| |
| /* pngwutil.c - utilities to write a PNG file |
| * |
| * Last changed in libpng 1.7.0 [(PENDING RELEASE)] |
| * Copyright (c) 1998-2002,2004,2006-2016 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" |
| #define PNG_SRC_FILE PNG_SRC_FILE_pngwutil |
| |
| #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); |
| buf[1] = PNG_BYTE(i >> 16); |
| buf[2] = PNG_BYTE(i >> 8); |
| buf[3] = PNG_BYTE(i); |
| } |
| |
| /* 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); |
| buf[1] = PNG_BYTE(i); |
| } |
| #endif /* WRITE_INT_FUNCTIONS */ |
| |
| /* 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_voidp 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 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_voidp 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 maximum"); |
| |
| png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)/*SAFE*/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_voidp 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_const_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. |
| */ |
| const png_uint_32 h = png_ptr->height; |
| const png_uint_32 w = png_ptr->width; |
| const unsigned int pd = PNG_PIXEL_DEPTH(*png_ptr); |
| png_alloc_size_t rowbytes = PNG_ROWBYTES(pd, w); |
| |
| if (rowbytes < 32768 && h < 32768) |
| { |
| if (png_ptr->interlaced != 0) |
| { |
| /* Interlacing makes the image larger because of the replication of |
| * both the filter byte and the padding to a byte boundary. |
| */ |
| png_alloc_size_t cb_base; |
| int pass; |
| |
| for (cb_base=0, pass=0; pass<PNG_INTERLACE_ADAM7_PASSES; ++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 (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_const_structrp png_ptr, 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_check_byte(png_ptr, z_cmf); |
| tmp = data[1] & 0xe0; |
| tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f; |
| data[1] = png_check_byte(png_ptr, tmp); |
| } |
| } |
| } |
| |
| PNG_UNUSED(png_ptr) |
| } |
| #endif /* WRITE_OPTIMIZE_CMF */ |
| |
| /* Release memory used by the deflate mechanism */ |
| static void |
| png_deflateEnd(png_const_structrp png_ptr, z_stream *zs, int check) |
| { |
| if (zs->state != NULL) |
| { |
| int ret = deflateEnd(zs); |
| |
| /* Z_DATA_ERROR means there was pending output. */ |
| if ((ret != Z_OK && (check || ret != Z_DATA_ERROR)) || zs->state != NULL) |
| { |
| png_zstream_error(zs, ret); |
| |
| if (check) |
| png_error(png_ptr, zs->msg); |
| |
| else |
| png_warning(png_ptr, zs->msg); |
| |
| zs->state = NULL; |
| } |
| } |
| } |
| |
| /* compression_buffer (new in 1.6.0) is just a linked list of 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.) |
| * |
| * From 1.7.0 the size is fixed to the same as the (uncompressed) row buffer |
| * size. This avoids allocating a large chunk of memory when compressing small |
| * images. This type is also opaque outside this file. |
| */ |
| typedef struct png_compression_buffer |
| { |
| struct png_compression_buffer *next; |
| png_byte output[PNG_ROW_BUFFER_SIZE]; |
| } png_compression_buffer, *png_compression_bufferp; |
| |
| /* png_compression_buffer methods */ |
| /* Deleting a compression buffer deletes the whole list: */ |
| static void |
| png_free_compression_buffer(png_const_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); |
| } |
| } |
| |
| /* Return the next compression buffer in the list, allocating it if necessary. |
| * The caller must update 'end' if required; this just moves down the list. |
| */ |
| static png_compression_bufferp |
| png_get_compression_buffer(png_const_structrp png_ptr, |
| png_compression_bufferp *end) |
| { |
| png_compression_bufferp next = *end; |
| |
| if (next == NULL) |
| { |
| next = png_voidcast(png_compression_bufferp, png_malloc_base(png_ptr, |
| sizeof *next)); |
| |
| /* Check for OOM: this is a recoverable error for non-critical chunks, let |
| * the caller decide what to do rather than issuing a png_error here. |
| */ |
| if (next != NULL) |
| { |
| next->next = NULL; /* initialize the buffer */ |
| *end = next; |
| } |
| } |
| |
| return next; /* may still be NULL on OOM */ |
| } |
| |
| /* This structure is used to hold all the data for zlib compression of a single |
| * stream of data. It may be re-used, it stores the compressed data internally |
| * and can handle arbitrary input and output. |
| * |
| * 'list' is the output data contained in compression buffers, 'end' points to |
| * list at the start and is advanced down the compression buffer list (extending |
| * it as required) as the data is written. If 'end' points into a compression |
| * buffer (does not point to 'list') that is the buffer in use in |
| * z_stream::{next,avail}_out. |
| * |
| * Compression may be performed in multiple steps, '*end' always points to the |
| * compression buffer *after* the one that is in use, so 'end' is pointing |
| * *into* the one in use. |
| * |
| * end(on entry) .... end ....... end(on exit) |
| * | | | |
| * | | | |
| * V +----V-----+ +-----V----+ +----------+ |
| * list ---> | next --+--> | next --+--> | next | |
| * | output[] | | output[] | | output[] | |
| * +----------+ +----------+ +----------+ |
| * [in use] [unused] |
| * |
| * These invariants should always hold: |
| * |
| * 1) If zs.state is NULL decompression is not in progress, list may be non-NULL |
| * but end could be anything; |
| * |
| * 2) Otherwise if zs.next_out is NULL list will be NULL and end will point at |
| * list, len, overflow and start will be 0; |
| * |
| * 3) Otherwise list is non-NULL and end points at the 'next' element of an |
| * in-use compression buffer. zs.next_out points into the 'output' element |
| * of the same buffer. {overflow, len} is the amount of compressed data, len |
| * being the low 31 bits, overflow being the higher bits. start is used for |
| * writing and is the index of the first byte in list->output to write, |
| * {overflow, len} does not include start. |
| */ |
| typedef struct |
| { |
| z_stream zs; /* zlib compression data */ |
| png_compression_bufferp list; /* Head of the buffer list */ |
| png_compression_bufferp *end; /* Pointer to last 'next' pointer */ |
| png_uint_32 len; /* Bottom 31 bits of data length */ |
| unsigned int overflow; /* Top bits of data length */ |
| unsigned int start; /* Start of data in first block */ |
| } png_zlib_compress, *png_zlib_compressp; |
| |
| /* png_zlib_compress methods */ |
| /* Initialize the compress structure. The z_stream itself is not initialized, |
| * however the the 'user' fields are set, including {next,avail}_{in,out}. The |
| * initialization does not change 'list', however it does set 'end' to point to |
| * it, effectively truncating the list. |
| */ |
| static void |
| png_zlib_compress_init(png_structrp png_ptr, png_zlib_compressp pz) |
| { |
| /* png_zlib_compress z_stream: */ |
| pz->zs.zalloc = png_zalloc; |
| pz->zs.zfree = png_zfree; |
| /* NOTE: this does not destroy 'restrict' because in all the functions herein |
| * *png_ptr is only ever accessed via *either* pz->zs.opaque *or* a passed in |
| * png_ptr. |
| */ |
| pz->zs.opaque = png_ptr; |
| |
| pz->zs.next_in = NULL; |
| pz->zs.avail_in = 0U; |
| pz->zs.total_in = 0U; |
| |
| pz->zs.next_out = NULL; |
| pz->zs.avail_out = 0U; |
| pz->zs.total_out = 0U; |
| |
| pz->zs.msg = PNGZ_MSG_CAST("zlib success"); /* safety */ |
| |
| /* pz->list preserved */ |
| pz->end = &pz->list; |
| pz->len = 0U; |
| pz->overflow = 0U; |
| pz->start = 0U; |
| } |
| |
| /* Return the png_ptr: this is defined here for all the remaining |
| * png_zlib_compress methods because they are only ever called with zs |
| * initialized. |
| */ |
| #define png_ptr png_voidcast(png_const_structrp, pz->zs.opaque) |
| |
| #if PNG_RELEASE_BUILD |
| # define png_zlib_compress_validate(pz, in_use) ((void)0) |
| #else /* !RELEASE_BUILD */ |
| static void |
| png_zlib_compress_validate(png_zlib_compressp pz, int in_use) |
| { |
| const uInt o_size = sizeof pz->list->output; |
| |
| affirm(pz->end != NULL && (in_use || (pz->zs.next_in == NULL && |
| pz->zs.avail_in == 0U && *pz->end == NULL))); |
| |
| if (pz->overflow == 0U && pz->len == 0U && pz->start == 0U) /* empty */ |
| { |
| affirm((pz->end == &pz->list && pz->zs.next_out == NULL |
| && pz->zs.avail_out == 0U) || |
| (pz->list != NULL && pz->end == &pz->list->next && |
| pz->zs.next_out == pz->list->output && |
| pz->zs.avail_out == o_size)); |
| } |
| |
| else /* not empty */ |
| { |
| png_compression_bufferp *ep = &pz->list, list; |
| png_uint_32 o, l; |
| |
| affirm(*ep != NULL && pz->zs.next_out != NULL); |
| |
| /* Check the list length: */ |
| o = pz->overflow; |
| l = pz->len; |
| affirm((l & 0x80000000U) == 0U && (o & 0x80000000U) == 0U); |
| |
| do |
| { |
| list = *ep; |
| l -= o_size; |
| if (l & 0x80000000U) --o, l &= 0x7FFFFFFFU; |
| ep = &list->next; |
| } |
| while (ep != pz->end); |
| |
| l += pz->start; |
| l += pz->zs.avail_out; |
| if (l & 0x80000000U) ++o, l &= 0x7FFFFFFFU; |
| |
| affirm(o == 0U && l == 0U && pz->zs.next_out >= list->output && |
| pz->zs.next_out + pz->zs.avail_out == list->output + o_size); |
| } |
| } |
| #endif /* !RELEASE_BUILD */ |
| |
| /* Destroy one zlib compress structure. */ |
| static void |
| png_zlib_compress_destroy(png_zlib_compressp pz, int check) |
| { |
| /* If the 'opaque' pointer is NULL this png_zlib_compress was never |
| * initialized, so do nothing. |
| */ |
| if (png_ptr != NULL) |
| { |
| if (pz->zs.state != NULL) |
| { |
| if (check) |
| png_zlib_compress_validate(pz, 0/*in_use*/); |
| |
| png_deflateEnd(png_ptr, &pz->zs, check); |
| } |
| |
| pz->end = &pz->list; /* safety */ |
| png_free_compression_buffer(png_ptr, &pz->list); |
| } |
| } |
| |
| /* Ensure that space is available for output, returns the amount of space |
| * available, 0 on OOM. This updates pz->zs.avail_out (etc) as required. |
| */ |
| static uInt |
| png_zlib_compress_avail_out(png_zlib_compressp pz) |
| { |
| uInt avail_out = pz->zs.avail_out; |
| |
| png_zlib_compress_validate(pz, 1/*in_use*/); |
| |
| if (avail_out == 0U) |
| { |
| png_compression_bufferp next; |
| |
| affirm(pz->end == &pz->list || (pz->end != NULL && pz->list != NULL)); |
| next = png_get_compression_buffer(png_ptr, pz->end); |
| |
| if (next != NULL) |
| { |
| pz->zs.next_out = next->output; |
| pz->zs.avail_out = avail_out = sizeof next->output; |
| pz->end = &next->next; |
| } |
| |
| /* else return 0: OOM */ |
| } |
| |
| else |
| affirm(pz->end != NULL && pz->list != NULL); |
| |
| return avail_out; |
| } |
| |
| /* Compress the given data given an initialized png_zlib_compress structure. |
| * This may be called multiple times, interleaved with writes as required. |
| * |
| * The input data is passed in in pz->zs.next_in, however the length of the data |
| * is in 'input_len' (to avoid the zlib uInt limit) and pz->zs.avail_in is |
| * overwritten (and left at 0). |
| * |
| * The output information is used and the amount of compressed data is added on |
| * to pz->{overflow,len}. |
| * |
| * If 'limit' is a limit on the amount of data to add to the output (not the |
| * total amount). The function will retun Z_BUF_ERROR if the limit is reached |
| * and the function will never produce more (additional) compressed data than |
| * the limit. |
| * |
| * All of zstream::next_in[input] is consumed if a success code is returned |
| * (Z_OK or Z_STREAM_END if flush is Z_FINISH), otherwise next_in may be used to |
| * determine how much was compressed. |
| * |
| * pz->overflow is not checked for overflow, so if 'limit' is not set overflow |
| * is possible. The caller must guard against this when supplying a limit of 0. |
| */ |
| static int |
| png_compress( |
| png_zlib_compressp pz, |
| png_alloc_size_t input_len, /* Length of data to be compressed */ |
| png_uint_32 limit, /* Limit on amount of compressed data made */ |
| int flush) /* Flush parameter at end of input */ |
| { |
| const int unlimited = (limit == 0U); |
| |
