 if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)
\r
1234 png_error(png_ptr, png_ptr->zstream.msg);
\r
1236 png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);
\r
1238 png_write_chunk_data(png_ptr, new_name, name_len);
\r
1240 png_write_compressed_data_out(png_ptr, &comp);
\r
1242 png_write_chunk_end(png_ptr);
\r
1246 #ifdef PNG_WRITE_sPLT_SUPPORTED
\r
1247 /* Write a sPLT chunk */
\r
1248 void /* PRIVATE */
\r
1249 png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
\r
1251 png_uint_32 name_len;
\r
1252 png_byte new_name[80];
\r
1253 png_byte entrybuf[10];
\r
1254 png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
\r
1255 png_size_t palette_size = entry_size * spalette->nentries;
\r
1256 png_sPLT_entryp ep;
\r
1257 #ifndef PNG_POINTER_INDEXING_SUPPORTED
\r
1261 png_debug(1, "in png_write_sPLT");
\r
1263 name_len = png_check_keyword(png_ptr, spalette->name, new_name);
\r
1265 if (name_len == 0)
\r
1266 png_error(png_ptr, "sPLT: invalid keyword");
\r
1268 /* Make sure we include the NULL after the name */
\r
1269 png_write_chunk_header(png_ptr, png_sPLT,
\r
1270 (png_uint_32)(name_len + 2 + palette_size));
\r
1272 png_write_chunk_data(png_ptr, (png_bytep)new_name,
\r
1273 (png_size_t)(name_len + 1));
\r
1275 png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);
\r
1277 /* Loop through each palette entry, writing appropriately */
\r
1278 #ifdef PNG_POINTER_INDEXING_SUPPORTED
\r
1279 for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
\r
1281 if (spalette->depth == 8)
\r
1283 entrybuf[0] = (png_byte)ep->red;
\r
1284 entrybuf[1] = (png_byte)ep->green;
\r
1285 entrybuf[2] = (png_byte)ep->blue;
\r
1286 entrybuf[3] = (png_byte)ep->alpha;
\r
1287 png_save_uint_16(entrybuf + 4, ep->frequency);
\r
1292 png_save_uint_16(entrybuf + 0, ep->red);
\r
1293 png_save_uint_16(entrybuf + 2, ep->green);
\r
1294 png_save_uint_16(entrybuf + 4, ep->blue);
\r
1295 png_save_uint_16(entrybuf + 6, ep->alpha);
\r
1296 png_save_uint_16(entrybuf + 8, ep->frequency);
\r
1299 png_write_chunk_data(png_ptr, entrybuf, entry_size);
\r
1302 ep=spalette->entries;
\r
1303 for (i = 0; i>spalette->nentries; i++)
\r
1305 if (spalette->depth == 8)
\r
1307 entrybuf[0] = (png_byte)ep[i].red;
\r
1308 entrybuf[1] = (png_byte)ep[i].green;
\r
1309 entrybuf[2] = (png_byte)ep[i].blue;
\r
1310 entrybuf[3] = (png_byte)ep[i].alpha;
\r
1311 png_save_uint_16(entrybuf + 4, ep[i].frequency);
\r
1316 png_save_uint_16(entrybuf + 0, ep[i].red);
\r
1317 png_save_uint_16(entrybuf + 2, ep[i].green);
\r
1318 png_save_uint_16(entrybuf + 4, ep[i].blue);
\r
1319 png_save_uint_16(entrybuf + 6, ep[i].alpha);
\r
1320 png_save_uint_16(entrybuf + 8, ep[i].frequency);
\r
1323 png_write_chunk_data(png_ptr, entrybuf, entry_size);
\r
1327 png_write_chunk_end(png_ptr);
\r
1331 #ifdef PNG_WRITE_sBIT_SUPPORTED
\r
1332 /* Write the sBIT chunk */
\r
1333 void /* PRIVATE */
\r
1334 png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
\r
1339 png_debug(1, "in png_write_sBIT");
\r
1341 /* Make sure we don't depend upon the order of PNG_COLOR_8 */
\r
1342 if (color_type & PNG_COLOR_MASK_COLOR)
\r
1346 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
\r
1347 png_ptr->usr_bit_depth);
\r
1349 if (sbit->red == 0 || sbit->red > maxbits ||
\r
1350 sbit->green == 0 || sbit->green > maxbits ||
\r
1351 sbit->blue == 0 || sbit->blue > maxbits)
\r
1353 png_warning(png_ptr, "Invalid sBIT depth specified");
\r
1357 buf[0] = sbit->red;
\r
1358 buf[1] = sbit->green;
\r
1359 buf[2] = sbit->blue;
\r
1365 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
\r
1367 png_warning(png_ptr, "Invalid sBIT depth specified");
\r
1371 buf[0] = sbit->gray;
\r
1375 if (color_type & PNG_COLOR_MASK_ALPHA)
\r
1377 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
\r
1379 png_warning(png_ptr, "Invalid sBIT depth specified");
\r
1383 buf[size++] = sbit->alpha;
\r
1386 png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
\r
1390 #ifdef PNG_WRITE_cHRM_SUPPORTED
\r
1391 /* Write the cHRM chunk */
\r
1392 void /* PRIVATE */
\r
1393 png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)
\r
1397 png_debug(1, "in png_write_cHRM");
\r
1399 /* Each value is saved in 1/100,000ths */
\r
1400 png_save_int_32(buf, xy->whitex);
\r
1401 png_save_int_32(buf + 4, xy->whitey);
\r
1403 png_save_int_32(buf + 8, xy->redx);
\r
1404 png_save_int_32(buf + 12, xy->redy);
\r
1406 png_save_int_32(buf + 16, xy->greenx);
\r
1407 png_save_int_32(buf + 20, xy->greeny);
\r
1409 png_save_int_32(buf + 24, xy->bluex);
\r
1410 png_save_int_32(buf + 28, xy->bluey);
\r
1412 png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);
\r
1416 #ifdef PNG_WRITE_tRNS_SUPPORTED
\r
1417 /* Write the tRNS chunk */
\r
1418 void /* PRIVATE */
\r
1419 png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
\r
1420 png_const_color_16p tran, int num_trans, int color_type)
\r
1424 png_debug(1, "in png_write_tRNS");
\r
1426 if (color_type == PNG_COLOR_TYPE_PALETTE)
\r
1428 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
\r
1430 png_app_warning(png_ptr,
\r
1431 "Invalid number of transparent colors specified");
\r
1435 /* Write the chunk out as it is */
\r
1436 png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
\r
