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Annotation of qemu/roms/openbios/forth/packages/deblocker.fs, revision 1.1

1.1     ! root        1: \ tag: deblocker support package
        !             2: \ 
        !             3: \ Copyright (C) 2003 Stefan Reinauer
        !             4: \ 
        !             5: \ See the file "COPYING" for further information about
        !             6: \ the copyright and warranty status of this work.
        !             7: \ 
        !             8: 
        !             9: " /packages" find-device
        !            10: 
        !            11: \ The deblocker package makes it easy to implement byte-oriented device
        !            12: \ methods, using the block-oriented or record-oriented methods defined by 
        !            13: \ devices such as disks or tapes. It provides a layer of buffering between 
        !            14: \ the high-level byte-oriented interface and the low-level block-oriented
        !            15: \ interface. deblocker uses the max-transfer, block-size, read-blocks and
        !            16: \ write-blocks methods of its parent.
        !            17: 
        !            18: new-device
        !            19:   " deblocker" device-name
        !            20:   \ open ( -- flag )
        !            21:   \ Prepares the package for subsequent use, allocating the buffers used 
        !            22:   \ by the deblocking process based upon the values returned by the parent 
        !            23:   \ instance's max-transfer and block-size methods. Returns -1 if the
        !            24:   \ operation succeeds, 0 otherwise.
        !            25:   : open ( -- flag )
        !            26: 
        !            27:     ;
        !            28: 
        !            29:   \ close ( -- )
        !            30:   \ Frees all resources that were allocated by open.
        !            31:   : close ( -- )
        !            32:     ;
        !            33: 
        !            34:   \ read ( adr len -- actual )
        !            35:   \ Reads at most len bytes from the device into the memory buffer 
        !            36:   \ beginning at adr.  Returns actual, the number of bytes actually
        !            37:   \ read, or 0 if the read operation failed. Uses the parent's read-
        !            38:   \ blocks method as necessary to satisfy the request, buffering any
        !            39:   \ unused bytes for the next request.
        !            40:   
        !            41:   : read ( adr len -- actual )
        !            42:     ;
        !            43: 
        !            44:   \ Writes at most len bytes from the device into the memory buffer 
        !            45:   \ beginning at adr.  Returns actual, the number of bytes actually 
        !            46:   \ read, or 0 if the write operation failed. Uses the parent's write-
        !            47:   \ blocks method as necessary to satisfy the request, buffering any 
        !            48:   \ unused bytes for the next request.
        !            49:                                                          
        !            50:   : write ( adr len -- actual )
        !            51:     ;
        !            52: 
        !            53:   \ Sets the device position at which the next read or write will take 
        !            54:   \ place. The position is specified by the 64-bit number x.position. 
        !            55:   \ Returns 0 if the operation succeeds or -1 if it fails.
        !            56: 
        !            57:   : seek ( x.position -- flag )
        !            58:     ;
        !            59: 
        !            60: finish-device
        !            61: 
        !            62: \ clean up afterwards
        !            63: device-end

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