//========= Copyright Valve Corporation, All rights reserved. ============//
//
//  LZMA Codec interface for engine.
//
//  LZMA SDK 9.38 beta
//  2015-01-03 : Igor Pavlov : Public domain
//  http://www.7-zip.org/
//
//========================================================================//

#ifndef _LZMADECODER_H
#define _LZMADECODER_H
#pragma once

// Thanks for the useful define namespacing, LZMA
#include "../../utils/lzma/C/7zVersion.h"
#define LZMA_SDK_VERSION_MAJOR MY_VER_MAJOR
#define LZMA_SDK_VERSION_MINOR MY_VER_MINOR

#if !defined(_X360)
#define LZMA_ID (('A' << 24) | ('M' << 16) | ('Z' << 8) | ('L'))
#else
#define LZMA_ID (('L' << 24) | ('Z' << 16) | ('M' << 8) | ('A'))
#endif

// bind the buffer for correct identification
#pragma pack(1)
struct lzma_header_t {
    unsigned int id;
    unsigned int actualSize;  // always little endian
    unsigned int lzmaSize;    // always little endian
    unsigned char properties[5];
};
#pragma pack()

class CLZMAStream;

class CLZMA {
   public:
    static unsigned int Uncompress(unsigned char *pInput,
                                   unsigned char *pOutput);
    static bool IsCompressed(unsigned char *pInput);
    static unsigned int GetActualSize(unsigned char *pInput);
};

// For files besides the implementation, we forward declare a dummy struct. We
// can't unconditionally forward declare this because LzmaEnc.h typedefs this
// directly to an unnamed struct :-/
#ifndef CLzmaDec_t
struct _CLzmaDec_t;
#define CLzmaDec_t struct _CLzmaDec_t
#endif

class CLZMAStream {
   public:
    CLZMAStream();
    ~CLZMAStream();

    // Initialize a stream to read data from a LZMA style zip file, passing the
    // original size from the zip headers. Streams with a source-engine style
    // header (lzma_header_t) do not need an init call.
    void InitZIPHeader(unsigned int nCompressedSize,
                       unsigned int nOriginalSize);

    // Attempt to read up to nMaxInputBytes from the compressed stream, writing
    // up to nMaxOutputBytes to pOutput. Makes progress until blocked on input
    // or output. Returns false if read stops due to an error or if called at
    // EOF (GetExpectedBytesRemaining == 0)
    bool Read(unsigned char *pInput, unsigned int nMaxInputBytes,
              unsigned char *pOutput, unsigned int nMaxOutputBytes,
              /* out */ unsigned int &nCompressedBytesRead,
              /* out */ unsigned int &nOutputBytesWritten);

    // Get the expected uncompressed bytes yet to be read from this stream.
    // Returns false if not yet known, such as before being fed the header.
    bool GetExpectedBytesRemaining(/* out */ unsigned int &nBytesRemaining);

   private:
    enum eHeaderParse {
        eHeaderParse_OK,
        eHeaderParse_Fail,
        eHeaderParse_NeedMoreBytes
    };

    eHeaderParse TryParseHeader(unsigned char *pInput,
                                unsigned int nBytesAvailable,
                                /* out */ unsigned int &nBytesConsumed);

    void FreeDecoderState();
    bool CreateDecoderState(const unsigned char *pProperties);

    // Init from a zip-embedded LZMA stream. Requires the original size be
    // passed from zip headers.
    CLzmaDec_t *m_pDecoderState;

    unsigned int m_nActualSize;
    unsigned int m_nActualBytesRead;
    unsigned int m_nCompressedSize;
    unsigned int m_nCompressedBytesRead;

    // If we have read past the header
    bool m_bParsedHeader : 1;
    // If InitZIPHeader() was called. We're expecting a zip-style header and
    // have size information.
    bool m_bZIPStyleHeader : 1;
};

#endif