1 files changed, 133 insertions, 0 deletions
diff --git a/servers/audio/audio_rb_resampler.h b/servers/audio/audio_rb_resampler.h
new file mode 100644
index 0000000000..3c686374f4
--- /dev/null
+++ b/servers/audio/audio_rb_resampler.h
@@ -0,0 +1,133 @@
+#ifndef AUDIO_RB_RESAMPLER_H
+#define AUDIO_RB_RESAMPLER_H
+
+#include "typedefs.h"
+#include "os/memory.h"
+
+struct AudioRBResampler {
+
+	uint32_t rb_bits;
+	uint32_t rb_len;
+	uint32_t rb_mask;
+	uint32_t read_buff_len;
+	uint32_t channels;
+	uint32_t src_mix_rate;
+	uint32_t target_mix_rate;
+
+	volatile int rb_read_pos;
+	volatile int rb_write_pos;
+
+	int32_t offset; //contains the fractional remainder of the resampler
+	enum {
+		MIX_FRAC_BITS=13,
+		MIX_FRAC_LEN=(1<<MIX_FRAC_BITS),
+		MIX_FRAC_MASK=MIX_FRAC_LEN-1,
+	};
+
+	int16_t *read_buf;
+	int16_t *rb;
+
+
+	template<int C>
+	uint32_t _resample(int32_t *p_dest,int p_todo,int32_t p_increment);
+
+
+public:
+
+	_FORCE_INLINE_ void flush() {
+		rb_read_pos=0;
+		rb_write_pos=0;
+	}
+
+	_FORCE_INLINE_ bool is_ready() const{
+		return rb!=NULL;
+	}
+
+
+	_FORCE_INLINE_ int get_total() const {
+
+		return rb_len-1;
+	}
+
+	_FORCE_INLINE_ int get_todo() const { //return amount of frames to mix
+
+		int todo;
+		int read_pos_cache=rb_read_pos;
+
+		if (read_pos_cache==rb_write_pos) {
+			todo=rb_len-1;
+		} else if (read_pos_cache>rb_write_pos) {
+
+			todo=read_pos_cache-rb_write_pos-1;
+		} else {
+
+			todo=(rb_len-rb_write_pos)+read_pos_cache-1;
+		}
+
+		return todo;
+	}
+
+	_FORCE_INLINE_ int16_t *get_write_buffer() { return read_buf; }
+	_FORCE_INLINE_ void write(uint32_t p_frames) {
+
+		ERR_FAIL_COND(p_frames >= rb_len);
+
+		switch(channels) {
+			case 1: {
+
+				for(uint32_t i=0;i<p_frames;i++) {
+
+					rb[ rb_write_pos ] = read_buf[i];
+					rb_write_pos=(rb_write_pos+1)&rb_mask;
+				}
+			} break;
+			case 2: {
+
+				for(uint32_t i=0;i<p_frames;i++) {
+
+					rb[ (rb_write_pos<<1)+0 ] = read_buf[(i<<1)+0];
+					rb[ (rb_write_pos<<1)+1 ] = read_buf[(i<<1)+1];
+					rb_write_pos=(rb_write_pos+1)&rb_mask;
+				}
+			} break;
+			case 4: {
+
+				for(uint32_t i=0;i<p_frames;i++) {
+
+					rb[ (rb_write_pos<<2)+0 ] = read_buf[(i<<2)+0];
+					rb[ (rb_write_pos<<2)+1 ] = read_buf[(i<<2)+1];
+					rb[ (rb_write_pos<<2)+2 ] = read_buf[(i<<2)+2];
+					rb[ (rb_write_pos<<2)+3 ] = read_buf[(i<<2)+3];
+					rb_write_pos=(rb_write_pos+1)&rb_mask;
+				}
+			} break;
+			case 6: {
+
+				for(uint32_t i=0;i<p_frames;i++) {
+
+					rb[ (rb_write_pos*6)+0 ] = read_buf[(i*6)+0];
+					rb[ (rb_write_pos*6)+1 ] = read_buf[(i*6)+1];
+					rb[ (rb_write_pos*6)+2 ] = read_buf[(i*6)+2];
+					rb[ (rb_write_pos*6)+3 ] = read_buf[(i*6)+3];
+					rb[ (rb_write_pos*6)+4 ] = read_buf[(i*6)+4];
+					rb[ (rb_write_pos*6)+5 ] = read_buf[(i*6)+5];
+					rb_write_pos=(rb_write_pos+1)&rb_mask;
+				}
+			} break;
+
+
+		}
+
+	}
+
+	int get_channel_count() const;
+
+	Error setup(int p_channels, int p_src_mix_rate, int p_target_mix_rate, int p_buffer_msec, int p_minbuff_needed=-1);
+	void clear();
+	bool mix(int32_t *p_dest, int p_frames);
+
+	AudioRBResampler();
+	~AudioRBResampler();
+};
+
+#endif // AUDIO_RB_RESAMPLER_H