Merge branch 'develop'

This merges all the changes for the 1.1.0 release to the master branch.

11 files changed, 252 insertions, 91 deletions

diff --git a/debian/changelog b/debian/changelog
index 851ac70..8a47e9a 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,17 @@
+tinyalsa (1.1.0) xenial; urgency=medium
+
+  * Finished most of the PCM and mixer API documentation
+  * Added const specifiers where necessary
+  * Added pcm_readi() and pcm_writei()
+  * Deprecated pcm_read() and pcm_write()
+  * Added mixer_get_num_ctls_by_name()
+  * Added pcm_get_channels(), pcm_get_rate() and pcm_get_format()
+  * Made libtinyalsa.so.x a symbol link, using libtinyalsa.so.x.y.z as library name
+  * Added long option names in tinyplay
+  * Using amixer-style interface for tinymix
+
+ -- Taylor Holberton <taylorcholberton@gmail.com>  Thu, 01 Dec 2016 21:38:12 -0800
+
 tinyalsa (1.0.2) xenial; urgency=medium
 
   * Removed install of libtinyalsa.so in package libtinyalsa
diff --git a/doxygen/Doxyfile b/doxygen/Doxyfile
index 6a3a2d2..1c18b30 100644
--- a/doxygen/Doxyfile
+++ b/doxygen/Doxyfile
@@ -38,7 +38,7 @@ PROJECT_NAME           = "TinyALSA"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 1.0.0
+PROJECT_NUMBER         = 1.1.0
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/include/tinyalsa/mixer.h b/include/tinyalsa/mixer.h
index 4de6133..f743f6e 100644
--- a/include/tinyalsa/mixer.h
+++ b/include/tinyalsa/mixer.h
@@ -69,9 +69,13 @@ struct mixer *mixer_open(unsigned int card);
 
 void mixer_close(struct mixer *mixer);
 
-const char *mixer_get_name(struct mixer *mixer);
+const char *mixer_get_name(const struct mixer *mixer);
 
-unsigned int mixer_get_num_ctls(struct mixer *mixer);
+unsigned int mixer_get_num_ctls(const struct mixer *mixer);
+
+unsigned int mixer_get_num_ctls_by_name(const struct mixer *mixer, const char *name);
+
+const struct mixer_ctl *mixer_get_ctl_const(const struct mixer *mixer, unsigned int id);
 
 struct mixer_ctl *mixer_get_ctl(struct mixer *mixer, unsigned int id);
 
@@ -81,17 +85,17 @@ struct mixer_ctl *mixer_get_ctl_by_name_and_index(struct mixer *mixer,
                                                   const char *name,
                                                   unsigned int index);
 
-unsigned int mixer_ctl_get_id(struct mixer_ctl *ctl);
+unsigned int mixer_ctl_get_id(const struct mixer_ctl *ctl);
 
-const char *mixer_ctl_get_name(struct mixer_ctl *ctl);
+const char *mixer_ctl_get_name(const struct mixer_ctl *ctl);
 
-enum mixer_ctl_type mixer_ctl_get_type(struct mixer_ctl *ctl);
+enum mixer_ctl_type mixer_ctl_get_type(const struct mixer_ctl *ctl);
 
-const char *mixer_ctl_get_type_string(struct mixer_ctl *ctl);
+const char *mixer_ctl_get_type_string(const struct mixer_ctl *ctl);
 
-unsigned int mixer_ctl_get_num_values(struct mixer_ctl *ctl);
+unsigned int mixer_ctl_get_num_values(const struct mixer_ctl *ctl);
 
-unsigned int mixer_ctl_get_num_enums(struct mixer_ctl *ctl);
+unsigned int mixer_ctl_get_num_enums(const struct mixer_ctl *ctl);
 
 const char *mixer_ctl_get_enum_string(struct mixer_ctl *ctl, unsigned int enum_id);
 
@@ -102,13 +106,13 @@ const char *mixer_ctl_get_enum_string(struct mixer_ctl *ctl, unsigned int enum_i
 void mixer_ctl_update(struct mixer_ctl *ctl);
 
