2 /* pngwutil.c - utilities to write a PNG file
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4 * Copyright (c) 2018 Cosmin Truta
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5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
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6 * Copyright (c) 1996-1997 Andreas Dilger
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7 * 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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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) & 0xffU);
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27 buf[1] = (png_byte)((i >> 16) & 0xffU);
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28 buf[2] = (png_byte)((i >> 8) & 0xffU);
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29 buf[3] = (png_byte)( i & 0xffU);
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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) & 0xffU);
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40 buf[1] = (png_byte)( i & 0xffU);
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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 (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, size_t length)
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129 /* Write the data, and run the CRC over it */
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130 if (png_ptr == NULL)
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133 if (data != NULL && length > 0)
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135 png_write_data(png_ptr, data, length);
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137 /* Update the CRC after writing the data,
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138 * in case the user I/O routine alters it.
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140 png_calculate_crc(png_ptr, data, length);
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144 /* Finish a chunk started with png_write_chunk_header(). */
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146 png_write_chunk_end(png_structrp png_ptr)
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150 if (png_ptr == NULL) return;
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152 #ifdef PNG_IO_STATE_SUPPORTED
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153 /* Inform the I/O callback that the chunk CRC is being written.
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154 * PNG_IO_CHUNK_CRC requires a single I/O function call.
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156 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
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159 /* Write the crc in a single operation */
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160 png_save_uint_32(buf, png_ptr->crc);
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162 png_write_data(png_ptr, buf, 4);
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165 /* Write a PNG chunk all at once. The type is an array of ASCII characters
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166 * representing the chunk name. The array must be at least 4 bytes in
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167 * length, and does not need to be null terminated. To be safe, pass the
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168 * pre-defined chunk names here, and if you need a new one, define it
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169 * where the others are defined. The length is the length of the data.
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170 * All the data must be present. If that is not possible, use the
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171 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
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172 * functions instead.
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175 png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
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176 png_const_bytep data, size_t length)
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178 if (png_ptr == NULL)
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181 /* On 64-bit architectures 'length' may not fit in a png_uint_32. */
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182 if (length > PNG_UINT_31_MAX)
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183 png_error(png_ptr, "length exceeds PNG maximum");
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185 png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
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186 png_write_chunk_data(png_ptr, data, length);
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187 png_write_chunk_end(png_ptr);
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190 /* This is the API that calls the internal function above. */
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192 png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
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193 png_const_bytep data, size_t length)
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195 png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
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199 /* This is used below to find the size of an image to pass to png_deflate_claim,
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200 * so it only needs to be accurate if the size is less than 16384 bytes (the
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201 * point at which a lower LZ window size can be used.)
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203 static png_alloc_size_t
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204 png_image_size(png_structrp png_ptr)
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206 /* Only return sizes up to the maximum of a png_uint_32; do this by limiting
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207 * the width and height used to 15 bits.
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209 png_uint_32 h = png_ptr->height;
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211 if (png_ptr->rowbytes < 32768 && h < 32768)
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213 if (png_ptr->interlaced != 0)
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215 /* Interlacing makes the image larger because of the replication of
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216 * both the filter byte and the padding to a byte boundary.
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218 png_uint_32 w = png_ptr->width;
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219 unsigned int pd = png_ptr->pixel_depth;
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220 png_alloc_size_t cb_base;
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223 for (cb_base=0, pass=0; pass<=6; ++pass)
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225 png_uint_32 pw = PNG_PASS_COLS(w, pass);
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228 cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);
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235 return (png_ptr->rowbytes+1) * h;
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239 return 0xffffffffU;
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242 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
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243 /* This is the code to hack the first two bytes of the deflate stream (the
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244 * deflate header) to correct the windowBits value to match the actual data
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245 * size. Note that the second argument is the *uncompressed* size but the
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246 * first argument is the *compressed* data (and it must be deflate
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250 optimize_cmf(png_bytep data, png_alloc_size_t data_size)
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252 /* Optimize the CMF field in the zlib stream. The resultant zlib stream is
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253 * still compliant to the stream specification.
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255 if (data_size <= 16384) /* else windowBits must be 15 */
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257 unsigned int z_cmf = data[0]; /* zlib compression method and flags */
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259 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
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261 unsigned int z_cinfo;
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262 unsigned int half_z_window_size;
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264 z_cinfo = z_cmf >> 4;
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265 half_z_window_size = 1U << (z_cinfo + 7);
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267 if (data_size <= half_z_window_size) /* else no change */
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273 half_z_window_size >>= 1;
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276 while (z_cinfo > 0 && data_size <= half_z_window_size);
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278 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
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280 data[0] = (png_byte)z_cmf;
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281 tmp = data[1] & 0xe0;
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282 tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
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283 data[1] = (png_byte)tmp;
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288 #endif /* WRITE_OPTIMIZE_CMF */
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290 /* Initialize the compressor for the appropriate type of compression. */
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292 png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
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293 png_alloc_size_t data_size)
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295 if (png_ptr->zowner != 0)
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297 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
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300 PNG_STRING_FROM_CHUNK(msg, owner);
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303 PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);
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304 /* So the message that results is "<chunk> using zstream"; this is an
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305 * internal error, but is very useful for debugging. i18n requirements
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308 (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
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310 #if PNG_RELEASE_BUILD
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311 png_warning(png_ptr, msg);
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313 /* Attempt sane error recovery */
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314 if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */
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316 png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");
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317 return Z_STREAM_ERROR;
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320 png_ptr->zowner = 0;
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322 png_error(png_ptr, msg);
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327 int level = png_ptr->zlib_level;
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328 int method = png_ptr->zlib_method;
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329 int windowBits = png_ptr->zlib_window_bits;
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330 int memLevel = png_ptr->zlib_mem_level;
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331 int strategy; /* set below */
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332 int ret; /* zlib return code */
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334 if (owner == png_IDAT)
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336 if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
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337 strategy = png_ptr->zlib_strategy;
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339 else if (png_ptr->do_filter != PNG_FILTER_NONE)
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340 strategy = PNG_Z_DEFAULT_STRATEGY;
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343 strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;
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348 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
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349 level = png_ptr->zlib_text_level;
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350 method = png_ptr->zlib_text_method;
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351 windowBits = png_ptr->zlib_text_window_bits;
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352 memLevel = png_ptr->zlib_text_mem_level;
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353 strategy = png_ptr->zlib_text_strategy;
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355 /* If customization is not supported the values all come from the
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356 * IDAT values except for the strategy, which is fixed to the
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357 * default. (This is the pre-1.6.0 behavior too, although it was
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358 * implemented in a very different way.)
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360 strategy = Z_DEFAULT_STRATEGY;
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364 /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
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365 * happening just pass 32768 as the data_size parameter. Notice that zlib
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366 * requires an extra 262 bytes in the window in addition to the data to be
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367 * able to see the whole of the data, so if data_size+262 takes us to the
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368 * next windowBits size we need to fix up the value later. (Because even
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369 * though deflate needs the extra window, inflate does not!)
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371 if (data_size <= 16384)
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373 /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to
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374 * work round a Microsoft Visual C misbehavior which, contrary to C-90,
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375 * widens the result of the following shift to 64-bits if (and,
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376 * apparently, only if) it is used in a test.
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378 unsigned int half_window_size = 1U << (windowBits-1);
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380 while (data_size + 262 <= half_window_size)
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382 half_window_size >>= 1;
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387 /* Check against the previous initialized values, if any. */
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388 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
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389 (png_ptr->zlib_set_level != level ||
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390 png_ptr->zlib_set_method != method ||
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391 png_ptr->zlib_set_window_bits != windowBits ||
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392 png_ptr->zlib_set_mem_level != memLevel ||
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393 png_ptr->zlib_set_strategy != strategy))
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395 if (deflateEnd(&png_ptr->zstream) != Z_OK)
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396 png_warning(png_ptr, "deflateEnd failed (ignored)");
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398 png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;
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401 /* For safety clear out the input and output pointers (currently zlib
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402 * doesn't use them on Init, but it might in the future).
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404 png_ptr->zstream.next_in = NULL;
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405 png_ptr->zstream.avail_in = 0;
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406 png_ptr->zstream.next_out = NULL;
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407 png_ptr->zstream.avail_out = 0;
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409 /* Now initialize if required, setting the new parameters, otherwise just
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410 * do a simple reset to the previous parameters.
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412 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
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413 ret = deflateReset(&png_ptr->zstream);
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417 ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
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418 memLevel, strategy);
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421 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
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424 /* The return code is from either deflateReset or deflateInit2; they have
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425 * pretty much the same set of error codes.
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428 png_ptr->zowner = owner;
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431 png_zstream_error(png_ptr, ret);
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437 /* Clean up (or trim) a linked list of compression buffers. */
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439 png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)
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441 png_compression_bufferp list = *listp;
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449 png_compression_bufferp next = list->next;
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451 png_free(png_ptr, list);
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454 while (list != NULL);
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458 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
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459 /* This pair of functions encapsulates the operation of (a) compressing a
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460 * text string, and (b) issuing it later as a series of chunk data writes.
