Allow to specify pre-allocated buffer in audicore.WaveFile

It lets us re-use the same buffer for playing multiple files.
This also allows us to control the size of the buffer. Half of the
buffer will be used for the fist, and half for the second internal
buffer.

3 files changed, 39 insertions, 18 deletions

diff --git a/shared-bindings/audiocore/WaveFile.c b/shared-bindings/audiocore/WaveFile.c
index 4c1993b7c..7398353b0 100644
--- a/shared-bindings/audiocore/WaveFile.c
+++ b/shared-bindings/audiocore/WaveFile.c
@@ -39,13 +39,15 @@
 //| ========================================================
 //|
 //| A .wav file prepped for audio playback. Only mono and stereo files are supported. Samples must
-//| be 8 bit unsigned or 16 bit signed.
+//| be 8 bit unsigned or 16 bit signed. If a buffer is provided, it will be used instead of allocating
+//| an internal buffer.
 //|
-//| .. class:: WaveFile(file)
+//| .. class:: WaveFile(file[, buffer])
 //|
 //|   Load a .wav file for playback with `audioio.AudioOut` or `audiobusio.I2SOut`.
 //|
 //|   :param typing.BinaryIO file: Already opened wave file
+//|   :param bytearray buffer: Optional pre-allocated buffer
 //|
 //|   Playing a wave file from flash::
 //|
@@ -68,15 +70,23 @@
 //|     print("stopped")
 //|
 STATIC mp_obj_t audioio_wavefile_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
-    mp_arg_check_num(n_args, kw_args, 1, 1, false);
+    mp_arg_check_num(n_args, kw_args, 1, 2, false);
 
     audioio_wavefile_obj_t *self = m_new_obj(audioio_wavefile_obj_t);
     self->base.type = &audioio_wavefile_type;
-    if (MP_OBJ_IS_TYPE(args[0], &mp_type_fileio)) {
-        common_hal_audioio_wavefile_construct(self, MP_OBJ_TO_PTR(args[0]));
-    } else {
+    if (!MP_OBJ_IS_TYPE(args[0], &mp_type_fileio)) {
         mp_raise_TypeError(translate("file must be a file opened in byte mode"));
     }
+    uint8_t *buffer = NULL;
+    size_t buffer_size = 0;
+    if (n_args >= 2) {
+        mp_buffer_info_t bufinfo;
+        mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_WRITE);
+        buffer = bufinfo.buf;
+        buffer_size = bufinfo.len;
+    }
+    common_hal_audioio_wavefile_construct(self, MP_OBJ_TO_PTR(args[0]),
+                                          buffer, buffer_size);
 
     return MP_OBJ_FROM_PTR(self);
 }
diff --git a/shared-bindings/audiocore/WaveFile.h b/shared-bindings/audiocore/WaveFile.h
index d2572318b..f4a172319 100644
--- a/shared-bindings/audiocore/WaveFile.h
+++ b/shared-bindings/audiocore/WaveFile.h
@@ -35,7 +35,7 @@
 extern const mp_obj_type_t audioio_wavefile_type;
 
 void common_hal_audioio_wavefile_construct(audioio_wavefile_obj_t* self,
-    pyb_file_obj_t* file);
+    pyb_file_obj_t* file, uint8_t *buffer, size_t buffer_size);
 
 void common_hal_audioio_wavefile_deinit(audioio_wavefile_obj_t* self);
 bool common_hal_audioio_wavefile_deinited(audioio_wavefile_obj_t* self);
diff --git a/shared-module/audiocore/WaveFile.c b/shared-module/audiocore/WaveFile.c
index 810d9c33b..df5d4b61d 100644
--- a/shared-module/audiocore/WaveFile.c
+++ b/shared-module/audiocore/WaveFile.c
@@ -46,7 +46,9 @@ struct wave_format_chunk {
 };
 
 void common_hal_audioio_wavefile_construct(audioio_wavefile_obj_t* self,
-                                           pyb_file_obj_t* file) {
+                                           pyb_file_obj_t* file,
+                                           uint8_t *buffer,
+                                           size_t buffer_size) {
     // Load the wave
     self->file = file;
     uint8_t chunk_header[16];
@@ -84,7 +86,6 @@ void common_hal_audioio_wavefile_construct(audioio_wavefile_obj_t* self,
     }
     // Get the sample_rate
     self->sample_rate = format.sample_rate;
-    self->len = 256;
     self->channel_count = format.num_channels;
     self->bits_per_sample = format.bits_per_sample;
 
@@ -111,21 +112,31 @@ void common_hal_audioio_wavefile_construct(audioio_wavefile_obj_t* self,
 
     // Try to allocate two buffers, one will be loaded from file and the other
     // DMAed to DAC.
-    self->buffer = m_malloc(self->len, false);
-    if (self->buffer == NULL) {
-        common_hal_audioio_wavefile_deinit(self);
-        mp_raise_msg(&mp_type_MemoryError, translate("Couldn't allocate first buffer"));
-    }
+    if (buffer_size) {
+        self->len = buffer_size / 2;
+        self->buffer = buffer;
+        self->second_buffer = buffer + self->len;
+    } else {
+        self->len = 256;
+        self->buffer = m_malloc(self->len, false);
+        if (self->buffer == NULL) {
+            common_hal_audioio_wavefile_deinit(self);
+            mp_raise_msg(&mp_type_MemoryError,
+                         translate("Couldn't allocate first buffer"));
+        }
 
-    self->second_buffer = m_malloc(self->len, false);
-    if (self->second_buffer == NULL) {
-        common_hal_audioio_wavefile_deinit(self);
-        mp_raise_msg(&mp_type_MemoryError, translate("Couldn't allocate second buffer"));
+        self->second_buffer = m_malloc(self->len, false);
+        if (self->second_buffer == NULL) {
+            common_hal_audioio_wavefile_deinit(self);
+            mp_raise_msg(&mp_type_MemoryError,
+                         translate("Couldn't allocate second buffer"));
+        }
     }
 }
 
 void common_hal_audioio_wavefile_deinit(audioio_wavefile_obj_t* self) {
     self->buffer = NULL;
+    self->second_buffer = NULL;
 }
 
 bool common_hal_audioio_wavefile_deinited(audioio_wavefile_obj_t* self) {