diff options
Diffstat (limited to 'src/pcm.c')
-rw-r--r-- | src/pcm.c | 152 |
1 files changed, 113 insertions, 39 deletions
@@ -64,6 +64,11 @@ static inline int param_is_interval(int p) (p <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL); } +static inline const struct snd_interval *param_get_interval(const struct snd_pcm_hw_params *p, int n) +{ + return &(p->intervals[n - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]); +} + static inline struct snd_interval *param_to_interval(struct snd_pcm_hw_params *p, int n) { return &(p->intervals[n - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]); @@ -94,19 +99,19 @@ static void param_set_min(struct snd_pcm_hw_params *p, int n, unsigned int val) } } -static unsigned int param_get_min(struct snd_pcm_hw_params *p, int n) +static unsigned int param_get_min(const struct snd_pcm_hw_params *p, int n) { if (param_is_interval(n)) { - struct snd_interval *i = param_to_interval(p, n); + const struct snd_interval *i = param_get_interval(p, n); return i->min; } return 0; } -static unsigned int param_get_max(struct snd_pcm_hw_params *p, int n) +static unsigned int param_get_max(const struct snd_pcm_hw_params *p, int n) { if (param_is_interval(n)) { - struct snd_interval *i = param_to_interval(p, n); + const struct snd_interval *i = param_get_interval(p, n); return i->max; } return 0; @@ -194,18 +199,49 @@ struct pcm { * @return The buffer size of the PCM. * @ingroup libtinyalsa-pcm */ -unsigned int pcm_get_buffer_size(struct pcm *pcm) +unsigned int pcm_get_buffer_size(const struct pcm *pcm) { return pcm->buffer_size; } +/** Gets the channel count of the PCM. + * @param pcm A PCM handle. + * @return The channel count of the PCM. + * @ingroup libtinyalsa-pcm + */ +unsigned int pcm_get_channels(const struct pcm *pcm) +{ + return pcm->config.channels; +} + +/** Gets the rate of the PCM. + * The rate is given in frames per second. + * @param pcm A PCM handle. + * @return The rate of the PCM. + * @ingroup libtinyalsa-pcm + */ +unsigned int pcm_get_rate(const struct pcm *pcm) +{ + return pcm->config.rate; +} + +/** Gets the format of the PCM. + * @param pcm A PCM handle. + * @return The format of the PCM. + * @ingroup libtinyalsa-pcm + */ +enum pcm_format pcm_get_format(const struct pcm *pcm) +{ + return pcm->config.format; +} + /** Gets the file descriptor of the PCM. * Useful for extending functionality of the PCM when needed. * @param pcm A PCM handle. * @return The file descriptor of the PCM. * @ingroup libtinyalsa-pcm */ -int pcm_get_file_descriptor(struct pcm *pcm) +int pcm_get_file_descriptor(const struct pcm *pcm) { return pcm->fd; } @@ -216,7 +252,7 @@ int pcm_get_file_descriptor(struct pcm *pcm) * @return The error message of the last error that occured. * @ingroup libtinyalsa-pcm */ -const char* pcm_get_error(struct pcm *pcm) +const char* pcm_get_error(const struct pcm *pcm) { return pcm->error; } @@ -224,7 +260,7 @@ const char* pcm_get_error(struct pcm *pcm) /** Gets the subdevice on which the pcm has been opened. * @param pcm A PCM handle. * @return The subdevice on which the pcm has been opened */ -unsigned int pcm_get_subdevice(struct pcm *pcm) +unsigned int pcm_get_subdevice(const struct pcm *pcm) { return pcm->subdevice; } @@ -306,7 +342,7 @@ unsigned int pcm_format_to_bits(enum pcm_format format) * @return The number of frames that may fit into @p bytes * @ingroup libtinyalsa-pcm */ -unsigned int pcm_bytes_to_frames(struct pcm *pcm, unsigned int bytes) +unsigned int pcm_bytes_to_frames(const struct pcm *pcm, unsigned int bytes) { return bytes / (pcm->config.channels * (pcm_format_to_bits(pcm->config.format) >> 3)); @@ -318,7 +354,7 @@ unsigned int pcm_bytes_to_frames(struct pcm *pcm, unsigned int bytes) * @return The