ctl: use automatic variable instead of call of alloca(3)

Inner this library, layouts of all structures are public. At a compilation
time, each size of the structures can be calculated. It means that we can
use automatic variable instead of calling alloca(3) to program this
library because in both ways storages are kept on stack frame of process
VMA. Besides, the usage of automatic variables requires less instructions
than calls of alloca(3). Furthermore, alloca(3) is not described in any
C language standards.

This commit replaces calls of alloca(3) just for structures with automatic
variables, for control features.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/src/control/control.c b/src/control/control.c
index 0cb0105744f6d4468c8a44c991f16a6781cfd026..5c0efc65fb09f73cadfa102c01ab41f70666f410 100644 (file)
--- a/src/control/control.c
+++ b/src/control/control.c
@@ -347,8 +347,8 @@ int snd_ctl_elem_add_integer_set(snd_ctl_t *ctl, snd_ctl_elem_id_t *id,
                                 unsigned int member_count,
                                 long min, long max, long step)
 {
-       snd_ctl_elem_info_t *info;
-       snd_ctl_elem_value_t *data;
+       snd_ctl_elem_info_t info = {0};
+       snd_ctl_elem_value_t data = {0};
        unsigned int i;
        unsigned int j;
        unsigned int numid;
@@ -356,38 +356,36 @@ int snd_ctl_elem_add_integer_set(snd_ctl_t *ctl, snd_ctl_elem_id_t *id,
 
        assert(ctl && id && id->name[0]);
 
-       snd_ctl_elem_info_alloca(&info);
-       info->id = *id;
-       info->type = SND_CTL_ELEM_TYPE_INTEGER;
-       info->access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_USER;
-       info->owner = element_count;
-       info->count = member_count;
-       info->value.integer.min = min;
-       info->value.integer.max = max;
-       info->value.integer.step = step;
-
-       err = ctl->ops->element_add(ctl, info);
+       info.id = *id;
+       info.type = SND_CTL_ELEM_TYPE_INTEGER;
+       info.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_USER;
+       info.owner = element_count;
+       info.count = member_count;
+       info.value.integer.min = min;
+       info.value.integer.max = max;
+       info.value.integer.step = step;
+
+       err = ctl->ops->element_add(ctl, &info);
        if (err < 0)
                return err;
-       numid = snd_ctl_elem_id_get_numid(&info->id);
+       numid = snd_ctl_elem_id_get_numid(&info.id);
 
        /* Set initial value to all of members in all of added elements. */
-       snd_ctl_elem_value_alloca(&data);
-       data->id = info->id;
+       data.id = info.id;
        for (i = 0; i < element_count; i++) {
-               snd_ctl_elem_id_set_numid(&data->id, numid + i);
+               snd_ctl_elem_id_set_numid(&data.id, numid + i);
 
                for (j = 0; j < member_count; j++)
-                       data->value.integer.value[j] = min;
+                       data.value.integer.value[j] = min;
 
-               err = ctl->ops->element_write(ctl, data);
+               err = ctl->ops->element_write(ctl, &data);
                if (err < 0)
                        return err;
        }
 
-       *id = info->id;
+       *id = info.id;
        return 0;
 }
 
@@ -436,8 +434,8 @@ int snd_ctl_elem_add_integer64_set(snd_ctl_t *ctl, snd_ctl_elem_id_t *id,
                                   unsigned int member_count,
                                   long long min, long long max, long long step)
 {
-       snd_ctl_elem_info_t *info;
-       snd_ctl_elem_value_t *data;
+       snd_ctl_elem_info_t info = {0};
+       snd_ctl_elem_value_t data = {0};
        unsigned int i;
        unsigned int j;
        unsigned int numid;
@@ -445,38 +443,36 @@ int snd_ctl_elem_add_integer64_set(snd_ctl_t *ctl, snd_ctl_elem_id_t *id,
 
        assert(ctl && id && id->name[0]);
 
-       snd_ctl_elem_info_alloca(&info);
-       info->id = *id;
-       info->type = SND_CTL_ELEM_TYPE_INTEGER64;
-       info->access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_USER;
-       info->owner = element_count;
-       info->count = member_count;
-       info->value.integer64.min = min;
-       info->value.integer64.max = max;
-       info->value.integer64.step = step;
-
-       err = ctl->ops->element_add(ctl, info);
+       info.id = *id;
+       info.type = SND_CTL_ELEM_TYPE_INTEGER64;
+       info.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_USER;
+       info.owner = element_count;
+       info.count = member_count;
+       info.value.integer64.min = min;
+       info.value.integer64.max = max;
+       info.value.integer64.step = step;
+
+       err = ctl->ops->element_add(ctl, &info);
        if (err < 0)
                return err;
-       numid = snd_ctl_elem_id_get_numid(&info->id);
+       numid = snd_ctl_elem_id_get_numid(&info.id);
 
