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−(*
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− * Hedgewars, a worms-like game
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− * Copyright (c) 2004, 2005 Andrey Korotaev <unC0Rr@gmail.com>
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− *
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− * Distributed under the terms of the BSD-modified licence:
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− *
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− * Permission is hereby granted, free of charge, to any person obtaining a copy
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− * of this software and associated documentation files (the "Software"), to deal
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− * with the Software without restriction, including without limitation the
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− * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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− * sell copies of the Software, and to permit persons to whom the Software is
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− * furnished to do so, subject to the following conditions:
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− *
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− * 1. Redistributions of source code must retain the above copyright notice,
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− *    this list of conditions and the following disclaimer.
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− * 2. Redistributions in binary form must reproduce the above copyright notice,
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− *    this list of conditions and the following disclaimer in the documentation
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− *    and/or other materials provided with the distribution.
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− * 3. The name of the author may not be used to endorse or promote products
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− *    derived from this software without specific prior written permission.
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− *
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− * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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− * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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− * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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− * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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− * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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− * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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− * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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− * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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− * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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− * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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− *)
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−
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−unit uRandom;
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−interface
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−uses uSHA;
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−
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−procedure SetRandomParams(Seed: shortstring; FillBuf: shortstring);
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−function  GetRandom: real; overload;
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−function  GetRandom(m: LongWord): LongWord; overload;
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−
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−implementation
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−var  sc1, sc2: TSHA1Context;
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−     Fill: shortstring;
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−
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−procedure SetRandomParams(Seed: shortstring; FillBuf: shortstring);
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−begin
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−SHA1Init(sc1);
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−SHA1Update(sc1, @Seed, Length(Seed)+1);
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−Fill:= FillBuf
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−end;
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−
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−function GetRandom: real;
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−var dig: TSHA1Digest;
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−begin
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−SHA1Update(sc1, @Fill[1], Length(Fill));
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−sc2:= sc1;
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−dig:= SHA1Final(sc1);
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−Result:= frac( dig.LongWords[0]*0.0000731563977
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−               + pi * dig.Words[6]
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−               + 0.0109070019*dig.Words[9]);
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−sc1:= sc2
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−end;
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−
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−function  GetRandom(m: LongWord): LongWord;
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−var dig: TSHA1Digest;
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−begin
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−SHA1Update(sc1, @Fill[1], Length(Fill));
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−sc2:= sc1;
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−dig:= SHA1Final(sc1);
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−Result:= (((dig.LongWords[0] mod m) + (dig.LongWords[2] mod m)) mod m + (dig.LongWords[3] mod m)) mod m;
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−sc1:= sc2
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−end;
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−
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−end.