IDNT FileCompare ************************************************************************** * * FileCompare - Determines if two specified files have identical contents * * * DESCRIPTION: * The main purpose of this file is to assist automatic generation of * function prototypes files in make scripts. For this purpose, all * that's wanted is a nice, testable exit status, but the program also * sends text to the standard output. * * This is a single-module program. The non-library subroutines used * are all local to this module, and use the on-stack local storage * allocated by the entry-level sequence's LINK instruction as they like. * * The code produced is PURE, and may be made resident. * * * Copyright ©1992 Brian Rhodefer ** ** ** Tabstops : 8 ** To Assemble: Macro68 FileCompare.asm ** ** ** July 19, 1992 ** written ** ** ** FUNCTION & USAGE ** ** FileCompare [Q] ** INCPATH "includes:" OBJFILE "FileCompare" ERRFILE "FileCompare.bugs" LALL PALL HALL SFCOND EXEOBJ LIST LISTFILE "ram:FileCompare.lst" STRICT MC68000 macfile "AllLibraryOffsets.i" macfile "exec/types.i" macfile "libraries/dos.i" macfile "fcMacros.i" section FileCompare,code ; ; Define the template for our local on-stack variables: ; STRUCTURE fileMGMT,0 APTR fHandle CPTR fName LONG fLength LABEL fMGMT_SIZEOF STRUCTURE myStackFrame,0 STRUCT file1,fMGMT_SIZEOF STRUCT file2,fMGMT_SIZEOF APTR outStream STRUCT myFIB,fib_SIZEOF LABEL SFL ; Stands for "Stack Frame Length" BUFSIZE EQU 512 ************************* * COLD ENTRY * ************************* START: jmp (realStart,PC) ; Allegedly, tools can cstr 'fileCompare V0.1' even realStart: link A5,#-SFL ; Reserve our variables move.l D0,D2 ; Make copies of command-line length movea.l A0,A2 ; Initialize pointer to commandline to scan clr.l (file1+fHandle-SFL,A5) clr.l (file2+fHandle-SFL,A5) lea (dosName,PC),a1 ; Try to open the DOS library: moveq.l #33,D0 ; Version 1.2 or better movea.l (4).w,a6 ; Get pointer to Execbase SYSCALL OpenLibrary movea.l D0,A6 tst.l D0 bne.b .dosIsOpen moveq #20,D0 ; This qualifies as a total "FAIL"ure bra.w unlinkAndReturn .dosIsOpen: SYSCALL Output move.l D0,(outStream-SFL,A5) subq.w #2,D2 ; Prepare DBcc index to omit terminator bcs.b .argTrouble ; There should be at least ONE char! ; bsr.w getAnArg ; Find a pointer to file1's name move.l A0,(file1+fName-SFL,A5) beq.b .argTrouble bsr.w getAnArg ; Find a pointer to file2's name move.l A0,(file2+fName-SFL,A5) bne.b .twoLikelyFilenames .argTrouble: bra.w badArgs .twoLikelyFilenames: ; ; Now it's time to find out if our files are there ; lea (file2-SFL,A5),A3 bsr.w myFileOpen move.l D0,D3 ; Save exit status from file 1 attempt lea (file1-SFL,A5),A3 bsr.w myFileOpen and.l D3,D0 beq.b badFiles move.l (fLength-SFL,A5),D6 ; File length remaining cmp.l (file2+fLength-SFL,A5),D6 bne.b filesDontMatch tst.l D6 ; Are they zero-length? beq.b allDone ; If so, they match by definition bsr.w compareFiles allDone: lea (matchString,PC),A0 tst.l D6 beq.b .announceResults lea (differString,PC),A0 .announceResults: bsr.w myPutString closeDown: move.l (file1+fHandle-SFL,A5),D1 beq.b .file1IsGone SYSCALL Close .file1IsGone: move.l (file2+fHandle-SFL,A5),D1 beq.b closeDos SYSCALL Close closeDos: movea.l A6,A1 movea.l (4).w,A6 SYSCALL CloseLibrary move.l D6,D0 unlinkAndReturn: unlk A5 rts badArgs: lea (argsString,PC),A0 bsr.w myPutString moveq #10,D6 ; This is an "ERROR" bra.b closeDos filesDontMatch: moveq #5,D6 ; "WARN" condition bra.b allDone badFiles: moveq #10,D6 bra.b closeDown ******************************************************************************* * * ********************* * * Local subroutines * * ********************* * * * getAnArg - scan through the command line, looking for an argument. * * DESCRIPTION: * Pretty simple, except that arguments with embedded spaces are permitted * if they're enclosed in double quotes per standard AmigaDOS practice. * * INPUTS: * A2 - Pointer to beginning of remaining unscanned portion of command line * D2 - Number of remaining characters in command line * * RETURNS: * A0 - Pointing to first character of name (in other words, what A2 was on entry) * or NULL if no name found getAnArg: tst.l D2 beq.b .badExit moveq #' ',D1 ; Character we're gonna ignore .findFirstChar: cmp.b (A2)+,D1 dbne D2,.findFirstChar beq.b .badExit ; ; Well, we've found a non-blank command line character. ; Is it a double-quote? ; cmpi.b #'"',-(A2) bne.b .foundStart move.b (A2)+,D1 ; If so, that'll become the terminating char .foundStart: movea.l A2,A0 .findLastChar: cmp.b (A2)+,D1 dbeq D2,.findLastChar beq.b .goodExit moveq #0,D2 .goodExit: clr.b (-1,a2) rts .badExit: moveq #0,D2 ; Ensure subsequent calls see "No chars left" movea.l D2,A0 rts ******************************************************************************* * myFileOpen - Attempts to Lock() file designated by the name string of a given * "fileMGMT" structure. If the Lock is obtained, the file's * attributes are obtained using a call to Examine(), and then the * file is Open()ed for reading and unlocked. * * DESCRIPTION: * * * The argument string delimiter * * INPUTS: * A3 - Points to a "fileMGMT" structure * A5 - Points to top of local on-stack variables * A6 - Pointer to Dos library * * RETURNS: * D0 - 1 if the file locked and opened successfully, 0 if there was * a problem. An attempt is made to annunciate problems on the * standard output * ******************************************************************************* myFileOpen: move.l (fName,A3),D1 move.l D1,D6 ; Save pointer to filename moveq #ACCESS_READ,D2 SYSCALL Lock move.l D0,D5 beq.b .fileNotFound ; ; Prepare arguments for call to Examine: ; move.l D0,D1 lea (myFIB-SFL,A5),A0 move.l A0,D2 SYSCALL Examine tst.l D0 beq.b .errNoExamine ; Pretty unlikely... tst.w (myFIB+fib_DirEntryType-SFL,A5) ; Negative if a plain file bpl.b .fileIsDir move.l (myFIB+fib_Size-SFL,A5),(fLength,A3) move.l D6,D1 ; Recover filename pointer move.l #MODE_OLDFILE,D2 SYSCALL Open move.l D0,(A3) beq .locksButWontRead .goodExit: move.l D5,D1 SYSCALL UnLock moveq #1,D0 rts .errNoExamine: lea (examineErrorString,PC),A0 bra.b .complainAndUnlock .fileIsDir: lea (fileIsDirString,PC),A0 bra.b .complainAndUnlock .locksButWontRead: lea (openErrorString,PC),A0 .complainAndUnlock: bsr.b .complainAboutFile bsr.b .goodExit ; re-use the Unlock() call bra.b .errorOut .fileNotFound: lea (lockErrorString,PC),A0 .complainAboutFile: bsr.b myPutString movea.l (fName,A3),A0 bsr.b myPutString lea (closeBracket,PC),A0 bsr.b myPutString .errorOut: moveq #0,D0 aReturn: rts ******************************************************************************* * myPutString - Sends string to standard output via Write() * * DESCRIPTION: * Since we're restricting ourselves to AmigaOS V1.3 features, the only * function available to us for printing messages to the standard output * is to use the Write() call, this subroutine makes things a bit easier * by counting the number of characters in a null-terminated string, in * order to supply Write() with the necessary "length" information * * * * INPUTS: * A0 - Pointer to NULL-terminated string * A5 - Points to top of local on-stack variables * A6 - Pointer to Dos library * * RETURNS: * Nothing. If Write()ing to the standard output doesn't work, we're in * big trouble anyway. Maybe AmigaOS will have kept a an error that the * user can discover by using the "Why" program. * ******************************************************************************* myPutString: move.l (outStream-SFL,A5),D1 ; Fetch pointer to standard output beq.b aReturn moveq #-1,D3 ; We won't be counting the NULL. .sizer: addq.l #1,D3 tst.b (0,A0,D3.w) bne.b .sizer move.l A0,D2 ; Write() wants is buffer-pointer here. jmp (_LVOWrite,A6) ******************************************************************************* * compareFiles - See if open files have identical contents * * DESCRIPTION: * Allocate buffers for both files, in a contiguous fashion (so only 1 call * to AllocMem/FreeMem is needed). Read & compare blocks of each file until * either a difference is found, or the files are exhausted; then deallocate * the buffer. If errors are found, print them. * * * * INPUTS: * A5 - Points to top of local on-stack variables * A6 - Pointer to Dos library * * RETURNS: * D6 - PASS/WARN/FATAL status * compareFiles: move.l #BUFSIZE,D7 move.l D7,D0 add.l D7,D0 ; We'll allocate two contiguous buffers. move.l #MEMF_CLEAR,D1 LIBCALL AllocMem,4 movea.l D0,A4 ; Pointer to our buffer space tst.l D0 beq.b .tooLittleMemory ; ; OK, here's where we do the actual comparison of file contents. ; D7 keeps the buffer size handy. ; D6 keeps track of the number of bytes remaining in the files. ; D5 computes the number of bytes to attempt to read from the files ; A4 holds a pointer to file1's read buffer. File 2's starts bytes after. ; .compareBlock: move.l D7,D5 cmp.l D5,D6 ; Have we fewer than a buffer's worth left? bcc .useD5 move.l D6,D5 ; If so, just ask for the remaining chars. .useD5: ; Read from file #1: move.l (file1+fHandle-SFL,A5),D1 move.l A4,D2 move.l D5,D3 SYSCALL Read move.l D0,D4 ; So we can compare length read in file 2 lea (BUFSIZE,A4),A2 ; Form pointer to buffer for file#2 move.l (file2+fHandle-SFL,A5),D1 move.l A2,D2 move.l D5,D3 SYSCALL Read cmp.l D0,D4 ; Were the same # of chars read from both? bne.b .readPhaseError ; ; Because we're going to stop as soon as we find the first difference ; between the files, and because the two buffers started out equal ; (i.e., cleared), we're going to compare whole longwords at a time, ; and not even bother with the question of partially-filled longwords ; at the end of an incompletely-filled buffer. So long as the number of ; characters read from each file is the same, any such "missed" spots in ; the buffer will match. So, compute a "DBcc loop" termination count for ; the bytes read: ; subq.w #1,D0 lsr.l #2,D0 movea.l A4,A0 ; Pointer to file1's buf. A2=> file 2's. .compareLoop: cmpm.l (A0)+,(A2)+ dbne D0,.compareLoop bne.b .filesDontMatch sub.l D4,D6 ; How many characters remain? bhi .compareBlock .closeBuf move.l D7,D0 add.l D7,D0 movea.l A4,A1 move.l A4,D1 beq.b .bufIsGone EXECLIB FreeMem .bufIsGone: rts .filesDontMatch: moveq #5,D6 ; This is a "WARN" condition bra.b .closeBuf .readPhaseError: lea (badLengthString,PC),A0 .lastWord: bsr.w myPutString clr.l (outStream-SFL,A5) ; Squelch any further error output moveq #10,D6 ; This is an "ERROR" condition bra.s .closeBuf .tooLittleMemory: lea (noBufString,PC),A0 bra.b .lastWord ******************************************************************************* ; STRINGS ESCAPESTR dosName: DOSNAME examineErrorString: CSTR 'Can''t examine file <' lockErrorString: CSTR 'Can''t find file <' openErrorString: CSTR 'Can''t open file <' fileIsDirString: CSTR 'Specified file is directory: <' closeBracket: CSTR '>\N' badLengthString: CSTR 'Non-matching read lengths\N' matchString: CSTR 'Files are identical\N' differString: CSTR 'Files are dissimilar\N' noBufString: CSTR 'Couldn''t allocate compare buffer\N' argsString: CSTR 'Usage: fileCompare \N' versionString: CSTR '$VER: fileCompare 1.0 (20.7.92)' ******************************************************************************* END