0,0 → 1,3023 |
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/* pngwutil.c - utilities to write a PNG file |
* |
* Last changed in libpng 1.6.2 [April 25, 2013] |
* Copyright (c) 1998-2013 Glenn Randers-Pehrson |
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) |
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) |
* |
* This code is released under the libpng license. |
* For conditions of distribution and use, see the disclaimer |
* and license in png.h |
*/ |
|
#include "pngpriv.h" |
|
#ifdef PNG_WRITE_SUPPORTED |
|
#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED |
/* Place a 32-bit number into a buffer in PNG byte order. We work |
* with unsigned numbers for convenience, although one supported |
* ancillary chunk uses signed (two's complement) numbers. |
*/ |
void PNGAPI |
png_save_uint_32(png_bytep buf, png_uint_32 i) |
{ |
buf[0] = (png_byte)((i >> 24) & 0xff); |
buf[1] = (png_byte)((i >> 16) & 0xff); |
buf[2] = (png_byte)((i >> 8) & 0xff); |
buf[3] = (png_byte)(i & 0xff); |
} |
|
/* Place a 16-bit number into a buffer in PNG byte order. |
* The parameter is declared unsigned int, not png_uint_16, |
* just to avoid potential problems on pre-ANSI C compilers. |
*/ |
void PNGAPI |
png_save_uint_16(png_bytep buf, unsigned int i) |
{ |
buf[0] = (png_byte)((i >> 8) & 0xff); |
buf[1] = (png_byte)(i & 0xff); |
} |
#endif |
|
/* Simple function to write the signature. If we have already written |
* the magic bytes of the signature, or more likely, the PNG stream is |
* being embedded into another stream and doesn't need its own signature, |
* we should call png_set_sig_bytes() to tell libpng how many of the |
* bytes have already been written. |
*/ |
void PNGAPI |
png_write_sig(png_structrp png_ptr) |
{ |
png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; |
|
#ifdef PNG_IO_STATE_SUPPORTED |
/* Inform the I/O callback that the signature is being written */ |
png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE; |
#endif |
|
/* Write the rest of the 8 byte signature */ |
png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes], |
(png_size_t)(8 - png_ptr->sig_bytes)); |
|
if (png_ptr->sig_bytes < 3) |
png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; |
} |
|
/* Write the start of a PNG chunk. The type is the chunk type. |
* The total_length is the sum of the lengths of all the data you will be |
* passing in png_write_chunk_data(). |
*/ |
static void |
png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name, |
png_uint_32 length) |
{ |
png_byte buf[8]; |
|
#if defined(PNG_DEBUG) && (PNG_DEBUG > 0) |
PNG_CSTRING_FROM_CHUNK(buf, chunk_name); |
png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length); |
#endif |
|
if (png_ptr == NULL) |
return; |
|
#ifdef PNG_IO_STATE_SUPPORTED |
/* Inform the I/O callback that the chunk header is being written. |
* PNG_IO_CHUNK_HDR requires a single I/O call. |
*/ |
png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR; |
#endif |
|
/* Write the length and the chunk name */ |
png_save_uint_32(buf, length); |
png_save_uint_32(buf + 4, chunk_name); |
png_write_data(png_ptr, buf, 8); |
|
/* Put the chunk name into png_ptr->chunk_name */ |
png_ptr->chunk_name = chunk_name; |
|
/* Reset the crc and run it over the chunk name */ |
png_reset_crc(png_ptr); |
|
png_calculate_crc(png_ptr, buf + 4, 4); |
|
#ifdef PNG_IO_STATE_SUPPORTED |
/* Inform the I/O callback that chunk data will (possibly) be written. |
* PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls. |
*/ |
png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA; |
#endif |
} |
|
void PNGAPI |
png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string, |
png_uint_32 length) |
{ |
png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length); |
} |
|
/* Write the data of a PNG chunk started with png_write_chunk_header(). |
* Note that multiple calls to this function are allowed, and that the |
* sum of the lengths from these calls *must* add up to the total_length |
* given to png_write_chunk_header(). |
*/ |
void PNGAPI |
png_write_chunk_data(png_structrp png_ptr, png_const_bytep data, |
png_size_t length) |
{ |
/* Write the data, and run the CRC over it */ |
if (png_ptr == NULL) |
return; |
|
if (data != NULL && length > 0) |
{ |
png_write_data(png_ptr, data, length); |
|
/* Update the CRC after writing the data, |
* in case that the user I/O routine alters it. |
*/ |
png_calculate_crc(png_ptr, data, length); |
} |
} |
|
/* Finish a chunk started with png_write_chunk_header(). */ |
void PNGAPI |
png_write_chunk_end(png_structrp png_ptr) |
{ |
png_byte buf[4]; |
|
if (png_ptr == NULL) return; |
|
#ifdef PNG_IO_STATE_SUPPORTED |
/* Inform the I/O callback that the chunk CRC is being written. |
* PNG_IO_CHUNK_CRC requires a single I/O function call. |
*/ |
png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC; |
#endif |
|
/* Write the crc in a single operation */ |
png_save_uint_32(buf, png_ptr->crc); |
|
png_write_data(png_ptr, buf, (png_size_t)4); |
} |
|
/* Write a PNG chunk all at once. The type is an array of ASCII characters |
* representing the chunk name. The array must be at least 4 bytes in |
* length, and does not need to be null terminated. To be safe, pass the |
* pre-defined chunk names here, and if you need a new one, define it |
* where the others are defined. The length is the length of the data. |
* All the data must be present. If that is not possible, use the |
* png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end() |
* functions instead. |
*/ |
static void |
png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name, |
png_const_bytep data, png_size_t length) |
{ |
if (png_ptr == NULL) |
return; |
|
/* On 64 bit architectures 'length' may not fit in a png_uint_32. */ |
if (length > PNG_UINT_31_MAX) |
png_error(png_ptr, "length exceeds PNG maxima"); |
|
png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length); |
png_write_chunk_data(png_ptr, data, length); |
png_write_chunk_end(png_ptr); |
} |
|
/* This is the API that calls the internal function above. */ |
void PNGAPI |
png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string, |
png_const_bytep data, png_size_t length) |
{ |
png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data, |
length); |
} |
|
/* This is used below to find the size of an image to pass to png_deflate_claim, |
* so it only needs to be accurate if the size is less than 16384 bytes (the |
* point at which a lower LZ window size can be used.) |
*/ |
static png_alloc_size_t |
png_image_size(png_structrp png_ptr) |
{ |
/* Only return sizes up to the maximum of a png_uint_32, do this by limiting |
* the width and height used to 15 bits. |
*/ |
png_uint_32 h = png_ptr->height; |
|
if (png_ptr->rowbytes < 32768 && h < 32768) |
{ |
if (png_ptr->interlaced) |
{ |
/* Interlacing makes the image larger because of the replication of |
* both the filter byte and the padding to a byte boundary. |
*/ |
png_uint_32 w = png_ptr->width; |
unsigned int pd = png_ptr->pixel_depth; |
png_alloc_size_t cb_base; |
int pass; |
|
for (cb_base=0, pass=0; pass<=6; ++pass) |
{ |
png_uint_32 pw = PNG_PASS_COLS(w, pass); |
|
if (pw > 0) |
cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass); |
} |
|
return cb_base; |
} |
|
else |
return (png_ptr->rowbytes+1) * h; |
} |
|
else |
return 0xffffffffU; |
} |
|
#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
/* This is the code to hack the first two bytes of the deflate stream (the |
* deflate header) to correct the windowBits value to match the actual data |
* size. Note that the second argument is the *uncompressed* size but the |
* first argument is the *compressed* data (and it must be deflate |
* compressed.) |
*/ |
static void |
optimize_cmf(png_bytep data, png_alloc_size_t data_size) |
{ |
/* Optimize the CMF field in the zlib stream. The resultant zlib stream is |
* still compliant to the stream specification. |
*/ |
if (data_size <= 16384) /* else windowBits must be 15 */ |
{ |
unsigned int z_cmf = data[0]; /* zlib compression method and flags */ |
|
if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70) |
{ |
unsigned int z_cinfo; |
unsigned int half_z_window_size; |
|
z_cinfo = z_cmf >> 4; |
half_z_window_size = 1U << (z_cinfo + 7); |
|
if (data_size <= half_z_window_size) /* else no change */ |
{ |
unsigned int tmp; |
|
do |
{ |
half_z_window_size >>= 1; |
--z_cinfo; |
} |
while (z_cinfo > 0 && data_size <= half_z_window_size); |
|
z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4); |
|
data[0] = (png_byte)z_cmf; |
tmp = data[1] & 0xe0; |
tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f; |
data[1] = (png_byte)tmp; |
} |
} |
} |
} |
#else |
# define optimize_cmf(dp,dl) ((void)0) |
#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */ |
|
/* Initialize the compressor for the appropriate type of compression. */ |
static int |
png_deflate_claim(png_structrp png_ptr, png_uint_32 owner, |
png_alloc_size_t data_size) |
{ |
if (png_ptr->zowner != 0) |
{ |
char msg[64]; |
|
PNG_STRING_FROM_CHUNK(msg, owner); |
msg[4] = ':'; |
msg[5] = ' '; |
PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner); |
/* So the message that results is "<chunk> using zstream"; this is an |
* internal error, but is very useful for debugging. i18n requirements |
* are minimal. |
*/ |
(void)png_safecat(msg, (sizeof msg), 10, " using zstream"); |
# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC |
png_warning(png_ptr, msg); |
|
/* Attempt sane error recovery */ |
if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */ |
{ |
png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT"); |
return Z_STREAM_ERROR; |
} |
|
png_ptr->zowner = 0; |
# else |
png_error(png_ptr, msg); |
