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own Rng function #9

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Merged
merged 1 commit into from
Mar 5, 2024
Merged

own Rng function #9

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21 changes: 17 additions & 4 deletions generator/Common/generate.common.pas
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ TGenerator = class(TObject)
procedure BuildStationNames;
function GenerateProgressBar(APBPosition, APBMax, APBWIdth, AFileSize: Int64;
ATimeElapsed: TDateTime): String;
function Rng1brc(Range: longint): longint;
protected
public
constructor Create(AInputFile, AOutputFile: String; ALineCount: Int64);
Expand Down Expand Up @@ -158,6 +159,20 @@ function TGenerator.GenerateProgressBar(APBPosition, APBMax, APBWIdth, AFileSize
ATimeElapsed)]);
end;

function TGenerator.Rng1brc(Range: longint): longint;
const
state: Array [0..1] of DWord = (46668267, 7266);
var
s0, s1, s2: DWord;
begin
s0 := state[0];
s1 := state[1] xor s0;
s2 := RolDWord(s1 * 3, 5) * 7;
Result := longint(Int64(s2 * range) shr 32);
state[0] := s2;
state[1] := s0 xor (s1 shl 9);
end;

procedure TGenerator.Generate;
var
index, progressCount, progressBatch: Int64;
Expand Down Expand Up @@ -232,10 +247,8 @@ procedure TGenerator.Generate;
// Generate the file
for index := 1 to FLineCount do
begin
stationId := Random(stationsCount);
// This is all paweld magic:
// From here
randomTemp := Random(temperaturesCount);
stationId := Rng1brc(stationsCount);
randomTemp := Rng1brc(temperaturesCount);
Move(stationArray[stationId][1], chunkLine[chunkLen + 1],
LenStationArray[stationId]);
Inc(chunkLen, LenStationArray[stationId]);
Expand Down