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461 * The compression_state structure is shared context for these functions
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462 * set up by the caller to allow access to the relevant local variables.
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464 * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size
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465 * temporary buffers. From 1.6.0 it is retained in png_struct so that it will
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466 * be correctly freed in the event of a write error (previous implementations
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467 * just leaked memory.)
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471 png_const_bytep input; /* The uncompressed input data */
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472 png_alloc_size_t input_len; /* Its length */
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473 png_uint_32 output_len; /* Final compressed length */
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474 png_byte output[1024]; /* First block of output */
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475 } compression_state;
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478 png_text_compress_init(compression_state *comp, png_const_bytep input,
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479 png_alloc_size_t input_len)
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481 comp->input = input;
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482 comp->input_len = input_len;
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483 comp->output_len = 0;
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486 /* Compress the data in the compression state input */
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488 png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
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489 compression_state *comp, png_uint_32 prefix_len)
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493 /* To find the length of the output it is necessary to first compress the
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494 * input. The result is buffered rather than using the two-pass algorithm
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495 * that is used on the inflate side; deflate is assumed to be slower and a
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496 * PNG writer is assumed to have more memory available than a PNG reader.
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498 * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an
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499 * upper limit on the output size, but it is always bigger than the input
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500 * size so it is likely to be more efficient to use this linked-list
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503 ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);
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508 /* Set up the compression buffers, we need a loop here to avoid overflowing a
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509 * uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited
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510 * by the output buffer size, so there is no need to check that. Since this
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511 * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits
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515 png_compression_bufferp *end = &png_ptr->zbuffer_list;
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516 png_alloc_size_t input_len = comp->input_len; /* may be zero! */
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517 png_uint_32 output_len;
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519 /* zlib updates these for us: */
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520 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);
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521 png_ptr->zstream.avail_in = 0; /* Set below */
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522 png_ptr->zstream.next_out = comp->output;
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523 png_ptr->zstream.avail_out = (sizeof comp->output);
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525 output_len = png_ptr->zstream.avail_out;
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529 uInt avail_in = ZLIB_IO_MAX;
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531 if (avail_in > input_len)
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532 avail_in = (uInt)input_len;
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534 input_len -= avail_in;
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536 png_ptr->zstream.avail_in = avail_in;
\r
538 if (png_ptr->zstream.avail_out == 0)
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540 png_compression_buffer *next;
\r
542 /* Chunk data is limited to 2^31 bytes in length, so the prefix
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543 * length must be counted here.
\r
545 if (output_len + prefix_len > PNG_UINT_31_MAX)
\r
551 /* Need a new (malloc'ed) buffer, but there may be one present
\r
557 next = png_voidcast(png_compression_bufferp, png_malloc_base
\r
558 (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
\r
566 /* Link in this buffer (so that it will be freed later) */
\r
571 png_ptr->zstream.next_out = next->output;
\r
572 png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
\r
573 output_len += png_ptr->zstream.avail_out;
\r
575 /* Move 'end' to the next buffer pointer. */
\r
579 /* Compress the data */
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580 ret = deflate(&png_ptr->zstream,
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581 input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
\r
583 /* Claw back input data that was not consumed (because avail_in is
\r
584 * reset above every time round the loop).
\r
586 input_len += png_ptr->zstream.avail_in;
\r
587 png_ptr->zstream.avail_in = 0; /* safety */
\r
589 while (ret == Z_OK);
\r
591 /* There may be some space left in the last output buffer. This needs to
\r
592 * be subtracted from output_len.
\r
594 output_len -= png_ptr->zstream.avail_out;
\r
595 png_ptr->zstream.avail_out = 0; /* safety */
\r
596 comp->output_len = output_len;
\r
598 /* Now double check the output length, put in a custom message if it is
\r
599 * too long. Otherwise ensure the z_stream::msg pointer is set to
\r
602 if (output_len + prefix_len >= PNG_UINT_31_MAX)
\r
604 png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");
\r
609 png_zstream_error(png_ptr, ret);
\r
611 /* Reset zlib for another zTXt/iTXt or image data */
\r
612 png_ptr->zowner = 0;
\r
614 /* The only success case is Z_STREAM_END, input_len must be 0; if not this
\r
615 * is an internal error.
\r
617 if (ret == Z_STREAM_END && input_len == 0)
\r
619 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
\r
620 /* Fix up the deflate header, if required */
\r
621 optimize_cmf(comp->output, comp->input_len);
\r
623 /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
\r
624 * function above to return Z_STREAM_END on an error (though it never
\r
625 * does in the current versions of zlib.)
\r
635 /* Ship the compressed text out via chunk writes */
\r
637 png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
\r
639 png_uint_32 output_len = comp->output_len;
\r
640 png_const_bytep output = comp->output;
\r
641 png_uint_32 avail = (sizeof comp->output);
\r
642 png_compression_buffer *next = png_ptr->zbuffer_list;
\r
646 if (avail > output_len)
\r
647 avail = output_len;
\r
649 png_write_chunk_data(png_ptr, output, avail);
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651 output_len -= avail;
\r
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! */
\r
662 if (output_len > 0)
\r
663 png_error(png_ptr, "error writing ancillary chunked compressed data");
\r
665 #endif /* WRITE_COMPRESSED_TEXT */
\r
667 /* Write the IHDR chunk, and update the png_struct with the necessary
\r
668 * information. Note that the rest of this code depends upon this
\r
669 * information being correct.
\r
672 png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
\r
673 int bit_depth, int color_type, int compression_type, int filter_type,
\r
674 int interlace_type)
\r
676 png_byte buf[13]; /* Buffer to store the IHDR info */
\r
677 int is_invalid_depth;
\r
679 png_debug(1, "in png_write_IHDR");
\r
681 /* Check that we have valid input data from the application info */
\r
682 switch (color_type)
\r
684 case PNG_COLOR_TYPE_GRAY:
\r
691 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
694 png_ptr->channels = 1; break;
\r
698 "Invalid bit depth for grayscale image");
\r
702 case PNG_COLOR_TYPE_RGB:
\r
703 is_invalid_depth = (bit_depth != 8);
\r
704 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
705 is_invalid_depth = (is_invalid_depth && bit_depth != 16);
\r
707 if (is_invalid_depth)
\r
708 png_error(png_ptr, "Invalid bit depth for RGB image");
\r
710 png_ptr->channels = 3;
\r
713 case PNG_COLOR_TYPE_PALETTE:
\r
720 png_ptr->channels = 1;
\r
724 png_error(png_ptr, "Invalid bit depth for paletted image");
\r
728 case PNG_COLOR_TYPE_GRAY_ALPHA:
\r
729 is_invalid_depth = (bit_depth != 8);
\r
730 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
731 is_invalid_depth = (is_invalid_depth && bit_depth != 16);
\r
733 if (is_invalid_depth)
\r
734 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
\r
736 png_ptr->channels = 2;
\r
739 case PNG_COLOR_TYPE_RGB_ALPHA:
\r
740 is_invalid_depth = (bit_depth != 8);
\r
741 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
742 is_invalid_depth = (is_invalid_depth && bit_depth != 16);
\r
744 if (is_invalid_depth)
\r
745 png_error(png_ptr, "Invalid bit depth for RGBA image");
\r
747 png_ptr->channels = 4;
\r
751 png_error(png_ptr, "Invalid image color type specified");
\r
754 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
\r
756 png_warning(png_ptr, "Invalid compression type specified");
\r
757 compression_type = PNG_COMPRESSION_TYPE_BASE;
\r
760 /* Write filter_method 64 (intrapixel differencing) only if
\r
761 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
\r
762 * 2. Libpng did not write a PNG signature (this filter_method is only
\r
763 * used in PNG datastreams that are embedded in MNG datastreams) and
\r
764 * 3. The application called png_permit_mng_features with a mask that
\r
765 * included PNG_FLAG_MNG_FILTER_64 and
\r
766 * 4. The filter_method is 64 and
\r
767 * 5. The color_type is RGB or RGBA
\r
770 #ifdef PNG_MNG_FEATURES_SUPPORTED
\r
771 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
\r
772 ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
\r
773 (color_type == PNG_COLOR_TYPE_RGB ||