# endif |
} |
|
{ |
int level = png_ptr->zlib_level; |
int method = png_ptr->zlib_method; |
int windowBits = png_ptr->zlib_window_bits; |
int memLevel = png_ptr->zlib_mem_level; |
int strategy; /* set below */ |
int ret; /* zlib return code */ |
|
if (owner == png_IDAT) |
{ |
if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) |
strategy = png_ptr->zlib_strategy; |
|
else if (png_ptr->do_filter != PNG_FILTER_NONE) |
strategy = PNG_Z_DEFAULT_STRATEGY; |
|
else |
strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY; |
} |
|
else |
{ |
# ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED |
level = png_ptr->zlib_text_level; |
method = png_ptr->zlib_text_method; |
windowBits = png_ptr->zlib_text_window_bits; |
memLevel = png_ptr->zlib_text_mem_level; |
strategy = png_ptr->zlib_text_strategy; |
# else |
/* If customization is not supported the values all come from the |
* IDAT values except for the strategy, which is fixed to the |
* default. (This is the pre-1.6.0 behavior too, although it was |
* implemented in a very different way.) |
*/ |
strategy = Z_DEFAULT_STRATEGY; |
# endif |
} |
|
/* Adjust 'windowBits' down if larger than 'data_size'; to stop this |
* happening just pass 32768 as the data_size parameter. Notice that zlib |
* requires an extra 262 bytes in the window in addition to the data to be |
* able to see the whole of the data, so if data_size+262 takes us to the |
* next windowBits size we need to fix up the value later. (Because even |
* though deflate needs the extra window, inflate does not!) |
*/ |
if (data_size <= 16384) |
{ |
/* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to |
* work round a Microsoft Visual C misbehavior which, contrary to C-90, |
* widens the result of the following shift to 64-bits if (and, |
* apparently, only if) it is used in a test. |
*/ |
unsigned int half_window_size = 1U << (windowBits-1); |
|
while (data_size + 262 <= half_window_size) |
{ |
half_window_size >>= 1; |
--windowBits; |
} |
} |
|
/* Check against the previous initialized values, if any. */ |
if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) && |
(png_ptr->zlib_set_level != level || |
png_ptr->zlib_set_method != method || |
png_ptr->zlib_set_window_bits != windowBits || |
png_ptr->zlib_set_mem_level != memLevel || |
png_ptr->zlib_set_strategy != strategy)) |
{ |
if (deflateEnd(&png_ptr->zstream) != Z_OK) |
png_warning(png_ptr, "deflateEnd failed (ignored)"); |
|
png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED; |
} |
|
/* For safety clear out the input and output pointers (currently zlib |
* doesn't use them on Init, but it might in the future). |
*/ |
png_ptr->zstream.next_in = NULL; |
png_ptr->zstream.avail_in = 0; |
png_ptr->zstream.next_out = NULL; |
png_ptr->zstream.avail_out = 0; |
|
/* Now initialize if required, setting the new parameters, otherwise just |
* to a simple reset to the previous parameters. |
*/ |
if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) |
ret = deflateReset(&png_ptr->zstream); |
|
else |
{ |
ret = deflateInit2(&png_ptr->zstream, level, method, windowBits, |
memLevel, strategy); |
|
if (ret == Z_OK) |
png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; |
} |
|
/* The return code is from either deflateReset or deflateInit2; they have |
* pretty much the same set of error codes. |
*/ |
if (ret == Z_OK) |
png_ptr->zowner = owner; |
|
else |
png_zstream_error(png_ptr, ret); |
|
return ret; |
} |
} |
|
/* Clean up (or trim) a linked list of compression buffers. */ |
void /* PRIVATE */ |
png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp) |
{ |
png_compression_bufferp list = *listp; |
|
if (list != NULL) |
{ |
*listp = NULL; |
|
do |
{ |
png_compression_bufferp next = list->next; |
|
png_free(png_ptr, list); |
list = next; |
} |
while (list != NULL); |
} |
} |
|
#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED |
/* This pair of functions encapsulates the operation of (a) compressing a |
* text string, and (b) issuing it later as a series of chunk data writes. |
* The compression_state structure is shared context for these functions |
* set up by the caller to allow access to the relevant local variables. |
* |
* compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size |
* temporary buffers. From 1.6.0 it is retained in png_struct so that it will |
* be correctly freed in the event of a write error (previous implementations |
* just leaked memory.) |
*/ |
typedef struct |
{ |
png_const_bytep input; /* The uncompressed input data */ |
png_alloc_size_t input_len; /* Its length */ |
png_uint_32 output_len; /* Final compressed length */ |
png_byte output[1024]; /* First block of output */ |
} compression_state; |
|
static void |
png_text_compress_init(compression_state *comp, png_const_bytep input, |
png_alloc_size_t input_len) |
{ |
comp->input = input; |
comp->input_len = input_len; |
comp->output_len = 0; |
} |
|
/* Compress the data in the compression state input */ |
static int |
png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name, |
compression_state *comp, png_uint_32 prefix_len) |
{ |
int ret; |
|
/* To find the length of the output it is necessary to first compress the |
* input, the result is buffered rather than using the two-pass algorithm |
* that is used on the inflate side; deflate is assumed to be slower and a |
* PNG writer is assumed to have more memory available than a PNG reader. |
* |
* IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an |
* upper limit on the output size, but it is always bigger than the input |
* size so it is likely to be more efficient to use this linked-list |
* approach. |
*/ |
ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len); |
|
if (ret != Z_OK) |
return ret; |
|
/* Set up the compression buffers, we need a loop here to avoid overflowing a |
* uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited |
* by the output buffer size, so there is no need to check that. Since this |
* is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits |
* in size. |
*/ |
{ |
png_compression_bufferp *end = &png_ptr->zbuffer_list; |
png_alloc_size_t input_len = comp->input_len; /* may be zero! */ |
png_uint_32 output_len; |
|
/* zlib updates these for us: */ |
png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input); |
png_ptr->zstream.avail_in = 0; /* Set below */ |
png_ptr->zstream.next_out = comp->output; |
png_ptr->zstream.avail_out = (sizeof comp->output); |
|
output_len = png_ptr->zstream.avail_out; |
|
do |
{ |
uInt avail_in = ZLIB_IO_MAX; |
|
if (avail_in > input_len) |
avail_in = (uInt)input_len; |
|
input_len -= avail_in; |
|
png_ptr->zstream.avail_in = avail_in; |
|
if (png_ptr->zstream.avail_out == 0) |
{ |
png_compression_buffer *next; |
|
/* Chunk data is limited to 2^31 bytes in length, so the prefix |
* length must be counted here. |
*/ |
if (output_len + prefix_len > PNG_UINT_31_MAX) |
{ |
ret = Z_MEM_ERROR; |
break; |
} |
|
/* Need a new (malloc'ed) buffer, but there may be one present |
* already. |
*/ |
next = *end; |
if (next == NULL) |
{ |
next = png_voidcast(png_compression_bufferp, png_malloc_base |
(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr))); |
|
if (next == NULL) |
{ |
ret = Z_MEM_ERROR; |
break; |
} |
|
/* Link in this buffer (so that it will be freed later) */ |
next->next = NULL; |
*end = next; |
} |
|
png_ptr->zstream.next_out = next->output; |
png_ptr->zstream.avail_out = png_ptr->zbuffer_size; |
output_len += png_ptr->zstream.avail_out; |
|
/* Move 'end' to the next buffer pointer. */ |
end = &next->next; |
} |
|
/* Compress the data */ |
ret = deflate(&png_ptr->zstream, |
input_len > 0 ? Z_NO_FLUSH : Z_FINISH); |
|
/* Claw back input data that was not consumed (because avail_in is |
* reset above every time round the loop). |
*/ |
input_len += png_ptr->zstream.avail_in; |
png_ptr->zstream.avail_in = 0; /* safety */ |
} |
while (ret == Z_OK); |
|
/* There may be some space left in the last output buffer, this needs to |
* be subtracted from output_len. |
*/ |
output_len -= png_ptr->zstream.avail_out; |
png_ptr->zstream.avail_out = 0; /* safety */ |
comp->output_len = output_len; |
|
/* Now double check the output length, put in a custom message if it is |
* too long. Otherwise ensure the z_stream::msg pointer is set to |
* something. |
*/ |
if (output_len + prefix_len >= PNG_UINT_31_MAX) |
{ |
png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long"); |
ret = Z_MEM_ERROR; |
} |
|
else |
png_zstream_error(png_ptr, ret); |
|
/* Reset zlib for another zTXt/iTXt or image data */ |
png_ptr->zowner = 0; |
|
/* The only success case is Z_STREAM_END, input_len must be 0, if not this |
* is an internal error. |
*/ |
if (ret == Z_STREAM_END && input_len == 0) |
{ |
/* Fix up the deflate header, if required */ |
optimize_cmf(comp->output, comp->input_len); |
|
/* But Z_OK is returned, not Z_STREAM_END; this allows the claim |
* function above to return Z_STREAM_END on an error (though it never |
* does in the current versions of zlib.) |
*/ |
return Z_OK; |
} |
|
else |
return ret; |
} |
} |
|
/* Ship the compressed text out via chunk writes */ |
static void |
png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp) |
{ |
png_uint_32 output_len = comp->output_len; |
png_const_bytep output = comp->output; |
png_uint_32 avail = (sizeof comp->output); |
png_compression_buffer *next = png_ptr->zbuffer_list; |
|
for (;;) |
{ |
if (avail > output_len) |
avail = output_len; |
|
png_write_chunk_data(png_ptr, output, avail); |
|
output_len -= avail; |
|
if (output_len == 0 || next == NULL) |
break; |
|
avail = png_ptr->zbuffer_size; |
output = next->output; |
next = next->next; |
} |
|
/* This is an internal error; 'next' must have been NULL! */ |
