/* pngwutil.c - utilities to write a PNG file
*
- * Last changed in libpng 1.6.11 [June 5, 2014]
- * Copyright (c) 1998-2014 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.)
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
+ * Copyright (c) 1996-1997 Andreas Dilger
+ * 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
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);
+ buf[0] = (png_byte)((i >> 24) & 0xffU);
+ buf[1] = (png_byte)((i >> 16) & 0xffU);
+ buf[2] = (png_byte)((i >> 8) & 0xffU);
+ buf[3] = (png_byte)( i & 0xffU);
}
/* Place a 16-bit number into a buffer in PNG byte order.
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);
+ buf[0] = (png_byte)((i >> 8) & 0xffU);
+ buf[1] = (png_byte)( i & 0xffU);
}
#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));
+ (size_t)(8 - png_ptr->sig_bytes));
if (png_ptr->sig_bytes < 3)
png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
* given to png_write_chunk_header().
*/
void PNGAPI
-png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
- png_size_t length)
+png_write_chunk_data(png_structrp png_ptr, png_const_bytep data, size_t length)
{
/* Write the data, and run the CRC over it */
if (png_ptr == NULL)
png_write_data(png_ptr, data, length);
/* Update the CRC after writing the data,
- * in case that the user I/O routine alters it.
+ * in case the user I/O routine alters it.
*/
png_calculate_crc(png_ptr, data, length);
}
/* 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);
+ png_write_data(png_ptr, buf, 4);
}
/* Write a PNG chunk all at once. The type is an array of ASCII characters
*/
static void
png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
- png_const_bytep data, png_size_t length)
+ png_const_bytep data, size_t length)
{
if (png_ptr == NULL)
return;
- /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
+ /* 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_error(png_ptr, "length exceeds PNG maximum");
png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
png_write_chunk_data(png_ptr, data, length);
/* 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_const_bytep data, size_t length)
{
png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
- length);
+ length);
}
/* This is used below to find the size of an image to pass to png_deflate_claim,
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
+ /* 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)
+ 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.
}
}
}
-#else
-# define optimize_cmf(dp,dl) ((void)0)
-#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
+#endif /* WRITE_OPTIMIZE_CMF */
/* 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)
+ png_alloc_size_t data_size)
{
if (png_ptr->zowner != 0)
{
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
char msg[64];
PNG_STRING_FROM_CHUNK(msg, owner);
* are minimal.
*/
(void)png_safecat(msg, (sizeof msg), 10, " using zstream");
-# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+#endif
+#if PNG_RELEASE_BUILD
png_warning(png_ptr, msg);
/* Attempt sane error recovery */
}
png_ptr->zowner = 0;
-# else
+#else
png_error(png_ptr, msg);
-# endif
+#endif
}
{
if (owner == png_IDAT)
{
- if (png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY)
+ if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
strategy = png_ptr->zlib_strategy;
else if (png_ptr->do_filter != PNG_FILTER_NONE)
else
{
-# ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#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
+#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
+#endif
}
/* Adjust 'windowBits' down if larger than 'data_size'; to stop this
}
/* Check against the previous initialized values, if any. */
- if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) &&
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
(png_ptr->zlib_set_level != level ||
png_ptr->zlib_set_method != method ||
png_ptr->zlib_set_window_bits != windowBits ||
png_ptr->zstream.avail_out = 0;
/* Now initialize if required, setting the new parameters, otherwise just
- * to a simple reset to the previous parameters.
+ * do a simple reset to the previous parameters.
*/
- if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED)
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
ret = deflateReset(&png_ptr->zstream);
else
{
ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
- memLevel, strategy);
+ memLevel, strategy);
if (ret == Z_OK)
png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
static void
png_text_compress_init(compression_state *comp, png_const_bytep input,
- png_alloc_size_t input_len)
+ png_alloc_size_t input_len)
{
comp->input = input;
comp->input_len = input_len;
/* 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)
+ 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
+ * 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.
*
/* Compress the data */
ret = deflate(&png_ptr->zstream,
- input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
+ 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).
}
while (ret == Z_OK);
- /* There may be some space left in the last output buffer, this needs to
+ /* 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;
/* 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
+ /* 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)
{
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
/* Fix up the deflate header, if required */
optimize_cmf(comp->output, comp->input_len);
-
+#endif
/* 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.)