| /* Sanity checking: */ |
| affirm(pz->zs.state != NULL && |
| (pz->zs.next_out == NULL |
| ? pz->end == &pz->list && pz->len == 0U && pz->overflow == 0U |
| : pz->list != NULL && pz->end != NULL)); |
| implies(pz->zs.next_out == NULL, pz->zs.avail_out == 0); |
| |
| for (;;) |
| { |
| uInt extra; |
| |
| /* OUTPUT: make sure some space is available: */ |
| if (png_zlib_compress_avail_out(pz) == 0U) |
| return Z_MEM_ERROR; |
| |
| /* INPUT: limit the deflate call input to ZLIB_IO_MAX: */ |
| /* Adjust the input counters: */ |
| { |
| uInt avail_in = ZLIB_IO_MAX; |
| |
| if (avail_in > input_len) |
| avail_in = (uInt)/*SAFE*/input_len; |
| |
| input_len -= avail_in; |
| pz->zs.avail_in = avail_in; |
| } |
| |
| if (!unlimited && pz->zs.avail_out > limit) |
| { |
| extra = (uInt)/*SAFE*/(pz->zs.avail_out - limit); /* unused bytes */ |
| pz->zs.avail_out = (uInt)/*SAFE*/limit; |
| limit = 0U; |
| } |
| |
| else |
| { |
| extra = 0U; |
| limit -= pz->zs.avail_out; /* limit >= 0U */ |
| } |
| |
| pz->len += pz->zs.avail_out; /* maximum that can be produced */ |
| |
| /* Compress the data */ |
| { |
| int ret = deflate(&pz->zs, input_len > 0U ? Z_NO_FLUSH : flush); |
| |
| /* Claw back input data that was not consumed (because avail_in is |
| * reset above every time round the loop) and correct the output |
| * length. |
| */ |
| input_len += pz->zs.avail_in; |
| pz->zs.avail_in = 0; /* safety */ |
| pz->len -= pz->zs.avail_out; |
| |
| if (pz->len & 0x80000000U) |
| ++pz->overflow, pz->len &= 0x7FFFFFFFU; |
| |
| limit += pz->zs.avail_out; |
| pz->zs.avail_out += extra; |
| |
| /* Check the error code: */ |
| switch (ret) |
| { |
| case Z_OK: |
| if (pz->zs.avail_out > extra) |
| { |
| /* zlib had output space, so all the input should have been |
| * consumed: |
| */ |
| affirm(input_len == 0U /* else unexpected stop */ && |
| flush != Z_FINISH/* ret != Z_STREAM_END */); |
| return Z_OK; |
| } |
| |
| else |
| { |
| /* zlib ran out of output space, produce some more. If the |
| * limit is 0 at this point, however, no more space is |
| * available. |
| */ |
| if (unlimited || limit > 0U) |
| break; /* Allocate more output */ |
| |
| /* No more output space available, but the input may have all |
| * been consumed. |
| */ |
| if (input_len == 0U && flush != Z_FINISH) |
| return Z_OK; |
| |
| /* Input all consumed, but insufficient space to flush the |
| * output; this is the Z_BUF_ERROR case. |
| */ |
| return Z_BUF_ERROR; |
| } |
| |
| case Z_STREAM_END: |
| affirm(input_len == 0U && flush == Z_FINISH); |
| return Z_STREAM_END; |
| |
| case Z_BUF_ERROR: |
| /* This means that we are flushing all the output; expect |
| * avail_out and input_len to be 0. |
| */ |
| affirm(input_len == 0U && pz->zs.avail_out == extra); |
| /* Allocate another buffer */ |
| break; |
| |
| default: |
| /* An error */ |
| return ret; |
| } |
| } |
| } |
| } |
| |
| #undef png_ptr /* remove definition using a png_zlib_compressp */ |
| |
| /* All the compression state is held here, it is allocated when required. This |
| * ensures that the read code doesn't carry the overhead of the much less |
| * frequently used write stuff. |
| * |
| * TODO: make png_create_write_struct allocate this stuff after the main |
| * png_struct. |
| */ |
| typedef struct png_zlib_state |
| { |
| png_zlib_compress s; /* Primary compression state */ |
| |
| # ifdef PNG_SELECT_FILTER_METHODICALLY_SUPPORTED |
| /* The 'methodical' method uses up to PNG_FILTER_VALUE_LAST of these to |
| * test each possible filter: |
| */ |
| png_zlib_compress filter[PNG_FILTER_VALUE_LAST]; |
| # endif /* SELECT_FILTER_METHODICALLY */ |
| |
| png_compression_bufferp stash; /* Unused compression buffers */ |
| |
| # ifdef PNG_WRITE_FLUSH_SUPPORTED |
| png_uint_32 flush_dist; /* how many rows apart to flush, 0 - no flush */ |
| png_uint_32 flush_rows; /* number of rows written since last flush */ |
| # endif /* WRITE_FLUSH */ |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| unsigned int filter_mask :8; /* mask of filters to consider on write */ |
| unsigned int filters :8; /* Filters for current row */ |
| unsigned int filter_oom :1; /* ran out of memory */ |
| #endif /* WRITE_FILTER */ |
| |
| /* Zlib parameters to be used for IDAT and (possibly) text/ICC profile |
| * compression. |
| */ |
| int zlib_level; /* holds zlib compression level */ |
| int zlib_method; /* holds zlib compression method */ |
| int zlib_window_bits; /* holds zlib compression window bits */ |
| int zlib_mem_level; /* holds zlib compression memory level */ |
| int zlib_strategy; /* holds zlib compression strategy */ |
| |
| /* The same, but these are the values actually set into the z_stream: */ |
| int zlib_set_level; |
| int zlib_set_method; |
| int zlib_set_window_bits; |
| int zlib_set_mem_level; |
| int zlib_set_strategy; |
| |
| # ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED |
| int zlib_text_level; /* holds zlib compression level */ |
| int zlib_text_method; /* holds zlib compression method */ |
| int zlib_text_window_bits; /* holds zlib compression window bits */ |
| int zlib_text_mem_level; /* holds zlib compression memory level */ |
| int zlib_text_strategy; /* holds zlib compression strategy */ |
| # endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ |
| } png_zlib_state; |
| |
| /* This returns the zlib compression state and has the side effect of |
| * initializing it if it does not exist. |
| */ |
| static png_zlib_statep |
| png_get_zlib_state(png_structrp png_ptr) |
| { |
| if (png_ptr != NULL) |
| { |
| png_zlib_state *ps = png_ptr->zlib_state; |
| |
| if (ps == NULL && !png_ptr->read_struct) |
| { |
| png_ptr->zlib_state = ps = png_voidcast(png_zlib_state*, |
| png_malloc(png_ptr, sizeof *ps)); |
| |
| /* Clear to NULL/0: */ |
| memset(ps, 0, sizeof *ps); |
| |
| png_zlib_compress_init(png_ptr, &ps->s); |
| |
| # ifdef PNG_SELECT_FILTER_METHODICALLY_SUPPORTED |
| { |
| unsigned int i; |
| |
| for (i=0; i<PNG_FILTER_VALUE_LAST; ++i) |
| ps->filter[i].zs.opaque = NULL; |
| } |
| # endif /* SELECT_FILTER_METHODICALLY */ |
| |
| ps->stash = NULL; |
| |
| # ifdef PNG_WRITE_FLUSH_SUPPORTED |
| /* Set this to prevent flushing by making it larger than the number |
| * of rows in the largest interlaced PNG; PNG_UINT_31_MAX times |
| * (1/8+1/8+1/8+1/4+1/4+1/2+1/2); 1.875, or 15/8 |
| */ |
| ps->flush_dist = 0xEFFFFFFFU; |
| ps->flush_rows = 0U; |
| # endif /* WRITE_FLUSH */ |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| ps->filter_mask = PNG_NO_FILTERS; /* unset */ |
| ps->filters = 0U; |
| ps->filter_oom = 0U; |
| # endif /* WRITE_FILTER */ |
| |
| /* Zlib parameters to be used for IDAT and (possibly) text/ICC profile |
| * compression. |
| */ |
| ps->zlib_level = PNG_Z_DEFAULT_COMPRESSION; |
| ps->zlib_method = Z_DEFLATED; |
| ps->zlib_window_bits = 15; /* 8..15 permitted, 15 is the default */ |
| ps->zlib_mem_level = 8; /* 1..9 permitted, 8 is the default */ |
| ps->zlib_strategy = -1/*unset (invalid value)*/; |
| |
| # ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED |
| ps->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION; |
| ps->zlib_text_method = Z_DEFLATED; |
| ps->zlib_text_window_bits = 15; |
| ps->zlib_text_mem_level = 8; |
| ps->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY; |
| # endif /* WRITE_COMPRESSED_TEXT */ |
| } |
| |
| return ps; |
| } |
| |
| return NULL; |
| } |
| |
| /* Internal API to clean up all the deflate related stuff, including the buffer |
| * lists. |
| */ |
| static void /* PRIVATE */ |
| png_deflate_release(png_structrp png_ptr, png_zlib_statep ps, int check) |
| { |
| /* This must happen before ps->s is destroyed below because the structures |
| * may be shared: |
| */ |
| # ifdef PNG_SELECT_FILTER_METHODICALLY_SUPPORTED |
| unsigned int i; |
| |
| /* Note that png_zlib_compress_destroy checks the 'opaque' pointer and |
| * does nothing if it is NULL. |
| */ |
| for (i=0U; i<PNG_FILTER_VALUE_LAST; ++i) |
| if (ps->filter[i].zs.state != ps->s.zs.state) |
| { |
| png_zlib_compress_destroy(&ps->filter[i], 0/*check*/); |
| ps->filter[i].zs.opaque = NULL; |
| } |
| # endif /* SELECT_FILTER_METHODICALLY */ |
| |
| /* The main z_stream opaque pointer needs to remain set to png_ptr; it is |
| * only set once. |
| */ |
| png_zlib_compress_destroy(&ps->s, check); |
| png_free_compression_buffer(png_ptr, &ps->stash); |
| } |
| |
| void /* PRIVATE */ |
| png_deflate_destroy(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| |
| if (ps != NULL) |
| { |
| png_deflate_release(png_ptr, ps, 0/*check*/); |
| png_ptr->zlib_state = NULL; |
| png_free(png_ptr, ps); |
| } |
| } |
| |
| /* Initialize the compressor for the appropriate type of compression. */ |
| static png_zlib_statep |
| png_deflate_claim(png_structrp png_ptr, png_uint_32 owner, |
| png_alloc_size_t data_size) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| affirm(ps != NULL && png_ptr->zowner == 0); |
| |
| { |
| int level = ps->zlib_level; |
| int method = ps->zlib_method; |
| int windowBits = ps->zlib_window_bits; |
| int memLevel = ps->zlib_mem_level; |
| int strategy = ps->zlib_strategy; |
| int ret; /* zlib return code */ |
| |
| if (owner != png_IDAT) |
| { |
| # ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED |
| level = ps->zlib_text_level; |
| method = ps->zlib_text_method; |
| windowBits = ps->zlib_text_window_bits; |
| memLevel = ps->zlib_text_mem_level; |
| strategy = ps->zlib_text_strategy; |
| # else /* !WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ |
| /* 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 /* !WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ |
| } |
| |
| /* 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 <= 16384U) |
| { |
| /* 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 + 262U <= half_window_size) |
| { |
| half_window_size >>= 1; |
| --windowBits; |
| } |
| } |
| |
| /* Check against the previous initialized values, if any. */ |
| if (ps->s.zs.state != NULL && |
| (ps->zlib_set_level != level || |
| ps->zlib_set_method != method || |
| ps->zlib_set_window_bits != windowBits || |
| ps->zlib_set_mem_level != memLevel || |
| ps->zlib_set_strategy != strategy)) |
| png_deflateEnd(png_ptr, &ps->s.zs, 0/*check*/); |
| |
| /* For safety clear out the input and output pointers (currently zlib |
| * doesn't use them on Init, but it might in the future). |
| */ |
| ps->s.zs.next_in = NULL; |
| ps->s.zs.avail_in = 0; |
| ps->s.zs.next_out = NULL; |
| ps->s.zs.avail_out = 0; |
| |
| /* The length fields must be cleared too and the lists reset: */ |
| ps->s.overflow = ps->s.len = ps->s.start = 0U; |
| |
| if (ps->s.list != NULL) /* error in prior chunk writing */ |
| { |
| debug(ps->stash == NULL); |
| ps->stash = ps->s.list; |
| ps->s.list = NULL; |
| } |
| |
| ps->s.end = &ps->s.list; |
| |
| /* Now initialize if required, setting the new parameters, otherwise just |
| * do a simple reset to the previous parameters. |
| */ |
| if (ps->s.zs.state != NULL) |
| ret = deflateReset(&ps->s.zs); |
| |
| else |
| ret = deflateInit2(&ps->s.zs, level, method, windowBits, memLevel, |
| strategy); |
| |
| /* The return code is from either deflateReset or deflateInit2; they have |
| * pretty much the same set of error codes. |
| */ |
| if (ret == Z_OK && ps->s.zs.state != NULL) |
| png_ptr->zowner = owner; |
| |
| else |
| { |
| png_zstream_error(&ps->s.zs, ret); |
| png_error(png_ptr, ps->s.zs.msg); |
| } |
| } |
| |
| return ps; |
| } |
| |
| #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED /* includes iCCP */ |
| /* Compress the block of data at the end of a chunk. This claims and releases |
| * png_struct::z_stream. It returns the amount of data in the chunk list or |
| * zero on error (a zlib stream always contains some bytes!) |
| * |
| * prefix_len is the amount of (uncompressed) data before the start of the |
| * compressed data. The routine will return 0 if the total of the compressed |
| * data and the prefix exceeds PNG_UINT_MAX_31. |
| * |
