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optimized palette decoding

This commit is contained in:
Andre Leiradella 2016-05-29 10:57:57 -03:00
parent d9ea20727c
commit 516918c163
1 changed files with 93 additions and 11 deletions
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104
libretro-common/formats/png/rpng.c
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@ -327,18 +327,100 @@ static void png_reverse_filter_copy_line_plt(uint32_t *data,
const uint8_t *decoded, unsigned width, const uint8_t *decoded, unsigned width,
unsigned depth, const uint32_t *palette) unsigned depth, const uint32_t *palette)
{ {
unsigned i, bit; switch (depth)
unsigned mask = (1 << depth) - 1;
bit = 0;
for (i = 0; i < width; i++, bit += depth)
{ {
unsigned byte = bit >> 3; case 1:
unsigned val = decoded[byte] >> (8 - depth - (bit & 7)); {
unsigned w = width / 8;
val &= mask; unsigned i;
data[i] = palette[val];
for (i = 0; i < w; i++, decoded++)
{
*data++ = palette[(*decoded >> 7) & 1];
*data++ = palette[(*decoded >> 6) & 1];
*data++ = palette[(*decoded >> 5) & 1];
*data++ = palette[(*decoded >> 4) & 1];
*data++ = palette[(*decoded >> 3) & 1];
*data++ = palette[(*decoded >> 2) & 1];
*data++ = palette[(*decoded >> 1) & 1];
*data++ = palette[*decoded & 1];
}
switch (width & 7)
{
case 7:
data[6] = palette[(*decoded >> 1) & 1];
case 6:
data[5] = palette[(*decoded >> 2) & 1];
case 5:
data[4] = palette[(*decoded >> 3) & 1];
case 4:
data[3] = palette[(*decoded >> 4) & 1];
case 3:
data[2] = palette[(*decoded >> 5) & 1];
case 2:
data[1] = palette[(*decoded >> 6) & 1];
case 1:
data[0] = palette[(*decoded >> 7) & 1];
break;
}
}
break;
case 2:
{
unsigned w = width / 4;
unsigned i;
for (i = 0; i < w; i++, decoded++)
{
*data++ = palette[(*decoded >> 6) & 3];
*data++ = palette[(*decoded >> 4) & 3];
*data++ = palette[(*decoded >> 2) & 3];
*data++ = palette[*decoded & 3];
}
switch (width & 3)
{
case 3:
data[2] = palette[(*decoded >> 2) & 3];
case 2:
data[1] = palette[(*decoded >> 4) & 3];
case 1:
data[0] = palette[(*decoded >> 6) & 3];
break;
}
}
break;
case 4:
{
unsigned w = width / 2;
unsigned i;
for (i = 0; i < w; i++, decoded++)
{
*data++ = palette[*decoded >> 4];
*data++ = palette[*decoded & 0x0f];
}
if (width & 1)
{
*data = palette[*decoded >> 4];
}
}
break;
case 8:
{
unsigned i;
for (i = 0; i < width; i++, decoded++, data++)
{
*data = palette[*decoded];
}
}
break;
} }
} }