if (output_len > 0) |
png_error(png_ptr, "error writing ancillary chunked compressed data"); |
} |
#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */ |
|
#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \ |
defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED) |
/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification, |
* and if invalid, correct the keyword rather than discarding the entire |
* chunk. The PNG 1.0 specification requires keywords 1-79 characters in |
* length, forbids leading or trailing whitespace, multiple internal spaces, |
* and the non-break space (0x80) from ISO 8859-1. Returns keyword length. |
* |
* The 'new_key' buffer must be 80 characters in size (for the keyword plus a |
* trailing '\0'). If this routine returns 0 then there was no keyword, or a |
* valid one could not be generated, and the caller must png_error. |
*/ |
static png_uint_32 |
png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key) |
{ |
png_const_charp orig_key = key; |
png_uint_32 key_len = 0; |
int bad_character = 0; |
int space = 1; |
|
png_debug(1, "in png_check_keyword"); |
|
if (key == NULL) |
{ |
*new_key = 0; |
return 0; |
} |
|
while (*key && key_len < 79) |
{ |
png_byte ch = (png_byte)(0xff & *key++); |
|
if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/)) |
*new_key++ = ch, ++key_len, space = 0; |
|
else if (!space) |
{ |
/* A space or an invalid character when one wasn't seen immediately |
* before; output just a space. |
*/ |
*new_key++ = 32, ++key_len, space = 1; |
|
/* If the character was not a space then it is invalid. */ |
if (ch != 32) |
bad_character = ch; |
} |
|
else if (!bad_character) |
bad_character = ch; /* just skip it, record the first error */ |
} |
|
if (key_len > 0 && space) /* trailing space */ |
{ |
--key_len, --new_key; |
if (!bad_character) |
bad_character = 32; |
} |
|
/* Terminate the keyword */ |
*new_key = 0; |
|
if (key_len == 0) |
return 0; |
|
/* Try to only output one warning per keyword: */ |
if (*key) /* keyword too long */ |
png_warning(png_ptr, "keyword truncated"); |
|
else if (bad_character) |
{ |
PNG_WARNING_PARAMETERS(p) |
|
png_warning_parameter(p, 1, orig_key); |
png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character); |
|
png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'"); |
} |
|
return key_len; |
} |
#endif |
|
/* Write the IHDR chunk, and update the png_struct with the necessary |
* information. Note that the rest of this code depends upon this |
* information being correct. |
*/ |
void /* PRIVATE */ |
png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height, |
int bit_depth, int color_type, int compression_type, int filter_type, |
int interlace_type) |
{ |
png_byte buf[13]; /* Buffer to store the IHDR info */ |
|
png_debug(1, "in png_write_IHDR"); |
|
/* Check that we have valid input data from the application info */ |
switch (color_type) |
{ |
case PNG_COLOR_TYPE_GRAY: |
switch (bit_depth) |
{ |
case 1: |
case 2: |
case 4: |
case 8: |
#ifdef PNG_WRITE_16BIT_SUPPORTED |
case 16: |
#endif |
png_ptr->channels = 1; break; |
|
default: |
png_error(png_ptr, |
"Invalid bit depth for grayscale image"); |
} |
break; |
|
case PNG_COLOR_TYPE_RGB: |
#ifdef PNG_WRITE_16BIT_SUPPORTED |
if (bit_depth != 8 && bit_depth != 16) |
#else |
if (bit_depth != 8) |
#endif |
png_error(png_ptr, "Invalid bit depth for RGB image"); |
|
png_ptr->channels = 3; |
break; |
|
case PNG_COLOR_TYPE_PALETTE: |
switch (bit_depth) |
{ |
case 1: |
case 2: |
case 4: |
case 8: |
png_ptr->channels = 1; |
break; |
|
default: |
png_error(png_ptr, "Invalid bit depth for paletted image"); |
} |
break; |
|
case PNG_COLOR_TYPE_GRAY_ALPHA: |
if (bit_depth != 8 && bit_depth != 16) |
png_error(png_ptr, "Invalid bit depth for grayscale+alpha image"); |
|
png_ptr->channels = 2; |
break; |
|
case PNG_COLOR_TYPE_RGB_ALPHA: |
#ifdef PNG_WRITE_16BIT_SUPPORTED |
if (bit_depth != 8 && bit_depth != 16) |
#else |
if (bit_depth != 8) |
#endif |
png_error(png_ptr, "Invalid bit depth for RGBA image"); |
|
png_ptr->channels = 4; |
break; |
|
default: |
png_error(png_ptr, "Invalid image color type specified"); |
} |
|
if (compression_type != PNG_COMPRESSION_TYPE_BASE) |
{ |
png_warning(png_ptr, "Invalid compression type specified"); |
compression_type = PNG_COMPRESSION_TYPE_BASE; |
} |
|
/* Write filter_method 64 (intrapixel differencing) only if |
* 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and |
* 2. Libpng did not write a PNG signature (this filter_method is only |
* used in PNG datastreams that are embedded in MNG datastreams) and |
* 3. The application called png_permit_mng_features with a mask that |
* included PNG_FLAG_MNG_FILTER_64 and |
* 4. The filter_method is 64 and |
* 5. The color_type is RGB or RGBA |
*/ |
if ( |
#ifdef PNG_MNG_FEATURES_SUPPORTED |
!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) && |
((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) && |
(color_type == PNG_COLOR_TYPE_RGB || |
color_type == PNG_COLOR_TYPE_RGB_ALPHA) && |
(filter_type == PNG_INTRAPIXEL_DIFFERENCING)) && |
#endif |
filter_type != PNG_FILTER_TYPE_BASE) |
{ |
png_warning(png_ptr, "Invalid filter type specified"); |
filter_type = PNG_FILTER_TYPE_BASE; |
} |
|
#ifdef PNG_WRITE_INTERLACING_SUPPORTED |
if (interlace_type != PNG_INTERLACE_NONE && |
interlace_type != PNG_INTERLACE_ADAM7) |
{ |
png_warning(png_ptr, "Invalid interlace type specified"); |
interlace_type = PNG_INTERLACE_ADAM7; |
} |
#else |
interlace_type=PNG_INTERLACE_NONE; |
#endif |
|
/* Save the relevent information */ |
png_ptr->bit_depth = (png_byte)bit_depth; |
png_ptr->color_type = (png_byte)color_type; |
png_ptr->interlaced = (png_byte)interlace_type; |
#ifdef PNG_MNG_FEATURES_SUPPORTED |
png_ptr->filter_type = (png_byte)filter_type; |
#endif |
png_ptr->compression_type = (png_byte)compression_type; |
png_ptr->width = width; |
png_ptr->height = height; |
|
png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels); |
png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width); |
/* Set the usr info, so any transformations can modify it */ |
png_ptr->usr_width = png_ptr->width; |
png_ptr->usr_bit_depth = png_ptr->bit_depth; |
png_ptr->usr_channels = png_ptr->channels; |
|
/* Pack the header information into the buffer */ |
png_save_uint_32(buf, width); |
png_save_uint_32(buf + 4, height); |
buf[8] = (png_byte)bit_depth; |
buf[9] = (png_byte)color_type; |
buf[10] = (png_byte)compression_type; |
buf[11] = (png_byte)filter_type; |
buf[12] = (png_byte)interlace_type; |
|
/* Write the chunk */ |
png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13); |
|
if (!(png_ptr->do_filter)) |
{ |
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE || |
png_ptr->bit_depth < 8) |
png_ptr->do_filter = PNG_FILTER_NONE; |
|
else |
png_ptr->do_filter = PNG_ALL_FILTERS; |
} |
|
png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */ |
} |
|
/* Write the palette. We are careful not to trust png_color to be in the |
* correct order for PNG, so people can redefine it to any convenient |
* structure. |
*/ |
void /* PRIVATE */ |
png_write_PLTE(png_structrp png_ptr, png_const_colorp palette, |
png_uint_32 num_pal) |
{ |
png_uint_32 i; |
png_const_colorp pal_ptr; |
png_byte buf[3]; |
|
png_debug(1, "in png_write_PLTE"); |
|
if (( |
#ifdef PNG_MNG_FEATURES_SUPPORTED |
!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) && |
#endif |
num_pal == 0) || num_pal > 256) |
{ |
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
{ |
png_error(png_ptr, "Invalid number of colors in palette"); |
} |
|
else |
{ |
png_warning(png_ptr, "Invalid number of colors in palette"); |
return; |
} |
} |
|
if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR)) |
{ |
png_warning(png_ptr, |
"Ignoring request to write a PLTE chunk in grayscale PNG"); |
|
return; |
} |
|
png_ptr->num_palette = (png_uint_16)num_pal; |
png_debug1(3, "num_palette = %d", png_ptr->num_palette); |
|
png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3)); |
#ifdef PNG_POINTER_INDEXING_SUPPORTED |
|
for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++) |
{ |
buf[0] = pal_ptr->red; |
buf[1] = pal_ptr->green; |
buf[2] = pal_ptr->blue; |
png_write_chunk_data(png_ptr, buf, (png_size_t)3); |
} |
|
#else |
/* This is a little slower but some buggy compilers need to do this |
* instead |
*/ |
pal_ptr=palette; |
|
for (i = 0; i < num_pal; i++) |
{ |
buf[0] = pal_ptr[i].red; |
buf[1] = pal_ptr[i].green; |
buf[2] = pal_ptr[i].blue; |
png_write_chunk_data(png_ptr, buf, (png_size_t)3); |
} |
|
#endif |
png_write_chunk_end(png_ptr); |
png_ptr->mode |= PNG_HAVE_PLTE; |
} |
|
/* This is similar to png_text_compress, above, except that it does not require |
* all of the data at once and, instead of buffering the compressed result, |
* writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out |
* because it calls the write interface. As a result it does its own error |
* reporting and does not return an error code. In the event of error it will |
* just call png_error. The input data length may exceed 32-bits. The 'flush' |
* parameter is exactly the same as that to deflate, with the following |
* meanings: |
* |
* Z_NO_FLUSH: normal incremental output of compressed data |
* Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush |
* Z_FINISH: this is the end of the input, do a Z_FINISH and clean up |
* |
* The routine manages the acquire and release of the png_ptr->zstream by |
* checking and (at the end) clearing png_ptr->zowner, it does some sanity |
* checks on the 'mode' flags while doing this. |
*/ |
void /* PRIVATE */ |
png_compress_IDAT(png_structrp png_ptr, png_const_bytep input, |
png_alloc_size_t input_len, int flush) |
{ |
if (png_ptr->zowner != png_IDAT) |