1437 (png_size_t)num_trans);
\r
1440 else if (color_type == PNG_COLOR_TYPE_GRAY)
\r
1442 /* One 16 bit value */
\r
1443 if (tran->gray >= (1 << png_ptr->bit_depth))
\r
1445 png_app_warning(png_ptr,
\r
1446 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
\r
1451 png_save_uint_16(buf, tran->gray);
\r
1452 png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
\r
1455 else if (color_type == PNG_COLOR_TYPE_RGB)
\r
1457 /* Three 16 bit values */
\r
1458 png_save_uint_16(buf, tran->red);
\r
1459 png_save_uint_16(buf + 2, tran->green);
\r
1460 png_save_uint_16(buf + 4, tran->blue);
\r
1461 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
1462 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
\r
1464 if (buf[0] | buf[2] | buf[4])
\r
1467 png_app_warning(png_ptr,
\r
1468 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
\r
1472 png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
\r
1477 png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
\r
1482 #ifdef PNG_WRITE_bKGD_SUPPORTED
\r
1483 /* Write the background chunk */
\r
1484 void /* PRIVATE */
\r
1485 png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
\r
1489 png_debug(1, "in png_write_bKGD");
\r
1491 if (color_type == PNG_COLOR_TYPE_PALETTE)
\r
1494 #ifdef PNG_MNG_FEATURES_SUPPORTED
\r
1495 (png_ptr->num_palette ||
\r
1496 (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
\r
1498 back->index >= png_ptr->num_palette)
\r
1500 png_warning(png_ptr, "Invalid background palette index");
\r
1504 buf[0] = back->index;
\r
1505 png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
\r
1508 else if (color_type & PNG_COLOR_MASK_COLOR)
\r
1510 png_save_uint_16(buf, back->red);
\r
1511 png_save_uint_16(buf + 2, back->green);
\r
1512 png_save_uint_16(buf + 4, back->blue);
\r
1513 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
1514 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
\r
1516 if (buf[0] | buf[2] | buf[4])
\r
1519 png_warning(png_ptr,
\r
1520 "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
\r
1525 png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
\r
1530 if (back->gray >= (1 << png_ptr->bit_depth))
\r
1532 png_warning(png_ptr,
\r
1533 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
\r
1538 png_save_uint_16(buf, back->gray);
\r
1539 png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
\r
1544 #ifdef PNG_WRITE_hIST_SUPPORTED
\r
1545 /* Write the histogram */
\r
1546 void /* PRIVATE */
\r
1547 png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
\r
1552 png_debug(1, "in png_write_hIST");
\r
1554 if (num_hist > (int)png_ptr->num_palette)
\r
1556 png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
\r
1557 png_ptr->num_palette);
\r
1559 png_warning(png_ptr, "Invalid number of histogram entries specified");
\r
1563 png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
\r
1565 for (i = 0; i < num_hist; i++)
\r
1567 png_save_uint_16(buf, hist[i]);
\r
1568 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
\r
1571 png_write_chunk_end(png_ptr);
\r
1575 #ifdef PNG_WRITE_tEXt_SUPPORTED
\r
1576 /* Write a tEXt chunk */
\r
1577 void /* PRIVATE */
\r
1578 png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
\r
1579 png_size_t text_len)
\r
1581 png_uint_32 key_len;
\r
1582 png_byte new_key[80];
\r
1584 png_debug(1, "in png_write_tEXt");
\r
1586 key_len = png_check_keyword(png_ptr, key, new_key);
\r
1589 png_error(png_ptr, "tEXt: invalid keyword");
\r
1591 if (text == NULL || *text == '\0')
\r
1595 text_len = strlen(text);
\r
1597 if (text_len > PNG_UINT_31_MAX - (key_len+1))
\r
1598 png_error(png_ptr, "tEXt: text too long");
\r
1600 /* Make sure we include the 0 after the key */
\r
1601 png_write_chunk_header(png_ptr, png_tEXt,
\r
1602 (png_uint_32)/*checked above*/(key_len + text_len + 1));
\r
1604 * We leave it to the application to meet PNG-1.0 requirements on the
\r
1605 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
\r
1606 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
\r
1607 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
\r
1609 png_write_chunk_data(png_ptr, new_key, key_len + 1);
\r
1612 png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);
\r
1614 png_write_chunk_end(png_ptr);
\r
1618 #ifdef PNG_WRITE_zTXt_SUPPORTED
\r
1619 /* Write a compressed text chunk */
\r
1620 void /* PRIVATE */
\r
1621 png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
\r
1622 png_size_t text_len, int compression)
\r
1624 png_uint_32 key_len;
\r
1625 png_byte new_key[81];
\r
1626 compression_state comp;
\r
1628 png_debug(1, "in png_write_zTXt");
\r
1629 PNG_UNUSED(text_len) /* Always use strlen */
\r
1631 if (compression == PNG_TEXT_COMPRESSION_NONE)
\r
1633 png_write_tEXt(png_ptr, key, text, 0);
\r
1637 if (compression != PNG_TEXT_COMPRESSION_zTXt)
\r
1638 png_error(png_ptr, "zTXt: invalid compression type");
\r
1640 key_len = png_check_keyword(png_ptr, key, new_key);
\r
1643 png_error(png_ptr, "zTXt: invalid keyword");
\r
1645 /* Add the compression method and 1 for the keyword separator. */
\r
1646 new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
\r
1649 /* Compute the compressed data; do it now for the length */
\r
1650 png_text_compress_init(&comp, (png_const_bytep)text,
\r
