ttfile.c

神龙卡开发原代码

 *            filepathname   pathname of the file to open
 *            stream         address of target TT_Stream structure
 *
 *  Output :  SUCCESS on sucess, FAILURE on error.
 *            The target stream is set to -1 in case of failure.
 *
 ******************************************************************/

  LOCAL_FUNC
  TT_Error  TT_Open_Stream( const TT_Text*  filepathname,
                            TT_Stream*      stream )
  {
    Int          len;
    TT_Error     error;
    PStream_Rec  stream_rec;

    if ( ALLOC( *stream, sizeof ( TStream_Rec ) ) )
      return error;

    stream_rec = STREAM2REC( *stream );

    stream_rec->file     = NULL;
    stream_rec->size     = -1L;
    stream_rec->base     = 0;
    stream_rec->opened   = FALSE;
    stream_rec->position = 0;

    len = strlen( filepathname ) + 1;
    if ( ALLOC( stream_rec->name, len ) )
      goto Fail;

    strncpy( stream_rec->name, filepathname, len );

    error = Stream_Activate( stream_rec );
    if ( error )
      goto Fail_Activate;

#ifndef TT_CONFIG_OPTION_THREAD_SAFE
    CUR_Stream = stream_rec;
#endif

    return TT_Err_Ok;

  Fail_Activate:
    FREE( stream_rec->name );
  Fail:
    FREE( stream_rec );
    return error;
  }


/*******************************************************************
 *
 *  Function    : TT_Close_Stream
 *
 *  Description : Closes a stream.
 *
 *  Input  :  stream         address of target TT_Stream structure
 *
 *  Output :  SUCCESS (always).
 *
 ******************************************************************/

  LOCAL_FUNC
  TT_Error  TT_Close_Stream( TT_Stream*  stream )
  {
    PStream_Rec  rec = STREAM2REC( *stream );


    Stream_Deactivate( rec );
    FREE( rec->name );
    FREE( rec );

    HANDLE_Set( *stream, NULL );
    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    : TT_Flush_Stream
 *
 *  Description : Flushes a stream, i.e., closes its file handle.
 *
 *  Input  :  stream         address of target TT_Stream structure
 *
 *  Output :  Error code
 *
 *  NOTE : Never flush the current opened stream.  This means that
 *         you should _never_ call this function between a
 *         TT_Use_Stream() and a TT_Done_Stream()!
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Flush_Stream( TT_Stream*  stream )
  {
    PStream_Rec  rec = STREAM2REC( *stream );


    if ( rec )
    {
      Stream_Deactivate( rec );
      return TT_Err_Ok;
    }
    else
      return TT_Err_Invalid_Argument;
  }


/*******************************************************************
 *
 *  Function    : TT_Seek_File
 *
 *  Description : Seeks the file cursor to a different position.
 *
 *  Input  :  position     new position in file
 *
 *  Output :  SUCCESS on success.  FAILURE if out of range.
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Seek_File( STREAM_ARGS Long  position )
  {
    position += CUR_Stream->base;

    if ( fseek( CUR_Stream->file, position, SEEK_SET ) )
      return TT_Err_Invalid_File_Offset;

    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    : TT_Skip_File
 *
 *  Description : Skips forward the file cursor.
 *
 *  Input  :  distance    number of bytes to skip
 *
 *  Output :  see TT_Seek_File()
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Skip_File( STREAM_ARGS Long  distance )
  {
    return TT_Seek_File( STREAM_VARS ftell( CUR_Stream->file ) -
                                     CUR_Stream->base + distance );
  }


/*******************************************************************
 *
 *  Function    : TT_Read_File
 *
 *  Description : Reads a chunk of the file and copies it to memory.
 *
 *  Input  :  buffer    target buffer
 *            count     length in bytes to read
 *
 *  Output :  SUCCESS on success.  FAILURE if out of range.
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Read_File( STREAM_ARGS void*  buffer, Long  count )
  {
    if ( fread( buffer, 1, count, CUR_Stream->file ) != (ULong)count )
      return TT_Err_Invalid_File_Read;

    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    : TT_Read_At_File
 *
 *  Description : Reads file at a specified position.
 *
 *  Input  :  position  position to seek to before read
 *            buffer    target buffer
 *            count     number of bytes to read
 *
 *  Output :  SUCCESS on success.  FAILURE if error.
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Read_At_File( STREAM_ARGS Long   position,
                                         void*  buffer,
                                         Long   count )
  {
    TT_Error  error;


    if ( (error = TT_Seek_File( STREAM_VARS position ))      != TT_Err_Ok ||
         (error = TT_Read_File( STREAM_VARS buffer, count )) != TT_Err_Ok )
      return error;