{ |
/* First time. Ensure we have a temporary buffer for compression and |
* trim the buffer list if it has more than one entry to free memory. |
* If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been |
* created at this point, but the check here is quick and safe. |
*/ |
if (png_ptr->zbuffer_list == NULL) |
{ |
png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp, |
png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr))); |
png_ptr->zbuffer_list->next = NULL; |
} |
|
else |
png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next); |
|
/* It is a terminal error if we can't claim the zstream. */ |
if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK) |
png_error(png_ptr, png_ptr->zstream.msg); |
|
/* The output state is maintained in png_ptr->zstream, so it must be |
* initialized here after the claim. |
*/ |
png_ptr->zstream.next_out = png_ptr->zbuffer_list->output; |
png_ptr->zstream.avail_out = png_ptr->zbuffer_size; |
} |
|
/* Now loop reading and writing until all the input is consumed or an error |
* terminates the operation. The _out values are maintained across calls to |
* this function, but the input must be reset each time. |
*/ |
png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); |
png_ptr->zstream.avail_in = 0; /* set below */ |
for (;;) |
{ |
int ret; |
|
/* INPUT: from the row data */ |
uInt avail = ZLIB_IO_MAX; |
|
if (avail > input_len) |
avail = (uInt)input_len; /* safe because of the check */ |
|
png_ptr->zstream.avail_in = avail; |
input_len -= avail; |
|
ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush); |
|
/* Include as-yet unconsumed input */ |
input_len += png_ptr->zstream.avail_in; |
png_ptr->zstream.avail_in = 0; |
|
/* OUTPUT: write complete IDAT chunks when avail_out drops to zero, note |
* that these two zstream fields are preserved across the calls, therefore |
* there is no need to set these up on entry to the loop. |
*/ |
if (png_ptr->zstream.avail_out == 0) |
{ |
png_bytep data = png_ptr->zbuffer_list->output; |
uInt size = png_ptr->zbuffer_size; |
|
/* Write an IDAT containing the data then reset the buffer. The |
* first IDAT may need deflate header optimization. |
*/ |
# ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
if (!(png_ptr->mode & PNG_HAVE_IDAT) && |
png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) |
optimize_cmf(data, png_image_size(png_ptr)); |
# endif |
|
png_write_complete_chunk(png_ptr, png_IDAT, data, size); |
png_ptr->mode |= PNG_HAVE_IDAT; |
|
png_ptr->zstream.next_out = data; |
png_ptr->zstream.avail_out = size; |
|
/* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with |
* the same flush parameter until it has finished output, for NO_FLUSH |
* it doesn't matter. |
*/ |
if (ret == Z_OK && flush != Z_NO_FLUSH) |
continue; |
} |
|
/* The order of these checks doesn't matter much; it just effect which |
* possible error might be detected if multiple things go wrong at once. |
*/ |
if (ret == Z_OK) /* most likely return code! */ |
{ |
/* If all the input has been consumed then just return. If Z_FINISH |
* was used as the flush parameter something has gone wrong if we get |
* here. |
*/ |
if (input_len == 0) |
{ |
if (flush == Z_FINISH) |
png_error(png_ptr, "Z_OK on Z_FINISH with output space"); |
|
return; |
} |
} |
|
else if (ret == Z_STREAM_END && flush == Z_FINISH) |
{ |
/* This is the end of the IDAT data; any pending output must be |
* flushed. For small PNG files we may still be at the beginning. |
*/ |
png_bytep data = png_ptr->zbuffer_list->output; |
uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out; |
|
# ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
if (!(png_ptr->mode & PNG_HAVE_IDAT) && |
png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) |
optimize_cmf(data, png_image_size(png_ptr)); |
# endif |
|
png_write_complete_chunk(png_ptr, png_IDAT, data, size); |
png_ptr->zstream.avail_out = 0; |
png_ptr->zstream.next_out = NULL; |
png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT; |
|
png_ptr->zowner = 0; /* Release the stream */ |
return; |
} |
|
else |
{ |
/* This is an error condition. */ |
png_zstream_error(png_ptr, ret); |
png_error(png_ptr, png_ptr->zstream.msg); |
} |
} |
} |
|
/* Write an IEND chunk */ |
void /* PRIVATE */ |
png_write_IEND(png_structrp png_ptr) |
{ |
png_debug(1, "in png_write_IEND"); |
|
png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0); |
png_ptr->mode |= PNG_HAVE_IEND; |
} |
|
#ifdef PNG_WRITE_gAMA_SUPPORTED |
/* Write a gAMA chunk */ |
void /* PRIVATE */ |
png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma) |
{ |
png_byte buf[4]; |
|
png_debug(1, "in png_write_gAMA"); |
|
/* file_gamma is saved in 1/100,000ths */ |
png_save_uint_32(buf, (png_uint_32)file_gamma); |
png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4); |
} |
#endif |
|
#ifdef PNG_WRITE_sRGB_SUPPORTED |
/* Write a sRGB chunk */ |
void /* PRIVATE */ |
png_write_sRGB(png_structrp png_ptr, int srgb_intent) |
{ |
png_byte buf[1]; |
|
png_debug(1, "in png_write_sRGB"); |
|
if (srgb_intent >= PNG_sRGB_INTENT_LAST) |
png_warning(png_ptr, |
"Invalid sRGB rendering intent specified"); |
|
buf[0]=(png_byte)srgb_intent; |
png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1); |
} |
#endif |
|
#ifdef PNG_WRITE_iCCP_SUPPORTED |
/* Write an iCCP chunk */ |
void /* PRIVATE */ |
png_write_iCCP(png_structrp png_ptr, png_const_charp name, |
png_const_bytep profile) |
{ |
png_uint_32 name_len; |
png_uint_32 profile_len; |
png_byte new_name[81]; /* 1 byte for the compression byte */ |
compression_state comp; |
|
png_debug(1, "in png_write_iCCP"); |
|
/* These are all internal problems: the profile should have been checked |
* before when it was stored. |
*/ |
if (profile == NULL) |
png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */ |
|
profile_len = png_get_uint_32(profile); |
|
if (profile_len < 132) |
png_error(png_ptr, "ICC profile too short"); |
|
if (profile_len & 0x03) |
png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)"); |
|
{ |
png_uint_32 embedded_profile_len = png_get_uint_32(profile); |
|
if (profile_len != embedded_profile_len) |
png_error(png_ptr, "Profile length does not match profile"); |
} |
|
name_len = png_check_keyword(png_ptr, name, new_name); |
|
if (name_len == 0) |
png_error(png_ptr, "iCCP: invalid keyword"); |
|
new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE; |
|
/* Make sure we include the NULL after the name and the compression type */ |
++name_len; |
|
png_text_compress_init(&comp, profile, profile_len); |
|
/* Allow for keyword terminator and compression byte */ |
if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK) |
png_error(png_ptr, png_ptr->zstream.msg); |
|
png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len); |
|
png_write_chunk_data(png_ptr, new_name, name_len); |
|
png_write_compressed_data_out(png_ptr, &comp); |
|
png_write_chunk_end(png_ptr); |
} |
#endif |
|
#ifdef PNG_WRITE_sPLT_SUPPORTED |
/* Write a sPLT chunk */ |
void /* PRIVATE */ |
png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette) |
{ |
png_uint_32 name_len; |
png_byte new_name[80]; |
png_byte entrybuf[10]; |
png_size_t entry_size = (spalette->depth == 8 ? 6 : 10); |
png_size_t palette_size = entry_size * spalette->nentries; |
png_sPLT_entryp ep; |
#ifndef PNG_POINTER_INDEXING_SUPPORTED |
int i; |
#endif |
|
png_debug(1, "in png_write_sPLT"); |
|
name_len = png_check_keyword(png_ptr, spalette->name, new_name); |
|
if (name_len == 0) |
png_error(png_ptr, "sPLT: invalid keyword"); |
|
/* Make sure we include the NULL after the name */ |
png_write_chunk_header(png_ptr, png_sPLT, |
(png_uint_32)(name_len + 2 + palette_size)); |
|
png_write_chunk_data(png_ptr, (png_bytep)new_name, |
(png_size_t)(name_len + 1)); |
|
png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1); |
|
/* Loop through each palette entry, writing appropriately */ |
#ifdef PNG_POINTER_INDEXING_SUPPORTED |
for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++) |
{ |
if (spalette->depth == 8) |
{ |
entrybuf[0] = (png_byte)ep->red; |
entrybuf[1] = (png_byte)ep->green; |
entrybuf[2] = (png_byte)ep->blue; |
entrybuf[3] = (png_byte)ep->alpha; |
png_save_uint_16(entrybuf + 4, ep->frequency); |
} |
|
else |
{ |
png_save_uint_16(entrybuf + 0, ep->red); |
png_save_uint_16(entrybuf + 2, ep->green); |
png_save_uint_16(entrybuf + 4, ep->blue); |
png_save_uint_16(entrybuf + 6, ep->alpha); |
png_save_uint_16(entrybuf + 8, ep->frequency); |
} |
|
png_write_chunk_data(png_ptr, entrybuf, entry_size); |
} |
#else |
ep=spalette->entries; |
for (i = 0; i>spalette->nentries; i++) |
{ |
if (spalette->depth == 8) |
{ |
entrybuf[0] = (png_byte)ep[i].red; |
entrybuf[1] = (png_byte)ep[i].green; |
entrybuf[2] = (png_byte)ep[i].blue; |
entrybuf[3] = (png_byte)ep[i].alpha; |
png_save_uint_16(entrybuf + 4, ep[i].frequency); |
} |
|
else |
{ |
png_save_uint_16(entrybuf + 0, ep[i].red); |
png_save_uint_16(entrybuf + 2, ep[i].green); |
png_save_uint_16(entrybuf + 4, ep[i].blue); |
png_save_uint_16(entrybuf + 6, ep[i].alpha); |
png_save_uint_16(entrybuf + 8, ep[i].frequency); |
} |
|
png_write_chunk_data(png_ptr, entrybuf, entry_size); |
} |
#endif |
|
png_write_chunk_end(png_ptr); |
} |
#endif |
|
#ifdef PNG_WRITE_sBIT_SUPPORTED |
/* Write the sBIT chunk */ |
void /* PRIVATE */ |
png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type) |
{ |
png_byte buf[4]; |
png_size_t size; |
|
png_debug(1, "in png_write_sBIT"); |
|
/* Make sure we don't depend upon the order of PNG_COLOR_8 */ |
if (color_type & PNG_COLOR_MASK_COLOR) |
{ |
png_byte maxbits; |
|
maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 : |
png_ptr->usr_bit_depth); |
|
if (sbit->red == 0 || sbit->red > maxbits || |