| * NOTE: this function may not return; it only returns 0 if |
| * png_chunk_report(PNG_CHUNK_WRITE_ERROR) returns (not the default). |
| */ |
| static int /* success */ |
| png_compress_chunk_data(png_structrp png_ptr, png_uint_32 chunk_name, |
| png_uint_32 prefix_len, png_const_voidp input, png_alloc_size_t input_len) |
| { |
| /* 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. |
| */ |
| png_zlib_statep ps = png_deflate_claim(png_ptr, chunk_name, input_len); |
| |
| affirm(ps != NULL); |
| |
| /* The data compression function always returns so that we can clean up. */ |
| ps->s.zs.next_in = PNGZ_INPUT_CAST(png_voidcast(const Bytef*, input)); |
| |
| /* Use the stash, if available: */ |
| debug(ps->s.list == NULL); |
| ps->s.list = ps->stash; |
| ps->stash = NULL; |
| |
| { |
| int ret = png_compress(&ps->s, input_len, PNG_UINT_31_MAX-prefix_len, |
| Z_FINISH); |
| |
| ps->s.zs.next_out = NULL; /* safety */ |
| ps->s.zs.avail_out = 0; |
| ps->s.zs.next_in = NULL; |
| ps->s.zs.avail_in = 0; |
| png_ptr->zowner = 0; /* release png_ptr::zstream */ |
| |
| /* Since Z_FINISH was passed as the flush parameter any result other than |
| * Z_STREAM_END is an error. In any case in the event of an error free |
| * the whole compression state; the only expected error is Z_MEM_ERROR. |
| */ |
| if (ret != Z_STREAM_END) |
| { |
| png_zlib_compress_destroy(&ps->s, 0/*check*/); |
| |
| /* This is not very likely given the PNG_UINT_31_MAX limit above, but |
| * if code is added to limit the size of the chunks produced it can |
| * start to happen. |
| */ |
| if (ret == Z_BUF_ERROR) |
| ps->s.zs.msg = PNGZ_MSG_CAST("compressed chunk too long"); |
| |
| else |
| png_zstream_error(&ps->s.zs, ret); |
| |
| png_chunk_report(png_ptr, ps->s.zs.msg, PNG_CHUNK_WRITE_ERROR); |
| return 0; |
| } |
| } |
| |
| /* png_compress is meant to guarantee this on a successful return: */ |
| affirm(ps->s.overflow == 0U && ps->s.len <= PNG_UINT_31_MAX - prefix_len); |
| |
| # ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
| /* Fix up the deflate header, if required (and possible): */ |
| if (ps->s.len >= 2U) |
| optimize_cmf(png_ptr, ps->s.list->output, input_len); |
| # endif /* WRITE_OPTIMIZE_CMF */ |
| |
| return 1; |
| } |
| |
| /* Return the length of the compressed data; this is effectively a debug |
| * function to catch inconsistencies caused by internal errors. It will |
| * disappear in a release build. |
| */ |
| #if PNG_RELEASE_BUILD |
| # define png_length_compressed_chunk_data(pp, p) ((pp)->zlib_state->s.len) |
| #else /* !RELEASE_BUILD */ |
| static png_uint_32 |
| png_length_compressed_chunk_data(png_structrp png_ptr, png_uint_32 p) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| |
| debug(ps != NULL && ps->s.overflow == 0U && ps->s.len <= PNG_UINT_31_MAX-p); |
| return ps->s.len; |
| } |
| #endif /* !RELEASE_BUILD */ |
| |
| /* Write all the data produced by the above function; the caller must write the |
| * prefix and chunk header. |
| */ |
| static void |
| png_write_compressed_chunk_data(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| png_compression_bufferp next; |
| png_uint_32 output_len; |
| |
| affirm(ps != NULL && ps->s.overflow == 0U); |
| next = ps->s.list; |
| |
| for (output_len = ps->s.len; output_len > 0U; next = next->next) |
| { |
| png_uint_32 size = PNG_ROW_BUFFER_SIZE; |
| |
| /* If this affirm fails there is a bug in the calculation of |
| * output_length above, or in the buffer_limit code in png_compress. |
| */ |
| affirm(next != NULL && output_len > 0U); |
| |
| if (size > output_len) |
| size = output_len; |
| |
| png_write_chunk_data(png_ptr, next->output, size); |
| |
| output_len -= size; |
| } |
| |
| /* Release the list back to the stash. */ |
| debug(ps->stash == NULL); |
| ps->stash = ps->s.list; |
| ps->s.list = NULL; |
| ps->s.end = &ps->s.list; |
| } |
| #endif /* WRITE_COMPRESSED_TEXT */ |
| |
| #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 at least 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 CHUNK_WRITE_ERROR. |
| */ |
| static unsigned int |
| png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key) |
| { |
| png_const_charp orig_key = key; |
| unsigned int 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 == 0) |
| { |
| /* 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 == 0) |
| bad_character = ch; /* just skip it, record the first error */ |
| } |
| |
| if (key_len > 0 && space != 0) /* trailing space */ |
| { |
| --key_len, --new_key; |
| if (bad_character == 0) |
| bad_character = 32; |
| } |
| |
| /* Terminate the keyword */ |
| *new_key = 0; |
| |
| if (key_len == 0) |
| return 0; |
| |
| #ifdef PNG_WARNINGS_SUPPORTED |
| /* Try to only output one warning per keyword: */ |
| if (*key != 0) /* keyword too long */ |
| png_app_warning(png_ptr, "keyword truncated"); |
| |
| else if (bad_character != 0) |
| { |
| 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'"); |
| } |
| #endif /* WARNINGS */ |
| |
| return key_len; |
| } |
| #endif /* WRITE_TEXT || WRITE_pCAL || WRITE_iCCP || WRITE_sPLT */ |
| |
| /* 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_method, |
| 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 |
| 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"); |
| |
| break; |
| |
| case PNG_COLOR_TYPE_PALETTE: |
| switch (bit_depth) |
| { |
| case 1: |
| case 2: |
| case 4: |
| case 8: |
| 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"); |
| |
| 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"); |
| |
| break; |
| |
| default: |
| png_error(png_ptr, "Invalid image color type specified"); |
| } |
| |
| if (compression_type != PNG_COMPRESSION_TYPE_BASE) |
| { |
| png_app_error(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) != 0 && |
| ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && |
| (color_type == PNG_COLOR_TYPE_RGB || |
| color_type == PNG_COLOR_TYPE_RGB_ALPHA) && |
| (filter_method == PNG_INTRAPIXEL_DIFFERENCING)) && |
| # endif /* MNG_FEATURES */ |
| filter_method != PNG_FILTER_TYPE_BASE) |
| { |
| png_app_error(png_ptr, "Invalid filter type specified"); |
| filter_method = PNG_FILTER_TYPE_BASE; |
| } |
| |
| if (interlace_type != PNG_INTERLACE_NONE && |
| interlace_type != PNG_INTERLACE_ADAM7) |
| { |
| png_app_error(png_ptr, "Invalid interlace type specified"); |
| interlace_type = PNG_INTERLACE_ADAM7; |
| } |
| |
| /* Save the relevant information */ |
| png_ptr->bit_depth = png_check_byte(png_ptr, bit_depth); |
| png_ptr->color_type = png_check_byte(png_ptr, color_type); |
| png_ptr->interlaced = png_check_byte(png_ptr, interlace_type); |
| png_ptr->filter_method = png_check_byte(png_ptr, filter_method); |
| png_ptr->compression_type = png_check_byte(png_ptr, compression_type); |
| png_ptr->width = width; |
| png_ptr->height = height; |
| |
| /* Pack the header information into the buffer */ |
| png_save_uint_32(buf, width); |
| png_save_uint_32(buf + 4, height); |
| buf[8] = png_check_byte(png_ptr, bit_depth); |
| buf[9] = png_check_byte(png_ptr, color_type); |
| buf[10] = png_check_byte(png_ptr, compression_type); |
| buf[11] = png_check_byte(png_ptr, filter_method); |
| buf[12] = png_check_byte(png_ptr, interlace_type); |
| |
| /* Write the chunk */ |
| png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13); |
| 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_structrp png_ptr, png_const_colorp palette, |
| unsigned int num_pal) |
| { |
| png_uint_32 max_palette_length, i; |
| png_const_colorp pal_ptr; |
| png_byte buf[3]; |
| |
| png_debug(1, "in png_write_PLTE"); |
| |
| max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ? |
| (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH; |
| |
| if (( |
| # ifdef PNG_MNG_FEATURES_SUPPORTED |
| (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 && |
| # endif /* MNG_FEATURES */ |
| num_pal == 0) || num_pal > max_palette_length) |
| { |
| 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) == 0) |
| { |
| png_warning(png_ptr, |
| "Ignoring request to write a PLTE chunk in grayscale PNG"); |
| |
| return; |
| } |
| |
| png_ptr->num_palette = png_check_bits(png_ptr, num_pal, 9); |
| png_debug1(3, "num_palette = %d", png_ptr->num_palette); |
| |
| png_write_chunk_header(png_ptr, png_PLTE, num_pal * 3U); |
| |
| 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, 3U); |
| } |
| |
| png_write_chunk_end(png_ptr); |
| png_ptr->mode |= PNG_HAVE_PLTE; |
| } |
| |
| /* 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; |
| } |
| |
| #if defined(PNG_WRITE_gAMA_SUPPORTED) || defined(PNG_WRITE_cHRM_SUPPORTED) |
| static int |
| png_save_int_31(png_structrp png_ptr, png_bytep buf, png_int_32 i) |
| /* Save a signed value as a PNG unsigned value; the argument is required to |
| * be in the range 0..0x7FFFFFFFU. If not a *warning* is produced and false |
| * is returned. Because this is only called from png_write_cHRM_fixed and |
| * png_write_gAMA_fixed below this is safe (we don't need either chunk, |
| * particularly if the value is bogus.) |
| * |
| * The warning is png_app_error; it may return if the app tells it to but the |
| * app can have it error out. JB 20150821: I believe the checking in png.c |
| * actually makes this error impossible, but this is safe. |
| */ |
| { |
| #ifndef __COVERITY__ |
| if (i >= 0 && i <= 0x7FFFFFFF) |
| #else |
| /* Supress bogus Coverity complaint */ |
| if (i >= 0) |
| #endif |
| { |
| png_save_uint_32(buf, (png_uint_32)/*SAFE*/i); |
| return 1; |
| } |
| |
| else |
| { |
| png_chunk_report(png_ptr, "negative value in cHRM or gAMA", |
| PNG_CHUNK_WRITE_ERROR); |
| return 0; |
| } |
| } |
| #endif /* WRITE_gAMA || WRITE_cHRM */ |
| |
| #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 */ |
| if (png_save_int_31(png_ptr, buf, 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_chunk_report(png_ptr, "Invalid sRGB rendering intent specified", |
| PNG_CHUNK_WRITE_ERROR); |
| |
| buf[0] = png_check_byte(png_ptr, 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_voidp profile) |
| { |
| png_uint_32 name_len; |
| png_uint_32 profile_len; |
| png_byte new_name[81]; /* 1 byte for the compression byte */ |
| |
| png_debug(1, "in png_write_iCCP"); |
| |
| affirm(profile != NULL); |
| |
| profile_len = png_get_uint_32(profile); |
| name_len = png_check_keyword(png_ptr, name, new_name); |
| |
| if (name_len == 0) |
| { |
| png_chunk_report(png_ptr, "iCCP: invalid keyword", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| ++name_len; /* trailing '\0' */ |
| new_name[name_len++] = PNG_COMPRESSION_TYPE_BASE; |
| |
| if (png_compress_chunk_data(png_ptr, png_iCCP, name_len, profile, |
| profile_len)) |
| { |
| png_write_chunk_header(png_ptr, png_iCCP, |
| name_len+png_length_compressed_chunk_data(png_ptr, name_len)); |
| png_write_chunk_data(png_ptr, new_name, name_len); |
| png_write_compressed_chunk_data(png_ptr); |
| 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; |
| |
| 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, new_name, name_len + 1); |
| |
| png_write_chunk_data(png_ptr, &spalette->depth, 1); |
| |
| /* Loop through each palette entry, writing appropriately */ |
| for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++) |
| { |
| if (spalette->depth == 8) |
| { |
| entrybuf[0] = png_check_byte(png_ptr, ep->red); |
| entrybuf[1] = png_check_byte(png_ptr, ep->green); |
| entrybuf[2] = png_check_byte(png_ptr, ep->blue); |
| entrybuf[3] = png_check_byte(png_ptr, 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); |
| } |
| |
| 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) != 0) |
| { |
| unsigned int maxbits; |
| |
| maxbits = color_type==PNG_COLOR_TYPE_PALETTE ? 8 : png_ptr->bit_depth; |
| |
| if (sbit->red == 0 || sbit->red > maxbits || |
| sbit->green == 0 || sbit->green > maxbits || |
| sbit->blue == 0 || sbit->blue > maxbits) |
| { |
| png_app_error(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->bit_depth) |
| { |
| png_app_error(png_ptr, "Invalid sBIT depth specified"); |
