***************************** DISK & FILE ******************************* ASMLIB disk & file subroutines (C) Copyright 1992 - 1993 Douglas Herr All rights reserved The MS-DOS file attribute byte tells you whether a file is read-only, system, a subdirectory, or may provide other information. File attribute bits may be combined. Each bit of the file attribute means: 0 = normal files 1 = read-only 2 = hidden files 4 = system files 8 = volume label (only one per disk) 16 = subdirectories 32 = archive bit set Thus a file with an attribute of 18 is a hidden subdirectory (16 OR 2) ASMLIB buffered file I/O system Several ASMLIB subroutines are available for buffered file Input or Output. Files to be managed by the buffered I/O system must be opened by FOPEN or FCREATE, and must be closed by FCLOSE. Buffered file I/O will be much faster than unbuffered. ASMLIB's default buffer size is 4096 bytes; this can be changed by altering FBUFFER_SIZE in FOPEN.ASM and re-assembling. Up to 20 files can be managed by FOPEN; this can be changed by altering NUMBER_OF_FILES in $handle.asm and reassembling. All ASMLIB file buffer subroutines assume DS:@data. To use the ASMLIB buffered I/O system excess DOS memory must be released. See ENDPROG in SYSTEM.DOC. Subroutines: FOPEN open file & initialize buffer FCREATE create file & initialize buffer FCLOSE flush & close output buffer; close file FSEEK move file pointer & update buffer FGETSTR read a string from buffer FGETCHR read a character from buffer FGET read specified number of bytes from buffer FPUTSTR write string to buffer FPUTCRLF write CR+LF to buffer FPUTCHR write character to buffer FPUT write specified number of bytes to buffer 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� DISKWP: determines if a floppy disk is write-protected Source: diskwp.asm Call with: DL = floppy disk number (drive A: = 0) Returns: AL = BIOS error code 0 = no error 1 = invalid disk number 3 = disk is write-protected 128 = drive not ready Uses: AX, flags Supports: physical drives A: and B: Example: include asm.inc public mycode extrn diskwp:proc .code diskwp proc . . . mov dl,1 ; drive B: call diskwp ; can I write to this disk? or al,al jz no_problem 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� DOTBAK: changes the file extension of an existing file to .BAK Source: dotbak.asm (strrchr.asm) Call with: DS:[SI] = address of a ASCIIZ valid filename assumes DS:@data dotbak deletes a previous .BAK file of this name and renames the input filename.ext to filename.bak. Returns: if CF = 0, no error if CF = 1, AL = DOS error code. If AL = 5, the previous .BAK filename is probably read-only. All other errors refer to the name change operation. Uses: AX, flags Example: extrn dotbak:proc .data disk_doc db 'DISK.DOC',0 .code ; program fragment assumes DS:@data . . . mov si,offset DGROUP:disk_doc call dotbak 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FCLOSE: close a file managed by ASMLIB's buffered file I/O system Source: fopen.asm ($handle.asm, dosalloc.asm) Call with: BX = file handle The file must have been opened by FOPEN or FCREATE; If the file is not read-only, the output buffer will be written to the disk file before closing the file. Returns: if CF = 0, no error if CF = 1, AX = error code Uses: AX, flags Example: see FOPEN 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FCOPY: copy a file FCOPYM: copy a file using supplied memory buffer Source: fcopy.asm Call with: DS:[SI] = address of source filename ES:[DI] = address of destination filename Both filenames must be ASCIIZ strings. Drive and path need not be fully specified; filenames may not include * or ? wildcards. FCOPY only: Requires 64k DOS memory available FCOPYM only: AX = segment address of 64k buffer Returns: if CF = 0, no problem if CF = 1, AX = DOS error code (AX = -1 if insufficient memory) Uses: AX, CF Example: .data db 'b:' source db 'asmlib.lib',0 ; copy the library to b: extrn fcopy:proc .code ; program fragment assumes DS:@data . . push ds pop es assume es:@data lea si,source mov di,si ; DI also points to source sub di,2 ; back the pointer to the 'B:' call fcopy jc oops 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FCOUNT: counts the number of files matching an ASCIIZ filespec string. The filespec string may include the '*' and '?' wildcards. Source: fcount.asm Call with: DS:[DX] pointing to filespec string CX = file attributes assumes DS:@data Returns: AX = number of files matching the filespec string Uses: AX, all other registers and flags are saved Example: .code ; program fragment assumes DS:@data . . . lea dx,filespec ; address of filespec string xor cx,cx ; normal files only call fcount 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FCREATE: create new file and initialize output buffer Source: fcreate.asm ($handle.asm, dosalloc.asm) Call with: DS:[DX] pointing to ASCIIZ filename The file is created with write-only access. If a file with the same name already exists, it is truncated to zero length by FCREATE. Returns: if CF = 0, AX = file handle if CF = 1, AX = error code Uses: AX, flags Example: include asm.inc public myprog extrn fcreate:proc .data file_name db 'ANYNEW.FIL',0 file_handle dw 0 .code myprog proc ; program fragment assumes DS:@data . . . lea dx,file_name call fcreate jc something_went_wrong mov file_handle,ax ; save the handle . . . 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FEXIST: determines if a file exists and can be opened with read access Source: fexist.asm Call with: DS:[DX] pointing to ASCIIZ filename Returns: if CF = 0, file exists if CF = 1, AX = MS-DOS error code Uses: AX, CF; all other flags and registers are saved Example: include asm.inc extrn fexist:proc .data filename db 'asmlib.doc',0 .code ; program fragment assumes DS:@data . . . lea dx,filename call fexist jnc got_the_file ; if CF = 0, go on jmp doserror ; else go to error handling code 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FFLUSH: flushes the ASMLIB and DOS output buffers for specified handle Source: fflush.asm (fseek.asm, $handle.asm) Call with: BX = file handle flushing the buffers guards against data loss in case of system failure, such as power loss Returns: if CF = 0, no error; function successful if CF = 1, AX = DOS error code Uses: AX, flags Example: include asm.inc extrn fflush:proc .code ; program opens file & writes to file . . . ; flush the buffers to disk mov bx,handle call fflush 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FGET: read specified number of bytes from file buffer Source: fget.asm ($handle.asm, $fget.asm) Call with: BX = file handle CX = number of bytes requested (up to 4096 bytes) Returns: if CF = 0, AX = number of bytes read ES:[BX] points to data in buffer if CF = 1, AX = DOS error code Uses: AX, BX, ES, flags Example: include asm.inc extrn fopen:proc, fget:proc .data file_name db 'asmlib.doc',0 file_handle dw 0 .code ; program fragment assumes DS:@data . . . lea dx,file_name call fopen jc fopen_problem mov file_handle,ax ; save for later mov bx,ax ; file handle mov cx,8 ; I want 8 bytes call fget ; returned at ES:[BX] jc read_problem ; uh oh, trouble ... cmp ax,cx ; did I get what I wanted? jne not_enough . . 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FGETCHR: read a character from a file buffer Source: fgetchr.asm ($handle.asm) Call with: BX = file handle Returns: if CF = 0, AL = next character from file buffer if CF = 1, AX = DOS error code AX = 0 if at end of file Uses: AX, flags Example: include asm.inc extrn fopen:proc, fgetchr:proc .data file_name db 'asmlib.doc',0 file_handle dw 0 .code ; program fragment assumes DS:@data . . . lea dx,file_name call fopen jc fopen_problem mov file_handle,ax ; save for later mov bx,ax ; file handle call fgetchr ; character in AL jc read_problem . . 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FGETSTR: read an ASCII string from a file buffer Source: fgetstr.asm ($handle.asm, $fget.asm) Call with: BX = file handle ASCII strings may be terminated with either 0Dh or 0Dh+0Ah. After reading each string, FGetStr positions the buffer pointer to read the next string. String length should be less than the buffer size. See FOPEN. Returns: if CF = 0, ES:[BX] points to string in buffer CX = length of ASCII string if CX = byte length of buffer, string >= size of buffer if CF = 1, AX = DOS error code AX = 0 if end of file Uses: ES, BX, AX, CX, flags Example: include asm.inc extrn fopen:proc, fgetstr:proc .data file_name db 'asmlib.doc',0 file_handle dw 0 .code ; program fragment assumes DS:@data . . . lea dx,file_name call fopen jc fopen_problem mov file_handle,ax ; save for later mov bx,ax ; file handle call fgetstr jc read_problem call strndup ; make a copy in near heap for later . . . 