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125 lines
4.4 KiB
Plaintext
125 lines
4.4 KiB
Plaintext
;
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; File: MFSRFN1.a
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;
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; Contains: This file contains routines for MFS cache I/O.
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;
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; Copyright: © 1982-1991 by Apple Computer, Inc., all rights reserved.
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;
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; Change History (most recent first):
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;
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; <2> 9/12/91 JSM Add a header.
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; <1.1> 11/10/88 CCH Fixed Header.
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; <1.0> 11/9/88 CCH Adding to EASE.
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; <1.0> 2/11/88 BBM Adding file for the first time into EASE…
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; 10/1/85 LAK Most code moved to Cache and TFSRfn1.
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; 9/6/85 LAK Tag data Time field is now set correctly. Call MFSRWSub instead
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; of MyRWSub since D3 disk block is word length for MFS.
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; 8/15/85 PWD Added code to save A6 before ,ASYNC calls
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; 7/1/85 PWD Changed to use A6 stack to save context
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; 3/1/85 GJC Limited MFS to portions of routines not handled by TFS
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; 6/27/84 GSS Put in line the WrPart patch from MSFileFix
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; 8/30/83 LAK Removed redundant set of FCB dirty bit in FileWrite (gets set by
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; AdjEOF).
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; 8/15/83 LAK Flushes file buffer now if block is dirty and falls within
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; read-in-place . . . saved some bytes, too.
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; 8/11/83 LAK Added support for a read-verify mode.
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; 8/2/83 LAK Fixed read bug (read count 0 with position past EOF). Changed
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; file positioning mode 2 (relative to end of file) by defining
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; IOPosOffset to be either positive or negative . . .
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; 6/2/83 LAK Changes for FCBBfAdr=0 meaning use volume buffer.
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; 2/10/83 LAK Fixed bugs in Read with EOL character.
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; 2/9/83 LAK Fixed MyWriteIP bug (now invalidates file's buffer if it happens
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; to write that block . . .)
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; 1/17/83 LAK Latest changes for final structures. Brought SetFPos and GetFPos
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; here from FSRFN2. Made GetFPos and SetFPos call FileRead with
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; zero bytes requested.
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; 12/14/82 LAK Rewrote for new file system data structures.
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;
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;_______________________________________________________________________
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;
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; External Routines: None
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;
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; Internal Routines: MFSRd1stDB,MFSRdNxtDB,MFSDirRead,MFSMapRead,MFSVolRead.
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;
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;_______________________________________________________________________
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;
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;_______________________________________________________________________
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;
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; Routine: MFSRd1stDB,MFSRdNxtDB
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; Arguments: A2.L (input) -- VCB ptr
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; D0.W (output) -- error code
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; A5.L (output) -- ptr to buffer
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; Clobbers: D4,A6
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; Preserves: D1,D2,D5,D6,D7,A0,A1,A2,A3,A4
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; others: see MyReadDB
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; Calls: MyReadDB,GetCurBlk
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; Called By: FndFilNam,FndFilSpc
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; Function: These two routines are used when scanning through a volume
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; directory for a filename or for space. Rd1stDB must be
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; called for the first block as it sets up certain lomem
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; variables (MaxDB). RdNxtDB is called for
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; remaining blocks (if any).
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;
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;_______________________________________________________________________
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; Called By: MFSMount (consistency check)
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; FndMFSFile (directory search)
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; FndFilSpc (looking for space for Create, Rename)
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MFSRd1stDB:
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BLANKS ON
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STRING ASIS
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MOVE.W VCBBlLn(A2),D0 ; len in blocks of dir
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MOVE.W VCBDirSt(A2),D3 ; starting block of dir on disk
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ADD.W D3,D0 ; make D4=ptr to last dir blk+1
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MOVE.W D0,MaxDB ; max DB block + 1
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BRA.S MFSDirRead
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; A2=VCB ptr
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; MaxDB=last DB+1
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; NxtDB=next DB to check
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MFSRdNxtDB:
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MOVE.W CurDB,D3 ; next block to read
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ADDQ.W #1,D3 ; and increment this field
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CMP.W MaxDB,D3 ; past the last block?
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BCS.S MFSDirRead ; br if not
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MOVEQ #DirFulErr,D0 ; the directory may be full
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RTS
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; Called By: MFSCLose (find block for update)
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; MFSRd1stDB, MFSRdNxtDB (directoy searches)
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MFSDirRead:
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MOVE.W D3,CurDB ; save current directory block <01Oct85>
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BSR ReadBlock
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MOVE.L SysCtlCPtr,A1 ; catalog blk read: MFS catalog blks <01Oct85>
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BRA.S MFSMapR2
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; Function: Get a volume map/master directory block.
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; Called By: MFSMount
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MFSVolRead
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BSR ReadBlock ; use common code, pass ptr to next inst
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BRA.S MFSMapR1 ; share code with map read
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; Function: Get a volume map/master directory block without reading it first.
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; Called By: MFSFlush
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MFSMapRead:
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BSR ReadBlock ; use common code, pass ptr to next inst
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MOVEQ #kGBNoRead,D1 ; don't bother to read it <01Oct85>
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MFSMapR1:
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MOVE.L SysVolCPtr,A1 ; Use volume cache for MFS vol reads <01Oct85>
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MFSMapR2:
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MOVEQ #0,D2 ; clear high word
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MOVE.W D3,D2 ; block number <01Oct85>
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MOVE.W VCBVRefNum(A2),D0 ; volume refnum <01Oct85>
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RTS ; return to ReadBlock <01Oct85>
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