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 == 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) /* 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;
-
- /* Try to only output one warning per keyword: */
- if (*key) /* keyword too long */
- png_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'");
- }
-
- return key_len;
-}
-#endif
+#endif /* WRITE_COMPRESSED_TEXT */
/* Write the IHDR chunk, and update the png_struct with the necessary
* information. Note that the rest of this code depends upon this
int interlace_type)
{
png_byte buf[13]; /* Buffer to store the IHDR info */
+ int is_invalid_depth;
png_debug(1, "in png_write_IHDR");
break;
case PNG_COLOR_TYPE_RGB:
+ is_invalid_depth = (bit_depth != 8);
#ifdef PNG_WRITE_16BIT_SUPPORTED
- if (bit_depth != 8 && bit_depth != 16)
-#else
- if (bit_depth != 8)
+ is_invalid_depth = (is_invalid_depth && bit_depth != 16);
#endif
+ if (is_invalid_depth)
png_error(png_ptr, "Invalid bit depth for RGB image");
png_ptr->channels = 3;
break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
- if (bit_depth != 8 && bit_depth != 16)
+ is_invalid_depth = (bit_depth != 8);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ is_invalid_depth = (is_invalid_depth && bit_depth != 16);
+#endif
+ if (is_invalid_depth)
png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
png_ptr->channels = 2;
break;
case PNG_COLOR_TYPE_RGB_ALPHA:
+ is_invalid_depth = (bit_depth != 8);
#ifdef PNG_WRITE_16BIT_SUPPORTED
- if (bit_depth != 8 && bit_depth != 16)
-#else
- if (bit_depth != 8)
+ is_invalid_depth = (is_invalid_depth && bit_depth != 16);
#endif
+ if (is_invalid_depth)
png_error(png_ptr, "Invalid bit depth for RGBA image");
png_ptr->channels = 4;
*/
if (
#ifdef PNG_MNG_FEATURES_SUPPORTED
- !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
- ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+ !((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_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
interlace_type=PNG_INTERLACE_NONE;
#endif
- /* Save the relevent information */
+ /* Save the relevant information */
png_ptr->bit_depth = (png_byte)bit_depth;
png_ptr->color_type = (png_byte)color_type;
png_ptr->interlaced = (png_byte)interlace_type;
buf[12] = (png_byte)interlace_type;
/* Write the chunk */
- png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
+ png_write_complete_chunk(png_ptr, png_IHDR, buf, 13);
+
+#ifdef PNG_WRITE_APNG_SUPPORTED
+ png_ptr->first_frame_width = width;
+ png_ptr->first_frame_height = height;
+#endif
if ((png_ptr->do_filter) == PNG_NO_FILTERS)
{
png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
png_uint_32 num_pal)
{
- png_uint_32 i;
+ 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) &&
+ (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
#endif
- num_pal == 0) || num_pal > 256)
+ num_pal == 0) || num_pal > max_palette_length)
{
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
}
}
- if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+ if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
{
png_warning(png_ptr,
"Ignoring request to write a PLTE chunk in grayscale PNG");
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);
+ png_write_chunk_data(png_ptr, buf, 3);
}
#else
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);
+ png_write_chunk_data(png_ptr, buf, 3);
}
#endif
* 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
+ * 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)
+ png_alloc_size_t input_len, int flush)
{
if (png_ptr->zowner != png_IDAT)
{
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_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
png_ptr->zbuffer_list->next = NULL;
}
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
+ /* 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.
*/
/* 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)
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+ png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
optimize_cmf(data, png_image_size(png_ptr));
-# endif
+#endif
- png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+ if (size > 0)
+#ifdef PNG_WRITE_APNG_SUPPORTED
+ {
+ if (png_ptr->num_frames_written == 0)
+#endif
+ png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+#ifdef PNG_WRITE_APNG_SUPPORTED
+ else
+ png_write_fdAT(png_ptr, data, size);
+ }
+#endif /* PNG_WRITE_APNG_SUPPORTED */
png_ptr->mode |= PNG_HAVE_IDAT;
png_ptr->zstream.next_out = data;
continue;
}
- /* The order of these checks doesn't matter much; it just effect which
+ /* The order of these checks doesn't matter much; it just affects which
* possible error might be detected if multiple things go wrong at once.
