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libavutil
lfg.h
Go to the documentation of this file.
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/*
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* Lagged Fibonacci PRNG
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* Copyright (c) 2008 Michael Niedermayer
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVUTIL_LFG_H
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#define AVUTIL_LFG_H
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typedef
struct
{
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unsigned
int
state
[64];
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int
index
;
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}
AVLFG
;
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void
av_lfg_init
(
AVLFG
*c,
unsigned
int
seed
);
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static
inline
unsigned
int
av_lfg_get
(
AVLFG
*c){
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c->
state
[c->
index
& 63] = c->
state
[(c->
index
-24) & 63] + c->
state
[(c->
index
-55) & 63];
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return
c->
state
[c->
index
++ & 63];
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}
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static
inline
unsigned
int
av_mlfg_get
(
AVLFG
*c){
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unsigned
int
a= c->
state
[(c->
index
-55) & 63];
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unsigned
int
b
= c->
state
[(c->
index
-24) & 63];
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return
c->
state
[c->
index
++ & 63] = 2*a*b+a+
b
;
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}
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void
av_bmg_get
(
AVLFG
*lfg,
double
out[2]);
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#endif
/* AVUTIL_LFG_H */