1651 text == NULL ? 0 : strlen(text));
\r
1653 if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK)
\r
1654 png_error(png_ptr, png_ptr->zstream.msg);
\r
1656 /* Write start of chunk */
\r
1657 png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len);
\r
1660 png_write_chunk_data(png_ptr, new_key, key_len);
\r
1662 /* Write the compressed data */
\r
1663 png_write_compressed_data_out(png_ptr, &comp);
\r
1665 /* Close the chunk */
\r
1666 png_write_chunk_end(png_ptr);
\r
1670 #ifdef PNG_WRITE_iTXt_SUPPORTED
\r
1671 /* Write an iTXt chunk */
\r
1672 void /* PRIVATE */
\r
1673 png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
\r
1674 png_const_charp lang, png_const_charp lang_key, png_const_charp text)
\r
1676 png_uint_32 key_len, prefix_len;
\r
1677 png_size_t lang_len, lang_key_len;
\r
1678 png_byte new_key[82];
\r
1679 compression_state comp;
\r
1681 png_debug(1, "in png_write_iTXt");
\r
1683 key_len = png_check_keyword(png_ptr, key, new_key);
\r
1686 png_error(png_ptr, "iTXt: invalid keyword");
\r
1688 /* Set the compression flag */
\r
1689 switch (compression)
\r
1691 case PNG_ITXT_COMPRESSION_NONE:
\r
1692 case PNG_TEXT_COMPRESSION_NONE:
\r
1693 compression = new_key[++key_len] = 0; /* no compression */
\r
1696 case PNG_TEXT_COMPRESSION_zTXt:
\r
1697 case PNG_ITXT_COMPRESSION_zTXt:
\r
1698 compression = new_key[++key_len] = 1; /* compressed */
\r
1702 png_error(png_ptr, "iTXt: invalid compression");
\r
1705 new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
\r
1706 ++key_len; /* for the keywod separator */
\r
1708 /* We leave it to the application to meet PNG-1.0 requirements on the
\r
1709 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
\r
1710 * any non-Latin-1 characters except for NEWLINE. ISO PNG, however,
\r
1711 * specifies that the text is UTF-8 and this really doesn't require any
\r
1714 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
\r
1716 * TODO: validate the language tag correctly (see the spec.)
\r
1718 if (lang == NULL) lang = ""; /* empty language is valid */
\r
1719 lang_len = strlen(lang)+1;
\r
1720 if (lang_key == NULL) lang_key = ""; /* may be empty */
\r
1721 lang_key_len = strlen(lang_key)+1;
\r
1722 if (text == NULL) text = ""; /* may be empty */
\r
1724 prefix_len = key_len;
\r
1725 if (lang_len > PNG_UINT_31_MAX-prefix_len)
\r
1726 prefix_len = PNG_UINT_31_MAX;
\r
1728 prefix_len = (png_uint_32)(prefix_len + lang_len);
\r
1730 if (lang_key_len > PNG_UINT_31_MAX-prefix_len)
\r
1731 prefix_len = PNG_UINT_31_MAX;
\r
1733 prefix_len = (png_uint_32)(prefix_len + lang_key_len);
\r
1735 png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));
\r
1739 if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
\r
1740 png_error(png_ptr, png_ptr->zstream.msg);
\r
1745 if (comp.input_len > PNG_UINT_31_MAX-prefix_len)
\r
1746 png_error(png_ptr, "iTXt: uncompressed text too long");
\r
1748 /* So the string will fit in a chunk: */
\r
1749 comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;
\r
1752 png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);
\r
1754 png_write_chunk_data(png_ptr, new_key, key_len);
\r
1756 png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);
\r
1758 png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);
\r
1761 png_write_compressed_data_out(png_ptr, &comp);
\r
1764 png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.input_len);
\r
1766 png_write_chunk_end(png_ptr);
\r
1770 #ifdef PNG_WRITE_oFFs_SUPPORTED
\r
1771 /* Write the oFFs chunk */
\r
1772 void /* PRIVATE */
\r
1773 png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
\r
1778 png_debug(1, "in png_write_oFFs");
\r
1780 if (unit_type >= PNG_OFFSET_LAST)
\r
1781 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
\r
1783 png_save_int_32(buf, x_offset);
\r
1784 png_save_int_32(buf + 4, y_offset);
\r
1785 buf[8] = (png_byte)unit_type;
\r
1787 png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
\r
1790 #ifdef PNG_WRITE_pCAL_SUPPORTED
\r
1791 /* Write the pCAL chunk (described in the PNG extensions document) */
\r
1792 void /* PRIVATE */
\r
1793 png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
\r
1794 png_int_32 X1, int type, int nparams, png_const_charp units,
\r
1795 png_charpp params)
\r
1797 png_uint_32 purpose_len;
\r
1798 png_size_t units_len, total_len;
\r
1799 png_size_tp params_len;
\r
1801 png_byte new_purpose[80];
\r
1804 png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
\r
1806 if (type >= PNG_EQUATION_LAST)
\r
1807 png_error(png_ptr, "Unrecognized equation type for pCAL chunk");
\r
1809 purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);
\r
1811 if (purpose_len == 0)
\r
1812 png_error(png_ptr, "pCAL: invalid keyword");
\r
1814 ++purpose_len; /* terminator */
\r
1816 png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
\r
1817 units_len = strlen(units) + (nparams == 0 ? 0 : 1);
\r
1818 png_debug1(3, "pCAL units length = %d", (int)units_len);
\r
1819 total_len = purpose_len + units_len + 10;
\r
1821 params_len = (png_size_tp)png_malloc(png_ptr,
\r
1822 (png_alloc_size_t)(nparams * (sizeof (png_size_t))));
\r
1824 /* Find the length of each parameter, making sure we don't count the
\r
1825 * null terminator for the last parameter.
