/*
* The Python Imaging Library.
* $Id: MspDecode.c 2134 2004-10-06 08:55:20Z fredrik $
*
* decoder for MSP version 2 data.
*
* history:
* 97-01-03 fl Created
*
* Copyright (c) Fredrik Lundh 1997.
* Copyright (c) Secret Labs AB 1997.
*
* See the README file for information on usage and redistribution.
*/
#include "Imaging.h"
int
ImagingMspDecode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
{
int n;
UINT8* ptr;
ptr = buf;
for (;;) {
if (bytes < 1)
return ptr - buf;
if (ptr[0] == 0) {
/* Run (3 bytes block) */
if (bytes < 3)
break;
n = ptr[1];
if (state->x + n > state->bytes) {
state->errcode = IMAGING_CODEC_OVERRUN;
return -1;
}
memset(state->buffer + state->x, ptr[2], n);
ptr += 3;
bytes -= 3;
} else {
/* Literal (1+n bytes block) */
n = ptr[0];
if (bytes < 1 + n)
break;
if (state->x + n > state->bytes) {
state->errcode = IMAGING_CODEC_OVERRUN;
return -1;
}
memcpy(state->buffer + state->x, ptr + 1, n);
ptr += 1 + n;
bytes -= 1 + n;
}
state->x += n;
if (state->x >= state->bytes) {
/* 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;
}
}
}
return ptr - buf;
}
