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Annotation of qemu/roms/openbios/forth/packages/deblocker.fs, revision 1.1.1.1

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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