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make buffering optional, to avoid accumulative overhead

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This commit is contained in:
Glenn Maynard
2004-12-11 02:53:22 +00:00
parent a946c220bc
commit 614dfefd49
2 changed files with 115 additions and 22 deletions
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stepmania/src/RageFileBasic.cpp
+67 -20
View File
@@ -4,6 +4,8 @@
RageFileObj::RageFileObj()
{
m_pBuffer = NULL;
ResetBuf();
m_iBufAvail = 0;
@@ -11,6 +13,11 @@ RageFileObj::RageFileObj()
m_iFilePos = 0;
}
RageFileObj::~RageFileObj()
{
delete [] m_pBuffer;
}
int RageFileObj::Seek( int iOffset )
{
m_bEOF = false;
@@ -41,26 +48,29 @@ int RageFileObj::Read( void *pBuffer, size_t iBytes )
while( !m_bEOF && iBytes > 0 )
{
/* Copy data out of the buffer first. */
int FromBuffer = min( (int) iBytes, m_iBufAvail );
memcpy( pBuffer, m_pBuf, FromBuffer );
if( m_pBuffer != NULL && m_iBufAvail )
{
/* Copy data out of the buffer first. */
int iFromBuffer = min( (int) iBytes, m_iBufAvail );
memcpy( pBuffer, m_pBuf, iFromBuffer );
ret += FromBuffer;
m_iFilePos += FromBuffer;
iBytes -= FromBuffer;
m_iBufAvail -= FromBuffer;
m_pBuf += FromBuffer;
ret += iFromBuffer;
m_iFilePos += iFromBuffer;
iBytes -= iFromBuffer;
m_iBufAvail -= iFromBuffer;
m_pBuf += iFromBuffer;
pBuffer = (char *) pBuffer + FromBuffer;
pBuffer = (char *) pBuffer + iFromBuffer;
}
if( !iBytes )
break;
ASSERT( m_iBufAvail == 0 );
/* We need more; either fill the buffer and keep going, or just read directly
* into the destination buffer. */
if( iBytes >= sizeof(m_Buffer) )
/* If buffering is disabled, or the block is bigger than the buffer,
* read the remainder of the data directly into the desteination buffer. */
if( m_pBuffer == NULL || iBytes >= BSIZE )
{
/* We have a lot more to read, so don't waste time copying it into the
* buffer. */
@@ -75,9 +85,10 @@ int RageFileObj::Read( void *pBuffer, size_t iBytes )
return ret;
}
m_pBuf = m_Buffer;
/* If buffering is enabled, and we need more data, fill the buffer. */
m_pBuf = m_pBuffer;
int got = FillBuf();
if( got < 0 )
if( got == -1 )
return got;
if( got == 0 )
m_bEOF = true;
@@ -147,6 +158,12 @@ int RageFileObj::Flush()
}
void RageFileObj::EnableBuffering()
{
if( m_pBuffer == NULL )
m_pBuffer = new char[BSIZE];
}
/* Read up to the next \n, and return it in out. Strip the \n. If the \n is
* preceded by a \r (DOS newline), strip that, too. */
int RageFileObj::GetLine( CString &out )
@@ -156,6 +173,8 @@ int RageFileObj::GetLine( CString &out )
if( m_bEOF )
return 0;
EnableBuffering();
bool GotData = false;
while( 1 )
{
@@ -203,8 +222,8 @@ int RageFileObj::GetLine( CString &out )
if( ReAddCR )
{
ASSERT( m_iBufAvail == 0 );
m_pBuf = m_Buffer;
m_Buffer[m_iBufAvail] = '\r';
m_pBuf = m_pBuffer;
m_pBuffer[m_iBufAvail] = '\r';
++m_iBufAvail;
}
@@ -212,7 +231,7 @@ int RageFileObj::GetLine( CString &out )
break;
/* We need more data. */
m_pBuf = m_Buffer;
m_pBuf = m_pBuffer;
const int size = FillBuf();
@@ -251,11 +270,14 @@ int RageFileObj::PutLine( const CString &str )
* shouldn't cause the results of AtEOF to change.) */
int RageFileObj::FillBuf()
{
/* Don't call this unless buffering is enabled. */
ASSERT( m_pBuffer != NULL );
/* The buffer starts at m_Buffer; any data in it starts at m_pBuf; space between
* the two is old data that we've read. (Don't mangle that data; we can use it
* for seeking backwards.) */
const int iBufAvail = sizeof(m_Buffer) - (m_pBuf-m_Buffer) - m_iBufAvail;