| return; |
| } |
| |
| buf[0] = sbit->gray; |
| size = 1; |
| } |
| |
| if ((color_type & PNG_COLOR_MASK_ALPHA) != 0) |
| { |
| if (sbit->alpha == 0 || sbit->alpha > png_ptr->bit_depth) |
| { |
| png_app_error(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 */ |
| if (png_save_int_31(png_ptr, buf, xy->whitex) && |
| png_save_int_31(png_ptr, buf + 4, xy->whitey) && |
| png_save_int_31(png_ptr, buf + 8, xy->redx) && |
| png_save_int_31(png_ptr, buf + 12, xy->redy) && |
| png_save_int_31(png_ptr, buf + 16, xy->greenx) && |
| png_save_int_31(png_ptr, buf + 20, xy->greeny) && |
| png_save_int_31(png_ptr, buf + 24, xy->bluex) && |
| png_save_int_31(png_ptr, 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) |
| { |
| affirm(num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH); |
| { |
| # ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED |
| union |
| { |
| png_uint_32 u32[1]; |
| png_byte b8[PNG_MAX_PALETTE_LENGTH]; |
| } inverted_alpha; |
| |
| /* Invert the alpha channel (in tRNS) if required */ |
| if (png_ptr->write_invert_alpha) |
| { |
| int i; |
| |
| memcpy(inverted_alpha.b8, trans_alpha, num_trans); |
| |
| for (i=0; 4*i<num_trans; ++i) |
| inverted_alpha.u32[i] = ~inverted_alpha.u32[i]; |
| |
| trans_alpha = inverted_alpha.b8; |
| } |
| # endif /* WRITE_INVERT_ALPHA */ |
| |
| png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, num_trans); |
| } |
| } |
| |
| else if (color_type == PNG_COLOR_TYPE_GRAY) |
| { |
| /* One 16 bit value */ |
| affirm(tran->gray < (1 << png_ptr->bit_depth)); |
| 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); |
| affirm(png_ptr->bit_depth == 8 || (buf[0] | buf[2] | buf[4]) == 0); |
| png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6); |
| } |
| |
| else /* Already checked in png_set_tRNS */ |
| impossible("invalid tRNS"); |
| } |
| #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 != 0 || |
| (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) && |
| # endif /* MNG_FEATURES */ |
| back->index >= png_ptr->num_palette) |
| { |
| png_app_error(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) != 0) |
| { |
| 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]) != 0) |
| #else |
| if ((buf[0] | buf[2] | buf[4]) != 0) |
| #endif |
| { |
| png_app_error(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_app_error(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) |
| { |
| unsigned int 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_chunk_report(png_ptr, "tEXt: invalid keyword", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| if (text == NULL || *text == '\0') |
| text_len = 0; |
| |
| else |
| text_len = strlen(text); |
| |
| if (text_len > PNG_UINT_31_MAX - (key_len+1)) |
| { |
| png_chunk_report(png_ptr, "tEXt: text too long", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| /* 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 != 0) |
| 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, |
| int compression) |
| { |
| unsigned int key_len; |
| png_byte new_key[81]; |
| |
| png_debug(1, "in png_write_zTXt"); |
| |
| if (compression != PNG_TEXT_COMPRESSION_zTXt) |
| png_app_warning(png_ptr, "zTXt: invalid compression type ignored"); |
| |
| key_len = png_check_keyword(png_ptr, key, new_key); |
| |
| if (key_len == 0) |
| { |
| png_chunk_report(png_ptr, "zTXt: invalid keyword", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| /* Add the compression method and 1 for the keyword separator. */ |
| ++key_len; |
| new_key[key_len++] = PNG_COMPRESSION_TYPE_BASE; |
| |
| if (png_compress_chunk_data(png_ptr, png_zTXt, key_len, text, strlen(text))) |
| { |
| png_write_chunk_header(png_ptr, png_zTXt, |
| key_len+png_length_compressed_chunk_data(png_ptr, key_len)); |
| png_write_chunk_data(png_ptr, new_key, key_len); |
| png_write_compressed_chunk_data(png_ptr); |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* else chunk report already issued and ignored */ |
| } |
| #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, data_len; |
| png_size_t lang_len, lang_key_len, text_len; |
| png_byte new_key[82]; /* 80 bytes for the key, 2 byte compression info */ |
| |
| png_debug(1, "in png_write_iTXt"); |
| |
| key_len = png_check_keyword(png_ptr, key, new_key); |
| |
| if (key_len == 0) |
| { |
| png_chunk_report(png_ptr, "iTXt: invalid keyword", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| debug(new_key[key_len] == 0); |
| ++key_len; /* terminating 0 added by png_check_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_chunk_report(png_ptr, "iTXt: invalid compression", |
| PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| new_key[key_len++] = PNG_COMPRESSION_TYPE_BASE; |
| |
| /* 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 (yes, this is really weird |
| * in an 'international' text string. ISO PNG, however, specifies that the |
| * text is UTF-8 and this *IS NOT YET CHECKED*, so invalid sequences may be |
| * present. |
| * |
| * 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)+1U; |
| if (lang_key == NULL) lang_key = ""; /* may be empty */ |
| lang_key_len = strlen(lang_key)+1U; |
| if (text == NULL) text = ""; /* may be empty */ |
| |
| if (lang_len > PNG_UINT_31_MAX-key_len || |
| lang_key_len > PNG_UINT_31_MAX-key_len-lang_len) |
| { |
| png_chunk_report(png_ptr, "iTXt: prefix too long", PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| prefix_len = (png_uint_32)/*SAFE*/(key_len+lang_len+lang_key_len); |
| text_len = strlen(text); /* no trailing '\0' */ |
| |
| if (compression != 0) |
| { |
| if (png_compress_chunk_data(png_ptr, png_iTXt, prefix_len, text, |
| text_len)) |
| data_len = png_length_compressed_chunk_data(png_ptr, prefix_len); |
| |
| else |
| return; /* chunk report already issued and ignored */ |
| } |
| |
| else |
| { |
| if (text_len > PNG_UINT_31_MAX-prefix_len) |
| { |
| png_chunk_report(png_ptr, "iTXt: text too long", |
| PNG_CHUNK_WRITE_ERROR); |
| return; |
| } |
| |
| data_len = (png_uint_32)/*SAFE*/text_len; |
| } |
| |
| png_write_chunk_header(png_ptr, png_iTXt, prefix_len+data_len); |
| png_write_chunk_data(png_ptr, new_key, key_len); |
| png_write_chunk_data(png_ptr, lang, lang_len); |
| png_write_chunk_data(png_ptr, lang_key, lang_key_len); |
| |
| if (compression != 0) |
| png_write_compressed_chunk_data(png_ptr); |
| |
| else |
| png_write_chunk_data(png_ptr, text, data_len); |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif /* WRITE_iTXt */ |
| |
| #if defined(PNG_WRITE_oFFs_SUPPORTED) ||\ |
| defined(PNG_WRITE_pCAL_SUPPORTED) |
| /* PNG signed integers are saved in 32-bit 2's complement format. ANSI C-90 |
| * defines a cast of a signed integer to an unsigned integer either to preserve |
| * the value, if it is positive, or to calculate: |
| * |
| * (UNSIGNED_MAX+1) + integer |
| * |
| * Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the |
| * negative integral value is added the result will be an unsigned value |
| * correspnding to the 2's complement representation. |
| */ |
| static int |
| save_int_32(png_structrp png_ptr, png_bytep buf, png_int_32 j) |
| { |
| png_uint_32 i = 0xFFFFFFFFU & (png_uint_32)/*SAFE & CORRECT*/j; |
| |
| if (i != 0x80000000U/*value not permitted*/) |
| { |
| png_save_uint_32(buf, i); |
| return 1; |
| } |
| |
| else |
| { |
| png_chunk_report(png_ptr, "invalid value in oFFS or pCAL", |
| PNG_CHUNK_WRITE_ERROR); |
| return 0; |
| } |
| } |
| #endif /* WRITE_oFFs || WRITE_pCAL */ |
| |
| #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"); |
| |
| if (save_int_32(png_ptr, buf, x_offset) && |
| save_int_32(png_ptr, buf + 4, y_offset)) |
| { |
| /* unit type is 0 or 1, this has been checked already so the following |
| * is safe: |
| */ |
| buf[8] = unit_type != 0; |
| png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9); |
| } |
| } |
| #endif /* WRITE_oFFs */ |
| |
| #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; |
| size_t units_len; |
| png_byte buf[10]; |
| png_byte new_purpose[80]; |
| |
| 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); |
| |
| if (save_int_32(png_ptr, buf, X0) && |
| save_int_32(png_ptr, buf + 4, X1)) |
| { |
| png_size_tp params_len = png_voidcast(png_size_tp, |
| png_malloc(png_ptr, nparams * sizeof (png_size_t))); |
| int i; |
| size_t total_len = purpose_len + units_len + 10; |
| |
| /* 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); |
| buf[8] = png_check_byte(png_ptr, type); |
| buf[9] = png_check_byte(png_ptr, 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 /* WRITE_pCAL */ |
| |
| #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_check_byte(png_ptr, 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_check_byte(png_ptr, 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 |
| |
| /* These two #defines simplify writing code that depends on one or the other of |
| * the options being both supported and on: |
| */ |
| #ifdef PNG_SELECT_FILTER_METHODICALLY_SUPPORTED |
| # define methodical_option\ |
| ((png_ptr->options >> PNG_SELECT_FILTER_METHODICALLY) & 3U) |
| #else |
| # define methodical_option PNG_OPTION_OFF |
| #endif |
| |
| #ifdef PNG_SELECT_FILTER_HEURISTICALLY_SUPPORTED |
| # define heuristic_option\ |
| ((png_ptr->options >> PNG_SELECT_FILTER_HEURISTICALLY) & 3U) |
| #else /* !SELECT_FILTER_HEURISTICALLY */ |
| # define heuristic_option PNG_OPTION_OFF |
| #endif /* !SELECT_FILTER_HEURISTICALLY */ |
| |
| /* Handle the writing of IDAT chunks from the png_zlib_state in |
| * png_ptr->zlib_state. |
| */ |
| static void |
| png_start_IDAT(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* Default both filter_mask and zlib_strategy here, now that png_ptr has |
| * all the IHDR fields set. |
| */ |
| if (ps && ps->filter_mask == PNG_NO_FILTERS/*unset*/) |
| { |
| /* If there is no filter selection algorithm enabled then the only |
| * option is PNG_FILTER_NONE. |
| */ |
| if (methodical_option == PNG_OPTION_OFF && |
| heuristic_option == PNG_OPTION_OFF) |
| ps->filter_mask = PNG_FILTER_NONE; |
| |
| else |
| ps->filter_mask = PNG_ALL_FILTERS; |
| } |
| # endif /* WRITE_FILTER */ |
| |
| if (ps && ps->zlib_strategy == (-1)/*unset*/) |
| { |
| # ifdef PNG_WRITE_FILTER_SUPPORTED |
| if (ps->filter_mask != PNG_FILTER_NONE) |
| ps->zlib_strategy = PNG_Z_DEFAULT_STRATEGY; |
| else |
| # endif /* WRITE_FILTER */ |
| |
| /* The default with no filters: */ |
| ps->zlib_strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY; |
| } |
| |
| /* This always succeeds or does a png_error: */ |
| png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)); |
| } |
| |
| static void |
| png_end_IDAT(png_structrp png_ptr) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| |
| png_ptr->zowner = 0U; /* release the stream */ |
| |
| if (ps != NULL) |
| png_deflate_release(png_ptr, ps, 1/*check*/); |
| } |
| |
| static void |
| png_write_IDAT(png_structrp png_ptr, int flush) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| |
| /* Check for a correctly initialized list, the requirement that the end |
| * pointer is NULL means that the end of the list can be easily detected. |
| */ |
| affirm(ps != NULL && ps->s.end != NULL && *ps->s.end == NULL); |
| png_zlib_compress_validate(&png_ptr->zlib_state->s, 0/*in_use*/); |
| |
| /* Write IDAT chunks while either 'flush' is true or there are at |
| * least png_ptr->IDAT_size bytes available to be written. |
| */ |
| for (;;) |
| { |
| png_uint_32 len = png_ptr->IDAT_size; |
| |
| if (ps->s.overflow == 0U) |
| { |
| png_uint_32 avail = ps->s.len; |
| |
| if (avail < len) |
| { |
| /* When end_of_image is true everything gets written, otherwise |
| * there must be at least IDAT_size bytes available. |
| */ |
| if (!flush) |
| return; |
| |
| if (avail == 0U) |
| break; |
| |
| len = avail; |
| } |
| } |
| |
| png_write_chunk_header(png_ptr, png_IDAT, len); |
| |
| /* Write bytes from the buffer list, adjusting {overflow,len} as they are |
| * written. |
| */ |
| do |
| { |
| png_compression_bufferp next = ps->s.list; |
