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Diffstat (limited to 'src/libpng/pngwutil.c')
| -rw-r--r-- | src/libpng/pngwutil.c | 2792 |
1 files changed, 2792 insertions, 0 deletions
diff --git a/src/libpng/pngwutil.c b/src/libpng/pngwutil.c new file mode 100644 index 0000000..fef38ae --- /dev/null +++ b/src/libpng/pngwutil.c @@ -0,0 +1,2792 @@ + +/* pngwutil.c - utilities to write a PNG file + * + * Last changed in libpng 1.2.20 Septhember 3, 2007 + * For conditions of distribution and use, see copyright notice in png.h + * Copyright (c) 1998-2007 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.) + */ + +#define PNG_INTERNAL +#include "png.h" +#ifdef PNG_WRITE_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); +} + +/* The png_save_int_32 function assumes integers are stored in two's + * complement format. If this isn't the case, then this routine needs to + * be modified to write data in two's complement format. + */ +void PNGAPI +png_save_int_32(png_bytep buf, png_int_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); +} + +/* 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. + */ +void PNGAPI +png_write_chunk(png_structp png_ptr, png_bytep chunk_name, + png_bytep data, png_size_t length) +{ + if(png_ptr == NULL) return; + png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length); + png_write_chunk_data(png_ptr, data, length); + png_write_chunk_end(png_ptr); +} + +/* 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(). + */ +void PNGAPI +png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name, + png_uint_32 length) +{ + png_byte buf[4]; + png_debug2(0, "Writing %s chunk (%lu bytes)\n", chunk_name, length); + if(png_ptr == NULL) return; + + /* write the length */ + png_save_uint_32(buf, length); + png_write_data(png_ptr, buf, (png_size_t)4); + + /* write the chunk name */ + png_write_data(png_ptr, chunk_name, (png_size_t)4); + /* reset the crc and run it over the chunk name */ + png_reset_crc(png_ptr); + png_calculate_crc(png_ptr, chunk_name, (png_size_t)4); +} + +/* Write the data of a PNG chunk started with png_write_chunk_start(). + * 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_start(). + */ +void PNGAPI +png_write_chunk_data(png_structp png_ptr, png_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_calculate_crc(png_ptr, data, length); + png_write_data(png_ptr, data, length); + } +} + +/* Finish a chunk started with png_write_chunk_start(). */ +void PNGAPI +png_write_chunk_end(png_structp png_ptr) +{ + png_byte buf[4]; + + if(png_ptr == NULL) return; + + /* write the crc */ + png_save_uint_32(buf, png_ptr->crc); + + png_write_data(png_ptr, buf, (png_size_t)4); +} + +/* 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 /* PRIVATE */ +png_write_sig(png_structp png_ptr) +{ + png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; + /* 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; +} + +#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_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 in order to make the whole mess thread-safe. + */ + +typedef struct +{ + char *input; /* the uncompressed input data */ + int input_len; /* its length */ + int num_output_ptr; /* number of output pointers used */ + int max_output_ptr; /* size of output_ptr */ + png_charpp output_ptr; /* array of pointers to output */ +} compression_state; + +/* compress given text into storage in the png_ptr structure */ +static int /* PRIVATE */ +png_text_compress(png_structp png_ptr, + png_charp text, png_size_t text_len, int compression, + compression_state *comp) +{ + int ret; + + comp->num_output_ptr = 0; + comp->max_output_ptr = 0; + comp->output_ptr = NULL; + comp->input = NULL; + comp->input_len = 0; + + /* we may just want to pass the text right through */ + if (compression == PNG_TEXT_COMPRESSION_NONE) + { + comp->input = text; + comp->input_len = text_len; + return((int)text_len); + } + + if (compression >= PNG_TEXT_COMPRESSION_LAST) + { +#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE) + char msg[50]; + png_snprintf(msg, 50, "Unknown compression type %d", compression); + png_warning(png_ptr, msg); +#else + png_warning(png_ptr, "Unknown compression type"); +#endif + } + + /* We can't write the chunk until we find out how much data we have, + * which means we need to run the compressor first and save the + * output. This shouldn't be a problem, as the vast majority of + * comments should be reasonable, but we will set up an array of + * malloc'd pointers to be sure. + * + * If we knew the application was well behaved, we could simplify this + * greatly by assuming we can always malloc an output buffer large + * enough to hold the compressed text ((1001 * text_len / 1000) + 12) + * and malloc this directly. The only time this would be a bad idea is + * if we can't malloc more than 64K and we have 64K of random input + * data, or if the input string is incredibly large (although this + * wouldn't cause a failure, just a slowdown due to swapping). + */ + + /* set up the compression buffers */ + png_ptr->zstream.avail_in = (uInt)text_len; + png_ptr->zstream.next_in = (Bytef *)text; + png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; + png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf; + + /* this is the same compression loop as in png_write_row() */ + do + { + /* compress the data */ + ret = deflate(&png_ptr->zstream, Z_NO_FLUSH); + if (ret != Z_OK) + { + /* error */ + if (png_ptr->zstream.msg != NULL) + png_error(png_ptr, png_ptr->zstream.msg); + else + png_error(png_ptr, "zlib error"); + } + /* check to see if we need more room */ + if (!