1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 
5 Image*
6 readimage(Display *d, int fd, int dolock)
7 {
8 	char hdr[5*12+1];
9 	int dy;
10 	int new;
11 	uint l, n;
12 	int m, j, chunk;
13 	int miny, maxy;
14 	Rectangle r;
15 	int ldepth;
16 	u32int chan;
17 	uchar *tmp;
18 	Image *i;
19 
20 	if(readn(fd, hdr, 11) != 11)
21 		return nil;
22 	if(memcmp(hdr, "compressed\n", 11) == 0)
23 		return creadimage(d, fd, dolock);
24 	if(readn(fd, hdr+11, 5*12-11) != 5*12-11)
25 		return nil;
26 	chunk = d->bufsize - 32;	/* a little room for header */
27 
28 	/*
29 	 * distinguish new channel descriptor from old ldepth.
30 	 * channel descriptors have letters as well as numbers,
31 	 * while ldepths are a single digit formatted as %-11d.
32 	 */
33 	new = 0;
34 	for(m=0; m<10; m++){
35 		if(hdr[m] != ' '){
36 			new = 1;
37 			break;
38 		}
39 	}
40 	if(hdr[11] != ' '){
41 		werrstr("readimage: bad format");
42 		return nil;
43 	}
44 	if(new){
45 		hdr[11] = '\0';
46 		if((chan = strtochan(hdr)) == 0){
47 			werrstr("readimage: bad channel string %s", hdr);
48 			return nil;
49 		}
50 	}else{
51 		ldepth = ((int)hdr[10])-'0';
52 		if(ldepth<0 || ldepth>3){
53 			werrstr("readimage: bad ldepth %d", ldepth);
54 			return nil;
55 		}
56 		chan = drawld2chan[ldepth];
57 	}
58 
59 	r.min.x = atoi(hdr+1*12);
60 	r.min.y = atoi(hdr+2*12);
61 	r.max.x = atoi(hdr+3*12);
62 	r.max.y = atoi(hdr+4*12);
63 	if(r.min.x>r.max.x || r.min.y>r.max.y){
64 		werrstr("readimage: bad rectangle");
65 		return nil;
66 	}
67 
68 	miny = r.min.y;
69 	maxy = r.max.y;
70 
71 	l = bytesperline(r, chantodepth(chan));
72 	if(dolock)
73 		lockdisplay(d);
74 	i = allocimage(d, r, chan, 0, -1);
75 	if(dolock)
76 		unlockdisplay(d);
77 	if(i == nil)
78 		return nil;
79 	tmp = malloc(chunk);
80 	if(tmp == nil)
81 		goto Err;
82 	while(maxy > miny){
83 		dy = maxy - miny;
84 		if(dy*l > chunk)
85 			dy = chunk/l;
86 		if(dy <= 0){
87 			werrstr("readimage: image too wide for buffer");
88 			goto Err;
89 		}
90 		n = dy*l;
91 		m = readn(fd, tmp, n);
92 		if(m != n){
93 			werrstr("readimage: read count %d not %d: %r", m, n);
94    Err:
95 			if(dolock)
96 				lockdisplay(d);
97    Err1:
98  			freeimage(i);
99 			if(dolock)
100 				unlockdisplay(d);
101 			free(tmp);
102 			return nil;
103 		}
104 		if(!new)	/* an old image: must flip all the bits */
105 			for(j=0; j<chunk; j++)
106 				tmp[j] ^= 0xFF;
107 
108 		if(dolock)
109 			lockdisplay(d);
110 		if(loadimage(i, Rect(r.min.x, miny, r.max.x, miny+dy), tmp, chunk) <= 0)
111 			goto Err1;
112 		if(dolock)
113 			unlockdisplay(d);
114 		miny += dy;
115 	}
116 	free(tmp);
117 	return i;
118 }