| unsigned int avail = sizeof next->output; |
| unsigned int start = ps->s.start; |
| unsigned int written; |
| |
| affirm(next != NULL); |
| |
| if (next->next == NULL) /* end of list */ |
| { |
| /* The z_stream should always be pointing into this output buffer, |
| * the buffer may not be full: |
| */ |
| debug(ps->s.zs.next_out + ps->s.zs.avail_out == |
| next->output + sizeof next->output); |
| avail -= ps->s.zs.avail_out; |
| } |
| |
| else /* not end of list */ |
| debug((ps->s.zs.next_out < next->output || |
| ps->s.zs.next_out > next->output + sizeof next->output) && |
| (ps->s.overflow > 0 || |
| ps->s.start + ps->s.len >= sizeof next->output)); |
| |
| /* First, if this is the very first IDAT (PNG_HAVE_IDAT not set) |
| * optimize the CINFO field: |
| */ |
| # ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
| if ((png_ptr->mode & PNG_HAVE_IDAT) == 0U && |
| avail >= start+2U /* enough for the zlib header */) |
| { |
| debug(start == 0U); |
| optimize_cmf(png_ptr, next->output+start, |
| png_image_size(png_ptr)); |
| } |
| |
| else /* always expect to see at least 2 bytes: */ |
| debug((png_ptr->mode & PNG_HAVE_IDAT) != 0U); |
| # endif /* WRITE_OPTIMIZE_CMF */ |
| |
| /* Set this now to prevent the above happening again second time round |
| * the loop: |
| */ |
| png_ptr->mode |= PNG_HAVE_IDAT; |
| |
| if (avail <= start+len) |
| { |
| /* Write all of this buffer: */ |
| affirm(avail > start); /* else overflow on the subtract */ |
| written = avail-start; |
| png_write_chunk_data(png_ptr, next->output+start, written); |
| |
| /* At the end there are no buffers in the list but the z_stream |
| * still points into the old (just released) buffer. This can |
| * happen when the old buffer is not full if the compressed bytes |
| * exactly match the IDAT length; it should always happen when |
| * end_of_image is set. |
| */ |
| ps->s.list = next->next; |
| |
| if (next->next == NULL) |
| { |
| debug(avail == start+len); |
| ps->s.end = &ps->s.list; |
| ps->s.zs.next_out = NULL; |
| ps->s.zs.avail_out = 0U; |
| } |
| |
| next->next = ps->stash; |
| ps->stash = next; |
| ps->s.start = 0U; |
| } |
| |
| else /* write only part of this buffer */ |
| { |
| written = len; |
| png_write_chunk_data(png_ptr, next->output+start, written); |
| ps->s.start = (unsigned int)/*SAFE*/(start + written); |
| } |
| |
| /* 'written' bytes were written: */ |
| len -= written; |
| |
| if (written <= ps->s.len) |
| ps->s.len -= written; |
| |
| else |
| { |
| affirm(ps->s.overflow > 0U); |
| --ps->s.overflow; |
| ps->s.len += 0x80000000U - written; |
| UNTESTED |
| } |
| } |
| while (len > 0U); |
| |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* avail == 0 && flush */ |
| png_end_IDAT(png_ptr); |
| png_ptr->mode |= PNG_AFTER_IDAT; |
| } |
| |
| /* This is is a convenience wrapper to handle IDAT compression; it takes a |
| * pointer to the input data and places no limit on the size of the output but |
| * is otherwise the same as png_compress(). It also handles the use of the |
| * stash (only used for IDAT compression.) |
| */ |
| static int |
| png_compress_IDAT_data(png_const_structrp png_ptr, png_zlib_statep ps, |
| png_zlib_compressp pz, png_const_voidp input, uInt input_len, int flush) |
| { |
| affirm(png_ptr->zowner == png_IDAT && pz->end != NULL && *pz->end == NULL); |
| |
| /* z_stream::{next,avail}_out are set by png_compress to point into the |
| * buffer list. next_in must be set here, avail_in comes from the input_len |
| * parameter: |
| */ |
| pz->zs.next_in = PNGZ_INPUT_CAST(png_voidcast(const Bytef*, input)); |
| *pz->end = ps->stash; /* May be NULL */ |
| ps->stash = NULL; |
| |
| /* zlib buffers the output, the maximum amount of compressed data that can be |
| * produced here is governed by the amount of buffering. |
| */ |
| { |
| int ret = png_compress(pz, input_len, 0U/*unlimited*/, flush); |
| |
| affirm(pz->end != NULL && ps->stash == NULL); |
| ps->stash = *pz->end; /* May be NULL */ |
| *pz->end = NULL; |
| |
| /* Z_FINISH should give Z_STREAM_END, everything else should give Z_OK, in |
| * either case all the input should have been consumed: |
| */ |
| implies(ret == Z_OK || ret == Z_FINISH, pz->zs.avail_in == 0U && |
| (ret == Z_STREAM_END) == (flush == Z_FINISH)); |
| pz->zs.next_in = NULL; |
| pz->zs.avail_in = 0U; /* safety */ |
| png_zlib_compress_validate(pz, 0/*in_use*/); |
| |
| return ret; |
| } |
| } |
| |
| /* Compress some image data using the main png_zlib_compress. Write the result |
| * out if there is sufficient data. png_start_IDAT must have been called. |
| */ |
| static void |
| png_compress_IDAT(png_structrp png_ptr, png_const_voidp input, uInt input_len, |
| int flush) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| int ret = png_compress_IDAT_data(png_ptr, ps, &ps->s, input, input_len, |
| flush); |
| |
| /* Check the return code. */ |
| if (ret == Z_OK || ret == Z_STREAM_END) |
| png_write_IDAT(png_ptr, flush == Z_FINISH); |
| |
| else /* ret != Z_OK && ret != Z_STREAM_END */ |
| { |
| /* This is an error condition. It is fatal. */ |
| png_end_IDAT(png_ptr); |
| png_zstream_error(&ps->s.zs, ret); |
| png_error(png_ptr, ps->s.zs.msg); |
| } |
| } |
| |
| #ifdef PNG_WRITE_FLUSH_SUPPORTED |
| /* Set the automatic flush interval or 0 to turn flushing off */ |
| void PNGAPI |
| png_set_flush(png_structrp png_ptr, int nrows) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_flush"); |
| |
| if (ps != NULL) |
| { |
| if (nrows <= 0) |
| ps->flush_dist = 0xEFFFFFFFU; |
| |
| else |
| ps->flush_dist = nrows; |
| } |
| } |
| |
| /* Flush the current output buffers now */ |
| void PNGAPI |
| png_write_flush(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_write_flush"); |
| |
| /* Before the start of the IDAT and after the end of the image zowner will be |
| * something other than png_IDAT: |
| */ |
| if (png_ptr != NULL && png_ptr->zlib_state != NULL && |
| png_ptr->zowner == png_IDAT) |
| png_ptr->zlib_state->flush_rows = 0xEFFFFFFF; |
| } |
| |
| /* Return the correct flush to use */ |
| static int |
| row_flush(png_zlib_statep ps, unsigned int row_info_flags) |
| { |
| if (PNG_IDAT_END(row_info_flags)) |
| return Z_FINISH; |
| |
| else if ((row_info_flags & png_row_end) != 0 && |
| ps->flush_rows >= ps->flush_dist) |
| return Z_SYNC_FLUSH; |
| |
| else |
| return Z_NO_FLUSH; |
| } |
| #else /* !WRITE_FLUSH */ |
| # define row_flush(ps, ri) (PNG_IDAT_END(ri) ? Z_FINISH : Z_NO_FLUSH) |
| #endif /* !WRITE_FLUSH */ |
| |
| static void |
| write_filtered_row(png_structrp png_ptr, png_const_voidp filtered_row, |
| unsigned int row_bytes, unsigned int filter /*if at start of row*/, |
| int flush) |
| { |
| /* This handles writing a row that has been filtered, or did not need to be |
| * filtered. If the data row has a partial pixel it must have been handled |
| * correctly in the caller; filters generate a full 8 bits even if the pixel |
| * only has one significant bit! |
| */ |
| debug(row_bytes > 0); |
| affirm(row_bytes <= ZLIB_IO_MAX); /* I.e. it fits in a uInt */ |
| |
| if (filter < PNG_FILTER_VALUE_LAST) /* start of row */ |
| { |
| png_byte buffer[1]; |
| |
| buffer[0] = PNG_BYTE(filter); |
| png_compress_IDAT(png_ptr, buffer, 1U/*len*/, Z_NO_FLUSH); |
| } |
| |
| png_compress_IDAT(png_ptr, filtered_row, row_bytes, flush); |
| } |
| |
| static void |
| write_unfiltered_rowbits(png_structrp png_ptr, png_const_bytep filtered_row, |
| unsigned int row_bits, png_byte filter /*if at start of row*/, |
| int flush) |
| { |
| /* Same as above, but it correctly clears the unused bits in a partial |
| * byte. |
| */ |
| const png_uint_32 row_bytes = row_bits >> 3; |
| |
| debug(filter == PNG_FILTER_VALUE_NONE || filter == PNG_FILTER_VALUE_LAST); |
| |
| if (row_bytes > 0U) |
| { |
| row_bits -= row_bytes << 3; |
| write_filtered_row(png_ptr, filtered_row, row_bytes, filter, |
| row_bits == 0U ? flush : Z_NO_FLUSH); |
| filter = PNG_FILTER_VALUE_LAST; /* written */ |
| } |
| |
| /* Handle a partial byte. */ |
| if (row_bits > 0U) |
| { |
| png_byte buffer[1]; |
| |
| buffer[0] = PNG_BYTE(filtered_row[row_bytes] & ~(0xFFU >> row_bits)); |
| write_filtered_row(png_ptr, buffer, 1U, filter, flush); |
| } |
| } |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| static void |
| filter_block_singlebyte(unsigned int row_bytes, png_bytep sub_row, |
| png_bytep up_row, png_bytep avg_row, png_bytep paeth_row, |
| png_const_bytep row, png_const_bytep prev_row, png_bytep prev_pixels) |
| { |
| /* Calculate rows for all four filters where the input has one byte per pixel |
| * (more accurately per filter-unit). |
| */ |
| png_byte a = prev_pixels[0]; |
| png_byte c = prev_pixels[1]; |
| |
| while (row_bytes-- > 0U) |
| { |
| const png_byte x = *row++; |
| const png_byte b = prev_row == NULL ? 0U : *prev_row++; |
| |
| /* Calculate each filtered byte in turn: */ |
| if (sub_row != NULL) *sub_row++ = 0xFFU & (x - a); |
| if (up_row != NULL) *up_row++ = 0xFFU & (x - b); |
| if (avg_row != NULL) *avg_row++ = 0xFFU & (x - (a+b)/2U); |
| |
| /* Paeth is a little more difficult: */ |
| if (paeth_row != NULL) |
| { |
| int pa = b-c; /* a+b-c - a */ |
| int pb = a-c; /* a+b-c - b */ |
| int pc = pa+pb; /* a+b-c - c = b-c + a-c */ |
| png_byte p = a; |
| |
| pa = abs(pa); |
| pb = abs(pb); |
| if (pa > pb) pa = pb, p = b; |
| if (pa > abs(pc)) p = c; |
| |
| *paeth_row++ = 0xFFU & (x - p); |
| } |
| |
| /* And set a and c for the next pixel: */ |
| a = x; |
| c = b; |
| } |
| |
| /* Store a and c for the next block: */ |
| prev_pixels[0] = a; |
| prev_pixels[1] = c; |
| } |
| |
| static void |
| filter_block_multibyte(unsigned int row_bytes, |
| const unsigned int bpp, png_bytep sub_row, png_bytep up_row, |
| png_bytep avg_row, png_bytep paeth_row, png_const_bytep row, |
| png_const_bytep prev_row, png_bytep prev_pixels) |
| { |
| /* Calculate rows for all four filters, the input is a block of bytes such |
| * that row_bytes is a multiple of bpp. bpp can be 2, 3, 4, 6 or 8. |
| * prev_pixels will be updated to the last pixels processed. |
| */ |
| while (row_bytes >= bpp) |
| { |
| unsigned int i; |
| |
| for (i=0; i<bpp; ++i) |
| { |
| const png_byte a = prev_pixels[i]; |
| const png_byte c = prev_pixels[i+bpp]; |
| const png_byte b = prev_row == NULL ? 0U : *prev_row++; |
| const png_byte x = *row++; |
| |
| /* Save for the next pixel: */ |
| prev_pixels[i] = x; |
| prev_pixels[i+bpp] = b; |
| |
| /* Calculate each filtered byte in turn: */ |
| if (sub_row != NULL) *sub_row++ = 0xFFU & (x - a); |
| if (up_row != NULL) *up_row++ = 0xFFU & (x - b); |
| if (avg_row != NULL) *avg_row++ = 0xFFU & (x - (a+b)/2U); |
| |
| /* Paeth is a little more difficult: */ |
| if (paeth_row != NULL) |
| { |
| int pa = b-c; /* a+b-c - a */ |
| int pb = a-c; /* a+b-c - b */ |
| int pc = pa+pb; /* a+b-c - c = b-c + a-c */ |
| png_byte p = a; |
| |
| pa = abs(pa); |
| pb = abs(pb); |
| if (pa > pb) pa = pb, p = b; |
| if (pa > abs(pc)) p = c; |
| |
| *paeth_row++ = 0xFFU & (x - p); |
| } |
| } |
| |
| row_bytes -= i; |
| } |
| } |
| |
| static void |
| filter_block(png_const_bytep prev_row, png_bytep prev_pixels, |
| png_const_bytep unfiltered_row, unsigned int row_bits, |
| const unsigned int bpp, png_bytep sub_row, png_bytep up_row, |
| png_bytep avg_row, png_bytep paeth_row) |
| { |
| const unsigned int row_bytes = row_bits >> 3; /* complete bytes */ |
| |
| if (bpp <= 8U) |
| { |
| /* There may be a partial byte at the end. */ |
| if (row_bytes > 0) |
| filter_block_singlebyte(row_bytes, sub_row, up_row, avg_row, paeth_row, |
| unfiltered_row, prev_row, prev_pixels); |
| |
| /* The partial byte must be handled correctly here; both the previous row |
| * value and the current value need to have non-present bits cleared. |
| */ |
| if ((row_bits & 7U) != 0) |
| { |
| const png_byte mask = PNG_BYTE(~(0xFFU >> (row_bits & 7U))); |
| png_byte buffer[2]; |
| |
| buffer[0] = unfiltered_row[row_bytes] & mask; |
| |
| if (prev_row != NULL) |
| buffer[1U] = prev_row[row_bytes] & mask; |
