[SOLVED] Improvement of procedure TSHA512Base.Update
lazarus / 64-FPC development

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lagprogramming · 2023-09-09 07:16

packages/fcl-hash/src/fpsha512.pp has
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TSHA512Base.Update(PBuf: PByte; Size: UInt32);var  Len: UInt32;begin 
Inc(TotalLength, Int64(UInt32(Size)) * 8);  while Size > 0 do  begin 
 Len:=Sizeof(Buffer)-Index;    if Len <= UInt32(Size) then    begin  
  Move(PBuf^, Buffer[Index], Len);      Dec(Size, Len);      Inc(PBuf,
Len);      Compress;      Self.Index := 0;    end else    begin     
Move(PBuf^, Buffer[Index], Size);      Inc(Self.Index, Size);     
Size := 0;    end;  end;end;In order to exit the loop the original
code sets a zero value to Size. The attached patch changes the line
"Size := 0;" with "Break;". In addition to increased readability, the
CPU will avoid a failed prediction of the "Size > 0" condition.

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AlexTP · 2023-09-09 07:38

Posted to https://gitlab.com/freepascal.org/fpc/source/-/issues/40435

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abouchez · 2023-09-09 08:46

Sounds like a non-improvement to me.

Performance would be identical for sure, and readability not enhanced
to my taste.

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AlexTP · 2023-09-09 10:13

Anyway, I keep posting suggestions from 'lagprogramming'. He does
minor work, but useful.