Merge branch 'const-correctness' into develop

Added const specifiers to all applicable functions in the PCM API.

3 files changed, 44 insertions, 39 deletions

diff --git a/include/tinyalsa/pcm.h b/include/tinyalsa/pcm.h
index 3d9dfaa..a6c95ce 100644
--- a/include/tinyalsa/pcm.h
+++ b/include/tinyalsa/pcm.h
@@ -223,38 +223,38 @@ struct pcm_params *pcm_params_get(unsigned int card, unsigned int device,
 
 void pcm_params_free(struct pcm_params *pcm_params);
 
-struct pcm_mask *pcm_params_get_mask(struct pcm_params *pcm_params, enum pcm_param param);
+const struct pcm_mask *pcm_params_get_mask(const struct pcm_params *pcm_params, enum pcm_param param);
 
-unsigned int pcm_params_get_min(struct pcm_params *pcm_params, enum pcm_param param);
+unsigned int pcm_params_get_min(const struct pcm_params *pcm_params, enum pcm_param param);
 
-unsigned int pcm_params_get_max(struct pcm_params *pcm_params, enum pcm_param param);
+unsigned int pcm_params_get_max(const struct pcm_params *pcm_params, enum pcm_param param);
 
 struct pcm;
 
 struct pcm *pcm_open(unsigned int card,
                      unsigned int device,
                      unsigned int flags,
-                     struct pcm_config *config);
+                     const struct pcm_config *config);
 
 int pcm_close(struct pcm *pcm);
 	
-int pcm_is_ready(struct pcm *pcm);
+int pcm_is_ready(const struct pcm *pcm);
 
-int pcm_get_file_descriptor(struct pcm *pcm);
+int pcm_get_file_descriptor(const struct pcm *pcm);
 
-const char *pcm_get_error(struct pcm *pcm);
+const char *pcm_get_error(const struct pcm *pcm);
 
 unsigned int pcm_format_to_bits(enum pcm_format format);
 
-unsigned int pcm_get_buffer_size(struct pcm *pcm);
+unsigned int pcm_get_buffer_size(const struct pcm *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);
 
-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);
 
 int pcm_get_htimestamp(struct pcm *pcm, unsigned int *avail, struct timespec *tstamp);
 
-unsigned int pcm_get_subdevice(struct pcm *pcm);
+unsigned int pcm_get_subdevice(const struct pcm *pcm);
 
 int pcm_write(struct pcm *pcm, const void *data, unsigned int count);
 
diff --git a/src/pcm.c b/src/pcm.c
index 1ce1a54..540fd72 100644
--- a/src/pcm.c
+++ b/src/pcm.c
@@ -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;
@@ -194,7 +199,7 @@ 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;
 }
@@ -205,7 +210,7 @@ unsigned int pcm_get_buffer_size(struct pcm *pcm)
  * @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 +221,7 @@ 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 +229,7 @@ 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 +311,7 @@ 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 +323,7 @@ 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);
@@ -696,7 +701,7 @@ 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 +715,7 @@ 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 +724,7 @@ 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 +746,10 @@ 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 +808,7 @@ 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 +823,14 @@ 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 +890,8 @@ struct pcm *pcm_open(unsigned int card, unsigned int device,
     }
 
     /* get our refined hw_params */
-    config->period_size = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
-    config->period_count = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIODS);
+    pcm->config.period_size = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
+    pcm->config.period_count = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIODS);
     pcm->buffer_size = config->period_count * config->period_size;
 
     if (flags & PCM_MMAP) {
@@ -974,7 +979,7 @@ 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;
 }
diff --git a/utils/tinypcminfo.c b/utils/tinypcminfo.c
index 5b8db1f..0dd381d 100644
--- a/utils/tinypcminfo.c
+++ b/utils/tinypcminfo.c
@@ -129,7 +129,7 @@ int main(int argc, char **argv)
 
     for (i = 0; i < 2; i++) {
         struct pcm_params *params;
-        struct pcm_mask *m;
+        const struct pcm_mask *m;
         unsigned int min;
         unsigned int max;