// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************

    chdcodec.h

    Codecs used by the CHD format

***************************************************************************/
#ifndef MAME_LIB_UTIL_CHDCODEC_H
#define MAME_LIB_UTIL_CHDCODEC_H

#pragma once

#include "utilfwd.h"

#include <cstdint>
#include <memory>
#include <vector>


#define CHDCODEC_VERIFY_COMPRESSION 0


//**************************************************************************
//  TYPE DEFINITIONS
//**************************************************************************

// base types
typedef uint32_t chd_codec_type;


// ======================> chd_codec

// common base class for all compressors and decompressors
class chd_codec
{
protected:
	// can't create these directly
	chd_codec(chd_file &file, uint32_t hunkbytes, bool lossy);

public:
	// allow public deletion
	virtual ~chd_codec();

	// accessors
	chd_file &chd() const { return m_chd; }
	uint32_t hunkbytes() const { return m_hunkbytes; }
	bool lossy() const { return m_lossy; }

	// implementation
	virtual void configure(int param, void *config);

private:
	// internal state
	chd_file &          m_chd;
	uint32_t            m_hunkbytes;
	bool                m_lossy;
};


// ======================> chd_compressor

// base class for all compressors
class chd_compressor : public chd_codec
{
protected:
	// can't create these directly
	chd_compressor(chd_file &file, uint32_t hunkbytes, bool lossy);

public:
	using ptr = std::unique_ptr<chd_compressor>;

	// implementation
	virtual uint32_t compress(const uint8_t *src, uint32_t srclen, uint8_t *dest) = 0;
};


// ======================> chd_decompressor

// base class for all decompressors
class chd_decompressor : public chd_codec
{
protected:
	// can't create these directly
	chd_decompressor(chd_file &file, uint32_t hunkbytes, bool lossy);

public:
	using ptr = std::unique_ptr<chd_decompressor>;

	// implementation
	virtual void decompress(const uint8_t *src, uint32_t complen, uint8_t *dest, uint32_t destlen) = 0;
};


// ======================> chd_codec_list

// wrapper to get at the list of codecs
class chd_codec_list
{
public:
	// create compressors or decompressors
	static chd_compressor::ptr new_compressor(chd_codec_type type, chd_file &file);
	static chd_decompressor::ptr new_decompressor(chd_codec_type type, chd_file &file);

	// utilities
	static bool codec_exists(chd_codec_type type);
	static const char *codec_name(chd_codec_type type);
};


// ======================> chd_compressor_group

// helper class that wraps several compressors
class chd_compressor_group
{
public:
	// construction/destruction
	chd_compressor_group(chd_file &file, chd_codec_type compressor_list[4]);
	~chd_compressor_group();

	// find the best compressor
	int8_t find_best_compressor(const uint8_t *src, uint8_t *compressed, uint32_t &complen);

private:
	// internal state
	uint32_t                m_hunkbytes;        // number of bytes in a hunk
	chd_compressor::ptr     m_compressor[4];    // array of active codecs
	std::vector<uint8_t>    m_compress_test;    // test buffer for compression
#if CHDCODEC_VERIFY_COMPRESSION
	chd_decompressor::ptr   m_decompressor[4];  // array of active codecs
	std::vector<uint8_t>    m_decompressed;     // verification buffer
#endif
};



//**************************************************************************
//  MACROS
//**************************************************************************

constexpr chd_codec_type CHD_MAKE_TAG(char a, char b, char c, char d)
{
	return (uint32_t(uint8_t(a)) << 24) | uint32_t(uint8_t((b)) << 16) | uint32_t(uint8_t((c)) << 8) | uint32_t(uint8_t(d));
}



//**************************************************************************
//  CONSTANTS
//**************************************************************************

// currently-defined codecs
constexpr chd_codec_type CHD_CODEC_NONE     = 0;

// general codecs
constexpr chd_codec_type CHD_CODEC_ZLIB     = CHD_MAKE_TAG('z','l','i','b');
constexpr chd_codec_type CHD_CODEC_ZSTD     = CHD_MAKE_TAG('z','s','t','d');
constexpr chd_codec_type CHD_CODEC_LZMA     = CHD_MAKE_TAG('l','z','m','a');
constexpr chd_codec_type CHD_CODEC_HUFFMAN  = CHD_MAKE_TAG('h','u','f','f');
constexpr chd_codec_type CHD_CODEC_FLAC     = CHD_MAKE_TAG('f','l','a','c');

// general codecs with CD frontend
constexpr chd_codec_type CHD_CODEC_CD_ZLIB  = CHD_MAKE_TAG('c','d','z','l');
constexpr chd_codec_type CHD_CODEC_CD_ZSTD  = CHD_MAKE_TAG('c','d','z','s');
constexpr chd_codec_type CHD_CODEC_CD_LZMA  = CHD_MAKE_TAG('c','d','l','z');
constexpr chd_codec_type CHD_CODEC_CD_FLAC  = CHD_MAKE_TAG('c','d','f','l');

// A/V codecs
constexpr chd_codec_type CHD_CODEC_AVHUFF   = CHD_MAKE_TAG('a','v','h','u');

// A/V codec configuration parameters
enum
{
	AVHUFF_CODEC_DECOMPRESS_CONFIG = 1
};

#endif // MAME_LIB_UTIL_CHDCODEC_H