cheng/libpng
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[libpng16] Backported filter selection code from libpng-1.7.0beta51, to combine

Browse Source 
sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
This commit is contained in:
Glenn Randers-Pehrson 2015-05-30 11:54:45 -05:00
parent 9fbdce8fb5
commit e6877671f1
5 changed files with 403 additions and 464 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
ANNOUNCE
View File

@ -1,4 +1,4 @@
Libpng 1.6.18beta05 - May 29, 2015
Libpng 1.6.18beta05 - May 30, 2015
This is not intended to be a public release. It will be replaced
within a few weeks by a public version or by another test version.
@ -51,9 +51,12 @@ Version 1.6.18beta04 [May 20, 2015]
type and can be defined on the command line, allowing testing in beta
builds (John Bowler).
Avoid Coverity issue 80858 (REVERSE NULL) in pngtest.c
Avoid a harmless potential integer overflow in png_XYZ_from_xy().
Avoid a harmless potential integer overflow in png_XYZ_from_xy() (Bug
report from Christopher Ferris).
Version 1.6.18beta05 [May 29, 2015]
Version 1.6.18beta05 [May 30, 2015]
Backport filter selection code from libpng-1.7.0beta51, to combine
sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

4
CHANGES
View File

@ -5239,7 +5239,9 @@ Version 1.6.18beta04 [May 20, 2015]
Avoid a harmless potential integer overflow in png_XYZ_from_xy() (Bug
report from Christopher Ferris).
Version 1.6.18beta05 [May 29, 2015]
Version 1.6.18beta05 [May 30, 2015]
Backport filter selection code from libpng-1.7.0beta51, to combine
sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

16
pngstruct.h
View File

@ -219,16 +219,18 @@ struct png_struct_def
png_uint_32 row_number; /* current row in interlace pass */
png_uint_32 chunk_name; /* PNG_CHUNK() id of current chunk */
png_bytep prev_row; /* buffer to save previous (unfiltered) row.
* This is a pointer into big_prev_row
* While reading this is a pointer into
* big_prev_row; while writing it is separately
* allocated if needed.
*/
png_bytep row_buf; /* buffer to save current (unfiltered) row.
* This is a pointer into big_row_buf
* While reading, this is a pointer into
* big_row_buf; while writing it is separately
* allocated.
*/
#ifdef PNG_WRITE_SUPPORTED
png_bytep sub_row; /* buffer to save "sub" row when filtering */
png_bytep up_row; /* buffer to save "up" row when filtering */
png_bytep avg_row; /* buffer to save "avg" row when filtering */
png_bytep paeth_row; /* buffer to save "Paeth" row when filtering */
#ifdef PNG_WRITE_FILTER_SUPPORTED
png_bytep try_row; /* buffer to save trial row when filtering */
png_bytep tst_row; /* buffer to save best trial row when filtering */
#endif
png_size_t info_rowbytes; /* Added in 1.5.4: cache of updated row bytes */

