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[libpng17] Combined sub_row, up_row, avg_row, and paeth_row buffers into a

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single try_row buffer and in cases where two or more of those are
being tested, a second tst_row buffer.  This improves CPU speed
over that achieved by libpng-1.7.0beta49.
This commit is contained in:
Glenn Randers-Pehrson 2015-02-15 12:44:16 -06:00
parent 7e56f5858d
commit f1e4acb5b1
5 changed files with 110 additions and 83 deletions
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8
ANNOUNCE
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@ -1,5 +1,5 @@
Libpng 1.7.0beta50 - February 11, 2015
Libpng 1.7.0beta50 - February 15, 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.
@ -708,7 +708,11 @@ Version 1.7.0beta49 [February 11, 2015]
Consolidated redundant code in pngwutil.c
Deal with integer overflow of sum in pngwutil.c
Version 1.7.0beta50 [February 11, 2015]
Version 1.7.0beta50 [February 15, 2015]
Combined sub_row, up_row, avg_row, and paeth_row buffers into a
single try_row buffer and in cases where two or more of those are
being tested, a second tst_row buffer. This improves CPU speed
over that achieved by libpng-1.7.0beta49.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

6
CHANGES
View File

@ -4997,7 +4997,11 @@ Version 1.7.0beta49 [February 11, 2015]
Consolidated redundant code in pngwutil.c
Deal with integer overflow of sum in pngwutil.c
Version 1.7.0beta50 [February 11, 2015]
Version 1.7.0beta50 [February 15, 2015]
Combined sub_row, up_row, avg_row, and paeth_row buffers into a
single try_row buffer and in cases where two or more of those are
being tested, a second tst_row buffer. This improves CPU speed
over that achieved by libpng-1.7.0beta49.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

5
pngstruct.h
View File

@ -341,8 +341,9 @@ struct png_struct_def
size_t big_row_buf_size; /* Actual size of both */
#endif
#ifdef PNG_WRITE_SUPPORTED
png_bytep try_row; /* buffer to save trial 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
/* UNKNOWN CHUNK HANDLING */

2
pngwrite.c
View File

@ -943,8 +943,10 @@ png_write_destroy(png_structrp png_ptr)
#ifdef PNG_WRITE_FILTER_SUPPORTED
png_free(png_ptr, png_ptr->prev_row);
png_free(png_ptr, png_ptr->try_row);
png_free(png_ptr, png_ptr->tst_row);
png_ptr->prev_row = NULL;
png_ptr->try_row = NULL;
png_ptr->tst_row = NULL;
#endif
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

