[alsa-devel] [PATCH 34/34] alisp: remove alloca() from FA_pcm_info()

[Takashi Sakamoto]

Both of alloca() and automatic variables keeps storages on stack, while
the former generates more instructions than the latter. It's better to use
the latter if the size of storage is computable at pre-compile or compile
time; i.e. just for structures.

This commit obsolete usages of alloca() with automatic variables.

Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 src/alisp/alisp_snd.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/src/alisp/alisp_snd.c b/src/alisp/alisp_snd.c
index 72c6ab0..c5e96e8 100644
--- a/src/alisp/alisp_snd.c
+++ b/src/alisp/alisp_snd.c
@@ -749,7 +749,7 @@ static struct alisp_object * FA_pcm_info(struct alisp_instance * instance, struc
 {
 	snd_pcm_t *handle;
 	struct alisp_object * lexpr, * p1;
-	snd_pcm_info_t *info;
+	snd_pcm_info_t info = {0};
 	int err;
 
 	p1 = eval(instance, car(args));
@@ -758,22 +758,21 @@ static struct alisp_object * FA_pcm_info(struct alisp_instance * instance, struc
 	handle = (snd_pcm_t *)get_ptr(instance, p1, item->prefix);
 	if (handle == NULL)
 		return &alsa_lisp_nil;
-	snd_pcm_info_alloca(&info);
-	err = snd_pcm_info(handle, info);
+	err = snd_pcm_info(handle, &info);
 	lexpr = new_lexpr(instance, err);
 	if (err < 0)
 		return lexpr;
-	p1 = add_cons(instance, lexpr->value.c.cdr, 0, "card", new_integer(instance, snd_pcm_info_get_card(info)));
-	p1 = add_cons(instance, p1, 1, "device", new_integer(instance, snd_pcm_info_get_device(info)));
-	p1 = add_cons(instance, p1, 1, "subdevice", new_integer(instance, snd_pcm_info_get_subdevice(info)));
-	p1 = add_cons(instance, p1, 1, "id", new_string(instance, snd_pcm_info_get_id(info)));
-	p1 = add_cons(instance, p1, 1, "name", new_string(instance, snd_pcm_info_get_name(info)));
-	p1 = add_cons(instance, p1, 1, "subdevice_name", new_string(instance, snd_pcm_info_get_subdevice_name(info)));
-	p1 = add_cons(instance, p1, 1, "class", new_integer(instance, snd_pcm_info_get_class(info)));
-	p1 = add_cons(instance, p1, 1, "subclass", new_integer(instance, snd_pcm_info_get_subclass(info)));
-	p1 = add_cons(instance, p1, 1, "subdevices_count", new_integer(instance, snd_pcm_info_get_subdevices_count(info)));
-	p1 = add_cons(instance, p1, 1, "subdevices_avail", new_integer(instance, snd_pcm_info_get_subdevices_avail(info)));
-	//p1 = add_cons(instance, p1, 1, "sync", new_string(instance, snd_pcm_info_get_sync(info)));
+	p1 = add_cons(instance, lexpr->value.c.cdr, 0, "card", new_integer(instance, snd_pcm_info_get_card(&info)));
+	p1 = add_cons(instance, p1, 1, "device", new_integer(instance, snd_pcm_info_get_device(&info)));
+	p1 = add_cons(instance, p1, 1, "subdevice", new_integer(instance, snd_pcm_info_get_subdevice(&info)));
+	p1 = add_cons(instance, p1, 1, "id", new_string(instance, snd_pcm_info_get_id(&info)));
+	p1 = add_cons(instance, p1, 1, "name", new_string(instance, snd_pcm_info_get_name(&info)));
+	p1 = add_cons(instance, p1, 1, "subdevice_name", new_string(instance, snd_pcm_info_get_subdevice_name(&info)));
+	p1 = add_cons(instance, p1, 1, "class", new_integer(instance, snd_pcm_info_get_class(&info)));
+	p1 = add_cons(instance, p1, 1, "subclass", new_integer(instance, snd_pcm_info_get_subclass(&info)));
+	p1 = add_cons(instance, p1, 1, "subdevices_count", new_integer(instance, snd_pcm_info_get_subdevices_count(&info)));
+	p1 = add_cons(instance, p1, 1, "subdevices_avail", new_integer(instance, snd_pcm_info_get_subdevices_avail(&info)));
+	//p1 = add_cons(instance, p1, 1, "sync", new_string(instance, snd_pcm_info_get_sync(&info)));
 	return lexpr;
 }
 
-- 
2.7.4