//========= Copyright © 1996-2001, Valve LLC, All rights reserved. ============
//
// Purpose: Define the IVoiceCodec interface.
//
// $NoKeywords: $
//=============================================================================

#ifndef IVOICECODEC_H
#define IVOICECODEC_H
#pragma once


#include "interface.h"


#define BYTES_PER_SAMPLE	2


// This interface is for voice codecs to implement.

// Codecs are guaranteed to be called with the exact output from Compress into Decompress (ie:
// data won't be stuck together and sent to Decompress).

// Decompress is not guaranteed to be called in any specific order relative to Compress, but 
// Codecs maintain state between calls, so it is best to call Compress with consecutive voice data
// and decompress likewise. If you call it out of order, it will sound wierd. 

// In the same vein, calling Decompress twice with the same data is a bad idea since the state will be
// expecting the next block of data, not the same block.

class IVoiceCodec
{
protected:
	virtual			~IVoiceCodec() {}

public:
	// Initialize the object. The uncompressed format is always 8-bit signed mono.
	virtual bool	Init()=0;

	// Use this to delete the object.
	virtual void	Release()=0;


	// Compress the voice data.
	// pUncompressed		-	16-bit signed mono voice data.
	// maxCompressedBytes	-	The length of the pCompressed buffer. Don't exceed this.
	// bFinal        		-	Set to true on the last call to Compress (the user stopped talking).
	//							Some codecs like big block sizes and will hang onto data you give them in Compress calls.
	//							When you call with bFinal, the codec will give you compressed data no matter what.
	// Return the number of bytes you filled into pCompressed.
	virtual int		Compress(const char *pUncompressed, int nSamples, char *pCompressed, int maxCompressedBytes, bool bFinal)=0;

	// Decompress voice data. pUncompressed is 16-bit signed mono.
	virtual int		Decompress(const char *pCompressed, int compressedBytes, char *pUncompressed, int maxUncompressedBytes)=0;

	// Some codecs maintain state between Compress and Decompress calls. This should clear that state.
	virtual bool	ResetState()=0;
};


#endif // IVOICECODEC_H
