Source code of Windows XP (NT5)
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/*++
Copyright (c) 2000 Microsoft Corporation
Module Name:
hashtable.cpp
Abstract:
This file contains the class definitions for hashtables
Author:
Vishnu Patankar (VishnuP) 7-April-2000
Environment:
User Mode - Win32
Revision History:
--*/
///////////////////////////////////////////////////////////////////////////////
// //
// Includes //
// //
///////////////////////////////////////////////////////////////////////////////
#include "hashtable.h"
///////////////////////////////////////////////////////////////////////////////
// Constructor
//
// in: dwNumBuckets - the hashtable size
// out:
// return value:
//
// description: creates the hashtable
// if unable to get memory, bInitialized is set to FALSE
///////////////////////////////////////////////////////////////////////////////
ScepHashTable::ScepHashTable(DWORD dwNumBuckets){
if (aTable = (PSCE_PRECEDENCE_NAME_LIST*)ScepAlloc(LMEM_ZEROINIT,
dwNumBuckets * sizeof(PSCE_PRECEDENCE_NAME_LIST))){
NumBuckets = dwNumBuckets;
bInitialized = TRUE;
}
else
bInitialized = FALSE;
}
///////////////////////////////////////////////////////////////////////////////
// Destructor
//
// in:
// out:
// return value:
//
// description: frees memory associated with the hashtable
///////////////////////////////////////////////////////////////////////////////
ScepHashTable::~ScepHashTable(){
if (bInitialized) {
for (DWORD BucketNo = 0 ; BucketNo < NumBuckets; BucketNo++)
if (aTable[BucketNo])
ScepFreeNameStatusList(aTable[BucketNo]);
ScepFree(aTable);
bInitialized = FALSE;
}
}
///////////////////////////////////////////////////////////////////////////////
// Lookup() method
//
// in: pName - key to search for in the hashtable
// out:
// return value: pointer to hashtable node if found or NULL if none
//
// description: searches the bucket that pName hashed into
// if found, returns the node, else returns NULL
///////////////////////////////////////////////////////////////////////////////
PSCE_PRECEDENCE_NAME_LIST
ScepHashTable::Lookup(
PWSTR pName
)
{
PSCE_PRECEDENCE_NAME_LIST pNameList;
for (pNameList = aTable[ScepGenericHash(pName)]; pNameList != NULL; pNameList = pNameList->Next)
if (_wcsicmp(pName, pNameList->Name) == 0)
return pNameList;
return NULL;
}
///////////////////////////////////////////////////////////////////////////////
// LookupAdd() method
//
// in: pName - key to search for in the hashtable
// out: ppSettingPrecedence - pointer to pointer to the precedence of key
// return value: if out of resources error status, otherwise success
//
// description: if pName found, it returns a pointer to its precedence by reference
// else, it attempts to create a node and copy the name
// else it returns error out of resources
///////////////////////////////////////////////////////////////////////////////
DWORD
ScepHashTable::LookupAdd(
PWSTR pName,
DWORD **ppSettingPrecedence
)
{
DWORD rc = NO_ERROR;
if (bInitialized) {
if (pName && ppSettingPrecedence && *ppSettingPrecedence == NULL) {
PSCE_PRECEDENCE_NAME_LIST pNameList = Lookup(pName);
if (pNameList == NULL) {
if (NO_ERROR == (rc = ScepAddToNameStatusList(
&(aTable[ScepGenericHash(pName)]),
pName,
wcslen(pName),
0)))
*ppSettingPrecedence = &(aTable[ScepGenericHash(pName)]->Status);
}
else {
*ppSettingPrecedence = &(pNameList->Status);
}
} else {
rc = ERROR_INVALID_PARAMETER;
}
}
else {
rc = ERROR_NOT_ENOUGH_MEMORY;
}
return rc;
}
///////////////////////////////////////////////////////////////////////////////
// ScepGenericHash() method
//
// in: pwszName - key to hash
// out:
// return value: hashvalue
//
// description: calculates hash value for the name (to be made virtual)
//
///////////////////////////////////////////////////////////////////////////////
DWORD
ScepHashTable::ScepGenericHash(
PWSTR pwszName
)
{
DWORD hashval = 0;
for (; *pwszName != L'\0'; pwszName++)
hashval = towlower(*pwszName) + 47 * hashval;
return hashval % NumBuckets;
}
#ifdef _DEBUG
void
ScepHashTable::ScepDumpTable()
{
if (bInitialized) {
for (DWORD BucketNo = 0 ; BucketNo < NumBuckets; BucketNo++) {
PSCE_PRECEDENCE_NAME_LIST pNameList, pNode;
for (pNameList = aTable[BucketNo]; pNameList != NULL;) {
pNode = pNameList;
pNameList = pNameList->Next;
wprintf(L"\nBucket: %i, Name: %s, Precedence %i", BucketNo, pNode->Name, pNode->Status);
}
}
}
}
#endif