\r
1827 for (i = 0; i < nparams; i++)
\r
1829 params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
\r
1830 png_debug2(3, "pCAL parameter %d length = %lu", i,
\r
1831 (unsigned long)params_len[i]);
\r
1832 total_len += params_len[i];
\r
1835 png_debug1(3, "pCAL total length = %d", (int)total_len);
\r
1836 png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
\r
1837 png_write_chunk_data(png_ptr, new_purpose, purpose_len);
\r
1838 png_save_int_32(buf, X0);
\r
1839 png_save_int_32(buf + 4, X1);
\r
1840 buf[8] = (png_byte)type;
\r
1841 buf[9] = (png_byte)nparams;
\r
1842 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
\r
1843 png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
\r
1845 for (i = 0; i < nparams; i++)
\r
1847 png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
\r
1850 png_free(png_ptr, params_len);
\r
1851 png_write_chunk_end(png_ptr);
\r
1855 #ifdef PNG_WRITE_sCAL_SUPPORTED
\r
1856 /* Write the sCAL chunk */
\r
1857 void /* PRIVATE */
\r
1858 png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
\r
1859 png_const_charp height)
\r
1862 png_size_t wlen, hlen, total_len;
\r
1864 png_debug(1, "in png_write_sCAL_s");
\r
1866 wlen = strlen(width);
\r
1867 hlen = strlen(height);
\r
1868 total_len = wlen + hlen + 2;
\r
1870 if (total_len > 64)
\r
1872 png_warning(png_ptr, "Can't write sCAL (buffer too small)");
\r
1876 buf[0] = (png_byte)unit;
\r
1877 memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */
\r
1878 memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
\r
1880 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
\r
1881 png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
\r
1885 #ifdef PNG_WRITE_pHYs_SUPPORTED
\r
1886 /* Write the pHYs chunk */
\r
1887 void /* PRIVATE */
\r
1888 png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,
\r
1889 png_uint_32 y_pixels_per_unit,
\r
1894 png_debug(1, "in png_write_pHYs");
\r
1896 if (unit_type >= PNG_RESOLUTION_LAST)
\r
1897 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
\r
1899 png_save_uint_32(buf, x_pixels_per_unit);
\r
1900 png_save_uint_32(buf + 4, y_pixels_per_unit);
\r
1901 buf[8] = (png_byte)unit_type;
\r
1903 png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
\r
1907 #ifdef PNG_WRITE_tIME_SUPPORTED
\r
1908 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
\r
1909 * or png_convert_from_time_t(), or fill in the structure yourself.
