درخواست سورس جهت بدست آوردن Crc فایل

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با تشکر

CRC_CALC_Unit

نقل قول:

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unit Crc2;
interface
uses wintypes,winprocs,sysutils,classes;
{
Author: Jeff Ewing [ برای مشاهده لینک ، با نام کاربری خود وارد شوید یا ثبت نام کنید ]
this unit depends on Value OverFlow to calculate Checksums. Be sure
to disable overflow checking $Q- Otherwise you will have reported errors
on iterations that overflow (alot of EM!)}

{ GIVING CREDIT WHERE ITS DUE....
This code was adapted from C++ Source listings contained in
PRACTICAL ALGORITHMS FOR PROGRAMMERS
(Addison Wesley ISBN: 0-201-63208-X)
by Andrew Binstock & John Rex

CRC-CCITT: Used with XMODEM-CRC protocol and IBM's early SDLC/HDLC protocols.
CRC-16: Quick and Samll
CRC-32: More accurate
}

{ ******* USE THESE CALLS**********
These are the functions that you can use in YOUR code. The rest of this unit
is really an exercise in resource handling on my part. I wanted to use this unit
in main stream programs, but in the prev release all CRC data was stored in
const arrays that hung around in memory. This unit overcomes that problem by
loading the arrays at run time from resources... on demand.. and freeing them on
destroy.
******* USE THESE CALLS**********}

Function GetCRC32ForFile(Const Filename:String):LongInt;
Function GetCRC16ForFile(Const Filename:String):Word;
Function GetCCITTForFile(Const Filename:String):Word;
{ this line adds the data file rcdata.res to your project, NOTE THAT IF
this file is not found you will not run
vvvvvvvvvvvvvvv}
{$R crcdata.res}


type TCRCType=(crcCCITT,crc16,crc32);
{ Base class for Resource loading CRCTaable class}
type CRCData=class(Tobject)
private
RcId:Integer; { the integer id of the resource}
RcSize:Word; { The total size to alloc for storage in array }
RcIsWord:Boolean; { Is this resource word based on lingint based }
RcData:Pointer; { The actual data read from resource }
RcCount:Integer; { the Array[XX] number non zero based }
protected
function GetValue32(Index:Integer):LongInt; { get a long int from array}
function GetValue16(Index:Integer):Word; { get a word from array }

public
property Values32 [index:integer]:Longint read GetValue32;
property Values16 [index:integer]:Word read GetValue16;

constructor create(CRCTYPE:TCrcType);virtual;
destructor destroy;override;
end;

type TCRCCCITT=class(CRCData)
public
{ We override this property so we can make it look like an array
to the code}
property Values[index:integer]:Word read GetValue16 ;default;
constructor create;
end;

type TCRC16=class(CRCData)
public
{ We override this property so we can make it look like an array
to the code}
property Values[index:integer]:Word read GetValue16 ;default;
constructor create;
end;

type TCRC32=class(CRCData)
public
{ We override this property so we can make it look like an array
to the code}
property Values[index:integer]:LongINt read GetValue32 ;default;
constructor create;
end;


implementation

constructor TCrc16.create;
begin
inherited create(crc16);
end;
constructor TCrc32.create;
begin
inherited create(crc32);
end;
constructor TCrcCCITT.create;
begin
inherited create(crcCCITT);
end;

procedure CopyResToDst(Buff:Pointer;Size:Word;RCID:Integer);
{ This function copies a global resource memory block to a buffer pointed
to by Buff.}
Var
P:Pointer;
RHandle:Thandle;
DHandle:Thandle;
begin
{ 1st get a handle to the resource if 0 then not found. Be sure to
add the ->$R rcdata.res<- to your project}
Rhandle:=FindResource(Hinstance,makeintresource(RC ID),RT_RCDATA);
if RHandle<> 0 then
begin
{ next we have to actually load the resource (not the data.. yet.}
Dhandle:=LoadResource(Hinstance,Rhandle);
if Dhandle <> 0 then
begin
try
{ if we got it then lock (for windows to load it to a global buffer
that will be pointed to by P}
P:=LockResource(Dhandle);
{ yes, you could just use this global pointer as the
buffer, but I was too lazy to do that tonight...}
move(P^,buff^,Size);
finally
{ since we now have a copy of it in ram let the resource go}
FreeResource(Dhandle);
end;
end;
end;
end;

