Mercurial > mm7
view lib/libpng/pngwutil.c @ 2458:d53da932f594
include legacy_dx libs
| author | Ritor1 |
|---|---|
| date | Sat, 26 Jul 2014 13:03:43 +0600 |
| parents | 6e178010fc29 |
| children |
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/* pngwutil.c - utilities to write a PNG file * * Last changed in libpng 1.6.2 [April 25, 2013] * Copyright (c) 1998-2013 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h */ #include "pngpriv.h" #ifdef PNG_WRITE_SUPPORTED #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED /* Place a 32-bit number into a buffer in PNG byte order. We work * with unsigned numbers for convenience, although one supported * ancillary chunk uses signed (two's complement) numbers. */ void PNGAPI png_save_uint_32(png_bytep buf, png_uint_32 i) { buf[0] = (png_byte)((i >> 24) & 0xff); buf[1] = (png_byte)((i >> 16) & 0xff); buf[2] = (png_byte)((i >> 8) & 0xff); buf[3] = (png_byte)(i & 0xff); } /* Place a 16-bit number into a buffer in PNG byte order. * The parameter is declared unsigned int, not png_uint_16, * just to avoid potential problems on pre-ANSI C compilers. */ void PNGAPI png_save_uint_16(png_bytep buf, unsigned int i) { buf[0] = (png_byte)((i >> 8) & 0xff); buf[1] = (png_byte)(i & 0xff); } #endif /* Simple function to write the signature. If we have already written * the magic bytes of the signature, or more likely, the PNG stream is * being embedded into another stream and doesn't need its own signature, * we should call png_set_sig_bytes() to tell libpng how many of the * bytes have already been written. */ void PNGAPI png_write_sig(png_structrp png_ptr) { png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; #ifdef PNG_IO_STATE_SUPPORTED /* Inform the I/O callback that the signature is being written */ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE; #endif /* Write the rest of the 8 byte signature */ png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes], (png_size_t)(8 - png_ptr->sig_bytes)); if (png_ptr->sig_bytes < 3) png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; } /* Write the start of a PNG chunk. The type is the chunk type. * The total_length is the sum of the lengths of all the data you will be * passing in png_write_chunk_data(). */ static void png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name, png_uint_32 length) { png_byte buf[8]; #if defined(PNG_DEBUG) && (PNG_DEBUG > 0) PNG_CSTRING_FROM_CHUNK(buf, chunk_name); png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length); #endif if (png_ptr == NULL) return; #ifdef PNG_IO_STATE_SUPPORTED /* Inform the I/O callback that the chunk header is being written. * PNG_IO_CHUNK_HDR requires a single I/O call. */ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR; #endif /* Write the length and the chunk name */ png_save_uint_32(buf, length); png_save_uint_32(buf + 4, chunk_name); png_write_data(png_ptr, buf, 8); /* Put the chunk name into png_ptr->chunk_name */ png_ptr->chunk_name = chunk_name; /* Reset the crc and run it over the chunk name */ png_reset_crc(png_ptr); png_calculate_crc(png_ptr, buf + 4, 4); #ifdef PNG_IO_STATE_SUPPORTED /* Inform the I/O callback that chunk data will (possibly) be written. * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls. */ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA; #endif } void PNGAPI png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string, png_uint_32 length) { png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length); } /* Write the data of a PNG chunk started with png_write_chunk_header(). * Note that multiple calls to this function are allowed, and that the * sum of the lengths from these calls *must* add up to the total_length * given to png_write_chunk_header(). */ void PNGAPI png_write_chunk_data(png_structrp png_ptr, png_const_bytep data, png_size_t length) { /* Write the data, and run the CRC over it */ if (png_ptr == NULL) return; if (data != NULL && length > 0) { png_write_data(png_ptr, data, length); /* Update the CRC after writing the data, * in case that the user I/O routine alters it. */ png_calculate_crc(png_ptr, data, length); } } /* Finish a chunk started with png_write_chunk_header(). */ void PNGAPI png_write_chunk_end(png_structrp png_ptr) { png_byte buf[4]; if (png_ptr == NULL) return; #ifdef PNG_IO_STATE_SUPPORTED /* Inform the I/O callback that the chunk CRC is being written. * PNG_IO_CHUNK_CRC requires a single I/O function call. */ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC; #endif /* Write the crc in a single operation */ png_save_uint_32(buf, png_ptr->crc); png_write_data(png_ptr, buf, (png_size_t)4); } /* Write a PNG chunk all at once. The type is an array of ASCII characters * representing the chunk name. The array must be at least 4 bytes in * length, and does not need to be null terminated. To be safe, pass the * pre-defined chunk names here, and if you need a new one, define it * where the others are defined. The length is the length of the data. * All the data must be present. If that is not possible, use the * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end() * functions instead. */ static void png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name, png_const_bytep data, png_size_t length) { if (png_ptr == NULL) return; /* On 64 bit architectures 'length' may not fit in a png_uint_32. */ if (length > PNG_UINT_31_MAX) png_error(png_ptr, "length exceeds PNG maxima"); png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length); png_write_chunk_data(png_ptr, data, length); png_write_chunk_end(png_ptr); } /* This is the API that calls the internal function above. */ void PNGAPI png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string, png_const_bytep data, png_size_t length) { png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data, length); } /* This is used below to find the size of an image to pass to png_deflate_claim, * so it only needs to be accurate if the size is less than 16384 bytes (the * point at which a lower LZ window size can be used.) */ static png_alloc_size_t png_image_size(png_structrp png_ptr) { /* Only return sizes up to the maximum of a png_uint_32, do this by limiting * the width and height used to 15 bits. */ png_uint_32 h = png_ptr->height; if (png_ptr->rowbytes < 32768 && h < 32768) { if (png_ptr->interlaced) { /* Interlacing makes the image larger because of the replication of * both the filter byte and the padding to a byte boundary. */ png_uint_32 w = png_ptr->width; unsigned int pd = png_ptr->pixel_depth; png_alloc_size_t cb_base; int pass; for (cb_base=0, pass=0; pass<=6; ++pass) { png_uint_32 pw = PNG_PASS_COLS(w, pass); if (pw > 0) cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass); } return cb_base; } else return (png_ptr->rowbytes+1) * h; } else return 0xffffffffU; } #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED /* This is the code to hack the first two bytes of the deflate stream (the * deflate header) to correct the windowBits value to match the actual data * size. Note that the second argument is the *uncompressed* size but the * first argument is the *compressed* data (and it must be deflate * compressed.) */ static void optimize_cmf(png_bytep data, png_alloc_size_t data_size) { /* Optimize the CMF field in the zlib stream. The resultant zlib stream is * still compliant to the stream specification. */ if (data_size <= 16384) /* else windowBits must be 15 */ { unsigned int z_cmf = data[0]; /* zlib compression method and flags */ if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70) { unsigned int z_cinfo; unsigned int half_z_window_size; z_cinfo = z_cmf >> 4; half_z_window_size = 1U << (z_cinfo + 7); if (data_size <= half_z_window_size) /* else no change */ { unsigned int tmp; do { half_z_window_size >>= 1; --z_cinfo; } while (z_cinfo > 0 && data_size <= half_z_window_size); z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4); data[0] = (png_byte)z_cmf; tmp = data[1] & 0xe0; tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f; data[1] = (png_byte)tmp; } } } } #else # define optimize_cmf(dp,dl) ((void)0) #endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */ /* Initialize the compressor for the appropriate type of compression. */ static int png_deflate_claim(png_structrp png_ptr, png_uint_32 owner, png_alloc_size_t data_size) { if (png_ptr->zowner != 0) { char msg[64]; PNG_STRING_FROM_CHUNK(msg, owner); msg[4] = ':'; msg[5] = ' '; PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner); /* So the message that results is "<chunk> using zstream"; this is an * internal error, but is very useful for debugging. i18n requirements * are minimal. */ (void)png_safecat(msg, (sizeof msg), 10, " using zstream"); # if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC png_warning(png_ptr, msg); /* Attempt sane error recovery */ if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */ { png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT"); return Z_STREAM_ERROR; } png_ptr->zowner = 0; # else png_error(png_ptr, msg); # endif } { int level = png_ptr->zlib_level; int method = png_ptr->zlib_method; int windowBits = png_ptr->zlib_window_bits; int memLevel = png_ptr->zlib_mem_level; int strategy; /* set below */ int ret; /* zlib return code */ if (owner == png_IDAT) { if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) strategy = png_ptr->zlib_strategy; else if (png_ptr->do_filter != PNG_FILTER_NONE) strategy = PNG_Z_DEFAULT_STRATEGY; else strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY; } else { # ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED level = png_ptr->zlib_text_level; method = png_ptr->zlib_text_method; windowBits = png_ptr->zlib_text_window_bits; memLevel = png_ptr->zlib_text_mem_level; strategy = png_ptr->zlib_text_strategy; # else /* If customization is not supported the values all come from the * IDAT values except for the strategy, which is fixed to the * default. (This is the pre-1.6.0 behavior too, although it was * implemented in a very different way.) */ strategy = Z_DEFAULT_STRATEGY; # endif } /* Adjust 'windowBits' down if larger than 'data_size'; to stop this * happening just pass 32768 as the data_size parameter. Notice that zlib * requires an extra 262 bytes in the window in addition to the data to be * able to see the whole of the data, so if data_size+262 takes us to the * next windowBits size we need to fix up the value later. (Because even * though deflate needs the extra window, inflate does not!) */ if (data_size <= 16384) { /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to * work round a Microsoft Visual C misbehavior which, contrary to C-90, * widens the result of the following shift to 64-bits if (and, * apparently, only if) it is used in a test. */ unsigned int half_window_size = 1U << (windowBits-1); while (data_size + 262 <= half_window_size) { half_window_size >>= 1; --windowBits; } } /* Check against the previous initialized values, if any. */ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) && (png_ptr->zlib_set_level != level || png_ptr->zlib_set_method != method || png_ptr->zlib_set_window_bits != windowBits || png_ptr->zlib_set_mem_level != memLevel || png_ptr->zlib_set_strategy != strategy)) { if (deflateEnd(&png_ptr->zstream) != Z_OK) png_warning(png_ptr, "deflateEnd failed (ignored)"); png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED; } /* For safety clear out the input and output pointers (currently zlib * doesn't use them on Init, but it might in the future). */ png_ptr->zstream.next_in = NULL; png_ptr->zstream.avail_in = 0; png_ptr->zstream.next_out = NULL; png_ptr->zstream.avail_out = 0; /* Now initialize if required, setting the new parameters, otherwise just * to a simple reset to the previous parameters. */ if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) ret = deflateReset(&png_ptr->zstream); else { ret = deflateInit2(&png_ptr->zstream, level, method, windowBits, memLevel, strategy); if (ret == Z_OK) png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; } /* The return code is from either deflateReset or deflateInit2; they have * pretty much the same set of error codes. */ if (ret == Z_OK) png_ptr->zowner = owner; else png_zstream_error(png_ptr, ret); return ret; } } /* Clean up (or trim) a linked list of compression buffers. */ void /* PRIVATE */ png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp) { png_compression_bufferp list = *listp; if (list != NULL) { *listp = NULL; do { png_compression_bufferp next = list->next; png_free(png_ptr, list); list = next; } while (list != NULL); } } #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED /* This pair of functions encapsulates the operation of (a) compressing a * text string, and (b) issuing it later as a series of chunk data writes. * The compression_state structure is shared context for these functions * set up by the caller to allow access to the relevant local variables. * * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size * temporary buffers. From 1.6.0 it is retained in png_struct so that it will * be correctly freed in the event of a write error (previous implementations * just leaked memory.) */ typedef struct { png_const_bytep input; /* The uncompressed input data */ png_alloc_size_t input_len; /* Its length */ png_uint_32 output_len; /* Final compressed length */ png_byte output[1024]; /* First block of output */ } compression_state; static void png_text_compress_init(compression_state *comp, png_const_bytep input, png_alloc_size_t input_len) { comp->input = input; comp->input_len = input_len; comp->output_len = 0; } /* Compress the data in the compression state input */ static int png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name, compression_state *comp, png_uint_32 prefix_len) { int ret; /* To find the length of the output it is necessary to first compress the * input, the result is buffered rather than using the two-pass algorithm * that is used on the inflate side; deflate is assumed to be slower and a * PNG writer is assumed to have more memory available than a PNG reader. * * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an * upper limit on the output size, but it is always bigger than the input * size so it is likely to be more efficient to use this linked-list * approach. */ ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len); if (ret != Z_OK) return ret; /* Set up the compression buffers, we need a loop here to avoid overflowing a * uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited * by the output buffer size, so there is no need to check that. Since this * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits * in size. */ { png_compression_bufferp *end = &png_ptr->zbuffer_list; png_alloc_size_t input_len = comp->input_len; /* may be zero! */ png_uint_32 output_len; /* zlib updates these for us: */ png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input); png_ptr->zstream.avail_in = 0; /* Set below */ png_ptr->zstream.next_out = comp->output; png_ptr->zstream.avail_out = (sizeof comp->output); output_len = png_ptr->zstream.avail_out; do { uInt avail_in = ZLIB_IO_MAX; if (avail_in > input_len) avail_in = (uInt)input_len; input_len -= avail_in; png_ptr->zstream.avail_in = avail_in; if (png_ptr->zstream.avail_out == 0) { png_compression_buffer *next; /* Chunk data is limited to 2^31 bytes in length, so the prefix * length must be counted here. */ if (output_len + prefix_len > PNG_UINT_31_MAX) { ret = Z_MEM_ERROR; break; } /* Need a new (malloc'ed) buffer, but there may be one present * already. */ next = *end; if (next == NULL) { next = png_voidcast(png_compression_bufferp, png_malloc_base (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr))); if (next == NULL) { ret = Z_MEM_ERROR; break; } /* Link in this buffer (so that it will be freed later) */ next->next = NULL; *end = next; } png_ptr->zstream.next_out = next->output; png_ptr->zstream.avail_out = png_ptr->zbuffer_size; output_len += png_ptr->zstream.avail_out; /* Move 'end' to the next buffer pointer. */ end = &next->next; } /* Compress the data */ ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : Z_FINISH); /* Claw back input data that was not consumed (because avail_in is * reset above every time round the loop). */ input_len += png_ptr->zstream.avail_in; png_ptr->zstream.avail_in = 0; /* safety */ } while (ret == Z_OK); /* There may be some space left in the last output buffer, this needs to * be subtracted from output_len. */ output_len -= png_ptr->zstream.avail_out; png_ptr->zstream.avail_out = 0; /* safety */ comp->output_len = output_len; /* Now double check the output length, put in a custom message if it is * too long. Otherwise ensure the z_stream::msg pointer is set to * something. */ if (output_len + prefix_len >= PNG_UINT_31_MAX) { png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long"); ret = Z_MEM_ERROR; } else png_zstream_error(png_ptr, ret); /* Reset zlib for another zTXt/iTXt or image data */ png_ptr->zowner = 0; /* The only success case is Z_STREAM_END, input_len must be 0, if not this * is an internal error. */ if (ret == Z_STREAM_END && input_len == 0) { /* Fix up the deflate header, if required */ optimize_cmf(comp->output, comp->input_len); /* But Z_OK is returned, not Z_STREAM_END; this allows the claim * function above to return Z_STREAM_END on an error (though it never * does in the current versions of zlib.) */ return Z_OK; } else return ret; } } /* Ship the compressed text out via chunk writes */ static void png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp) { png_uint_32 output_len = comp->output_len; png_const_bytep output = comp->output; png_uint_32 avail = (sizeof comp->output); png_compression_buffer *next = png_ptr->zbuffer_list; for (;;) { if (avail > output_len) avail = output_len; png_write_chunk_data(png_ptr, output, avail); output_len -= avail; if (output_len == 0 || next == NULL) break; avail = png_ptr->zbuffer_size; output = next->output; next = next->next; } /* This is an internal error; 'next' must have been NULL! */ if (output_len > 0) png_error(png_ptr, "error writing ancillary chunked compressed data"); } #endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */ #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \ defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED) /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification, * and if invalid, correct the keyword rather than discarding the entire * chunk. The PNG 1.0 specification requires keywords 1-79 characters in * length, forbids leading or trailing whitespace, multiple internal spaces, * and the non-break space (0x80) from ISO 8859-1. Returns keyword length. * * The 'new_key' buffer must be 80 characters in size (for the keyword plus a * trailing '\0'). If this routine returns 0 then there was no keyword, or a * valid one could not be generated, and the caller must png_error. */ static png_uint_32 png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key) { png_const_charp orig_key = key; png_uint_32 key_len = 0; int bad_character = 0; int space = 1; png_debug(1, "in png_check_keyword"); if (key == NULL) { *new_key = 0; return 0; } while (*key && key_len < 79) { png_byte ch = (png_byte)(0xff & *key++); if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/)) *new_key++ = ch, ++key_len, space = 0; else if (!space) { /* A space or an invalid character when one wasn't seen immediately * before; output just a space. */ *new_key++ = 32, ++key_len, space = 1; /* If the character was not a space then it is invalid. */ if (ch != 32) bad_character = ch; } else if (!bad_character) bad_character = ch; /* just skip it, record the first error */ } if (key_len > 0 && space) /* trailing space */ { --key_len, --new_key; if (!bad_character) bad_character = 32; } /* Terminate the keyword */ *new_key = 0; if (key_len == 0) return 0; /* Try to only output one warning per keyword: */ if (*key) /* keyword too long */ png_warning(png_ptr, "keyword truncated"); else if (bad_character) { PNG_WARNING_PARAMETERS(p) png_warning_parameter(p, 1, orig_key); png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character); png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'"); } return key_len; } #endif /* Write the IHDR chunk, and update the png_struct with the necessary * information. Note that the rest of this code depends upon this * information being correct. */ void /* PRIVATE */ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height, int bit_depth, int color_type, int compression_type, int filter_type, int interlace_type) { png_byte buf[13]; /* Buffer to store the IHDR info */ png_debug(1, "in png_write_IHDR"); /* Check that we have valid input data from the application info */ switch (color_type) { case PNG_COLOR_TYPE_GRAY: switch (bit_depth) { case 1: case 2: case 4: case 8: #ifdef PNG_WRITE_16BIT_SUPPORTED case 16: #endif png_ptr->channels = 1; break; default: png_error(png_ptr, "Invalid bit depth for grayscale image"); } break; case PNG_COLOR_TYPE_RGB: #ifdef PNG_WRITE_16BIT_SUPPORTED if (bit_depth != 8 && bit_depth != 16) #else if (bit_depth != 8) #endif png_error(png_ptr, "Invalid bit depth for RGB image"); png_ptr->channels = 3; break; case PNG_COLOR_TYPE_PALETTE: switch (bit_depth) { case 1: case 2: case 4: case 8: png_ptr->channels = 1; break; default: png_error(png_ptr, "Invalid bit depth for paletted image"); } break; case PNG_COLOR_TYPE_GRAY_ALPHA: if (bit_depth != 8 && bit_depth != 16) png_error(png_ptr, "Invalid bit depth for grayscale+alpha image"); png_ptr->channels = 2; break; case PNG_COLOR_TYPE_RGB_ALPHA: #ifdef PNG_WRITE_16BIT_SUPPORTED if (bit_depth != 8 && bit_depth != 16) #else if (bit_depth != 8) #endif png_error(png_ptr, "Invalid bit depth for RGBA image"); png_ptr->channels = 4; break; default: png_error(png_ptr, "Invalid image color type specified"); } if (compression_type != PNG_COMPRESSION_TYPE_BASE) { png_warning(png_ptr, "Invalid compression type specified"); compression_type = PNG_COMPRESSION_TYPE_BASE; } /* Write filter_method 64 (intrapixel differencing) only if * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and * 2. Libpng did not write a PNG signature (this filter_method is only * used in PNG datastreams that are embedded in MNG datastreams) and * 3. The application called png_permit_mng_features with a mask that * included PNG_FLAG_MNG_FILTER_64 and * 4. The filter_method is 64 and * 5. The color_type is RGB or RGBA */ if ( #ifdef PNG_MNG_FEATURES_SUPPORTED !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) && (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_RGB_ALPHA) && (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) && #endif filter_type != PNG_FILTER_TYPE_BASE) { png_warning(png_ptr, "Invalid filter type specified"); filter_type = PNG_FILTER_TYPE_BASE; } #ifdef PNG_WRITE_INTERLACING_SUPPORTED if (interlace_type != PNG_INTERLACE_NONE && interlace_type != PNG_INTERLACE_ADAM7) { png_warning(png_ptr, "Invalid interlace type specified"); interlace_type = PNG_INTERLACE_ADAM7; } #else interlace_type=PNG_INTERLACE_NONE; #endif /* Save the relevent information */ png_ptr->bit_depth = (png_byte)bit_depth; png_ptr->color_type = (png_byte)color_type; png_ptr->interlaced = (png_byte)interlace_type; #ifdef PNG_MNG_FEATURES_SUPPORTED png_ptr->filter_type = (png_byte)filter_type; #endif png_ptr->compression_type = (png_byte)compression_type; png_ptr->width = width; png_ptr->height = height; png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels); png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width); /* Set the usr info, so any transformations can modify it */ png_ptr->usr_width = png_ptr->width; png_ptr->usr_bit_depth = png_ptr->bit_depth; png_ptr->usr_channels = png_ptr->channels; /* Pack the header information into the buffer */ png_save_uint_32(buf, width); png_save_uint_32(buf + 4, height); buf[8] = (png_byte)bit_depth; buf[9] = (png_byte)color_type; buf[10] = (png_byte)compression_type; buf[11] = (png_byte)filter_type; buf[12] = (png_byte)interlace_type; /* Write the chunk */ png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13); if (!(png_ptr->do_filter)) { if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE || png_ptr->bit_depth < 8) png_ptr->do_filter = PNG_FILTER_NONE; else png_ptr->do_filter = PNG_ALL_FILTERS; } png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */ } /* Write the palette. We are careful not to trust png_color to be in the * correct order for PNG, so people can redefine it to any convenient * structure. */ void /* PRIVATE */ png_write_PLTE(png_structrp png_ptr, png_const_colorp palette, png_uint_32 num_pal) { png_uint_32 i; png_const_colorp pal_ptr; png_byte buf[3]; png_debug(1, "in png_write_PLTE"); if (( #ifdef PNG_MNG_FEATURES_SUPPORTED !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) && #endif num_pal == 0) || num_pal > 256) { if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) { png_error(png_ptr, "Invalid number of colors in palette"); } else { png_warning(png_ptr, "Invalid number of colors in palette"); return; } } if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR)) { png_warning(png_ptr, "Ignoring request to write a PLTE chunk in grayscale PNG"); return; } png_ptr->num_palette = (png_uint_16)num_pal; png_debug1(3, "num_palette = %d", png_ptr->num_palette); png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3)); #ifdef PNG_POINTER_INDEXING_SUPPORTED for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++) { buf[0] = pal_ptr->red; buf[1] = pal_ptr->green; buf[2] = pal_ptr->blue; png_write_chunk_data(png_ptr, buf, (png_size_t)3); } #else /* This is a little slower but some buggy compilers need to do this * instead */ pal_ptr=palette; for (i = 0; i < num_pal; i++) { buf[0] = pal_ptr[i].red; buf[1] = pal_ptr[i].green; buf[2] = pal_ptr[i].blue; png_write_chunk_data(png_ptr, buf, (png_size_t)3); } #endif png_write_chunk_end(png_ptr); png_ptr->mode |= PNG_HAVE_PLTE; } /* This is similar to png_text_compress, above, except that it does not require * all of the data at once and, instead of buffering the compressed result, * writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out * because it calls the write interface. As a result it does its own error * reporting and does not return an error code. In the event of error it will * just call png_error. The input data length may exceed 32-bits. The 'flush' * parameter is exactly the same as that to deflate, with the following * meanings: * * Z_NO_FLUSH: normal incremental output of compressed data * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up * * The routine manages the acquire and release of the png_ptr->zstream by * checking and (at the end) clearing png_ptr->zowner, it does some sanity * checks on the 'mode' flags while doing this. */ void /* PRIVATE */ png_compress_IDAT(png_structrp png_ptr, png_const_bytep input, png_alloc_size_t input_len, int flush) { if (png_ptr->zowner != png_IDAT) { /* First time. Ensure we have a temporary buffer for compression and * trim the buffer list if it has more than one entry to free memory. * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been * created at this point, but the check here is quick and safe. */ if (png_ptr->zbuffer_list == NULL) { png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp, png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr))); png_ptr->zbuffer_list->next = NULL; } else png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next); /* It is a terminal error if we can't claim the zstream. */ if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK) png_error(png_ptr, png_ptr->zstream.msg); /* The output state is maintained in png_ptr->zstream, so it must be * initialized here after the claim. */ png_ptr->zstream.next_out = png_ptr->zbuffer_list->output; png_ptr->zstream.avail_out = png_ptr->zbuffer_size; } /* Now loop reading and writing until all the input is consumed or an error * terminates the operation. The _out values are maintained across calls to * this function, but the input must be reset each time. */ png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); png_ptr->zstream.avail_in = 0; /* set below */ for (;;) { int ret; /* INPUT: from the row data */ uInt avail = ZLIB_IO_MAX; if (avail > input_len) avail = (uInt)input_len; /* safe because of the check */ png_ptr->zstream.avail_in = avail; input_len -= avail; ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush); /* Include as-yet unconsumed input */ input_len += png_ptr->zstream.avail_in; png_ptr->zstream.avail_in = 0; /* OUTPUT: write complete IDAT chunks when avail_out drops to zero, note * that these two zstream fields are preserved across the calls, therefore * there is no need to set these up on entry to the loop. */ if (png_ptr->zstream.avail_out == 0) { png_bytep data = png_ptr->zbuffer_list->output; uInt size = png_ptr->zbuffer_size; /* Write an IDAT containing the data then reset the buffer. The * first IDAT may need deflate header optimization. */ # ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED if (!(png_ptr->mode & PNG_HAVE_IDAT) && png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) optimize_cmf(data, png_image_size(png_ptr)); # endif png_write_complete_chunk(png_ptr, png_IDAT, data, size); png_ptr->mode |= PNG_HAVE_IDAT; png_ptr->zstream.next_out = data; png_ptr->zstream.avail_out = size; /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with * the same flush parameter until it has finished output, for NO_FLUSH * it doesn't matter. */ if (ret == Z_OK && flush != Z_NO_FLUSH) continue; } /* The order of these checks doesn't matter much; it just effect which * possible error might be detected if multiple things go wrong at once. */ if (ret == Z_OK) /* most likely return code! */ { /* If all the input has been consumed then just return. If Z_FINISH * was used as the flush parameter something has gone wrong if we get * here. */ if (input_len == 0) { if (flush == Z_FINISH) png_error(png_ptr, "Z_OK on Z_FINISH with output space"); return; } } else if (ret == Z_STREAM_END && flush == Z_FINISH) { /* This is the end of the IDAT data; any pending output must be * flushed. For small PNG files we may still be at the beginning. */ png_bytep data = png_ptr->zbuffer_list->output; uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out; # ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED if (!(png_ptr->mode & PNG_HAVE_IDAT) && png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) optimize_cmf(data, png_image_size(png_ptr)); # endif png_write_complete_chunk(png_ptr, png_IDAT, data, size); png_ptr->zstream.avail_out = 0; png_ptr->zstream.next_out = NULL; png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT; png_ptr->zowner = 0; /* Release the stream */ return; } else { /* This is an error condition. */ png_zstream_error(png_ptr, ret); png_error(png_ptr, png_ptr->zstream.msg); } } } /* Write an IEND chunk */ void /* PRIVATE */ png_write_IEND(png_structrp png_ptr) { png_debug(1, "in png_write_IEND"); png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0); png_ptr->mode |= PNG_HAVE_IEND; } #ifdef PNG_WRITE_gAMA_SUPPORTED /* Write a gAMA chunk */ void /* PRIVATE */ png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma) { png_byte buf[4]; png_debug(1, "in png_write_gAMA"); /* file_gamma is saved in 1/100,000ths */ png_save_uint_32(buf, (png_uint_32)file_gamma); png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4); } #endif #ifdef PNG_WRITE_sRGB_SUPPORTED /* Write a sRGB chunk */ void /* PRIVATE */ png_write_sRGB(png_structrp png_ptr, int srgb_intent) { png_byte buf[1]; png_debug(1, "in png_write_sRGB"); if (srgb_intent >= PNG_sRGB_INTENT_LAST) png_warning(png_ptr, "Invalid sRGB rendering intent specified"); buf[0]=(png_byte)srgb_intent; png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1); } #endif #ifdef PNG_WRITE_iCCP_SUPPORTED /* Write an iCCP chunk */ void /* PRIVATE */ png_write_iCCP(png_structrp png_ptr, png_const_charp name, png_const_bytep profile) { png_uint_32 name_len; png_uint_32 profile_len; png_byte new_name[81]; /* 1 byte for the compression byte */ compression_state comp; png_debug(1, "in png_write_iCCP"); /* These are all internal problems: the profile should have been checked * before when it was stored. */ if (profile == NULL) png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */ profile_len = png_get_uint_32(profile); if (profile_len < 132) png_error(png_ptr, "ICC profile too short"); if (profile_len & 0x03) png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)"); { png_uint_32 embedded_profile_len = png_get_uint_32(profile); if (profile_len != embedded_profile_len) png_error(png_ptr, "Profile length does not match profile"); } name_len = png_check_keyword(png_ptr, name, new_name); if (name_len == 0) png_error(png_ptr, "iCCP: invalid keyword"); new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE; /* Make sure we include the NULL after the name and the compression type */ ++name_len; png_text_compress_init(&comp, profile, profile_len); /* Allow for keyword terminator and compression byte */ if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK) png_error(png_ptr, png_ptr->zstream.msg); png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len); png_write_chunk_data(png_ptr, new_name, name_len); png_write_compressed_data_out(png_ptr, &comp); png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_sPLT_SUPPORTED /* Write a sPLT chunk */ void /* PRIVATE */ png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette) { png_uint_32 name_len; png_byte new_name[80]; png_byte entrybuf[10]; png_size_t entry_size = (spalette->depth == 8 ? 6 : 10); png_size_t palette_size = entry_size * spalette->nentries; png_sPLT_entryp ep; #ifndef PNG_POINTER_INDEXING_SUPPORTED int i; #endif png_debug(1, "in png_write_sPLT"); name_len = png_check_keyword(png_ptr, spalette->name, new_name); if (name_len == 0) png_error(png_ptr, "sPLT: invalid keyword"); /* Make sure we include the NULL after the name */ png_write_chunk_header(png_ptr, png_sPLT, (png_uint_32)(name_len + 2 + palette_size)); png_write_chunk_data(png_ptr, (png_bytep)new_name, (png_size_t)(name_len + 1)); png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1); /* Loop through each palette entry, writing appropriately */ #ifdef PNG_POINTER_INDEXING_SUPPORTED for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++) { if (spalette->depth == 8) { entrybuf[0] = (png_byte)ep->red; entrybuf[1] = (png_byte)ep->green; entrybuf[2] = (png_byte)ep->blue; entrybuf[3] = (png_byte)ep->alpha; png_save_uint_16(entrybuf + 4, ep->frequency); } else { png_save_uint_16(entrybuf + 0, ep->red); png_save_uint_16(entrybuf + 2, ep->green); png_save_uint_16(entrybuf + 4, ep->blue); png_save_uint_16(entrybuf + 6, ep->alpha); png_save_uint_16(entrybuf + 8, ep->frequency); } png_write_chunk_data(png_ptr, entrybuf, entry_size); } #else ep=spalette->entries; for (i = 0; i>spalette->nentries; i++) { if (spalette->depth == 8) { entrybuf[0] = (png_byte)ep[i].red; entrybuf[1] = (png_byte)ep[i].green; entrybuf[2] = (png_byte)ep[i].blue; entrybuf[3] = (png_byte)ep[i].alpha; png_save_uint_16(entrybuf + 4, ep[i].frequency); } else { png_save_uint_16(entrybuf + 0, ep[i].red); png_save_uint_16(entrybuf + 2, ep[i].green); png_save_uint_16(entrybuf + 4, ep[i].blue); png_save_uint_16(entrybuf + 6, ep[i].alpha); png_save_uint_16(entrybuf + 8, ep[i].frequency); } png_write_chunk_data(png_ptr, entrybuf, entry_size); } #endif