color_reader.c

   1 #include <unistd.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <ctype.h>
   5 #include <fcntl.h>
   6 #include <termios.h>
   7 #include <string.h>
   8 #include <sys/select.h>
   9 #include "rgb.h"
  10 #include "color_reader.h"
  11
  12 #ifndef XCASE
  13 #define XCASE 0
  14 #endif
  15
  16 static int byte_from_hex(const char* s, unsigned char* out) {
  17         static const char hex[] = "0123456789abcdef";
  18         char* h1 = strchr(hex, s[0]);
  19         char* h2 = strchr(hex, s[1]);
  20         if(!h1 || !h2) return 1;
  21         *out = ((h1 - hex) << 4) | (h2 - hex);
  22         return 0;
  23 }
  24
  25 int color_reader_init(struct color_reader *cr) {
  26         if(-1==(cr->fd = open("/dev/tty", O_RDWR|O_CLOEXEC))) return 1;
  27         if(-1==tcgetattr(cr->fd, &cr->t)) goto err;
  28         struct termios new = cr->t;
  29         new.c_iflag = 0;
  30         new.c_oflag &= ~OPOST;
  31         new.c_lflag &= ~(ISIG | ICANON | ECHO | XCASE);
  32         new.c_cc[VMIN] = 0;
  33         new.c_cc[VTIME] = 0;
  34         if(-1==tcsetattr(cr->fd, TCSAFLUSH, &new)) goto err;
  35         tcdrain(cr->fd);
  36         return 0;
  37 err:
  38         close(cr->fd);
  39         return 1;
  40 }
  41
  42 int color_reader_get_color(struct color_reader *cr, int colnr, rgb_t*out) {
  43         char buf[128], *p;
  44         unsigned l;
  45         fd_set reed;
  46
  47         dprintf(cr->fd, "\x1b]4;%d;?\x1b\x5c", colnr);
  48         FD_ZERO(&reed);
  49         FD_SET(cr->fd, &reed);
  50         while(select(cr->fd+1, &reed, 0, 0, 0)<=0);
  51         for(l=0,p=buf;l<sizeof(buf);l++,p++) {
  52                 ssize_t rd;
  53                 if(1==(rd=read(cr->fd, p, 1))) continue;
  54                 if(rd < 0) return 2;
  55         }
  56         if(l<23) return 3;
  57         *p = 0, p = buf;
  58         if(memcmp(p,"\x1b]4;",4)) return 4;
  59         p+=4;l-=4;
  60         while(l>4 && memcmp(p,"rgb:",4)) p++,l--;
  61         p+=4;l-=4;
  62         if(l<14) return 5;
  63         if(byte_from_hex(p, &out->r)) return 6;
  64         p+=5;
  65         if(byte_from_hex(p, &out->g)) return 7;
  66         p+=5;
  67         if(byte_from_hex(p, &out->b)) return 8;
  68         return 0;
  69 }
  70 int color_reader_close(struct color_reader *cr) {
  71         int err = 0;
  72         if(tcsetattr(cr->fd, TCSAFLUSH, &cr->t)==-1) err=1;
  73         close(cr->fd);
  74         return err;
  75 }