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[libpng16] Fixed build warnings (MSVC, GCC, GCC v3). Cygwin GCC with default

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options declares 'index' as a global, causing a warning if it is used as a
local variable.  GCC 64-bit warns about assigning a (size_t) (unsigned 64-bit)
to an (int) (signed 32-bit).  MSVC, however, warns about using the
unary '-' operator on an unsigned value (even though it is well defined
by ANSI-C to be ~x+1).  The padding calculation was changed to use a
different method.  Removed the tests on png_ptr->pass.
This commit is contained in:
John Bowler
2012-03-03 20:49:03 -06:00
committed by Glenn Randers-Pehrson
parent 434801a39c
commit 29a6ba01a7
3 changed files with 47 additions and 31 deletions
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58
pngtrans.c
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@@ -625,11 +625,16 @@ png_do_bgr(png_row_infop row_info, png_bytep row)
void /* PRIVATE */
png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
{
if (png_ptr->num_palette < (1 << row_info->bit_depth) &&
png_ptr->num_palette_max >= 0 &&
((png_ptr->interlaced && png_ptr->pass == 6) ||
(!png_ptr->interlaced && png_ptr->pass == 0)))
if (png_ptr->num_palette < (1 << row_info->bit_depth) &&
png_ptr->num_palette_max >= 0)
{
/* Calculations moved outside switch in an attempt to stop different
* compiler warnings. 'padding' is in *bits* within the last byte, it is
* an 'int' because pixel_depth becomes an 'int' in the expression below,
* and this calculation is used because it avoids warnings that other
* forms produced on either GCC or MSVC.
*/
int padding = (-row_info->pixel_depth * row_info->width) & 7;
png_bytep rp = png_ptr->row_buf + 1 + row_info->rowbytes;
switch (row_info->bit_depth)
@@ -639,8 +644,6 @@ png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
/* in this case, all bytes must be 0 so we don't need
* to unpack the pixels except for the rightmost one.
*/
int padding = 8*row_info->rowbytes - png_ptr->width;
for (; rp > png_ptr->row_buf; rp--)
{
if (*rp >> padding != 0)
@@ -653,29 +656,27 @@ png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
case 2:
{
int padding = 2*(4*row_info->rowbytes - png_ptr->width);
for (; rp > png_ptr->row_buf; rp--)
{
int index = ((*rp >> padding) & 0x03);
int i = ((*rp >> padding) & 0x03);
if (index > png_ptr->num_palette_max)
png_ptr->num_palette_max = index;
if (i > png_ptr->num_palette_max)
png_ptr->num_palette_max = i;
index = (((*rp >> padding) >> 2) & 0x03);
i = (((*rp >> padding) >> 2) & 0x03);
if (index > png_ptr->num_palette_max)
png_ptr->num_palette_max = index;
if (i > png_ptr->num_palette_max)
png_ptr->num_palette_max = i;
index = (((*rp >> padding) >> 4) & 0x03);
i = (((*rp >> padding) >> 4) & 0x03);
if (index > png_ptr->num_palette_max)
png_ptr->num_palette_max = index;
if (i > png_ptr->num_palette_max)
png_ptr->num_palette_max = i;
index = (((*rp >> padding) >> 6) & 0x03);
i = (((*rp >> padding) >> 6) & 0x03);
if (index > png_ptr->num_palette_max)
png_ptr->num_palette_max = index;
if (i > png_ptr->num_palette_max)
png_ptr->num_palette_max = i;
padding = 0;
}
@@ -685,19 +686,17 @@ png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
case 4:
{
int padding = 4*(2*row_info->rowbytes - png_ptr->width);
for (; rp > png_ptr->row_buf; rp--)
{
int index = ((*rp >> padding) & 0x0f);
int i = ((*rp >> padding) & 0x0f);
if (index > png_ptr->num_palette_max)
png_ptr->num_palette_max = index;
if (i > png_ptr->num_palette_max)
png_ptr->num_palette_max = i;
index = (((*rp >> padding) >> 4) & 0x0f);
i = (((*rp >> padding) >> 4) & 0x0f);
if (index > png_ptr->num_palette_max)
png_ptr->num_palette_max = index;
if (i > png_ptr->num_palette_max)
png_ptr->num_palette_max = i;
padding = 0;
}
@@ -715,6 +714,9 @@ png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
break;
}
default:
break;
}
}
}