| |
| else |
| buffer[1U] = 0U; |
| |
| filter_block_singlebyte(1U, |
| sub_row == NULL ? NULL : sub_row+row_bytes, |
| up_row == NULL ? NULL : up_row+row_bytes, |
| avg_row == NULL ? NULL : avg_row+row_bytes, |
| paeth_row == NULL ? NULL : paeth_row+row_bytes, |
| buffer, buffer+1U, prev_pixels); |
| } |
| } |
| |
| else |
| filter_block_multibyte(row_bytes, bpp >> 3, |
| sub_row, up_row, avg_row, paeth_row, |
| unfiltered_row, prev_row, prev_pixels); |
| } |
| |
| static void |
| filter_row(png_structrp png_ptr, png_const_bytep prev_row, |
| png_bytep prev_pixels, png_const_bytep unfiltered_row, |
| unsigned int row_bits, unsigned int bpp, unsigned int filter, |
| int start_of_row, int flush) |
| { |
| /* filters_to_try identifies a single filter and it is not PNG_FILTER_NONE. |
| */ |
| png_byte filtered_row[PNG_ROW_BUFFER_SIZE]; |
| |
| affirm((row_bits+7U) >> 3 <= PNG_ROW_BUFFER_SIZE && |
| filter >= PNG_FILTER_VALUE_SUB && filter <= PNG_FILTER_VALUE_PAETH); |
| debug((row_bits % bpp) == 0U); |
| |
| filter_block(prev_row, prev_pixels, unfiltered_row, row_bits, bpp, |
| filter == PNG_FILTER_VALUE_SUB ? filtered_row : NULL, |
| filter == PNG_FILTER_VALUE_UP ? filtered_row : NULL, |
| filter == PNG_FILTER_VALUE_AVG ? filtered_row : NULL, |
| filter == PNG_FILTER_VALUE_PAETH ? filtered_row : NULL); |
| |
| write_filtered_row(png_ptr, filtered_row, (row_bits+7U)>>3, |
| start_of_row ? filter : PNG_FILTER_VALUE_LAST, flush); |
| } |
| |
| #ifdef PNG_SELECT_FILTER_HEURISTICALLY_SUPPORTED |
| static png_byte |
| select_filter_heuristically(png_structrp png_ptr, unsigned int filters_to_try, |
| png_const_bytep prev_row, png_bytep prev_pixels, |
| png_const_bytep unfiltered_row, unsigned int row_bits, unsigned int bpp, |
| int flush) |
| { |
| const unsigned int row_bytes = (row_bits+7U) >> 3; |
| png_byte test_buffers[4][PNG_ROW_BUFFER_SIZE]; /* for each filter */ |
| |
| affirm(row_bytes <= PNG_ROW_BUFFER_SIZE); |
| debug((row_bits % bpp) == 0U); |
| |
| filter_block(prev_row, prev_pixels, unfiltered_row, row_bits, bpp, |
| test_buffers[PNG_FILTER_VALUE_SUB-1U], |
| test_buffers[PNG_FILTER_VALUE_UP-1U], |
| test_buffers[PNG_FILTER_VALUE_AVG-1U], |
| test_buffers[PNG_FILTER_VALUE_PAETH-1U]); |
| |
| /* Now check each buffer and the original row to see which is best; this is |
| * the heuristic. The test is on the number of separate code values in the |
| * buffer. Since the buffer is either the full row or PNG_ROW_BUFFER_SIZE |
| * bytes (or slightly less for RGB) we either find the true number of codes |
| * generated or we expect a count of average 8 per code. |
| */ |
| { |
| unsigned int filter_max = 257U; |
| png_byte best_filter, test_filter; |
| png_const_bytep best_row, test_row; |
| |
| for (best_filter = test_filter = PNG_FILTER_VALUE_NONE, |
| best_row = test_row = unfiltered_row; |
| test_filter < PNG_FILTER_VALUE_LAST; |
| test_row = test_buffers[test_filter], ++test_filter) |
| if ((filters_to_try & PNG_FILTER_MASK(test_filter)) != 0U) |
| { |
| unsigned int count = 1U, x; |
| png_byte code[256]; |
| |
| memset(code, 0, sizeof code); |
| code[test_filter] = 1U; |
| |
| for (x=0U; x < row_bytes; ++x) |
| { |
| const png_byte b = test_row[x]; |
| if (code[b] == 0) code[b] = 1U, ++count; |
| } |
| |
| if (count < filter_max) |
| filter_max = count, best_filter = test_filter, best_row = test_row; |
| } |
| |
| /* Calling write_unfiltered_rowbits is necessary here to deal with the |
| * clearly of a partial byte at the end. |
| */ |
| if (best_filter == PNG_FILTER_VALUE_NONE) |
| write_unfiltered_rowbits(png_ptr, unfiltered_row, row_bits, |
| PNG_FILTER_VALUE_NONE, flush); |
| |
| else |
| write_filtered_row(png_ptr, best_row, row_bytes, best_filter, |
| flush); |
| |
| return best_filter; |
| } |
| } |
| #endif /* SELECT_FILTER_HEURISTICALLY */ |
| |
| #ifdef PNG_SELECT_FILTER_METHODICALLY_SUPPORTED |
| /* With the 'methodical' method multiple png_zlib_compress structures exist, |
| * these functions handle the creation and destruction ('release') of these |
| * structures. Note that the structures have not been initialized with the |
| * opaque and alloc functions; this is done on demand and the 'opaque' pointer |
| * is set to NULL if the compress structure is not in use. |
| */ |
| static void |
| png_zlib_filter_release(png_structrp png_ptr, png_zlib_statep ps, png_byte i) |
| { |
| /* Make sure this filter really is in use: */ |
| if (ps->filter[i].zs.opaque != NULL) /* else not initialized */ |
| { |
| /* First put the buffer list back into the cache, when this function is |
| * called the list should be correctly terminated at *end. |
| */ |
| { |
| png_compression_bufferp list = ps->filter[i].list; |
| |
| if (list != NULL) |
| { |
| ps->filter[i].list = NULL; |
| |
| /* Return the list to the stash. */ |
| affirm(ps->filter[i].end != NULL); |
| |
| /* In the normal case 'end' is the end of this list and it is |
| * pre-pended to the cache. In the error case (png_error during a |
| * deflate operation) the list will be the entire stash and the |
| * stash will be NULL. |
| * |
| * If both pointers are non-NULL clean up by making the 'end' |
| * pointer NULL (freeing anything it points to). This is |
| * unexpected. |
| */ |
| if (ps->stash != NULL) |
| { |
| debug(*ps->filter[i].end == NULL); |
| /* Clean up on error: */ |
| png_free_compression_buffer(png_ptr, ps->filter[i].end); |
| *ps->filter[i].end = ps->stash; |
| } |
| |
| ps->stash = list; |
| } |
| |
| ps->filter[i].end = &ps->filter[i].list; /* safety */ |
| } |
| |
| /* Now use the standard 'destroy' function to handle the z_stream; the |
| * list has already been made NULL above. If the structure is sharing |
| * state with the main compress structure do not free it! |
| */ |
| if (ps->filter[i].zs.state != ps->s.zs.state) |
| png_zlib_compress_destroy(&ps->filter[i], 0/*check*/); |
| |
| /* Then this indicates that the structure is not in use: */ |
| ps->filter[i].zs.opaque = NULL; |
| } |
| |
| else |
| debug(ps->filter[i].list == NULL); |
| } |
| |
| static int /* success */ |
| png_zlib_filter_compress(png_structrp png_ptr, png_zlib_statep ps, png_byte i, |
| png_const_voidp input, uInt input_len, int flush) |
| { |
| png_zlib_compressp pz = &ps->filter[i]; |
| int ret = png_compress_IDAT_data(png_ptr, ps, pz, input, input_len, flush); |
| |
| if (ret == Z_OK || ret == Z_STREAM_END) |
| return 1; /* success */ |
| |
| else |
| { |
| /* If ret is not Z_OK then this stream gets aborted, this is recoverable |
| * so long as this is not the only stream left. There are only two likely |
| * causes of failure; an internal libpng bug or out-of-memory. Given an |
| * assumption of infalibility this means that the app is out of memory and |
| * it makes sense to release as much as possible. Note that it is |
| * conceivable that OOM may cause an error other than Z_MEM_ERROR, though |
| * this is unlikely. |
| */ |
| png_zstream_error(&pz->zs, ret); |
| png_warning(png_ptr, pz->zs.msg); |
| png_zlib_filter_release(png_ptr, ps, i); |
| return 0; /* failure */ |
| } |
| } |
| |
| static int /* success */ |
| png_zlib_filter_init(png_structrp png_ptr, png_zlib_statep ps, png_byte i, |
| int copy) |
| { |
| png_zlib_compressp pz = &ps->filter[i]; |
| |
| /* Make sure that we don't overwrite previously allocated stuff: */ |
| debug(pz->zs.opaque == NULL && pz->list == NULL); |
| |
| /* Initialize the list and count fields: */ |
| pz->end = &pz->list; |
| pz->len = 0U; |
| pz->overflow = 0U; |
| pz->start = 0U; |
| |
| /* If 'copy' is true a complete copy is made of the main z_stream, otherwise |
| * the stream is shared. deflateCopy actually does a memcpy over the |
| * destination z_stream, so no further initialization is required. |
| */ |
| if (copy) |
| { |
| int ret = deflateCopy(&pz->zs, &ps->s.zs); |
| |
| if (ret != Z_OK) |
| { |
| /* If this fails and png_chunk_report returns we can continue because |
| * the caller handles the error: |
| */ |
| pz->zs.opaque = NULL; |
| png_zstream_error(&pz->zs, ret); |
| png_chunk_report(png_ptr, pz->zs.msg, PNG_CHUNK_WRITE_ERROR); |
| return 0; |
| } |
| } |
| |
| else |
| pz->zs = ps->s.zs; /* see png_zlib_filter_release */ |
| |
| /* Either way the {next,avail}_{in.out} fields got copied, however they must |
| * not be used so: |
| */ |
| ps->filter[i].zs.next_in = ps->filter[i].zs.next_out = NULL; |
| ps->filter[i].zs.avail_in = ps->filter[i].zs.avail_out = 0U; |
| ps->filter[i].zs.msg = PNGZ_MSG_CAST("zlib copy ok"); /* safety */ |
| |
| /* If there is a partial buffer in the main stream a partial buffer is |
| * required here: |
| */ |
| { |
| uInt start = ps->s.zs.avail_out; |
| |
| if (start > 0U && start < sizeof ps->s.list->output) |
| { |
| uInt avail_out; |
| |
| start = (uInt)/*SAFE*/(sizeof ps->s.list->output) - start; |
| pz->list = ps->stash; |
| ps->stash = NULL; |
| avail_out = png_zlib_compress_avail_out(pz); |
| ps->stash = *pz->end; |
| *pz->end = NULL; |
| |
| if (avail_out >= start) |
| { |
| pz->zs.next_out += start; |
| pz->zs.avail_out -= start; |
| pz->start = start; |
| } |
| |
| else /* OOM */ |
| { |
| png_warning(png_ptr, "filter selection: out of memory"); |
| png_zlib_filter_release(png_ptr, ps, i); |
| return 0; /* failure */ |
| } |
| } |
| } |
| |
| /* Finally compress the filter byte into the copied/shared z_stream. */ |
| { |
| png_byte b[1]; |
| |
| b[0] = i; |
| return png_zlib_filter_compress(png_ptr, ps, i, b, 1U, Z_NO_FLUSH); |
| } |
| } |
| |
| /* Revert to using the main z_stream. This just moves the given filter (which |
| * must have been initialized) back to the main stream leaving the filter ready |
| * to be released. |
| */ |
| static void |
| png_zlib_filter_revert(png_structrp png_ptr, png_zlib_statep ps, png_byte i) |
| { |
| png_zlib_compressp pz = &ps->filter[i]; |
| |
| affirm(pz->zs.opaque != NULL); |
| png_zlib_compress_validate(pz, 0/*in_use*/); |
| |
| /* First merge the buffer lists. */ |
| if (pz->overflow > 0U || pz->len > 0U) |
| { |
| affirm(pz->list != NULL); |
| debug(ps->s.end != NULL && *ps->s.end == NULL); |
| |
| /* The deflate operation produced some output, if pz->start is non-zero |
| * the first buffer in pz->list must be merged with the current buffer in |
| * the main z_stream, if pz->zs.next_out still points into this buffer the |
| * pointer must be updated to point to the old buffer. |
| */ |
| if (ps->s.zs.avail_out > 0U) |
| { |
| affirm(ps->s.zs.avail_out + pz->start == sizeof ps->s.list->output); |
| /* Copy everything after pz->start into the old buffer. */ |
| memcpy(ps->s.zs.next_out, pz->list->output + pz->start, |
| ps->s.zs.avail_out); |
| |
| /* Unlink the remainder of the list, if any, and append it to the |
| * output. |
| */ |
| if (pz->list->next != NULL) |
| { |
| debug(pz->end != &pz->list->next); |
| *ps->s.end = pz->list->next; |
| pz->list->next = NULL; |
| ps->s.end = pz->end; |
| pz->end = &pz->list->next; /* To be deleted later */ |
| } |
| |
| /* If pz->s.next_out still points into the first buffer (the case for |
| * the final row of small images) update it to point to the old buffer |
| * instead so that the copy below works. |
| */ |
| if (pz->zs.next_out >= pz->list->output && |
| pz->zs.next_out <= pz->list->output + (sizeof pz->list->output)) |
| { |
| debug(pz->overflow == 0U && |
| pz->len + pz->start <= (sizeof pz->list->output) && |
| pz->zs.next_out + pz->zs.avail_out == |
| pz->list->output + (sizeof pz->list->output) && |
| ps->s.zs.avail_out > pz->zs.avail_out); |
| pz->zs.next_out = ps->s.zs.next_out + ps->s.zs.avail_out - |
| pz->zs.avail_out; |
| } |
| } |
| |
| else |
| { |
| affirm(pz->start == 0U); |
| |
| /* Nothing to copy, the whole new list is appended to the existing one. |
| */ |
| *ps->s.end = pz->list; |
| pz->list = NULL; |
| ps->s.end = pz->end; |
| pz->end = &pz->list; |
| } |
| |
| /* Update the length fields; 'start' remains correct. */ |
| ps->s.overflow += pz->overflow; |
| if (((ps->s.len += pz->len) & 0x80000000U) != 0) |