png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_sBIT_SUPPORTED /* Write the sBIT chunk */ void /* PRIVATE */ png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type) { png_byte buf[4]; png_size_t size; png_debug(1, "in png_write_sBIT"); /* Make sure we don't depend upon the order of PNG_COLOR_8 */ if (color_type & PNG_COLOR_MASK_COLOR) { png_byte maxbits; maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 : png_ptr->usr_bit_depth); if (sbit->red == 0 || sbit->red > maxbits || sbit->green == 0 || sbit->green > maxbits || sbit->blue == 0 || sbit->blue > maxbits) { png_warning(png_ptr, "Invalid sBIT depth specified"); return; } buf[0] = sbit->red; buf[1] = sbit->green; buf[2] = sbit->blue; size = 3; } else { if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth) { png_warning(png_ptr, "Invalid sBIT depth specified"); return; } buf[0] = sbit->gray; size = 1; } if (color_type & PNG_COLOR_MASK_ALPHA) { if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth) { png_warning(png_ptr, "Invalid sBIT depth specified"); return; } buf[size++] = sbit->alpha; } png_write_complete_chunk(png_ptr, png_sBIT, buf, size); } #endif #ifdef PNG_WRITE_cHRM_SUPPORTED /* Write the cHRM chunk */ void /* PRIVATE */ png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy) { png_byte buf[32]; png_debug(1, "in png_write_cHRM"); /* Each value is saved in 1/100,000ths */ png_save_int_32(buf, xy->whitex); png_save_int_32(buf + 4, xy->whitey); png_save_int_32(buf + 8, xy->redx); png_save_int_32(buf + 12, xy->redy); png_save_int_32(buf + 16, xy->greenx); png_save_int_32(buf + 20, xy->greeny); png_save_int_32(buf + 24, xy->bluex); png_save_int_32(buf + 28, xy->bluey); png_write_complete_chunk(png_ptr, png_cHRM, buf, 32); } #endif #ifdef PNG_WRITE_tRNS_SUPPORTED /* Write the tRNS chunk */ void /* PRIVATE */ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha, png_const_color_16p tran, int num_trans, int color_type) { png_byte buf[6]; png_debug(1, "in png_write_tRNS"); if (color_type == PNG_COLOR_TYPE_PALETTE) { if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette) { png_app_warning(png_ptr, "Invalid number of transparent colors specified"); return; } /* Write the chunk out as it is */ png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, (png_size_t)num_trans); } else if (color_type == PNG_COLOR_TYPE_GRAY) { /* One 16 bit value */ if (tran->gray >= (1 << png_ptr->bit_depth)) { png_app_warning(png_ptr, "Ignoring attempt to write tRNS chunk out-of-range for bit_depth"); return; } png_save_uint_16(buf, tran->gray); png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2); } else if (color_type == PNG_COLOR_TYPE_RGB) { /* Three 16 bit values */ png_save_uint_16(buf, tran->red); png_save_uint_16(buf + 2, tran->green); png_save_uint_16(buf + 4, tran->blue); #ifdef PNG_WRITE_16BIT_SUPPORTED if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) #else if (buf[0] | buf[2] | buf[4]) #endif { png_app_warning(png_ptr, "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8"); return; } png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6); } else { png_app_warning(png_ptr, "Can't write tRNS with an alpha channel"); } } #endif #ifdef PNG_WRITE_bKGD_SUPPORTED /* Write the background chunk */ void /* PRIVATE */ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type) { png_byte buf[6]; png_debug(1, "in png_write_bKGD"); if (color_type == PNG_COLOR_TYPE_PALETTE) { if ( #ifdef PNG_MNG_FEATURES_SUPPORTED (png_ptr->num_palette || (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) && #endif back->index >= png_ptr->num_palette) { png_warning(png_ptr, "Invalid background palette index"); return; } buf[0] = back->index; png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1); } else if (color_type & PNG_COLOR_MASK_COLOR) { png_save_uint_16(buf, back->red); png_save_uint_16(buf + 2, back->green); png_save_uint_16(buf + 4, back->blue); #ifdef PNG_WRITE_16BIT_SUPPORTED if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) #else if (buf[0] | buf[2] | buf[4]) #endif { png_warning(png_ptr, "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8"); return; } png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6); } else { if (back->gray >= (1 << png_ptr->bit_depth)) { png_warning(png_ptr, "Ignoring attempt to write bKGD chunk out-of-range for bit_depth"); return; } png_save_uint_16(buf, back->gray); png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2); } } #endif #ifdef PNG_WRITE_hIST_SUPPORTED /* Write the histogram */ void /* PRIVATE */ png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist) { int i; png_byte buf[3]; png_debug(1, "in png_write_hIST"); if (num_hist > (int)png_ptr->num_palette) { png_debug2(3, "num_hist = %d, num_palette = %d", num_hist, png_ptr->num_palette); png_warning(png_ptr, "Invalid number of histogram entries specified"); return; } png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2)); for (i = 0; i < num_hist; i++) { png_save_uint_16(buf, hist[i]); png_write_chunk_data(png_ptr, buf, (png_size_t)2); } png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_tEXt_SUPPORTED /* Write a tEXt chunk */ void /* PRIVATE */ png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, png_size_t text_len) { png_uint_32 key_len; png_byte new_key[80]; png_debug(1, "in png_write_tEXt"); key_len = png_check_keyword(png_ptr, key, new_key); if (key_len == 0) png_error(png_ptr, "tEXt: invalid keyword"); if (text == NULL || *text == '\0') text_len = 0; else text_len = strlen(text); if (text_len > PNG_UINT_31_MAX - (key_len+1)) png_error(png_ptr, "tEXt: text too long"); /* Make sure we include the 0 after the key */ png_write_chunk_header(png_ptr, png_tEXt, (png_uint_32)/*checked above*/(key_len + text_len + 1)); /* * We leave it to the application to meet PNG-1.0 requirements on the * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them. * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. */ png_write_chunk_data(png_ptr, new_key, key_len + 1); if (text_len) png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len); png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_zTXt_SUPPORTED /* Write a compressed text chunk */ void /* PRIVATE */ png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, png_size_t text_len, int compression) { png_uint_32 key_len; png_byte new_key[81]; compression_state comp; png_debug(1, "in png_write_zTXt"); PNG_UNUSED(text_len) /* Always use strlen */ if (compression == PNG_TEXT_COMPRESSION_NONE) { png_write_tEXt(png_ptr, key, text, 0); return; } if (compression != PNG_TEXT_COMPRESSION_zTXt) png_error(png_ptr, "zTXt: invalid compression type"); key_len = png_check_keyword(png_ptr, key, new_key); if (key_len == 0) png_error(png_ptr, "zTXt: invalid keyword"); /* Add the compression method and 1 for the keyword separator. */ new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE; ++key_len; /* Compute the compressed data; do it now for the length */ png_text_compress_init(&comp, (png_const_bytep)text, text == NULL ? 0 : strlen(text)); if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK) png_error(png_ptr, png_ptr->zstream.msg); /* Write start of chunk */ png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len); /* Write key */ png_write_chunk_data(png_ptr, new_key, key_len); /* Write the compressed data */ png_write_compressed_data_out(png_ptr, &comp); /* Close the chunk */ png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_iTXt_SUPPORTED /* Write an iTXt chunk */ void /* PRIVATE */ png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key, png_const_charp lang, png_const_charp lang_key, png_const_charp text) { png_uint_32 key_len, prefix_len; png_size_t lang_len, lang_key_len; png_byte new_key[82]; compression_state comp; png_debug(1, "in png_write_iTXt"); key_len = png_check_keyword(png_ptr, key, new_key); if (key_len == 0) png_error(png_ptr, "iTXt: invalid keyword"); /* Set the compression flag */ switch (compression) { case PNG_ITXT_COMPRESSION_NONE: case PNG_TEXT_COMPRESSION_NONE: compression = new_key[++key_len] = 0; /* no compression */ break; case PNG_TEXT_COMPRESSION_zTXt: case PNG_ITXT_COMPRESSION_zTXt: compression = new_key[++key_len] = 1; /* compressed */ break; default: png_error(png_ptr, "iTXt: invalid compression"); } new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE; ++key_len; /* for the keywod separator */ /* We leave it to the application to meet PNG-1.0 requirements on the * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of * any non-Latin-1 characters except for NEWLINE. ISO PNG, however, * specifies that the text is UTF-8 and this really doesn't require any * checking. * * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. * * TODO: validate the language tag correctly (see the spec.) */ if (lang == NULL) lang = ""; /* empty language is valid */ lang_len = strlen(lang)+1; if (lang_key == NULL) lang_key = ""; /* may be empty */ lang_key_len = strlen(lang_key)+1; if (text == NULL) text = ""; /* may be empty */ prefix_len = key_len; if (lang_len > PNG_UINT_31_MAX-prefix_len) prefix_len = PNG_UINT_31_MAX; else prefix_len = (png_uint_32)(prefix_len + lang_len); if (lang_key_len > PNG_UINT_31_MAX-prefix_len) prefix_len = PNG_UINT_31_MAX; else prefix_len = (png_uint_32)(prefix_len + lang_key_len); png_text_compress_init(&comp, (png_const_bytep)text, strlen(text)); if (compression) { if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK) png_error(png_ptr, png_ptr->zstream.msg); } else { if (comp.input_len > PNG_UINT_31_MAX-prefix_len) png_error(png_ptr, "iTXt: uncompressed text too long"); /* So the string will fit in a chunk: */ comp.output_len = (png_uint_32)/*SAFE*/comp.input_len; } png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len); png_write_chunk_data(png_ptr, new_key, key_len); png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len); png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len); if (compression) png_write_compressed_data_out(png_ptr, &comp); else png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.input_len); png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_oFFs_SUPPORTED /* Write the oFFs chunk */ void /* PRIVATE */ png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset, int unit_type) { png_byte buf[9]; png_debug(1, "in png_write_oFFs"); if (unit_type >= PNG_OFFSET_LAST) png_warning(png_ptr, "Unrecognized unit type for oFFs chunk"); png_save_int_32(buf, x_offset); png_save_int_32(buf + 4, y_offset); buf[8] = (png_byte)unit_type; png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9); } #endif #ifdef PNG_WRITE_pCAL_SUPPORTED /* Write the pCAL chunk (described in the PNG extensions document) */ void /* PRIVATE */ png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams, png_const_charp units, png_charpp params) { png_uint_32 purpose_len; png_size_t units_len, total_len; png_size_tp params_len; png_byte buf[10]; png_byte new_purpose[80]; int i; png_debug1(1, "in png_write_pCAL (%d parameters)", nparams); if (type >= PNG_EQUATION_LAST) png_error(png_ptr, "Unrecognized equation type for pCAL chunk"); purpose_len = png_check_keyword(png_ptr, purpose, new_purpose); if (purpose_len == 0) png_error(png_ptr, "pCAL: invalid keyword"); ++purpose_len; /* terminator */ png_debug1(3, "pCAL purpose length = %d", (int)purpose_len); units_len = strlen(units) + (nparams == 0 ? 0 : 1); png_debug1(3, "pCAL units length = %d", (int)units_len); total_len = purpose_len + units_len + 10; params_len = (png_size_tp)png_malloc(png_ptr, (png_alloc_size_t)(nparams * (sizeof (png_size_t)))); /* Find the length of each parameter, making sure we don't count the * null terminator for the last parameter. */ for (i = 0; i < nparams; i++) { params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1); png_debug2(3, "pCAL parameter %d length = %lu", i, (unsigned long)params_len[i]); total_len += params_len[i]; } png_debug1(3, "pCAL total length = %d", (int)total_len); png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len); png_write_chunk_data(png_ptr, new_purpose, purpose_len); png_save_int_32(buf, X0); png_save_int_32(buf + 4, X1); buf[8] = (png_byte)type; buf[9] = (png_byte)nparams; png_write_chunk_data(png_ptr, buf, (png_size_t)10); png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len); for (i = 0; i < nparams; i++) { png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]); } png_free(png_ptr, params_len); png_write_chunk_end(png_ptr); } #endif #ifdef PNG_WRITE_sCAL_SUPPORTED /* Write the sCAL chunk */ void /* PRIVATE */ png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width, png_const_charp height) { png_byte buf[64]; png_size_t wlen, hlen, total_len; png_debug(1, "in png_write_sCAL_s"); wlen = strlen(width); hlen = strlen(height); total_len = wlen + hlen + 2; if (total_len > 64) { png_warning(png_ptr, "Can't write sCAL (buffer too small)"); return; } buf[0] = (png_byte)unit; memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */ memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */ png_debug1(3, "sCAL total length = %u", (unsigned int)total_len); png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len); } #endif #ifdef PNG_WRITE_pHYs_SUPPORTED /* Write the pHYs chunk */ void /* PRIVATE */ png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit, int unit_type) { png_byte buf[9]; png_debug(1, "in png_write_pHYs"); if (unit_type >= PNG_RESOLUTION_LAST) png_warning(png_ptr, "Unrecognized unit type for pHYs chunk"); png_save_uint_32(buf, x_pixels_per_unit); png_save_uint_32(buf + 4, y_pixels_per_unit); buf[8] = (png_byte)unit_type; png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9); } #endif #ifdef PNG_WRITE_tIME_SUPPORTED /* Write the tIME chunk. Use either png_convert_from_struct_tm() * or png_convert_from_time_t(), or fill in the structure yourself. */ void /* PRIVATE */ png_write_tIME(png_structrp png_ptr, png_const_timep mod_time) { png_byte buf[7]; png_debug(1, "in png_write_tIME"); if (mod_time->month > 12 || mod_time->month < 1 || mod_time->day > 31 || mod_time->day < 1 || mod_time->hour > 23 || mod_time->second > 60) { png_warning(png_ptr, "Invalid time specified for tIME chunk"); return; } png_save_uint_16(buf, mod_time->year); buf[2] = mod_time->month; buf[3] = mod_time->day; buf[4] = mod_time->hour; buf[5] = mod_time->minute; buf[6] = mod_time->second; png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7); } #endif /* Initializes the row writing capability of libpng */ void /* PRIVATE */ png_write_start_row(png_structrp png_ptr) { #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ /* Start of interlace block */ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; /* Offset to next interlace block */ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; /* Start of interlace block in the y direction */ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; /* Offset to next interlace block in the y direction */ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; #endif png_alloc_size_t buf_size; int usr_pixel_depth; png_debug(1, "in png_write_start_row"); usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth; buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1; /* 1.5.6: added to allow checking in the row write code. */ png_ptr->transformed_pixel_depth = png_ptr->pixel_depth; png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth; /* Set up row buffer */ png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size); png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE; #ifdef PNG_WRITE_FILTER_SUPPORTED /* Set up filtering buffer, if using this filter */ if (png_ptr->do_filter & PNG_FILTER_SUB) { png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1); png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB; } /* We only need to keep the previous row if we are using one of these. */ if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) { /* Set up previous row buffer */ png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size); if (png_ptr->do_filter & PNG_FILTER_UP) { png_ptr->up_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1); png_ptr->up_row[0] = PNG_FILTER_VALUE_UP; } if (png_ptr->do_filter & PNG_FILTER_AVG) { png_ptr->avg_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1); png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG; } if (png_ptr->do_filter & PNG_FILTER_PAETH) { png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1); png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH; } } #endif /* PNG_WRITE_FILTER_SUPPORTED */ #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* If interlaced, we need to set up width and height of pass */ if (png_ptr->interlaced) { if (!