Initial MP3 refactor

Using mpg123_outblock doesn't work correctly. Also assigning variables
to different types.

Signed-off-by: Mahyar Koshkouei <deltabeard@users.noreply.github.com>

source/mp3.c

@@ -6,6 +6,108 @@
 #include "all.h"
 #include "mp3.h"
 
+static int				buffSize = 64 * 1024;
+static mpg123_handle	*mh = NULL;
+static uint32_t			rate = 0;
+static uint8_t			channels = 0;
+
+/**
+ * Set decoder parameters for MP3.
+ *
+ * \param	decoder Structure to store parameters.
+ */
+void setMp3(struct decoder_fn* decoder)
+{
+	decoder->init = &initMp3;
+	decoder->rate = &rateMp3;
+	decoder->channels = &channelMp3;
+	decoder->buffSize = buffSize;
+	decoder->decode = &decodeMp3;
+	decoder->exit = &exitMp3;
+}
+
+/**
+ * Initialise MP3 decoder.
+ *
+ * \param	file	Location of MP3 file to play.
+ * \return			0 on success, else failure.
+ */
+int initMp3(const char* file)
+{
+	int err = 0;
+	int encoding = 0;
+
+	if((err = mpg123_init()) != MPG123_OK)
+		return err;
+
+	if((mh = mpg123_new(NULL, &err)) == NULL)
+	{
+		//printf("Error: %s\n", mpg123_plain_strerror(err));
+		return err;
+	}
+
+	if(mpg123_open(mh, file) != MPG123_OK ||
+			mpg123_getformat(mh, &rate, &channels, &encoding) != MPG123_OK)
+	{
+		//printf("Trouble with mpg123: %s\n", mpg123_strerror(mh));
+		return -1;
+	}
+
+	/* Ensure that this output format will not change
+	   (it might, when we allow it). */
+	mpg123_format_none(mh);
+	mpg123_format(mh, rate, channels, encoding);
+
+	/* Buffer could be almost any size here, mpg123_outblock() is just some
+	   recommendation. The size should be a multiple of the PCM frame size. */
+	//buffSize = mpg123_outblock(mh) * 16;
+
+	return 0;
+}
+
+/**
+ * Get sampling rate of MP3 file.
+ *
+ * \return	Sampling rate.
+ */
+uint32_t rateMp3(void)
+{
+	return rate;
+}
+
+/**
+ * Get number of channels of MP3 file.
+ *
+ * \return	Number of channels for opened file.
+ */
+uint8_t channelMp3(void)
+{
+	return channels;
+}
+
+/**
+ * Decode part of open MP3 file.
+ *
+ * \param buffer	Decoded output.
+ * \return			Samples read for each channel.
+ */
+uint64_t decodeMp3(void* buffer)
+{
+	int done = 0;
+	mpg123_read(mh, buffer, buffSize, &done);
+	return done / (sizeof(int16_t));
+}
+
+/**
+ * Free MP3 decoder.
+ */
+void exitMp3(void)
+{
+	mpg123_close(mh);
+	mpg123_delete(mh);
+	mpg123_exit();
+}
+
 int playMp3(const char* in)
 {
 	int				err = 0;

source/mp3.h

@@ -1,3 +1,45 @@
 #include <mpg123.h>
 
+/**
+ * Set decoder parameters for MP3.
+ *
+ * \param	decoder Structure to store parameters.
+ */
+void setMp3(struct decoder_fn* decoder);
+
+/**
+ * Initialise MP3 decoder.
+ *
+ * \param	file	Location of MP3 file to play.
+ * \return			0 on success, else failure.
+ */
+int initMp3(const char* file);
+
+/**
+ * Get sampling rate of MP3 file.
+ *
+ * \return	Sampling rate.
+ */
+uint32_t rateMp3(void);
+
+/**
+ * Get number of channels of MP3 file.
+ *
+ * \return	Number of channels for opened file.
+ */
+uint8_t channelMp3(void);
+
+/**
+ * Decode part of open MP3 file.
+ *
+ * \param buffer	Decoded output.
+ * \return			Samples read for each channel.
+ */
+uint64_t decodeMp3(void* buffer);
+
+/**
+ * Free MP3 decoder.
+ */
+void exitMp3(void);
+
 int playMp3(const char* in);

source/playback.c

@@ -36,8 +36,10 @@ int playFile(const char* file)
 			break;
 
 		case FILE_TYPE_MP3:
-			playMp3(file);
-			return 0;
+			setMp3(&decoder);
+			break;
+			//playMp3(file);
+			//return 0;
 
 		default:
 			printf("Unsupported File type.\n");