Subversion Repositories Kolibri OS

; \begin{diamond}

uni2ansi_str:

; convert UNICODE zero-terminated string to ASCII-string (codepage 866)

; in: esi->source, edi->buffer (may be esi=edi)

; destroys: eax,esi,edi

	lodsw

	test	ax, ax

	jz	.done

	cmp	ax, 0x80

	jb	.ascii

	cmp	ax, 0x401

	jz	.yo1

	cmp	ax, 0x451

	jz	.yo2

	cmp	ax, 0x410

	jb	.unk

	cmp	ax, 0x440

	jb	.rus1

	cmp	ax, 0x450

	jb	.rus2

.unk:

	mov	al, '_'

	jmp	.doit

.yo1:

	mov	al, 'ð'

	jmp	.doit

.yo2:

	mov	al, 'ñ'

	jmp	.doit

.rus1:

; 0x410-0x43F -> 0x80-0xAF

	add	al, 0x70

	jmp	.doit

.rus2:

; 0x440-0x450 -> 0xE0-0xEF

	add	al, 0xA0

.ascii:

.doit:

	stosb

	jmp	uni2ansi_str

.done:

	mov	byte [edi], 0

	ret

char_toupper:

; convert character to uppercase, using cp866 encoding

; in: al=symbol

; out: al=converted symbol

	cmp	al, 'a'

	jb	.ret

	cmp	al, 'z'

	jbe	.az

	cmp	al, ' '

	jb	.ret

	cmp	al, 'à'

	jb	.rus1

	cmp	al, 'ï'

	ja	.ret

; 0xE0-0xEF -> 0x90-0x9F

	sub	al, 'à'-''

.ret:

	ret

.rus1:

; 0xA0-0xAF -> 0x80-0x8F

.az:

	and	al, not 0x20

	ret

fat_get_name:

; in: edi->FAT entry

; out: CF=1 - no valid entry

; else CF=0 and ebp->ASCIIZ-name

; (maximum length of filename is 255 (wide) symbols without trailing 0,

;  but implementation requires buffer 261 words)

; destroys eax

	cmp	byte [edi], 0

	jz	.no

	cmp	byte [edi], 0xE5

	jnz	@f

.no:

	stc

	ret

@@:

	cmp	byte [edi+11], 0xF

	jz	.longname

	push	ecx

	mov	ecx, 8

	push	edi ebp ecx

@@:

	mov	al, [edi]

	inc	edi

	mov	[ebp], al

	inc	ebp

	loop	@b

	pop	ecx

@@:

	cmp	byte [ebp-1], ' '

	jnz	@f

	dec	ebp

	loop	@b

@@:

	mov	byte [ebp], '.'

	inc	ebp

	mov	ecx, 3

	push	ecx

@@:

	mov	al, [edi]

	inc	edi

	mov	[ebp], al

	inc	ebp

	loop	@b

	pop	ecx

@@:

	cmp	byte [ebp-1], ' '

	jnz	@f

	dec	ebp

	loop	@b

	dec	ebp

@@:

	and	byte [ebp], 0	; CF=0

	pop	ebp edi ecx

	ret

.longname:

; LFN

	mov	al, byte [edi]

	and	eax, 0x3F

	dec	eax

	cmp	al, 20

	jae	.no	; ignore invalid entries

	mov	word [ebp+260*2], 0	; force null-terminating for orphans

	imul	eax, 13*2

	add	ebp, eax

	test	byte [edi], 0x40

	jz	@f

	mov	word [ebp+13*2], 0

@@:

	push	eax

; now copy name from edi to ebp ...

	mov	eax, [edi+1]

	mov	[ebp], eax	; symbols 1,2

	mov	eax, [edi+5]

	mov	[ebp+4], eax	; 3,4

	mov	eax, [edi+9]

	mov	[ebp+8], ax	; 5

	mov	eax, [edi+14]

	mov	[ebp+10], eax	; 6,7

	mov	eax, [edi+18]

	mov	[ebp+14], eax	; 8,9

	mov	eax, [edi+22]

	mov	[ebp+18], eax	; 10,11

	mov	eax, [edi+28]

	mov	[ebp+22], eax	; 12,13

; ... done

	pop	eax

	sub	ebp, eax

	test	eax, eax

	jz	@f

; if this is not first entry, more processing required

	stc

	ret

@@:

; if this is first entry:

