Pillow/libImaging/PcxDecode.c
2015-10-11 21:24:35 +11:00

85 lines
1.6 KiB
C

/*
* The Python Imaging Library.
* $Id$
*
* decoder for PCX image data.
*
* history:
* 95-09-14 fl Created
*
* Copyright (c) Fredrik Lundh 1995.
* Copyright (c) Secret Labs AB 1997.
*
* See the README file for information on usage and redistribution.
*/
#include "Imaging.h"
int
ImagingPcxDecode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
{
UINT8 n;
UINT8* ptr;
ptr = buf;
for (;;) {
if (bytes < 1)
return ptr - buf;
if ((*ptr & 0xC0) == 0xC0) {
/* Run */
if (bytes < 2)
return ptr - buf;
n = ptr[0] & 0x3F;
while (n > 0) {
if (state->x >= state->bytes) {
state->errcode = IMAGING_CODEC_OVERRUN;
break;
}
state->buffer[state->x++] = ptr[1];
n--;
}
ptr += 2; bytes -= 2;
} else {
/* Literal */
state->buffer[state->x++] = ptr[0];
ptr++; bytes--;
}
if (state->x >= state->bytes) {
if (state->bytes % state->xsize && state->bytes > state->xsize) {
int bands = state->bytes / state->xsize;
int stride = state->bytes / bands;
int i;
for (i=1; i< bands; i++) { // note -- skipping first band
memmove(&state->buffer[i*state->xsize],
&state->buffer[i*stride],
state->xsize);
}
}
/* Got a full line, unpack it */
state->shuffle((UINT8*) im->image[state->y + state->yoff] +
state->xoff * im->pixelsize, state->buffer,
state->xsize);
state->x = 0;
if (++state->y >= state->ysize) {
/* End of file (errcode = 0) */
return -1;
}
}
}
}