\r
774 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
\r
775 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
\r
777 filter_type != PNG_FILTER_TYPE_BASE)
\r
779 png_warning(png_ptr, "Invalid filter type specified");
\r
780 filter_type = PNG_FILTER_TYPE_BASE;
\r
783 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
784 if (interlace_type != PNG_INTERLACE_NONE &&
\r
785 interlace_type != PNG_INTERLACE_ADAM7)
\r
787 png_warning(png_ptr, "Invalid interlace type specified");
\r
788 interlace_type = PNG_INTERLACE_ADAM7;
\r
791 interlace_type=PNG_INTERLACE_NONE;
\r
794 /* Save the relevant information */
\r
795 png_ptr->bit_depth = (png_byte)bit_depth;
\r
796 png_ptr->color_type = (png_byte)color_type;
\r
797 png_ptr->interlaced = (png_byte)interlace_type;
\r
798 #ifdef PNG_MNG_FEATURES_SUPPORTED
\r
799 png_ptr->filter_type = (png_byte)filter_type;
\r
801 png_ptr->compression_type = (png_byte)compression_type;
\r
802 png_ptr->width = width;
\r
803 png_ptr->height = height;
\r
805 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
\r
806 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
\r
807 /* Set the usr info, so any transformations can modify it */
\r
808 png_ptr->usr_width = png_ptr->width;
\r
809 png_ptr->usr_bit_depth = png_ptr->bit_depth;
\r
810 png_ptr->usr_channels = png_ptr->channels;
\r
812 /* Pack the header information into the buffer */
\r
813 png_save_uint_32(buf, width);
\r
814 png_save_uint_32(buf + 4, height);
\r
815 buf[8] = (png_byte)bit_depth;
\r
816 buf[9] = (png_byte)color_type;
\r
817 buf[10] = (png_byte)compression_type;
\r
818 buf[11] = (png_byte)filter_type;
\r
819 buf[12] = (png_byte)interlace_type;
\r
821 /* Write the chunk */
\r
822 png_write_complete_chunk(png_ptr, png_IHDR, buf, 13);
\r
824 if ((png_ptr->do_filter) == PNG_NO_FILTERS)
\r
826 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
\r
827 png_ptr->bit_depth < 8)
\r
828 png_ptr->do_filter = PNG_FILTER_NONE;
\r
831 png_ptr->do_filter = PNG_ALL_FILTERS;
\r
834 png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
\r
837 /* Write the palette. We are careful not to trust png_color to be in the
\r
838 * correct order for PNG, so people can redefine it to any convenient
\r
842 png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
\r
843 png_uint_32 num_pal)
\r
845 png_uint_32 max_palette_length, i;
\r
846 png_const_colorp pal_ptr;
\r
849 png_debug(1, "in png_write_PLTE");
\r
851 max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
\r
852 (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
\r
855 #ifdef PNG_MNG_FEATURES_SUPPORTED
\r
856 (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
\r
858 num_pal == 0) || num_pal > max_palette_length)
\r
860 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
\r
862 png_error(png_ptr, "Invalid number of colors in palette");
\r
867 png_warning(png_ptr, "Invalid number of colors in palette");
\r
872 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
\r
874 png_warning(png_ptr,
\r
875 "Ignoring request to write a PLTE chunk in grayscale PNG");
\r
880 png_ptr->num_palette = (png_uint_16)num_pal;
\r
881 png_debug1(3, "num_palette = %d", png_ptr->num_palette);
\r
883 png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
\r
884 #ifdef PNG_POINTER_INDEXING_SUPPORTED
\r
886 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
\r
888 buf[0] = pal_ptr->red;
\r
889 buf[1] = pal_ptr->green;
\r
890 buf[2] = pal_ptr->blue;
\r
891 png_write_chunk_data(png_ptr, buf, 3);
\r
895 /* This is a little slower but some buggy compilers need to do this
\r
900 for (i = 0; i < num_pal; i++)
\r
902 buf[0] = pal_ptr[i].red;
\r
903 buf[1] = pal_ptr[i].green;
\r
904 buf[2] = pal_ptr[i].blue;
\r
905 png_write_chunk_data(png_ptr, buf, 3);
\r
909 png_write_chunk_end(png_ptr);
\r
910 png_ptr->mode |= PNG_HAVE_PLTE;
\r
913 /* This is similar to png_text_compress, above, except that it does not require
\r
914 * all of the data at once and, instead of buffering the compressed result,
\r
915 * writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out
\r
916 * because it calls the write interface. As a result it does its own error
\r
917 * reporting and does not return an error code. In the event of error it will
\r
918 * just call png_error. The input data length may exceed 32-bits. The 'flush'
\r
919 * parameter is exactly the same as that to deflate, with the following
\r
922 * Z_NO_FLUSH: normal incremental output of compressed data
\r
923 * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush
\r
924 * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
\r
926 * The routine manages the acquire and release of the png_ptr->zstream by
\r
927 * checking and (at the end) clearing png_ptr->zowner; it does some sanity
\r
928 * checks on the 'mode' flags while doing this.
\r
931 png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
\r
932 png_alloc_size_t input_len, int flush)
\r
934 if (png_ptr->zowner != png_IDAT)
\r
936 /* First time. Ensure we have a temporary buffer for compression and
\r
937 * trim the buffer list if it has more than one entry to free memory.
\r
938 * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been
\r
939 * created at this point, but the check here is quick and safe.
\r
941 if (png_ptr->zbuffer_list == NULL)
\r
943 png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,
\r
944 png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
\r
945 png_ptr->zbuffer_list->next = NULL;
\r
949 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);
\r
951 /* It is a terminal error if we can't claim the zstream. */
\r
952 if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)
\r
953 png_error(png_ptr, png_ptr->zstream.msg);
\r
955 /* The output state is maintained in png_ptr->zstream, so it must be
\r
956 * initialized here after the claim.
\r
958 png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;
\r
959 png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
\r
962 /* Now loop reading and writing until all the input is consumed or an error
\r
963 * terminates the operation. The _out values are maintained across calls to
\r
964 * this function, but the input must be reset each time.
\r
966 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
\r
967 png_ptr->zstream.avail_in = 0; /* set below */
\r
972 /* INPUT: from the row data */
\r
973 uInt avail = ZLIB_IO_MAX;
\r
975 if (avail > input_len)
\r
976 avail = (uInt)input_len; /* safe because of the check */
\r
978 png_ptr->zstream.avail_in = avail;
\r
979 input_len -= avail;
\r
981 ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);
\r
983 /* Include as-yet unconsumed input */
\r
984 input_len += png_ptr->zstream.avail_in;
\r
985 png_ptr->zstream.avail_in = 0;
\r
987 /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note
\r
988 * that these two zstream fields are preserved across the calls, therefore
\r
989 * there is no need to set these up on entry to the loop.
\r
991 if (png_ptr->zstream.avail_out == 0)
\r
993 png_bytep data = png_ptr->zbuffer_list->output;
\r
994 uInt size = png_ptr->zbuffer_size;
\r
996 /* Write an IDAT containing the data then reset the buffer. The
\r
997 * first IDAT may need deflate header optimization.
\r
999 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
\r
1000 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
\r
1001 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
\r
1002 optimize_cmf(data, png_image_size(png_ptr));
\r
1006 png_write_complete_chunk(png_ptr, png_IDAT, data, size);
\r
1007 png_ptr->mode |= PNG_HAVE_IDAT;
\r
1009 png_ptr->zstream.next_out = data;
\r
1010 png_ptr->zstream.avail_out = size;
\r
1012 /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with
\r
1013 * the same flush parameter until it has finished output, for NO_FLUSH
\r
1014 * it doesn't matter.
\r
1016 if (ret == Z_OK && flush != Z_NO_FLUSH)
\r
1020 /* The order of these checks doesn't matter much; it just affects which
\r
1021 * possible error might be detected if multiple things go wrong at once.
\r
1023 if (ret == Z_OK) /* most likely return code! */
\r
1025 /* If all the input has been consumed then just return. If Z_FINISH
\r
1026 * was used as the flush parameter something has gone wrong if we get
\r
1029 if (input_len == 0)
\r
1031 if (flush == Z_FINISH)
\r
1032 png_error(png_ptr, "Z_OK on Z_FINISH with output space");
\r
1038 else if (ret == Z_STREAM_END && flush == Z_FINISH)
\r
1040 /* This is the end of the IDAT data; any pending output must be
\r
1041 * flushed. For small PNG files we may still be at the beginning.
\r
1043 png_bytep data = png_ptr->zbuffer_list->output;
\r
1044 uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;
\r
1046 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
\r
1047 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
\r
1048 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
\r
1049 optimize_cmf(data, png_image_size(png_ptr));
\r
1053 png_write_complete_chunk(png_ptr, png_IDAT, data, size);
\r
1054 png_ptr->zstream.avail_out = 0;
\r
1055 png_ptr->zstream.next_out = NULL;
\r
1056 png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
\r
1058 png_ptr->zowner = 0; /* Release the stream */
\r
1064 /* This is an error condition. */
\r
1065 png_zstream_error(png_ptr, ret);
\r
1066 png_error(png_ptr, png_ptr->zstream.msg);
\r
1071 /* Write an IEND chunk */
\r
1072 void /* PRIVATE */
\r
1073 png_write_IEND(png_structrp png_ptr)
\r
1075 png_debug(1, "in png_write_IEND");
\r
1077 png_write_complete_chunk(png_ptr, png_IEND, NULL, 0);
\r
1078 png_ptr->mode |= PNG_HAVE_IEND;
\r
1081 #ifdef PNG_WRITE_gAMA_SUPPORTED
\r
1082 /* Write a gAMA chunk */
\r
1083 void /* PRIVATE */
\r
1084 png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)
\r
1088 png_debug(1, "in png_write_gAMA");
\r
1090 /* file_gamma is saved in 1/100,000ths */
\r
1091 png_save_uint_32(buf, (png_uint_32)file_gamma);
\r
1092 png_write_complete_chunk(png_ptr, png_gAMA, buf, 4);
\r
1096 #ifdef PNG_WRITE_sRGB_SUPPORTED
\r
1097 /* Write a sRGB chunk */
\r
1098 void /* PRIVATE */
\r
1099 png_write_sRGB(png_structrp png_ptr, int srgb_intent)
\r
1103 png_debug(1, "in png_write_sRGB");
\r
1105 if (srgb_intent >= PNG_sRGB_INTENT_LAST)
\r
1106 png_warning(png_ptr,
\r
1107 "Invalid sRGB rendering intent specified");
\r
1109 buf[0]=(png_byte)srgb_intent;
\r
1110 png_write_complete_chunk(png_ptr, png_sRGB, buf, 1);
\r
1114 #ifdef PNG_WRITE_iCCP_SUPPORTED
\r
1115 /* Write an iCCP chunk */
\r
1116 void /* PRIVATE */
\r
1117 png_write_iCCP(png_structrp png_ptr, png_const_charp name,
\r
1118 png_const_bytep profile)
\r
1120 png_uint_32 name_len;
\r
1121 png_uint_32 profile_len;
\r
1122 png_byte new_name[81]; /* 1 byte for the compression byte */
\r
1123 compression_state comp;
\r
1126 png_debug(1, "in png_write_iCCP");
\r
1128 /* These are all internal problems: the profile should have been checked
\r
1129 * before when it was stored.