*/
if (ret == Z_OK) /* most likely return code! */
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
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+ png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+ optimize_cmf(data, png_image_size(png_ptr));
+#endif
+
+ if (size > 0)
+#ifdef PNG_WRITE_APNG_SUPPORTED
+ {
+ if (png_ptr->num_frames_written == 0)
+#endif
+ png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+#ifdef PNG_WRITE_APNG_SUPPORTED
+ else
+ png_write_fdAT(png_ptr, data, size);
+ }
+#endif /* PNG_WRITE_APNG_SUPPORTED */
- 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_debug(1, "in png_write_IEND");
- png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
+ png_write_complete_chunk(png_ptr, png_IEND, NULL, 0);
png_ptr->mode |= PNG_HAVE_IEND;
}
/* 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);
+ png_write_complete_chunk(png_ptr, png_gAMA, buf, 4);
}
#endif
"Invalid sRGB rendering intent specified");
buf[0]=(png_byte)srgb_intent;
- png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
+ png_write_complete_chunk(png_ptr, png_sRGB, buf, 1);
}
#endif
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;
+ size_t entry_size = (spalette->depth == 8 ? 6 : 10);
+ size_t palette_size = entry_size * (size_t)spalette->nentries;
png_sPLT_entryp ep;
#ifndef PNG_POINTER_INDEXING_SUPPORTED
int i;
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, (png_bytep)new_name, (size_t)(name_len + 1));
- png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);
+ png_write_chunk_data(png_ptr, &spalette->depth, 1);
/* Loop through each palette entry, writing appropriately */
#ifdef PNG_POINTER_INDEXING_SUPPORTED
png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
{
png_byte buf[4];
- png_size_t size;
+ 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)
+ if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
{
png_byte maxbits;
size = 1;
}
- if (color_type & PNG_COLOR_MASK_ALPHA)
+ if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
{
if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
{
/* Write the chunk out as it is */
png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
- (png_size_t)num_trans);
+ (size_t)num_trans);
}
else if (color_type == PNG_COLOR_TYPE_GRAY)
{
- /* One 16 bit value */
+ /* One 16-bit value */
if (tran->gray >= (1 << png_ptr->bit_depth))
{
png_app_warning(png_ptr,
}
png_save_uint_16(buf, tran->gray);
- png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
+ png_write_complete_chunk(png_ptr, png_tRNS, buf, 2);
}
else if (color_type == PNG_COLOR_TYPE_RGB)
{
- /* Three 16 bit values */
+ /* 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]))
+ if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
#else
- if (buf[0] | buf[2] | buf[4])
+ if ((buf[0] | buf[2] | buf[4]) != 0)
#endif
{
png_app_warning(png_ptr,
- "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
+ "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);
+ png_write_complete_chunk(png_ptr, png_tRNS, buf, 6);
}
else
{
if (
#ifdef PNG_MNG_FEATURES_SUPPORTED
- (png_ptr->num_palette ||
- (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
+ (png_ptr->num_palette != 0 ||
+ (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
#endif
back->index >= png_ptr->num_palette)
{
}
buf[0] = back->index;
- png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, 1);
}
- else if (color_type & PNG_COLOR_MASK_COLOR)
+ 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]))
+ if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
#else
- if (buf[0] | buf[2] | buf[4])
+ if ((buf[0] | buf[2] | buf[4]) != 0)
#endif
{
png_warning(png_ptr,
- "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
+ "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);
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, 6);
}
else
}
png_save_uint_16(buf, back->gray);
- png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, 2);
}
}
#endif
+#ifdef PNG_WRITE_eXIf_SUPPORTED
+/* Write the Exif data */
+void /* PRIVATE */
+png_write_eXIf(png_structrp png_ptr, png_bytep exif, int num_exif)
+{
+ int i;
+ png_byte buf[1];
+
+ png_debug(1, "in png_write_eXIf");
+
+ png_write_chunk_header(png_ptr, png_eXIf, (png_uint_32)(num_exif));
+
+ for (i = 0; i < num_exif; i++)
+ {
+ buf[0] = exif[i];
+ png_write_chunk_data(png_ptr, buf, 1);
+ }
+
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
#ifdef PNG_WRITE_hIST_SUPPORTED
/* Write the histogram */
void /* PRIVATE */
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_data(png_ptr, buf, 2);
}
png_write_chunk_end(png_ptr);
/* 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)
+ size_t text_len)
{
png_uint_32 key_len;
png_byte new_key[80];
/* 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)
+ 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)
{
/* Compute the compressed data; do it now for the length */
png_text_compress_init(&comp, (png_const_bytep)text,
- text == NULL ? 0 : strlen(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);
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;
+ size_t lang_len, lang_key_len;
png_byte new_key[82];
compression_state comp;
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_data(png_ptr, (png_const_bytep)text, comp.output_len);
png_write_chunk_end(png_ptr);
}
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);
+ png_write_complete_chunk(png_ptr, png_oFFs, buf, 9);
}
#endif
#ifdef PNG_WRITE_pCAL_SUPPORTED
png_charpp params)
{
png_uint_32 purpose_len;
- png_size_t units_len, total_len;
+ size_t units_len, total_len;
png_size_tp params_len;
png_byte buf[10];
png_byte new_purpose[80];
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))));
+ (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (size_t))));
/* Find the length of each parameter, making sure we don't count the
* null terminator for the last parameter.