124
pngwrite.c
View File

@ -942,15 +942,11 @@ png_write_destroy(png_structrp png_ptr)
png_ptr->row_buf = NULL;
#ifdef PNG_WRITE_FILTER_SUPPORTED
png_free(png_ptr, png_ptr->prev_row);
png_free(png_ptr, png_ptr->sub_row);
png_free(png_ptr, png_ptr->up_row);
png_free(png_ptr, png_ptr->avg_row);
png_free(png_ptr, png_ptr->paeth_row);
png_free(png_ptr, png_ptr->try_row);
png_free(png_ptr, png_ptr->tst_row);
png_ptr->prev_row = NULL;
png_ptr->sub_row = NULL;
png_ptr->up_row = NULL;
png_ptr->avg_row = NULL;
png_ptr->paeth_row = NULL;
png_ptr->try_row = NULL;
png_ptr->tst_row = NULL;
#endif
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
@ -1057,75 +1053,67 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
* wants to start and stop using particular filters during compression,
* it should start out with all of the filters, and then remove them
* or add them back after the start of compression.
*
* NOTE: this is a nasty constraint on the code, because it means that the
* prev_row buffer must be maintained even if there are currently no
* 'prev_row' requiring filters active.
*/
if (png_ptr->row_buf != NULL)
{
#ifdef PNG_WRITE_FILTER_SUPPORTED
if ((png_ptr->do_filter & PNG_FILTER_SUB) != 0 &&
png_ptr->sub_row == NULL)
int num_filters;
png_alloc_size_t buf_size;
/* Repeat the checks in png_write_start_row; 1 pixel high or wide
* images cannot benefit from certain filters. If this isn't done here
* the check below will fire on 1 pixel high images.
*/
if (png_ptr->height == 1)
filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
if (png_ptr->width == 1)
filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
&& png_ptr->prev_row == NULL)
{
png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
(png_ptr->rowbytes + 1));
png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
/* This is the error case, however it is benign - the previous row
* is not available so the filter can't be used. Just warn here.
*/
png_app_warning(png_ptr,
"png_set_filter: UP/AVG/PAETH cannot be added after start");
filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
}
if ((png_ptr->do_filter & PNG_FILTER_UP) != 0 &&
png_ptr->up_row == NULL)
num_filters = 0;
if (filters & PNG_FILTER_SUB)
num_filters++;
if (filters & PNG_FILTER_UP)
num_filters++;
if (filters & PNG_FILTER_AVG)
num_filters++;
if (filters & PNG_FILTER_PAETH)
num_filters++;
/* Allocate needed row buffers if they have not already been
* allocated.
*/
buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
png_ptr->width) + 1;
if (png_ptr->try_row == NULL)
png_ptr->try_row = png_malloc(png_ptr, buf_size);
if (num_filters > 1)
{
if (png_ptr->prev_row == NULL)
{
png_warning(png_ptr, "Can't add Up filter after starting");
png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
~PNG_FILTER_UP);
}
else
{
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->tst_row == NULL)
png_ptr->tst_row = png_malloc(png_ptr, buf_size);
}
if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0 &&
png_ptr->avg_row == NULL)
{
if (png_ptr->prev_row == NULL)
{
png_warning(png_ptr, "Can't add Average filter after starting");
png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
~PNG_FILTER_AVG);
}
else
{
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) != 0 &&
png_ptr->paeth_row == NULL)
{
if (png_ptr->prev_row == NULL)
{
png_warning(png_ptr, "Can't add Paeth filter after starting");
png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
}
else
{
png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
(png_ptr->rowbytes + 1));
png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
}
}
if (png_ptr->do_filter == PNG_NO_FILTERS)
#endif /* WRITE_FILTER */
png_ptr->do_filter = PNG_FILTER_NONE;
}
png_ptr->do_filter = (png_byte)filters;
}
else
png_error(png_ptr, "Unknown custom filter method");