\r
1131 if (profile == NULL)
\r
1132 png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
\r
1134 profile_len = png_get_uint_32(profile);
\r
1136 if (profile_len < 132)
\r
1137 png_error(png_ptr, "ICC profile too short");
\r
1139 temp = (png_uint_32) (*(profile+8));
\r
1140 if (temp > 3 && (profile_len & 0x03))
\r
1141 png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
\r
1144 png_uint_32 embedded_profile_len = png_get_uint_32(profile);
\r
1146 if (profile_len != embedded_profile_len)
\r
1147 png_error(png_ptr, "Profile length does not match profile");
\r
1150 name_len = png_check_keyword(png_ptr, name, new_name);
\r
1152 if (name_len == 0)
\r
1153 png_error(png_ptr, "iCCP: invalid keyword");
\r
1155 new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;
\r
1157 /* Make sure we include the NULL after the name and the compression type */
\r
1160 png_text_compress_init(&comp, profile, profile_len);
\r
1162 /* Allow for keyword terminator and compression byte */
\r
1163 if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)
\r
1164 png_error(png_ptr, png_ptr->zstream.msg);
\r
1166 png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);
\r
1168 png_write_chunk_data(png_ptr, new_name, name_len);
\r
1170 png_write_compressed_data_out(png_ptr, &comp);
\r
1172 png_write_chunk_end(png_ptr);
\r
1176 #ifdef PNG_WRITE_sPLT_SUPPORTED
\r
1177 /* Write a sPLT chunk */
\r
1178 void /* PRIVATE */
\r
1179 png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
\r
1181 png_uint_32 name_len;
\r
1182 png_byte new_name[80];
\r
1183 png_byte entrybuf[10];
\r
1184 size_t entry_size = (spalette->depth == 8 ? 6 : 10);
\r
1185 size_t palette_size = entry_size * (size_t)spalette->nentries;
\r
1186 png_sPLT_entryp ep;
\r
1187 #ifndef PNG_POINTER_INDEXING_SUPPORTED
\r
1191 png_debug(1, "in png_write_sPLT");
\r
1193 name_len = png_check_keyword(png_ptr, spalette->name, new_name);
\r
1195 if (name_len == 0)
\r
1196 png_error(png_ptr, "sPLT: invalid keyword");
\r
1198 /* Make sure we include the NULL after the name */
\r
1199 png_write_chunk_header(png_ptr, png_sPLT,
\r
1200 (png_uint_32)(name_len + 2 + palette_size));
\r
1202 png_write_chunk_data(png_ptr, (png_bytep)new_name, (size_t)(name_len + 1));
\r
1204 png_write_chunk_data(png_ptr, &spalette->depth, 1);
\r
1206 /* Loop through each palette entry, writing appropriately */
\r
1207 #ifdef PNG_POINTER_INDEXING_SUPPORTED
\r
1208 for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
\r
1210 if (spalette->depth == 8)
\r
1212 entrybuf[0] = (png_byte)ep->red;
\r
1213 entrybuf[1] = (png_byte)ep->green;
\r
1214 entrybuf[2] = (png_byte)ep->blue;
\r
1215 entrybuf[3] = (png_byte)ep->alpha;
\r
1216 png_save_uint_16(entrybuf + 4, ep->frequency);
\r
1221 png_save_uint_16(entrybuf + 0, ep->red);
\r
1222 png_save_uint_16(entrybuf + 2, ep->green);
\r
1223 png_save_uint_16(entrybuf + 4, ep->blue);
\r
1224 png_save_uint_16(entrybuf + 6, ep->alpha);
\r
1225 png_save_uint_16(entrybuf + 8, ep->frequency);
\r
1228 png_write_chunk_data(png_ptr, entrybuf, entry_size);
\r
1231 ep=spalette->entries;
\r
1232 for (i = 0; i>spalette->nentries; i++)
\r
1234 if (spalette->depth == 8)
\r
1236 entrybuf[0] = (png_byte)ep[i].red;
\r
1237 entrybuf[1] = (png_byte)ep[i].green;
\r
1238 entrybuf[2] = (png_byte)ep[i].blue;
\r
1239 entrybuf[3] = (png_byte)ep[i].alpha;
\r
1240 png_save_uint_16(entrybuf + 4, ep[i].frequency);
\r
1245 png_save_uint_16(entrybuf + 0, ep[i].red);
\r
1246 png_save_uint_16(entrybuf + 2, ep[i].green);
\r
1247 png_save_uint_16(entrybuf + 4, ep[i].blue);
\r
1248 png_save_uint_16(entrybuf + 6, ep[i].alpha);
\r
1249 png_save_uint_16(entrybuf + 8, ep[i].frequency);
\r
1252 png_write_chunk_data(png_ptr, entrybuf, entry_size);
\r
1256 png_write_chunk_end(png_ptr);
\r
1260 #ifdef PNG_WRITE_sBIT_SUPPORTED
\r
1261 /* Write the sBIT chunk */
\r
1262 void /* PRIVATE */
\r
1263 png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
\r
1268 png_debug(1, "in png_write_sBIT");
\r
1270 /* Make sure we don't depend upon the order of PNG_COLOR_8 */
\r
1271 if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
\r
1275 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
\r
1276 png_ptr->usr_bit_depth);
\r
1278 if (sbit->red == 0 || sbit->red > maxbits ||
\r
1279 sbit->green == 0 || sbit->green > maxbits ||
\r
1280 sbit->blue == 0 || sbit->blue > maxbits)
\r
1282 png_warning(png_ptr, "Invalid sBIT depth specified");
\r
1286 buf[0] = sbit->red;
\r
1287 buf[1] = sbit->green;
\r
1288 buf[2] = sbit->blue;
\r
1294 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
\r
1296 png_warning(png_ptr, "Invalid sBIT depth specified");
\r
1300 buf[0] = sbit->gray;
\r
1304 if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
\r
1306 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
\r
1308 png_warning(png_ptr, "Invalid sBIT depth specified");
\r
1312 buf[size++] = sbit->alpha;
\r
1315 png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
\r
1319 #ifdef PNG_WRITE_cHRM_SUPPORTED
\r
1320 /* Write the cHRM chunk */
\r
1321 void /* PRIVATE */
\r
1322 png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)
\r
1326 png_debug(1, "in png_write_cHRM");
\r
1328 /* Each value is saved in 1/100,000ths */
\r
1329 png_save_int_32(buf, xy->whitex);
\r
1330 png_save_int_32(buf + 4, xy->whitey);
\r
1332 png_save_int_32(buf + 8, xy->redx);
\r
1333 png_save_int_32(buf + 12, xy->redy);
\r
1335 png_save_int_32(buf + 16, xy->greenx);
\r
1336 png_save_int_32(buf + 20, xy->greeny);
\r
1338 png_save_int_32(buf + 24, xy->bluex);
\r
1339 png_save_int_32(buf + 28, xy->bluey);
\r
1341 png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);
\r
1345 #ifdef PNG_WRITE_tRNS_SUPPORTED
\r
1346 /* Write the tRNS chunk */
\r
1347 void /* PRIVATE */
\r
1348 png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
\r
1349 png_const_color_16p tran, int num_trans, int color_type)
\r
1353 png_debug(1, "in png_write_tRNS");
\r
1355 if (color_type == PNG_COLOR_TYPE_PALETTE)
\r
1357 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
\r
1359 png_app_warning(png_ptr,
\r
1360 "Invalid number of transparent colors specified");
\r
1364 /* Write the chunk out as it is */
\r
1365 png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
\r
1366 (size_t)num_trans);
\r
1369 else if (color_type == PNG_COLOR_TYPE_GRAY)
\r
1371 /* One 16-bit value */
\r
1372 if (tran->gray >= (1 << png_ptr->bit_depth))
\r
1374 png_app_warning(png_ptr,
\r
1375 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
\r
1380 png_save_uint_16(buf, tran->gray);
\r
1381 png_write_complete_chunk(png_ptr, png_tRNS, buf, 2);
\r
1384 else if (color_type == PNG_COLOR_TYPE_RGB)
\r
1386 /* Three 16-bit values */
\r
1387 png_save_uint_16(buf, tran->red);
\r
1388 png_save_uint_16(buf + 2, tran->green);
\r
1389 png_save_uint_16(buf + 4, tran->blue);
\r
1390 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