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);
+ png_write_chunk_data(png_ptr, buf, 10);
+ png_write_chunk_data(png_ptr, (png_const_bytep)units, (size_t)units_len);
for (i = 0; i < nparams; i++)
{
png_const_charp height)
{
png_byte buf[64];
- png_size_t wlen, hlen, total_len;
+ size_t wlen, hlen, total_len;
png_debug(1, "in png_write_sCAL_s");
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);
+ png_write_complete_chunk(png_ptr, png_pHYs, buf, 9);
}
#endif
buf[5] = mod_time->minute;
buf[6] = mod_time->second;
- png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
+ png_write_complete_chunk(png_ptr, png_tIME, buf, 7);
}
#endif
+#ifdef PNG_WRITE_APNG_SUPPORTED
+void /* PRIVATE */
+png_write_acTL(png_structp png_ptr,
+ png_uint_32 num_frames, png_uint_32 num_plays)
+{
+ png_byte buf[8];
+
+ png_debug(1, "in png_write_acTL");
+
+ png_ptr->num_frames_to_write = num_frames;
+
+ if (png_ptr->apng_flags & PNG_FIRST_FRAME_HIDDEN)
+ num_frames--;
+
+ png_save_uint_32(buf, num_frames);
+ png_save_uint_32(buf + 4, num_plays);
+
+ png_write_complete_chunk(png_ptr, png_acTL, buf, (png_size_t)8);
+}
+
+void /* PRIVATE */
+png_write_fcTL(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
+ png_uint_32 x_offset, png_uint_32 y_offset,
+ png_uint_16 delay_num, png_uint_16 delay_den, png_byte dispose_op,
+ png_byte blend_op)
+{
+ png_byte buf[26];
+
+ png_debug(1, "in png_write_fcTL");
+
+ if (png_ptr->num_frames_written == 0 && (x_offset != 0 || y_offset != 0))
+ png_error(png_ptr, "x and/or y offset for the first frame aren't 0");
+ if (png_ptr->num_frames_written == 0 &&
+ (width != png_ptr->first_frame_width ||
+ height != png_ptr->first_frame_height))
+ png_error(png_ptr, "width and/or height in the first frame's fcTL "
+ "don't match the ones in IHDR");
+
+ /* more error checking */
+ png_ensure_fcTL_is_valid(png_ptr, width, height, x_offset, y_offset,
+ delay_num, delay_den, dispose_op, blend_op);
+
+ png_save_uint_32(buf, png_ptr->next_seq_num);
+ png_save_uint_32(buf + 4, width);
+ png_save_uint_32(buf + 8, height);
+ png_save_uint_32(buf + 12, x_offset);
+ png_save_uint_32(buf + 16, y_offset);
+ png_save_uint_16(buf + 20, delay_num);
+ png_save_uint_16(buf + 22, delay_den);
+ buf[24] = dispose_op;
+ buf[25] = blend_op;
+
+ png_write_complete_chunk(png_ptr, png_fcTL, buf, (png_size_t)26);
+
+ png_ptr->next_seq_num++;
+}
+
+void /* PRIVATE */
+png_write_fdAT(png_structp png_ptr,
+ png_const_bytep data, png_size_t length)
+{
+ png_byte buf[4];
+
+ png_write_chunk_header(png_ptr, png_fdAT, (png_uint_32)(4 + length));
+
+ png_save_uint_32(buf, png_ptr->next_seq_num);
+ png_write_chunk_data(png_ptr, buf, 4);
+
+ png_write_chunk_data(png_ptr, data, length);
+
+ png_write_chunk_end(png_ptr);
+
+ png_ptr->next_seq_num++;
+}
+#endif /* PNG_WRITE_APNG_SUPPORTED */
+
/* Initializes the row writing capability of libpng */
void /* PRIVATE */
png_write_start_row(png_structrp png_ptr)
/* 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};
+ static 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};
+ static 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};
+ static 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};
+ static 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;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ png_byte filters;
+#endif
+
png_debug(1, "in png_write_start_row");
usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_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 = png_voidcast(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);
+ filters = png_ptr->do_filter;
- png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
- }
+ if (png_ptr->height == 1)
+ filters &= 0xff & ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+ if (png_ptr->width == 1)
+ filters &= 0xff & ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+ if (filters == 0)
+ filters = PNG_FILTER_NONE;
- /* 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))
+ png_ptr->do_filter = filters;
+
+ if (((filters & (PNG_FILTER_SUB | PNG_FILTER_UP | PNG_FILTER_AVG |
+ PNG_FILTER_PAETH)) != 0) && png_ptr->try_row == NULL)
{
- /* Set up previous row buffer */
- png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);
+ int num_filters = 0;
- if (png_ptr->do_filter & PNG_FILTER_UP)
- {
- png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
- png_ptr->rowbytes + 1);
+ png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
- png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
- }
+ if (filters & PNG_FILTER_SUB)
+ num_filters++;
- if (png_ptr->do_filter & PNG_FILTER_AVG)
- {
- png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
- png_ptr->rowbytes + 1);
+ if (filters & PNG_FILTER_UP)
+ num_filters++;
- png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
- }
+ if (filters & PNG_FILTER_AVG)
+ num_filters++;
- if (png_ptr->do_filter & PNG_FILTER_PAETH)
- {
- png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
- png_ptr->rowbytes + 1);
+ if (filters & PNG_FILTER_PAETH)
+ num_filters++;
- png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
- }
+ if (num_filters > 1)
+ png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr,
+ buf_size));
}
-#endif /* PNG_WRITE_FILTER_SUPPORTED */
+
+ /* We only need to keep the previous row if we are using one of the following
+ * filters.
