1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 #include <memdraw.h>
5 
6 Memimage*
7 creadmemimage(int fd)
8 {
9 	char hdr[5*12+1];
10 	Rectangle r;
11 	int m, nb, miny, maxy, new, ldepth, ncblock;
12 	uchar *buf;
13 	Memimage *i;
14 	u32int chan;
15 
16 	if(readn(fd, hdr, 5*12) != 5*12){
17 		werrstr("readmemimage: short header (2)");
18 		return nil;
19 	}
20 
21 	/*
22 	 * distinguish new channel descriptor from old ldepth.
23 	 * channel descriptors have letters as well as numbers,
24 	 * while ldepths are a single digit formatted as %-11d.
25 	 */
26 	new = 0;
27 	for(m=0; m<10; m++){
28 		if(hdr[m] != ' '){
29 			new = 1;
30 			break;
31 		}
32 	}
33 	if(hdr[11] != ' '){
34 		werrstr("creadimage: bad format");
35 		return nil;
36 	}
37 	if(new){
38 		hdr[11] = '\0';
39 		if((chan = strtochan(hdr)) == 0){
40 			werrstr("creadimage: bad channel string %s", hdr);
41 			return nil;
42 		}
43 	}else{
44 		ldepth = ((int)hdr[10])-'0';
45 		if(ldepth<0 || ldepth>3){
46 			werrstr("creadimage: bad ldepth %d", ldepth);
47 			return nil;
48 		}
49 		chan = drawld2chan[ldepth];
50 	}
51 	r.min.x=atoi(hdr+1*12);
52 	r.min.y=atoi(hdr+2*12);
53 	r.max.x=atoi(hdr+3*12);
54 	r.max.y=atoi(hdr+4*12);
55 	if(r.min.x>r.max.x || r.min.y>r.max.y){
56 		werrstr("creadimage: bad rectangle");
57 		return nil;
58 	}
59 
60 	i = allocmemimage(r, chan);
61 	if(i == nil)
62 		return nil;
63 	ncblock = _compblocksize(r, i->depth);
64 	buf = malloc(ncblock);
65 	if(buf == nil)
66 		goto Errout;
67 	miny = r.min.y;
68 	while(miny != r.max.y){
69 		if(readn(fd, hdr, 2*12) != 2*12){
70 		Shortread:
71 			werrstr("readmemimage: short read");
72 		Errout:
73 			freememimage(i);
74 			free(buf);
75 			return nil;
76 		}
77 		maxy = atoi(hdr+0*12);
78 		nb = atoi(hdr+1*12);
79 		if(maxy<=miny || r.max.y<maxy){
80 			werrstr("readimage: bad maxy %d", maxy);
81 			goto Errout;
82 		}
83 		if(nb<=0 || ncblock<nb){
84 			werrstr("readimage: bad count %d", nb);
85 			goto Errout;
86 		}
87 		if(readn(fd, buf, nb)!=nb)
88 			goto Shortread;
89 		if(!new)	/* old image: flip the data bits */
90 			_twiddlecompressed(buf, nb);
91 		cloadmemimage(i, Rect(r.min.x, miny, r.max.x, maxy), buf, nb);
92 		miny = maxy;
93 	}
94 	free(buf);
95 	return i;
96 }