 /* Set and get mixer controls */
-int mixer_ctl_get_percent(struct mixer_ctl *ctl, unsigned int id);
+int mixer_ctl_get_percent(const struct mixer_ctl *ctl, unsigned int id);
 
 int mixer_ctl_set_percent(struct mixer_ctl *ctl, unsigned int id, int percent);
 
-int mixer_ctl_get_value(struct mixer_ctl *ctl, unsigned int id);
+int mixer_ctl_get_value(const struct mixer_ctl *ctl, unsigned int id);
 
-int mixer_ctl_get_array(struct mixer_ctl *ctl, void *array, size_t count);
+int mixer_ctl_get_array(const struct mixer_ctl *ctl, void *array, size_t count);
 
 int mixer_ctl_set_value(struct mixer_ctl *ctl, unsigned int id, int value);
 
@@ -117,9 +121,9 @@ int mixer_ctl_set_array(struct mixer_ctl *ctl, const void *array, size_t count);
 int mixer_ctl_set_enum_by_string(struct mixer_ctl *ctl, const char *string);
 
 /* Determe range of integer mixer controls */
-int mixer_ctl_get_range_min(struct mixer_ctl *ctl);
+int mixer_ctl_get_range_min(const struct mixer_ctl *ctl);
 
-int mixer_ctl_get_range_max(struct mixer_ctl *ctl);
+int mixer_ctl_get_range_max(const struct mixer_ctl *ctl);
 
 #if defined(__cplusplus)
 }  /* extern "C" */
diff --git a/include/tinyalsa/pcm.h b/include/tinyalsa/pcm.h
index 3d9dfaa..1d84eed 100644
--- a/include/tinyalsa/pcm.h
+++ b/include/tinyalsa/pcm.h
@@ -223,43 +223,63 @@ 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);
+unsigned int pcm_get_channels(const struct pcm *pcm);
 
-const char *pcm_get_error(struct pcm *pcm);
+unsigned int pcm_get_rate(const struct pcm *pcm);
+
+enum pcm_format pcm_get_format(const struct pcm *pcm);
+
+int pcm_get_file_descriptor(const 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_writei(struct pcm *pcm, const void *data, unsigned int frame_count);
+
+int pcm_readi(struct pcm *pcm, void *data, unsigned int frame_count);
+
+#ifdef __GNUC__
+
+int pcm_write(struct pcm *pcm, const void *data, unsigned int count) __attribute((deprecated));
+
+int pcm_read(struct pcm *pcm, void *data, unsigned int count) __attribute((deprecated));
+
+#else
 
 int pcm_write(struct pcm *pcm, const void *data, unsigned int count);
 
 int pcm_read(struct pcm *pcm, void *data, unsigned int count);
 
+#endif
+
 int pcm_mmap_write(struct pcm *pcm, const void *data, unsigned int count);
 
 int pcm_mmap_read(struct pcm *pcm, void *data, unsigned int count);
diff --git a/include/tinyalsa/version.h b/include/tinyalsa/version.h
index b92e030..5d71840 100644
--- a/include/tinyalsa/version.h
+++ b/include/tinyalsa/version.h
@@ -31,13 +31,13 @@
 
 #define TINYALSA_VERSION_MAJOR 1
 
-#define TINYALSA_VERSION_MINOR 0
+#define TINYALSA_VERSION_MINOR 1
 
-#define TINYALSA_VERSION_PATCH 3
+#define TINYALSA_VERSION_PATCH 0
 
-#define TINYALSA_VERSION 0x010003UL
+#define TINYALSA_VERSION 0x010100UL
 
-#define TINYALSA_VERSION_STRING "1.0.3"
+#define TINYALSA_VERSION_STRING "1.1.0"
 
 #endif /* TINYALSA_VERSION_H */
 
diff --git a/src/Makefile b/src/Makefile
index da19c54..cde8267 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -19,7 +19,7 @@ VPATH = ../include/tinyalsa
 OBJECTS = mixer.o pcm.o
 
