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[libpng15] Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row

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and removed a redundant assignment (Mans Rullgard).
This commit is contained in:
Mans Rullgard 2011-10-17 15:25:03 -05:00 committed by Glenn Randers-Pehrson
parent e7db181e5d
commit c9e27d026d
3 changed files with 15 additions and 15 deletions
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2
ANNOUNCE
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@ -86,6 +86,8 @@ Version 1.5.6beta06 [October 17, 2011]
of 8 bits and the image is not interlaced.
Version 1.5.6beta07 [October 17, 2011]
Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
(Mans Rullgard).
Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
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2
CHANGES
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@ -3647,6 +3647,8 @@ Version 1.5.6beta06 [October 17, 2011]
of 8 bits and the image is not interlaced.
Version 1.5.6beta07 [October 17, 2011]
Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
(Mans Rullgard).
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

26
pngrutil.c
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@ -3946,35 +3946,40 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
{
png_free(png_ptr, png_ptr->big_row_buf);
png_free(png_ptr, png_ptr->big_prev_row);
if (png_ptr->interlaced)
png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
row_bytes + 48);
else
png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr,
row_bytes + 48);
png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
png_ptr->old_big_row_buf_size = row_bytes + 48;
#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
/* Use 16-byte aligned memory for row_buf with at least 16 bytes
* of padding before and after row_buf.
* of padding before and after row_buf; treat prev_row similarly.
* NOTE: the alignment is to the start of the pixels, one beyond the start
* of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
* was incorrect, the filter byte was aligned, which had the exact opposite
* effect to that intended.
* was incorrect; the filter byte was aligned, which had the exact
* opposite effect of that intended.
*/
{
png_bytep temp = png_ptr->big_row_buf + 32;
int extra = (int)((temp - (png_bytep)0) & 0xf);
png_ptr->row_buf = temp - extra - 1/*filter byte*/;
temp = png_ptr->big_prev_row + 32;
extra = (int)((temp - (png_bytep)0) & 0xf);
png_ptr->prev_row = temp - extra - 1/*filter byte*/;
}
png_ptr->old_big_row_buf_size = row_bytes + 48;
#else
/* Use 31 bytes of padding before and 17 bytes after row_buf. */
png_ptr->row_buf = png_ptr->big_row_buf + 31;
png_ptr->prev_row = png_ptr->big_prev_row + 31;
#endif
png_ptr->old_big_row_buf_size = row_bytes + 48;
}
@ -3987,15 +3992,6 @@ defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
png_error(png_ptr, "Row has too many bytes to allocate in memory");
if (png_ptr->rowbytes + 1 > png_ptr->old_prev_row_size)
{
png_free(png_ptr, png_ptr->prev_row);
png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);
png_ptr->old_prev_row_size = png_ptr->rowbytes + 1;
}
png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
png_debug1(3, "width = %u,", png_ptr->width);