    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  TT_File_Pos
 *
 *  Description :  Returns current file seek pointer.
 *
 *  Input  :  none
 *
 *  Output :  Current file position.
 *
 ******************************************************************/

  EXPORT_FUNC
  Long  TT_File_Pos( STREAM_ARG )
  {
    return ftell( CUR_Stream->file ) - CUR_Stream->base;
  }


/*******************************************************************
 *
 *  Function    :  GET_Byte
 *
 *  Description :  Extracts a byte from the current file frame.
 *
 *  Input  :  None or current frame
 *
 *  Output :  Extracted Byte.
 *
 ******************************************************************/
#if 0
  EXPORT_FUNC
  Byte  TT_Get_Byte( FRAME_ARG )
  {
    CHECK_FRAME( CUR_Frame, 1 );

    return (Byte)(*CUR_Frame.cursor++);
  }
#endif


/*******************************************************************
 *
 *  Function    :  GET_Char
 *
 *  Description :  Extracts a signed byte from the current file frame.
 *
 *  Input  :  None or current frame
 *
 *  Output :  Extracted char.
 *
 ******************************************************************/
  EXPORT_FUNC
  Char  TT_Get_Char( FRAME_ARG )
  {
    CHECK_FRAME( CUR_Frame, 1 );

    return (Char)(*CUR_Frame.cursor++);
  }


/*******************************************************************
 *
 *  Function    :  GET_Short
 *
 *  Description :  Extracts a short from the current file frame.
 *
 *  Input  :  None or current frame
 *
 *  Output :  Extracted short.
 *
 ******************************************************************/

  EXPORT_FUNC
  Short  TT_Get_Short( FRAME_ARG )
  {
    Short  getshort;


    CHECK_FRAME( CUR_Frame, 2 );

    getshort = (Short)((CUR_Frame.cursor[0] << 8) |
                        CUR_Frame.cursor[1]);

    CUR_Frame.cursor += 2;

    return getshort;
  }


/*******************************************************************
 *
 *  Function    :  GET_UShort
 *
 *  Description :  Extracts an unsigned short from the frame.
 *
 *  Input  :  None or current frame
 *
 *  Output :  Extracted ushort.
 *
 ******************************************************************/
#if 0
  EXPORT_FUNC
  UShort  TT_Get_UShort( FRAME_ARG )
  {
    UShort  getshort;


    CHECK_FRAME( CUR_Frame, 2 );

    getshort = (UShort)((CUR_Frame.cursor[0] << 8) |
                         CUR_Frame.cursor[1]);

    CUR_Frame.cursor += 2;

    return getshort;
  }
#endif


/*******************************************************************
 *
 *  Function    :  GET_Long
 *
 *  Description :  Extracts a long from the frame.
 *
 *  Input  :  None or current frame
 *
 *  Output :  Extracted long.
 *
 ******************************************************************/

  EXPORT_FUNC
  Long  TT_Get_Long( FRAME_ARG )
  {
    Long  getlong;


    CHECK_FRAME( CUR_Frame, 4 );

    getlong = ((Long)CUR_Frame.cursor[0] << 24) |
              ((Long)CUR_Frame.cursor[1] << 16) |
              ((Long)CUR_Frame.cursor[2] << 8 ) |
               (Long)CUR_Frame.cursor[3];

    CUR_Frame.cursor += 4;

    return getlong;
  }


/*******************************************************************
 *
 *  Function    :  GET_ULong
 *
 *  Description :  Extracts an unsigned long from the frame.
 *
 *  Input  :  None or current frame
 *
 *  Output :  Extracted ulong.
 *
 ******************************************************************/
#if 0
  EXPORT_FUNC
  ULong  TT_Get_ULong( FRAME_ARG )
  {
    ULong  getlong;


    CHECK_FRAME( CUR_Frame, 4 );

    getlong = ( ((ULong)CUR_Frame.cursor[0] << 24) |
                ((ULong)CUR_Frame.cursor[1] << 16) |
                ((ULong)CUR_Frame.cursor[2] << 8 ) |
                 (ULong)CUR_Frame.cursor[3] );

    CUR_Frame.cursor += 4;

    return getlong;
  }
#endif


/* END */