| ++ps->s.overflow, ps->s.len &= 0x7FFFFFFFU; |
| } |
| |
| else |
| { |
| /* deflate produced no additional output; all the state is in the |
| * z_stream. Copy it back without changing anything else. |
| */ |
| debug(pz->zs.avail_out == ps->s.zs.avail_out); |
| pz->zs.next_out = ps->s.zs.next_out; |
| } |
| |
| /* The buffer list has been fixed, the z_stream must be copied. All fields |
| * are relevant. This is done as a simple swap. |
| */ |
| { |
| z_stream zs = ps->s.zs; |
| |
| ps->s.zs = pz->zs; |
| png_zlib_compress_validate(&ps->s, 0/*in_use*/); |
| zs.next_in = zs.next_out = NULL; |
| zs.avail_in = zs.avail_out = 0U; |
| zs.msg = PNGZ_MSG_CAST("invalid"); |
| pz->zs = zs; |
| } |
| } |
| |
| /* As above but release all the filters as well. */ |
| static void |
| png_zlib_filter_revert_and_release(png_structrp png_ptr, png_zlib_statep ps, |
| png_byte i) |
| { |
| /* The other filters must be released first to correctly handle the |
| * non-copied one: |
| */ |
| png_byte f; |
| |
| for (f=0U; f < PNG_FILTER_VALUE_LAST; ++f) |
| if (f != i) |
| png_zlib_filter_release(png_ptr, ps, f); |
| |
| png_zlib_filter_revert(png_ptr, ps, i); |
| png_zlib_filter_release(png_ptr, ps, i); |
| } |
| |
| static png_byte /* filters being tried */ |
| select_filter_methodically_init(png_structrp png_ptr, |
| const unsigned int filters_to_try) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| |
| affirm(ps != NULL); |
| |
| /* Now activate the decompressor for each filter in the list. Skip the first |
| * filter; this will share the main state. |
| */ |
| { |
| unsigned int filters = 0U; |
| png_byte filter, first_filter = PNG_FILTER_VALUE_LAST; |
| |
| for (filter=0U; filter < PNG_FILTER_VALUE_LAST; ++filter) |
| if ((filters_to_try & PNG_FILTER_MASK(filter)) != 0U) |
| { |
| if (first_filter == PNG_FILTER_VALUE_LAST) |
| first_filter = filter; |
| |
| else if (png_zlib_filter_init(png_ptr, ps, filter, 1/*copy*/)) |
| filters |= PNG_FILTER_MASK(filter); |
| |
| else /* OOM, probably; give up */ |
| { |
| ps->filter_oom = 1U; |
| break; |
| } |
| } |
| |
| /* If none of that worked abort the filter selection by returning just the |
| * first filter. Note that a filter value is returned here. |
| */ |
| if (filters == 0U) |
| return first_filter; |
| |
| /* Finally initialize the first filter. */ |
| if (png_zlib_filter_init(png_ptr, ps, first_filter, 0/*!copy*/)) |
| return PNG_ALL_FILTERS & (filters | PNG_FILTER_MASK(first_filter)); |
| |
| /* This is an error condition but there is still a working z_stream |
| * structure. The z_stream has had the filter byte written to it, so teh |
| * standard code cannot be used. Simply fake the multi-filter case. The |
| * low three bits ensure that there are multiple bits in the result. |
| */ |
| ps->filter_oom = 1U; |
| return PNG_ALL_FILTERS & (filters | 0x7U); |
| } |
| } |
| |
| static int |
| select_filter_methodically_better(png_structrp png_ptr, png_zlib_compressp pz, |
| png_uint_32p op/*high 32 bits*/, png_uint_32p lp/*low 31 bits*/, |
| Bytef *scratch_out, uInt avail_out, int flush) |
| /* Called at the end of a row for each filter being tested to work out if |
| * this filter is apparently producing better results than {*op,*lp}, which |
| * is preset to a number larger than any possible 63-bit value and then set, |
| * here, as required to {overflow,len} from a selected filter. |
| */ |
| { |
| /* The pre-check here is that the data already produced by the compression |
| * engine does not exceed the best count found so far: |
| */ |
| png_uint_32 o = pz->overflow, l = pz->len; |
| |
| png_zlib_compress_validate(pz, 0/*in_use*/); |
| |
| if (o < *op || (o == *op && l < *lp)) |
| { |
| /* But if the stream hasn't been flushed this proves nothing; test the |
| * pending output by using an appropriate flush: |
| */ |
| if (flush == Z_NO_FLUSH) |
| { |
| int ret; |
| z_stream zs; |
| |
| ret = deflateCopy(&zs, &pz->zs); |
| |
| if (ret == Z_OK) |
| { |
| zs.next_in = NULL; |
| zs.avail_in = 0U; |
| |
| /* Extract all the output from zlib by doing dummy deflates. Note |
| * that all the flush possibilites give approximately the same |
| * result but PARTIAL, SYNC and FULL seem to be mildly better |
| * probably because they avoid the rounding and block overhead. |
| * |
| * Z_PARTIAL_FLUSH 1 |
| * Z_SYNC_FLUSH 2 |
| * Z_FULL_FLUSH 3 |
| * Z_FINISH 4 |
| * Z_BLOCK 5 |
| */ |
| flush = Z_PARTIAL_FLUSH; |
| |
| do |
| { |
| if (l & 0x80000000U) |
| ++o, l &= 0x7FFFFFFFU; |
| |
| zs.next_out = scratch_out; |
| zs.avail_out = avail_out; |
| l += avail_out; |
| |
| ret = deflate(&zs, flush); |
| } while (ret == Z_OK && zs.avail_out == 0U); |
| |
| #if 0 |
| /* TODO: fix this (Coverity issue Z_STREAM_END is dead code) */ |
| if (ret == (flush == Z_FINISH ? Z_STREAM_END : Z_OK)) |
| #else |
| if (ret == Z_OK) |
| #endif /* 0 */ |
| { |
| /* This cannot underflow because the check above is performed |
| * before adding 'avail_out' to l: |
| */ |
| l -= zs.avail_out; |
| (void)deflateEnd(&zs); |
| png_zlib_compress_validate(pz, 0/*in_use*/); |
| |
| if (l & 0x80000000U) |
| ++o, l &= 0x7FFFFFFFU; |
| |
| if (o < *op || (o == *op && l < *lp)) |
| { |
| *op = o; |
| *lp = l; |
| return 1; |
| } |
| |
| /* No errors but the result was longer (this can't be the first |
| * filter.) |
| */ |
| return 0; |
| } |
| |
| else /* problem in deflate */ |
| (void)deflateEnd(&zs); |
| } |
| |
| /* We arrive here if there was an error somewhere inside zlib. */ |
| png_zstream_error(&zs, ret); |
| png_warning(png_ptr, zs.msg); |
| } |
| |
| else /* flush already performed */ |
| { |
| *op = o; |
| *lp = l; |
| return 1; |
| } |
| } |
| |
| /* This is the failure case, however if this is the first filter to be tested |
| * return success anyway, without resetting {op,lp}: |
| */ |
| return *op == 0xFFFFFFFFU && *lp == 0xFFFFFFFFU; |
| } |
| |
| static void |
| select_filter_methodically(png_structrp png_ptr, png_const_bytep prev_row, |
| png_bytep prev_pixels, png_const_bytep unfiltered_row, |
| unsigned int row_bits, unsigned int bpp, unsigned int filters_to_try, |
| int end_of_row, int flush) |
| { |
| png_zlib_statep ps = png_ptr->zlib_state; |
| const unsigned int row_bytes = (row_bits+7U) >> 3; |
| png_byte test_buffers[4][PNG_ROW_BUFFER_SIZE]; /* for each filter */ |
| |
| affirm(row_bytes <= PNG_ROW_BUFFER_SIZE && ps != NULL); |
| debug((row_bits % bpp) == 0U && filters_to_try > 0x7U); |
| |
| filter_block(prev_row, prev_pixels, unfiltered_row, row_bits, bpp, |
| test_buffers[PNG_FILTER_VALUE_SUB-1U], |
| test_buffers[PNG_FILTER_VALUE_UP-1U], |
| test_buffers[PNG_FILTER_VALUE_AVG-1U], |
| test_buffers[PNG_FILTER_VALUE_PAETH-1U]); |
| |
| /* Add each test buffer, and the unfiltered row if required, to the current |
| * list. |
| */ |
| { |
| png_byte filter, ok_filter = PNG_FILTER_VALUE_LAST; |
| |
| for (filter=0U; filter < PNG_FILTER_VALUE_LAST; ++filter) |
| if ((filters_to_try & PNG_FILTER_MASK(filter)) != 0U) |
| { |
| if (png_zlib_filter_compress(png_ptr, ps, filter, |
| filter == PNG_FILTER_VALUE_NONE ? |
| unfiltered_row : test_buffers[filter-1], row_bytes, flush)) |
| ok_filter = filter; |
| |
| else /* remove this filter from the test list: */ |
| filters_to_try &= PNG_BIC_MASK(PNG_FILTER_MASK(filter)); |
| } |
| |
| /* If nothing worked then there is no recovery possible. */ |
| if (ok_filter == PNG_FILTER_VALUE_LAST) |
| png_error(png_ptr, "filter selection: everything failed"); |
| |
| /* At end_of_row choose the best filter; it is stored in ok_filter. */ |
| if (end_of_row) |
| { |
| png_uint_32 o, l; |
| |
| o = l = 0xFFFFFFFFU; |
| ok_filter = PNG_FILTER_VALUE_LAST; |
| |
| for (filter=0U; filter < PNG_FILTER_VALUE_LAST; ++filter) |
| if ((filters_to_try & PNG_FILTER_MASK(filter)) != 0U && |
| select_filter_methodically_better(png_ptr, &ps->filter[filter], |
| &o, &l, test_buffers[0], sizeof test_buffers, flush)) |
| ok_filter = filter; |
| } |
| |
| /* Keep going if there is more than one filter left, otherwise, if there |
| * is only one left (because of OOM killing filters) swap back to the |
| * main-line code using 'ok_filter'. |
| */ |
| else if ((filters_to_try & (filters_to_try-1U)) != 0U) |
| ok_filter = PNG_FILTER_VALUE_LAST; /* keep going */ |
| |
| /* Swap back to the mainline code at end of row or when the available |
| * filter count drops to one because of OOM. |
| */ |
| if (ok_filter < PNG_FILTER_VALUE_LAST) |
| { |
| png_zlib_filter_revert_and_release(png_ptr, ps, ok_filter); |
| png_write_IDAT(png_ptr, flush == Z_FINISH); |
| ps->filters = ok_filter; |
| } |
| |
| else |
| { |
| ps->filters = PNG_ALL_FILTERS & (filters_to_try &= PNG_ALL_FILTERS); |
| debug((filters_to_try & (filters_to_try-1U)) != 0U); |
| } |
| } |
| } |
| #endif /* SELECT_FILTER_METHODICALLY */ |
| |
| /* 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. |
| */ |
| void /* PRIVATE */ |
| png_write_filter_row(png_structrp png_ptr, png_bytep prev_pixels, |
| png_const_bytep unfiltered_row, png_uint_32 x, |
| unsigned int width/*pixels*/, unsigned int row_info_flags) |
| { |
| png_zlib_statep ps; |
| png_bytep prev_row = png_ptr->row_buffer; |
| const unsigned int bpp = png_ptr->row_output_pixel_depth; |
| const unsigned int row_bits = width * bpp; |
| unsigned int filters_to_try; |
| int flush; |
| |
| /* These invariants are expected from the caller: */ |
| affirm(width < 65536U && bpp <= 64U && width < 65536U/bpp && |
| row_bits <= 8U*PNG_ROW_BUFFER_SIZE); |
| |
| /* Set up the IDAT zlib compression if not set up yet: */ |
| if (png_ptr->zowner != png_IDAT) |
| png_start_IDAT(png_ptr); |
| |
| ps = png_ptr->zlib_state; |
| affirm(ps != NULL); |
| flush = row_flush(ps, row_info_flags); |
| |
| if (x == 0U) /* start of row */ |
| { |
| /* Now work out the filters to try for this row: */ |
| filters_to_try = ps->filter_mask; |
| |
| /* If this has a previous row filter in the set to try ensure the row |
| * buffer exists and ensure it is empty when first allocated and at |
| * the start of the pass. |
| */ |
| if ((filters_to_try & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) |
| != 0U) |
| { |
| if (prev_row == NULL) |
| { |
| /* Just allocate for the total output row bytes; a three-row |
| * interlaced image requires less, but this is safe. |
| */ |
| prev_row = png_voidcast(png_bytep, png_malloc(png_ptr, |
| png_calc_rowbytes(png_ptr, bpp, png_ptr->width))); |
| png_ptr->row_buffer = prev_row; |
| |
| /* If that buffer would have been required for this row issue an |
| * app warning and disable the filters that would have required |
| * the data. |
| */ |
| if (!(row_info_flags & png_pass_first_row)) |
| { |
| png_app_warning(png_ptr, "Previous row filters ignored"); |
| /* And always turn off the filters, to prevent using |
| * uninitialized data. |
| */ |
| filters_to_try &= PNG_BIC_MASK( |
| PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH); |
| |
| if (filters_to_try == 0U) |
| filters_to_try = PNG_FILTER_NONE; |
| } |
| } |
| } |
| |
| if ((row_info_flags & png_pass_first_row) != 0U) |
| { |
| /* On the first row UP and NONE are the same, PAETH and SUB are the |
| * same, so if both members of a pair occur together eliminate the one |
| * that depends on the previous row. This will avoid the filter |
| * selection code while allowing the app to ensure all the filters can |
| * be used (prev_row is allocated) on the first row. |
| */ |
| # define match(mask) (filters_to_try & (mask)) == mask |
| if (match(PNG_FILTER_NONE+PNG_FILTER_UP)) |
| filters_to_try &= PNG_BIC_MASK(PNG_FILTER_UP); |
| |
| if (match(PNG_FILTER_SUB+PNG_FILTER_PAETH)) |
| filters_to_try &= PNG_BIC_MASK(PNG_FILTER_PAETH); |
| # undef match |
| } |
| |
| /* If there is no selection algorithm enabled choose the first filter |
| * in the list, otherwise do algorithm-specific initialization. |
| */ |
| if ((filters_to_try & (filters_to_try-1U)) != 0U) |
| { |
| /* Multiple filters in the list. */ |
| # ifdef PNG_SELECT_FILTER_METHODICALLY_SUPPORTED |