 .PHONY: all
-all: libtinyalsa.a libtinyalsa.so.1
+all: libtinyalsa.a libtinyalsa.so
 
 pcm.o: pcm.c pcm.h
 
@@ -28,19 +28,28 @@ mixer.o: mixer.c mixer.h
 libtinyalsa.a: $(OBJECTS)
 	$(AR) $(ARFLAGS) $@ $^
 
-libtinyalsa.so.1: $(OBJECTS)
-	$(LD) $(LDFLAGS) -shared $^ -o $@
+libtinyalsa.so: libtinyalsa.so.1
+	ln -sf $< $@
+
+libtinyalsa.so.1: libtinyalsa.so.1.1.0
+	ln -sf $< $@
+
+libtinyalsa.so.1.1.0: $(OBJECTS)
+	$(LD) $(LDFLAGS) -shared -Wl,-soname,libtinyalsa.so.1 $^ -o $@
 
 .PHONY: clean
 clean:
 	rm -f libtinyalsa.a
+	rm -f libtinyalsa.so
 	rm -f libtinyalsa.so.1
+	rm -f libtinyalsa.so.1.1.0
 	rm -f $(OBJECTS)
 
 .PHONY: install
 install: libtinyalsa.a libtinyalsa.so.1
 	install -d $(DESTDIR)$(LIBDIR)/
-	ln -sf libtinyalsa.so.1 $(DESTDIR)$(LIBDIR)/libtinyalsa.so
 	install libtinyalsa.a $(DESTDIR)$(LIBDIR)/
-	install libtinyalsa.so.1 $(DESTDIR)$(LIBDIR)/
+	install libtinyalsa.so.1.1.0 $(DESTDIR)$(LIBDIR)/
+	ln -sf libtinyalsa.so.1.1.0 $(DESTDIR)$(LIBDIR)/libtinyalsa.so.1
+	ln -sf libtinyalsa.so.1 $(DESTDIR)$(LIBDIR)/libtinyalsa.so
 
diff --git a/src/mixer.c b/src/mixer.c
index 0fe9c99..9e661c5 100644
--- a/src/mixer.c
+++ b/src/mixer.c
@@ -176,7 +176,7 @@ fail:
  * @returns The name of the mixer's card.
  * @ingroup libtinyalsa-mixer
  */
-const char *mixer_get_name(struct mixer *mixer)
+const char *mixer_get_name(const struct mixer *mixer)
 {
     return (const char *)mixer->card_info.name;
 }
@@ -186,7 +186,7 @@ const char *mixer_get_name(struct mixer *mixer)
  * @returns The number of mixer controls for the given mixer.
  * @ingroup libtinyalsa-mixer
  */
-unsigned int mixer_get_num_ctls(struct mixer *mixer)
+unsigned int mixer_get_num_ctls(const struct mixer *mixer)
 {
     if (!mixer)
         return 0;
@@ -194,7 +194,47 @@ unsigned int mixer_get_num_ctls(struct mixer *mixer)
     return mixer->count;
 }
 