sbit->green == 0 || sbit->green > maxbits || |
sbit->blue == 0 || sbit->blue > maxbits) |
{ |
png_warning(png_ptr, "Invalid sBIT depth specified"); |
return; |
} |
|
buf[0] = sbit->red; |
buf[1] = sbit->green; |
buf[2] = sbit->blue; |
size = 3; |
} |
|
else |
{ |
if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth) |
{ |
png_warning(png_ptr, "Invalid sBIT depth specified"); |
return; |
} |
|
buf[0] = sbit->gray; |
size = 1; |
} |
|
if (color_type & PNG_COLOR_MASK_ALPHA) |
{ |
if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth) |
{ |
png_warning(png_ptr, "Invalid sBIT depth specified"); |
return; |
} |
|
buf[size++] = sbit->alpha; |
} |
|
png_write_complete_chunk(png_ptr, png_sBIT, buf, size); |
} |
#endif |
|
#ifdef PNG_WRITE_cHRM_SUPPORTED |
/* Write the cHRM chunk */ |
void /* PRIVATE */ |
png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy) |
{ |
png_byte buf[32]; |
|
png_debug(1, "in png_write_cHRM"); |
|
/* Each value is saved in 1/100,000ths */ |
png_save_int_32(buf, xy->whitex); |
png_save_int_32(buf + 4, xy->whitey); |
|
png_save_int_32(buf + 8, xy->redx); |
png_save_int_32(buf + 12, xy->redy); |
|
png_save_int_32(buf + 16, xy->greenx); |
png_save_int_32(buf + 20, xy->greeny); |
|
png_save_int_32(buf + 24, xy->bluex); |
png_save_int_32(buf + 28, xy->bluey); |
|
png_write_complete_chunk(png_ptr, png_cHRM, buf, 32); |
} |
#endif |
|
#ifdef PNG_WRITE_tRNS_SUPPORTED |
/* Write the tRNS chunk */ |
void /* PRIVATE */ |
png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha, |
png_const_color_16p tran, int num_trans, int color_type) |
{ |
png_byte buf[6]; |
|
png_debug(1, "in png_write_tRNS"); |
|
if (color_type == PNG_COLOR_TYPE_PALETTE) |
{ |
if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette) |
{ |
png_app_warning(png_ptr, |
"Invalid number of transparent colors specified"); |
return; |
} |
|
/* Write the chunk out as it is */ |
png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, |
(png_size_t)num_trans); |
} |
|
else if (color_type == PNG_COLOR_TYPE_GRAY) |
{ |
/* One 16 bit value */ |
if (tran->gray >= (1 << png_ptr->bit_depth)) |
{ |
png_app_warning(png_ptr, |
"Ignoring attempt to write tRNS chunk out-of-range for bit_depth"); |
|
return; |
} |
|
png_save_uint_16(buf, tran->gray); |
png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2); |
} |
|
else if (color_type == PNG_COLOR_TYPE_RGB) |
{ |
/* Three 16 bit values */ |
png_save_uint_16(buf, tran->red); |
png_save_uint_16(buf + 2, tran->green); |
png_save_uint_16(buf + 4, tran->blue); |
#ifdef PNG_WRITE_16BIT_SUPPORTED |
if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) |
#else |
if (buf[0] | buf[2] | buf[4]) |
#endif |
{ |
png_app_warning(png_ptr, |
"Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8"); |
return; |
} |
|
png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6); |
} |
|
else |
{ |
png_app_warning(png_ptr, "Can't write tRNS with an alpha channel"); |
} |
} |
#endif |
|
#ifdef PNG_WRITE_bKGD_SUPPORTED |
/* Write the background chunk */ |
void /* PRIVATE */ |
png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type) |
{ |
png_byte buf[6]; |
|
png_debug(1, "in png_write_bKGD"); |
|
if (color_type == PNG_COLOR_TYPE_PALETTE) |
{ |
if ( |
#ifdef PNG_MNG_FEATURES_SUPPORTED |
(png_ptr->num_palette || |
(!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) && |
#endif |
back->index >= png_ptr->num_palette) |
{ |
png_warning(png_ptr, "Invalid background palette index"); |
return; |
} |
|
buf[0] = back->index; |
png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1); |
} |
|
else if (color_type & PNG_COLOR_MASK_COLOR) |
{ |
png_save_uint_16(buf, back->red); |
png_save_uint_16(buf + 2, back->green); |
png_save_uint_16(buf + 4, back->blue); |
#ifdef PNG_WRITE_16BIT_SUPPORTED |
if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4])) |
#else |
if (buf[0] | buf[2] | buf[4]) |
#endif |
{ |
png_warning(png_ptr, |
"Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8"); |
|
return; |
} |
|
png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6); |
} |
|
else |
{ |
if (back->gray >= (1 << png_ptr->bit_depth)) |
{ |
png_warning(png_ptr, |
"Ignoring attempt to write bKGD chunk out-of-range for bit_depth"); |
|
return; |
} |
|
png_save_uint_16(buf, back->gray); |
png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2); |
} |
} |
#endif |
|
#ifdef PNG_WRITE_hIST_SUPPORTED |
/* Write the histogram */ |
void /* PRIVATE */ |
png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist) |
{ |
int i; |
png_byte buf[3]; |
|
png_debug(1, "in png_write_hIST"); |
|
if (num_hist > (int)png_ptr->num_palette) |
{ |
png_debug2(3, "num_hist = %d, num_palette = %d", num_hist, |
png_ptr->num_palette); |
|
png_warning(png_ptr, "Invalid number of histogram entries specified"); |
return; |
} |
|
png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2)); |
|
for (i = 0; i < num_hist; i++) |
{ |
png_save_uint_16(buf, hist[i]); |
png_write_chunk_data(png_ptr, buf, (png_size_t)2); |
} |
|
png_write_chunk_end(png_ptr); |
} |
#endif |
|
#ifdef PNG_WRITE_tEXt_SUPPORTED |
/* Write a tEXt chunk */ |
void /* PRIVATE */ |
png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, |
png_size_t text_len) |
{ |
png_uint_32 key_len; |
png_byte new_key[80]; |
|
png_debug(1, "in png_write_tEXt"); |
|
key_len = png_check_keyword(png_ptr, key, new_key); |
|
if (key_len == 0) |
png_error(png_ptr, "tEXt: invalid keyword"); |
|
if (text == NULL || *text == '\0') |
text_len = 0; |
|
else |
text_len = strlen(text); |
|
if (text_len > PNG_UINT_31_MAX - (key_len+1)) |
png_error(png_ptr, "tEXt: text too long"); |
|
/* Make sure we include the 0 after the key */ |
png_write_chunk_header(png_ptr, png_tEXt, |
(png_uint_32)/*checked above*/(key_len + text_len + 1)); |
/* |
* We leave it to the application to meet PNG-1.0 requirements on the |
* contents of the text. PNG-1.0 through PNG-1.2 discourage the use of |
* any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them. |
* The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. |
*/ |
png_write_chunk_data(png_ptr, new_key, key_len + 1); |
|
if (text_len) |
png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len); |
|
png_write_chunk_end(png_ptr); |
} |
#endif |
|
#ifdef PNG_WRITE_zTXt_SUPPORTED |
/* Write a compressed text chunk */ |
void /* PRIVATE */ |
png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, |
png_size_t text_len, int compression) |
{ |
png_uint_32 key_len; |
png_byte new_key[81]; |
compression_state comp; |
|
png_debug(1, "in png_write_zTXt"); |
PNG_UNUSED(text_len) /* Always use strlen */ |
|
if (compression == PNG_TEXT_COMPRESSION_NONE) |
{ |
png_write_tEXt(png_ptr, key, text, 0); |
return; |
} |
|
if (compression != PNG_TEXT_COMPRESSION_zTXt) |
png_error(png_ptr, "zTXt: invalid compression type"); |
|
key_len = png_check_keyword(png_ptr, key, new_key); |
|
if (key_len == 0) |
png_error(png_ptr, "zTXt: invalid keyword"); |
|
/* Add the compression method and 1 for the keyword separator. */ |
new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE; |
++key_len; |
|
/* Compute the compressed data; do it now for the length */ |
png_text_compress_init(&comp, (png_const_bytep)text, |
text == NULL ? 0 : strlen(text)); |
|
if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK) |
png_error(png_ptr, png_ptr->zstream.msg); |
|
/* Write start of chunk */ |
png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len); |
|
/* Write key */ |
png_write_chunk_data(png_ptr, new_key, key_len); |
|
/* Write the compressed data */ |
png_write_compressed_data_out(png_ptr, &comp); |
|
/* Close the chunk */ |
png_write_chunk_end(png_ptr); |
} |
#endif |
|
#ifdef PNG_WRITE_iTXt_SUPPORTED |
/* Write an iTXt chunk */ |
void /* PRIVATE */ |
png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key, |
png_const_charp lang, png_const_charp lang_key, png_const_charp text) |
{ |
png_uint_32 key_len, prefix_len; |
png_size_t lang_len, lang_key_len; |
png_byte new_key[82]; |
compression_state comp; |
|
png_debug(1, "in png_write_iTXt"); |
|
key_len = png_check_keyword(png_ptr, key, new_key); |
|
if (key_len == 0) |
png_error(png_ptr, "iTXt: invalid keyword"); |
|
/* Set the compression flag */ |
switch (compression) |
{ |
case PNG_ITXT_COMPRESSION_NONE: |
case PNG_TEXT_COMPRESSION_NONE: |
compression = new_key[++key_len] = 0; /* no compression */ |
break; |
|
case PNG_TEXT_COMPRESSION_zTXt: |
case PNG_ITXT_COMPRESSION_zTXt: |
compression = new_key[++key_len] = 1; /* compressed */ |
break; |
|
default: |
png_error(png_ptr, "iTXt: invalid compression"); |
} |
|
new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE; |
++key_len; /* for the keywod separator */ |
|
/* We leave it to the application to meet PNG-1.0 requirements on the |
* contents of the text. PNG-1.0 through PNG-1.2 discourage the use of |
* any non-Latin-1 characters except for NEWLINE. ISO PNG, however, |
* specifies that the text is UTF-8 and this really doesn't require any |
* checking. |
* |
* The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. |
* |
* TODO: validate the language tag correctly (see the spec.) |
*/ |
if (lang == NULL) lang = ""; /* empty language is valid */ |
lang_len = strlen(lang)+1; |
if (lang_key == NULL) lang_key = ""; /* may be empty */ |
lang_key_len = strlen(lang_key)+1; |
if (text == NULL) text = ""; /* may be empty */ |
|
prefix_len = key_len; |
if (lang_len > PNG_UINT_31_MAX-prefix_len) |
prefix_len = PNG_UINT_31_MAX; |
else |
prefix_len = (png_uint_32)(prefix_len + lang_len); |
|
if (lang_key_len > PNG_UINT_31_MAX-prefix_len) |
prefix_len = PNG_UINT_31_MAX; |
else |
prefix_len = (png_uint_32)(prefix_len + lang_key_len); |
|
png_text_compress_init(&comp, (png_const_bytep)text, strlen(text)); |
|