714
pngwutil.c
View File

@ -1961,6 +1961,10 @@ png_write_start_row(png_structrp png_ptr)
png_alloc_size_t buf_size;
int usr_pixel_depth;
#ifdef PNG_WRITE_FILTER_SUPPORTED
int filters;
#endif
png_debug(1, "in png_write_start_row");
usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
@ -1971,50 +1975,53 @@ png_write_start_row(png_structrp png_ptr)
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 &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
if (png_ptr->width == 1)
filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
if (filters == 0)
filters = PNG_FILTER_NONE;
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)
{
int num_filters = 0;
png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
if (filters & PNG_FILTER_SUB)
num_filters++;
if (filters & PNG_FILTER_UP)
num_filters++;
if (filters & PNG_FILTER_AVG)
num_filters++;
if (filters & PNG_FILTER_PAETH)
num_filters++;
if (num_filters > 1)
png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr,
buf_size));
}
/* 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)) != 0)
{
/* 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) != 0)
{
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) != 0)
{
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) != 0)
{
png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
png_ptr->rowbytes + 1);
png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
}
}
/* 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_calloc(png_ptr, buf_size);
#endif /* WRITE_FILTER */
#ifdef PNG_WRITE_INTERLACING_SUPPORTED
@ -2310,6 +2317,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
}
#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.
@ -2318,42 +2326,232 @@ static void /* PRIVATE */
png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
png_size_t row_bytes);
#ifdef PNG_WRITE_FILTER_SUPPORTED
static png_size_t /* PRIVATE */
png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
const png_size_t row_bytes, const png_size_t lmins)
{
png_bytep rp, dp, lp;
png_size_t i;
png_size_t sum = 0;
int v;
png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
i++, rp++, dp++)
{
v = *dp = *rp;
sum += (v < 128) ? v : 256 - v;
}
for (lp = png_ptr->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;
}
return (sum);
}
static png_size_t /* PRIVATE */
png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
const png_size_t lmins)
{
png_bytep rp, dp, pp;
png_size_t i;
png_size_t sum = 0;
int v;
png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
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);
sum += (v < 128) ? v : 256 - v;
if (sum > lmins) /* We are already worse, don't continue. */
break;
}
return (sum);
}
static png_size_t /* PRIVATE */
png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
const png_size_t row_bytes, const png_size_t lmins)
{
png_bytep rp, dp, pp, lp;
png_uint_32 i;
png_size_t sum = 0;
int v;
png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
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);
sum += (v < 128) ? v : 256 - v;
}
for (lp = png_ptr->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;
}
return (sum);
}
static png_size_t /* PRIVATE */
png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
const png_size_t row_bytes, const png_size_t lmins)
{
png_bytep rp, dp, pp, cp, lp;
png_size_t i;
png_size_t sum = 0;
int v;
png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
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);
sum += (v < 128) ? v : 256 - v;
}
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;
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;
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;
}
return (sum);
}
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
#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))
static png_size_t /* PRIVATE */
png_increase_lmins(png_structrp png_ptr, png_size_t lmins)
{
/* 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.
*/
int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
for (j = 0; j < png_ptr->num_prev_filters; j++)
{
if (png_ptr->prev_filters[j] == png_ptr->try_row[0])
{
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_ptr->try_row[0]]) >>
PNG_COST_SHIFT;
lmhi = (lmhi * png_ptr->inv_filter_costs[png_ptr->try_row[0]]) >>
PNG_COST_SHIFT;
if (lmhi > PNG_HIMASK)
lmins = PNG_MAXSUM;
else
lmins = (lmhi << PNG_HISHIFT) + lmlo;
return (lmins);
}
#endif /* WRITE_WEIGHTED_FILTER */
#endif /* WRITE_FILTER */
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;
#ifndef PNG_WRITE_FILTER_SUPPORTED
png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
#else
png_byte filter_to_do = png_ptr->do_filter;
png_size_t row_bytes = row_info->rowbytes;
png_bytep row_buf;
png_bytep best_row;
png_uint_32 bpp;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
int num_p_filters = png_ptr->num_prev_filters;
#endif
png_size_t mins;
png_size_t row_bytes = row_info->rowbytes;
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)
{
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;
row_buf = png_ptr->row_buf;
mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the
running sum */;
/* The prediction method we use is to find which method provides the
* smallest value when summing the absolute values of the distances
@ -2383,19 +2581,16 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
