ref: c11957a7915d355d80ff7e6a21721ba05441ca29
dir: /libdraw/chan.c/
#include "lib9.h" #include "draw.h" static char channames[] = "rgbkamx"; char* chantostr(char *buf, u32 cc) { u32 c, rc; char *p; if(chantodepth(cc) == 0) return nil; /* reverse the channel descriptor so we can easily generate the string in the right order */ rc = 0; for(c=cc; c; c>>=8){ rc <<= 8; rc |= c&0xFF; } p = buf; for(c=rc; c; c>>=8) { *p++ = channames[TYPE(c)]; *p++ = '0'+NBITS(c); } *p = 0; return buf; } /* avoid pulling in ctype when using with drawterm etc. */ static int iswhitespace(char c) { return c==' ' || c== '\t' || c=='\r' || c=='\n'; } u32 strtochan(char *s) { char *p, *q; u32 c; int t, n; c = 0; p=s; while(*p && iswhitespace(*p)) p++; while(*p && !iswhitespace(*p)){ if((q = strchr(channames, p[0])) == nil) return 0; t = q-channames; if(p[1] < '0' || p[1] > '9') return 0; n = p[1]-'0'; c = (c<<8) | __DC(t, n); p += 2; } return c; } int chantodepth(u32 c) { int n; for(n=0; c; c>>=8){ if(TYPE(c) >= NChan || NBITS(c) > 8 || NBITS(c) <= 0) return 0; n += NBITS(c); } if(n==0 || (n>8 && n%8) || (n<8 && 8%n)) return 0; return n; }