add adj-balance verb for incremental balance changes

This is useful if you ever wanted to script balance adjustment, since it
would otherwise require 2 invocations (get + set).

3 files changed, 17 insertions, 2 deletions

diff --git a/pulsemix.1 b/pulsemix.1
index f06e9b7..3665078 100644
--- a/pulsemix.1
+++ b/pulsemix.1
@@ -39,6 +39,10 @@ Get the balance of the target.
 .IP "\fBset-balance\fR \fIVALUE\fR"
 Set the balance of the target. VALUE is an integer from -100 (all left) to 100
 (all right).
+.IP "\fBadj-balance\fR \fIVALUE\fR"
+Adjust balance by the integer increment VALUE. The resulting balance has the same
+bounds as those set by \fBset-balance\fR. The end-of-options indicator (\fI--\fR) is
+required when passing a negative increment.
 .IP "\fBincrease\fR \fIVALUE\fR"
 Increase the volume percentage of target device or application by integer
 VALUE. Increasing the volume in this way is capped at 100.
diff --git a/pulsemix.c b/pulsemix.c
index 3795e1e..9a3484a 100644
--- a/pulsemix.c
+++ b/pulsemix.c
@@ -65,6 +65,7 @@ enum action {
 	ACTION_SETVOL,
 	ACTION_GETBAL,
 	ACTION_SETBAL,
+	ACTION_ADJBAL,
 	ACTION_INCREASE,
 	ACTION_DECREASE,
 	ACTION_MUTE,
@@ -626,6 +627,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
 	fputs("  set-volume VALUE       set volume for device\n", out);
 	fputs("  get-balance            get balance for device\n", out);
 	fputs("  set-balance VALUE      set balance for device\n", out);
+	fputs("  adj-balance VALUE      increase or decrease balance for device\n", out);
 	fputs("  increase VALUE         increase volume\n", out);
 	fputs("  decrease VALUE         decrease volume\n", out);
 	fputs("  mute                   mute device\n", out);
@@ -658,6 +660,8 @@ static enum action string_to_verb(const char *string)
 		return ACTION_GETBAL;
 	else if (strcmp(string, "set-balance") == 0)
 		return ACTION_SETBAL;
+	else if (strcmp(string, "adj-balance") == 0)
+		return ACTION_ADJBAL;
 	else if (strcmp(string, "increase") == 0)
 		return ACTION_INCREASE;
 	else if (strcmp(string, "decrease") == 0)
@@ -692,8 +696,10 @@ static int do_verb(struct pulseaudio_t *pulse, enum action verb, int value)
 		printf("%d\n", pulse->head->balance);
 		return 0;
 	case ACTION_SETBAL:
+		return set_balance(pulse, pulse->head, CLAMP(value, -100, 100));
+	case ACTION_ADJBAL:
 		return set_balance(pulse, pulse->head,
-				CLAMP(value, -100, 100));
+				CLAMP(pulse->head->balance + value, -100, 100));
 	case ACTION_INCREASE:
 		return set_volume(pulse, pulse->head,
 				CLAMP(pulse->head->volume_percent + value, 0, 100));
@@ -781,6 +787,7 @@ int main(int argc, char *argv[])
 	switch (verb) {
 	case ACTION_SETVOL:
 	case ACTION_SETBAL:
+	case ACTION_ADJBAL:
 	case ACTION_INCREASE:
 	case ACTION_DECREASE:
 		if (optind == argc)
diff --git a/runtests b/runtests
index 7225d07..b2fb861 100755
--- a/runtests
+++ b/runtests
@@ -19,7 +19,7 @@ do_test() {
 
   (( ++testno ))
 
-  result=$("$pulsemix" "$verb" ${arg+"$arg"} 2>/dev/null)
+  result=$("$pulsemix" "$verb" -- ${arg+"$arg"} 2>/dev/null)
   if [[ $result != $expected ]]; then
     printf '==> test %d FAIL: expected %s, got %s\n' "$testno" "$expected" "$result"
     (( ++fail ))
@@ -40,7 +40,11 @@ do_test '' 'decrease' bar
 
 # balance
 do_test 30 'set-balance' 30
+do_test 30 'get-balance'
 do_test 100 'set-balance' 9001
+do_test -5 'adj-balance' -105
+do_test 45 'adj-balance' 50
+do_test 100 'adj-balance' 9001
 do_test 0 'set-balance' 0
 
 if (( ! fail )); then