source-engine-2018-hl2_src/common/cstringhash.h
FluorescentCIAAfricanAmerican 3bf9df6b27 1
2020-04-22 12:56:21 -04:00

118 lines
2.4 KiB
C++

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================//
#ifndef CSTRINGHASH_H
#define CSTRINGHASH_H
#pragma once
#include "string.h"
#define STRING_HASH_TABLE_SIZE 701
template <class T> class CStringHash
{
public:
CStringHash()
{
memset( m_HashTable, 0, sizeof( StringHashNode_t * ) * STRING_HASH_TABLE_SIZE );
}
~CStringHash()
{
int i;
for( i = 0; i < STRING_HASH_TABLE_SIZE; i++ )
{
StringHashNode_t *curEntry;
curEntry = m_HashTable[i];
if( curEntry )
{
StringHashNode_t *next;
next = curEntry->next;
delete curEntry;
curEntry = next;
}
}
}
// return false if it already exists
// there can only be one entry for each string.
bool Insert( const char *string, T val )
{
unsigned int hashID = HashString( string );
StringHashNode_t *newEntry;
if( !m_HashTable[hashID] )
{
// first on at this hashID
// fixme: need to make the allocation function configurable.
newEntry = m_HashTable[hashID] = new StringHashNode_t;
newEntry->next = NULL;
}
else
{
StringHashNode_t *curEntry;
curEntry = m_HashTable[hashID];
while( curEntry )
{
if( stricmp( curEntry->string, string ) == 0 )
{
// replace the data at the current entry with the enw data.
curEntry->data = val;
return false;
}
curEntry = curEntry->next;
}
newEntry = new StringHashNode_t;
newEntry->next = m_HashTable[hashID];
m_HashTable[hashID] = newEntry;
}
int len = strlen( string ) + 1;
newEntry->string = new char[len];
Q_strncpy( newEntry->string, string, len );
newEntry->data = val;
return true;
}
T Find( const char *string )
{
int hashID = HashString( string );
StringHashNode_t *curEntry;
curEntry = m_HashTable[hashID];
while( curEntry )
{
if( stricmp( curEntry->string, string ) == 0 )
{
return curEntry->data;
}
curEntry = curEntry->next;
}
return NULL;
}
private:
unsigned int HashString( const char *string )
{
const char *s = string;
unsigned int result = 0;
while( *s )
{
result += tolower( ( int )*s ) * 6029;
result *= 5749;
s++;
}
return result % STRING_HASH_TABLE_SIZE;
}
typedef struct StringHashNode_s
{
char *string;
T data;
struct StringHashNode_s *next;
} StringHashNode_t;
StringHashNode_t *m_HashTable[STRING_HASH_TABLE_SIZE];
};
#endif // CSTRINGHASH_H