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+ added methods for calculating and verifying the omf record checksum and

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properties for accessing it

git-svn-id: trunk@30345 -
This commit is contained in:
nickysn 2015-03-28 01:55:03 +00:00
parent 359eaa4152
commit 131422b594
1 changed files with 46 additions and 0 deletions
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46
compiler/omfbase.pas
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@ -77,8 +77,10 @@ interface
TOmfRawRecord = class
private
function GetChecksumByte: Byte;
function GetRecordLength: Word;
function GetRecordType: Byte;
procedure SetChecksumByte(AValue: Byte);
procedure SetRecordLength(AValue: Word);
procedure SetRecordType(AValue: Byte);
public
@ -86,6 +88,10 @@ interface
property RecordType: Byte read GetRecordType write SetRecordType;
property RecordLength: Word read GetRecordLength write SetRecordLength;
procedure CalculateChecksumByte;
function VerifyChecksumByte: boolean;
property ChecksumByte: Byte read GetChecksumByte write SetChecksumByte;
procedure ReadFrom(aReader: TObjectReader);
procedure WriteTo(aWriter: TObjectWriter);
end;
@ -115,6 +121,46 @@ implementation
RawData[-1]:=Byte(AValue shr 8);
end;
function TOmfRawRecord.GetChecksumByte: Byte;
begin
if RecordLength>0 then
Result:=RawData[RecordLength-1]
else
Result:=0;
end;
procedure TOmfRawRecord.SetChecksumByte(AValue: Byte);
begin
if RecordLength>0 then
RawData[RecordLength-1]:=AValue;
end;
procedure TOmfRawRecord.CalculateChecksumByte;
var
I: Integer;
b: Byte;
begin
b:=0;
for I:=-3 to RecordLength-2 do
b:=byte(b+RawData[I]);
SetChecksumByte($100-b);
end;
function TOmfRawRecord.VerifyChecksumByte: boolean;
var
I: Integer;
b: Byte;
begin
{ according to the OMF spec, some tools always write a 0 rather than
computing the checksum, so it should also be accepted as correct }
if ChecksumByte=0 then
exit(true);
b:=0;
for I:=-3 to RecordLength-1 do
b:=byte(b+RawData[I]);
Result:=(b=0);
end;
procedure TOmfRawRecord.ReadFrom(aReader: TObjectReader);
begin
aReader.read(RawData, 3);