non-blocking fifo read [issue 7]

cava.c

@@ -1,3 +1,8 @@
+/*
+* to keep coherent styling autostyle with:
+* astyle --style=linux --pad-oper --max-code-length=80 --keep-one-line-blocks --keep-one-line-statements --convert-tabs cava.c
+*/
+
 #include <alloca.h>
 #include <stdio.h>
 #include <stdbool.h>
@@ -163,26 +168,42 @@ music(void* data)
 void*
 fifomusic(void* data)
 {
-	FILE *fp;
+        int fd;
-
         int n = 0;
         signed char buf[1024];
         int tempr, templ, lo;
-	int q;
+        int q, i;
+        int t = 0;
         int size = 1024;
         char *path = ((char*)data);
-	fp =  fopen(path, "r");
+        int bytes = 0;
+        int flags;
+        struct timespec req = { .tv_sec = 0, .tv_nsec = 0 };
+
+        req.tv_sec = 0;
+        req.tv_nsec = 10000000;
+
+
+        fd = open(path, O_RDONLY);
+        flags = fcntl(fd, F_GETFL, 0);
+        fcntl(fd, F_SETFL, flags | O_NONBLOCK);
 
         while (1) {
 
-		fread(&buf, sizeof(char), size, fp);
+                bytes = read(fd, buf, sizeof(buf));
 
+                if (bytes == -1) { //if no bytes read sleep 10ms and zero
+                        nanosleep (&req, NULL);
+                        t++;
+                        if (t > 10) {
+                                for (i = 0; i < M; i++)shared[i] = 0;
+                                t = 0;
+                        }
+                } else { //if bytes read go ahead
+                        t = 0;
                         for (q = 0; q < (size / 4); q++) {
-			//printf("%d, %d\n",buf[q],buf[q+1]);
-
                                 tempr = ( buf[size - 4 * q - 1] << 2);
                                 lo =  ( buf[size - 4 * q ] >> 6);
-			//printf("%d\n",buf[4*q+1]);
                                 if (lo < 0)lo = lo + 4;
                                 if (tempr >= 0)tempr = tempr + lo;
                                 if (tempr < 0)tempr = tempr - lo;
@@ -194,14 +215,14 @@ fifomusic(void* data)
                                 if (templ >= 0)templ = templ + lo;
                                 else templ = templ - lo;
 
-			//printf("%d\n",((tempr+templ)/2));
                                 shared[n] = (tempr + templ) / 2;
 
                                 n++;
                                 if (n == M - 1)n = 0;
                         }
                 }
-	fclose(fp);
+        }
+        close(fd);
 }
 
 int main(int argc, char **argv)
@@ -246,7 +267,7 @@ int main(int argc, char **argv)
         struct timespec req = { .tv_sec = 0, .tv_nsec = 0 };
         char *usage =
                 "\nUsage : ./cava [options]\n\nOptions:\n\t-b 1..(console columns/2-1) or 200\t number of bars in the spectrum (default 25 + fills up the console), program wil auto adjust to maxsize if input is to high)\n\n\t-i 'input method'\t\t\t method used for listnening to audio, supports 'alsa' and 'fifo'\n\n\t-d 'alsa device'\t\t\t name of alsa capture device (default 'hw:1,1')\n\n\t-p 'fifo path'\t\t\t\t path to fifo (default '/tmp/mpd.fifo')\n\n\t-c color\t\t\t\t suported colors: red, green, yellow, magenta, cyan, white, blue, black (default: cyan)\n\n\t-C backround color\t\t\t supported colors: same as above (default: no change) \n\n\t-s sensitivity %\t\t\t sensitivity in percent, 0 means no respons 100 is normal 50 half 200 double and so forth\n\n\t-f framerate \t\t\t\t max frames per second to be drawn, if you are experiencing high CPU usage, try redcing this (default: 60)\n\n";
-//**END INIT
+//**END INIT**//
 
         for (i = 0; i < 200; i++) {
                 flast[i] = 0;