bytes occupied by @p frames. * @ingroup libtinyalsa-pcm */ -unsigned int pcm_frames_to_bytes(struct pcm *pcm, unsigned int frames) +unsigned int pcm_frames_to_bytes(const struct pcm *pcm, unsigned int frames) { return frames * pcm->config.channels * (pcm_format_to_bits(pcm->config.format) >> 3); @@ -486,11 +522,11 @@ int pcm_get_htimestamp(struct pcm *pcm, unsigned int *avail, * This function is not valid for PCMs opened with the @ref PCM_MMAP flag. * @param pcm A PCM handle. * @param data The audio sample array - * @param count The number of bytes occupied by the sample array. - * @return On success, this function returns zero; otherwise, a negative number. + * @param frame_count The number of frames occupied by the sample array. + * @return On success, this function returns the number of frames written; otherwise, a negative number. * @ingroup libtinyalsa-pcm */ -int pcm_write(struct pcm *pcm, const void *data, unsigned int count) +int pcm_writei(struct pcm *pcm, const void *data, unsigned int frame_count) { struct snd_xferi x; @@ -498,8 +534,7 @@ int pcm_write(struct pcm *pcm, const void *data, unsigned int count) return -EINVAL; x.buf = (void*)data; - x.frames = count / (pcm->config.channels * - pcm_format_to_bits(pcm->config.format) / 8); + x.frames = frame_count; x.result = 0; for (;;) { if (!pcm->running) { @@ -525,7 +560,7 @@ int pcm_write(struct pcm *pcm, const void *data, unsigned int count) } return oops(pcm, errno, "cannot write stream data"); } - return 0; + return x.result; } } @@ -535,11 +570,11 @@ int pcm_write(struct pcm *pcm, const void *data, unsigned int count) * This function is not valid for PCMs opened with the @ref PCM_MMAP flag. * @param pcm A PCM handle. * @param data The audio sample array - * @param count The number of bytes occupied by the sample array. - * @return On success, this function returns zero; otherwise, a negative number. + * @param frame_count The number of frames occupied by the sample array. + * @return On success, this function returns the number of frames written; otherwise, a negative number. * @ingroup libtinyalsa-pcm */ -int pcm_read(struct pcm *pcm, void *data, unsigned int count) +int pcm_readi(struct pcm *pcm, void *data, unsigned int frame_count) { struct snd_xferi x; @@ -547,8 +582,7 @@ int pcm_read(struct pcm *pcm, void *data, unsigned int count) return -EINVAL; x.buf = data; - x.frames = count / (pcm->config.channels * - pcm_format_to_bits(pcm->config.format) / 8); + x.frames = frame_count; x.result = 0; for (;;) { if (!pcm->running) { @@ -567,8 +601,48 @@ int pcm_read(struct pcm *pcm, void *data, unsigned int count) } return oops(pcm, errno, "cannot read stream data"); } - return 0; + return x.result; + } +} + +/** Writes audio samples to PCM. + * If the PCM has not been started, it is started in this function. + * This function is only valid for PCMs opened with the @ref PCM_OUT flag. + * This function is not valid for PCMs opened with the @ref PCM_MMAP flag. + * @param pcm A PCM handle. + * @param data The audio sample array + * @param count The number of bytes occupied by the sample array. + * @return On success, this function returns zero; otherwise, a negative number. + * @deprecated + * @ingroup libtinyalsa-pcm + */ +int pcm_write(struct pcm *pcm, const void *data, unsigned int count) +{ + int ret = pcm_writei(pcm, data, pcm_bytes_to_frames(pcm, count)); + if (ret < 0){ + return ret; } + return 0; +} + +/** Reads audio samples from PCM. + * If the PCM has not been started, it is started in this function. + * This function is only valid for PCMs opened with the @ref PCM_IN flag. + * This function is not valid for PCMs opened with the @ref PCM_MMAP flag. + * @param pcm A PCM handle. + * @param data The audio sample array + * @param count The number of bytes occupied by the sample array. + * @return On success, this function returns zero; otherwise, a negative number. + * @deprecated + * @ingroup libtinyalsa-pcm + */ +int pcm_read(struct pcm *pcm, void *data, unsigned int count) +{ + int ret = pcm_readi(pcm, data, pcm_bytes_to_frames(pcm, count)); + if (ret < 0) { + return ret; + } + return 0; } static struct pcm bad_pcm = { @@ -696,7 +770,7 @@ static int pcm_param_to_alsa(enum pcm_param param) * Otherwise, the mask associated with @p param is returned. * @ingroup libtinyalsa-pcm */ -struct pcm_mask *pcm_params_get_mask(struct pcm_params *pcm_params, +const struct pcm_mask *pcm_params_get_mask(const struct pcm_params *pcm_params, enum pcm_param param) { int p; @@ -710,7 +784,7 @@ struct pcm_mask *pcm_params_get_mask(struct pcm_params *pcm_params, return NULL; } - return (struct pcm_mask *)param_to_mask(params, p); + return (const struct pcm_mask *)param_to_mask(params, p); } /** Get the minimum of a specified PCM parameter. @@ -719,7 +793,7 @@ struct pcm_mask *pcm_params_get_mask(struct pcm_params *pcm_params, * @returns On success, the parameter minimum. * On failure, zero. */ -unsigned int pcm_params_get_min(struct pcm_params *pcm_params, +unsigned int pcm_params_get_min(const struct pcm_params *pcm_params, enum pcm_param param) { struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; @@ -741,10 +815,10 @@ unsigned int pcm_params_get_min(struct pcm_params *pcm_params, * @returns On success, the parameter maximum. * On failure, zero. */ -unsigned int pcm_params_get_max(struct pcm_params *pcm_params, +unsigned int pcm_params_get_max(const struct pcm_params *pcm_params, enum pcm_param param) { - struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; + const struct snd_pcm_hw_params *params = (const struct snd_pcm_hw_params *)pcm_params; int p; if (!params) @@ -803,7 +877,7 @@ int pcm_close(struct pcm *pcm) * @ingroup libtinyalsa-pcm */ struct pcm *pcm_open(unsigned int card, unsigned int device, - unsigned int flags, struct pcm_config *config) + unsigned int flags, const struct pcm_config *config) { struct pcm *pcm; struct snd_pcm_info info; @@ -818,14 +892,14 @@ struct pcm *pcm_open(unsigned int card, unsigned int device, if (config == NULL) { config = &pcm->config; - config->channels = 2; - config->rate = 48000; - config->period_size = 1024; - config->period_count = 4; - config->format = PCM_FORMAT_S16_LE; - config->start_threshold = config->period_count * config->period_size; - config->stop_threshold = config->period_count * config->period_size; - config->silence_threshold = 0; + pcm->config.channels = 2; + pcm->config.rate = 48000; + pcm->config.period_size = 1024; + pcm->config.period_count = 4; + pcm->config.format = PCM_FORMAT_S16_LE; + pcm->config.start_threshold = config->period_count * config->period_size; + pcm->config.stop_threshold = config->period_count * config->period_size; + pcm->config.silence_threshold = 0; } else { pcm->config = *config; } @@ -885,8 +959,8 @@ struct pcm *pcm_open(unsigned int card, unsigned int device, } /* get our refined hw_params */ - config->period_size = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE); - config->period_count = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS); + pcm->config.period_size = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE); + pcm->config.period_count = param_get_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS); pcm->buffer_size = config->period_count * config->period_size; if (flags & PCM_MMAP) { @@ -974,7 +1048,7 @@ fail_close: * Otherwise, the function returns one. * @ingroup libtinyalsa-pcm */ -int pcm_is_ready(struct pcm *pcm) +int pcm_is_ready(const struct pcm *pcm) { return pcm->fd >= 0; } |