transmission/libtransmission/inout.h

/*
 * This file Copyright (C) 2008-2009 Charles Kerr <charles@transmissionbt.com>
 *
 * This file is licensed by the GPL version 2.  Works owned by the
 * Transmission project are granted a special exemption to clause 2(b)
 * so that the bulk of its code can remain under the MIT license. 
 * This exemption does not extend to derived works not owned by
 * the Transmission project.
 *
 * $Id$
 */

#ifndef __TRANSMISSION__
 #error only libtransmission should #include this header.
#endif

#ifndef TR_IO_H
#define TR_IO_H 1

struct tr_torrent;

/**
 * Reads the block specified by the piece index, offset, and length.
 * @return 0 on success, or an errno value on failure.
 */
int tr_ioRead( const struct tr_torrent * tor,
               tr_piece_index_t          pieceIndex,
               uint32_t                  offset,
               uint32_t                  len,
               uint8_t *                 setme );

/**
 * Writes the block specified by the piece index, offset, and length.
 * @return 0 on success, or an errno value on failure.
 */
int tr_ioWrite( const struct tr_torrent * tor,
                tr_piece_index_t          pieceIndex,
                uint32_t                  offset,
                uint32_t                  len,
                const uint8_t *           writeme );

/**
 * @brief Test to see if the piece matches its metainfo's SHA1 checksum.
 *
 * @param optionalBuffer if calling tr_ioTestPiece() repeatedly, you can
 *                       get best performance by providing a buffer with
 *                       tor->info.pieceSize bytes.
 */
tr_bool tr_ioTestPiece( const tr_torrent * tor,
                        tr_piece_index_t   piece,
                        void             * optionalBuffer,
                        size_t             optionalBufferLen );


/**
 * Converts a piece index + offset into a file index + offset.
 */
void     tr_ioFindFileLocation( const tr_torrent * tor,
                                tr_piece_index_t   pieceIndex,
                                uint32_t           pieceOffset,
                                tr_file_index_t *  fileIndex,
                                uint64_t *         fileOffset );


#endif