Imported from libpng-1.0.1b.tar
diff --git a/pngwutil.c b/pngwutil.c
index 8d56232..5355bfb 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,12 +1,12 @@
/* pngwutil.c - utilities to write a PNG file
*
- * libpng 1.0.1a
+ * 1.0.1b
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
* Copyright (c) 1996, 1997 Andreas Dilger
* Copyright (c) 1998, Glenn Randers-Pehrson
- * April 21, 1998
+ * May 2, 1998
*/
#define PNG_INTERNAL
@@ -1251,13 +1251,13 @@
int shift;
int d;
int value;
- png_uint_32 i, istop;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
dp = row;
d = 0;
shift = 7;
- istop = row_info->width;
- for (i = png_pass_start[pass]; i < istop;
+ for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
sp = row + (png_size_t)(i >> 3);
@@ -1285,13 +1285,13 @@
int shift;
int d;
int value;
- png_uint_32 i, istop;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
dp = row;
shift = 6;
d = 0;
- istop = row_info->width;
- for (i = png_pass_start[pass]; i < istop;
+ for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
sp = row + (png_size_t)(i >> 2);
@@ -1318,13 +1318,13 @@
int shift;
int d;
int value;
- png_uint_32 i, istop;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
dp = row;
shift = 4;
d = 0;
- istop = row_info->width;
- for (i = png_pass_start[pass]; i < istop;
+ for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
sp = row + (png_size_t)(i >> 1);
@@ -1348,7 +1348,8 @@
{
png_bytep sp;
png_bytep dp;
- png_uint_32 i, istop;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
png_size_t pixel_bytes;
/* start at the beginning */
@@ -1357,8 +1358,7 @@
pixel_bytes = (row_info->pixel_depth >> 3);
/* loop through the row, only looking at the pixels that
matter */
- istop = row_info->width;
- for (i = png_pass_start[pass]; i < istop;
+ for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
/* find out where the original pixel is */
@@ -1397,6 +1397,10 @@
png_bytep prev_row, best_row, row_buf;
png_uint_32 mins, bpp;
png_byte filter_to_do = png_ptr->do_filter;
+ png_uint_32 row_bytes = row_info->rowbytes;
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ int num_p_filters = (int)png_ptr->num_prev_filters;
+#endif
png_debug(1, "in png_write_find_filter\n");
/* find out how many bytes offset each pixel is */
@@ -1427,11 +1431,11 @@
{
png_bytep rp;
png_uint_32 sum = 0;
- png_uint_32 i,istop;
+ png_uint_32 i;
+ int j;
int v;
- istop = row_info->rowbytes;
- for (i = 0, rp = row_buf + 1; i < istop; i++, rp++)
+ for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
{
v = *rp;
sum += (v < 128) ? v : 256 - v;
@@ -1445,14 +1449,13 @@
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
/* Reduce the sum if we match any of the previous rows */
- istop = (png_uint_32)png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_NONE)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
{
- sumlo = (sumlo * png_ptr->filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1480,14 +1483,14 @@
/* it's the only filter so no testing is needed */
{
png_bytep rp, lp, dp;
- png_uint_32 i,istop;
+ png_uint_32 i;
+ int j;
for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
i++, rp++, dp++)
{
*dp = *rp;
}
- istop = row_info->rowbytes;
- for (lp = row_buf + 1; i < istop;
+ for (lp = row_buf + 1; i < row_bytes;
i++, rp++, lp++, dp++)
{
*dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
@@ -1499,7 +1502,8 @@
{
png_bytep rp, dp, lp;
png_uint_32 sum = 0, lmins = mins;
- png_uint_32 i, istop;
+ png_uint_32 i;
+ int j;
int v;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
@@ -1513,14 +1517,13 @@
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
- istop = (png_uint_32)png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_SUB)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
{
- lmlo = (lmlo * png_ptr->inv_filter_weights[i]) >>
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- lmhi = (lmhi * png_ptr->inv_filter_weights[i]) >>
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1562,14 +1565,13 @@
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
- istop = (png_uint_32)png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_SUB)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
{
- sumlo = (sumlo * png_ptr->inv_filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->inv_filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1597,11 +1599,10 @@
if (filter_to_do == PNG_FILTER_UP)
{
png_bytep rp, dp, pp;
- png_uint_32 i, istop;
+ png_uint_32 i;
- istop = row_info->rowbytes;
for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
- pp = prev_row + 1; i < istop;
+ pp = prev_row + 1; i < row_bytes;
i++, rp++, pp++, dp++)
{
*dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
@@ -1613,7 +1614,8 @@
{
png_bytep rp, dp, pp;
png_uint_32 sum = 0, lmins = mins;
- png_uint_32 i, istop;
+ png_uint_32 i;
+ int j;
int v;
@@ -1624,14 +1626,13 @@
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
- istop = (png_uint_32)png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_UP)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
{
- lmlo = (lmlo * png_ptr->inv_filter_weights[i]) >>
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- lmhi = (lmhi * png_ptr->inv_filter_weights[i]) >>
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1648,12 +1649,10 @@
}
#endif
- istop = row_info->rowbytes;
for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
- pp = prev_row + 1; i < istop;
- i++, rp++, pp++, dp++)
+ pp = prev_row + 1; i < row_bytes; i++)
{
- v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
sum += (v < 128) ? v : 256 - v;
@@ -1668,14 +1667,13 @@
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
- istop = (png_uint_32)png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_UP)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
{
- sumlo = (sumlo * png_ptr->filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1703,16 +1701,16 @@