\r
1911 void /* PRIVATE */
\r
1912 png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
\r
1916 png_debug(1, "in png_write_tIME");
\r
1918 if (mod_time->month > 12 || mod_time->month < 1 ||
\r
1919 mod_time->day > 31 || mod_time->day < 1 ||
\r
1920 mod_time->hour > 23 || mod_time->second > 60)
\r
1922 png_warning(png_ptr, "Invalid time specified for tIME chunk");
\r
1926 png_save_uint_16(buf, mod_time->year);
\r
1927 buf[2] = mod_time->month;
\r
1928 buf[3] = mod_time->day;
\r
1929 buf[4] = mod_time->hour;
\r
1930 buf[5] = mod_time->minute;
\r
1931 buf[6] = mod_time->second;
\r
1933 png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
\r
1937 /* Initializes the row writing capability of libpng */
\r
1938 void /* PRIVATE */
\r
1939 png_write_start_row(png_structrp png_ptr)
\r
1941 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
1942 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
\r
1944 /* Start of interlace block */
\r
1945 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
\r
1947 /* Offset to next interlace block */
\r
1948 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
\r
1950 /* Start of interlace block in the y direction */
\r
1951 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
\r
1953 /* Offset to next interlace block in the y direction */
\r
1954 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
\r
1957 png_alloc_size_t buf_size;
\r
1958 int usr_pixel_depth;
\r
1960 png_debug(1, "in png_write_start_row");
\r
1962 usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
\r
1963 buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
\r
1965 /* 1.5.6: added to allow checking in the row write code. */
\r
1966 png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
\r
1967 png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
\r
1969 /* Set up row buffer */
\r
1970 png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);
\r
1972 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
\r
1974 #ifdef PNG_WRITE_FILTER_SUPPORTED
\r
1975 /* Set up filtering buffer, if using this filter */
\r
1976 if (png_ptr->do_filter & PNG_FILTER_SUB)
\r
1978 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);
\r
1980 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
\r
1983 /* We only need to keep the previous row if we are using one of these. */
\r
1984 if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
\r
1986 /* Set up previous row buffer */
\r
1987 png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);
\r
1989 if (png_ptr->do_filter & PNG_FILTER_UP)
\r
1991 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
\r
1992 png_ptr->rowbytes + 1);
\r
1994 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
\r
1997 if (png_ptr->do_filter & PNG_FILTER_AVG)
\r
1999 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
\r
2000 png_ptr->rowbytes + 1);
\r
2002 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
\r
2005 if (png_ptr->do_filter & PNG_FILTER_PAETH)
\r
2007 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
\r
2008 png_ptr->rowbytes + 1);
\r
2010 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
\r
2013 #endif /* PNG_WRITE_FILTER_SUPPORTED */
\r
2015 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
2016 /* If interlaced, we need to set up width and height of pass */
\r
2017 if (png_ptr->interlaced)
\r
2019 if (!(png_ptr->transformations & PNG_INTERLACE))
\r
2021 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
\r
2022 png_pass_ystart[0]) / png_pass_yinc[0];
\r
2024 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
\r
2025 png_pass_start[0]) / png_pass_inc[0];
\r
2030 png_ptr->num_rows = png_ptr->height;
\r
2031 png_ptr->usr_width = png_ptr->width;
\r
2038 png_ptr->num_rows = png_ptr->height;
\r
2039 png_ptr->usr_width = png_ptr->width;
\r
2043 /* Internal use only. Called when finished processing a row of data. */
\r
2044 void /* PRIVATE */
\r
2045 png_write_finish_row(png_structrp png_ptr)
\r
2047 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
2048 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
\r
2050 /* Start of interlace block */
\r
2051 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
\r
2053 /* Offset to next interlace block */
\r
2054 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
\r
2056 /* Start of interlace block in the y direction */
\r
2057 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
\r
2059 /* Offset to next interlace block in the y direction */
\r
2060 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
\r
2063 png_debug(1, "in png_write_finish_row");
\r
2066 png_ptr->row_number++;
\r
2068 /* See if we are done */
\r
2069 if (png_ptr->row_number < png_ptr->num_rows)
\r
2072 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
2073 /* If interlaced, go to next pass */
\r
2074 if (png_ptr->interlaced)
\r
2076 png_ptr->row_number = 0;
\r
2077 if (png_ptr->transformations & PNG_INTERLACE)
\r
2084 /* Loop until we find a non-zero width or height pass */
\r
2089 if (png_ptr->pass >= 7)
\r
2092 png_ptr->usr_width = (png_ptr->width +
\r
2093 png_pass_inc[png_ptr->pass] - 1 -
\r
2094 png_pass_start[png_ptr->pass]) /
\r
2095 png_pass_inc[png_ptr->pass];
\r
2097 png_ptr->num_rows = (png_ptr->height +
\r
2098 png_pass_yinc[png_ptr->pass] - 1 -
\r
2099 png_pass_ystart[png_ptr->pass]) /
\r
2100 png_pass_yinc[png_ptr->pass];
\r
2102 if (png_ptr->transformations & PNG_INTERLACE)
\r
2105 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
\r
2109 /* Reset the row above the image for the next pass */
\r
2110 if (png_ptr->pass < 7)
\r
2112 if (png_ptr->prev_row != NULL)
\r
2113 memset(png_ptr->prev_row, 0,
\r
2114 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
\r
2115 png_ptr->usr_bit_depth, png_ptr->width)) + 1);
\r
2122 /* If we get here, we've just written the last row, so we need
\r
2123 to flush the compressor */
\r
2124 png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);
\r
2127 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
2128 /* Pick out the correct pixels for the interlace pass.
\r
2129 * The basic idea here is to go through the row with a source
\r
2130 * pointer and a destination pointer (sp and dp), and copy the
\r
2131 * correct pixels for the pass. As the row gets compacted,
\r
2132 * sp will always be >= dp, so we should never overwrite anything.
\r
2133 * See the default: case for the easiest code to understand.