(png_ptr->transformations & PNG_INTERLACE)) { png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - png_pass_ystart[0]) / png_pass_yinc[0]; png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 - png_pass_start[0]) / png_pass_inc[0]; } else { png_ptr->num_rows = png_ptr->height; png_ptr->usr_width = png_ptr->width; } } else #endif { png_ptr->num_rows = png_ptr->height; png_ptr->usr_width = png_ptr->width; } } /* Internal use only. Called when finished processing a row of data. */ void /* PRIVATE */ png_write_finish_row(png_structrp png_ptr) { #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ /* Start of interlace block */ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; /* Offset to next interlace block */ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; /* Start of interlace block in the y direction */ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; /* Offset to next interlace block in the y direction */ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; #endif png_debug(1, "in png_write_finish_row"); /* Next row */ png_ptr->row_number++; /* See if we are done */ if (png_ptr->row_number < png_ptr->num_rows) return; #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* If interlaced, go to next pass */ if (png_ptr->interlaced) { png_ptr->row_number = 0; if (png_ptr->transformations & PNG_INTERLACE) { png_ptr->pass++; } else { /* Loop until we find a non-zero width or height pass */ do { png_ptr->pass++; if (png_ptr->pass >= 7) break; png_ptr->usr_width = (png_ptr->width + png_pass_inc[png_ptr->pass] - 1 - png_pass_start[png_ptr->pass]) / png_pass_inc[png_ptr->pass]; png_ptr->num_rows = (png_ptr->height + png_pass_yinc[png_ptr->pass] - 1 - png_pass_ystart[png_ptr->pass]) / png_pass_yinc[png_ptr->pass]; if (png_ptr->transformations & PNG_INTERLACE) break; } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0); } /* Reset the row above the image for the next pass */ if (png_ptr->pass < 7) { if (png_ptr->prev_row != NULL) memset(png_ptr->prev_row, 0, (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels* png_ptr->usr_bit_depth, png_ptr->width)) + 1); return; } } #endif /* If we get here, we've just written the last row, so we need to flush the compressor */ png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH); } #ifdef PNG_WRITE_INTERLACING_SUPPORTED /* Pick out the correct pixels for the interlace pass. * The basic idea here is to go through the row with a source * pointer and a destination pointer (sp and dp), and copy the * correct pixels for the pass. As the row gets compacted, * sp will always be >= dp, so we should never overwrite anything. * See the default: case for the easiest code to understand. */ void /* PRIVATE */ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass) { /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ /* Start of interlace block */ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; /* Offset to next interlace block */ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; png_debug(1, "in png_do_write_interlace"); /* We don't have to do anything on the last pass (6) */ if (pass < 6) { /* Each pixel depth is handled separately */ switch (row_info->pixel_depth) { case 1: { png_bytep sp; png_bytep dp; int shift; int d; int value; png_uint_32 i; png_uint_32 row_width = row_info->width; dp = row; d = 0; shift = 7; for (i = png_pass_start[pass]; i < row_width; i += png_pass_inc[pass]) { sp = row + (png_size_t)(i >> 3); value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01; d |= (value << shift); if (shift == 0) { shift = 7; *dp++ = (png_byte)d; d = 0; } else shift--; } if (shift != 7) *dp = (png_byte)d; break; } case 2: { png_bytep sp; png_bytep dp; int shift; int d; int value; png_uint_32 i; png_uint_32 row_width = row_info->width; dp = row; shift = 6; d = 0; for (i = png_pass_start[pass]; i < row_width; i += png_pass_inc[pass]) { sp = row + (png_size_t)(i >> 2); value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03; d |= (value << shift); if (shift == 0) { shift = 6; *dp++ = (png_byte)d; d = 0; } else shift -= 2; } if (shift != 6) *dp = (png_byte)d; break; } case 4: { png_bytep sp; png_bytep dp; int shift; int d; int value; png_uint_32 i; png_uint_32 row_width = row_info->width; dp = row; shift = 4; d = 0; for (i = png_pass_start[pass]; i < row_width; i += png_pass_inc[pass]) { sp = row + (png_size_t)(i >> 1); value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f; d |= (value << shift); if (shift == 0) { shift = 4; *dp++ = (png_byte)d; d = 0; } else shift -= 4; } if (shift != 4) *dp = (png_byte)d; break; } default: { png_bytep sp; png_bytep dp; png_uint_32 i; png_uint_32 row_width = row_info->width; png_size_t pixel_bytes; /* Start at the beginning */ dp = row; /* Find out how many bytes each pixel takes up */ pixel_bytes = (row_info->pixel_depth >> 3); /* Loop through the row, only looking at the pixels that matter */ for (i = png_pass_start[pass]; i < row_width; i += png_pass_inc[pass]) { /* Find out where the original pixel is */ sp = row + (png_size_t)i * pixel_bytes; /* Move the pixel */ if (dp != sp) memcpy(dp, sp, pixel_bytes); /* Next pixel */ dp += pixel_bytes; } break; } } /* Set new row width */ row_info->width = (row_info->width + png_pass_inc[pass] - 1 - png_pass_start[pass]) / png_pass_inc[pass]; row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width); } } #endif /* This filters the row, chooses which filter to use, if it has not already * been specified by the application, and then writes the row out with the * chosen filter. */ static void png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row, png_size_t row_bytes); #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1) #define PNG_HISHIFT 10 #define PNG_LOMASK ((png_uint_32)0xffffL) #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT)) void /* PRIVATE */ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info) { png_bytep best_row; #ifdef PNG_WRITE_FILTER_SUPPORTED png_bytep prev_row, row_buf; png_uint_32 mins, bpp; png_byte filter_to_do = png_ptr->do_filter; png_size_t row_bytes = row_info->rowbytes; #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED int num_p_filters = png_ptr->num_prev_filters; #endif png_debug(1, "in png_write_find_filter"); #ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS) { /* These will never be selected so we need not test them. */ filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH); } #endif /* Find out how many bytes offset each pixel is */ bpp = (row_info->pixel_depth + 7) >> 3; prev_row = png_ptr->prev_row; #endif best_row = png_ptr->row_buf; #ifdef PNG_WRITE_FILTER_SUPPORTED row_buf = best_row; mins = PNG_MAXSUM; /* The prediction method we use is to find which method provides the * smallest value when summing the absolute values of the distances * from zero, using anything >= 128 as negative numbers. This is known * as the "minimum sum of absolute differences" heuristic. Other * heuristics are the "weighted minimum sum of absolute differences" * (experimental and can in theory improve compression), and the "zlib * predictive" method (not implemented yet), which does test compressions * of lines using different filter methods, and then chooses the * (series of) filter(s) that give minimum compressed data size (VERY * computationally expensive). * * GRR 980525: consider also * * (1) minimum sum of absolute differences from running average (i.e., * keep running sum of non-absolute differences & count of bytes) * [track dispersion, too? restart average if dispersion too large?] * * (1b) minimum sum of absolute differences from sliding average, probably * with window size <= deflate window (usually 32K) * * (2) minimum sum of squared differences from zero or running average * (i.e., ~ root-mean-square approach) */ /* We don't need to test the 'no filter' case if this is the only filter * that has been chosen, as it doesn't actually do anything to the data. */ if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE) { png_bytep rp; png_uint_32 sum = 0; png_size_t i; int v; for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++) { v = *rp; sum += (v < 128) ? v : 256 - v; } #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { png_uint_32 sumhi, sumlo; int j; sumlo = sum & PNG_LOMASK; sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */ /* Reduce the sum if we match any of the previous rows */ for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE) { sumlo = (sumlo * png_ptr->filter_weights[j]) >> PNG_WEIGHT_SHIFT; sumhi = (sumhi * png_ptr->filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } /* Factor in the cost of this filter (this is here for completeness, * but it makes no sense to have a "cost" for the NONE filter, as * it has the minimum possible computational cost - none). */ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >> PNG_COST_SHIFT; sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >> PNG_COST_SHIFT; if (sumhi > PNG_HIMASK) sum = PNG_MAXSUM; else sum = (sumhi << PNG_HISHIFT) + sumlo; } #endif mins = sum; } /* Sub filter */ if (filter_to_do == PNG_FILTER_SUB) /* It's the only filter so no testing is needed */ { png_bytep rp, lp, dp; png_size_t i; for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; i++, rp++, dp++) { *dp = *rp; } for (lp = row_buf + 1; i < row_bytes; i++, rp++, lp++, dp++) { *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); } best_row = png_ptr->sub_row; } else if (filter_to_do & PNG_FILTER_SUB) { png_bytep rp, dp, lp; png_uint_32 sum = 0, lmins = mins; png_size_t i; int v; #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* We temporarily increase the "minimum sum" by the factor we * would reduce the sum of this filter, so that we can do the * early exit comparison without scaling the sum each time. */ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { int j; png_uint_32 lmhi, lmlo; lmlo = lmins & PNG_LOMASK; lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB) { lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> PNG_COST_SHIFT; lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> PNG_COST_SHIFT; if (lmhi > PNG_HIMASK) lmins = PNG_MAXSUM; else lmins = (lmhi << PNG_HISHIFT) + lmlo; } #endif for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; i++, rp++, dp++) { v = *dp = *rp; sum += (v < 128) ? v : 256 - v; } for (lp = row_buf + 1; i < row_bytes; i++, rp++, lp++, dp++) { v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); sum += (v < 128) ? v : 256 - v; if (sum > lmins) /* We are already worse, don't continue. */ break; } #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { int j; png_uint_32 sumhi, sumlo; sumlo = sum & PNG_LOMASK; sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB) { sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> PNG_COST_SHIFT; sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> PNG_COST_SHIFT; if (sumhi > PNG_HIMASK) sum = PNG_MAXSUM; else sum = (sumhi << PNG_HISHIFT) + sumlo; } #endif if (sum < mins) { mins = sum; best_row = png_ptr->sub_row; } } /* Up filter */ if (filter_to_do == PNG_FILTER_UP) { png_bytep rp, dp, pp; png_size_t i; for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, pp = prev_row + 1; i < row_bytes; i++, rp++, pp++, dp++) { *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff); } best_row = png_ptr->up_row; } else if (filter_to_do & PNG_FILTER_UP) { png_bytep rp, dp, pp; png_uint_32 sum = 0, lmins = mins; png_size_t i; int v; #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { int j; png_uint_32 lmhi, lmlo; lmlo = lmins & PNG_LOMASK; lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP) { lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >> PNG_COST_SHIFT; lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >> PNG_COST_SHIFT; if (lmhi > PNG_HIMASK) lmins = PNG_MAXSUM; else lmins = (lmhi << PNG_HISHIFT) + lmlo; } #endif for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, pp = prev_row + 1; i < row_bytes; i++) { v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); sum += (v < 128) ? v : 256 - v; if (sum > lmins) /* We are already worse, don't continue. */ break; } #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { int j; png_uint_32 sumhi, sumlo; sumlo = sum & PNG_LOMASK; sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP) { sumlo = (sumlo * png_ptr->filter_weights[j]) >> PNG_WEIGHT_SHIFT; sumhi = (sumhi * png_ptr->filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >> PNG_COST_SHIFT; sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >> PNG_COST_SHIFT; if (sumhi > PNG_HIMASK) sum = PNG_MAXSUM; else sum = (sumhi << PNG_HISHIFT) + sumlo; } #endif if (sum < mins) { mins = sum; best_row = png_ptr->up_row; } } /* Avg filter */ if (filter_to_do == PNG_FILTER_AVG) { png_bytep rp, dp, pp, lp; png_uint_32 i; for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, pp = prev_row + 1; i < bpp; i++) { *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); } for (lp = row_buf + 1; i < row_bytes; i++) { *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff); } best_row = png_ptr->avg_row; } else if (filter_to_do & PNG_FILTER_AVG) { png_bytep rp, dp, pp, lp; png_uint_32 sum = 0, lmins = mins; png_size_t i; int v; #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { int j; png_uint_32 lmhi, lmlo; lmlo = lmins & PNG_LOMASK; lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG) { lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >> PNG_COST_SHIFT; lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >> PNG_COST_SHIFT; if (lmhi > PNG_HIMASK) lmins = PNG_MAXSUM; else lmins = (lmhi << PNG_HISHIFT) + lmlo; } #endif for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, pp = prev_row + 1; i < bpp; i++) { v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); sum += (v < 128) ? v : 256 - v; } for (lp = row_buf + 1; i < row_bytes; i++) { v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff); sum += (v < 128) ? v : 256 - v; if (sum > lmins) /* We are already worse, don't continue. */ break; } #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { int j; png_uint_32 sumhi, sumlo; sumlo = sum & PNG_LOMASK; sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE) { sumlo = (sumlo * png_ptr->filter_weights[j]) >> PNG_WEIGHT_SHIFT; sumhi = (sumhi * png_ptr->filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >> PNG_COST_SHIFT; sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >> PNG_COST_SHIFT; if (sumhi > PNG_HIMASK) sum = PNG_MAXSUM; else sum = (sumhi << PNG_HISHIFT) + sumlo; } #endif if (sum < mins) { mins = sum; best_row = png_ptr->avg_row; } } /* Paeth filter */ if (filter_to_do == PNG_FILTER_PAETH) { png_bytep rp, dp, pp, cp, lp; png_size_t i; for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, pp = prev_row + 1; i < bpp; i++) { *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); } for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) { int a, b, c, pa, pb, pc, p; b = *pp++; c = *cp++; a = *lp++; p = b - c; pc = a - c; #ifdef PNG_USE_ABS pa = abs(p); pb = abs(pc); pc = abs(p + pc); #else pa = p < 0 ? -p : p; pb = pc < 0 ? -pc : pc; pc = (p + pc) < 0 ? -(p + pc) : p + pc; #endif p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); } best_row = png_ptr->paeth_row; } else if (filter_to_do & PNG_FILTER_PAETH) { png_bytep rp, dp, pp, cp, lp; png_uint_32 sum = 0, lmins = mins; png_size_t i; int v; #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { int j; png_uint_32 lmhi, lmlo; lmlo = lmins & PNG_LOMASK; lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH) { lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >> PNG_COST_SHIFT; lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >> PNG_COST_SHIFT; if (lmhi > PNG_HIMASK) lmins = PNG_MAXSUM; else lmins = (lmhi << PNG_HISHIFT) + lmlo; } #endif for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, pp = prev_row + 1; i < bpp; i++) { v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); sum += (v < 128) ? v : 256 - v; } for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) { int a, b, c, pa, pb, pc, p; b = *pp++; c = *cp++; a = *lp++; #ifndef PNG_SLOW_PAETH p = b - c; pc = a - c; #ifdef PNG_USE_ABS pa = abs(p); pb = abs(pc); pc = abs(p + pc); #else pa = p < 0 ? -p : p; pb = pc < 0 ? -pc : pc; pc = (p + pc) < 0 ? -(p + pc) : p + pc; #endif p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; #else /* PNG_SLOW_PAETH */ p = a + b - c; pa = abs(p - a); pb = abs(p - b); pc = abs(p - c); if (pa <= pb && pa <= pc) p = a; else if (pb <= pc) p = b; else p = c; #endif /* PNG_SLOW_PAETH */ v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); sum += (v < 128) ? v : 256 - v; if (sum > lmins) /* We are already worse, don't continue. */ break; } #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) { int j; png_uint_32 sumhi, sumlo; sumlo = sum & PNG_LOMASK; sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; for (j = 0; j < num_p_filters; j++) { if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH) { sumlo = (sumlo * png_ptr->filter_weights[j]) >> PNG_WEIGHT_SHIFT; sumhi = (sumhi * png_ptr->filter_weights[j]) >> PNG_WEIGHT_SHIFT; } } sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >> PNG_COST_SHIFT; sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >> PNG_COST_SHIFT; if (sumhi > PNG_HIMASK) sum = PNG_MAXSUM; else sum = (sumhi << PNG_HISHIFT) + sumlo; } #endif if (sum < mins) { best_row = png_ptr->paeth_row; } } #endif /* PNG_WRITE_FILTER_SUPPORTED */ /* Do the actual writing of the filtered row data from the chosen filter. */ png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1); #ifdef PNG_WRITE_FILTER_SUPPORTED #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* Save the type of filter we picked this time for future calculations */ if (png_ptr->num_prev_filters > 0) { int j; for (j = 1; j < num_p_filters; j++) { png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1]; } png_ptr->prev_filters[j] = best_row[0]; } #endif #endif /* PNG_WRITE_FILTER_SUPPORTED */ } /* Do the actual writing of a previously filtered row. */ static void png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row, png_size_t full_row_length/*includes filter byte*/) { png_debug(1, "in png_write_filtered_row"); png_debug1(2, "filter = %d", filtered_row[0]); png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH); /* Swap the current and previous rows */ if (png_ptr->prev_row != NULL) { png_bytep tptr; tptr = png_ptr->prev_row; png_ptr->prev_row = png_ptr->row_buf; png_ptr->row_buf = tptr; } /* Finish row - updates counters and flushes zlib if last row */ png_write_finish_row(png_ptr); #ifdef PNG_WRITE_FLUSH_SUPPORTED png_ptr->flush_rows++; if (png_ptr->flush_dist > 0 && png_ptr->flush_rows >= png_ptr->flush_dist) { png_write_flush(png_ptr); } #endif } #endif /* PNG_WRITE_SUPPORTED */