        /* Set initial value to all of members in all of added elements. */
-       snd_ctl_elem_value_alloca(&data);
-       data->id = info->id;
+       data.id = info.id;
        for (i = 0; i < element_count; i++) {
-               snd_ctl_elem_id_set_numid(&data->id, numid + i);
+               snd_ctl_elem_id_set_numid(&data.id, numid + i);
 
                for (j = 0; j < member_count; j++)
-                       data->value.integer64.value[j] = min;
+                       data.value.integer64.value[j] = min;
 
-               err = ctl->ops->element_write(ctl, data);
+               err = ctl->ops->element_write(ctl, &data);
                if (err < 0)
                        return err;
        }
 
-       *id = info->id;
+       *id = info.id;
        return 0;
 }
 
@@ -520,25 +516,24 @@ int snd_ctl_elem_add_boolean_set(snd_ctl_t *ctl, snd_ctl_elem_id_t *id,
                                 unsigned int element_count,
                                 unsigned int member_count)
 {
-       snd_ctl_elem_info_t *info;
+       snd_ctl_elem_info_t info = {0};
        int err;
 
        assert(ctl && id && id->name[0]);
 
-       snd_ctl_elem_info_alloca(&info);
-       info->id = *id;
-       info->type = SND_CTL_ELEM_TYPE_BOOLEAN;
-       info->access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_USER;
-       info->owner = element_count;
-       info->count = member_count;
-       info->value.integer.min = 0;
-       info->value.integer.max = 1;
-
-       err = ctl->ops->element_add(ctl, info);
+       info.id = *id;
+       info.type = SND_CTL_ELEM_TYPE_BOOLEAN;
+       info.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_USER;
+       info.owner = element_count;
+       info.count = member_count;
+       info.value.integer.min = 0;
+       info.value.integer.max = 1;
+
+       err = ctl->ops->element_add(ctl, &info);
        if (err >= 0)
-               *id = info->id;
+               *id = info.id;
 
        return err;
 }
@@ -590,22 +585,21 @@ int snd_ctl_elem_add_enumerated_set(snd_ctl_t *ctl, snd_ctl_elem_id_t *id,
                                    unsigned int items,
                                    const char *const labels[])
 {
-       snd_ctl_elem_info_t *info;
+       snd_ctl_elem_info_t info = {0};
        unsigned int i, bytes;
        char *buf, *p;
        int err;
 
        assert(ctl && id && id->name[0] && labels);
 
-       snd_ctl_elem_info_alloca(&info);
-       info->id = *id;
-       info->type = SND_CTL_ELEM_TYPE_ENUMERATED;
-       info->access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_USER;
-       info->owner = element_count;
-       info->count = member_count;
-       info->value.enumerated.items = items;
+       info.id = *id;
+       info.type = SND_CTL_ELEM_TYPE_ENUMERATED;
+       info.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_USER;
+       info.owner = element_count;
+       info.count = member_count;
+       info.value.enumerated.items = items;
 
        bytes = 0;
        for (i = 0; i < items; ++i)
@@ -615,17 +609,17 @@ int snd_ctl_elem_add_enumerated_set(snd_ctl_t *ctl, snd_ctl_elem_id_t *id,
        buf = malloc(bytes);
        if (buf == NULL)
                return -ENOMEM;
-       info->value.enumerated.names_ptr = (uintptr_t)buf;
-       info->value.enumerated.names_length = bytes;
+       info.value.enumerated.names_ptr = (uintptr_t)buf;
+       info.value.enumerated.names_length = bytes;
        p = buf;
        for (i = 0; i < items; ++i) {
                strcpy(p, labels[i]);
                p += strlen(labels[i]) + 1;
        }
 
-       err = ctl->ops->element_add(ctl, info);
+       err = ctl->ops->element_add(ctl, &info);
        if (err >= 0)
-               *id = info->id;
+               *id = info.id;
 
        free(buf);
 
