kolibrios-fun/programs/jpegview/trunk/filelib.asm

152 lines
2.5 KiB
NASM
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file_handler:
.position=0
.size=4
.bufer_block=8
.operation=12
.first_block=16
.n_blocks=20
.bufer=24
.work_area=28
.name=32
.st_size=32+128
open: ;esi=name_string
;retorna eax
pushad
push dword [work_area]
mov ecx,512 ;bufer
call malloc
push edi
mov ecx,file_handler.st_size
call mallocz
pop dword[edi+file_handler.bufer]
pop dword[edi+file_handler.work_area]
mov [esp+28],edi
mov ecx,100
add edi,file_handler.name
call movedata
mov edi,[esp+28]
mov byte[edi+file_handler.n_blocks],1
mov eax,58
lea ebx,[edi+file_handler.operation]
push edi
int 0x40
pop edi
test eax,eax
jnz close.b
mov [edi+file_handler.size],ebx
clc
popad
ret
close:
pushad
.b:
mov eax,[esp+28]
mov edi,[eax+file_handler.bufer]
call free
mov edi,eax
call free
popad
xor eax,eax
ret
read: ;(f,bufer,nbytes) eax,edi,ecx ncr
;retorna bytes leidos en ecx
pushad
mov edx,[eax+file_handler.size]
sub edx,[eax+file_handler.position]
cmp edx,ecx
jnc .nb_ok
mov ecx,edx
mov [esp+24],edx
.nb_ok:
jecxz .final
mov byte[eax+file_handler.operation],0
test dword[eax+file_handler.position],511
jz .l1
call .bufer
.l1:
mov edx,ecx
shr edx,9
jz .l2
mov [eax+file_handler.n_blocks],edx
mov edx,[eax+file_handler.position]
shr edx,9
mov [eax+file_handler.first_block],edx
xchg edi,[eax+file_handler.bufer]
pushad
lea ebx,[eax+file_handler.operation]
mov eax,58
int 40h
cmp eax,0ffffff00h
jnc .error
popad
xchg edi,[eax+file_handler.bufer]
mov edx,ecx
and edx,0fffffe00h
add [eax+file_handler.position],edx
add edi,edx
.l2:
and ecx,511
jz .final
call .bufer
.final:
popad
ret
.bufer:
pushad
mov ebx,[eax+file_handler.position]
shr ebx,9
cmp ebx,[eax+file_handler.bufer_block]
je .l3
mov [eax+file_handler.first_block],ebx
mov [eax+file_handler.bufer_block],ebx
mov dword[eax+file_handler.n_blocks],1
lea ebx,[eax+file_handler.operation]
mov eax,58
int 40h
cmp eax,0ffffff00h
jnc .error
.l3:
mov eax,[esp+28]
mov edx,[eax+file_handler.position]
mov esi,[eax+file_handler.bufer]
and edx,511
add esi,edx
neg edx
add edx,512
cmp ecx,edx
jc .l4
mov ecx,edx
.l4:
add [eax+file_handler.position],ecx
sub [esp+24],ecx
pop edi
call movedata
push edi
popad
ret
.error:
popad
popad
xor ecx,ecx
stc
ret
ftell: mov edx,[eax+file_handler.position]
ret
lseek: ;eax=file edx=pos
mov [eax+file_handler.position],edx
ret
skip: ;eax=file edx=bytes to skip
add [eax+file_handler.position],edx
ret