--- a/hedgewars/uRandom.pas Sun Aug 06 20:58:05 2006 +0000
+++ b/hedgewars/uRandom.pas Mon Aug 07 12:08:43 2006 +0000
@@ -33,41 +33,46 @@
unit uRandom;
interface
-uses uSHA;
-procedure SetRandomParams(Seed: shortstring; FillBuf: shortstring);
+procedure SetRandomSeed(Seed: shortstring);
function GetRandom: real; overload;
function GetRandom(m: LongWord): LongWord; overload;
implementation
-var sc1, sc2: TSHA1Context;
- Fill: shortstring;
+const rndM = 2147483578;
+var cirbuf: array[0..63] of Longword;
+ n: byte;
-procedure SetRandomParams(Seed: shortstring; FillBuf: shortstring);
+function GetNext: Longword;
begin
-SHA1Init(sc1);
-SHA1Update(sc1, @Seed, Length(Seed)+1);
-Fill:= FillBuf
+n:= (n + 1) and $3F;
+cirbuf[n]:=
+ (cirbuf[(n + 40) and $3F] + {== n - 24 mod 64}
+ cirbuf[(n + 9) and $3F]) mod rndM; {== n - 55 mod 64}
+
+Result:= cirbuf[n]
+end;
+
+procedure SetRandomSeed(Seed: shortstring);
+var i: Longword;
+begin
+for i:= 0 to pred(Length(Seed)) do
+ cirbuf[i]:= byte(Seed[i + 1]) * 35791253;
+
+for i:= Length(Seed) to 63 do
+ cirbuf[i]:= i * 23860799;
+
+for i:= 0 to 1024 do GetNext;
end;
function GetRandom: real;
-var dig: TSHA1Digest;
begin
-SHA1Update(sc1, @Fill[1], Length(Fill));
-sc2:= sc1;
-dig:= SHA1Final(sc2);
-Result:= frac( dig.LongWords[0]*0.0000731563977
- + pi * dig.Words[6]
- + 0.0109070019*dig.Words[9])
+Result:= frac( GetNext * 0.0007301 + GetNext * 0.003019)
end;
-function GetRandom(m: LongWord): LongWord;
-var dig: TSHA1Digest;
+function GetRandom(m: LongWord): LongWord;
begin
-SHA1Update(sc1, @Fill[1], Length(Fill));
-sc2:= sc1;
-dig:= SHA1Final(sc2);
-Result:= (dig.LongWords[0] + dig.LongWords[2] + dig.LongWords[3]) mod m
+Result:= GetNext mod m
end;
end.