111 lines
2.7 KiB
Plaintext
111 lines
2.7 KiB
Plaintext
{
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$Project$
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$Workfile$
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$Revision$
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$DateUTC$
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$Id$
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This file is part of the Indy (Internet Direct) project, and is offered
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under the dual-licensing agreement described on the Indy website.
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(http://www.indyproject.org/)
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Copyright:
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(c) 1993-2005, Chad Z. Hower and the Indy Pit Crew. All rights reserved.
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}
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{
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$Log$
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}
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unit IdStreamNET;
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interface
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uses
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Classes,
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IdGlobal;
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type
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TIdStreamHelperNET = class
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public
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class function ReadBytes(
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AStream: TStream;
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var VBytes: TIdBytes;
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ACount: Integer = -1;
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AOffset: Integer = 0): Integer; static;
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class function Write(
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const AStream: TStream;
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const ABytes: TIdBytes;
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const ACount: Integer = -1;
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const AOffset: Integer = 0): Integer; static;
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class function Seek(
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const AStream: TStream;
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const AOffset: TIdStreamSize;
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const AOrigin: TSeekOrigin) : TIdStreamSize; static;
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end;
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implementation
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// RLebeau: must use a 'var' and not an 'out' for the VBytes parameter,
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// or else any preallocated buffer the caller passes in will get wiped out!
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class function TIdStreamHelperNET.ReadBytes(AStream: TStream; var VBytes: TIdBytes;
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ACount, AOffset: Integer): Integer;
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var
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LActual: Integer;
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begin
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Assert(AStream<>nil);
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Result := 0;
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if VBytes = nil then begin
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SetLength(VBytes, 0);
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end;
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//check that offset<length(buffer)? offset+count?
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//is there a need for this to be called with an offset into a nil buffer?
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LActual := ACount;
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if LActual < 0 then begin
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LActual := AStream.Size - AStream.Position;
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end;
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//this prevents eg reading 0 bytes at Offset=10 from allocating memory
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if LActual = 0 then begin
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Exit;
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end;
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if Length(VBytes) < (AOffset+LActual) then begin
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SetLength(VBytes, AOffset+LActual);
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end;
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Assert(VBytes<>nil);
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Result := AStream.Read(VBytes, AOffset, LActual);
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end;
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class function TIdStreamHelperNET.Write(const AStream: TStream;
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const ABytes: TIdBytes; const ACount: Integer; const AOffset: Integer): Integer;
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var
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LActual: Integer;
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begin
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Result := 0;
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Assert(AStream<>nil);
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//should we raise assert instead of this nil check?
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if ABytes <> nil then
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begin
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LActual := IndyLength(ABytes, ACount, AOffset);
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if LActual > 0 then
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begin
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// RLebeau: Write raises an exception if the buffer can't be written in full
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AStream.Write(ABytes, AOffset, LActual);
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Result := LActual;
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end;
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end;
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end;
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class function TIdStreamHelperNET.Seek(const AStream: TStream; const AOffset: TIdStreamSize;
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const AOrigin: TSeekOrigin): TIdStreamSize;
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begin
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Result := AStream.Seek(AOffset, AOrigin);
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end;
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end.
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