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#include "pi/CritSect.h"
#include "pi/Atomic.h"
#include "pi/Thread.h"
#include <assert.h>
CritSect::CritSect( bool do_construct ){_CFE_;
if( do_construct ){
m_cnt = 0;
m_thid = 0;
}
}
void CritSect::Enter( ){_CFE_;
int cnt = AtomicIncrement( &m_cnt );
if( m_thid==(int)piGetThreadId() ){
if( cnt>1 )
return; // Repeated entry
assert( !m_thid );
}
while( cnt>1 ){
if( !AtomicDecrement(&m_cnt) )
// If final release for other thread happened when we had temp increase
m_thid = 0;
piYield();
cnt = AtomicIncrement(&m_cnt);
}
// Have it
m_thid = piGetThreadId();
}
void CritSect::Leave( ){_CFE_;
int cnt = AtomicDecrement( &m_cnt );
if( !cnt )
// Thread leaving it
m_thid = 0;
else
// Check not released too many times
assert( cnt>0 );
}
bool CritSect::TryEnter( ){_CFE_;
int cnt = AtomicIncrement( &m_cnt );
if( m_thid==(int)piGetThreadId() ){
if( cnt>1 )
return true; // Repeated entry
assert( !m_thid );
}
// Have it
if( cnt==1 ){
m_thid = piGetThreadId();
return true;
}
else{
// Failed
AtomicDecrement( &m_cnt );
return false;
}
}
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