+ */
+ if ((filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
+ png_ptr->prev_row = png_voidcast(png_bytep,
+ png_calloc(png_ptr, buf_size));
+#endif /* WRITE_FILTER */
#ifdef PNG_WRITE_INTERLACING_SUPPORTED
/* If interlaced, we need to set up width and height of pass */
- if (png_ptr->interlaced)
+ if (png_ptr->interlaced != 0)
{
- if (!(png_ptr->transformations & PNG_INTERLACE))
+ if ((png_ptr->transformations & PNG_INTERLACE) == 0)
{
png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
png_pass_ystart[0]) / png_pass_yinc[0];
/* 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};
+ static 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};
+ static 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};
+ static 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};
+ static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
#endif
png_debug(1, "in png_write_finish_row");
#ifdef PNG_WRITE_INTERLACING_SUPPORTED
/* If interlaced, go to next pass */
- if (png_ptr->interlaced)
+ if (png_ptr->interlaced != 0)
{
png_ptr->row_number = 0;
- if (png_ptr->transformations & PNG_INTERLACE)
+ if ((png_ptr->transformations & PNG_INTERLACE) != 0)
{
png_ptr->pass++;
}
png_pass_ystart[png_ptr->pass]) /
png_pass_yinc[png_ptr->pass];
- if (png_ptr->transformations & PNG_INTERLACE)
+ if ((png_ptr->transformations & PNG_INTERLACE) != 0)
break;
} while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
{
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);
+ PNG_ROWBYTES(png_ptr->usr_channels *
+ png_ptr->usr_bit_depth, png_ptr->width) + 1);
return;
}
/* 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};
+ static 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};
+ static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
png_debug(1, "in png_do_write_interlace");
{
png_bytep sp;
png_bytep dp;
- int shift;
+ unsigned int shift;
int d;
int value;
png_uint_32 i;
for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
- sp = row + (png_size_t)(i >> 3);
+ sp = row + (size_t)(i >> 3);
value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
d |= (value << shift);
{
png_bytep sp;
png_bytep dp;
- int shift;
+ unsigned int shift;
int d;
int value;
png_uint_32 i;
for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
- sp = row + (png_size_t)(i >> 2);
+ sp = row + (size_t)(i >> 2);
value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
d |= (value << shift);
{
png_bytep sp;
png_bytep dp;
- int shift;
+ unsigned int shift;
int d;
int value;
png_uint_32 i;
for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
- sp = row + (png_size_t)(i >> 1);
+ sp = row + (size_t)(i >> 1);
value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
d |= (value << shift);
png_bytep dp;
png_uint_32 i;
png_uint_32 row_width = row_info->width;
- png_size_t pixel_bytes;
+ size_t pixel_bytes;
/* Start at the beginning */
dp = row;
i += png_pass_inc[pass])
{
/* Find out where the original pixel is */
- sp = row + (png_size_t)i * pixel_bytes;
+ sp = row + (size_t)i * pixel_bytes;
/* Move the pixel */
if (dp != sp)
}
#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
+static void /* PRIVATE */
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
+ size_t row_bytes);
- /* 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)
- */
+static size_t /* PRIVATE */
+png_setup_sub_row(png_structrp png_ptr, png_uint_32 bpp,
+ size_t row_bytes, size_t lmins)
+{
+ png_bytep rp, dp, lp;
+ size_t i;
+ size_t sum = 0;
+ unsigned int v;
+ png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
- /* 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)
+ for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
+ i++, rp++, dp++)
{
- 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;
- }
+ v = *dp = *rp;
+#ifdef PNG_USE_ABS
+ sum += 128 - abs((int)v - 128);
+#else
+ sum += (v < 128) ? v : 256 - v;
#endif
- mins = sum;
}
- /* Sub filter */
- if (filter_to_do == PNG_FILTER_SUB)
- /* It's the only filter so no testing is needed */
+ for (lp = png_ptr->row_buf + 1; i < row_bytes;
+ i++, rp++, lp++, dp++)
{
- 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);
- }
+ v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+#ifdef PNG_USE_ABS
+ sum += 128 - abs((int)v - 128);
+#else
+ sum += (v < 128) ? v : 256 - v;
+#endif
- best_row = png_ptr->sub_row;
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
}
- 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;
+ return (sum);
+}
-#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;
+static void /* PRIVATE */
+png_setup_sub_row_only(png_structrp png_ptr, png_uint_32 bpp,
+ size_t row_bytes)
+{
+ png_bytep rp, dp, lp;
+ size_t i;
- 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;
+ png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
- lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
- PNG_WEIGHT_SHIFT;
- }
- }