@@ -673,23 +667,22 @@ int snd_ctl_elem_add_bytes_set(snd_ctl_t *ctl, snd_ctl_elem_id_t *id,
                               unsigned int element_count,
                               unsigned int member_count)
 {
-       snd_ctl_elem_info_t *info;
+       snd_ctl_elem_info_t info = {0};
        int err;
 
        assert(ctl && id && id->name[0]);
 
-       snd_ctl_elem_info_alloca(&info);
-       info->id = *id;
-       info->type = SND_CTL_ELEM_TYPE_BYTES;
-       info->access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
-                      SNDRV_CTL_ELEM_ACCESS_USER;
-       info->owner = element_count;
-       info->count = member_count;
+       info.id = *id;
+       info.type = SND_CTL_ELEM_TYPE_BYTES;
+       info.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
+                     SNDRV_CTL_ELEM_ACCESS_USER;
+       info.owner = element_count;
+       info.count = member_count;
 
-       err = ctl->ops->element_add(ctl, info);
+       err = ctl->ops->element_add(ctl, &info);
        if (err >= 0)
-               *id = info->id;
+               *id = info.id;
 
        return err;
 }
@@ -705,12 +698,11 @@ int snd_ctl_elem_add_integer(snd_ctl_t *ctl, const snd_ctl_elem_id_t *id,
                             unsigned int member_count,
                             long min, long max, long step)
 {
-       snd_ctl_elem_id_t *local_id;
+       snd_ctl_elem_id_t local_id = {0};
 
-       snd_ctl_elem_id_alloca(&local_id);
-       *local_id = *id;
+       local_id = *id;
 
-       return snd_ctl_elem_add_integer_set(ctl, local_id, 1, member_count,
+       return snd_ctl_elem_add_integer_set(ctl, &local_id, 1, member_count,
                                            min, max, step);
 }
 
@@ -725,12 +717,11 @@ int snd_ctl_elem_add_integer64(snd_ctl_t *ctl, const snd_ctl_elem_id_t *id,
                               unsigned int member_count,
                               long long min, long long max, long long step)
 {
-       snd_ctl_elem_id_t *local_id;
+       snd_ctl_elem_id_t local_id = {0};
 
-       snd_ctl_elem_id_alloca(&local_id);
-       *local_id = *id;
+       local_id = *id;
 
-       return snd_ctl_elem_add_integer64_set(ctl, local_id, 1, member_count,
+       return snd_ctl_elem_add_integer64_set(ctl, &local_id, 1, member_count,
                                              min, max, step);
 }
 
@@ -744,12 +735,11 @@ int snd_ctl_elem_add_integer64(snd_ctl_t *ctl, const snd_ctl_elem_id_t *id,
 int snd_ctl_elem_add_boolean(snd_ctl_t *ctl, const snd_ctl_elem_id_t *id,
                             unsigned int member_count)
 {
-       snd_ctl_elem_id_t *local_id;
+       snd_ctl_elem_id_t local_id = {0};
 
-       snd_ctl_elem_id_alloca(&local_id);
-       *local_id = *id;
+       local_id = *id;
 
-       return snd_ctl_elem_add_boolean_set(ctl, local_id, 1, member_count);
+       return snd_ctl_elem_add_boolean_set(ctl, &local_id, 1, member_count);
 }
 
 /**
@@ -765,12 +755,11 @@ int snd_ctl_elem_add_enumerated(snd_ctl_t *ctl, const snd_ctl_elem_id_t *id,
                                unsigned int member_count, unsigned int items,
                                const char *const labels[])
 {
-       snd_ctl_elem_id_t *local_id;
+       snd_ctl_elem_id_t local_id = {0};
 
-       snd_ctl_elem_id_alloca(&local_id);
-       *local_id = *id;
+       local_id = *id;
 
-       return snd_ctl_elem_add_enumerated_set(ctl, local_id, 1, member_count,
+       return snd_ctl_elem_add_enumerated_set(ctl, &local_id, 1, member_count,
                                               items, labels);
 }
 
@@ -805,15 +794,15 @@ int snd_ctl_elem_add_enumerated(snd_ctl_t *ctl, const snd_ctl_elem_id_t *id,
  */
 int snd_ctl_elem_add_iec958(snd_ctl_t *ctl, const snd_ctl_elem_id_t *id)
 {
-       snd_ctl_elem_info_t *info;
+       snd_ctl_elem_info_t info = {0};
 
        assert(ctl && id && id->name[0]);
-       snd_ctl_elem_info_alloca(&info);
-       info->id = *id;
-       info->type = SND_CTL_ELEM_TYPE_IEC958;
-       info->owner = 1;
-       info->count = 1;
-       return ctl->ops->element_add(ctl, info);
+
+       info.id = *id;
+       info.type = SND_CTL_ELEM_TYPE_IEC958;
+       info.owner = 1;
+       info.count = 1;
+       return ctl->ops->element_add(ctl, &info);
 }
 
