bsearch.hpp

mini http server,可以集成嵌入到程序中,实现简单的web功能

/*____________________________________________________________________________*\
 *

 Copyright (c) 1997-2003 John Roy, Holger Zimmermann. All rights reserved.

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    derived from this software without specific prior written permission.

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 *____________________________________________________________________________*|
 *
 * $Source: /cvsroot/pi3web/Pi3Web_200/Source/Base/BSearch.hpp,v $
 * $Date: 2003/05/13 18:41:55 $
 *
 Description:
\*____________________________________________________________________________*/

#ifndef BSEARCH_HPP_
#define BSEARCH_HPP_

#include "BSearch.h"

/*____________________________________________________________________________*\
 *
 Function:
 Synopsis:
 Description:
\*____________________________________________________________________________*/
template<class T>
BSearch<T>::BSearch()
:	iCompiled( 0 ),
	iNumberOfEntries( 0 ),
	ppLinear( 0 )
{
}

/*____________________________________________________________________________*\
 *
 Function:
 Synopsis:
 Description:
\*____________________________________________________________________________*/
template<class T>
BSearch<T>::~BSearch()
{
	for( DblListIterator i( lRawEntries ); !i.BadIndex(); i++ )
		{
		PI_DELETE( (Entry *)i.Current() );
		};
	for( int j=0; j<iNumberOfEntries; j++ )
		{
		PI_DELETE( ppLinear[j] );
		};
	delete [] ppLinear;
}

/*____________________________________________________________________________*\
 *
 Function:
 Synopsis:
 Description:
	Add a before element into the table. This must happen before the list
	is generated. Returns non-zero on success, 0 on error. An attempt to
	add an entry which would cause a duplicate key is considered an error 
	condition.
\*____________________________________________________________________________*/
template<class T>
int BSearch<T>::Add( const char *pKey, T tElement )
{
	/* --- sanity, etc. --- */
	assert( pKey );
	if ( !pKey || iCompiled || ppLinear )
		{ return 0; };

	/* --- check if entry already exists --- */
	for( DblListIterator i( lRawEntries ); !i.BadIndex(); i++ )
		{
		Entry *pRE = (Entry *)i.Current();
		assert( pRE );
		if ( pRE->sKey==pKey )	/* --- invokes PIString::operator==() --- */
			{ /* --- key already exists --- */ return 0; };
		};

	/* --- key does not already exists, insert new raw entry --- */
	lRawEntries.Append( (DblList::type) PI_NEW( Entry( pKey, tElement ) ) );

	return 1;
}

/*____________________________________________________________________________*\
 *
 Function:
 Synopsis:
 Description:
	Little comparision function for callback by qsort().
\*____________________________________________________________________________*/
template<class T>
int BSearch<T>::fnSortEntryComparision( const void *pV1, const void *pV2 )
{
	const PIString &sKey1 = (*((Entry **)pV1))->sKey;
	const PIString &sKey2 = (*((Entry **)pV2))->sKey;
	int iCmp = sKey1.Len() - sKey2.Len();
	if ( !iCmp )
		{ return strcmp( sKey1, sKey2 ); }
	else
		{ return iCmp; };
}
 
/*____________________________________________________________________________*\
 *
 Function:
 Synopsis:
 Description:
	Little comparision function for callback by bsearch().
\*____________________________________________________________________________*/
template<class T>
int BSearch<T>::fnSearchEntryComparision( const void *pV1, const void *pV2 )
{
	const PIString &sKey1 = *((PIString *)pV1);
	const PIString &sKey2 = (*((Entry **)pV2))->sKey;
	int iCmp = sKey1.Len() - sKey2.Len();
	if ( !iCmp )
		{ return strcmp( sKey1, sKey2 ); }
	else
		{ return iCmp; };
}
 
/*____________________________________________________________________________*\
 *
 Function:
 Synopsis:
 Description:
	Compile raw entries into a sorted linear array for bsearch().
	This can only be done once.
\*____________________________________________________________________________*/
template<class T>
int BSearch<T>::Compile()
{
	if ( iCompiled )
		{ /* --- already compiled --- */; return 0; };

	/* --- 
	There are 2 stages to generating linear array
	--- */

	/* ---
	Stage 1: convert the raw entries linked list into an linear array of
	objects of type Entry
	--- */
	iNumberOfEntries = lRawEntries.Size();
	ppLinear = PI_NEW( Entry *[iNumberOfEntries] );
	int j=0;
	for( DblListIterator i( lRawEntries ); !i.BadIndex(); i++ )
		{
		ppLinear[j++] = (Entry *)i.Current();
		};
	lRawEntries.Clear();
	assert( j==iNumberOfEntries );

	/* ---
	Stage 2: Sort the linear array by the keys
	--- */
	qsort( ppLinear, iNumberOfEntries, sizeof( Entry * ),
		fnSortEntryComparision );

	iCompiled = 1;
	return 1;
}

/*____________________________________________________________________________*\
 *
 Function:
 Synopsis:
 Description:
	Binary tree lookup of an entry given a key.

	Try to do everything possible so this becomes an inline function.
\*____________________________________________________________________________*/
template<class T>
inline T BSearch<T>::Lookup( const PIString &sKey ) const
{
	/* --- sanity --- */
	assert( iCompiled && ppLinear && iNumberOfEntries );
	
	/* --- CAUTION: no run time checking that Compile() has been invoked for
	production builds. This will most certainly crash if Compile() has not
	been called 
	--- */
	Entry **ppEntry = (Entry **)bsearch( &sKey, ppLinear, iNumberOfEntries, 
		sizeof( Entry * ), fnSearchEntryComparision );

	return ppEntry ? ( (*ppEntry)->tElement ) : 0;
}

#endif /* BSEARCH_HPP_ */