(png_ptr->zstream.avail_out)) + { + /* make sure the output array has room */ + if (comp->num_output_ptr >= comp->max_output_ptr) + { + int old_max; + + old_max = comp->max_output_ptr; + comp->max_output_ptr = comp->num_output_ptr + 4; + if (comp->output_ptr != NULL) + { + png_charpp old_ptr; + + old_ptr = comp->output_ptr; + comp->output_ptr = (png_charpp)png_malloc(png_ptr, + (png_uint_32)(comp->max_output_ptr * + png_sizeof (png_charpp))); + png_memcpy(comp->output_ptr, old_ptr, old_max + * png_sizeof (png_charp)); + png_free(png_ptr, old_ptr); + } + else + comp->output_ptr = (png_charpp)png_malloc(png_ptr, + (png_uint_32)(comp->max_output_ptr * + png_sizeof (png_charp))); + } + + /* save the data */ + comp->output_ptr[comp->num_output_ptr] = (png_charp)png_malloc(png_ptr, + (png_uint_32)png_ptr->zbuf_size); + png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf, + png_ptr->zbuf_size); + comp->num_output_ptr++; + + /* and reset the buffer */ + png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; + png_ptr->zstream.next_out = png_ptr->zbuf; + } + /* continue until we don't have any more to compress */ + } while (png_ptr->zstream.avail_in); + + /* finish the compression */ + do + { + /* tell zlib we are finished */ + ret = deflate(&png_ptr->zstream, Z_FINISH); + + if (ret == Z_OK) + { + /* check to see if we need more room */ + if (!(png_ptr->zstream.avail_out)) + { + /* check to make sure our output array has room */ + if (comp->num_output_ptr >= comp->max_output_ptr) + { + int old_max; + + old_max = comp->max_output_ptr; + comp->max_output_ptr = comp->num_output_ptr + 4; + if (comp->output_ptr != NULL) + { + png_charpp old_ptr; + + old_ptr = comp->output_ptr; + /* This could be optimized to realloc() */ + comp->output_ptr = (png_charpp)png_malloc(png_ptr, + (png_uint_32)(comp->max_output_ptr * + png_sizeof (png_charpp))); + png_memcpy(comp->output_ptr, old_ptr, + old_max * png_sizeof (png_charp)); + png_free(png_ptr, old_ptr); + } + else + comp->output_ptr = (png_charpp)png_malloc(png_ptr, + (png_uint_32)(comp->max_output_ptr * + png_sizeof (png_charp))); + } + + /* save off the data */ + comp->output_ptr[comp->num_output_ptr] = + (png_charp)png_malloc(png_ptr, (png_uint_32)png_ptr->zbuf_size); + png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf, + png_ptr->zbuf_size); + comp->num_output_ptr++; + + /* and reset the buffer pointers */ + png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; + png_ptr->zstream.next_out = png_ptr->zbuf; + } + } + else if (ret != Z_STREAM_END) + { + /* we got an error */ + if (png_ptr->zstream.msg != NULL) + png_error(png_ptr, png_ptr->zstream.msg); + else + png_error(png_ptr, "zlib error"); + } + } while (ret != Z_STREAM_END); + + /* text length is number of buffers plus last buffer */ + text_len = png_ptr->zbuf_size * comp->num_output_ptr; + if (png_ptr->zstream.avail_out < png_ptr->zbuf_size) + text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out; + + return((int)text_len); +} + +/* ship the compressed text out via chunk writes */ +static void /* PRIVATE */ +png_write_compressed_data_out(png_structp png_ptr, compression_state *comp) +{ + int i; + + /* handle the no-compression case */ + if (comp->input) + { + png_write_chunk_data(png_ptr, (png_bytep)comp->input, + (png_size_t)comp->input_len); + return; + } + + /* write saved output buffers, if any */ + for (i = 0; i < comp->num_output_ptr; i++) + { + png_write_chunk_data(png_ptr,(png_bytep)comp->output_ptr[i], + png_ptr->zbuf_size); + png_free(png_ptr, comp->output_ptr[i]); + comp->output_ptr[i]=NULL; + } + if (comp->max_output_ptr != 0) + png_free(png_ptr, comp->output_ptr); + comp->output_ptr=NULL; + /* write anything left in zbuf */ + if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size) + png_write_chunk_data(png_ptr, png_ptr->zbuf, + png_ptr->zbuf_size - png_ptr->zstream.avail_out); + + /* reset zlib for another zTXt/iTXt or image data */ + deflateReset(&png_ptr->zstream); + png_ptr->zstream.data_type = Z_BINARY; +} +#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_structp 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) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_IHDR; +#endif + png_byte buf[13]; /* buffer to store the IHDR info */ + + png_debug(1, "in png_write_IHDR\n"); + /* 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: + case 16: png_ptr->channels = 1; break; + default: png_error(png_ptr,"Invalid bit depth for grayscale image"); + } + break; + case PNG_COLOR_TYPE_RGB: + if (bit_depth != 8 && bit_depth != 16) + 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: + if (bit_depth != 8 && bit_depth != 16) + 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 ( +#if defined(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 off 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; +#if defined(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_chunk(png_ptr, png_IHDR, buf, (png_size_t)13); + + /* initialize zlib with PNG info */ + png_ptr->zstream.zalloc = png_zalloc; + png_ptr->zstream.zfree = png_zfree; + png_ptr->zstream.opaque = (voidpf)png_ptr; + 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; + } + if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)) + { + if (png_ptr->do_filter != PNG_FILTER_NONE) + png_ptr->zlib_strategy = Z_FILTERED; + else + png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY; + } + if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL)) + png_ptr->zlib_level = Z_DEFAULT_COMPRESSION; + if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL)) + png_ptr->zlib_mem_level = 8; + if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS)) + png_ptr->zlib_window_bits = 15; + if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD)) + png_ptr->zlib_method = 8; + if (deflateInit2(&png_ptr->zstream, png_ptr->zlib_level, + png_ptr->zlib_method, png_ptr->zlib_window_bits, + png_ptr->zlib_mem_level, png_ptr->zlib_strategy) != Z_OK) + png_error(png_ptr, "zlib failed to initialize compressor"); + png_ptr->zstream.next_out = png_ptr->zbuf; + png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; + /* libpng is not interested in zstream.data_type */ + /* set it to a predefined value, to avoid its evaluation inside zlib */ + png_ptr->zstream.data_type = Z_BINARY; + + png_ptr->mode = PNG_HAVE_IHDR; +} + +/* 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_structp png_ptr, png_colorp palette, png_uint_32 num_pal) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_PLTE; +#endif + png_uint_32 i; + png_colorp pal_ptr; + png_byte buf[3]; + + png_debug(1, "in png_write_PLTE\n"); + if (( +#if defined(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\n", png_ptr->num_palette); + + png_write_chunk_start(png_ptr, png_PLTE, num_pal * 3); +#ifndef PNG_NO_POINTER_INDEXING + 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; +} + +/* write an IDAT chunk */ +void /* PRIVATE */ +png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_IDAT; +#endif + png_debug(1, "in png_write_IDAT\n"); + + /* Optimize the CMF field in the zlib stream. */ + /* This hack of the zlib stream is compliant to the stream specification. */ + if (!(png_ptr->mode & PNG_HAVE_IDAT) && + png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) + { + unsigned int z_cmf = data[0]; /* zlib compression method and flags */ + if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70) + { + /* Avoid memory underflows and multiplication overflows. */ + /* The conditions below are practically always satisfied; + however, they still must be checked. */ + if (length >= 2 && + png_ptr->height < 16384 && png_ptr->width < 16384) + { + png_uint_32 uncompressed_idat_size = png_ptr->height * + ((png_ptr->width * + png_ptr->channels * png_ptr->bit_depth + 15) >> 3); + unsigned int z_cinfo = z_cmf >> 4; + unsigned int half_z_window_size = 1 << (z_cinfo + 7); + while (uncompressed_idat_size <= half_z_window_size && + half_z_window_size >= 256) + { + z_cinfo--; + half_z_window_size >>= 1; + } + z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4); + if (data[0] != (png_byte)z_cmf) + { + data[0] = (png_byte)z_cmf; + data[1] &= 0xe0; + data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f); + } + } + } + else + png_error(png_ptr, + "Invalid zlib compression method or flags in IDAT"); + } + + png_write_chunk(png_ptr, png_IDAT, data, length); + png_ptr->mode |= PNG_HAVE_IDAT; +} + +/* write an IEND chunk */ +void /* PRIVATE */ +png_write_IEND(png_structp png_ptr) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_IEND; +#endif + png_debug(1, "in png_write_IEND\n"); + png_write_chunk(png_ptr, png_IEND, png_bytep_NULL, + (png_size_t)0); + png_ptr->mode |= PNG_HAVE_IEND; +} + +#if defined(PNG_WRITE_gAMA_SUPPORTED) +/* write a gAMA chunk */ +#ifdef PNG_FLOATING_POINT_SUPPORTED +void /* PRIVATE */ +png_write_gAMA(png_structp png_ptr, double file_gamma) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_gAMA; +#endif + png_uint_32 igamma; + png_byte buf[4]; + + png_debug(1, "in png_write_gAMA\n"); + /* file_gamma is saved in 1/100,000ths */ + igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5); + png_save_uint_32(buf, igamma); + png_write_chunk(png_ptr, png_gAMA, buf, (png_size_t)4); +} +#endif +#ifdef PNG_FIXED_POINT_SUPPORTED +void /* PRIVATE */ +png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_gAMA; +#endif + png_byte buf[4]; + + png_debug(1, "in png_write_gAMA\n"); + /* file_gamma is saved in 1/100,000ths */ + png_save_uint_32(buf, (png_uint_32)file_gamma); + png_write_chunk(png_ptr, png_gAMA, buf, (png_size_t)4); +} +#endif +#endif + +#if defined(PNG_WRITE_sRGB_SUPPORTED) +/* write a sRGB chunk */ +void /* PRIVATE */ +png_write_sRGB(png_structp png_ptr, int srgb_intent) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_sRGB; +#endif + png_byte buf[1]; + + png_debug(1, "in png_write_sRGB\n"); + if(srgb_intent >= PNG_sRGB_INTENT_LAST) + png_warning(png_ptr, + "Invalid sRGB rendering intent specified"); + buf[0]=(png_byte)srgb_intent; + png_write_chunk(png_ptr, png_sRGB, buf, (png_size_t)1); +} +#endif + +#if defined(PNG_WRITE_iCCP_SUPPORTED) +/* write an iCCP chunk */ +void /* PRIVATE */ +png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type, + png_charp profile, int profile_len) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_iCCP; +#endif + png_size_t name_len; + png_charp new_name; + compression_state comp; + int embedded_profile_len = 0; + + png_debug(1, "in png_write_iCCP\n"); + + comp.num_output_ptr = 0; + comp.max_output_ptr = 0; + comp.output_ptr = NULL; + comp.input = NULL; + comp.input_len = 0; + + if (name == NULL || (name_len = png_check_keyword(png_ptr, name, + &new_name)) == 0) + { + png_warning(png_ptr, "Empty keyword in iCCP chunk"); + return; + } + + if (compression_type != PNG_COMPRESSION_TYPE_BASE) + png_warning(png_ptr, "Unknown compression type in iCCP chunk"); + + if (profile == NULL) + profile_len = 0; + + if (profile_len > 3) + embedded_profile_len = + ((*( (png_bytep)profile ))<<24) | + ((*( (png_bytep)profile+1))<<16) | + ((*( (png_bytep)profile+2))<< 8) | + ((*( (png_bytep)profile+3)) ); + + if (profile_len < embedded_profile_len) + { + png_warning(png_ptr, + "Embedded profile length too large in iCCP chunk"); + return; + } + + if (profile_len > embedded_profile_len) + { + png_warning(png_ptr, + "Truncating profile to actual length in iCCP chunk"); + profile_len = embedded_profile_len; + } + + if (profile_len) + profile_len = png_text_compress(png_ptr, profile, (png_size_t)profile_len, + PNG_COMPRESSION_TYPE_BASE, &comp); + + /* make sure we include the NULL after the name and the compression type */ + png_write_chunk_start(png_ptr, png_iCCP, + (png_uint_32)name_len+profile_len+2); + new_name[name_len+1]=0x00; + png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 2); + + if (profile_len) + png_write_compressed_data_out(png_ptr, &comp); + + png_write_chunk_end(png_ptr); + png_free(png_ptr, new_name); +} +#endif + +#if defined(PNG_WRITE_sPLT_SUPPORTED) +/* write a sPLT chunk */ +void /* PRIVATE */ +png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_sPLT; +#endif + png_size_t name_len; + png_charp new_name; + png_byte entrybuf[10]; + int entry_size = (spalette->depth == 8 ? 6 : 10); + int palette_size = entry_size * spalette->nentries; + png_sPLT_entryp ep; +#ifdef PNG_NO_POINTER_INDEXING + int i; +#endif + + png_debug(1, "in png_write_sPLT\n"); + if (spalette->name == NULL || (name_len = png_check_keyword(png_ptr, + spalette->name, &new_name))==0) + { + png_warning(png_ptr, "Empty keyword in sPLT chunk"); + return; + } + + /* make sure we include the NULL after the name */ + png_write_chunk_start(png_ptr, png_sPLT, + (png_uint_32)(name_len + 2 + palette_size)); + png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 1); + png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, 1); + + /* loop through each palette entry, writing appropriately */ +#ifndef PNG_NO_POINTER_INDEXING + 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, (png_size_t)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); + png_free(png_ptr, new_name); +} +#endif + +#if defined(PNG_WRITE_sBIT_SUPPORTED) +/* write the sBIT chunk */ +void /* PRIVATE */ +png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_sBIT; +#endif + png_byte buf[4]; + png_size_t size; + + png_debug(1, "in png_write_sBIT\n"); + /* 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_chunk(png_ptr, png_sBIT, buf, size); +} +#endif + +#if defined(PNG_WRITE_cHRM_SUPPORTED) +/* write the cHRM chunk */ +#ifdef PNG_FLOATING_POINT_SUPPORTED +void /* PRIVATE */ +png_write_cHRM(png_structp png_ptr, double white_x, double white_y, + double red_x, double red_y, double green_x, double green_y, + double blue_x, double blue_y) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_cHRM; +#endif + png_byte buf[32]; + png_uint_32 itemp; + + png_debug(1, "in png_write_cHRM\n"); + /* each value is saved in 1/100,000ths */ + if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 || + white_x + white_y > 1.0) + { + png_warning(png_ptr, "Invalid cHRM white point specified"); +#if !defined(PNG_NO_CONSOLE_IO) + fprintf(stderr,"white_x=%f, white_y=%f\n",white_x, white_y); +#endif + return; + } + itemp = (png_uint_32)(white_x * 100000.0 + 0.5); + png_save_uint_32(buf, itemp); + itemp = (png_uint_32)(white_y * 100000.0 + 0.5); + png_save_uint_32(buf + 4, itemp); + + if (red_x < 0 || red_y < 0 || red_x + red_y > 1.0) + { + png_warning(png_ptr, "Invalid cHRM red point specified"); + return; + } + itemp = (png_uint_32)(red_x * 100000.0 + 0.5); + png_save_uint_32(buf + 8, itemp); + itemp = (png_uint_32)(red_y * 100000.0 + 0.5); + png_save_uint_32(buf + 12, itemp); + + if (green_x < 0 || green_y < 0 || green_x + green_y > 1.0) + { + png_warning(png_ptr, "Invalid cHRM green point specified"); + return; + } + itemp = (png_uint_32)(green_x * 100000.0 + 0.5); + png_save_uint_32(buf + 16, itemp); + itemp = (png_uint_32)(green_y * 100000.0 + 0.5); + png_save_uint_32(buf + 20, itemp); + + if (blue_x < 0 || blue_y < 0 || blue_x + blue_y > 1.0) + { + png_warning(png_ptr, "Invalid cHRM blue point specified"); + return; + } + itemp = (png_uint_32)(blue_x * 100000.0 + 0.5); + png_save_uint_32(buf + 24, itemp); + itemp = (png_uint_32)(blue_y * 100000.0 + 0.5); + png_save_uint_32(buf + 28, itemp); + + png_write_chunk(png_ptr, png_cHRM, buf, (png_size_t)32); +} +#endif +#ifdef PNG_FIXED_POINT_SUPPORTED +void /* PRIVATE */ +png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x, + png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y, + png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x, + png_fixed_point blue_y) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_cHRM; +#endif + png_byte buf[32]; + + png_debug(1, "in png_write_cHRM\n"); + /* each value is saved in 1/100,000ths */ + if (white_x > 80000L || white_y > 80000L || white_x + white_y > 100000L) + { + png_warning(png_ptr, "Invalid fixed cHRM white point specified"); +#if !defined(PNG_NO_CONSOLE_IO) + fprintf(stderr,"white_x=%ld, white_y=%ld\n",white_x, white_y); +#endif + return; + } + png_save_uint_32(buf, (png_uint_32)white_x); + png_save_uint_32(buf + 4, (png_uint_32)white_y); + + if (red_x + red_y > 100000L) + { + png_warning(png_ptr, "Invalid cHRM fixed red point specified"); + return; + } + png_save_uint_32(buf + 8, (png_uint_32)red_x); + png_save_uint_32(buf + 