 /**

diff --git a/src/control/ctlparse.c b/src/control/ctlparse.c
index d38b44ef986c5c30445a1a20e3d9ea8b766a2439..5c9a168dbd40cc3dcdb064f4927f99c30eaee506 100644 (file)
--- a/src/control/ctlparse.c
+++ b/src/control/ctlparse.c
@@ -312,17 +312,16 @@ int snd_ctl_ascii_value_parse(snd_ctl_t *handle,
                              const char *value)
 {
        const char *ptr = value;
-       snd_ctl_elem_id_t *myid;
+       snd_ctl_elem_id_t myid = {0};
        snd_ctl_elem_type_t type;
        unsigned int idx, count;
        long tmp;
        long long tmp64;
 
-       snd_ctl_elem_id_alloca(&myid);
-       snd_ctl_elem_info_get_id(info, myid);
+       snd_ctl_elem_info_get_id(info, &myid);
        type = snd_ctl_elem_info_get_type(info);
        count = snd_ctl_elem_info_get_count(info);
-       snd_ctl_elem_value_set_id(dst, myid);
+       snd_ctl_elem_value_set_id(dst, &myid);
        
        for (idx = 0; idx < count && idx < 128 && ptr && *ptr; idx++) {
                if (*ptr == ',')

diff --git a/src/control/namehint.c b/src/control/namehint.c
index ad8dda37a6370ceab8199b9944bee812d671bc40..4dbd2163cbc98a80f8b5bfef0ee21656495f15a1 100644 (file)
--- a/src/control/namehint.c
+++ b/src/control/namehint.c
@@ -97,45 +97,42 @@ static int get_dev_name1(struct hint_list *list, char **res, int device,
 #ifdef BUILD_HWDEP
        case SND_CTL_ELEM_IFACE_HWDEP:
                {
-                       snd_hwdep_info_t *info;
-                       snd_hwdep_info_alloca(&info);
-                       snd_hwdep_info_set_device(info, device);
-                       if (snd_ctl_hwdep_info(list->ctl, info) < 0)
+                       snd_hwdep_info_t info = {0};
+                       snd_hwdep_info_set_device(&info, device);
+                       if (snd_ctl_hwdep_info(list->ctl, &info) < 0)
                                return 0;
-                       *res = strdup(snd_hwdep_info_get_name(info));
+                       *res = strdup(snd_hwdep_info_get_name(&info));
                        return 0;
                }
 #endif
 #ifdef BUILD_PCM
        case SND_CTL_ELEM_IFACE_PCM:
                {
-                       snd_pcm_info_t *info;
-                       snd_pcm_info_alloca(&info);
-                       snd_pcm_info_set_device(info, device);
-                       snd_pcm_info_set_stream(info, stream ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK);
-                       if (snd_ctl_pcm_info(list->ctl, info) < 0)
+                       snd_pcm_info_t info = {0};
+                       snd_pcm_info_set_device(&info, device);
+                       snd_pcm_info_set_stream(&info, stream ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK);
+                       if (snd_ctl_pcm_info(list->ctl, &info) < 0)
                                return 0;
-                       switch (snd_pcm_info_get_class(info)) {
+                       switch (snd_pcm_info_get_class(&info)) {
                        case SND_PCM_CLASS_MODEM:
                        case SND_PCM_CLASS_DIGITIZER:
                                return -ENODEV;
                        default:
                                break;
                        }
-                       *res = strdup(snd_pcm_info_get_name(info));
+                       *res = strdup(snd_pcm_info_get_name(&info));
                        return 0;
                }
 #endif
 #ifdef BUILD_RAWMIDI
        case SND_CTL_ELEM_IFACE_RAWMIDI:
                {
-                       snd_rawmidi_info_t *info;
-                       snd_rawmidi_info_alloca(&info);
-                       snd_rawmidi_info_set_device(info, device);
-                       snd_rawmidi_info_set_stream(info, stream ? SND_RAWMIDI_STREAM_INPUT : SND_RAWMIDI_STREAM_OUTPUT);
-                       if (snd_ctl_rawmidi_info(list->ctl, info) < 0)
+                       snd_rawmidi_info_t info = {0};
+                       snd_rawmidi_info_set_device(&info, device);
+                       snd_rawmidi_info_set_stream(&info, stream ? SND_RAWMIDI_STREAM_INPUT : SND_RAWMIDI_STREAM_OUTPUT);
+                       if (snd_ctl_rawmidi_info(list->ctl, &info) < 0)
                                return 0;
-                       *res = strdup(snd_rawmidi_info_get_name(info));
+                       *res = strdup(snd_rawmidi_info_get_name(&info));
                        return 0;
                }
 #endif
@@ -419,11 +416,10 @@ static int add_card(snd_config_t *config, snd_config_t *rw_config, struct hint_l
        snd_config_iterator_t i, next;
        const char *str;
        char ctl_name[16];
-       snd_ctl_card_info_t *info;
+       snd_ctl_card_info_t info = {0};
        int device, max_device = 0;
        