constructor CRCData.create(CRCTYPE:TCrcType);
begin
inherited create;
RcCount:=0;
RcData:=nil;
RcIsWord:=True;
RcSize:=0;

case CRCType of
crcCCITT: begin
RcIsWord:=True; { Rc values array is Word sized}
RcCount:=254; { there are 254 items in the resource}
RcSize:=(RcCount+1)*SizeOf(word); { array is 0 based so add 1}
RcId:=1;
end;
crc16: begin
RcIsWord:=True; { Rc values array is Word sized}
RcCount:=15; { there are 254 items in the resource}
RcSize:=(RcCount+1)*SizeOf(word); { array is 0 based so add 1}
RcId:=2;
Getmem(RcData,RcSize);
end;
crc32: begin
RcIsWord:=False; { Rc values array is Word sized}
RcCount:=254; { there are 254 items in the resource}
RcSize:=(RcCount+1)*SizeOf(LongINt); { array is 0 based so add 1}
RcId:=3;
end;
else
raise EComponentError.create('Unknown CRC tyype!');
end;

Getmem(RcData,RcSize);
CopyResToDst(RcData,RcSize,RCID);
end;

destructor CRCData.destroy;
begin
if RcData<> nil then
begin
if RcIsWord then
Freemem(RcData,(RcCount+1)* SizeOf(word))
else
Freemem(RcData,(RcCount+1)* SizeOf(LongINt));
end;
inherited destroy;
end;

function CRCData.GetValue32(Index:Integer):LongInt;
type AlArray=array[0..255] of LongInt;
begin
result:=0;
if RcisWord then exit; { avoid returning bogus data}
if ((Index > -1) and (Index < RcCount+1)) then
begin
Result:= AlArray(RcData^)[Index];
end
else
{ didnt raise here since its called so many times}
result:=0;

end;
function CRCData.GetValue16(Index:Integer):Word;
type AWArray=array[0..255] of Word;
begin
Result:=0;
if Not RcisWord then exit; { avoid returning bogus data}
if ((Index > -1) and (Index < RcCount+1)) then
begin
Result:= AWArray(RcData^)[Index];
end
else
{ didnt raise here since its called so many times}
result:=0;
end;


{//////////////////////////////////////////////////////////////////////////////}
Function GetCCITTForFile(Const Filename:String):Word;
Const ReadBufSize=32766;
Var
CCItTable:TCRCCCitt;
F:TfileStream;
Buff:Pointer;
Bread:Word;
{//////////////////////////////////////////////////////////////////////////////}
Function CalculateCCIT(Start:Integer;const Buff:Pchar;BuffSz:Integer):Word;
Var
Count:Integer;
Total:Word;
R1:Integer;
begin
{ Start : Starting CRC value should be 0 if this is the first pass
OR if a multip-pass calculation the last result from this function.
Buff : The buffer to Calculate the CRC for.
Buffsz : The size of the buffer;
}
Count:=-1;
Total:=Start;
while Count < BuffSz do
begin
{ Advance to Next Byte}
Inc(Count);
Total:= (Total SHL 8) XOR CCitTable[Total SHR 8] XOR ORD(buff[Count]);
End;
Result:=Total;
End;
{//////////////////////////////////////////////////////////////////////////////}
begin
if Not(FileExists(Filename)) then
Raise EFOpenError.Create('Cant open file:'+Filename);
CCitTable:=TCRCCCitt.Create;
GetMem(Buff,ReadBufSize);
Try
F:=TfileStream.Create(Filename,0);
Try
Result:=$0;
repeat
Bread:=F.REad(Buff^,ReadBufSize);
If Bread > 0 then
Result:=CalculateCCIT(Result,Pchar(Buff),Bread);
Until Bread < ReadBufSize;
finally
F.Free;
End;
Finally
CCitTable.Free;
FreeMem(Buff,ReadBufSize);
End;
End;
{//////////////////////////////////////////////////////////////////////////////}