12, (png_uint_32)red_y); + + if (green_x + green_y > 100000L) + { + png_warning(png_ptr, "Invalid fixed cHRM green point specified"); + return; + } + png_save_uint_32(buf + 16, (png_uint_32)green_x); + png_save_uint_32(buf + 20, (png_uint_32)green_y); + + if (blue_x + blue_y > 100000L) + { + png_warning(png_ptr, "Invalid fixed cHRM blue point specified"); + return; + } + png_save_uint_32(buf + 24, (png_uint_32)blue_x); + png_save_uint_32(buf + 28, (png_uint_32)blue_y); + + png_write_chunk(png_ptr, png_cHRM, buf, (png_size_t)32); +} +#endif +#endif + +#if defined(PNG_WRITE_tRNS_SUPPORTED) +/* write the tRNS chunk */ +void /* PRIVATE */ +png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran, + int num_trans, int color_type) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_tRNS; +#endif + png_byte buf[6]; + + png_debug(1, "in png_write_tRNS\n"); + if (color_type == PNG_COLOR_TYPE_PALETTE) + { + if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette) + { + png_warning(png_ptr,"Invalid number of transparent colors specified"); + return; + } + /* write the chunk out as it is */ + png_write_chunk(png_ptr, png_tRNS, trans, (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_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_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); + if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) + { + png_warning(png_ptr, + "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8"); + return; + } + png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)6); + } + else + { + png_warning(png_ptr, "Can't write tRNS with an alpha channel"); + } +} +#endif + +#if defined(PNG_WRITE_bKGD_SUPPORTED) +/* write the background chunk */ +void /* PRIVATE */ +png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_bKGD; +#endif + png_byte buf[6]; + + png_debug(1, "in png_write_bKGD\n"); + if (color_type == PNG_COLOR_TYPE_PALETTE) + { + if ( +#if defined(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_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); + if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) + { + png_warning(png_ptr, + "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8"); + return; + } + png_write_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_chunk(png_ptr, png_bKGD, buf, (png_size_t)2); + } +} +#endif + +#if defined(PNG_WRITE_hIST_SUPPORTED) +/* write the histogram */ +void /* PRIVATE */ +png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_hIST; +#endif + int i; + png_byte buf[3]; + + png_debug(1, "in png_write_hIST\n"); + if (num_hist > (int)png_ptr->num_palette) + { + png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist, + png_ptr->num_palette); + png_warning(png_ptr, "Invalid number of histogram entries specified"); + return; + } + + png_write_chunk_start(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 + +#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 is allocated to hold the corrected keyword and must be freed + * by the calling routine. This avoids problems with trying to write to + * static keywords without having to have duplicate copies of the strings. + */ +png_size_t /* PRIVATE */ +png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key) +{ + png_size_t key_len; + png_charp kp, dp; + int kflag; + int kwarn=0; + + png_debug(1, "in png_check_keyword\n"); + *new_key = NULL; + + if (key == NULL || (key_len = png_strlen(key)) == 0) + { + png_warning(png_ptr, "zero length keyword"); + return ((png_size_t)0); + } + + png_debug1(2, "Keyword to be checked is '%s'\n", key); + + *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2)); + if (*new_key == NULL) + { + png_warning(png_ptr, "Out of memory while procesing keyword"); + return ((png_size_t)0); + } + + /* Replace non-printing characters with a blank and print a warning */ + for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++) + { + if ((png_byte)*kp < 0x20 || + ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1)) + { +#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE) + char msg[40]; + + png_snprintf(msg, 40, + "invalid keyword character 0x%02X", (png_byte)*kp); + png_warning(png_ptr, msg); +#else + png_warning(png_ptr, "invalid character in keyword"); +#endif + *dp = ' '; + } + else + { + *dp = *kp; + } + } + *dp = '\0'; + + /* Remove any trailing white space. */ + kp = *new_key + key_len - 1; + if (*kp == ' ') + { + png_warning(png_ptr, "trailing spaces removed from keyword"); + + while (*kp == ' ') + { + *(kp--) = '\0'; + key_len--; + } + } + + /* Remove any leading white space. */ + kp = *new_key; + if (*kp == ' ') + { + png_warning(png_ptr, "leading spaces removed from keyword"); + + while (*kp == ' ') + { + kp++; + key_len--; + } + } + + png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp); + + /* Remove multiple internal spaces. */ + for (kflag = 0, dp = *new_key; *kp != '\0'; kp++) + { + if (*kp == ' ' && kflag == 0) + { + *(dp++) = *kp; + kflag = 1; + } + else if (*kp == ' ') + { + key_len--; + kwarn=1; + } + else + { + *(dp++) = *kp; + kflag = 0; + } + } + *dp = '\0'; + if(kwarn) + png_warning(png_ptr, "extra interior spaces removed from keyword"); + + if (key_len == 0) + { + png_free(png_ptr, *new_key); + *new_key=NULL; + png_warning(png_ptr, "Zero length keyword"); + } + + if (key_len > 79) + { + png_warning(png_ptr, "keyword length must be 1 - 79 characters"); + new_key[79] = '\0'; + key_len = 79; + } + + return (key_len); +} +#endif + +#if defined(PNG_WRITE_tEXt_SUPPORTED) +/* write a tEXt chunk */ +void /* PRIVATE */ +png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text, + png_size_t text_len) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_tEXt; +#endif + png_size_t key_len; + png_charp new_key; + + png_debug(1, "in png_write_tEXt\n"); + if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0) + { + png_warning(png_ptr, "Empty keyword in tEXt chunk"); + return; + } + + if (text == NULL || *text == '\0') + text_len = 0; + else + text_len = png_strlen(text); + + /* make sure we include the 0 after the key */ + png_write_chunk_start(png_ptr, png_tEXt, (png_uint_32)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, (png_bytep)new_key, key_len + 1); + if (text_len) + png_write_chunk_data(png_ptr, (png_bytep)text, text_len); + + png_write_chunk_end(png_ptr); + png_free(png_ptr, new_key); +} +#endif + +#if defined(PNG_WRITE_zTXt_SUPPORTED) +/* write a compressed text chunk */ +void /* PRIVATE */ +png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text, + png_size_t text_len, int compression) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_zTXt; +#endif + png_size_t key_len; + char buf[1]; + png_charp new_key; + compression_state comp; + + png_debug(1, "in png_write_zTXt\n"); + + comp.num_output_ptr = 0; + comp.max_output_ptr = 0; + comp.output_ptr = NULL; + comp.input = NULL; + comp.input_len = 0; + + if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0) + { + png_warning(png_ptr, "Empty keyword in zTXt chunk"); + return; + } + + if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE) + { + png_write_tEXt(png_ptr, new_key, text, (png_size_t)0); + png_free(png_ptr, new_key); + return; + } + + text_len = png_strlen(text); + + /* compute the compressed data; do it now for the length */ + text_len = png_text_compress(png_ptr, text, text_len, compression, + &comp); + + /* write start of chunk */ + png_write_chunk_start(png_ptr, png_zTXt, (png_uint_32) + (key_len+text_len+2)); + /* write key */ + png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1); + png_free(png_ptr, new_key); + + buf[0] = (png_byte)compression; + /* write compression */ + png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1); + /* write the compressed data */ + png_write_compressed_data_out(png_ptr, &comp); + + /* close the chunk */ + png_write_chunk_end(png_ptr); +} +#endif + +#if defined(PNG_WRITE_iTXt_SUPPORTED) +/* write an iTXt chunk */ +void /* PRIVATE */ +png_write_iTXt(png_structp png_ptr, int compression, png_charp key, + png_charp lang, png_charp lang_key, png_charp text) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_iTXt; +#endif + png_size_t lang_len, key_len, lang_key_len, text_len; + png_charp new_lang, new_key; + png_byte cbuf[2]; + compression_state comp; + + png_debug(1, "in png_write_iTXt\n"); + + comp.num_output_ptr = 0; + comp.max_output_ptr = 0; + comp.output_ptr = NULL; + comp.input = NULL; + + if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0) + { + png_warning(png_ptr, "Empty keyword in iTXt chunk"); + return; + } + if (lang == NULL || (lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0) + { + png_warning(png_ptr, "Empty language field in iTXt chunk"); + new_lang = NULL; + lang_len = 0; + } + + if (lang_key == NULL) + lang_key_len = 0; + else + lang_key_len = png_strlen(lang_key); + + if (text == NULL) + text_len = 0; + else + text_len = png_strlen(text); + + /* compute the compressed data; do it now for the length */ + text_len = png_text_compress(png_ptr, text, text_len, compression-2, + &comp); + + + /* make sure we include the compression flag, the compression byte, + * and the NULs after the key, lang, and lang_key parts */ + + png_write_chunk_start(png_ptr, png_iTXt, + (png_uint_32)( + 5 /* comp byte, comp flag, terminators for key, lang and lang_key */ + + key_len + + lang_len + + lang_key_len + + text_len)); + + /* + * 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, (png_bytep)new_key, key_len + 1); + + /* set the compression flag */ + if (compression == PNG_ITXT_COMPRESSION_NONE || \ + compression == PNG_TEXT_COMPRESSION_NONE) + cbuf[0] = 0; + else /* compression == PNG_ITXT_COMPRESSION_zTXt */ + cbuf[0] = 1; + /* set the compression method */ + cbuf[1] = 0; + png_write_chunk_data(png_ptr, cbuf, 2); + + cbuf[0] = 0; + png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf), lang_len + 1); + png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf), lang_key_len + 1); + png_write_compressed_data_out(png_ptr, &comp); + + png_write_chunk_end(png_ptr); + png_free(png_ptr, new_key); + if (new_lang) + png_free(png_ptr, new_lang); +} +#endif + +#if defined(PNG_WRITE_oFFs_SUPPORTED) +/* write the oFFs chunk */ +void /* PRIVATE */ +png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset, + int unit_type) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_oFFs; +#endif + png_byte buf[9]; + + png_debug(1, "in png_write_oFFs\n"); + 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_chunk(png_ptr, png_oFFs, buf, (png_size_t)9); +} +#endif +#if defined(PNG_WRITE_pCAL_SUPPORTED) +/* write the pCAL chunk (described in the PNG extensions document) */ +void /* PRIVATE */ +png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0, + png_int_32 X1, int type, int nparams, png_charp units, png_charpp params) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_pCAL; +#endif + png_size_t purpose_len, units_len, total_len; + png_uint_32p params_len; + png_byte buf[10]; + png_charp new_purpose; + int i; + + png_debug1(1, "in png_write_pCAL (%d parameters)\n", nparams); + if (type >= PNG_EQUATION_LAST) + png_warning(png_ptr, "Unrecognized equation type for pCAL chunk"); + + purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1; + png_debug1(3, "pCAL purpose length = %d\n", (int)purpose_len); + units_len = png_strlen(units) + (nparams == 0 ? 