1391 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
\r
1393 if ((buf[0] | buf[2] | buf[4]) != 0)
\r
1396 png_app_warning(png_ptr,
\r
1397 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
\r
1401 png_write_complete_chunk(png_ptr, png_tRNS, buf, 6);
\r
1406 png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
\r
1411 #ifdef PNG_WRITE_bKGD_SUPPORTED
\r
1412 /* Write the background chunk */
\r
1413 void /* PRIVATE */
\r
1414 png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
\r
1418 png_debug(1, "in png_write_bKGD");
\r
1420 if (color_type == PNG_COLOR_TYPE_PALETTE)
\r
1423 #ifdef PNG_MNG_FEATURES_SUPPORTED
\r
1424 (png_ptr->num_palette != 0 ||
\r
1425 (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
\r
1427 back->index >= png_ptr->num_palette)
\r
1429 png_warning(png_ptr, "Invalid background palette index");
\r
1433 buf[0] = back->index;
\r
1434 png_write_complete_chunk(png_ptr, png_bKGD, buf, 1);
\r
1437 else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
\r
1439 png_save_uint_16(buf, back->red);
\r
1440 png_save_uint_16(buf + 2, back->green);
\r
1441 png_save_uint_16(buf + 4, back->blue);
\r
1442 #ifdef PNG_WRITE_16BIT_SUPPORTED
\r
1443 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
\r
1445 if ((buf[0] | buf[2] | buf[4]) != 0)
\r
1448 png_warning(png_ptr,
\r
1449 "Ignoring attempt to write 16-bit bKGD chunk "
\r
1450 "when bit_depth is 8");
\r
1455 png_write_complete_chunk(png_ptr, png_bKGD, buf, 6);
\r
1460 if (back->gray >= (1 << png_ptr->bit_depth))
\r
1462 png_warning(png_ptr,
\r
1463 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
\r
1468 png_save_uint_16(buf, back->gray);
\r
1469 png_write_complete_chunk(png_ptr, png_bKGD, buf, 2);
\r
1474 #ifdef PNG_WRITE_eXIf_SUPPORTED
\r
1475 /* Write the Exif data */
\r
1476 void /* PRIVATE */
\r
1477 png_write_eXIf(png_structrp png_ptr, png_bytep exif, int num_exif)
\r
1482 png_debug(1, "in png_write_eXIf");
\r
1484 png_write_chunk_header(png_ptr, png_eXIf, (png_uint_32)(num_exif));
\r
1486 for (i = 0; i < num_exif; i++)
\r
1489 png_write_chunk_data(png_ptr, buf, 1);
\r
1492 png_write_chunk_end(png_ptr);
\r
1496 #ifdef PNG_WRITE_hIST_SUPPORTED
\r
1497 /* Write the histogram */
\r
1498 void /* PRIVATE */
\r
1499 png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
\r
1504 png_debug(1, "in png_write_hIST");
\r
1506 if (num_hist > (int)png_ptr->num_palette)
\r
1508 png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
\r
1509 png_ptr->num_palette);
\r
1511 png_warning(png_ptr, "Invalid number of histogram entries specified");
\r
1515 png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
\r
1517 for (i = 0; i < num_hist; i++)
\r
1519 png_save_uint_16(buf, hist[i]);
\r
1520 png_write_chunk_data(png_ptr, buf, 2);
\r
1523 png_write_chunk_end(png_ptr);
\r
1527 #ifdef PNG_WRITE_tEXt_SUPPORTED
\r
1528 /* Write a tEXt chunk */
\r
1529 void /* PRIVATE */
\r
1530 png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
\r
1533 png_uint_32 key_len;
\r
1534 png_byte new_key[80];
\r
1536 png_debug(1, "in png_write_tEXt");
\r
1538 key_len = png_check_keyword(png_ptr, key, new_key);
\r
1541 png_error(png_ptr, "tEXt: invalid keyword");
\r
1543 if (text == NULL || *text == '\0')
\r
1547 text_len = strlen(text);
\r
1549 if (text_len > PNG_UINT_31_MAX - (key_len+1))
\r
1550 png_error(png_ptr, "tEXt: text too long");
\r
1552 /* Make sure we include the 0 after the key */
\r
1553 png_write_chunk_header(png_ptr, png_tEXt,
\r
1554 (png_uint_32)/*checked above*/(key_len + text_len + 1));
\r
1556 * We leave it to the application to meet PNG-1.0 requirements on the
\r
1557 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
\r
1558 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
\r
1559 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
\r
1561 png_write_chunk_data(png_ptr, new_key, key_len + 1);
\r
1563 if (text_len != 0)
\r
1564 png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);
\r
1566 png_write_chunk_end(png_ptr);
\r
1570 #ifdef PNG_WRITE_zTXt_SUPPORTED
\r
1571 /* Write a compressed text chunk */
\r
1572 void /* PRIVATE */
\r
1573 png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
\r
1576 png_uint_32 key_len;
\r
1577 png_byte new_key[81];
\r
1578 compression_state comp;
\r
1580 png_debug(1, "in png_write_zTXt");
\r
1582 if (compression == PNG_TEXT_COMPRESSION_NONE)
\r
1584 png_write_tEXt(png_ptr, key, text, 0);
\r
1588 if (compression != PNG_TEXT_COMPRESSION_zTXt)
\r
1589 png_error(png_ptr, "zTXt: invalid compression type");
\r
1591 key_len = png_check_keyword(png_ptr, key, new_key);
\r
1594 png_error(png_ptr, "zTXt: invalid keyword");
\r
1596 /* Add the compression method and 1 for the keyword separator. */
\r
1597 new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
\r
1600 /* Compute the compressed data; do it now for the length */
\r
1601 png_text_compress_init(&comp, (png_const_bytep)text,
\r
1602 text == NULL ? 0 : strlen(text));
\r
1604 if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK)
\r
1605 png_error(png_ptr, png_ptr->zstream.msg);
\r
1607 /* Write start of chunk */
\r
1608 png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len);
\r
1611 png_write_chunk_data(png_ptr, new_key, key_len);
\r
1613 /* Write the compressed data */
\r
1614 png_write_compressed_data_out(png_ptr, &comp);
\r
1616 /* Close the chunk */
\r
1617 png_write_chunk_end(png_ptr);
\r
1621 #ifdef PNG_WRITE_iTXt_SUPPORTED
\r
1622 /* Write an iTXt chunk */
\r
1623 void /* PRIVATE */
\r
1624 png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
\r
1625 png_const_charp lang, png_const_charp lang_key, png_const_charp text)
\r
1627 png_uint_32 key_len, prefix_len;
\r
1628 size_t lang_len, lang_key_len;
\r
1629 png_byte new_key[82];
\r
1630 compression_state comp;
\r
1632 png_debug(1, "in png_write_iTXt");
\r
1634 key_len = png_check_keyword(png_ptr, key, new_key);
\r
1637 png_error(png_ptr, "iTXt: invalid keyword");
\r
1639 /* Set the compression flag */
\r
1640 switch (compression)
\r
1642 case PNG_ITXT_COMPRESSION_NONE:
\r
1643 case PNG_TEXT_COMPRESSION_NONE:
\r
1644 compression = new_key[++key_len] = 0; /* no compression */
\r
1647 case PNG_TEXT_COMPRESSION_zTXt:
\r
1648 case PNG_ITXT_COMPRESSION_zTXt:
\r
1649 compression = new_key[++key_len] = 1; /* compressed */
\r
1653 png_error(png_ptr, "iTXt: invalid compression");
\r
1656 new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
\r
1657 ++key_len; /* for the keywod separator */
\r
1659 /* We leave it to the application to meet PNG-1.0 requirements on the
\r
1660 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
\r
1661 * any non-Latin-1 characters except for NEWLINE. ISO PNG, however,
\r
1662 * specifies that the text is UTF-8 and this really doesn't require any
\r
1665 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
\r
1667 * TODO: validate the language tag correctly (see the spec.)