ASSERT_M( iBufAvail >= 0, ssprintf("%p, %p, %i", m_pBuf, m_Buffer, (int) sizeof(m_Buffer) ) );
const int iBufAvail = BSIZE - (m_pBuf-m_pBuffer) - m_iBufAvail;
ASSERT_M( iBufAvail >= 0, ssprintf("%p, %p, %i", m_pBuf, m_pBuffer, (int) BSIZE ) );
const int size = this->ReadInternal( m_pBuf+m_iBufAvail, iBufAvail );
if( size > 0 )
@@ -267,6 +289,31 @@ int RageFileObj::FillBuf()
void RageFileObj::ResetBuf()
{
m_iBufAvail = 0;
m_pBuf = m_Buffer;
m_pBuf = m_pBuffer;
}
/*
* Copyright (c) 2003-2004 Glenn Maynard
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, and/or sell copies of the Software, and to permit persons to
* whom the Software is furnished to do so, provided that the above
* copyright notice(s) and this permission notice appear in all copies of
* the Software and that both the above copyright notice(s) and this
* permission notice appear in supporting documentation.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
* THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
* INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
* OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
* OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
stepmania/src/RageFileBasic.h
+48 -2
View File
@@ -1,3 +1,5 @@
/* RageFileBasic - simple file interface. */
#ifndef RAGE_FILE_BASIC_H
#define RAGE_FILE_BASIC_H
@@ -54,7 +56,7 @@ class RageFileObj: public RageFileBasic
{
public:
RageFileObj();
virtual ~RageFileObj() { }
virtual ~RageFileObj();
virtual CString GetError() const { return m_sError; }
virtual void ClearError() { SetError(""); }
@@ -88,6 +90,8 @@ protected:
virtual int WriteInternal( const void *pBuffer, size_t iBytes ) = 0;
virtual int FlushInternal() { return 0; }
void EnableBuffering();
void SetError( const CString &sError ) { m_sError = sError; }
CString m_sError;
@@ -98,11 +102,53 @@ private:
bool m_bEOF;
int m_iFilePos;
/*
* If buffering is enabled, m_pBuffer is the buffer, m_pBuf is the current read
* position in the buffer and m_iBufAvail is the number of bytes at m_pBuf. Note
* that buffering is only enabled if:
*
* - GetLine() is called (which requires buffering to efficiently search for newlines);
* - or EnableBuffering() is called
*
* Currently, once buffering is enabled, it stays enabled for the life of the
* object.
*
* If buffering is not enabled, this buffer will not be allocated, keeping the
* size overhead of each file down. Layered RageFileBasic implementations, which
* read from other RageFileBasics, should generally not use buffering, in order
* to avoid reads being passed through several buffers, which is only a waste of
* memory.
*/
enum { BSIZE = 1024 };
char m_Buffer[BSIZE];
char *m_pBuffer;
char *m_pBuf;
int m_iBufAvail;
};
#endif
/*
* Copyright (c) 2003-2004 Glenn Maynard, Chris Danford, Steve Checkoway
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, and/or sell copies of the Software, and to permit persons to
* whom the Software is furnished to do so, provided that the above
* copyright notice(s) and this permission notice appear in all copies of
* the Software and that both the above copyright notice(s) and this
* permission notice appear in supporting documentation.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
* THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
* INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
* OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
* OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/