0 : 1); + png_debug1(3, "pCAL units length = %d\n", (int)units_len); + total_len = purpose_len + units_len + 10; + + params_len = (png_uint_32p)png_malloc(png_ptr, (png_uint_32)(nparams + *png_sizeof(png_uint_32))); + + /* 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] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1); + png_debug2(3, "pCAL parameter %d length = %lu\n", i, params_len[i]); + total_len += (png_size_t)params_len[i]; + } + + png_debug1(3, "pCAL total length = %d\n", (int)total_len); + png_write_chunk_start(png_ptr, png_pCAL, (png_uint_32)total_len); + png_write_chunk_data(png_ptr, (png_bytep)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_bytep)units, (png_size_t)units_len); + + png_free(png_ptr, new_purpose); + + for (i = 0; i < nparams; i++) + { + png_write_chunk_data(png_ptr, (png_bytep)params[i], + (png_size_t)params_len[i]); + } + + png_free(png_ptr, params_len); + png_write_chunk_end(png_ptr); +} +#endif + +#if defined(PNG_WRITE_sCAL_SUPPORTED) +/* write the sCAL chunk */ +#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO) +void /* PRIVATE */ +png_write_sCAL(png_structp png_ptr, int unit, double width, double height) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_sCAL; +#endif + char buf[64]; + png_size_t total_len; + + png_debug(1, "in png_write_sCAL\n"); + + buf[0] = (char)unit; +#if defined(_WIN32_WCE) +/* sprintf() function is not supported on WindowsCE */ + { + wchar_t wc_buf[32]; + size_t wc_len; + swprintf(wc_buf, TEXT("%12.12e"), width); + wc_len = wcslen(wc_buf); + WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL, NULL); + total_len = wc_len + 2; + swprintf(wc_buf, TEXT("%12.12e"), height); + wc_len = wcslen(wc_buf); + WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + total_len, wc_len, + NULL, NULL); + total_len += wc_len; + } +#else + png_snprintf(buf + 1, 63, "%12.12e", width); + total_len = 1 + png_strlen(buf + 1) + 1; + png_snprintf(buf + total_len, 64-total_len, "%12.12e", height); + total_len += png_strlen(buf + total_len); +#endif + + png_debug1(3, "sCAL total length = %u\n", (unsigned int)total_len); + png_write_chunk(png_ptr, png_sCAL, (png_bytep)buf, total_len); +} +#else +#ifdef PNG_FIXED_POINT_SUPPORTED +void /* PRIVATE */ +png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width, + png_charp height) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_sCAL; +#endif + png_byte buf[64]; + png_size_t wlen, hlen, total_len; + + png_debug(1, "in png_write_sCAL_s\n"); + + wlen = png_strlen(width); + hlen = png_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; + png_memcpy(buf + 1, width, wlen + 1); /* append the '\0' here */ + png_memcpy(buf + wlen + 2, height, hlen); /* do NOT append the '\0' here */ + + png_debug1(3, "sCAL total length = %u\n", (unsigned int)total_len); + png_write_chunk(png_ptr, png_sCAL, buf, total_len); +} +#endif +#endif +#endif + +#if defined(PNG_WRITE_pHYs_SUPPORTED) +/* write the pHYs chunk */ +void /* PRIVATE */ +png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit, + png_uint_32 y_pixels_per_unit, + int unit_type) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_pHYs; +#endif + png_byte buf[9]; + + png_debug(1, "in png_write_pHYs\n"); + 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_chunk(png_ptr, png_pHYs, buf, (png_size_t)9); +} +#endif + +#if defined(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_structp png_ptr, png_timep mod_time) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + PNG_tIME; +#endif + png_byte buf[7]; + + png_debug(1, "in png_write_tIME\n"); + 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_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_structp png_ptr) +{ +#ifdef PNG_WRITE_INTERLACING_SUPPORTED +#ifdef PNG_USE_LOCAL_ARRAYS + /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* start of interlace block */ + int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* offset to next interlace block */ + int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* start of interlace block in the y direction */ + int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* offset to next interlace block in the y direction */ + int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; +#endif +#endif + + png_size_t buf_size; + + png_debug(1, "in png_write_start_row\n"); + buf_size = (png_size_t)(PNG_ROWBYTES( + png_ptr->usr_channels*png_ptr->usr_bit_depth,png_ptr->width)+1); + + /* set up row buffer */ + png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size); + png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE; + +#ifndef PNG_NO_WRITE_FILTERING + /* 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_malloc(png_ptr, (png_uint_32)buf_size); + png_memset(png_ptr->prev_row, 0, 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_NO_WRITE_FILTERING */ + } + +#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; + } + png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; + png_ptr->zstream.next_out = png_ptr->zbuf; +} + +/* Internal use only. Called when finished processing a row of data. */ +void /* PRIVATE */ +png_write_finish_row(png_structp png_ptr) +{ +#ifdef PNG_WRITE_INTERLACING_SUPPORTED +#ifdef