if (compression) |
{ |
if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK) |
png_error(png_ptr, png_ptr->zstream.msg); |
} |
|
else |
{ |
if (comp.input_len > PNG_UINT_31_MAX-prefix_len) |
png_error(png_ptr, "iTXt: uncompressed text too long"); |
|
/* So the string will fit in a chunk: */ |
comp.output_len = (png_uint_32)/*SAFE*/comp.input_len; |
} |
|
png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len); |
|
png_write_chunk_data(png_ptr, new_key, key_len); |
|
png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len); |
|
png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len); |
|
if (compression) |
png_write_compressed_data_out(png_ptr, &comp); |
|
else |
png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.input_len); |
|
png_write_chunk_end(png_ptr); |
} |
#endif |
|
#ifdef PNG_WRITE_oFFs_SUPPORTED |
/* Write the oFFs chunk */ |
void /* PRIVATE */ |
png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset, |
int unit_type) |
{ |
png_byte buf[9]; |
|
png_debug(1, "in png_write_oFFs"); |
|
if (unit_type >= PNG_OFFSET_LAST) |
png_warning(png_ptr, "Unrecognized unit type for oFFs chunk"); |
|
png_save_int_32(buf, x_offset); |
png_save_int_32(buf + 4, y_offset); |
buf[8] = (png_byte)unit_type; |
|
png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9); |
} |
#endif |
#ifdef PNG_WRITE_pCAL_SUPPORTED |
/* Write the pCAL chunk (described in the PNG extensions document) */ |
void /* PRIVATE */ |
png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0, |
png_int_32 X1, int type, int nparams, png_const_charp units, |
png_charpp params) |
{ |
png_uint_32 purpose_len; |
png_size_t units_len, total_len; |
png_size_tp params_len; |
png_byte buf[10]; |
png_byte new_purpose[80]; |
int i; |
|
png_debug1(1, "in png_write_pCAL (%d parameters)", nparams); |
|
if (type >= PNG_EQUATION_LAST) |
png_error(png_ptr, "Unrecognized equation type for pCAL chunk"); |
|
purpose_len = png_check_keyword(png_ptr, purpose, new_purpose); |
|
if (purpose_len == 0) |
png_error(png_ptr, "pCAL: invalid keyword"); |
|
++purpose_len; /* terminator */ |
|
png_debug1(3, "pCAL purpose length = %d", (int)purpose_len); |
units_len = strlen(units) + (nparams == 0 ? 0 : 1); |
png_debug1(3, "pCAL units length = %d", (int)units_len); |
total_len = purpose_len + units_len + 10; |
|
params_len = (png_size_tp)png_malloc(png_ptr, |
(png_alloc_size_t)(nparams * (sizeof (png_size_t)))); |
|
/* Find the length of each parameter, making sure we don't count the |
* null terminator for the last parameter. |
*/ |
for (i = 0; i < nparams; i++) |
{ |
params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1); |
png_debug2(3, "pCAL parameter %d length = %lu", i, |
(unsigned long)params_len[i]); |
total_len += params_len[i]; |
} |
|
png_debug1(3, "pCAL total length = %d", (int)total_len); |
png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len); |
png_write_chunk_data(png_ptr, new_purpose, purpose_len); |
png_save_int_32(buf, X0); |
png_save_int_32(buf + 4, X1); |
buf[8] = (png_byte)type; |
buf[9] = (png_byte)nparams; |
png_write_chunk_data(png_ptr, buf, (png_size_t)10); |
png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len); |
|
for (i = 0; i < nparams; i++) |
{ |
png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]); |
} |
|
png_free(png_ptr, params_len); |
png_write_chunk_end(png_ptr); |
} |
#endif |
|
#ifdef PNG_WRITE_sCAL_SUPPORTED |
/* Write the sCAL chunk */ |
void /* PRIVATE */ |
png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width, |
png_const_charp height) |
{ |
png_byte buf[64]; |
png_size_t wlen, hlen, total_len; |
|
png_debug(1, "in png_write_sCAL_s"); |
|
wlen = strlen(width); |
hlen = strlen(height); |
total_len = wlen + hlen + 2; |
|
if (total_len > 64) |
{ |
png_warning(png_ptr, "Can't write sCAL (buffer too small)"); |
return; |
} |
|
buf[0] = (png_byte)unit; |
memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */ |
memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */ |
|
png_debug1(3, "sCAL total length = %u", (unsigned int)total_len); |
png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len); |
} |
#endif |
|
#ifdef PNG_WRITE_pHYs_SUPPORTED |
/* Write the pHYs chunk */ |
void /* PRIVATE */ |
png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit, |
png_uint_32 y_pixels_per_unit, |
int unit_type) |
{ |
png_byte buf[9]; |
|
png_debug(1, "in png_write_pHYs"); |
|
if (unit_type >= PNG_RESOLUTION_LAST) |
png_warning(png_ptr, "Unrecognized unit type for pHYs chunk"); |
|
png_save_uint_32(buf, x_pixels_per_unit); |
png_save_uint_32(buf + 4, y_pixels_per_unit); |
buf[8] = (png_byte)unit_type; |
|
png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9); |
} |
#endif |
|
#ifdef PNG_WRITE_tIME_SUPPORTED |
/* Write the tIME chunk. Use either png_convert_from_struct_tm() |
* or png_convert_from_time_t(), or fill in the structure yourself. |
*/ |
void /* PRIVATE */ |
png_write_tIME(png_structrp png_ptr, png_const_timep mod_time) |
{ |
png_byte buf[7]; |
|
png_debug(1, "in png_write_tIME"); |
|
if (mod_time->month > 12 || mod_time->month < 1 || |
mod_time->day > 31 || mod_time->day < 1 || |
mod_time->hour > 23 || mod_time->second > 60) |
{ |
png_warning(png_ptr, "Invalid time specified for tIME chunk"); |
return; |
} |
|
png_save_uint_16(buf, mod_time->year); |
buf[2] = mod_time->month; |
buf[3] = mod_time->day; |
buf[4] = mod_time->hour; |
buf[5] = mod_time->minute; |
buf[6] = mod_time->second; |
|
png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7); |
} |
#endif |
|
/* Initializes the row writing capability of libpng */ |
void /* PRIVATE */ |
png_write_start_row(png_structrp png_ptr) |
{ |
#ifdef PNG_WRITE_INTERLACING_SUPPORTED |
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ |
|
/* Start of interlace block */ |
static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; |
|
/* Offset to next interlace block */ |
static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; |
|
/* Start of interlace block in the y direction */ |
static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; |
|
/* Offset to next interlace block in the y direction */ |
static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; |
#endif |
|
png_alloc_size_t buf_size; |
int usr_pixel_depth; |
|
png_debug(1, "in png_write_start_row"); |
|
usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth; |
buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1; |
|
/* 1.5.6: added to allow checking in the row write code. */ |
png_ptr->transformed_pixel_depth = png_ptr->pixel_depth; |
png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth; |
|
/* Set up row buffer */ |
png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size); |
|
png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE; |
|
#ifdef PNG_WRITE_FILTER_SUPPORTED |
/* Set up filtering buffer, if using this filter */ |
if (png_ptr->do_filter & PNG_FILTER_SUB) |
{ |
png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1); |
|
png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB; |
} |
|
/* We only need to keep the previous row if we are using one of these. */ |
if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) |
{ |
/* Set up previous row buffer */ |
png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size); |
|
if (png_ptr->do_filter & PNG_FILTER_UP) |
{ |
png_ptr->up_row = (png_bytep)png_malloc(png_ptr, |
png_ptr->rowbytes + 1); |
|
png_ptr->up_row[0] = PNG_FILTER_VALUE_UP; |
} |
|
if (png_ptr->do_filter & PNG_FILTER_AVG) |
{ |
png_ptr->avg_row = (png_bytep)png_malloc(png_ptr, |
png_ptr->rowbytes + 1); |
|
png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG; |
} |
|
if (png_ptr->do_filter & PNG_FILTER_PAETH) |
{ |
png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr, |
png_ptr->rowbytes + 1); |
|
png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH; |
} |
} |
#endif /* PNG_WRITE_FILTER_SUPPORTED */ |
|
#ifdef PNG_WRITE_INTERLACING_SUPPORTED |
/* If interlaced, we need to set up width and height of pass */ |
if (png_ptr->interlaced) |
{ |
if (!(png_ptr->transformations & PNG_INTERLACE)) |
{ |
png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - |
png_pass_ystart[0]) / png_pass_yinc[0]; |
|
png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 - |
png_pass_start[0]) / png_pass_inc[0]; |
} |
|
else |
{ |
png_ptr->num_rows = png_ptr->height; |
png_ptr->usr_width = png_ptr->width; |
} |
} |
|
else |
#endif |
{ |
png_ptr->num_rows = png_ptr->height; |
png_ptr->usr_width = png_ptr->width; |
} |
} |
|
/* Internal use only. Called when finished processing a row of data. */ |
void /* PRIVATE */ |
png_write_finish_row(png_structrp png_ptr) |
{ |
#ifdef PNG_WRITE_INTERLACING_SUPPORTED |
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ |
|
/* Start of interlace block */ |
static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; |
|
/* Offset to next interlace block */ |
static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; |
|
/* Start of interlace block in the y direction */ |
static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; |
|
/* Offset to next interlace block in the y direction */ |
static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; |
#endif |
|
png_debug(1, "in png_write_finish_row"); |
|
/* Next row */ |
png_ptr->row_number++; |
|
/* See if we are done */ |
if (png_ptr->row_number < png_ptr->num_rows) |
return; |
|
#ifdef PNG_WRITE_INTERLACING_SUPPORTED |
/* If interlaced, go to next pass */ |
if (png_ptr->interlaced) |
{ |
png_ptr->row_number = 0; |
if (png_ptr->transformations & PNG_INTERLACE) |
{ |
png_ptr->pass++; |
} |
|
else |
{ |
/* Loop until we find a non-zero width or height pass */ |
do |
{ |
png_ptr->pass++; |
|
if (png_ptr->pass >= 7) |
break; |
|
