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#include <u.h>
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#include <libc.h>
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#include <draw.h>
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Image*
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readimage(Display *d, int fd, int dolock)
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{
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	char hdr[5*12+1];
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	int dy;
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	int new;
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	uint l, n;
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	int m, j, chunk;
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	int miny, maxy;
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	Rectangle r;
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	int ldepth;
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	ulong chan;
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	uchar *tmp;
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	Image *i;
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	if(readn(fd, hdr, 11) != 11)
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		return nil;
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	if(memcmp(hdr, "compressed\n", 11) == 0)
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		return creadimage(d, fd, dolock);
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	if(readn(fd, hdr+11, 5*12-11) != 5*12-11)
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		return nil;
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	if(d)
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		chunk = d->bufsize - 32;	/* a little room for header */
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	else
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		chunk = 8192;
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	/*
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	 * distinguish new channel descriptor from old ldepth.
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	 * channel descriptors have letters as well as numbers,
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	 * while ldepths are a single digit formatted as %-11d.
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	 */
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	new = 0;
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	for(m=0; m<10; m++){
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		if(hdr[m] != ' '){
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			new = 1;
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			break;
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		}
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	}
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	if(hdr[11] != ' '){
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		werrstr("readimage: bad format");
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		return nil;
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	}
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	if(new){
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		hdr[11] = '\0';
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		if((chan = strtochan(hdr)) == 0){
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			werrstr("readimage: bad channel string %s", hdr);
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			return nil;
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		}
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	}else{
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		ldepth = ((int)hdr[10])-'0';
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		if(ldepth<0 || ldepth>3){
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			werrstr("readimage: bad ldepth %d", ldepth);
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			return nil;
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		}
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		chan = drawld2chan[ldepth];
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	}
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	r.min.x = atoi(hdr+1*12);
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	r.min.y = atoi(hdr+2*12);
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	r.max.x = atoi(hdr+3*12);
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	r.max.y = atoi(hdr+4*12);
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	if(r.min.x>r.max.x || r.min.y>r.max.y){
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		werrstr("readimage: bad rectangle");
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		return nil;
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	}
70 
 
71 
	miny = r.min.y;
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	maxy = r.max.y;
73 
 
74 
	l = bytesperline(r, chantodepth(chan));
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	if(d){
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		if(dolock)
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			lockdisplay(d);
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		i = allocimage(d, r, chan, 0, -1);
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		if(dolock)
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			unlockdisplay(d);
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		if(i == nil)
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			return nil;
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	}else{
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		i = mallocz(sizeof(Image), 1);
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		if(i == nil)
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			return nil;
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	}
88 
 
89 
	tmp = malloc(chunk);
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	if(tmp == nil)
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		goto Err;
92 
	while(maxy > miny){
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		dy = maxy - miny;
94 
		if(dy*l > chunk)
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			dy = chunk/l;
96 
		if(dy <= 0){
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			werrstr("readimage: image too wide for buffer");
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			goto Err;
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		}
100 
		n = dy*l;
101 
		m = readn(fd, tmp, n);
102 
		if(m != n){
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			werrstr("readimage: read count %d not %d: %r", m, n);
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   Err:
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			if(dolock)
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				lockdisplay(d);
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   Err1:
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 			freeimage(i);
109 
			if(dolock)
110 
				unlockdisplay(d);
111 
			free(tmp);
112 
			return nil;
113 
		}
114 
		if(!new)	/* an old image: must flip all the bits */
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			for(j=0; j<chunk; j++)
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				tmp[j] ^= 0xFF;
117 
 
118 
		if(d){
119 
			if(dolock)
120 
				lockdisplay(d);
121 
			if(loadimage(i, Rect(r.min.x, miny, r.max.x, miny+dy), tmp, chunk) <= 0)
122 
				goto Err1;
123 
			if(dolock)
124 
				unlockdisplay(d);
125 
		}
126 
		miny += dy;
127 
	}
128 
	free(tmp);
129 
	return i;
130 
}