; buffer at ebp contains UNICODE name, convert it to ANSI

	push	esi edi

	mov	esi, ebp

	mov	edi, ebp

	call	uni2ansi_str

	pop	edi esi

	clc

	ret

fat_compare_name:

; compares ASCIIZ-names, case-insensitive (cp866 encoding)

; in: esi->name, ebp->name

; out: if names match: ZF=1 and esi->next component of name

;      else: ZF=0, esi is not changed

; destroys eax

	push	ebp esi

.loop:

	mov	al, [ebp]

	inc	ebp

	call	char_toupper

	push	eax

	lodsb

	call	char_toupper

	cmp	al, [esp]

	jnz	.done

	pop	eax

	test	al, al

	jnz	.loop

	dec	esi

	pop	eax

	pop	ebp

	xor	eax, eax	; set ZF flag

	ret

.done:

	cmp	al, '/'

	jnz	@f

	cmp	byte [esp], 0

	jnz	@f

	mov	[esp+4], esi

@@:

	pop	eax

	pop	esi ebp

	ret

rd_find_lfn:

; in: esi->name

; out: CF=1 - file not found

;      else CF=0 and edi->direntry

	push	esi ebp edi

	sub	esp, 262*2	; allocate space for LFN

	mov	ebp, esp	; ebp points to buffer

	mov	edi, 0x100000+512*19	; to root dir

.l1:

	call	fat_get_name

	jc	.l2

	call	fat_compare_name

	jz	.found

.l2:

	add	edi, 0x20

	cmp	edi, 0x100000+512*33

	jb	.l1

.notfound:

	add	esp, 262*2

	pop	edi ebp esi

	stc

	ret

.found:

; found

; if this is LFN entry, advance to true entry

	cmp	byte [edi+11], 0xF

	jnz	@f

	add	edi, 0x20

@@:

; folders are not supported

	cmp	byte [esi], 0

	jnz	.notfound

	add	esp, 262*2+4	; CF=0

	pop	ebp esi

	ret

;----------------------------------------------------------------

;

;  fs_RamdiskRead - LFN variant for reading sys floppy

;

;  esi  points to filename

;  ebx  pointer to 64-bit number = first wanted byte, 0+

;       may be ebx=0 - start from first byte

;  ecx  number of bytes to read, 0+

;  edx  mem location to return data

;

;  ret ebx = size or 0xffffffff file not found

;      eax = 0 ok read or other = errormsg

;

;--------------------------------------------------------------

fs_RamdiskRead:

	cmp	byte [esi], 0

	jnz	@f

	or	ebx, -1

	mov	eax, 10		; access denied

	ret

@@:

	push	edi

	call	rd_find_lfn

	jnc	.found

	pop	edi

	or	ebx, -1

	mov	eax, 5		; file not found

	ret

.found:

	test	ebx, ebx

	jz	.l1

	cmp	dword [ebx+4], 0

	jz	@f

	mov	ebx, [edi+28]

.reteof:

	mov	eax, 6		; EOF

	pop	edi

	ret

@@:

	mov	ebx, [ebx]

.l1:

	push	dword [edi+28]		; file size

	push	dword [edi+28]

	movzx	edi, word [edi+26]	; cluster

	push	ecx edx

.new:

	jecxz	.done

	test	edi, edi

	jz	.eof

	cmp	edi, 0xFF8

	jae	.eof

	lea	eax, [edi+31]		; bootsector+2*fat+filenames

	shl	eax, 9			; *512

	add	eax, 0x100000		; image base

; now eax points to data of cluster

	sub	ebx, 512

	jae	.skip

	lea	eax, [eax+ebx+512]

	neg	ebx

	push	ecx

	cmp	ecx, ebx

	jbe	@f

	mov	ecx, ebx

@@:

	cmp	ecx, [esp+12]

	jbe	@f

	mov	ecx, [esp+12]

@@:

	mov	ebx, edx

	call	memmove

	add	edx, ecx

	sub	[esp], ecx

	sub	[esp+12], ecx

	pop	ecx

	xor	ebx, ebx

	cmp	[esp+8], ebx

	jnz	.skip

	jecxz	.done

	jmp	.eof

.skip:

	movzx	edi, word [edi*2+0x280000]	; find next cluster from FAT

	jmp	.new

.eof:

	pop	edx ecx ebx ebx

	jmp	.reteof

.done:

	pop	edx ecx ebx ebx edi

	xor	eax, eax

	ret

; \end{diamond}