172
pngwutil.c
View File

@ -1957,7 +1957,24 @@ png_write_alloc_filter_row_buffers(png_structrp png_ptr, int 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));
}
}
#endif /* WRITE_FILTER */
@ -2353,20 +2370,19 @@ png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
for (lp = png_ptr->row_buf + 1; i < row_bytes;
i++, rp++, lp++, dp++)
{
png_size_t old_sum = sum;
v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
sum += (v < 128) ? v : 256 - v;
if (lmins != PNG_SIZE_MAX)
if (sum < old_sum) /* overflow happened */
{
png_size_t old_sum = sum;
sum += (v < 128) ? v : 256 - v;
if (sum < old_sum) /* overflow happened */
return (PNG_SIZE_MAX - 1);
if (sum > lmins) /* We are already worse, don't continue. */
break;
sum = PNG_SIZE_MAX - 1;
break;
}
if (sum > lmins) /* We are already worse, don't continue. */
break;
}
return (sum);
@ -2385,19 +2401,19 @@ png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
pp = png_ptr->prev_row + 1; i < row_bytes;
i++, rp++, pp++, dp++)
{
png_size_t old_sum = sum;
v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
if (lmins != PNG_SIZE_MAX)
sum += (v < 128) ? v : 256 - v;
if (sum < old_sum) /* overflow happened */
{
png_size_t old_sum = sum;
sum += (v < 128) ? v : 256 - v;
if (sum < old_sum) /* overflow happened */
return (PNG_SIZE_MAX - 1);
if (sum > lmins) /* We are already worse, don't continue. */
break;
sum = PNG_SIZE_MAX - 1;
break;
}
if (sum > lmins) /* We are already worse, don't continue. */
break;
}
return (sum);
@ -2422,21 +2438,21 @@ png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
{
png_size_t old_sum = sum;
v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
& 0xff);
if (lmins != PNG_SIZE_MAX)
sum += (v < 128) ? v : 256 - v;
if (sum < old_sum) /* overflow happened */
{
png_size_t old_sum = sum;
sum += (v < 128) ? v : 256 - v;
if (sum < old_sum) /* overflow happened */
return (PNG_SIZE_MAX - 1);
if (sum > lmins) /* We are already worse, don't continue. */
break;
sum = PNG_SIZE_MAX - 1;
break;
}
if (sum > lmins) /* We are already worse, don't continue. */
break;
}
return (sum);
@ -2463,6 +2479,7 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
i++)
{
int a, b, c, pa, pb, pc, p;
png_size_t old_sum = sum;
b = *pp++;
c = *cp++;
@ -2485,18 +2502,16 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
if (lmins != PNG_SIZE_MAX)
sum += (v < 128) ? v : 256 - v;
if (sum < old_sum) /* overflow happened */
{
png_size_t old_sum = sum;
sum += (v < 128) ? v : 256 - v;
if (sum < old_sum) /* overflow happened */
return (PNG_SIZE_MAX - 1);
if (sum > lmins) /* We are already worse, don't continue. */
break;
sum = PNG_SIZE_MAX - 1;
break;
}
if (sum > lmins) /* We are already worse, don't continue. */
break;
}
return (sum);
@ -2516,9 +2531,9 @@ 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
png_byte best_filter_value = PNG_FILTER_VALUE_NONE;
png_byte filter_to_do = png_ptr->do_filter;
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;
@ -2570,6 +2585,8 @@ 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;
@ -2623,6 +2640,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
}
#endif
mins = sum;
best_row = png_ptr->row_buf;
}
/* Sub filter */
@ -2630,8 +2648,8 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
/* It's the only filter so no testing is needed */
{
png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
(void) png_setup_sub_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
best_filter_value = PNG_FILTER_VALUE_SUB;
(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)
@ -2718,7 +2736,12 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (sum < mins)
{
mins = sum;
best_filter_value = PNG_FILTER_VALUE_SUB;
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;
}
}
}
@ -2726,8 +2749,8 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (filter_to_do == PNG_FILTER_UP)
{
png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
(void) png_setup_up_row(png_ptr, row_bytes, PNG_SIZE_MAX);
best_filter_value = PNG_FILTER_VALUE_UP;
(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)
@ -2810,7 +2833,12 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (sum < mins)
{
mins = sum;
best_filter_value = PNG_FILTER_VALUE_UP;
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;
}
}
}
@ -2818,8 +2846,8 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (filter_to_do == PNG_FILTER_AVG)
{
png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
(void) png_setup_avg_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
best_filter_value = PNG_FILTER_VALUE_AVG;
(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)
@ -2901,7 +2929,12 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (sum < mins)
{
mins = sum;
best_filter_value = PNG_FILTER_VALUE_AVG;
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;
}
}
}
@ -2909,8 +2942,8 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if ((filter_to_do == PNG_FILTER_PAETH) != 0)
{
png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
(void) png_setup_paeth_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
best_filter_value = PNG_FILTER_VALUE_PAETH;
(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)
@ -2991,35 +3024,18 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
if (sum < mins)
{
best_filter_value = PNG_FILTER_VALUE_PAETH;
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;
}
}
}
/* Do the actual writing of the filtered row data from the chosen filter. */
if (best_filter_value == PNG_FILTER_VALUE_NONE)
png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
else
{
if (best_filter_value != png_ptr->try_row[0])
{
png_ptr->try_row[0] = best_filter_value;
if (best_filter_value == PNG_FILTER_VALUE_SUB)
(void) png_setup_sub_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
if (best_filter_value == PNG_FILTER_VALUE_UP)
(void) png_setup_up_row(png_ptr, row_bytes, PNG_SIZE_MAX);
if (best_filter_value == PNG_FILTER_VALUE_AVG)
(void) png_setup_avg_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
if (best_filter_value == PNG_FILTER_VALUE_PAETH)
(void) png_setup_paeth_row(png_ptr, bpp, row_bytes, PNG_SIZE_MAX);
}
png_write_filtered_row(png_ptr, png_ptr->try_row, row_info->rowbytes+1);
}
png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
/* Save the type of filter we picked this time for future calculations */
@ -3032,7 +3048,7 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
}
png_ptr->prev_filters[j] = best_filter_value;
png_ptr->prev_filters[j] = best_row[0];
}
#endif /* WRITE_WEIGHTED_FILTER */
#endif /* WRITE_FILTER */