if (filter_to_do == PNG_FILTER_AVG)
{
png_bytep rp, dp, pp, lp;
- png_uint_32 i,istop;
+ png_uint_32 i;
for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
- pp = prev_row + 1; i < bpp; i++, rp++, pp++, dp++)
+ pp = prev_row + 1; i < bpp; i++)
{
- *dp = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff);
+ *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
}
- istop = row_info->rowbytes;
- for (lp = row_buf + 1; i < istop; i++, rp++, pp++, lp++, dp++)
+ for (lp = row_buf + 1; i < row_bytes; i++)
{
- *dp = (png_byte)(((int)*rp - (((int)*pp + (int)*lp) / 2)) & 0xff);
+ *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+ & 0xff);
}
best_row = png_ptr->avg_row;
}
@@ -1721,7 +1719,8 @@
{
png_bytep rp, dp, pp, lp;
png_uint_32 sum = 0, lmins = mins;
- png_uint_32 i,istop;
+ png_uint_32 i;
+ int j;
int v;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
@@ -1731,14 +1730,13 @@
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
- istop = (png_uint_32)png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_AVG)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
{
- lmlo = (lmlo * png_ptr->inv_filter_weights[i]) >>
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- lmhi = (lmhi * png_ptr->inv_filter_weights[i]) >>
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1756,16 +1754,16 @@
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
- pp = prev_row + 1; i < bpp; i++, rp++, pp++, dp++)
+ pp = prev_row + 1; i < bpp; i++)
{
- v = *dp = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff);
+ v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
sum += (v < 128) ? v : 256 - v;
}
- istop = row_info->rowbytes;
- for (lp = row_buf + 1; i < istop; i++, rp++, pp++, lp++, dp++)
+ for (lp = row_buf + 1; i < row_bytes; i++)
{
- v = *dp = (png_byte)(((int)*rp - (((int)*pp + (int)*lp) / 2)) & 0xff);
+ v = *dp++ =
+ (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
sum += (v < 128) ? v : 256 - v;
@@ -1780,14 +1778,13 @@
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
- istop = png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_NONE)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
{
- sumlo = (sumlo * png_ptr->filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1815,38 +1812,37 @@
if (filter_to_do == PNG_FILTER_PAETH)
{
png_bytep rp, dp, pp, cp, lp;
- png_uint_32 i, istop;
+ png_uint_32 i;
for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
- pp = prev_row + 1; i < bpp; i++, rp++, pp++, dp++)
+ pp = prev_row + 1; i < bpp; i++)
{
- *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
}
- istop = row_info->rowbytes;
- for (lp = row_buf + 1, cp = prev_row + 1; i < istop;
- i++, rp++, pp++, lp++, dp++, cp++)
+ 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;
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
- p = a + b - c;
+ p = b - c;
+ pc = a - c;
#ifdef PNG_USE_ABS
- pa = abs(p - a);
- pb = abs(p - b);
- pc = abs(p - c);
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
#else
- pa = p > a ? p - a : a - p;
- pb = p > b ? p - b : b - p;
- pc = p > c ? p - c : c - p;
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
#endif
p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
- *dp = (png_byte)(((int)*rp - p) & 0xff);
+ *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
}
best_row = png_ptr->paeth_row;
}
@@ -1855,7 +1851,8 @@
{
png_bytep rp, dp, pp, cp, lp;
png_uint_32 sum = 0, lmins = mins;
- png_uint_32 i, istop;
+ png_uint_32 i;
+ int j;
int v;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
@@ -1865,14 +1862,13 @@
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
- istop = png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_PAETH)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
{
- lmlo = (lmlo * png_ptr->inv_filter_weights[i]) >>
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- lmhi = (lmhi * png_ptr->inv_filter_weights[i]) >>
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1890,38 +1886,36 @@
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
- pp = prev_row + 1; i < bpp; i++, rp++, pp++, dp++)
+ pp = prev_row + 1; i < bpp; i++)
{
- v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
sum += (v < 128) ? v : 256 - v;
}
- istop = row_info->rowbytes;
- for (lp = row_buf + 1, cp = prev_row + 1; i < istop;
- i++, rp++, pp++, lp++, dp++, cp++)
+ 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 = a + b - c;
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
#ifndef PNG_SLOW_PAETH
+ p = b - c;
+ pc = a - c;
#ifdef PNG_USE_ABS
- pa = abs(p - a);
- pb = abs(p - b);
- pc = abs(p - c);
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
#else
- pa = p > a ? p - a : a - p;
- pb = p > b ? p - b : b - p;
- pc = p > c ? p - c : c - p;
+ 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);
@@ -1933,7 +1927,7 @@
p = c;
#endif /* PNG_SLOW_PAETH */
- v = *dp = (png_byte)(((int)*rp - p) & 0xff);
+ v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
sum += (v < 128) ? v : 256 - v;
@@ -1948,14 +1942,13 @@
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
- istop = png_ptr->num_prev_filters;
- for (i = 0; i < istop; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_PAETH)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
{
- sumlo = (sumlo * png_ptr->filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
@@ -1986,14 +1979,12 @@
/* Save the type of filter we picked this time for future calculations */
if (png_ptr->num_prev_filters > 0)
{
- int i, istop;
-
- istop = (int)png_ptr->num_prev_filters;
- for (i = 1; i < istop; i++)
+ int j;
+ for (j = 1; j < num_p_filters; j++)
{
- png_ptr->prev_filters[i] = png_ptr->prev_filters[i - 1];
+ png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
}
- png_ptr->prev_filters[i] = best_row[0];
+ png_ptr->prev_filters[j] = best_row[0];
}
#endif
}