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[libpng17] #ifdef out some dead code in pngrtran.c when sBIT is disabled.

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This commit is contained in:
Glenn Randers-Pehrson 2015-09-25 22:33:41 -05:00
parent 7441965463
commit c23bdb1445
1 changed files with 14 additions and 5 deletions
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19
pngrtran.c
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@ -867,10 +867,12 @@ png_do_expand_lbd_gray(png_transformp *transform, png_transform_controlp tc)
const png_const_bytep ep = dp; const png_const_bytep ep = dp;
png_const_bytep sp = png_voidcast(png_const_bytep, tc->sp); png_const_bytep sp = png_voidcast(png_const_bytep, tc->sp);
const unsigned int bit_depth = tc->bit_depth; const unsigned int bit_depth = tc->bit_depth;
# ifdef PNG_READ_sBIT_SUPPORTED
unsigned int insignificant_bits = 0U; unsigned int insignificant_bits = 0U;
# endif /* READ_sBIT */
# ifdef PNG_READ_tRNS_SUPPORTED # ifdef PNG_READ_tRNS_SUPPORTED
unsigned int gray = 0xffffU; /* doesn't match anything */ unsigned int gray = 0xffffU; /* doesn't match anything */
unsigned int do_alpha = 0U; unsigned int do_alpha = 0U;
# endif /* READ_tRNS */ # endif /* READ_tRNS */
sp += PNG_TC_ROWBYTES(*tc); /* last byte +1 */ sp += PNG_TC_ROWBYTES(*tc); /* last byte +1 */
@ -941,6 +943,7 @@ png_do_expand_lbd_gray(png_transformp *transform, png_transform_controlp tc)
check_tRNS check_tRNS
# ifdef PNG_READ_sBIT_SUPPORTED
/* 'sig_bits' must be 1 or 2 leaving insignificant_bits 0 or /* 'sig_bits' must be 1 or 2 leaving insignificant_bits 0 or
* 1. This may look silly but it allows a compact representation * 1. This may look silly but it allows a compact representation
* of 1 bit gray + 1 bit alpha (transparency): * of 1 bit gray + 1 bit alpha (transparency):
@ -952,6 +955,7 @@ png_do_expand_lbd_gray(png_transformp *transform, png_transform_controlp tc)
} }
else else
# endif
*--dp = PNG_BYTE(pixel * 85U); *--dp = PNG_BYTE(pixel * 85U);
if (dp <= ep) break; if (dp <= ep) break;
@ -967,7 +971,9 @@ png_do_expand_lbd_gray(png_transformp *transform, png_transform_controlp tc)
{ {
unsigned int shift = 7U & -(tc->width << 2)/*overflow ok*/; unsigned int shift = 7U & -(tc->width << 2)/*overflow ok*/;
unsigned int s = *--sp; unsigned int s = *--sp;
# ifdef PNG_READ_sBIT_SUPPORTED
const unsigned int div = (1U << (4U-insignificant_bits)) - 1U; const unsigned int div = (1U << (4U-insignificant_bits)) - 1U;
# endif
for (;;) for (;;)
{ {
@ -977,9 +983,11 @@ png_do_expand_lbd_gray(png_transformp *transform, png_transform_controlp tc)
check_tRNS check_tRNS
/* insignifcant_bits may be 0, 1, 2 or 3, requiring a multiply by # ifdef PNG_READ_sBIT_SUPPORTED
* 17, 255/7, 85 or 255. Since this operation is always cached /* insignificant_bits may be 0, 1, 2 or 3, requiring a multiply
* we don't much care about the time to do the divide below. * by 17, 255/7, 85 or 255. Since this operation is always
* cached we don't much care about the time to do the divide
* below.
*/ */
if (insignificant_bits) if (insignificant_bits)
{ {
@ -988,6 +996,7 @@ png_do_expand_lbd_gray(png_transformp *transform, png_transform_controlp tc)
} }
else else
# endif
pixel *= 17U; pixel *= 17U;
*--dp = PNG_BYTE(pixel); *--dp = PNG_BYTE(pixel);