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FILELIST: creates a list of file names matching a filespec mask Source: filelist.asm (fcount.asm, dosalloc.asm) Call with: DS:[SI] pointing to filespec mask CX = file attribute mask Returns: if CF = 0: ES = base segment address of list buffer AX = number of filenames in list CX = list field width if CF = 1, AX = MS-DOS error code You should use DOS function 49h to release the file list buffer when you're done with it. Uses: AX, CX, ES, CF Example: include asm.inc public myproc .data filespec db '*.*',0 .code ; program fragment assumes DS:@data . . . lea si,filespec mov cx,16 ; normal files and subdirectories call filelist jc cant_do_it ; oops 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FINDDATE: given a successful call to FindFirst or FindNext, returns the file's date stamp Source: findfile.asm Call with: DS:[BX] pointing to DTA buffer; assumes DS @DATA Returns: DX = month AX = day CX = year Uses: AX, CX, DX, flags Example: .code ; program fragment assumes DS:@data . . . lea bx,filespec mov cx,0 ; normal files only call findfirst ; find first matching file jc no_more_files cmp ax,-1 je no_more_files call finddate 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FINDFIRST: This subroutine, when used with FindNext, finds files on a disk which match an ASCIIZ filespec string. The filespec string may contain the '*' and '?' wildcards. Source: findfile.asm (heap.asm) Call with: DS:[BX] pointing to ASCIIZ filespec string; assumes DS:@data CX = file attribute mask FindFirst allocates space for a local DTA buffer from the near heap. See FindNext; also see HINIT. Returns: AX = error code -1 = insufficient memory in near heap (128 bytes required) 0 = no error CF = 1 if no files match the filespec string DS:[BX] -> DTA buffer if the subroutine is successful. Do not alter the 128 bytes in the DTA buffer. The name of the file is an ASCIIZ string at 30[BX] The file attribute is a byte at 21[BX] The low word of the file's size is at 26[BX] The high word of the file's size is at 28[BX] Uses: AX, BX, flags Example: .code ; program fragment assumes DS:@data . . . lea bx,filespec mov cx,0 ; normal files only call findfirst ; find first matching file jc no_more_files cmp ax,-1 je no_memory ; memory not available ; print the filename on the screen tprint_next: mov si,bx add si,30 ; point to filename in DTA buffer mov dh,count ; row value mov dl,0 ; column 0 mov ah,12 ; color attribute - RED! call tprint ; display the file name on the screen inc count ; next filename on next row call findnext ; any more matching filenames? jnc tprint_next no_more_files: 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FINDNEXT: finds file matching search string; use after FindFirst. used only after a successful call to FindFirst. Source: findfile.asm (heap.asm) Call with: no parameters; assumes DS:@data FindNext de-allocates the DTA buffer space after the first unsuccessful search for a matching file. Returns: DS:[BX] -> DTA buffer CF = 1 if no more files match the filespec string. Uses: BX, flags Example: see FindFirst. 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FINDTIME: given a successful call to FindFirst or FindNext, returns the file's time stamp Source: findfile.asm Call with: DS:[BX] pointing to DTA buffer; assumes DS:@data Returns: DX = hour AX = minute CX = second Uses: AX, CX, DX, flags Example: lea bx,filespec mov cx,0 ; normal files only call findfirst ; find first matching file jc no_more_files cmp ax,-1 je no_more_files call findtime 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FOPEN: opens existing file and initializes ASMLIB buffered I/O Source: fopen.asm (dosalloc.asm, $handle.asm) Call with: DS:[DX] pointing to name of file to be opened AL = access mode 0 = read-only access 1 = write-only access 2 = read-write access NOT SUPPORTED YET Returns: if CF = 0, AX = file handle if CF = 1, AX = ASMLIB or DOS error code; file not opened if AX = 0, insufficient DOS memory available if AX = 0FFFFh, no handles available in ASMLIB I/O array; change NUMBER_OF_HANDLES in $handle.asm amd re-assemble (default = 20 handles) Uses: AX, flags Example: include asm.inc public myprog extrn fopen:proc, fclose:proc .data file_name db 'ASMLIB.DOC',0 file_handle dw 0 .code myprog proc ; program fragment assumes DS:@data . . . lea dx,file_name xor al,al ; read-only access call fopen jc something_went_wrong mov file_handle,ax ; save the handle . . . ; all done with this file mov bx,file_handle call fclose 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FPUT: write specified number of bytes to output file buffer Source: fput.asm ($handle.asm) Call with: BX = file handle ES:[DI] pointing to data to write CX = number of bytes to write Returns: if CF = 0, no error if CF = 1, AX = error code Uses: AX, flags Example: include asm.inc public myproc extrn fput:proc extrn fputchr:proc extrn fputcrlf:proc .data data1 db 'several bytes may be written at once' data_len equ $-data1 .code ; program fragment assumes DS:@data . . . mov bx,output_handle push ds pop es ; ES = DS = DGROUP assume es:DGROUP lea di,data1 ; ES:[DI] -> data1 mov cx,data_len ; bytes to write call fput call fputcrlf ; write CR+LF for new line ; in ASCII text file mov al,26 ; End-of-File byte (optional) call fputchr 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FPUTCHR: write one character to output file buffer Source: fputchr.asm (fput.asm) Call with: BX = output file handle AL = character to write Returns: if CF = 1, AX = MS-DOS error code if CF = 0, no error Uses: AX, flags Example: see FPUT 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FPUTCRLF: write CR+LF pair to output file buffer Source: fputcrlf.asm (fput.asm) Call with: BX = output file handle; file must have been opened by FOPEN or FCREATE Returns: if CF = 0, no error if CF = 1, AX = DOS error code Uses: AX, flags Example: see FPUT 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FPUTSTR: write an ASCIIZ string to output buffer Source: fpustr.asm (strlen.asm, fput.asm) Call with: BX = file handle ES:[DI] points to ASCIIZ string Returns: if CF = 0, AX = bytes written if CF = 1, AX = DOS error code Uses: AX, flags Example: include asm.inc public myproc extrn fputstr:proc extrn fputcrlf:proc .data strptr dw 0 ; pointer to string, assigned by program .code ; program fragment assumes DS:@data . . . push ds pop es ; ES = DS = DGROUP assume es:DGROUP mov bx,output_handle mov di,strptr ; ES:[DI] -> data1 call fputstr call fputcrlf ; write CR+LF for new line ; in ASCII text file 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FSEEK: move file pointer for a file opened by FOPEN Source: fseek.asm ($handle.asm) Call with: BX = file handle AL = method code: 0 = absolute offset from start of file 1 = signed offset from current file pointer 2 = signed offset from end of file CX:DX = dword offset Returns: if CF = 1, AX = DOS error code if CF = 0, DX:AX = current location of file pointer Uses: AX, DX, flags Example: include asm.inc public whoknows extrn fopen:proc, fseek:proc .data file0 db 'file0.dat',0 .code whoknows proc ; program fragment assumes DS:@data . . . mov dx,offset DGROUP:file0 mov al,1 ; write only call fopen jc error xor cx,cx mov dx,cx ; zero offset mov al,2 ; relative to end of file call fseek ; move pointer to end of file 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� FSIZE: determines a file's size Source: fsize.asm Call with: BX = valid file handle Returns: if CF = 0, DX:AX = file size if CF = 1, AX = MS-DOS error code Uses: AX, DX, CF Example: include asm.inc extrn fsize:proc .data filenam db 'ASMLIB.DOC',0 ; ASCIIZ filename .code . . . lea dx,filenam ; point to filename mov ax,3D00h ; MS-DOS open file function, read-only int 21h jc oops ; jump to error control ; else no problem - continue mov bx,ax ; file handle in BX call fsize 같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같같� QFNAME: qualifies a filename Source: qfname.asm Call with: DS:[BX] pointing to a filename; the filename may contain drive specification and/or complete or partial path name. Drive specification and path name not required. Returns: DS:[SI] pointing to the full DRIVESPEC:\PATH\FILENAME CX = length of full filename Note that DS:[SI] points to QFName's buffer space; the next call to QFName will return a new filename at the same address. Uses: SI, CX, flags Example: include asm.inc .data docs db '*.doc',0 ; search for .DOC files in current directory .code ; program fragment assumes DS:@data . . . lea bx,docs call qfname