png_ptr->usr_width = (png_ptr->width + |
png_pass_inc[png_ptr->pass] - 1 - |
png_pass_start[png_ptr->pass]) / |
png_pass_inc[png_ptr->pass]; |
|
png_ptr->num_rows = (png_ptr->height + |
png_pass_yinc[png_ptr->pass] - 1 - |
png_pass_ystart[png_ptr->pass]) / |
png_pass_yinc[png_ptr->pass]; |
|
if (png_ptr->transformations & PNG_INTERLACE) |
break; |
|
} while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0); |
|
} |
|
/* Reset the row above the image for the next pass */ |
if (png_ptr->pass < 7) |
{ |
if (png_ptr->prev_row != NULL) |
memset(png_ptr->prev_row, 0, |
(png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels* |
png_ptr->usr_bit_depth, png_ptr->width)) + 1); |
|
return; |
} |
} |
#endif |
|
/* If we get here, we've just written the last row, so we need |
to flush the compressor */ |
png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH); |
} |
|
#ifdef PNG_WRITE_INTERLACING_SUPPORTED |
/* Pick out the correct pixels for the interlace pass. |
* The basic idea here is to go through the row with a source |
* pointer and a destination pointer (sp and dp), and copy the |
* correct pixels for the pass. As the row gets compacted, |
* sp will always be >= dp, so we should never overwrite anything. |
* See the default: case for the easiest code to understand. |
*/ |
void /* PRIVATE */ |
png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass) |
{ |
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ |
|
/* Start of interlace block */ |
static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; |
|
/* Offset to next interlace block */ |
static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; |
|
png_debug(1, "in png_do_write_interlace"); |
|
/* We don't have to do anything on the last pass (6) */ |
if (pass < 6) |
{ |
/* Each pixel depth is handled separately */ |
switch (row_info->pixel_depth) |
{ |
case 1: |
{ |
png_bytep sp; |
png_bytep dp; |
int shift; |
int d; |
int value; |
png_uint_32 i; |
png_uint_32 row_width = row_info->width; |
|
dp = row; |
d = 0; |
shift = 7; |
|
for (i = png_pass_start[pass]; i < row_width; |
i += png_pass_inc[pass]) |
{ |
sp = row + (png_size_t)(i >> 3); |
value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01; |
d |= (value << shift); |
|
if (shift == 0) |
{ |
shift = 7; |
*dp++ = (png_byte)d; |
d = 0; |
} |
|
else |
shift--; |
|
} |
if (shift != 7) |
*dp = (png_byte)d; |
|
break; |
} |
|
case 2: |
{ |
png_bytep sp; |
png_bytep dp; |
int shift; |
int d; |
int value; |
png_uint_32 i; |
png_uint_32 row_width = row_info->width; |
|
dp = row; |
shift = 6; |
d = 0; |
|
for (i = png_pass_start[pass]; i < row_width; |
i += png_pass_inc[pass]) |
{ |
sp = row + (png_size_t)(i >> 2); |
value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03; |
d |= (value << shift); |
|
if (shift == 0) |
{ |
shift = 6; |
*dp++ = (png_byte)d; |
d = 0; |
} |
|
else |
shift -= 2; |
} |
if (shift != 6) |
*dp = (png_byte)d; |
|
break; |
} |
|
case 4: |
{ |
png_bytep sp; |
png_bytep dp; |
int shift; |
int d; |
int value; |
png_uint_32 i; |
png_uint_32 row_width = row_info->width; |
|
dp = row; |
shift = 4; |
d = 0; |
for (i = png_pass_start[pass]; i < row_width; |
i += png_pass_inc[pass]) |
{ |
sp = row + (png_size_t)(i >> 1); |
value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f; |
d |= (value << shift); |
|
if (shift == 0) |
{ |
shift = 4; |
*dp++ = (png_byte)d; |
d = 0; |
} |
|
else |
shift -= 4; |
} |
if (shift != 4) |
*dp = (png_byte)d; |
|
break; |
} |
|
default: |
{ |
png_bytep sp; |
png_bytep dp; |
png_uint_32 i; |
png_uint_32 row_width = row_info->width; |
png_size_t pixel_bytes; |
|
/* Start at the beginning */ |
dp = row; |
|
/* Find out how many bytes each pixel takes up */ |
pixel_bytes = (row_info->pixel_depth >> 3); |
|
/* Loop through the row, only looking at the pixels that matter */ |
for (i = png_pass_start[pass]; i < row_width; |
i += png_pass_inc[pass]) |
{ |
/* Find out where the original pixel is */ |
sp = row + (png_size_t)i * pixel_bytes; |
|
/* Move the pixel */ |
if (dp != sp) |
memcpy(dp, sp, pixel_bytes); |
|
/* Next pixel */ |
dp += pixel_bytes; |
} |
break; |
} |
} |
/* Set new row width */ |
row_info->width = (row_info->width + |
png_pass_inc[pass] - 1 - |
png_pass_start[pass]) / |
png_pass_inc[pass]; |
|
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, |
row_info->width); |
} |
} |
#endif |
|
/* This filters the row, chooses which filter to use, if it has not already |
* been specified by the application, and then writes the row out with the |
* chosen filter. |
*/ |
static void png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row, |
png_size_t row_bytes); |
|
#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1) |
#define PNG_HISHIFT 10 |
#define PNG_LOMASK ((png_uint_32)0xffffL) |
#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT)) |
void /* PRIVATE */ |
png_write_find_filter(png_structrp png_ptr, png_row_infop row_info) |
{ |
png_bytep best_row; |
#ifdef PNG_WRITE_FILTER_SUPPORTED |
png_bytep prev_row, row_buf; |
png_uint_32 mins, bpp; |
png_byte filter_to_do = png_ptr->do_filter; |
png_size_t row_bytes = row_info->rowbytes; |
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
int num_p_filters = png_ptr->num_prev_filters; |
#endif |
|
png_debug(1, "in png_write_find_filter"); |
|
#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS) |
{ |
/* These will never be selected so we need not test them. */ |
filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH); |
} |
#endif |
|
/* Find out how many bytes offset each pixel is */ |
bpp = (row_info->pixel_depth + 7) >> 3; |
|
prev_row = png_ptr->prev_row; |
#endif |
best_row = png_ptr->row_buf; |
#ifdef PNG_WRITE_FILTER_SUPPORTED |
row_buf = best_row; |
mins = PNG_MAXSUM; |
|
/* The prediction method we use is to find which method provides the |
* smallest value when summing the absolute values of the distances |
* from zero, using anything >= 128 as negative numbers. This is known |
* as the "minimum sum of absolute differences" heuristic. Other |
* heuristics are the "weighted minimum sum of absolute differences" |
* (experimental and can in theory improve compression), and the "zlib |
* predictive" method (not implemented yet), which does test compressions |
* of lines using different filter methods, and then chooses the |
* (series of) filter(s) that give minimum compressed data size (VERY |
* computationally expensive). |
* |
* GRR 980525: consider also |
* |
* (1) minimum sum of absolute differences from running average (i.e., |
* keep running sum of non-absolute differences & count of bytes) |
* [track dispersion, too? restart average if dispersion too large?] |
* |
* (1b) minimum sum of absolute differences from sliding average, probably |
* with window size <= deflate window (usually 32K) |
* |
* (2) minimum sum of squared differences from zero or running average |
* (i.e., ~ root-mean-square approach) |
*/ |
|
|
/* We don't need to test the 'no filter' case if this is the only filter |
* that has been chosen, as it doesn't actually do anything to the data. |
*/ |
if ((filter_to_do & PNG_FILTER_NONE) && filter_to_do != PNG_FILTER_NONE) |
{ |
png_bytep rp; |
png_uint_32 sum = 0; |
png_size_t i; |
int v; |
|
for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++) |
{ |
v = *rp; |
sum += (v < 128) ? v : 256 - v; |
} |
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
png_uint_32 sumhi, sumlo; |
int j; |
sumlo = sum & PNG_LOMASK; |
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */ |
|
/* Reduce the sum if we match any of the previous rows */ |
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE) |
{ |
sumlo = (sumlo * png_ptr->filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
sumhi = (sumhi * png_ptr->filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
/* Factor in the cost of this filter (this is here for completeness, |
* but it makes no sense to have a "cost" for the NONE filter, as |
* it has the minimum possible computational cost - none). |
*/ |
sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >> |
PNG_COST_SHIFT; |
|
sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >> |
PNG_COST_SHIFT; |
|
if (sumhi > PNG_HIMASK) |
sum = PNG_MAXSUM; |
|
else |
sum = (sumhi << PNG_HISHIFT) + sumlo; |
} |
#endif |
mins = sum; |
} |
|
/* Sub filter */ |
if (filter_to_do == PNG_FILTER_SUB) |
/* It's the only filter so no testing is needed */ |
{ |
png_bytep rp, lp, dp; |
png_size_t i; |
|
for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; |
i++, rp++, dp++) |
{ |
*dp = *rp; |
} |
|
for (lp = row_buf + 1; i < row_bytes; |
i++, rp++, lp++, dp++) |
{ |
*dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); |
} |
|
best_row = png_ptr->sub_row; |
} |
|
else if (filter_to_do & PNG_FILTER_SUB) |
{ |
png_bytep rp, dp, lp; |
png_uint_32 sum = 0, lmins = mins; |
png_size_t i; |
int v; |
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
/* We temporarily increase the "minimum sum" by the factor we |
* would reduce the sum of this filter, so that we can do the |
* early exit comparison without scaling the sum each time. |
*/ |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
int j; |
png_uint_32 lmhi, lmlo; |
lmlo = lmins & PNG_LOMASK; |
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; |
|
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB) |
{ |
lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> |
PNG_COST_SHIFT; |
|
lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> |
PNG_COST_SHIFT; |
|
if (lmhi > PNG_HIMASK) |
lmins = PNG_MAXSUM; |
|
else |
lmins = (lmhi << PNG_HISHIFT) + lmlo; |
} |
#endif |
|
for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp; |
i++, rp++, dp++) |
{ |
v = *dp = *rp; |
|
sum += (v < 128) ? v : 256 - v; |
} |
|
