1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 
5 static char channames[] = "rgbkamx";
6 char*
7 chantostr(char *buf, u32int cc)
8 {
9 	u32int c, rc;
10 	char *p;
11 
12 	if(chantodepth(cc) == 0)
13 		return nil;
14 
15 	/* reverse the channel descriptor so we can easily generate the string in the right order */
16 	rc = 0;
17 	for(c=cc; c; c>>=8){
18 		rc <<= 8;
19 		rc |= c&0xFF;
20 	}
21 
22 	p = buf;
23 	for(c=rc; c; c>>=8) {
24 		*p++ = channames[TYPE(c)];
25 		*p++ = '0'+NBITS(c);
26 	}
27 	*p = 0;
28 
29 	return buf;
30 }
31 
32 u32int
33 strtochan(char *s)
34 {
35 	char *p, *q;
36 	u32int c;
37 	int t, n;
38 
39 	c = 0;
40 	p=s;
41 	while(*p && isspace((uchar)*p))
42 		p++;
43 
44 	while(*p && !isspace((uchar)*p)){
45 		if((q = strchr(channames, p[0])) == nil)
46 			return 0;
47 		t = q-channames;
48 		if(p[1] < '0' || p[1] > '9')
49 			return 0;
50 		n = p[1]-'0';
51 		c = (c<<8) | __DC(t, n);
52 		p += 2;
53 	}
54 	return c;
55 }
56 
57 int
58 chantodepth(u32int c)
59 {
60 	int n;
61 
62 	for(n=0; c; c>>=8){
63 		if(TYPE(c) >= NChan || NBITS(c) > 8 || NBITS(c) <= 0)
64 			return 0;
65 		n += NBITS(c);
66 	}
67 	if(n==0 || (n>8 && n%8) || (n<8 && 8%n))
68 		return 0;
69 	return n;
70 }