mixer.c

/* mixer.c
**
** Copyright 2011, The Android Open Source Project
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are met:
**     * Redistributions of source code must retain the above copyright
**       notice, this list of conditions and the following disclaimer.
**     * Redistributions in binary form must reproduce the above copyright
**       notice, this list of conditions and the following disclaimer in the
**       documentation and/or other materials provided with the distribution.
**     * Neither the name of The Android Open Source Project nor the names of
**       its contributors may be used to endorse or promote products derived
**       from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY The Android Open Source Project ``AS IS'' AND
** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
** ARE DISCLAIMED. IN NO EVENT SHALL The Android Open Source Project BE LIABLE
** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
** SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
** DAMAGE.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>

#include <linux/ioctl.h>
#define __force
#define __bitwise
#define __user
#include <sound/asound.h>

#include <tinyalsa/asoundlib.h>

static const char *elem_iface_name(snd_ctl_elem_iface_t n)
{
    switch (n) {
    case SNDRV_CTL_ELEM_IFACE_CARD: return "CARD";
    case SNDRV_CTL_ELEM_IFACE_HWDEP: return "HWDEP";
    case SNDRV_CTL_ELEM_IFACE_MIXER: return "MIXER";
    case SNDRV_CTL_ELEM_IFACE_PCM: return "PCM";
    case SNDRV_CTL_ELEM_IFACE_RAWMIDI: return "MIDI";
    case SNDRV_CTL_ELEM_IFACE_TIMER: return "TIMER";
    case SNDRV_CTL_ELEM_IFACE_SEQUENCER: return "SEQ";
    default: return "???";
    }
}

static const char *elem_type_name(snd_ctl_elem_type_t n)
{
    switch (n) {
    case SNDRV_CTL_ELEM_TYPE_NONE: return "NONE";
    case SNDRV_CTL_ELEM_TYPE_BOOLEAN: return "BOOL";
    case SNDRV_CTL_ELEM_TYPE_INTEGER: return "INT32";
    case SNDRV_CTL_ELEM_TYPE_ENUMERATED: return "ENUM";
    case SNDRV_CTL_ELEM_TYPE_BYTES: return "BYTES";
    case SNDRV_CTL_ELEM_TYPE_IEC958: return "IEC958";
    case SNDRV_CTL_ELEM_TYPE_INTEGER64: return "INT64";
    default: return "???";
    }
}


struct mixer_ctl {
    struct mixer *mixer;
    struct snd_ctl_elem_info *info;
    char **ename;
};

struct mixer {
    int fd;
    struct snd_ctl_elem_info *info;
    struct mixer_ctl *ctl;
    unsigned int count;
};

void mixer_close(struct mixer *mixer)
{
    unsigned int n,m;

    if (mixer->fd >= 0)
        close(mixer->fd);

    if (mixer->ctl) {
        for (n = 0; n < mixer->count; n++) {
            if (mixer->ctl[n].ename) {
                unsigned int max = mixer->ctl[n].info->value.enumerated.items;
                for (m = 0; m < max; m++)
                    free(mixer->ctl[n].ename[m]);
                free(mixer->ctl[n].ename);
            }
        }
        free(mixer->ctl);
    }

    if (mixer->info)
        free(mixer->info);

    free(mixer);

    /* TODO: verify frees */
}

struct mixer *mixer_open(unsigned int device)
{
    struct snd_ctl_elem_list elist;
    struct snd_ctl_elem_info tmp;
    struct snd_ctl_elem_id *eid = NULL;
    struct mixer *mixer = NULL;
    unsigned int n, m;
    int fd;

    fd = open("/dev/snd/controlC0", O_RDWR);
    if (fd < 0)
        return 0;

    memset(&elist, 0, sizeof(elist));
    if (ioctl(fd, SNDRV_CTL_IOCTL_ELEM_LIST, &elist) < 0)
        goto fail;

    mixer = calloc(1, sizeof(*mixer));
    if (!mixer)
        goto fail;

    mixer->ctl = calloc(elist.count, sizeof(struct mixer_ctl));
    mixer->info = calloc(elist.count, sizeof(struct snd_ctl_elem_info));
    if (!mixer->ctl || !mixer->info)
        goto fail;

    eid = calloc(elist.count, sizeof(struct snd_ctl_elem_id));
    if (!eid)
        goto fail;

    mixer->count = elist.count;
    mixer->fd = fd;
    elist.space = mixer->count;
    elist.pids = eid;
    if (ioctl(fd, SNDRV_CTL_IOCTL_ELEM_LIST, &elist) < 0)
        goto fail;

