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(mpng_decode) Cleanups

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This commit is contained in:
twinaphex 2015-02-17 03:49:39 +01:00
parent 5db053b506
commit aee6610960
1 changed files with 32 additions and 25 deletions
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57
libretro-sdk/formats/mpng/mpng_decode.c
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@ -139,17 +139,22 @@ bool png_decode(const void *userdata, size_t len,
* Greyscale with alpha 4
* Truecolour with alpha 6
**/
/* Truecolor; can be 16bpp but I don't want that. */
if (color_type == 2 && depth != 8)
goto error; /* truecolor; can be 16bpp but I don't want that. */
goto error;
/* Paletted. */
if (color_type == 3 && depth != 1 && depth != 2 && depth != 4 && depth != 8)
goto error; /* paletted */
goto error;
/* Truecolor with alpha. */
if (color_type == 6 && depth != 8)
goto error; /* truecolor with alpha */
goto error;
/* Can only decode alpha on ARGB formats. */
if (color_type == 6 && format != FMT_ARGB8888)
goto error; /* can only decode alpha on ARGB formats */
goto error;
if (compression != 0)
goto error;
@ -184,7 +189,7 @@ bool png_decode(const void *userdata, size_t len,
if (chunklen == 0 || chunklen % 3 || chunklen > 3 * 256)
goto error;
/* palette on RGB is allowed but rare,
/* Palette on RGB is allowed but rare,
* and it's just a recommendation anyways. */
if (color_type != 3)
break;
@ -255,6 +260,8 @@ bool png_decode(const void *userdata, size_t len,
tinfl_status status;
#endif
size_t finalbytes;
unsigned int bpp_packed;
uint8_t *prevout;
size_t zero = 0;
uint8_t * out = NULL;
uint8_t * filteredline = NULL;
@ -280,23 +287,23 @@ bool png_decode(const void *userdata, size_t len,
if (status > TINFL_STATUS_DONE)
goto error;
#endif
/* Too little data (can't be too much
* because we didn't give it that buffer size) */
if (pixelsat != pixelsend)
goto error; /* too little data (can't be too much because we didn't give it that buffer size) */
goto error;
out = (uint8_t*)malloc(videofmt_byte_per_pixel(format) * width * height);
//TODO: deinterlace at random point
/* TODO: deinterlace at random point */
//run filters
unsigned int bpppacked = ((color_type == 2) ? 3 : (color_type == 6) ? 4 : 1);
uint8_t * prevout = out + (4 * width * 1);
/* run filters */
bpp_packed = ((color_type == 2) ? 3 : (color_type == 6) ? 4 : 1);
prevout = (out + (4 * width * 1));
/* This will blow up if a 1px high image
* is filtered with Paeth, but highly unlikely. */
if (height==1)
{
/* This will blow up if a 1px high image is filtered with Paeth, but highly unlikely. */
prevout=out;
}
/* Not using bpp here because we only need a chunk of black anyways */
memset(prevout, 0, 4 * width * 1);
@ -305,7 +312,7 @@ bool png_decode(const void *userdata, size_t len,
for (y = 0; y < height; y++)
{
uint8_t * thisout=out+(bpl*y);
uint8_t *thisout = (uint8_t*)(out + (bpl*y));
switch (*(filteredline++))
{
@ -313,31 +320,31 @@ bool png_decode(const void *userdata, size_t len,
memcpy(thisout, filteredline, bpl);
break;
case 1:
memcpy(thisout, filteredline, bpppacked);
memcpy(thisout, filteredline, bpp_packed);
for (x = bpppacked; x < bpl; x++)
thisout[x] = thisout[x-bpppacked] + filteredline[x];
for (x = bpp_packed; x < bpl; x++)
thisout[x] = thisout[x - bpp_packed] + filteredline[x];
break;
case 2:
for (x = 0; x < bpl; x++)
thisout[x] = prevout[x] + filteredline[x];
break;
case 3:
for (x = 0; x < bpppacked; x++)
for (x = 0; x < bpp_packed; x++)
{
int a = 0;
int b = prevout[x];
thisout[x] = (a+b)/2 + filteredline[x];
}
for (x = bpppacked; x < bpl; x++)
for (x = bpp_packed; x < bpl; x++)
{
int a = thisout[x - bpppacked];
int a = thisout[x - bpp_packed];
int b = prevout[x];
thisout[x] = (a + b) / 2 + filteredline[x];
}
break;
case 4:
for (x = 0; x < bpppacked; x++)
for (x = 0; x < bpp_packed; x++)
{
int prediction;
@ -360,13 +367,13 @@ bool png_decode(const void *userdata, size_t len,
thisout[x] = filteredline[x]+prediction;
}
for (x = bpppacked; x < bpl; x++)
for (x = bpp_packed; x < bpl; x++)
{
int prediction;
int a = thisout[x-bpppacked];
int a = thisout[x - bpp_packed];
int b = prevout[x];
int c = prevout[x-bpppacked];
int c = prevout[x - bpp_packed];
int p = a+b-c;
int pa = abs(p-a);