+ for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
+ i++, rp++, dp++)
+ {
+ *dp = *rp;
+ }
- lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
- PNG_COST_SHIFT;
+ for (lp = png_ptr->row_buf + 1; i < row_bytes;
+ i++, rp++, lp++, dp++)
+ {
+ *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+ }
+}
- lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
- PNG_COST_SHIFT;
+static size_t /* PRIVATE */
+png_setup_up_row(png_structrp png_ptr, size_t row_bytes, size_t lmins)
+{
+ png_bytep rp, dp, pp;
+ size_t i;
+ size_t sum = 0;
+ unsigned int v;
- if (lmhi > PNG_HIMASK)
- lmins = PNG_MAXSUM;
+ png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
- else
- lmins = (lmhi << PNG_HISHIFT) + lmlo;
- }
+ for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+ pp = png_ptr->prev_row + 1; i < row_bytes;
+ i++, rp++, pp++, dp++)
+ {
+ v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+#ifdef PNG_USE_ABS
+ sum += 128 - abs((int)v - 128);
+#else
+ sum += (v < 128) ? v : 256 - v;
#endif
- for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
- i++, rp++, dp++)
- {
- v = *dp = *rp;
-
- sum += (v < 128) ? v : 256 - v;
- }
-
- for (lp = row_buf + 1; i < row_bytes;
- i++, rp++, lp++, dp++)
- {
- v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
-
- sum += (v < 128) ? v : 256 - v;
-
- if (sum > lmins) /* We are already worse, don't continue. */
- break;
- }
+ if (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;
+ return (sum);
+}
+static void /* PRIVATE */
+png_setup_up_row_only(png_structrp png_ptr, size_t row_bytes)
+{
+ png_bytep rp, dp, pp;
+ size_t i;
- 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;
+ png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
- sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
- PNG_WEIGHT_SHIFT;
- }
- }
+ for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+ pp = png_ptr->prev_row + 1; i < row_bytes;
+ i++, rp++, pp++, dp++)
+ {
+ *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ }
+}
- sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
- PNG_COST_SHIFT;
+static size_t /* PRIVATE */
+png_setup_avg_row(png_structrp png_ptr, png_uint_32 bpp,
+ size_t row_bytes, size_t lmins)
+{
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 i;
+ size_t sum = 0;
+ unsigned int v;
- sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
- PNG_COST_SHIFT;
+ png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
- if (sumhi > PNG_HIMASK)
- sum = PNG_MAXSUM;
+ for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+ pp = png_ptr->prev_row + 1; i < bpp; i++)
+ {
+ v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
- else
- sum = (sumhi << PNG_HISHIFT) + sumlo;
- }
+#ifdef PNG_USE_ABS
+ sum += 128 - abs((int)v - 128);
+#else
+ sum += (v < 128) ? v : 256 - v;
#endif
-
- if (sum < mins)
- {
- mins = sum;
- best_row = png_ptr->sub_row;
- }
}
- /* Up filter */
- if (filter_to_do == PNG_FILTER_UP)
+ for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
{
- png_bytep rp, dp, pp;
- png_size_t i;
+ v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+ & 0xff);
- 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);
- }
+#ifdef PNG_USE_ABS
+ sum += 128 - abs((int)v - 128);
+#else
+ sum += (v < 128) ? v : 256 - v;
+#endif
- best_row = png_ptr->up_row;
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
}
- 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;
-
+ return (sum);
+}
+static void /* PRIVATE */
+png_setup_avg_row_only(png_structrp png_ptr, png_uint_32 bpp,
+ size_t row_bytes)
+{
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 i;
-#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;
+ png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
- 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;
+ for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+ pp = png_ptr->prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+ }
- lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
- PNG_WEIGHT_SHIFT;
- }
- }
+ for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+ & 0xff);
+ }
+}
- lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
- PNG_COST_SHIFT;
+static size_t /* PRIVATE */
+png_setup_paeth_row(png_structrp png_ptr, png_uint_32 bpp,
+ size_t row_bytes, size_t lmins)
+{
+ png_bytep rp, dp, pp, cp, lp;
+ size_t i;
+ size_t sum = 0;
+ unsigned int v;
- lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
- PNG_COST_SHIFT;
+ png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
- if (lmhi > PNG_HIMASK)
- lmins = PNG_MAXSUM;
+ for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+ pp = png_ptr->prev_row + 1; i < bpp; i++)
+ {
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
- else
- lmins = (lmhi << PNG_HISHIFT) + lmlo;
- }
+#ifdef PNG_USE_ABS
+ sum += 128 - abs((int)v - 128);
+#else
+ sum += (v < 128) ? v : 256 - v;
#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 (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
