// Definitions for the Interchange File Format (IFF)

// Alexander Gessler, 2006

// Adapted to Assimp August 2008

#ifndef AI_IFF_H_INCLUDED

#define AI_IFF_H_INCLUDED

#include <assimp/ByteSwapper.h>

namespace Assimp {

namespace IFF {

/////////////////////////////////////////////////////////////////////////////////

//! Describes an IFF chunk header

/////////////////////////////////////////////////////////////////////////////////

struct ChunkHeader

{

    //! Type of the chunk header - FourCC

    uint32_t type;

    //! Length of the chunk data, in bytes

    uint32_t length;

};

/////////////////////////////////////////////////////////////////////////////////

//! Describes an IFF sub chunk header

/////////////////////////////////////////////////////////////////////////////////

struct SubChunkHeader

{

    //! Type of the chunk header - FourCC

    uint32_t type;

    //! Length of the chunk data, in bytes

    uint16_t length;

};

/////////////////////////////////////////////////////////////////////////////////

//! Describes an IFF form header

/////////////////////////////////////////////////////////////////////////////////

struct FormHeader

{

    //! Length of the chunk data, in bytes

    uint32_t length;

    //! Type of the chunk header - FourCC

    uint32_t type;

};

#define AI_IFF_FOURCC(a,b,c,d) ((uint32_t) (((uint8_t)a << 24u) | \

    ((uint8_t)b << 16u) | ((uint8_t)c << 8u) | ((uint8_t)d)))

#define AI_IFF_FOURCC_FORM AI_IFF_FOURCC('F','O','R','M')

/////////////////////////////////////////////////////////////////////////////////

//! Load a chunk header

//! @param outFile Pointer to the file data - points to the chunk data afterwards

//! @return Copy of the chunk header

/////////////////////////////////////////////////////////////////////////////////

inline ChunkHeader LoadChunk(uint8_t*& outFile)

{

    ChunkHeader head;

    ::memcpy(&head.type, outFile, 4);

    outFile += 4;

    ::memcpy(&head.length, outFile, 4);

    outFile += 4;

    AI_LSWAP4(head.length);

    AI_LSWAP4(head.type);

    return head;

}

/////////////////////////////////////////////////////////////////////////////////

//! Load a sub chunk header

//! @param outFile Pointer to the file data - points to the chunk data afterwards

//! @return Copy of the sub chunk header

/////////////////////////////////////////////////////////////////////////////////

inline SubChunkHeader LoadSubChunk(uint8_t*& outFile)

{

    SubChunkHeader head;

    ::memcpy(&head.type, outFile, 4);

    outFile += 4;

    ::memcpy(&head.length, outFile, 2);

    outFile += 2;

    AI_LSWAP2(head.length);

    AI_LSWAP4(head.type);

    return head;

}

/////////////////////////////////////////////////////////////////////////////////

//! Load a chunk header

//! @param outFile Pointer to the file data - points to the chunk data afterwards

//! @return Copy of the chunk header

/////////////////////////////////////////////////////////////////////////////////

inline ChunkHeader LoadForm(uint8_t*& outFile)

{

    ChunkHeader head;

    outFile += 4;

    ::memcpy(&head.length, outFile, 4);

    outFile += 4;

    ::memcpy(&head.type, outFile, 4);

    AI_LSWAP4(head.length);

    AI_LSWAP4(head.type);

    return head;

}

/////////////////////////////////////////////////////////////////////////////////

//! Read the file header and return the type of the file and its size

//! @param outFile Pointer to the file data. The buffer must at

//!   least be 12 bytes large.

//! @param fileType Receives the type of the file

//! @return 0 if everything was OK, otherwise an error message

/////////////////////////////////////////////////////////////////////////////////

inline const char* ReadHeader(uint8_t* outFile, uint32_t& fileType)

{

    ChunkHeader head = LoadChunk(outFile);

    if(AI_IFF_FOURCC_FORM != head.type)

    {

        return "The file is not an IFF file: FORM chunk is missing";

    }

    ::memcpy(&fileType, outFile, 4);

    AI_LSWAP4(fileType);

    return nullptr;

}

}}

#endif // !! AI_IFF_H_INCLUDED