    for (n = 0; n < mixer->count; n++) {
        struct snd_ctl_elem_info *ei = mixer->info + n;
        ei->id.numid = eid[n].numid;
        if (ioctl(fd, SNDRV_CTL_IOCTL_ELEM_INFO, ei) < 0)
            goto fail;
        mixer->ctl[n].info = ei;
        mixer->ctl[n].mixer = mixer;
        if (ei->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
            char **enames = calloc(ei->value.enumerated.items, sizeof(char*));
            if (!enames)
                goto fail;
            mixer->ctl[n].ename = enames;
            for (m = 0; m < ei->value.enumerated.items; m++) {
                memset(&tmp, 0, sizeof(tmp));
                tmp.id.numid = ei->id.numid;
                tmp.value.enumerated.item = m;
                if (ioctl(fd, SNDRV_CTL_IOCTL_ELEM_INFO, &tmp) < 0)
                    goto fail;
                enames[m] = strdup(tmp.value.enumerated.name);
                if (!enames[m])
                    goto fail;
            }
        }
    }

    free(eid);
    return mixer;

fail:
    /* TODO: verify frees in failure case */
    if (eid)
        free(eid);
    if (mixer)
        mixer_close(mixer);
    else if (fd >= 0)
        close(fd);
    return 0;
}

int mixer_get_num_ctls(struct mixer *mixer)
{
    return mixer->count;
}

struct mixer_ctl *mixer_get_ctl(struct mixer *mixer, unsigned int id)
{
    if (id < mixer->count)
        return mixer->ctl + id;

    return NULL;
}

struct mixer_ctl *mixer_get_ctl_by_name(struct mixer *mixer, const char *name)
{
    unsigned int n;
    for (n = 0; n < mixer->count; n++)
        if (!strcmp(name, (char*) mixer->info[n].id.name))
            return mixer->ctl + n;

    return NULL;
}

static int percent_to_int(struct snd_ctl_elem_info *ei, int percent)
{
    int range;
    
    if (percent > 100)
        percent = 100;
    else if (percent < 0)
        percent = 0;
    
    range = (ei->value.integer.max - ei->value.integer.min);
    
    return ei->value.integer.min + (range * percent) / 100;
}

static int int_to_percent(struct snd_ctl_elem_info *ei, int value)
{
    int range = (ei->value.integer.max - ei->value.integer.min);
    
    if (range == 0)
        return 0;
    
    return ((value - ei->value.integer.min) / range) * 100;
}

int mixer_ctl_get_percent(struct mixer_ctl *ctl)
{
    struct snd_ctl_elem_value ev;

    memset(&ev, 0, sizeof(ev));
    ev.id.numid = ctl->info->id.numid;
    if (ioctl(ctl->mixer->fd, SNDRV_CTL_IOCTL_ELEM_READ, &ev))
        return -1;

    switch (ctl->info->type) {
    case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
        return !!ev.value.integer.value[0]; /* TODO: handle multiple return values */
        break;
    case SNDRV_CTL_ELEM_TYPE_INTEGER: {
        return int_to_percent(ctl->info, ev.value.integer.value[0]);
        break;
    }
    default:
        errno = EINVAL;
        return -1;
    }

    return 0;
}

int mixer_ctl_set_percent(struct mixer_ctl *ctl, int percent)
{
    struct snd_ctl_elem_value ev;
    unsigned int n;

    memset(&ev, 0, sizeof(ev));
    ev.id.numid = ctl->info->id.numid;
    switch (ctl->info->type) {
    case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
        for (n = 0; n < ctl->info->count; n++)
            ev.value.integer.value[n] = !!percent; /* TODO: handle multiple set values */
        break;

    case SNDRV_CTL_ELEM_TYPE_INTEGER: {
        int value = percent_to_int(ctl->info, percent);
        for (n = 0; n < ctl->info->count; n++)
            ev.value.integer.value[n] = value;
        break;
    }

    default:
        errno = EINVAL;
        return -1;
    }
    
    return ioctl(ctl->mixer->fd, SNDRV_CTL_IOCTL_ELEM_WRITE, &ev);
}

int mixer_ctl_set_enum(struct mixer_ctl *ctl, unsigned int id)
{
    struct snd_ctl_elem_value ev;

    if ((ctl->info->type != SNDRV_CTL_ELEM_TYPE_ENUMERATED) ||
        (id >= ctl->info->value.enumerated.items)) {
        errno = EINVAL;
        return -1;
    }

    memset(&ev, 0, sizeof(ev));
    ev.value.enumerated.item[0] = id;
    ev.id.numid = ctl->info->id.numid;
    if (ioctl(ctl->mixer->fd, SNDRV_CTL_IOCTL_ELEM_WRITE, &ev) < 0)
        return -1;
    return 0;
}

int mixer_ctl_set_enum_by_name(struct mixer_ctl *ctl, const char *string)
{
    unsigned int n, max;
    struct snd_ctl_elem_value ev;
    
    if (ctl->info->type != SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
        errno = EINVAL;
        return -1;
    }
    
    max = ctl->info->value.enumerated.items;
    for (n = 0; n < max; n++) {
        if (!strcmp(string, ctl->ename[n])) {
            memset(&ev, 0, sizeof(ev));
            ev.value.enumerated.item[0] = n;
            ev.id.numid = ctl->info->id.numid;
            if (ioctl(ctl->mixer->fd, SNDRV_CTL_IOCTL_ELEM_WRITE, &ev) < 0)
                return -1;
            return 0;
        }
    }
    
    errno = EINVAL;
    return -1;
}