+ i++)
+ {
+ int a, b, c, pa, pb, pc, p;
- 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;
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
- sumhi = (sumhi * png_ptr->filter_weights[j]) >>
- PNG_WEIGHT_SHIFT;
- }
- }
+ p = b - c;
+ pc = a - c;
- sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
- PNG_COST_SHIFT;
+#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
- sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
- PNG_COST_SHIFT;
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
- if (sumhi > PNG_HIMASK)
- sum = PNG_MAXSUM;
+ v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
- else
- sum = (sumhi << PNG_HISHIFT) + sumlo;
- }
+#ifdef PNG_USE_ABS
+ sum += 128 - abs((int)v - 128);
+#else
+ sum += (v < 128) ? v : 256 - v;
#endif
- if (sum < mins)
- {
- mins = sum;
- best_row = png_ptr->up_row;
- }
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
}
- /* Avg filter */
- if (filter_to_do == PNG_FILTER_AVG)
- {
- png_bytep rp, dp, pp, lp;
- png_uint_32 i;
+ return (sum);
+}
+static void /* PRIVATE */
+png_setup_paeth_row_only(png_structrp png_ptr, png_uint_32 bpp,
+ size_t row_bytes)
+{
+ png_bytep rp, dp, pp, cp, lp;
+ size_t 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);
- }
+ png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
- 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;
+ for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+ pp = png_ptr->prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
}
- else if (filter_to_do & PNG_FILTER_AVG)
+ for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
+ i++)
{
- 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;
+ int a, b, c, pa, pb, pc, p;
- lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
- PNG_COST_SHIFT;
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
- if (lmhi > PNG_HIMASK)
- lmins = PNG_MAXSUM;
+ p = b - c;
+ pc = a - c;
- else
- lmins = (lmhi << PNG_HISHIFT) + lmlo;
- }
+#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
- 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);
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
- 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;
- }
+ *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+ }
+}
+#endif /* WRITE_FILTER */
-#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;
+void /* PRIVATE */
+png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
+{
+#ifndef PNG_WRITE_FILTER_SUPPORTED
+ png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
+#else
+ unsigned int filter_to_do = png_ptr->do_filter;
+ png_bytep row_buf;
+ png_bytep best_row;
+ png_uint_32 bpp;
+ size_t mins;
+ size_t row_bytes = row_info->rowbytes;
- 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;
+ png_debug(1, "in png_write_find_filter");
- sumhi = (sumhi * png_ptr->filter_weights[j]) >>
- PNG_WEIGHT_SHIFT;
- }
- }
+ /* Find out how many bytes offset each pixel is */
+ bpp = (row_info->pixel_depth + 7) >> 3;
- sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
- PNG_COST_SHIFT;
+ row_buf = png_ptr->row_buf;
+ mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the
+ running sum */;
- sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
- PNG_COST_SHIFT;
+ /* 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)
+ */
- if (sumhi > PNG_HIMASK)
- sum = PNG_MAXSUM;
- else
- sum = (sumhi << PNG_HISHIFT) + sumlo;
- }
-#endif
+ /* 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.
+ */
+ best_row = png_ptr->row_buf;
- if (sum < mins)
- {
- mins = sum;
- best_row = png_ptr->avg_row;
- }
+ if (PNG_SIZE_MAX/128 <= row_bytes)
+ {
+ /* Overflow can occur in the calculation, just select the lowest set
+ * filter.
+ */
+ filter_to_do &= 0U-filter_to_do;
}
-
- /* Paeth filter */
- if (filter_to_do == PNG_FILTER_PAETH)
+ else if ((filter_to_do & PNG_FILTER_NONE) != 0 &&
+ filter_to_do != PNG_FILTER_NONE)
{
- 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);
- }
+ /* Overflow not possible and multiple filters in the list, including the
+ * 'none' filter.
+ */
+ png_bytep rp;
+ size_t sum = 0;
+ size_t i;
+ unsigned int 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++;
-
- p = b - c;
- pc = a - c;
-
+ for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+ {
+ v = *rp;
#ifdef PNG_USE_ABS
- pa = abs(p);
- pb = abs(pc);
- pc = abs(p + pc);
+ sum += 128 - abs((int)v - 128);
#else
- pa = p < 0 ? -p : p;
- pb = pc < 0 ? -pc : pc;
- pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+ sum += (v < 128) ? v : 256 - v;
#endif
+ }
+ }
- p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+ mins = sum;
+ }
- *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
- }
- best_row = png_ptr->paeth_row;
+ /* Sub filter */
+ if (filter_to_do == PNG_FILTER_SUB)
+ /* It's the only filter so no testing is needed */
+ {
+ png_setup_sub_row_only(png_ptr, bpp, row_bytes);
