/**
 * =========================================================================
 * File        : FileUnpacker.h
 * Project     : 0 A.D.
 * Description : Buffer and 'stream' for reading binary files
 * =========================================================================
 */

#ifndef INCLUDED_FILEUNPACKER
#define INCLUDED_FILEUNPACKER

#include <vector>
#include "lib/res/file/file_io.h"

class CStr8;

#include "ps/Errors.h"
#ifndef ERROR_GROUP_FILE_DEFINED
#define ERROR_GROUP_FILE_DEFINED
// FilePacker.h defines these too
ERROR_GROUP(File);
ERROR_TYPE(File, OpenFailed);
#endif
ERROR_TYPE(File, InvalidType);
ERROR_TYPE(File, InvalidVersion);
ERROR_TYPE(File, ReadFailed);
ERROR_TYPE(File, UnexpectedEOF);

////////////////////////////////////////////////////////////////////////////////
// CFileUnpacker: class to assist in reading of binary files
class CFileUnpacker
{
public:
    // constructor
    CFileUnpacker();

    ~CFileUnpacker();
    
    // Read: open and read in given file, check magic bits against those given; throw 
    // variety of exceptions for missing files etc
    void Read(const char* filename, const char magicstr[4]);
    
    // GetVersion: return stored file version
    u32 GetVersion() const { return m_Version; }

    // UnpackRaw: unpack given number of bytes from the input stream into the given array
    //  - throws PSERROR_File_UnexpectedEOF if the end of the data stream is reached before
    // the given number of bytes have been read
    void UnpackRaw(void* rawdata, u32 rawdatalen);
    // UnpackString: unpack a string from the raw data stream
    void UnpackString(CStr8& result);

private:
    // the data read from file and used during unpack operations
    FileIOBuf m_Buf;
    size_t m_Size;
    // current unpack position in stream
    u32 m_UnpackPos;
    // version of the file currently being read
    u32 m_Version;
};

#endif