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/*
* The Python Imaging Library.
* $Id$
*
* decoder for Sgi RLE data.
*
* history:
* 2017-07-28 mb fixed for images larger than 64KB
* 2017-07-20 mb created
*
* Copyright (c) Mickael Bonfill 2017.
*
* See the README file for information on usage and redistribution.
*/
#include "Imaging.h"
#include "Sgi.h"
#define SGI_HEADER_SIZE 512
#define RLE_COPY_FLAG 0x80
#define RLE_MAX_RUN 0x7f
static void read4B(UINT32* dest, UINT8* buf)
{
*dest = (UINT32)((buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]);
}
static int expandrow(UINT8* dest, UINT8* src, int n, int z, int xsize)
{
UINT8 pixel, count;
for (;n > 0; n--)
{
pixel = *src++;
if (n == 1 && pixel != 0)
return n;
count = pixel & RLE_MAX_RUN;
if (!count)
return count;
if (count > xsize) {
return -1;
}
if (pixel & RLE_COPY_FLAG) {
while(count--) {
*dest = *src++;
dest += z;
}
}
else {
pixel = *src++;
while (count--) {
*dest = pixel;
dest += z;
}
}
}
return 0;
}
static int expandrow2(UINT8* dest, const UINT8* src, int n, int z, int xsize)
{
UINT8 pixel, count;
for (;n > 0; n--)
{
pixel = src[1];
src+=2;
if (n == 1 && pixel != 0)
return n;
count = pixel & RLE_MAX_RUN;
if (!count)
return count;
if (count > xsize) {
return -1;
}
if (pixel & RLE_COPY_FLAG) {
while(count--) {
memcpy(dest, src, 2);
src += 2;
dest += z * 2;
}
}
else {
while (count--) {
memcpy(dest, src, 2);
dest += z * 2;
}
src+=2;
}
}
return 0;
}
int
ImagingSgiRleDecode(Imaging im, ImagingCodecState state,
UINT8* buf, Py_ssize_t bytes)
{
UINT8 *ptr;
SGISTATE *c;
int err = 0;
int status;
/* Get all data from File descriptor */
c = (SGISTATE*)state->context;
_imaging_seek_pyFd(state->fd, 0L, SEEK_END);
c->bufsize = _imaging_tell_pyFd(state->fd);
c->bufsize -= SGI_HEADER_SIZE;
ptr = malloc(sizeof(UINT8) * c->bufsize);
if (!ptr) {
return IMAGING_CODEC_MEMORY;
}
_imaging_seek_pyFd(state->fd, SGI_HEADER_SIZE, SEEK_SET);
_imaging_read_pyFd(state->fd, (char*)ptr, c->bufsize);
/* decoder initialization */
state->count = 0;
state->y = 0;
if (state->ystep < 0) {
state->y = im->ysize - 1;
} else {
state->ystep = 1;
}
if (im->xsize > INT_MAX / im->bands ||
im->ysize > INT_MAX / im->bands) {
err = IMAGING_CODEC_MEMORY;
goto sgi_finish_decode;
}
/* Allocate memory for RLE tables and rows */
free(state->buffer);
state->buffer = NULL;
/* malloc overflow check above */
state->buffer = calloc(im->xsize * im->bands, sizeof(UINT8) * 2);
c->tablen = im->bands * im->ysize;
c->starttab = calloc(c->tablen, sizeof(UINT32));
c->lengthtab = calloc(c->tablen, sizeof(UINT32));
if (!state->buffer ||
!c->starttab ||
!c->lengthtab) {
err = IMAGING_CODEC_MEMORY;
goto sgi_finish_decode;
}
/* populate offsets table */
for (c->tabindex = 0, c->bufindex = 0; c->tabindex < c->tablen; c->tabindex++, c->bufindex+=4)
read4B(&c->starttab[c->tabindex], &ptr[c->bufindex]);
/* populate lengths table */
for (c->tabindex = 0, c->bufindex = c->tablen * sizeof(UINT32); c->tabindex < c->tablen; c->tabindex++, c->bufindex+=4)
read4B(&c->lengthtab[c->tabindex], &ptr[c->bufindex]);
state->count += c->tablen * sizeof(UINT32) * 2;
/* read compressed rows */
for (c->rowno = 0; c->rowno < im->ysize; c->rowno++, state->y += state->ystep)
{
for (c->channo = 0; c->channo < im->bands; c->channo++)
{
c->rleoffset = c->starttab[c->rowno + c->channo * im->ysize];
c->rlelength = c->lengthtab[c->rowno + c->channo * im->ysize];
c->rleoffset -= SGI_HEADER_SIZE;
if (c->rleoffset + c->rlelength > c->bufsize) {
state->errcode = IMAGING_CODEC_OVERRUN;
return -1;
}
/* row decompression */
if (c->bpc ==1) {
status = expandrow(&state->buffer[c->channo], &ptr[c->rleoffset], c->rlelength, im->bands, im->xsize);
}
else {
status = expandrow2(&state->buffer[c->channo * 2], &ptr[c->rleoffset], c->rlelength, im->bands, im->xsize);
}
if (status == -1) {
state->errcode = IMAGING_CODEC_OVERRUN;
return -1;
} else if (status == 1) {
goto sgi_finish_decode;
}
state->count += c->rlelength;
}
/* store decompressed data in image */
state->shuffle((UINT8*)im->image[state->y], state->buffer, im->xsize);
}
c->bufsize++;
sgi_finish_decode: ;
free(c->starttab);
free(c->lengthtab);
free(ptr);
if (err != 0){
return err;
}
return state->count - c->bufsize;
}
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