for (lp = row_buf + 1; i < row_bytes; |
i++, rp++, lp++, dp++) |
{ |
v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); |
|
sum += (v < 128) ? v : 256 - v; |
|
if (sum > lmins) /* We are already worse, don't continue. */ |
break; |
} |
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
int j; |
png_uint_32 sumhi, sumlo; |
sumlo = sum & PNG_LOMASK; |
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; |
|
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB) |
{ |
sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> |
PNG_COST_SHIFT; |
|
sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >> |
PNG_COST_SHIFT; |
|
if (sumhi > PNG_HIMASK) |
sum = PNG_MAXSUM; |
|
else |
sum = (sumhi << PNG_HISHIFT) + sumlo; |
} |
#endif |
|
if (sum < mins) |
{ |
mins = sum; |
best_row = png_ptr->sub_row; |
} |
} |
|
/* Up filter */ |
if (filter_to_do == PNG_FILTER_UP) |
{ |
png_bytep rp, dp, pp; |
png_size_t i; |
|
for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, |
pp = prev_row + 1; i < row_bytes; |
i++, rp++, pp++, dp++) |
{ |
*dp = (png_byte)(((int)*rp - (int)*pp) & 0xff); |
} |
|
best_row = png_ptr->up_row; |
} |
|
else if (filter_to_do & PNG_FILTER_UP) |
{ |
png_bytep rp, dp, pp; |
png_uint_32 sum = 0, lmins = mins; |
png_size_t i; |
int v; |
|
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
int j; |
png_uint_32 lmhi, lmlo; |
lmlo = lmins & PNG_LOMASK; |
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; |
|
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP) |
{ |
lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >> |
PNG_COST_SHIFT; |
|
lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >> |
PNG_COST_SHIFT; |
|
if (lmhi > PNG_HIMASK) |
lmins = PNG_MAXSUM; |
|
else |
lmins = (lmhi << PNG_HISHIFT) + lmlo; |
} |
#endif |
|
for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1, |
pp = prev_row + 1; i < row_bytes; i++) |
{ |
v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); |
|
sum += (v < 128) ? v : 256 - v; |
|
if (sum > lmins) /* We are already worse, don't continue. */ |
break; |
} |
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
int j; |
png_uint_32 sumhi, sumlo; |
sumlo = sum & PNG_LOMASK; |
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; |
|
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP) |
{ |
sumlo = (sumlo * png_ptr->filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
sumhi = (sumhi * png_ptr->filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >> |
PNG_COST_SHIFT; |
|
sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >> |
PNG_COST_SHIFT; |
|
if (sumhi > PNG_HIMASK) |
sum = PNG_MAXSUM; |
|
else |
sum = (sumhi << PNG_HISHIFT) + sumlo; |
} |
#endif |
|
if (sum < mins) |
{ |
mins = sum; |
best_row = png_ptr->up_row; |
} |
} |
|
/* Avg filter */ |
if (filter_to_do == PNG_FILTER_AVG) |
{ |
png_bytep rp, dp, pp, lp; |
png_uint_32 i; |
|
for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, |
pp = prev_row + 1; i < bpp; i++) |
{ |
*dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); |
} |
|
for (lp = row_buf + 1; i < row_bytes; i++) |
{ |
*dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) |
& 0xff); |
} |
best_row = png_ptr->avg_row; |
} |
|
else if (filter_to_do & PNG_FILTER_AVG) |
{ |
png_bytep rp, dp, pp, lp; |
png_uint_32 sum = 0, lmins = mins; |
png_size_t i; |
int v; |
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
int j; |
png_uint_32 lmhi, lmlo; |
lmlo = lmins & PNG_LOMASK; |
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; |
|
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG) |
{ |
lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >> |
PNG_COST_SHIFT; |
|
lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >> |
PNG_COST_SHIFT; |
|
if (lmhi > PNG_HIMASK) |
lmins = PNG_MAXSUM; |
|
else |
lmins = (lmhi << PNG_HISHIFT) + lmlo; |
} |
#endif |
|
for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1, |
pp = prev_row + 1; i < bpp; i++) |
{ |
v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); |
|
sum += (v < 128) ? v : 256 - v; |
} |
|
for (lp = row_buf + 1; i < row_bytes; i++) |
{ |
v = *dp++ = |
(png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff); |
|
sum += (v < 128) ? v : 256 - v; |
|
if (sum > lmins) /* We are already worse, don't continue. */ |
break; |
} |
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
int j; |
png_uint_32 sumhi, sumlo; |
sumlo = sum & PNG_LOMASK; |
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; |
|
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE) |
{ |
sumlo = (sumlo * png_ptr->filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
sumhi = (sumhi * png_ptr->filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >> |
PNG_COST_SHIFT; |
|
sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >> |
PNG_COST_SHIFT; |
|
if (sumhi > PNG_HIMASK) |
sum = PNG_MAXSUM; |
|
else |
sum = (sumhi << PNG_HISHIFT) + sumlo; |
} |
#endif |
|
if (sum < mins) |
{ |
mins = sum; |
best_row = png_ptr->avg_row; |
} |
} |
|
/* Paeth filter */ |
if (filter_to_do == PNG_FILTER_PAETH) |
{ |
png_bytep rp, dp, pp, cp, lp; |
png_size_t i; |
|
for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, |
pp = prev_row + 1; i < bpp; i++) |
{ |
*dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); |
} |
|
for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) |
{ |
int a, b, c, pa, pb, pc, p; |
|
b = *pp++; |
c = *cp++; |
a = *lp++; |
|
p = b - c; |
pc = a - c; |
|
#ifdef PNG_USE_ABS |
pa = abs(p); |
pb = abs(pc); |
pc = abs(p + pc); |
#else |
pa = p < 0 ? -p : p; |
pb = pc < 0 ? -pc : pc; |
pc = (p + pc) < 0 ? -(p + pc) : p + pc; |
#endif |
|
p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; |
|
*dp++ = (png_byte)(((int)*rp++ - p) & 0xff); |
} |
best_row = png_ptr->paeth_row; |
} |
|
else if (filter_to_do & PNG_FILTER_PAETH) |
{ |
png_bytep rp, dp, pp, cp, lp; |
png_uint_32 sum = 0, lmins = mins; |
png_size_t i; |
int v; |
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
int j; |
png_uint_32 lmhi, lmlo; |
lmlo = lmins & PNG_LOMASK; |
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK; |
|
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH) |
{ |
lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >> |
PNG_COST_SHIFT; |
|
lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >> |
PNG_COST_SHIFT; |
|
if (lmhi > PNG_HIMASK) |
lmins = PNG_MAXSUM; |
|
else |
lmins = (lmhi << PNG_HISHIFT) + lmlo; |
} |
#endif |
|
for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1, |
pp = prev_row + 1; i < bpp; i++) |
{ |
v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); |
|
sum += (v < 128) ? v : 256 - v; |
} |
|
for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++) |
{ |
int a, b, c, pa, pb, pc, p; |
|
b = *pp++; |
c = *cp++; |
a = *lp++; |
|
#ifndef PNG_SLOW_PAETH |
p = b - c; |
pc = a - c; |
#ifdef PNG_USE_ABS |
pa = abs(p); |
pb = abs(pc); |
pc = abs(p + pc); |
#else |
pa = p < 0 ? -p : p; |
pb = pc < 0 ? -pc : pc; |
pc = (p + pc) < 0 ? -(p + pc) : p + pc; |
#endif |
p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; |
#else /* PNG_SLOW_PAETH */ |
p = a + b - c; |
pa = abs(p - a); |
pb = abs(p - b); |
pc = abs(p - c); |
|
if (pa <= pb && pa <= pc) |
p = a; |
|
else if (pb <= pc) |
p = b; |
|
else |
p = c; |
#endif /* PNG_SLOW_PAETH */ |
|
v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); |
|
sum += (v < 128) ? v : 256 - v; |
|
if (sum > lmins) /* We are already worse, don't continue. */ |
break; |
} |
|
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED) |
{ |
int j; |
png_uint_32 sumhi, sumlo; |
sumlo = sum & PNG_LOMASK; |
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; |
|
for (j = 0; j < num_p_filters; j++) |
{ |
if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH) |
{ |
sumlo = (sumlo * png_ptr->filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
|
sumhi = (sumhi * png_ptr->filter_weights[j]) >> |
PNG_WEIGHT_SHIFT; |
} |
} |
|
sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >> |
PNG_COST_SHIFT; |
|
sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >> |
PNG_COST_SHIFT; |
|
if (sumhi > PNG_HIMASK) |
sum = PNG_MAXSUM; |
|
else |
sum = (sumhi << PNG_HISHIFT) + sumlo; |
} |
#endif |
|
if (sum < mins) |
{ |
best_row = png_ptr->paeth_row; |
} |
} |
#endif /* PNG_WRITE_FILTER_SUPPORTED */ |
|
/* Do the actual writing of the filtered row data from the chosen filter. */ |
png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1); |
|
#ifdef PNG_WRITE_FILTER_SUPPORTED |
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED |
/* Save the type of filter we picked this time for future calculations */ |
if (png_ptr->num_prev_filters > 0) |
{ |
int j; |
|
for (j = 1; j < num_p_filters; j++) |
{ |
png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1]; |
} |
|
png_ptr->prev_filters[j] = best_row[0]; |
} |
#endif |
#endif /* PNG_WRITE_FILTER_SUPPORTED */ |
} |
|
|
/* Do the actual writing of a previously filtered row. */ |
static void |
png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row, |
png_size_t full_row_length/*includes filter byte*/) |
{ |
png_debug(1, "in png_write_filtered_row"); |
|
png_debug1(2, "filter = %d", filtered_row[0]); |
|
png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH); |
|
/* Swap the current and previous rows */ |
if (png_ptr->prev_row != NULL) |
{ |
png_bytep tptr; |
|
tptr = png_ptr->prev_row; |
png_ptr->prev_row = png_ptr->row_buf; |
png_ptr->row_buf = tptr; |
} |
|
/* Finish row - updates counters and flushes zlib if last row */ |
png_write_finish_row(png_ptr); |
|
#ifdef PNG_WRITE_FLUSH_SUPPORTED |
png_ptr->flush_rows++; |
|
if (png_ptr->flush_dist > 0 && |
png_ptr->flush_rows >= png_ptr->flush_dist) |
{ |
png_write_flush(png_ptr); |
} |
#endif |
} |
#endif /* PNG_WRITE_SUPPORTED */ |