/* 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 ((filter_to_do & PNG_FILTER_NONE) != 0 && filter_to_do != PNG_FILTER_NONE)
{
png_bytep rp;
png_uint_32 sum = 0;
png_size_t 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)
{
@ -2434,6 +2629,28 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
sum = (sumhi << PNG_HISHIFT) + sumlo;
}
#endif
if (PNG_SIZE_MAX/128 <= row_bytes)
{
for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
{
/* Check for overflow */
if (sum > PNG_SIZE_MAX/128 - 256)
break;
v = *rp;
sum += (v < 128) ? v : 256 - v;
}
}
else /* Overflow is not possible */
{
for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
{
v = *rp;
sum += (v < 128) ? v : 256 - v;
}
}
mins = sum;
}
@ -2441,87 +2658,21 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
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);
}
best_row = png_ptr->sub_row;
(void) png_setup_sub_row(png_ptr, bpp, row_bytes, mins);
best_row = png_ptr->try_row;
}
else if ((filter_to_do & PNG_FILTER_SUB) != 0)
{
png_bytep rp, dp, lp;
png_uint_32 sum = 0, lmins = mins;
png_size_t i;
int v;
png_size_t sum;
png_size_t lmins = mins;
#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.
*/
png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
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;
}
lmins = png_increase_lmins(png_ptr, lmins);
#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);
sum += (v < 128) ? v : 256 - v;
if (sum > lmins) /* We are already worse, don't continue. */
break;
}
sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins);
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
@ -2560,78 +2711,33 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (sum < mins)
{
mins = sum;
best_row = png_ptr->sub_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;
}
}
}
/* 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);
}
best_row = png_ptr->up_row;
(void) png_setup_up_row(png_ptr, row_bytes, mins);
best_row = png_ptr->try_row;
}
else if ((filter_to_do & PNG_FILTER_UP) != 0)
{
png_bytep rp, dp, pp;
png_uint_32 sum = 0, lmins = mins;
png_size_t i;
int v;
png_size_t sum;
png_size_t lmins = mins;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
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;
}
lmins = png_increase_lmins(png_ptr, lmins);
#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++);
sum += (v < 128) ? v : 256 - v;
if (sum > lmins) /* We are already worse, don't continue. */
break;
}
sum = png_setup_up_row(png_ptr, row_bytes, lmins);
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
@ -2670,89 +2776,33 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (sum < mins)
{
mins = sum;
best_row = png_ptr->up_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;
}
}
}
/* 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));
}
for (lp = row_buf + 1; i < row_bytes; i++)
{
*dp++ =
(png_byte)((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2));
}
best_row = png_ptr->avg_row;
(void) png_setup_avg_row(png_ptr, bpp, row_bytes, mins);
best_row = png_ptr->try_row;
}
else if ((filter_to_do & PNG_FILTER_AVG) != 0)
{
png_bytep rp, dp, pp, lp;
png_uint_32 sum = 0, lmins = mins;
png_size_t i;
int v;
png_size_t sum;
png_size_t lmins = mins;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
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;
}
lmins = png_increase_lmins(png_ptr, lmins);
#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));
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));
sum += (v < 128) ? v : 256 - v;
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)
@ -2791,143 +2841,33 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (sum < mins)
{
mins = sum;
best_row = png_ptr->avg_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;
}
}
}
/* Paeth filter */
if ((filter_to_do == PNG_FILTER_PAETH) != 0)
{
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++);
}
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);
}
best_row = png_ptr->paeth_row;
(void) png_setup_paeth_row(png_ptr, bpp, row_bytes, mins);
best_row = png_ptr->try_row;
}
else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
{
png_bytep rp, dp, pp, cp, lp;
png_uint_32 sum = 0, lmins = mins;
png_size_t i;
int v;
png_size_t sum;
png_size_t lmins = mins;
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
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;
}
lmins = png_increase_lmins(png_ptr, lmins);
#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++);
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 /* 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 /* SLOW_PAETH */
v = *dp++ = (png_byte)((int)*rp++ - p);
sum += (v < 128) ? v : 256 - v;
if (sum > lmins) /* We are already worse, don't continue. */
break;
}
sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
@ -2965,15 +2905,19 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (sum < mins)
{
best_row = png_ptr->paeth_row;
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;
}
}
}
#endif /* WRITE_FILTER */
/* 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)
@ -2987,7 +2931,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
png_ptr->prev_filters[j] = best_row[0];
}
#endif
#endif /* WRITE_WEIGHTED_FILTER */
#endif /* WRITE_FILTER */
}