+/** Gets the number of mixer controls, that go by a specified name, for a given mixer.
+ * @param mixer An initialized mixer handle.
+ * @param name The name of the mixer control
+ * @returns The number of mixer controls, specified by @p name, for the given mixer.
+ * @ingroup libtinyalsa-mixer
+ */
+unsigned int mixer_get_num_ctls_by_name(const struct mixer *mixer, const char *name)
+{
+    unsigned int n;
+    unsigned int count = 0;
+    struct mixer_ctl *ctl;
+
+    if (!mixer)
+        return 0;
+
+    ctl = mixer->ctl;
+
+    for (n = 0; n < mixer->count; n++)
+        if (!strcmp(name, (char*) ctl[n].info.id.name))
+            count++;
+
+    return count;
+}
+
+/** Gets a mixer control handle, by the mixer control's id.
+ * For non-const access, see @ref mixer_get_ctl
+ * @param mixer An initialized mixer handle.
+ * @param id The control's id in the given mixer.
+ * @returns A handle to the mixer control.
+ * @ingroup libtinyalsa-mixer
+ */
+const struct mixer_ctl *mixer_get_ctl_const(const struct mixer *mixer, unsigned int id)
+{
+    if (mixer && (id < mixer->count))
+        return mixer->ctl + id;
+
+    return NULL;
+}
+
 /** Gets a mixer control handle, by the mixer control's id.
+ * For const access, see @ref mixer_get_ctl_const
  * @param mixer An initialized mixer handle.
  * @param id The control's id in the given mixer.
  * @returns A handle to the mixer control.
@@ -263,7 +303,7 @@ void mixer_ctl_update(struct mixer_ctl *ctl)
  *  On error, UINT_MAX is returned instead.
  * @ingroup libtinyalsa-mixer
  */
-unsigned int mixer_ctl_get_id(struct mixer_ctl *ctl)
+unsigned int mixer_ctl_get_id(const struct mixer_ctl *ctl)
 {
     if (!ctl)
         return UINT_MAX;
@@ -280,7 +320,7 @@ unsigned int mixer_ctl_get_id(struct mixer_ctl *ctl)
  *  On error, NULL.
  * @ingroup libtinyalsa-mixer
  */
-const char *mixer_ctl_get_name(struct mixer_ctl *ctl)
+const char *mixer_ctl_get_name(const struct mixer_ctl *ctl)
 {
     if (!ctl)
         return NULL;
@@ -294,7 +334,7 @@ const char *mixer_ctl_get_name(struct mixer_ctl *ctl)
  *  On failure, it returns @ref MIXER_CTL_TYPE_UNKNOWN
  * @ingroup libtinyalsa-mixer
  */
-enum mixer_ctl_type mixer_ctl_get_type(struct mixer_ctl *ctl)
+enum mixer_ctl_type mixer_ctl_get_type(const struct mixer_ctl *ctl)
 {
     if (!ctl)
         return MIXER_CTL_TYPE_UNKNOWN;
@@ -315,7 +355,7 @@ enum mixer_ctl_type mixer_ctl_get_type(struct mixer_ctl *ctl)
  * @returns On success, a string describing type of mixer control.
  * @ingroup libtinyalsa-mixer
  */
-const char *mixer_ctl_get_type_string(struct mixer_ctl *ctl)
+const char *mixer_ctl_get_type_string(const struct mixer_ctl *ctl)
 {
     if (!ctl)
         return "";
@@ -336,7 +376,7 @@ const char *mixer_ctl_get_type_string(struct mixer_ctl *ctl)
  * @returns The number of values in the mixer control
  * @ingroup libtinyalsa-mixer
  */
-unsigned int mixer_ctl_get_num_values(struct mixer_ctl *ctl)
+unsigned int mixer_ctl_get_num_values(const struct mixer_ctl *ctl)
 {
     if (!ctl)
         return 0;
@@ -344,7 +384,7 @@ unsigned int mixer_ctl_get_num_values(struct mixer_ctl *ctl)
     return ctl->info.count;
 }
 
-static int percent_to_int(struct snd_ctl_elem_info *ei, int percent)
+static int percent_to_int(const struct snd_ctl_elem_info *ei, int percent)
 {
     if ((percent > 100) || (percent < 0)) {
         return -EINVAL;
@@ -355,7 +395,7 @@ static int percent_to_int(struct snd_ctl_elem_info *ei, int percent)
     return ei->value.integer.min + (range * percent) / 100;
 }
 
-static int int_to_percent(struct snd_ctl_elem_info *ei, int value)
+static int int_to_percent(const struct snd_ctl_elem_info *ei, int value)
 {
     int range = (ei->value.integer.max - ei->value.integer.min);
 