\r
2135 void /* PRIVATE */
\r
2136 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
\r
2138 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
\r
2140 /* Start of interlace block */
\r
2141 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
\r
2143 /* Offset to next interlace block */
\r
2144 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
\r
2146 png_debug(1, "in png_do_write_interlace");
\r
2148 /* We don't have to do anything on the last pass (6) */
\r
2151 /* Each pixel depth is handled separately */
\r
2152 switch (row_info->pixel_depth)
\r
2162 png_uint_32 row_width = row_info->width;
\r
2168 for (i = png_pass_start[pass]; i < row_width;
\r
2169 i += png_pass_inc[pass])
\r
2171 sp = row + (png_size_t)(i >> 3);
\r
2172 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
\r
2173 d |= (value << shift);
\r
2178 *dp++ = (png_byte)d;
\r
2187 *dp = (png_byte)d;
\r
2200 png_uint_32 row_width = row_info->width;
\r
2206 for (i = png_pass_start[pass]; i < row_width;
\r
2207 i += png_pass_inc[pass])
\r
2209 sp = row + (png_size_t)(i >> 2);
\r
2210 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
\r
2211 d |= (value << shift);
\r
2216 *dp++ = (png_byte)d;
\r
2224 *dp = (png_byte)d;
\r
2237 png_uint_32 row_width = row_info->width;
\r
2242 for (i = png_pass_start[pass]; i < row_width;
\r
2243 i += png_pass_inc[pass])
\r
2245 sp = row + (png_size_t)(i >> 1);
\r
2246 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
\r
2247 d |= (value << shift);
\r
2252 *dp++ = (png_byte)d;
\r
2260 *dp = (png_byte)d;
\r
2270 png_uint_32 row_width = row_info->width;
\r
2271 png_size_t pixel_bytes;
\r
2273 /* Start at the beginning */
\r
2276 /* Find out how many bytes each pixel takes up */
\r
2277 pixel_bytes = (row_info->pixel_depth >> 3);
\r
2279 /* Loop through the row, only looking at the pixels that matter */
\r
2280 for (i = png_pass_start[pass]; i < row_width;
\r
2281 i += png_pass_inc[pass])
\r
2283 /* Find out where the original pixel is */
\r
2284 sp = row + (png_size_t)i * pixel_bytes;
\r
2286 /* Move the pixel */
\r
2288 memcpy(dp, sp, pixel_bytes);
\r
2291 dp += pixel_bytes;
\r
2296 /* Set new row width */
\r
2297 row_info->width = (row_info->width +
\r
2298 png_pass_inc[pass] - 1 -
\r
2299 png_pass_start[pass]) /
\r
2300 png_pass_inc[pass];
\r
2302 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
\r
2308 /* This filters the row, chooses which filter to use, if it has not already
\r
2309 * been specified by the application, and then writes the row out with the
\r
2312 static void png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
\r
2313 png_size_t row_bytes);
\r
2315 #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
\r
2316 #define PNG_HISHIFT 10
\r
2317 #define PNG_LOMASK ((png_uint_32)0xffffL)
\r
2318 #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
\r
2319 void /* PRIVATE */
\r
2320 png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
\r
2322 png_bytep best_row;
\r
2323 #ifdef PNG_WRITE_FILTER_SUPPORTED
\r
2324 png_bytep prev_row, row_buf;
\r
2325 png_uint_32 mins, bpp;
\r
2326 png_byte filter_to_do = png_ptr->do_filter;
\r
2327 png_size_t row_bytes = row_info->rowbytes;
\r
2328 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2329 int num_p_filters = png_ptr->num_prev_filters;
\r
2332 png_debug(1, "in png_write_find_filter");
\r
2334 #ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2335 if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)
\r
2337 /* These will never be selected so we need not test them. */
\r
2338 filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);
\r
2342 /* Find out how many bytes offset each pixel is */
\r
2343 bpp = (row_info->pixel_depth + 7) >> 3;
\r
2345 prev_row = png_ptr->prev_row;
\r
2347 best_row = png_ptr->row_buf;
\r
2348 #ifdef PNG_WRITE_FILTER_SUPPORTED
\r
2349 row_buf = best_row;
\r
2350 mins = PNG_MAXSUM;
\r
2352 /* The prediction method we use is to find which method provides the
\r
2353 * smallest value when summing the absolute values of the distances
\r
2354 * from zero, using anything >= 128 as negative numbers. This is known
\r
2355 * as the "minimum sum of absolute differences" heuristic. Other
\r
2356 * heuristics are the "weighted minimum sum of absolute differences"
\r
2357 * (experimental and can in theory improve compression), and the "zlib
\r
2358 * predictive" method (not implemented yet), which does test compressions
\r
2359 * of lines using different filter methods, and then chooses the
\r
2360 * (series of) filter(s) that give minimum compressed data size (VERY
\r
2361 * computationally expensive).
\r
2363 * GRR 980525: consider also
\r
2365 * (1) minimum sum of absolute differences from running average (i.e.,
\r
2366 * keep running sum of non-absolute differences & count of bytes)
\r
2367 * [track dispersion, too? restart average if dispersion too large?]
\r
2369 * (1b) minimum sum of absolute differences from sliding average, probably
\r
2370 * with window size <= deflate window (usually 32K)
\r
2372 * (2) minimum sum of squared differences from zero or running average
\r
2373 * (i.e., ~ root-mean-square approach)
\r
2377 /* We don't need to test the 'no filter' case if this is the only filter
\r
2378 * that has been chosen, as it doesn't actually do anything to the data.
\r
2380 if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE)
\r
2383 png_uint_32 sum = 0;
\r
2387 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
\r
2390 sum += (v < 128) ? v : 256 - v;
\r
2393 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2394 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2396 png_uint_32 sumhi, sumlo;
\r
2398 sumlo = sum & PNG_LOMASK;
\r
2399 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
\r
2401 /* Reduce the sum if we match any of the previous rows */
\r
2402 for (j = 0; j < num_p_filters; j++)
\r
2404 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
\r
2406 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
\r
2409 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
\r
2414 /* Factor in the cost of this filter (this is here for completeness,
\r
2415 * but it makes no sense to have a "cost" for the NONE filter, as
\r
2416 * it has the minimum possible computational cost - none).