{//////////////////////////////////////////////////////////////////////////////}
Function GetCRC16ForFile(Const Filename:String):Word;
Const ReadBufSize=32766;
Var
Crc16Table:TCRC16;
F:TfileStream;
Buff:Pointer;
Bread:Word;
{//////////////////////////////////////////////////////////////////////////////}
Function CalculateCRC16(Start:Integer;const Buff:Pchar;BuffSz:Integer):Word;
Var
Count:Integer;
Total:Word;
R1:Integer;
begin
{ Start : Starting CRC value should be 0 if this is the first pass
OR if a multip-pass calculation the last result from this function.
Buff : The buffer to Calculate the CRC for.
Buffsz : The size of the buffer;
}
Count:=-1;
Total:=Start;
while Count < BuffSz do
begin
{ Advance to Next Byte}
Inc(Count);

{ Do the lower 4 bits}
R1:=Crc16Table[Total AND $0f];
Total:=(Total SHR 4) AND $0FFF;
Total:=Total XOR r1 XOR Crc16Table[ORD(Buff[Count]) AND $F];
{ Do th upper 4 Bits}
r1:=Crc16Table[Total AND $0f];
Total:=(total SHR 4) AND $0FFF;
Total:=Total XOR r1 XOR Crc16Table[((ORD(Buff[Count])SHR 4) AND $F)];
End;
Result:=Total;
End;
{//////////////////////////////////////////////////////////////////////////////}
begin
if Not(FileExists(Filename)) then
Raise EFOpenError.Create('Cant open file:'+Filename);
Crc16Table:=TCRC16.Create;
GetMem(Buff,ReadBufSize);
try
F:=TfileStream.Create(Filename,0);
Try
Result:=$0;
repeat
Bread:=F.REad(Buff^,ReadBufSize);
If Bread > 0 then
Result:=CalculateCRC16(REsult,Pchar(Buff),Bread);
Until Bread < ReadBufSize;
finally
F.Free;
End;
Finally
Crc16Table.Free;
FreeMem(Buff,ReadBufSize);
End;
End;
{//////////////////////////////////////////////////////////////////////////////}

{//////////////////////////////////////////////////////////////////////////////}
Function GetCRC32ForFile(Const Filename:String):LongInt;
Const ReadBufSize=32766;
Var
Crc32Table:TCRC32;
F:TfileStream;
Buff:Pointer;
Bread:LongINt;
{//////////////////////////////////////////////////////////////////////////////}
Function CalculateCRC32(Start:LongInt;const Buff:Pchar;BuffSz:Integer):LongInt;
var
T1,R1:LongInt;
Count:Integer;
Loop:Integer;
Begin
{ Start : Starting CRC value should be $FFFFFFFF if this is the first pass
OR if a multip-pass calculation the last result from this function.
Buff : The buffer to Calculate the CRC for.
Buffsz : The size of the buffer;
}

R1:=Start;
For Count:=0 to BuffSz-1 do
begin
T1:=(R1 XOR ORD(buff[Count])) AND $000000FF;
r1:=((R1 SHR 8) AND $00FFFFFF) XOR Crc32Table[T1];
End;
Result:=R1;
End;
{//////////////////////////////////////////////////////////////////////////////}
begin
if Not(FileExists(Filename)) then
Raise EFOpenError.Create('Cant open file:'+Filename);
GetMem(Buff,ReadBufSize);
Crc32Table:=TCRC32.create;
try
F:=TfileStream.Create(Filename,0);
Try
{ Pre-Condition the CRC to Trap Dup leading 0 values on
buffer (if needed)}
Result:=$FFFFFFFF;
repeat
Bread:=F.REad(Buff^,ReadBufSize);
If Bread > 0 then
Result:=CalculateCRC32(REsult,Pchar(Buff),Bread);
Until Bread < ReadBufSize;
{ Post condition the buffer INVERT bits of the CRC}
Result:=NOT(Result);
finally
F.Free;
End;
Finally
CRC32Table.Free;
FreeMem(Buff,ReadBufSize);
End;
End;
{//////////////////////////////////////////////////////////////////////////////}






end.

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