@@ -372,7 +412,7 @@ static int int_to_percent(struct snd_ctl_elem_info *ei, int value)
  *  On failure, -EINVAL is returned.
  * @ingroup libtinyalsa-mixer
  */
-int mixer_ctl_get_percent(struct mixer_ctl *ctl, unsigned int id)
+int mixer_ctl_get_percent(const struct mixer_ctl *ctl, unsigned int id)
 {
     if (!ctl || (ctl->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER))
         return -EINVAL;
@@ -403,7 +443,7 @@ int mixer_ctl_set_percent(struct mixer_ctl *ctl, unsigned int id, int percent)
  *  On failure, -EINVAL is returned.
  * @ingroup libtinyalsa-mixer
  */
-int mixer_ctl_get_value(struct mixer_ctl *ctl, unsigned int id)
+int mixer_ctl_get_value(const struct mixer_ctl *ctl, unsigned int id)
 {
     struct snd_ctl_elem_value ev;
     int ret;
@@ -449,7 +489,7 @@ int mixer_ctl_get_value(struct mixer_ctl *ctl, unsigned int id)
  *  On failure, non-zero.
  * @ingroup libtinyalsa-mixer
  */
-int mixer_ctl_get_array(struct mixer_ctl *ctl, void *array, size_t count)
+int mixer_ctl_get_array(const struct mixer_ctl *ctl, void *array, size_t count)
 {
     struct snd_ctl_elem_value ev;
     int ret = 0;
@@ -634,7 +674,7 @@ int mixer_ctl_set_array(struct mixer_ctl *ctl, const void *array, size_t count)
  *  On failure, -EINVAL.
  * @ingroup libtinyalsa-mixer
  */
-int mixer_ctl_get_range_min(struct mixer_ctl *ctl)
+int mixer_ctl_get_range_min(const struct mixer_ctl *ctl)
 {
     if (!ctl || (ctl->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER))
         return -EINVAL;
@@ -650,7 +690,7 @@ int mixer_ctl_get_range_min(struct mixer_ctl *ctl)
  *  On failure, -EINVAL.
  * @ingroup libtinyalsa-mixer
  */
-int mixer_ctl_get_range_max(struct mixer_ctl *ctl)
+int mixer_ctl_get_range_max(const struct mixer_ctl *ctl)
 {
     if (!ctl || (ctl->info.type != SNDRV_CTL_ELEM_TYPE_INTEGER))
         return -EINVAL;
@@ -663,7 +703,7 @@ int mixer_ctl_get_range_max(struct mixer_ctl *ctl)
  * @returns The number of enumerated items in the control.
  * @ingroup libtinyalsa-mixer
  */
-unsigned int mixer_ctl_get_num_enums(struct mixer_ctl *ctl)
+unsigned int mixer_ctl_get_num_enums(const struct mixer_ctl *ctl)
 {
     if (!ctl)
         return 0;
diff --git a/src/pcm.c b/src/pcm.c
index 1ce1a54..f879fe7 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;
@@ -194,18 +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(&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 +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;
 }
diff --git a/utils/tinycap.c b/utils/tinycap.c
index 503b118..05c7180 100644
--- a/utils/tinycap.c
+++ b/utils/tinycap.c
@@ -244,7 +244,7 @@ unsigned int capture_sample(FILE *file, unsigned int card, unsigned int device,
            pcm_format_to_bits(format));
     }
 
-    while (capturing && !pcm_read(pcm, buffer, size)) {
+    while (capturing && (pcm_readi(pcm, buffer, size) < 0)) {
         if (capture_time > 0 &&
             ((bytes_read + size) > pcm_frames_to_bytes(pcm, capture_time * rate))) {
             size = pcm_frames_to_bytes(pcm, capture_time * rate) - bytes_read;
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;
 
diff --git a/utils/tinyplay.c b/utils/tinyplay.c
index db1b611..d0c1e36 100644
--- a/utils/tinyplay.c
+++ b/utils/tinyplay.c
@@ -409,7 +409,7 @@ int play_sample(struct ctx *ctx)
     do {
         num_read = fread(buffer, 1, size, ctx->file);
         if (num_read > 0) {
-            if (pcm_write(ctx->pcm, buffer, num_read)) {
+            if (pcm_writei(ctx->pcm, buffer, num_read) < 0) {
                 fprintf(stderr, "error playing sample\n");
                 break;
             }