\r
2418 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
\r
2421 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
\r
2424 if (sumhi > PNG_HIMASK)
\r
2428 sum = (sumhi << PNG_HISHIFT) + sumlo;
\r
2435 if (filter_to_do == PNG_FILTER_SUB)
\r
2436 /* It's the only filter so no testing is needed */
\r
2438 png_bytep rp, lp, dp;
\r
2441 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
\r
2447 for (lp = row_buf + 1; i < row_bytes;
\r
2448 i++, rp++, lp++, dp++)
\r
2450 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
\r
2453 best_row = png_ptr->sub_row;
\r
2456 else if (filter_to_do & PNG_FILTER_SUB)
\r
2458 png_bytep rp, dp, lp;
\r
2459 png_uint_32 sum = 0, lmins = mins;
\r
2463 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2464 /* We temporarily increase the "minimum sum" by the factor we
\r
2465 * would reduce the sum of this filter, so that we can do the
\r
2466 * early exit comparison without scaling the sum each time.
\r
2468 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2471 png_uint_32 lmhi, lmlo;
\r
2472 lmlo = lmins & PNG_LOMASK;
\r
2473 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
\r
2475 for (j = 0; j < num_p_filters; j++)
\r
2477 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
\r
2479 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
\r
2482 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
\r
2487 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
\r
2490 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
\r
2493 if (lmhi > PNG_HIMASK)
\r
2494 lmins = PNG_MAXSUM;
\r
2497 lmins = (lmhi << PNG_HISHIFT) + lmlo;
\r
2501 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
\r
2506 sum += (v < 128) ? v : 256 - v;
\r
2509 for (lp = row_buf + 1; i < row_bytes;
\r
2510 i++, rp++, lp++, dp++)
\r
2512 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
\r
2514 sum += (v < 128) ? v : 256 - v;
\r
2516 if (sum > lmins) /* We are already worse, don't continue. */
\r
2520 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2521 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2524 png_uint_32 sumhi, sumlo;
\r
2525 sumlo = sum & PNG_LOMASK;
\r
2526 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
\r
2528 for (j = 0; j < num_p_filters; j++)
\r
2530 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
\r
2532 sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
\r
2535 sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
\r
2540 sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
\r
2543 sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
\r
2546 if (sumhi > PNG_HIMASK)
\r
2550 sum = (sumhi << PNG_HISHIFT) + sumlo;
\r
2557 best_row = png_ptr->sub_row;
\r
2562 if (filter_to_do == PNG_FILTER_UP)
\r
2564 png_bytep rp, dp, pp;
\r
2567 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
\r
2568 pp = prev_row + 1; i < row_bytes;
\r
2569 i++, rp++, pp++, dp++)
\r
2571 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
\r
2574 best_row = png_ptr->up_row;
\r
2577 else if (filter_to_do & PNG_FILTER_UP)
\r
2579 png_bytep rp, dp, pp;
\r
2580 png_uint_32 sum = 0, lmins = mins;
\r
2585 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2586 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2589 png_uint_32 lmhi, lmlo;
\r
2590 lmlo = lmins & PNG_LOMASK;
\r
2591 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
\r
2593 for (j = 0; j < num_p_filters; j++)
\r
2595 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
\r
2597 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
\r
2600 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
\r
2605 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
\r
2608 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
\r
2611 if (lmhi > PNG_HIMASK)
\r
2612 lmins = PNG_MAXSUM;
\r
2615 lmins = (lmhi << PNG_HISHIFT) + lmlo;
\r
2619 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
\r
2620 pp = prev_row + 1; i < row_bytes; i++)
\r
2622 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
\r
2624 sum += (v < 128) ? v : 256 - v;
\r
2626 if (sum > lmins) /* We are already worse, don't continue. */
\r
2630 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2631 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2634 png_uint_32 sumhi, sumlo;
\r
2635 sumlo = sum & PNG_LOMASK;
\r
2636 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
\r
2638 for (j = 0; j < num_p_filters; j++)
\r
2640 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
\r
2642 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
\r
2645 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
\r
2650 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
\r
2653 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
\r
2656 if (sumhi > PNG_HIMASK)
\r
2660 sum = (sumhi << PNG_HISHIFT) + sumlo;
\r
2667 best_row = png_ptr->up_row;
\r
2672 if (filter_to_do == PNG_FILTER_AVG)
\r
2674 png_bytep rp, dp, pp, lp;
\r
2677 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
\r
2678 pp = prev_row + 1; i < bpp; i++)
\r
2680 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
\r
2683 for (lp = row_buf + 1; i < row_bytes; i++)
\r
2685 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
\r
2688 best_row = png_ptr->avg_row;
\r
2691 else if (filter_to_do & PNG_FILTER_AVG)
\r
2693 png_bytep rp, dp, pp, lp;
\r
2694 png_uint_32 sum = 0, lmins = mins;
\r
2698 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2699 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2702 png_uint_32 lmhi, lmlo;
\r
2703 lmlo = lmins & PNG_LOMASK;
\r
2704 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
\r
2706 for (j = 0; j < num_p_filters; j++)
\r
2708 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
\r
2710 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
\r
2713 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
\r
2718 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
\r
2721 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
\r