PNG_USE_LOCAL_ARRAYS + /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* start of interlace block */ + int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* offset to next interlace block */ + int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; + + /* start of interlace block in the y direction */ + int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; + + /* offset to next interlace block in the y direction */ + int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; +#endif +#endif + + int ret; + + png_debug(1, "in png_write_finish_row\n"); + /* 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) + png_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 */ + do + { + /* tell the compressor we are done */ + ret = deflate(&png_ptr->zstream, Z_FINISH); + /* check for an error */ + if (ret == Z_OK) + { + /* check to see if we need more room */ + if (!(png_ptr->zstream.avail_out)) + { + png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size); + png_ptr->zstream.next_out = png_ptr->zbuf; + png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; + } + } + else if (ret != Z_STREAM_END) + { + if (png_ptr->zstream.msg != NULL) + png_error(png_ptr, png_ptr->zstream.msg); + else + png_error(png_ptr, "zlib error"); + } + } while (ret != Z_STREAM_END); + + /* write any extra space */ + if (png_ptr->zstream.avail_out < png_ptr->zbuf_size) + { + png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size - + png_ptr->zstream.avail_out); + } + + deflateReset(&png_ptr->zstream); + png_ptr->zstream.data_type = Z_BINARY; +} + +#if defined(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) +{ +#ifdef PNG_USE_LOCAL_ARRAYS + /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */ + + /* start of interlace block */ + int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; + + /* offset to next interlace block */ + int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; +#endif + + png_debug(1, "in png_do_write_interlace\n"); + /* we don't have to do anything on the last pass (6) */ +#if defined(PNG_USELESS_TESTS_SUPPORTED) + if (row != NULL && row_info != NULL && pass < 6) +#else + if (pass < 6) +#endif + { + /* 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) + png_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. + */ +#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_structp png_ptr, png_row_infop row_info) +{ + png_bytep best_row; +#ifndef PNG_NO_WRITE_FILTER + png_bytep prev_row, row_buf; + png_uint_32 mins, bpp; + png_byte filter_to_do = png_ptr->do_filter; + png_uint_32 row_bytes = row_info->rowbytes; +#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) + int num_p_filters = (int)png_ptr->num_prev_filters; +#endif + + png_debug(1, "in png_write_find_filter\n"); + /* 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; +#ifndef PNG_NO_WRITE_FILTER + 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_uint_32 i; + int v; + + for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++) + { + v = *rp; + sum += (v < 128) ? v : 256 - v; + } + +#if defined(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_uint_32 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_uint_32 i; + int v; + +#if defined(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; + } + +#if defined(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_uint_32 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_uint_32 i; + int v; + + +#if defined(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; + } + +#if defined(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_uint_32 i; + int v; + +#if defined(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; + } + +#if defined(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_uint_32 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_uint_32 i; + int v; + +#if defined(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; + } + +#if defined(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_NO_WRITE_FILTER */ + /* Do the actual writing of the filtered row data from the chosen filter. */ + + png_write_filtered_row(png_ptr, best_row); + +#ifndef PNG_NO_WRITE_FILTER +#if defined(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_NO_WRITE_FILTER */ +} + + +/* Do the actual writing of a previously filtered row. */ +void /* PRIVATE */ +png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row) +{ + png_debug(1, "in png_write_filtered_row\n"); + png_debug1(2, "filter = %d\n", filtered_row[0]); + /* set up the zlib input buffer */ + + png_ptr->zstream.next_in = filtered_row; + png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1; + /* repeat until we have compressed all the data */ + do + { + int ret; /* return of zlib */ + + /* compress the data */ + ret = deflate(&png_ptr->zstream, Z_NO_FLUSH); + /* check for compression errors */ + if (ret != Z_OK) + { + if (png_ptr->zstream.msg != NULL) + png_error(png_ptr, png_ptr->zstream.msg); + else + png_error(png_ptr, "zlib error"); + } + + /* see if it is time to write another IDAT */ + if (!(png_ptr->zstream.avail_out)) + { + /* write the IDAT and reset the zlib output buffer */ + png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size); + png_ptr->zstream.next_out = png_ptr->zbuf; + png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size; + } + /* repeat until all data has been compressed */ + } while (png_ptr->zstream.avail_in); + + /* 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); + +#if defined(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 */ |