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// This file is part of Adlib Tracker II (AT2).
//
// AT2 is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// AT2 is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with AT2. If not, see <http://www.gnu.org/licenses/>.
unit ParserIO;
{$S-,Q-,R-,V-,B-,X+}
{$PACKRECORDS 1}
interface
function SensitiveScan(var buf; skip,size: Longint; str: String): Longint;
function Update16(var buf; size: Longint; crc: Word): Word;
function Update32(var buf; size: Longint; crc: Longint): Longint;
implementation
function SensitiveScan(var buf; skip,size: Longint; str: String): Longint;
var
result: Longint;
begin
asm
mov edi,[buf]
add edi,skip
lea esi,[str]
mov ecx,size
sub ecx,skip
xor eax,eax
jecxz @@3
cld
lodsb
cmp al,1
jb @@5
ja @@1
lodsb
repne scasb
jne @@3
jmp @@5
@@1: xor ah,ah
mov ebx,eax
dec ebx
mov edx,ecx
sub edx,eax
jb @@3
lodsb
add edx,2
@@2: dec edx
mov ecx,edx
repne scasb
jne @@3
mov edx,ecx
mov ecx,ebx
rep cmpsb
je @@4
sub ecx,ebx
add esi,ecx
add edi,ecx
inc edi
or edx,edx
jne @@2
@@3: xor eax,eax
jmp @@6
@@4: sub edi,ebx
@@5: mov eax,edi
sub eax,dword ptr [buf]
@@6: dec eax
mov result,eax
end;
SensitiveScan := result;
end;
var
CRC16_table: array[BYTE] of Word;
CRC32_table: array[BYTE] of Longint;
function Update16(var buf; size: Longint; crc: Word): Word;
var
result: Word;
begin
asm
mov esi,[buf]
lea edi,[CRC16_table]
mov bx,crc
mov ecx,size
jecxz @@2
@@1: xor ax,ax
lodsb
mov dl,bh
xor dh,dh
xor bh,bh
xor bx,ax
and ebx,000000ffh
shl ebx,1
mov bx,[edi+ebx]
xor bx,dx
loop @@1
@@2: mov ax,bx
mov result,ax
end;
Update16 := result;
end;
function Update32(var buf; size: Longint; crc: Longint): Longint;
var
result: Longint;
begin
asm
mov esi,[buf]
lea edi,[CRC32_table]
mov ebx,crc
mov ecx,size
jecxz @@2
@@1: xor eax,eax
lodsb
xor ebx,eax
mov edx,ebx
and ebx,000000ffh
shl ebx,2
mov ebx,[edi+ebx]
shr edx,8
and edx,00ffffffh
xor ebx,edx
loop @@1
@@2: mov eax,ebx
mov result,eax
end;
Update32 := result;
end;
procedure make_table_16bit;
var
crc: Word;
n,index: Byte;
begin
For index := 0 to 255 do
begin
crc := index;
For n := 1 to 8 do
If Odd(crc) then crc := crc SHR 1 XOR $0a001
else crc := crc SHR 1;
CRC16_table[index] := crc;
end;
end;
procedure make_table_32bit;
var
crc: Dword;
n,index: Byte;
begin
For index := 0 to 255 do
begin
crc := index;
For n := 1 to 8 do
If Odd(crc) then crc := crc SHR 1 XOR $0edb88320
else crc := crc SHR 1;
CRC32_table[index] := crc;
end;
end;
begin
make_table_16bit;
make_table_32bit;
end.
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