;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2013. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;; ;;
;; GNU GENERAL PUBLIC LICENSE ;;
;; Version 2, June 1991 ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
get_next_byte:
; Load next byte from the packet, translating to cp866 if necessary
; At input esi = pointer to data, edx = limit of data
; Output is either (translated) byte in al with CF set or CF cleared.
mov eax, [encoding]
jmp [get_byte_table+eax*4]
get_byte_cp866:
cmp esi, edx
jae .nothing
lodsb
.nothing:
ret
get_byte_cp1251:
cmp esi, edx
jae .nothing
lodsb
cmp al, 0x80
jb @f
and eax, 0x7F
mov al, [cp1251_table+eax]
@@:
stc
.nothing:
ret
get_byte_utf8:
; UTF8 decoding is slightly complicated.
; One character can occupy one or more bytes.
; The boundary in packets theoretically can be anywhere in data,
; so this procedure keeps internal state between calls and handles
; one byte at a time, looping until character is read or packet is over.
; Globally, there are two distinct tasks: decode byte sequence to unicode char
; and convert this unicode char to our base encoding (that is cp866).
; 1. Check that there are data.
cmp esi, edx
jae .nothing
; 2. Load byte.
lodsb
movzx ecx, al
; 3. Bytes in an UTF8 sequence can be of any of three types.
; If most significant bit is cleared, sequence is one byte and usual ASCII char.
; First byte of a sequence must be 11xxxxxx, other bytes are 10yyyyyy.
and al, 0xC0
jns .single_byte
jp .first_byte
; 4. This byte is not first in UTF8 sequence.
; 4a. Check that the sequence was started. If no, it is invalid byte
; and we simply ignore it.
cmp [utf8_bytes_rest], 0
jz get_byte_utf8
; 4b. Otherwise, it is really next byte and it gives some more bits of char.
mov eax, [utf8_char]
shl eax, 6
lea eax, [eax+ecx-0x80]
; 4c. Decrement number of bytes rest in the sequence.
; If it goes to zero, character is read, so return it.
dec [utf8_bytes_rest]
jz .got_char
mov [utf8_char], eax
jmp get_byte_utf8
; 5. If the byte is first in UTF8 sequence, calculate the number of leading 1s
; - it equals total number of bytes in the sequence; some other bits rest for
; leading bits in the character.
.first_byte:
mov eax, -1
@@:
inc eax
add cl, cl
js @b
mov [utf8_bytes_rest], eax
xchg eax, ecx
inc ecx
shr al, cl
mov [utf8_char], eax
jmp get_byte_utf8
; 6. If the byte is ASCII char, it is the character.
.single_byte:
xchg eax, ecx
.got_char:
; We got the character, now abandon a possible sequence in progress.
and [utf8_bytes_rest], 0
; Now second task. The unicode character is in eax, and now we shall convert it
; to cp866.
cmp eax, 0x80
jb .done
; 0x410-0x43F -> 0x80-0xAF, 0x440-0x44F -> 0xE0-0xEF, 0x401 -> 0xF0, 0x451 -> 0xF1
cmp eax, 0x401
jz .YO
cmp eax, 0x451
jz .yo
cmp eax, 0x410
jb .unrecognized
cmp eax, 0x440
jb .part1
cmp eax, 0x450
jae .unrecognized
sub al, (0x40-0xE0) and 0xFF
ret
.part1:
sub al, 0x10-0x80
.nothing:
.done:
ret
.unrecognized:
mov al, '?'
stc
ret
.YO:
mov al, 0xF0
stc
ret
.yo:
mov al, 0xF1
stc
ret
recode_to_cp866:
rep movsb
ret
recode_to_cp1251:
xor eax, eax
jecxz .nothing
.loop:
lodsb
cmp al,0x80
jb @f
mov al, [cp866_table-0x80+eax]
@@: stosb
loop .loop
.nothing:
ret
recode_to_utf8:
jecxz .nothing
.loop:
lodsb
cmp al, 0x80
jb .single_byte
and eax, 0x7F
mov ax, [utf8_table+eax*2]
stosw
loop .loop
ret
.single_byte:
stosb
loop .loop
.nothing:
ret
recode:
mov eax, [encoding]
jmp [recode_proc+eax*4]
encoding dd UTF8
recode_proc dd recode_to_cp866, recode_to_cp1251, recode_to_utf8
get_byte_table dd get_byte_cp866, get_byte_cp1251, get_byte_utf8
cp1251_table:
db '?','?','?','?','?','?','?','?' , '?','?','?','?','?','?','?','?' ; 8
db '?','?','?','?','?',$F9,'?','?' , '?','?','?','?','?','?','?','?' ; 9
db '?',$F6,$F7,'?',$FD,'?','?','?' , $F0,'?',$F2,'?','?','?','?',$F4 ; A
db $F8,'?','?','?','?','?','?',$FA , $F1,$FC,$F3,'?','?','?','?',$F5 ; B
db $80,$81,$82,$83,$84,$85,$86,$87 , $88,$89,$8A,$8B,$8C,$8D,$8E,$8F ; C
db $90,$91,$92,$93,$94,$95,$96,$97 , $98,$99,$9A,$9B,$9C,$9D,$9E,$9F ; D
db $A0,$A1,$A2,$A3,$A4,$A5,$A6,$A7 , $A8,$A9,$AA,$AB,$AC,$AD,$AE,$AF ; E
db $E0,$E1,$E2,$E3,$E4,$E5,$E6,$E7 , $E8,$E9,$EA,$EB,$EC,$ED,$EE,$EF ; F
; 0 1 2 3 4 5 6 7 8 9 A B C D E F
utf8_table:
times 80h dw 0x98C3 ; default placeholder
; 0x80-0xAF -> 0x90D0-0xBFD0
repeat 0x30
store byte 0xD0 at utf8_table+2*(%-1)
store byte 0x90+%-1 at utf8_table+2*%-1
end repeat
; 0xE0-0xEF -> 0x80D1-0x8FD1
repeat 0x10
store byte 0xD1 at utf8_table+2*(0xE0-0x80+%-1)
store byte 0x80+%-1 at utf8_table+2*(0xE0-0x80+%)-1
end repeat
; 0xF0 -> 0x81D0, 0xF1 -> 0x91D1
store dword 0x91D181D0 at utf8_table+2*(0xF0-0x80)
cp866_table:
db $C0,$C1,$C2,$C3,$C4,$C5,$C6,$C7 , $C8,$C9,$CA,$CB,$CC,$CD,$CE,$CF ; 8
db $D0,$D1,$D2,$D3,$D4,$D5,$D6,$D7 , $D8,$D9,$DA,$DB,$DC,$DD,$DE,$DF ; 9
db $E0,$E1,$E2,$E3,$E4,$E5,$E6,$E7 , $E8,$E9,$EA,$EB,$EC,$ED,$EE,$EF ; A
db '?','?','?','?','?','?','?','?' , '?','?','?','?','?','?','?','?' ; B
db '?','?','?','?','?','?','?','?' , '?','?','?','?','?','?','?','?' ; C
db '?','?','?','?','?','?','?','?' , '?','?','?','?','?','?','?','?' ; D
db $F0,$F1,$F2,$F3,$F4,$F5,$F6,$F7 , $F8,$F9,$FA,$FB,$FC,$FD,$FE,$FF ; E
db $A8,$B8,$AA,$BA,$AF,$BF,$A1,$A2 , $B0,$95,$B7,'?',$B9,$A4,'?','?' ; F
; 0 1 2 3 4 5 6 7 8 9 A B C D E F