Add status and position functions to AudioPlayMemory

play_memory.cpp

 	prior = 0;
 	format = *data++;
 	next = data;
+	beginning = data;
 	length = format & 0xFFFFFF;
 	playing = format >> 24;
 }
 }
 
 
+#define B2M_88200 (uint32_t)((double)4294967296000.0 / AUDIO_SAMPLE_RATE_EXACT / 2.0)
+#define B2M_44100 (uint32_t)((double)4294967296000.0 / AUDIO_SAMPLE_RATE_EXACT) // 97352592
+#define B2M_22050 (uint32_t)((double)4294967296000.0 / AUDIO_SAMPLE_RATE_EXACT * 2.0)
+#define B2M_11025 (uint32_t)((double)4294967296000.0 / AUDIO_SAMPLE_RATE_EXACT * 4.0)
+
+
+uint32_t AudioPlayMemory::positionMillis(void)
+{
+	uint8_t p;
+	const uint8_t *n, *b;
+	uint32_t b2m;
+
+	__disable_irq();
+	p = playing;
+	n = (const uint8_t *)next;
+	b = (const uint8_t *)beginning;
+	__enable_irq();
+	switch (p) {
+	  case 0x81: // 16 bit PCM, 44100 Hz
+		b2m = B2M_88200;  break;
+	  case 0x01: // u-law encoded, 44100 Hz
+	  case 0x82: // 16 bits PCM, 22050 Hz
+		b2m = B2M_44100;  break;
+	  case 0x02: // u-law encoded, 22050 Hz
+	  case 0x83: // 16 bit PCM, 11025 Hz
+		b2m = B2M_22050;  break;
+	  case 0x03: // u-law encoded, 11025 Hz
+		b2m = B2M_11025;  break;
+	  default:
+		return 0;
+	}
+	if (p == 0) return 0;
+	return ((uint64_t)(n - b) * b2m) >> 32;
+}
+
+uint32_t AudioPlayMemory::lengthMillis(void)
+{
+	uint8_t p;
+	const uint32_t *b;
+	uint32_t b2m;
+
+	__disable_irq();
+	p = playing;
+	b = (const uint32_t *)beginning;
+	__enable_irq();
+	switch (p) {
+	  case 0x81: // 16 bit PCM, 44100 Hz
+	  case 0x01: // u-law encoded, 44100 Hz
+		b2m = B2M_44100;  break;
+	  case 0x82: // 16 bits PCM, 22050 Hz
+	  case 0x02: // u-law encoded, 22050 Hz
+		b2m = B2M_22050;  break;
+	  case 0x83: // 16 bit PCM, 11025 Hz
+	  case 0x03: // u-law encoded, 11025 Hz
+		b2m = B2M_11025;  break;
+	  default:
+		return 0;
+	}
+	return ((uint64_t)(*(b - 1) & 0xFFFFFF) * b2m) >> 32;
+}
+
 

play_memory.h

 	AudioPlayMemory(void) : AudioStream(0, NULL), playing(0) { }
 	void play(const unsigned int *data);
 	void stop(void);
+	bool isPlaying(void) { return playing; }
+	uint32_t positionMillis(void);
+	uint32_t lengthMillis(void);
 	virtual void update(void);
 private:
 	const unsigned int *next;
+	const unsigned int *beginning;
 	uint32_t length;
 	int16_t prior;
 	volatile uint8_t playing;