+ best_row = png_ptr->try_row;
}
- else if (filter_to_do & PNG_FILTER_PAETH)
+ else if ((filter_to_do & PNG_FILTER_SUB) != 0)
{
- png_bytep rp, dp, pp, cp, lp;
- png_uint_32 sum = 0, lmins = mins;
- png_size_t i;
- int v;
+ size_t sum;
+ size_t lmins = mins;
-#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;
+ sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins);
- for (j = 0; j < num_p_filters; j++)
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->try_row;
+ if (png_ptr->tst_row != NULL)
{
- 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;
- }
+ png_ptr->try_row = png_ptr->tst_row;
+ png_ptr->tst_row = best_row;
}
+ }
+ }
- 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;
+ /* Up filter */
+ if (filter_to_do == PNG_FILTER_UP)
+ {
+ png_setup_up_row_only(png_ptr, row_bytes);
+ best_row = png_ptr->try_row;
+ }
- if (lmhi > PNG_HIMASK)
- lmins = PNG_MAXSUM;
+ else if ((filter_to_do & PNG_FILTER_UP) != 0)
+ {
+ size_t sum;
+ size_t lmins = mins;
- else
- lmins = (lmhi << PNG_HISHIFT) + lmlo;
- }
-#endif
+ sum = png_setup_up_row(png_ptr, row_bytes, lmins);
- for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
- pp = prev_row + 1; i < bpp; i++)
+ if (sum < mins)
{
- v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
-
- sum += (v < 128) ? v : 256 - v;
+ mins = sum;
+ best_row = png_ptr->try_row;
+ if (png_ptr->tst_row != NULL)
+ {
+ png_ptr->try_row = png_ptr->tst_row;
+ png_ptr->tst_row = best_row;
+ }
}
+ }
- 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);
+ /* Avg filter */
+ if (filter_to_do == PNG_FILTER_AVG)
+ {
+ png_setup_avg_row_only(png_ptr, bpp, row_bytes);
+ best_row = png_ptr->try_row;
+ }
- sum += (v < 128) ? v : 256 - v;
+ else if ((filter_to_do & PNG_FILTER_AVG) != 0)
+ {
+ size_t sum;
+ size_t lmins = mins;
- if (sum > lmins) /* We are already worse, don't continue. */
- break;
- }
+ sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins);
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
- if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ if (sum < mins)
{
- 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++)
+ mins = sum;
+ best_row = png_ptr->try_row;
+ if (png_ptr->tst_row != NULL)
{
- 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;
- }
+ png_ptr->try_row = png_ptr->tst_row;
+ png_ptr->tst_row = best_row;
}
+ }
+ }
- 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;
+ /* Paeth filter */
+ if (filter_to_do == PNG_FILTER_PAETH)
+ {
+ png_setup_paeth_row_only(png_ptr, bpp, row_bytes);
+ best_row = png_ptr->try_row;
+ }
- if (sumhi > PNG_HIMASK)
- sum = PNG_MAXSUM;
+ else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
+ {
+ size_t sum;
+ size_t lmins = mins;
- else
- sum = (sumhi << PNG_HISHIFT) + sumlo;
- }
-#endif
+ sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
if (sum < mins)
{
- best_row = png_ptr->paeth_row;
+ best_row = png_ptr->try_row;
+ if (png_ptr->tst_row != NULL)
+ {
+ png_ptr->try_row = png_ptr->tst_row;
+ png_ptr->tst_row = best_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 */
+#endif /* WRITE_FILTER */
}
/* 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*/)
+ size_t full_row_length/*includes filter byte*/)
{
png_debug(1, "in png_write_filtered_row");
png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
+#ifdef PNG_WRITE_FILTER_SUPPORTED
/* Swap the current and previous rows */
if (png_ptr->prev_row != NULL)
{
png_ptr->prev_row = png_ptr->row_buf;
png_ptr->row_buf = tptr;
}
+#endif /* WRITE_FILTER */
/* Finish row - updates counters and flushes zlib if last row */
png_write_finish_row(png_ptr);
{
png_write_flush(png_ptr);
}
-#endif
+#endif /* WRITE_FLUSH */
+}
+
+#ifdef PNG_WRITE_APNG_SUPPORTED
+void /* PRIVATE */
+png_write_reset(png_structp png_ptr)
+{
+ png_ptr->row_number = 0;
+ png_ptr->pass = 0;
+ png_ptr->mode &= ~PNG_HAVE_IDAT;
+}
+
+void /* PRIVATE */
+png_write_reinit(png_structp png_ptr, png_infop info_ptr,
+ png_uint_32 width, png_uint_32 height)
+{
+ if (png_ptr->num_frames_written == 0 &&
+ (width != png_ptr->first_frame_width ||
+ height != png_ptr->first_frame_height))
+ png_error(png_ptr, "width and/or height in the first frame's fcTL "
+ "don't match the ones in IHDR");
+ if (width > png_ptr->first_frame_width ||
+ height > png_ptr->first_frame_height)
+ png_error(png_ptr, "width and/or height for a frame greater than"
+ "the ones in IHDR");
+
+ png_set_IHDR(png_ptr, info_ptr, width, height,
+ info_ptr->bit_depth, info_ptr->color_type,
+ info_ptr->interlace_type, info_ptr->compression_type,
+ info_ptr->filter_type);
+
+ png_ptr->width = width;
+ png_ptr->height = height;
+ png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
+ png_ptr->usr_width = png_ptr->width;
}
-#endif /* PNG_WRITE_SUPPORTED */
+#endif /* PNG_WRITE_APNG_SUPPORTED */
+#endif /* WRITE */
projects / platform / upstream / libpng.git / blobdiff