use a software volume control over /dev/mixer

manual/shell-fm.1

@@ -115,16 +115,10 @@ Tag the currently played track/artist/album. Tabulator key completes known
 tags.
 .TP
 .B +
-Increase volume (vol).
-.TP
-.B *
-Increase volume (pcm).
+Increase volume.
 .TP
 .B -
-Decrease volume (vol).
-.TP
-.B /
-Decrease volume (pcm).
+Decrease volume.
 .PP
 .SH SETUP
 Before you start, you should have created the directories

source/include/globals.h

@@ -20,11 +20,15 @@ extern int batch;
 /* Forks. */
 extern pid_t playfork, subfork;
 
+extern int playpipe;
+extern unsigned char volume;
+
 extern char * currentStation; /* Name of the current station. */
 
 extern unsigned submitting; /* Number of tracks currently submitted. */
 extern time_t pausetime; /* Pause start time. */
 
+#define MAX_VOLUME 64
 
 extern unsigned flags;
 

source/include/play.h

@@ -7,6 +7,6 @@
 
 #include <stdio.h>
 
-extern int playback(FILE *);
+extern int playback(FILE *, int);
 
 #endif

source/interface.c

@@ -34,7 +34,6 @@
 #include "xmlrpc.h"
 #include "recommend.h"
 #include "util.h"
-#include "mix.h"
 
 #include "globals.h"
 
@@ -215,19 +214,17 @@ void interface(int interactive) {
 				break;
 
 			case '+':
-				adjust(+STEP, VOL);
+				if(volume < MAX_VOLUME)
+					volume += 1;
+				if(playpipe != 0)
+					write(playpipe, &key, 1);
 				break;
 
 			case '-':
-				adjust(-STEP, VOL);
-				break;
-
-			case '*':
-				adjust(+STEP, PCM);
-				break;
-
-			case '/':
-				adjust(-STEP, PCM);
+				if(volume > 0)
+					volume -= 1;
+				if(playpipe != 0)
+					write(playpipe, &key, 1);
 				break;
 
 			case 'u':
@@ -250,9 +247,8 @@ void interface(int interactive) {
 					"r = change radio station          | R = recommend track/artist/album\n"
 					"S = stop                          | s = similiar artist\n"
 					"T = tag track/artist/album        | u = show upcoming tracks in playlist\n"
-					"U = unlove track                  | + = increase volume (vol)\n"
-					"- = decrease volume (vol)         | * = increase volume (pcm)\n"
-					"/ = decrease volume (pcm)\n",
+					"U = unlove track                  | + = increase volume\n"
+					"- = decrease volume\n",
 					stderr
 				);
 				break;

source/play.c

@@ -58,6 +58,7 @@ struct stream {
 
 	FILE * dump;
 	char * path;
+	int pipefd;
 };
 
 #define BUFSIZE (32*1024)
@@ -68,6 +69,8 @@ inline signed scale(mad_fixed_t);
 
 int killed = 0;
 
+unsigned char volume = MAX_VOLUME;
+
 static void sighand(int);
 
 /*
@@ -103,7 +106,7 @@ mkpath(char *path)
 	return (0);
 }
 
-int playback(FILE * streamfd) {
+int playback(FILE * streamfd, int pipefd) {
 	const char * freetrack = NULL;
 
 	killed = 0;
@@ -129,6 +132,8 @@ int playback(FILE * streamfd) {
 
 		data.streamfd = streamfd;
 		data.parent = getppid();
+		data.pipefd = pipefd;
+		fcntl(pipefd, F_SETFL, O_NONBLOCK);
 
 #ifdef LIBAO
 		data.driver_id = ao_default_driver_id();
@@ -298,6 +303,25 @@ static enum mad_flow input(void * data, struct mad_stream * stream) {
 	return MAD_FLOW_CONTINUE;
 }
 
+static void read_from_pipe(int pipefd) {
+	char readchar;
+	ssize_t readcount;
+
+	while((readcount = read(pipefd, &readchar, 1)) > 0) {
+		switch(readchar) {
+			// update this process's copy of the volume level
+			case '+':
+				if(volume < MAX_VOLUME)
+					volume += 1;
+				break;
+			case '-':
+				if(volume > 0)
+					volume -= 1;
+				break;
+		}
+	}
+}
+
 #ifdef LIBAO
 static enum mad_flow output(
 		void * data,
@@ -328,6 +352,7 @@ static enum mad_flow output(
 	stream_ptr = stream = malloc(pcm->length * (pcm->channels == 2 ? 4 : 2));
 
 	assert(stream != NULL);
+	read_from_pipe(ptr->pipefd);
 
 	while(nsample--) {
 		signed int sample;
@@ -373,6 +398,7 @@ static enum mad_flow output(
 	mad_fixed_t * left = pcm->samples[0], * right = pcm->samples[1];
 
 	head = NULL;
+	read_from_pipe(ptr->pipefd);
 
 	arg = rate;
 	ioctl(ptr->audiofd, SOUND_PCM_WRITE_RATE, & arg);
@@ -413,7 +439,7 @@ inline signed scale(register mad_fixed_t sample) {
 	else if(sample < -MAD_F_ONE)
 		sample = -MAD_F_ONE;
 
-	return sample >> (MAD_F_FRACBITS + 1 - 16);
+	return (sample >> (MAD_F_FRACBITS + 1 - 16)) * volume / MAX_VOLUME;
 }
 
 static void sighand(int sig) {

source/service.c

@@ -32,6 +32,7 @@
 struct hash data; /* Warning! MUST be bzero'd ASAP or we're all gonna die! */
 
 pid_t playfork = 0; /* PID of the decoding & playing process, if running */
+int playpipe = 0;
 
 struct playlist playlist;
 char * currentStation = NULL;
@@ -260,9 +261,13 @@ int play(struct playlist * list) {
 	for(i = 0; i < (sizeof(keys) / sizeof(char *)); ++i)
 		set(& track, keys[i], value(& list->track->track, keys[i]));
 
+	int pipefd[2];
+	if(pipe(pipefd) != 0)
+		return !0;
 	playfork = fork();
 
 	if(!playfork) {
+		close(pipefd[1]);
 		FILE * fd = NULL;
 		const char * location = value(& list->track->track, "location");
 
@@ -274,14 +279,19 @@ int play(struct playlist * list) {
 			fetch(location, & fd, NULL, NULL);
 
 			if(fd != NULL) {
-				if(!playback(fd))
+				if(!playback(fd, pipefd[0]))
 					kill(getppid(), SIGUSR2);
+				close(pipefd[0]);
 				fshutdown(& fd);
 			}
 		}
 
 		exit(EXIT_SUCCESS);
 	}
+	close(pipefd[0]);
+	if(playpipe != 0)
+		close(playpipe);
+	playpipe = pipefd[1];
 
 	return !0;
 }