| if (!ps->filter_oom && |
| (methodical_option == PNG_OPTION_ON || |
| (methodical_option != PNG_OPTION_OFF && |
| heuristic_option != PNG_OPTION_ON))) |
| filters_to_try = |
| select_filter_methodically_init(png_ptr, filters_to_try); |
| |
| else /* don't do methodical selection */ |
| # endif /* SELECT_FILTER_METHODICALLY */ |
| # ifdef PNG_SELECT_FILTER_HEURISTICALLY_SUPPORTED |
| if (heuristic_option != PNG_OPTION_OFF) /* use heuristics */ |
| { |
| /* The heuristic must select a single filter based on the first |
| * block of pixels; it updates zbuffer_filter to a single filter |
| * value. |
| */ |
| ps->filters = select_filter_heuristically(png_ptr, |
| filters_to_try, |
| (row_info_flags & png_pass_first_row) ? NULL : prev_row, |
| prev_pixels, unfiltered_row, row_bits, bpp, flush); |
| |
| /* This has selected one filter and has already processed it but |
| * the current row must still be retained regardless if prev_row |
| * is non-NULL. |
| */ |
| goto copy_row; |
| } |
| |
| else /* don't use heuristic selection */ |
| # endif /* SELECT_FILTER_HEURISTICALLY */ |
| filters_to_try &= -filters_to_try; |
| } |
| |
| /* If there is just one bit set in filters_to_try convert it to the filter |
| * value and store that. |
| */ |
| if ((filters_to_try & (filters_to_try-1U)) == 0U) switch (filters_to_try) |
| { |
| case PNG_FILTER_NONE: filters_to_try = PNG_FILTER_VALUE_NONE; break; |
| case PNG_FILTER_SUB: filters_to_try = PNG_FILTER_VALUE_SUB; break; |
| case PNG_FILTER_UP: filters_to_try = PNG_FILTER_VALUE_UP; break; |
| case PNG_FILTER_AVG: filters_to_try = PNG_FILTER_VALUE_AVG; break; |
| case PNG_FILTER_PAETH: filters_to_try = PNG_FILTER_VALUE_PAETH; break; |
| default: |
| impossible("bad filter mask"); |
| } |
| |
| ps->filters = PNG_ALL_FILTERS & filters_to_try; |
| } /* start of row */ |
| |
| else |
| { |
| if (prev_row != NULL) |
| { |
| /* Advance prev_row to the corresponding pixel above row[x], must use |
| * png_calc_rowbytes here otherwise the calculation using x might |
| * overflow. |
| */ |
| debug(((x * bpp) & 7U) == 0U); |
| prev_row += png_calc_rowbytes(png_ptr, bpp, x); |
| } |
| |
| filters_to_try = ps->filters; |
| } |
| |
| /* Now choose the correct filter implementation according to the number of |
| * filters in the filters_to_try list. The prev_row parameter is made NULL |
| * on the first row because it is uninitialized at that point. |
| */ |
| if (filters_to_try == PNG_FILTER_VALUE_NONE) |
| write_unfiltered_rowbits(png_ptr, unfiltered_row, row_bits, |
| x == 0 ? PNG_FILTER_VALUE_NONE : PNG_FILTER_VALUE_LAST, flush); |
| |
| else |
| { |
| png_const_bytep prev = |
| (row_info_flags & png_pass_first_row) ? NULL : prev_row; |
| |
| /* Is just one bit set in 'filters_to_try'? */ |
| if (filters_to_try < PNG_FILTER_VALUE_LAST) |
| filter_row(png_ptr, prev, prev_pixels, unfiltered_row, row_bits, bpp, |
| filters_to_try, x == 0, flush); |
| |
| else |
| # ifdef PNG_SELECT_FILTER_METHODICALLY_SUPPORTED |
| select_filter_methodically(png_ptr, prev, prev_pixels, |
| unfiltered_row, row_bits, bpp, filters_to_try, |
| (row_info_flags & png_row_end) != 0U, flush); |
| # else |
| impossible("bad filter select logic"); |
| # endif /* SELECT_FILTER_METHODICALLY */ |
| } |
| |
| # ifdef PNG_WRITE_FLUSH_SUPPORTED |
| if (flush == Z_SYNC_FLUSH) |
| { |
| png_flush(png_ptr); |
| ps->flush_rows = 0U; |
| } |
| # endif /* WRITE_FLUSH */ |
| |
| /* Copy the current row into the previous row buffer, if available, unless |
| * this is the last row in the pass, when there is no point. Note that |
| * prev_row may have garbage in a partial byte at the end. |
| */ |
| copy_row: |
| if (prev_row != NULL && !(row_info_flags & png_pass_last_row)) |
| memcpy(prev_row, unfiltered_row, (row_bits + 7U) >> 3); |
| } |
| |
| /* Allow the application to select one or more row filters to use. */ |
| void PNGAPI |
| png_set_filter(png_structrp png_ptr, int method, int filtersIn) |
| { |
| unsigned int filters; |
| |
| png_debug(1, "in png_set_filter"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| if (method != png_ptr->filter_method) |
| { |
| png_app_error(png_ptr, "png_set_filter: method does not match IHDR"); |
| return; |
| } |
| |
| /* PNG and MNG use the same base adaptive filter types: */ |
| if (method != PNG_FILTER_TYPE_BASE && method != PNG_INTRAPIXEL_DIFFERENCING) |
| { |
| png_app_error(png_ptr, "png_set_filter: unsupported method"); |
| return; |
| } |
| |
| /* Notice that PNG_NO_FILTERS is 0 and passes this test; this is OK |
| * because filters then gets set to PNG_FILTER_NONE, as is required. |
| */ |
| if (filtersIn >= 0 && filtersIn < PNG_FILTER_VALUE_LAST) |
| filters = 8U << filtersIn; |
| |
| else if ((filtersIn & PNG_BIC_MASK(PNG_ALL_FILTERS)) == 0) |
| filters = filtersIn & PNG_ALL_FILTERS; |
| |
| else |
| { |
| png_app_error(png_ptr, "png_set_filter: invalid filters mask/value"); |
| |
| /* Prior to 1.7.0 this ignored the error and just used the bits that |
| * are present, now it does nothing; this seems a lot safer. |
| */ |
| return; |
| } |
| |
| debug(filters != 0U && (filters & PNG_BIC_MASK(PNG_ALL_FILTERS)) == 0U); |
| |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| if (ps != NULL) |
| ps->filter_mask = png_check_bits(png_ptr, filters, 8); |
| |
| else |
| png_app_error(png_ptr, "png_set_filter: invalid on read struct"); |
| } |
| } |
| #else /* !WRITE_FILTER */ |
| void /* PRIVATE */ |
| png_write_filter_row(png_structrp png_ptr, png_bytep prev_pixels, |
| png_const_bytep unfiltered_row, png_uint_32 x, |
| unsigned int width/*pixels*/, unsigned int row_info_flags) |
| { |
| const unsigned int bpp = png_ptr->row_output_pixel_depth; |
| int flush; |
| png_uint_32 row_bits; |
| |
| row_bits = width; |
| row_bits *= bpp; |
| /* These invariants are expected from the caller: */ |
| affirm(width < 65536U && bpp <= 64U && width < 65536U/bpp && |
| row_bits <= 8U*PNG_ROW_BUFFER_SIZE); |
| |
| /* Set up the IDAT zlib compression if not set up yet: */ |
| if (png_ptr->zowner != png_IDAT) |
| png_start_IDAT(png_ptr); |
| |
| affirm(png_ptr->zlib_state != NULL); |
| flush = row_flush(png_ptr->zlib_state, row_info_flags); |
| |
| write_unfiltered_rowbits(png_ptr, unfiltered_row, row_bits, |
| x == 0 ? PNG_FILTER_VALUE_NONE : PNG_FILTER_VALUE_LAST, flush); |
| |
| # ifdef PNG_WRITE_FLUSH_SUPPORTED |
| if (flush == Z_SYNC_FLUSH) |
| { |
| png_flush(png_ptr); |
| png_ptr->zlib_state->flush_rows = 0U; |
| } |
| # endif /* WRITE_FLUSH */ |
| |
| PNG_UNUSED(prev_pixels); |
| } |
| #endif /* !WRITE_FILTER */ |
| |
| #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* GRR 970116 */ |
| /* Legacy API that weighted the filter metric by the number of times it had been |
| * used before. |
| */ |
| #ifdef PNG_FLOATING_POINT_SUPPORTED |
| PNG_FUNCTION(void,PNGAPI |
| png_set_filter_heuristics,(png_structrp png_ptr, int heuristic_method, |
| int num_weights, png_const_doublep filter_weights, |
| png_const_doublep filter_costs),PNG_DEPRECATED) |
| { |
| png_app_warning(png_ptr, "weighted filter heuristics not implemented"); |
| PNG_UNUSED(heuristic_method) |
| PNG_UNUSED(num_weights) |
| PNG_UNUSED(filter_weights) |
| PNG_UNUSED(filter_costs) |
| } |
| #endif /* FLOATING_POINT */ |
| |
| #ifdef PNG_FIXED_POINT_SUPPORTED |
| PNG_FUNCTION(void,PNGAPI |
| png_set_filter_heuristics_fixed,(png_structrp png_ptr, int heuristic_method, |
| int num_weights, png_const_fixed_point_p filter_weights, |
| png_const_fixed_point_p filter_costs),PNG_DEPRECATED) |
| { |
| png_app_warning(png_ptr, "weighted filter heuristics not implemented"); |
| PNG_UNUSED(heuristic_method) |
| PNG_UNUSED(num_weights) |
| PNG_UNUSED(filter_weights) |
| PNG_UNUSED(filter_costs) |
| } |
| #endif /* FIXED_POINT */ |
| #endif /* WRITE_WEIGHTED_FILTER */ |
| |
| #ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED |
| void PNGAPI |
| png_set_compression_level(png_structrp png_ptr, int level) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_compression_level"); |
| |
| if (ps != NULL) |
| ps->zlib_level = level; |
| } |
| |
| void PNGAPI |
| png_set_compression_mem_level(png_structrp png_ptr, int mem_level) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_compression_mem_level"); |
| |
| if (ps != NULL) |
| ps->zlib_mem_level = mem_level; |
| } |
| |
| void PNGAPI |
| png_set_compression_strategy(png_structrp png_ptr, int strategy) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_compression_strategy"); |
| |
| if (ps != NULL) |
| ps->zlib_strategy = strategy; |
| } |
| |
| /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a |
| * smaller value of window_bits if it can do so safely. |
| */ |
| void PNGAPI |
| png_set_compression_window_bits(png_structrp png_ptr, int window_bits) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| if (ps != NULL) |
| { |
| /* Prior to 1.6.0 this would warn but then set the window_bits value. This |
| * meant that negative window bits values could be selected that would |
| * cause libpng to write a non-standard PNG file with raw deflate or gzip |
| * compressed IDAT or ancillary chunks. Such files can be read and there |
| * is no warning on read, so this seems like a very bad idea. |
| */ |
| if (window_bits > 15) |
| { |
| png_app_warning(png_ptr, |
| "Only compression windows <= 32k supported by PNG"); |
| window_bits = 15; |
| } |
| |
| else if (window_bits < 8) |
| { |
| png_app_warning(png_ptr, |
| "Only compression windows >= 256 supported by PNG"); |
| window_bits = 8; |
| } |
| |
| ps->zlib_window_bits = window_bits; |
| } |
| } |
| |
| void PNGAPI |
| png_set_compression_method(png_structrp png_ptr, int method) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_compression_method"); |
| |
| if (ps != NULL) |
| { |
| /* This used to just warn, this seems unhelpful and might result in bogus |
| * PNG files if zlib starts accepting other methods. |
| */ |
| if (method == 8) |
| ps->zlib_method = method; |
| |
| else |
| png_app_error(png_ptr, |
| "Only compression method 8 is supported by PNG"); |
| } |
| } |
| #endif /* WRITE_CUSTOMIZE_COMPRESSION */ |
| |
| /* The following were added to libpng-1.5.4 */ |
| #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED |
| void PNGAPI |
| png_set_text_compression_level(png_structrp png_ptr, int level) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_text_compression_level"); |
| |
| if (ps != NULL) |
| ps->zlib_text_level = level; |
| } |
| |
| void PNGAPI |
| png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_text_compression_mem_level"); |
| |
| if (ps != NULL) |
| ps->zlib_text_mem_level = mem_level; |
| } |
| |
| void PNGAPI |
| png_set_text_compression_strategy(png_structrp png_ptr, int strategy) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_text_compression_strategy"); |
| |
| if (ps != NULL) |
| ps->zlib_text_strategy = strategy; |
| } |
| |
| /* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a |
| * smaller value of window_bits if it can do so safely. |
| */ |
| void PNGAPI |
| png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| if (ps != NULL) |
| { |
| if (window_bits > 15) |
| { |
| png_app_warning(png_ptr, |
| "Only compression windows <= 32k supported by PNG"); |
| window_bits = 15; |
| } |
| |
| else if (window_bits < 8) |
| { |
| png_app_error(png_ptr, |
| "Only compression windows >= 256 supported by PNG"); |
| window_bits = 8; |
| } |
| |
| ps->zlib_text_window_bits = window_bits; |
| } |
| } |
| |
| void PNGAPI |
| png_set_text_compression_method(png_structrp png_ptr, int method) |
| { |
| png_zlib_statep ps = png_get_zlib_state(png_ptr); |
| |
| png_debug(1, "in png_set_text_compression_method"); |
| |
| if (ps != NULL) |
| { |
| if (method == 8) |
| ps->zlib_text_method = method; |
| |
| else |
| png_app_error(png_ptr, |
| "Only compression method 8 is supported by PNG"); |
| |
| } |
| } |
| #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */ |
| /* end of API added to libpng-1.5.4 */ |
| |
| #endif /* WRITE */ |