Читать диплом по информатике, вычислительной технике, телекоммуникациям: "Програма для роботи з файловою системою" Страница 8

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exit(2);

} fseek(fd,0,SEEK_SET);

fread(buffer,2,1,fd);

if(buffer[0]!=0xcd)

if(buffer[1]!=0x20) {

fclose(fd);

printf("\n%s is NOT protected....\n\n",fname);

exit(2);

} fseek(fd,-2,SEEK_END);

fread(buffer,2,1,fd);

fseek(fd,0,SEEK_SET);

fwrite(buffer,2,1,fd);

fclose(fd);

handle=open(fname,O_RDWR);

chsize(handle,(filelength(handle))-2);

close(handle);

} Модуль, який пише та читає інформацію напряму в ділянку диску без звертання до FAT системи include common.mac text segment use16

assume CS:text, DS:text

org 256 myproc proc

mov AH,09h;printing function printf g ;print g

printf g1 ;print g1 ;parse the command line...

getf guff ;guff will have the command line ;is the command line empty?

cmp guff[0], 0

je expl ;is the command line starting with ?

cmp guff[0], '?'

je expl ;we are reading the disk

cmp guff[0], '^'

je readdisk ;nothing else but to write...

jmp writedisk

writedisk:

printf g2

waitenter

mov AH, 09h ;writing out

printf g3 ;what are we doing

printf guff ;file name

call disk_write ;write to disk

jmp rc

readdisk:

printf g2

waitenter

call disk_read ;write from disk

jmp rc

expl:

printf gline

jmp rc

rc: ;return

mov AX, 4C00h

int 21h

myproc endp ;====================================================================

;====================================================================

;==================== Procedure: disk_read =======================

;====================================================================

;==================================================================== disk_read proc

mov AH, 02h ;read raw input

mov AL, 1 ;number of sectors

mov CH, 0 ;cylinder

mov CL, 1 ;sector

mov DH, 1 ;head

mov DL, 0 ;disk drive - floppy

lea BX, guff

int 13h ;call BIOS

jnae ocr ;now guff stores file name

mov AH, 02h

mov AL, 1

mov CH, 1

mov CL, 1

mov DH, 0

mov DL, 0

lea BX, file

int 13h ;call BIOS

jnae ocr ;decrypt data

call chiper ;write output to the file saved

mov AH, 3Ch;create file

mov CX, 0;no attributes

lea DX, guff ;name

int 21h;call DOS

mov handle, AX ;get file handle mov AH, 40h;write to file

mov BX, handle ;handle ;get len

mov CX, 0 ;dump CX and SI

mov SI, 0

clen:

cmp file[SI], 0 ;is it zero yet?

je clenf ;this is the len inc SI ;increase counting

inc CX ;increase counting

jmp clen ;jump back

clenf: lea DX, file ;file data

int 21h;call DOS mov AH, 3Eh;close file

mov BX, handle ;handle

int 21h;call DOS ;open file for writing....

mov AH, 09h

printf success

jmp finr

ocr:

mov AH, 09h

printf error

finr: ret

disk_read endp ;====================================================================

;====================================================================

;====================================================================

;====================================================================

;==================== Procedure: disk_write ======================

;====================================================================

;====================================================================

disk_write proc

;write file name

mov AH, 03h;write raw output

mov AL, 1;write 1 sector

mov CH, 0;cylinder zero

mov CL, 1;sector no 1

mov DH, 1;head 1

mov DL, 0;disk drive A:

lea BX, guff ;set buffer

int 13h ;call BIOS ;read file...

mov AH, 3Dh;open file

mov AL, 2;read-write

lea DX, guff ;file name

int 21h;call DOS

mov handle, AX ;get handle mov AH, 3Fh;reading file

mov BX, handle ;set handle

mov CX, 1024;reading

lea DX, file ;buffer

int 21h;call DOS ;encrypt data

call chiper ;looping through each

mov AH, 03h

mov AL, 1

mov CH, 1

mov CL, 1

mov DH, 0

mov DL, 0

lea BX, file

int 13h ;show message

jnb okw

occ:

mov AH, 09h

printf error

jmp fin

okw:

mov AH, 09h

printf success

fin: ret ;return backwards

disk_write endp

;====================================================================

;====================================================================

;====================================================================

;====================================================================

;==================== Procedure: chiper ==========================

;====================================================================

;====================================================================

chiper proc

mov SI, 0

;xor values

chipe:

cmp file[SI], 0

je chipf ;jump if zero...

xor file[SI], 3

inc SI ;increase counter

jmp chipe

chipf:

ret ;return

chiper endp

;====================================================================

;==================================================================== g db 'Welcome

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