From: Clemens Ladisch <clemens@ladisch.de>
Date: Mon, 12 Nov 2007 07:50:08 +0000 (+0100)
Subject: simple mixer: fix calculation of control range
X-Git-Tag: v1.0.16rc1~52
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=7b51f627326569c38e85af224de21be36cb6562b;p=alsa-lib.git

simple mixer: fix calculation of control range

When calculating the value range of a control, the variables cannot be
initialized with zero because this would prevent the minimum from having
a value above zero or the maximum from having a value below zero.
---

diff --git a/src/mixer/simple_none.c b/src/mixer/simple_none.c
index 6b015af1..b490e1c1 100644
--- a/src/mixer/simple_none.c
+++ b/src/mixer/simple_none.c
@@ -37,6 +37,7 @@
 #include <sys/ioctl.h>
 #include <assert.h>
 #include <math.h>
+#include <limits.h>
 #include <alsa/asoundlib.h>
 #include "mixer_simple.h"
 
@@ -672,9 +673,11 @@ static int simple_update(snd_mixer_elem_t *melem)
 
 	caps = 0;
 	pchannels = 0;
-	pmin = pmax = 0;
+	pmin = LONG_MAX;
+	pmax = LONG_MIN;
 	cchannels = 0;
-	cmin = cmax = 0;
+	cmin = LONG_MAX;
+	cmax = LONG_MIN;
 	assert(snd_mixer_elem_get_type(melem) == SND_MIXER_ELEM_SIMPLE);
 	simple = snd_mixer_elem_get_private(melem);
 	name = snd_mixer_selem_get_name(melem);
@@ -868,13 +871,13 @@ static int simple_update(snd_mixer_elem_t *melem)
 	simple->selem.caps = caps;
 	simple->str[SM_PLAY].channels = pchannels;
 	if (!simple->str[SM_PLAY].range) {
-		simple->str[SM_PLAY].min = pmin;
-		simple->str[SM_PLAY].max = pmax;
+		simple->str[SM_PLAY].min = pmin != LONG_MAX ? pmin : 0;
+		simple->str[SM_PLAY].max = pmax != LONG_MIN ? pmax : 0;
 	}
 	simple->str[SM_CAPT].channels = cchannels;
 	if (!simple->str[SM_CAPT].range) {
-		simple->str[SM_CAPT].min = cmin;
-		simple->str[SM_CAPT].max = cmax;
+		simple->str[SM_CAPT].min = cmin != LONG_MAX ? cmin : 0;
+		simple->str[SM_CAPT].max = cmax != LONG_MIN ? cmax : 0;
 	}
 	return 0;
 }