\r
1669 if (lang == NULL) lang = ""; /* empty language is valid */
\r
1670 lang_len = strlen(lang)+1;
\r
1671 if (lang_key == NULL) lang_key = ""; /* may be empty */
\r
1672 lang_key_len = strlen(lang_key)+1;
\r
1673 if (text == NULL) text = ""; /* may be empty */
\r
1675 prefix_len = key_len;
\r
1676 if (lang_len > PNG_UINT_31_MAX-prefix_len)
\r
1677 prefix_len = PNG_UINT_31_MAX;
\r
1679 prefix_len = (png_uint_32)(prefix_len + lang_len);
\r
1681 if (lang_key_len > PNG_UINT_31_MAX-prefix_len)
\r
1682 prefix_len = PNG_UINT_31_MAX;
\r
1684 prefix_len = (png_uint_32)(prefix_len + lang_key_len);
\r
1686 png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));
\r
1688 if (compression != 0)
\r
1690 if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
\r
1691 png_error(png_ptr, png_ptr->zstream.msg);
\r
1696 if (comp.input_len > PNG_UINT_31_MAX-prefix_len)
\r
1697 png_error(png_ptr, "iTXt: uncompressed text too long");
\r
1699 /* So the string will fit in a chunk: */
\r
1700 comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;
\r
1703 png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);
\r
1705 png_write_chunk_data(png_ptr, new_key, key_len);
\r
1707 png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);
\r
1709 png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);
\r
1711 if (compression != 0)
\r
1712 png_write_compressed_data_out(png_ptr, &comp);
\r
1715 png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len);
\r
1717 png_write_chunk_end(png_ptr);
\r
1721 #ifdef PNG_WRITE_oFFs_SUPPORTED
\r
1722 /* Write the oFFs chunk */
\r
1723 void /* PRIVATE */
\r
1724 png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
\r
1729 png_debug(1, "in png_write_oFFs");
\r
1731 if (unit_type >= PNG_OFFSET_LAST)
\r
1732 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
\r
1734 png_save_int_32(buf, x_offset);
\r
1735 png_save_int_32(buf + 4, y_offset);
\r
1736 buf[8] = (png_byte)unit_type;
\r
1738 png_write_complete_chunk(png_ptr, png_oFFs, buf, 9);
\r
1741 #ifdef PNG_WRITE_pCAL_SUPPORTED
\r
1742 /* Write the pCAL chunk (described in the PNG extensions document) */
\r
1743 void /* PRIVATE */
\r
1744 png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
\r
1745 png_int_32 X1, int type, int nparams, png_const_charp units,
\r
1746 png_charpp params)
\r
1748 png_uint_32 purpose_len;
\r
1749 size_t units_len, total_len;
\r
1750 png_size_tp params_len;
\r
1752 png_byte new_purpose[80];
\r
1755 png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
\r
1757 if (type >= PNG_EQUATION_LAST)
\r
1758 png_error(png_ptr, "Unrecognized equation type for pCAL chunk");
\r
1760 purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);
\r
1762 if (purpose_len == 0)
\r
1763 png_error(png_ptr, "pCAL: invalid keyword");
\r
1765 ++purpose_len; /* terminator */
\r
1767 png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
\r
1768 units_len = strlen(units) + (nparams == 0 ? 0 : 1);
\r
1769 png_debug1(3, "pCAL units length = %d", (int)units_len);
\r
1770 total_len = purpose_len + units_len + 10;
\r
1772 params_len = (png_size_tp)png_malloc(png_ptr,
\r
1773 (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (size_t))));
\r
1775 /* Find the length of each parameter, making sure we don't count the
\r
1776 * null terminator for the last parameter.
\r
1778 for (i = 0; i < nparams; i++)
\r
1780 params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
\r
1781 png_debug2(3, "pCAL parameter %d length = %lu", i,
\r
1782 (unsigned long)params_len[i]);
\r
1783 total_len += params_len[i];
\r
1786 png_debug1(3, "pCAL total length = %d", (int)total_len);
\r
1787 png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
\r
1788 png_write_chunk_data(png_ptr, new_purpose, purpose_len);
\r
1789 png_save_int_32(buf, X0);
\r
1790 png_save_int_32(buf + 4, X1);
\r
1791 buf[8] = (png_byte)type;
\r
1792 buf[9] = (png_byte)nparams;
\r
1793 png_write_chunk_data(png_ptr, buf, 10);
\r
1794 png_write_chunk_data(png_ptr, (png_const_bytep)units, (size_t)units_len);
\r
1796 for (i = 0; i < nparams; i++)
\r
1798 png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
\r
1801 png_free(png_ptr, params_len);
\r
1802 png_write_chunk_end(png_ptr);
\r
1806 #ifdef PNG_WRITE_sCAL_SUPPORTED
\r
1807 /* Write the sCAL chunk */
\r
1808 void /* PRIVATE */
\r
1809 png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
\r
1810 png_const_charp height)
\r
1813 size_t wlen, hlen, total_len;
\r
1815 png_debug(1, "in png_write_sCAL_s");
\r
1817 wlen = strlen(width);
\r
1818 hlen = strlen(height);
\r
1819 total_len = wlen + hlen + 2;
\r
1821 if (total_len > 64)
\r
1823 png_warning(png_ptr, "Can't write sCAL (buffer too small)");
\r
1827 buf[0] = (png_byte)unit;
\r
1828 memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */
\r
1829 memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
\r
1831 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
\r
1832 png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
\r
1836 #ifdef PNG_WRITE_pHYs_SUPPORTED
\r
1837 /* Write the pHYs chunk */
\r
1838 void /* PRIVATE */
\r
1839 png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,
\r
1840 png_uint_32 y_pixels_per_unit,
\r
1845 png_debug(1, "in png_write_pHYs");
\r
1847 if (unit_type >= PNG_RESOLUTION_LAST)
\r
1848 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
\r
1850 png_save_uint_32(buf, x_pixels_per_unit);
\r
1851 png_save_uint_32(buf + 4, y_pixels_per_unit);
\r
1852 buf[8] = (png_byte)unit_type;
\r
1854 png_write_complete_chunk(png_ptr, png_pHYs, buf, 9);
\r
1858 #ifdef PNG_WRITE_tIME_SUPPORTED
\r
1859 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
\r
1860 * or png_convert_from_time_t(), or fill in the structure yourself.
\r
1862 void /* PRIVATE */
\r
1863 png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
\r
1867 png_debug(1, "in png_write_tIME");
\r
1869 if (mod_time->month > 12 || mod_time->month < 1 ||
\r
1870 mod_time->day > 31 || mod_time->day < 1 ||
\r
1871 mod_time->hour > 23 || mod_time->second > 60)
\r
1873 png_warning(png_ptr, "Invalid time specified for tIME chunk");
\r
1877 png_save_uint_16(buf, mod_time->year);
\r
1878 buf[2] = mod_time->month;
\r
1879 buf[3] = mod_time->day;
\r
1880 buf[4] = mod_time->hour;
\r
1881 buf[5] = mod_time->minute;
\r
1882 buf[6] = mod_time->second;
\r
1884 png_write_complete_chunk(png_ptr, png_tIME, buf, 7);
\r
1888 /* Initializes the row writing capability of libpng */
\r
1889 void /* PRIVATE */
\r
1890 png_write_start_row(png_structrp png_ptr)
\r
1892 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
1893 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
\r
1895 /* Start of interlace block */
\r
1896 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
\r
1898 /* Offset to next interlace block */
\r
1899 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
\r
1901 /* Start of interlace block in the y direction */
\r
1902 static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
\r
1904 /* Offset to next interlace block in the y direction */
\r
1905 static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
\r
1908 png_alloc_size_t buf_size;
\r
1909 int usr_pixel_depth;
\r
1911 #ifdef PNG_WRITE_FILTER_SUPPORTED
\r
1915 png_debug(1, "in png_write_start_row");
\r
1917 usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
\r
1918 buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
\r
1920 /* 1.5.6: added to allow checking in the row write code. */
\r
1921 png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
\r
1922 png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
\r
1924 /* Set up row buffer */
\r
1925 png_ptr->row_buf = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
\r
1927 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
\r
1929 #ifdef PNG_WRITE_FILTER_SUPPORTED
\r
1930 filters = png_ptr->do_filter;
\r
1932 if (png_ptr->height == 1)
\r
1933 filters &= 0xff & ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
\r
1935 if (png_ptr->width == 1)
\r
1936 filters &= 0xff & ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
\r
1939 filters = PNG_FILTER_NONE;
\r
1941 png_ptr->do_filter = filters;
\r
1943 if (((filters & (PNG_FILTER_SUB | PNG_FILTER_UP | PNG_FILTER_AVG |
\r
1944 PNG_FILTER_PAETH)) != 0) && png_ptr->try_row == NULL)
\r
1946 int num_filters = 0;
\r
1948 png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
\r
1950 if (filters & PNG_FILTER_SUB)
\r
1953 if (filters & PNG_FILTER_UP)
\r
1956 if (filters & PNG_FILTER_AVG)
\r
1959 if (filters & PNG_FILTER_PAETH)
\r
1962 if (num_filters > 1)
\r
1963 png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr,
\r
1967 /* We only need to keep the previous row if we are using one of the following
\r
1970 if ((filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
\r
1971 png_ptr->prev_row = png_voidcast(png_bytep,
\r
1972 png_calloc(png_ptr, buf_size));
\r
1973 #endif /* WRITE_FILTER */
\r
1975 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
1976 /* If interlaced, we need to set up width and height of pass */
\r
1977 if (png_ptr->interlaced != 0)
\r
1979 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
\r
1981 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
\r
1982 png_pass_ystart[0]) / png_pass_yinc[0];
\r
1984 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
\r
1985 png_pass_start[0]) / png_pass_inc[0];
\r
1990 png_ptr->num_rows = png_ptr->height;
\r
1991 png_ptr->usr_width = png_ptr->width;
\r
1998 png_ptr->num_rows = png_ptr->height;
\r
1999 png_ptr->usr_width = png_ptr->width;
\r
2003 /* Internal use only. Called when finished processing a row of data. */
\r
2004 void /* PRIVATE */
\r
2005 png_write_finish_row(png_structrp png_ptr)
\r
2007 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
2008 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
\r
2010 /* Start of interlace block */
\r
2011 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
\r
2013 /* Offset to next interlace block */
\r
2014 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
\r
2016 /* Start of interlace block in the y direction */
\r
2017 static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
\r
2019 /* Offset to next interlace block in the y direction */
\r
2020 static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
\r
2023 png_debug(1, "in png_write_finish_row");
\r
2026 png_ptr->row_number++;
\r
2028 /* See if we are done */
\r
2029 if (png_ptr->row_number < png_ptr->num_rows)
\r
2032 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
2033 /* If interlaced, go to next pass */
\r
2034 if (png_ptr->interlaced != 0)
\r
2036 png_ptr->row_number = 0;
\r
2037 if ((png_ptr->transformations & PNG_INTERLACE) != 0)
\r
2044 /* Loop until we find a non-zero width or height pass */
\r
2049 if (png_ptr->pass >= 7)
\r
2052 png_ptr->usr_width = (png_ptr->width +
\r
2053 png_pass_inc[png_ptr->pass] - 1 -
\r
2054 png_pass_start[png_ptr->pass]) /
\r
2055 png_pass_inc[png_ptr->pass];
\r
2057 png_ptr->num_rows = (png_ptr->height +
\r
2058 png_pass_yinc[png_ptr->pass] - 1 -
\r
2059 png_pass_ystart[png_ptr->pass]) /
\r
2060 png_pass_yinc[png_ptr->pass];
\r
2062 if ((png_ptr->transformations & PNG_INTERLACE) != 0)
\r
2065 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
\r
2069 /* Reset the row above the image for the next pass */
\r
2070 if (png_ptr->pass < 7)
\r
2072 if (png_ptr->prev_row != NULL)
\r
2073 memset(png_ptr->prev_row, 0,
\r
2074 PNG_ROWBYTES(png_ptr->usr_channels *
\r
2075 png_ptr->usr_bit_depth, png_ptr->width) + 1);
\r
2082 /* If we get here, we've just written the last row, so we need
\r
2083 to flush the compressor */
\r
2084 png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);
\r
2087 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
\r
2088 /* Pick out the correct pixels for the interlace pass.