-       snd_ctl_card_info_alloca(&info);
-       list->info = info;
+       list->info = &info;
        err = snd_config_search(config, list->siface, &conf);
        if (err < 0)
                return err;
@@ -431,7 +427,7 @@ static int add_card(snd_config_t *config, snd_config_t *rw_config, struct hint_l
        err = snd_ctl_open(&list->ctl, ctl_name, 0);
        if (err < 0)
                return err;
-       err = snd_ctl_card_info(list->ctl, info);
+       err = snd_ctl_card_info(list->ctl, &info);
        if (err < 0)
                goto __error;
        snd_config_for_each(i, next, conf) {

diff --git a/src/control/setup.c b/src/control/setup.c
index f23bf2c90bce7471aa741c7d90961aad7a2b1420..c598c8bf982e5d0948abe454ca8bd7a77950490c 100644 (file)
--- a/src/control/setup.c
+++ b/src/control/setup.c
@@ -252,13 +252,12 @@ static int snd_config_get_ctl_elem_value(snd_config_t *conf,
 {
        int err;
        snd_config_iterator_t i, next;
-       snd_ctl_elem_id_t *id;
+       snd_ctl_elem_id_t id = {0};
        snd_ctl_elem_type_t type;
        unsigned int count;
        long v;
        long idx;
-       snd_ctl_elem_id_alloca(&id);
-       snd_ctl_elem_value_get_id(val, id);
+       snd_ctl_elem_value_get_id(val, &id);
        count = snd_ctl_elem_info_get_count(info);
        type = snd_ctl_elem_info_get_type(info);
        if (count == 1) {

diff --git a/src/control/tlv.c b/src/control/tlv.c
index b08d88722f15dd78fa824e35a5bbf2dffa89b4db..6ad64a18938067e53c57a72b5cf44d783e6187e8 100644 (file)
--- a/src/control/tlv.c
+++ b/src/control/tlv.c
@@ -409,20 +409,19 @@ struct tlv_info {
 static int get_tlv_info(snd_ctl_t *ctl, const snd_ctl_elem_id_t *id,
                        struct tlv_info *rec)
 {
-       snd_ctl_elem_info_t *info;
+       snd_ctl_elem_info_t info = {0};
        int err;
 
-       snd_ctl_elem_info_alloca(&info);
-       snd_ctl_elem_info_set_id(info, id);
-       err = snd_ctl_elem_info(ctl, info);
+       snd_ctl_elem_info_set_id(&info, id);
+       err = snd_ctl_elem_info(ctl, &info);
        if (err < 0)
                return err;
-       if (!snd_ctl_elem_info_is_tlv_readable(info))
+       if (!snd_ctl_elem_info_is_tlv_readable(&info))
                return -EINVAL;
-       if (snd_ctl_elem_info_get_type(info) != SND_CTL_ELEM_TYPE_INTEGER)
+       if (snd_ctl_elem_info_get_type(&info) != SND_CTL_ELEM_TYPE_INTEGER)
                return -EINVAL;
-       rec->minval = snd_ctl_elem_info_get_min(info);
-       rec->maxval = snd_ctl_elem_info_get_max(info);
+       rec->minval = snd_ctl_elem_info_get_min(&info);
+       rec->maxval = snd_ctl_elem_info_get_max(&info);
        err = snd_ctl_elem_tlv_read(ctl, id, rec->buf, sizeof(rec->buf));
        if (err < 0)
                return err;