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#include <u.h>
#include <libc.h>
#include <draw.h>
Image*
readimage(Display *d, int fd, int dolock)
{
char hdr[5*12+1];
int dy;
int new;
uint l, n;
int m, j, chunk;
int miny, maxy;
Rectangle r;
int ldepth;
u32int chan;
uchar *tmp;
Image *i;
if(readn(fd, hdr, 11) != 11)
return nil;
if(memcmp(hdr, "compressed\n", 11) == 0)
return creadimage(d, fd, dolock);
if(readn(fd, hdr+11, 5*12-11) != 5*12-11)
return nil;
if(d)
chunk = d->bufsize - 32; /* a little room for header */
else
chunk = 8192;
/*
* distinguish new channel descriptor from old ldepth.
* channel descriptors have letters as well as numbers,
* while ldepths are a single digit formatted as %-11d.
*/
new = 0;
for(m=0; m<10; m++){
if(hdr[m] != ' '){
new = 1;
break;
}
}
if(hdr[11] != ' '){
werrstr("readimage: bad format");
return nil;
}
if(new){
hdr[11] = '\0';
if((chan = strtochan(hdr)) == 0){
werrstr("readimage: bad channel string %s", hdr);
return nil;
}
}else{
ldepth = ((int)hdr[10])-'0';
if(ldepth<0 || ldepth>3){
werrstr("readimage: bad ldepth %d", ldepth);
return nil;
}
chan = drawld2chan[ldepth];
}
r.min.x = atoi(hdr+1*12);
r.min.y = atoi(hdr+2*12);
r.max.x = atoi(hdr+3*12);
r.max.y = atoi(hdr+4*12);
if(r.min.x>r.max.x || r.min.y>r.max.y){
werrstr("readimage: bad rectangle");
return nil;
}
miny = r.min.y;
maxy = r.max.y;
l = bytesperline(r, chantodepth(chan));
if(d){
if(dolock)
lockdisplay(d);
i = allocimage(d, r, chan, 0, -1);
if(dolock)
unlockdisplay(d);
if(i == nil)
return nil;
}else{
i = mallocz(sizeof(Image), 1);
if(i == nil)
return nil;
}
tmp = malloc(chunk);
if(tmp == nil)
goto Err;
while(maxy > miny){
dy = maxy - miny;
if(dy*l > chunk)
dy = chunk/l;
if(dy <= 0){
werrstr("readimage: image too wide for buffer");
goto Err;
}
n = dy*l;
m = readn(fd, tmp, n);
if(m != n){
werrstr("readimage: read count %d not %d: %r", m, n);
Err:
if(dolock)
lockdisplay(d);
Err1:
freeimage(i);
if(dolock)
unlockdisplay(d);
free(tmp);
return nil;
}
if(!new) /* an old image: must flip all the bits */
for(j=0; j<chunk; j++)
tmp[j] ^= 0xFF;
if(d){
if(dolock)
lockdisplay(d);
if(loadimage(i, Rect(r.min.x, miny, r.max.x, miny+dy), tmp, chunk) <= 0)
goto Err1;
if(dolock)
unlockdisplay(d);
}
miny += dy;
}
free(tmp);
return i;
}
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