\r
2089 * The basic idea here is to go through the row with a source
\r
2090 * pointer and a destination pointer (sp and dp), and copy the
\r
2091 * correct pixels for the pass. As the row gets compacted,
\r
2092 * sp will always be >= dp, so we should never overwrite anything.
\r
2093 * See the default: case for the easiest code to understand.
\r
2095 void /* PRIVATE */
\r
2096 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
\r
2098 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
\r
2100 /* Start of interlace block */
\r
2101 static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
\r
2103 /* Offset to next interlace block */
\r
2104 static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
\r
2106 png_debug(1, "in png_do_write_interlace");
\r
2108 /* We don't have to do anything on the last pass (6) */
\r
2111 /* Each pixel depth is handled separately */
\r
2112 switch (row_info->pixel_depth)
\r
2118 unsigned int shift;
\r
2122 png_uint_32 row_width = row_info->width;
\r
2128 for (i = png_pass_start[pass]; i < row_width;
\r
2129 i += png_pass_inc[pass])
\r
2131 sp = row + (size_t)(i >> 3);
\r
2132 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
\r
2133 d |= (value << shift);
\r
2138 *dp++ = (png_byte)d;
\r
2147 *dp = (png_byte)d;
\r
2156 unsigned int shift;
\r
2160 png_uint_32 row_width = row_info->width;
\r
2166 for (i = png_pass_start[pass]; i < row_width;
\r
2167 i += png_pass_inc[pass])
\r
2169 sp = row + (size_t)(i >> 2);
\r
2170 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
\r
2171 d |= (value << shift);
\r
2176 *dp++ = (png_byte)d;
\r
2184 *dp = (png_byte)d;
\r
2193 unsigned int shift;
\r
2197 png_uint_32 row_width = row_info->width;
\r
2202 for (i = png_pass_start[pass]; i < row_width;
\r
2203 i += png_pass_inc[pass])
\r
2205 sp = row + (size_t)(i >> 1);
\r
2206 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
\r
2207 d |= (value << shift);
\r
2212 *dp++ = (png_byte)d;
\r
2220 *dp = (png_byte)d;
\r
2230 png_uint_32 row_width = row_info->width;
\r
2231 size_t pixel_bytes;
\r
2233 /* Start at the beginning */
\r
2236 /* Find out how many bytes each pixel takes up */
\r
2237 pixel_bytes = (row_info->pixel_depth >> 3);
\r
2239 /* Loop through the row, only looking at the pixels that matter */
\r
2240 for (i = png_pass_start[pass]; i < row_width;
\r
2241 i += png_pass_inc[pass])
\r
2243 /* Find out where the original pixel is */
\r
2244 sp = row + (size_t)i * pixel_bytes;
\r
2246 /* Move the pixel */
\r
2248 memcpy(dp, sp, pixel_bytes);
\r
2251 dp += pixel_bytes;
\r
2256 /* Set new row width */
\r
2257 row_info->width = (row_info->width +
\r
2258 png_pass_inc[pass] - 1 -
\r
2259 png_pass_start[pass]) /
\r
2260 png_pass_inc[pass];
\r
2262 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
\r
2269 /* This filters the row, chooses which filter to use, if it has not already
\r
2270 * been specified by the application, and then writes the row out with the
\r
2273 static void /* PRIVATE */
\r
2274 png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
\r
2275 size_t row_bytes);
\r
2277 #ifdef PNG_WRITE_FILTER_SUPPORTED
\r
2278 static size_t /* PRIVATE */
\r
2279 png_setup_sub_row(png_structrp png_ptr, png_uint_32 bpp,
\r
2280 size_t row_bytes, size_t lmins)
\r
2282 png_bytep rp, dp, lp;
\r
2287 png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
\r
2289 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
\r
2293 #ifdef PNG_USE_ABS
\r
2294 sum += 128 - abs((int)v - 128);
\r
2296 sum += (v < 128) ? v : 256 - v;
\r
2300 for (lp = png_ptr->row_buf + 1; i < row_bytes;
\r
2301 i++, rp++, lp++, dp++)
\r
2303 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
\r
2304 #ifdef PNG_USE_ABS
\r
2305 sum += 128 - abs((int)v - 128);
\r
2307 sum += (v < 128) ? v : 256 - v;
\r
2310 if (sum > lmins) /* We are already worse, don't continue. */
\r
2317 static void /* PRIVATE */
\r
2318 png_setup_sub_row_only(png_structrp png_ptr, png_uint_32 bpp,
\r
2321 png_bytep rp, dp, lp;
\r
2324 png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
\r
2326 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
\r
2332 for (lp = png_ptr->row_buf + 1; i < row_bytes;
\r
2333 i++, rp++, lp++, dp++)
\r
2335 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
\r
2339 static size_t /* PRIVATE */
\r
2340 png_setup_up_row(png_structrp png_ptr, size_t row_bytes, size_t lmins)
\r
2342 png_bytep rp, dp, pp;
\r
2347 png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
\r
2349 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
\r
2350 pp = png_ptr->prev_row + 1; i < row_bytes;
\r
2351 i++, rp++, pp++, dp++)
\r
2353 v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
\r
2354 #ifdef PNG_USE_ABS
\r
2355 sum += 128 - abs((int)v - 128);
\r
2357 sum += (v < 128) ? v : 256 - v;
\r
2360 if (sum > lmins) /* We are already worse, don't continue. */
\r
2366 static void /* PRIVATE */
\r
2367 png_setup_up_row_only(png_structrp png_ptr, size_t row_bytes)
\r
2369 png_bytep rp, dp, pp;
\r
2372 png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
\r
2374 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
\r
2375 pp = png_ptr->prev_row + 1; i < row_bytes;
\r
2376 i++, rp++, pp++, dp++)
\r
2378 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
\r
2382 static size_t /* PRIVATE */
\r
2383 png_setup_avg_row(png_structrp png_ptr, png_uint_32 bpp,
\r
2384 size_t row_bytes, size_t lmins)
\r
2386 png_bytep rp, dp, pp, lp;
\r
2391 png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
\r
2393 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
\r
2394 pp = png_ptr->prev_row + 1; i < bpp; i++)
\r
2396 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
\r
2398 #ifdef PNG_USE_ABS
\r
2399 sum += 128 - abs((int)v - 128);
\r
2401 sum += (v < 128) ? v : 256 - v;
\r
2405 for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
\r
2407 v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
\r
2410 #ifdef PNG_USE_ABS
\r
2411 sum += 128 - abs((int)v - 128);
\r
2413 sum += (v < 128) ? v : 256 - v;
\r
2416 if (sum > lmins) /* We are already worse, don't continue. */
\r
2422 static void /* PRIVATE */
\r
2423 png_setup_avg_row_only(png_structrp png_ptr, png_uint_32 bpp,
\r
2426 png_bytep rp, dp, pp, lp;
\r
2429 png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
\r
2431 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
\r
2432 pp = png_ptr->prev_row + 1; i < bpp; i++)
\r
2434 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
\r
2437 for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
\r
2439 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
\r
2444 static size_t /* PRIVATE */
\r
2445 png_setup_paeth_row(png_structrp png_ptr, png_uint_32 bpp,
\r
2446 size_t row_bytes, size_t lmins)
\r
2448 png_bytep rp, dp, pp, cp, lp;
\r
2453 png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
\r
2455 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
\r
2456 pp = png_ptr->prev_row + 1; i < bpp; i++)
\r
2458 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
\r
2460 #ifdef PNG_USE_ABS
\r