2724 if (lmhi > PNG_HIMASK)
\r
2725 lmins = PNG_MAXSUM;
\r
2728 lmins = (lmhi << PNG_HISHIFT) + lmlo;
\r
2732 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
\r
2733 pp = prev_row + 1; i < bpp; i++)
\r
2735 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
\r
2737 sum += (v < 128) ? v : 256 - v;
\r
2740 for (lp = row_buf + 1; i < row_bytes; i++)
\r
2743 (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
\r
2745 sum += (v < 128) ? v : 256 - v;
\r
2747 if (sum > lmins) /* We are already worse, don't continue. */
\r
2751 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2752 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2755 png_uint_32 sumhi, sumlo;
\r
2756 sumlo = sum & PNG_LOMASK;
\r
2757 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
\r
2759 for (j = 0; j < num_p_filters; j++)
\r
2761 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
\r
2763 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
\r
2766 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
\r
2771 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
\r
2774 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
\r
2777 if (sumhi > PNG_HIMASK)
\r
2781 sum = (sumhi << PNG_HISHIFT) + sumlo;
\r
2788 best_row = png_ptr->avg_row;
\r
2792 /* Paeth filter */
\r
2793 if (filter_to_do == PNG_FILTER_PAETH)
\r
2795 png_bytep rp, dp, pp, cp, lp;
\r
2798 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
\r
2799 pp = prev_row + 1; i < bpp; i++)
\r
2801 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
\r
2804 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
\r
2806 int a, b, c, pa, pb, pc, p;
\r
2815 #ifdef PNG_USE_ABS
\r
2820 pa = p < 0 ? -p : p;
\r
2821 pb = pc < 0 ? -pc : pc;
\r
2822 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
\r
2825 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
\r
2827 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
\r
2829 best_row = png_ptr->paeth_row;
\r
2832 else if (filter_to_do & PNG_FILTER_PAETH)
\r
2834 png_bytep rp, dp, pp, cp, lp;
\r
2835 png_uint_32 sum = 0, lmins = mins;
\r
2839 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2840 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2843 png_uint_32 lmhi, lmlo;
\r
2844 lmlo = lmins & PNG_LOMASK;
\r
2845 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
\r
2847 for (j = 0; j < num_p_filters; j++)
\r
2849 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
\r
2851 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
\r
2854 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
\r
2859 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
\r
2862 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
\r
2865 if (lmhi > PNG_HIMASK)
\r
2866 lmins = PNG_MAXSUM;
\r
2869 lmins = (lmhi << PNG_HISHIFT) + lmlo;
\r
2873 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
\r
2874 pp = prev_row + 1; i < bpp; i++)
\r
2876 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
\r
2878 sum += (v < 128) ? v : 256 - v;
\r
2881 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
\r
2883 int a, b, c, pa, pb, pc, p;
\r
2889 #ifndef PNG_SLOW_PAETH
\r
2892 #ifdef PNG_USE_ABS
\r
2897 pa = p < 0 ? -p : p;
\r
2898 pb = pc < 0 ? -pc : pc;
\r
2899 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
\r
2901 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
\r
2902 #else /* PNG_SLOW_PAETH */
\r
2908 if (pa <= pb && pa <= pc)
\r
2911 else if (pb <= pc)
\r
2916 #endif /* PNG_SLOW_PAETH */
\r
2918 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
\r
2920 sum += (v < 128) ? v : 256 - v;
\r
2922 if (sum > lmins) /* We are already worse, don't continue. */
\r
2926 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2927 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
\r
2930 png_uint_32 sumhi, sumlo;
\r
2931 sumlo = sum & PNG_LOMASK;
\r
2932 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
\r
2934 for (j = 0; j < num_p_filters; j++)
\r
2936 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
\r
2938 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
\r
2941 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
\r
2946 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
\r
2949 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
\r
2952 if (sumhi > PNG_HIMASK)
\r
2956 sum = (sumhi << PNG_HISHIFT) + sumlo;
\r
2962 best_row = png_ptr->paeth_row;
\r
2965 #endif /* PNG_WRITE_FILTER_SUPPORTED */
\r
2967 /* Do the actual writing of the filtered row data from the chosen filter. */
\r
2968 png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
\r
2970 #ifdef PNG_WRITE_FILTER_SUPPORTED
\r
2971 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
\r
2972 /* Save the type of filter we picked this time for future calculations */
\r
2973 if (png_ptr->num_prev_filters > 0)
\r
2977 for (j = 1; j < num_p_filters; j++)
\r
2979 png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
\r
2982 png_ptr->prev_filters[j] = best_row[0];
\r
2985 #endif /* PNG_WRITE_FILTER_SUPPORTED */
\r
2989 /* Do the actual writing of a previously filtered row. */
\r
2991 png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
\r
2992 png_size_t full_row_length/*includes filter byte*/)
\r
2994 png_debug(1, "in png_write_filtered_row");
\r
2996 png_debug1(2, "filter = %d", filtered_row[0]);
\r
2998 png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
\r
3000 /* Swap the current and previous rows */
\r
3001 if (png_ptr->prev_row != NULL)
\r
3005 tptr = png_ptr->prev_row;
\r
3006 png_ptr->prev_row = png_ptr->row_buf;
\r
3007 png_ptr->row_buf = tptr;
\r
3010 /* Finish row - updates counters and flushes zlib if last row */
\r
3011 png_write_finish_row(png_ptr);
\r
3013 #ifdef PNG_WRITE_FLUSH_SUPPORTED
\r
3014 png_ptr->flush_rows++;
\r
3016 if (png_ptr->flush_dist > 0 &&
\r
3017 png_ptr->flush_rows >= png_ptr->flush_dist)
\r
3019 png_write_flush(png_ptr);
\r
3023 #endif /* PNG_WRITE_SUPPORTED */
\r
3024 #endif//_FPDFAPI_MINI_
\r