2461 sum += 128 - abs((int)v - 128);
\r
2463 sum += (v < 128) ? v : 256 - v;
\r
2467 for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
\r
2470 int a, b, c, pa, pb, pc, p;
\r
2479 #ifdef PNG_USE_ABS
\r
2484 pa = p < 0 ? -p : p;
\r
2485 pb = pc < 0 ? -pc : pc;
\r
2486 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
\r
2489 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
\r
2491 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
\r
2493 #ifdef PNG_USE_ABS
\r
2494 sum += 128 - abs((int)v - 128);
\r
2496 sum += (v < 128) ? v : 256 - v;
\r
2499 if (sum > lmins) /* We are already worse, don't continue. */
\r
2505 static void /* PRIVATE */
\r
2506 png_setup_paeth_row_only(png_structrp png_ptr, png_uint_32 bpp,
\r
2509 png_bytep rp, dp, pp, cp, lp;
\r
2512 png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
\r
2514 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
\r
2515 pp = png_ptr->prev_row + 1; i < bpp; i++)
\r
2517 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
\r
2520 for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
\r
2523 int a, b, c, pa, pb, pc, p;
\r
2532 #ifdef PNG_USE_ABS
\r
2537 pa = p < 0 ? -p : p;
\r
2538 pb = pc < 0 ? -pc : pc;
\r
2539 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
\r
2542 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
\r
2544 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
\r
2547 #endif /* WRITE_FILTER */
\r
2549 void /* PRIVATE */
\r
2550 png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
\r
2552 #ifndef PNG_WRITE_FILTER_SUPPORTED
\r
2553 png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
\r
2555 unsigned int filter_to_do = png_ptr->do_filter;
\r
2556 png_bytep row_buf;
\r
2557 png_bytep best_row;
\r
2560 size_t row_bytes = row_info->rowbytes;
\r
2562 png_debug(1, "in png_write_find_filter");
\r
2564 /* Find out how many bytes offset each pixel is */
\r
2565 bpp = (row_info->pixel_depth + 7) >> 3;
\r
2567 row_buf = png_ptr->row_buf;
\r
2568 mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the
\r
2571 /* The prediction method we use is to find which method provides the
\r
2572 * smallest value when summing the absolute values of the distances
\r
2573 * from zero, using anything >= 128 as negative numbers. This is known
\r
2574 * as the "minimum sum of absolute differences" heuristic. Other
\r
2575 * heuristics are the "weighted minimum sum of absolute differences"
\r
2576 * (experimental and can in theory improve compression), and the "zlib
\r
2577 * predictive" method (not implemented yet), which does test compressions
\r
2578 * of lines using different filter methods, and then chooses the
\r
2579 * (series of) filter(s) that give minimum compressed data size (VERY
\r
2580 * computationally expensive).
\r
2582 * GRR 980525: consider also
\r
2584 * (1) minimum sum of absolute differences from running average (i.e.,
\r
2585 * keep running sum of non-absolute differences & count of bytes)
\r
2586 * [track dispersion, too? restart average if dispersion too large?]
\r
2588 * (1b) minimum sum of absolute differences from sliding average, probably
\r
2589 * with window size <= deflate window (usually 32K)
\r
2591 * (2) minimum sum of squared differences from zero or running average
\r
2592 * (i.e., ~ root-mean-square approach)
\r
2596 /* We don't need to test the 'no filter' case if this is the only filter
\r
2597 * that has been chosen, as it doesn't actually do anything to the data.
\r
2599 best_row = png_ptr->row_buf;
\r
2601 if (PNG_SIZE_MAX/128 <= row_bytes)
\r
2603 /* Overflow can occur in the calculation, just select the lowest set
\r
2606 filter_to_do &= 0U-filter_to_do;
\r
2608 else if ((filter_to_do & PNG_FILTER_NONE) != 0 &&
\r
2609 filter_to_do != PNG_FILTER_NONE)
\r
2611 /* Overflow not possible and multiple filters in the list, including the
\r
2620 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
\r
2623 #ifdef PNG_USE_ABS
\r
2624 sum += 128 - abs((int)v - 128);
\r
2626 sum += (v < 128) ? v : 256 - v;
\r
2635 if (filter_to_do == PNG_FILTER_SUB)
\r
2636 /* It's the only filter so no testing is needed */
\r
2638 png_setup_sub_row_only(png_ptr, bpp, row_bytes);
\r
2639 best_row = png_ptr->try_row;
\r
2642 else if ((filter_to_do & PNG_FILTER_SUB) != 0)
\r
2645 size_t lmins = mins;
\r
2647 sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins);
\r
2652 best_row = png_ptr->try_row;
\r
2653 if (png_ptr->tst_row != NULL)
\r
2655 png_ptr->try_row = png_ptr->tst_row;
\r
2656 png_ptr->tst_row = best_row;
\r
2662 if (filter_to_do == PNG_FILTER_UP)
\r
2664 png_setup_up_row_only(png_ptr, row_bytes);
\r
2665 best_row = png_ptr->try_row;
\r
2668 else if ((filter_to_do & PNG_FILTER_UP) != 0)
\r
2671 size_t lmins = mins;
\r
2673 sum = png_setup_up_row(png_ptr, row_bytes, lmins);
\r
2678 best_row = png_ptr->try_row;
\r
2679 if (png_ptr->tst_row != NULL)
\r
2681 png_ptr->try_row = png_ptr->tst_row;
\r
2682 png_ptr->tst_row = best_row;
\r
2688 if (filter_to_do == PNG_FILTER_AVG)
\r
2690 png_setup_avg_row_only(png_ptr, bpp, row_bytes);
\r
2691 best_row = png_ptr->try_row;
\r
2694 else if ((filter_to_do & PNG_FILTER_AVG) != 0)
\r
2697 size_t lmins = mins;
\r
2699 sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins);
\r
2704 best_row = png_ptr->try_row;
\r
2705 if (png_ptr->tst_row != NULL)
\r
2707 png_ptr->try_row = png_ptr->tst_row;
\r
2708 png_ptr->tst_row = best_row;
\r
2713 /* Paeth filter */
\r
2714 if (filter_to_do == PNG_FILTER_PAETH)
\r
2716 png_setup_paeth_row_only(png_ptr, bpp, row_bytes);
\r
2717 best_row = png_ptr->try_row;
\r
2720 else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
\r
2723 size_t lmins = mins;
\r
2725 sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
\r
2729 best_row = png_ptr->try_row;
\r
2730 if (png_ptr->tst_row != NULL)
\r
2732 png_ptr->try_row = png_ptr->tst_row;
\r
2733 png_ptr->tst_row = best_row;
\r
2738 /* Do the actual writing of the filtered row data from the chosen filter. */
\r
2739 png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
\r
2741 #endif /* WRITE_FILTER */
\r
2745 /* Do the actual writing of a previously filtered row. */
\r
2747 png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
\r
2748 size_t full_row_length/*includes filter byte*/)
\r
2750 png_debug(1, "in png_write_filtered_row");
\r
2752 png_debug1(2, "filter = %d", filtered_row[0]);
\r
2754 png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
\r
2756 #ifdef PNG_WRITE_FILTER_SUPPORTED
\r
2757 /* Swap the current and previous rows */
\r
2758 if (png_ptr->prev_row != NULL)
\r
2762 tptr = png_ptr->prev_row;
\r
2763 png_ptr->prev_row = png_ptr->row_buf;
\r
2764 png_ptr->row_buf = tptr;
\r
2766 #endif /* WRITE_FILTER */
\r
2768 /* Finish row - updates counters and flushes zlib if last row */
\r
2769 png_write_finish_row(png_ptr);
\r
2771 #ifdef PNG_WRITE_FLUSH_SUPPORTED
\r
2772 png_ptr->flush_rows++;
\r
2774 if (png_ptr->flush_dist > 0 &&
\r
2775 png_ptr->flush_rows >= png_ptr->flush_dist)
\r
2777 png_write_flush(png_ptr);
\r
2779 #endif /* WRITE_FLUSH */
\r
2781 #endif /* WRITE */
\r