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/* $Id: nt_fullpath_cached.c 2849 2016-08-30 14:28:46Z bird $ */
/** @file
* fixcase - fixes the case of paths, windows specific.
*/
/*
* Copyright (c) 2004-2010 knut st. osmundsen <bird-kBuild-spamx@anduin.net>
*
* This file is part of kBuild.
*
* kBuild is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* kBuild is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with kBuild. If not, see <http://www.gnu.org/licenses/>
*
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#include <Windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <direct.h>
#include <assert.h>
#include "nt_fullpath.h"
/*********************************************************************************************************************************
* Structures and Typedefs *
*********************************************************************************************************************************/
typedef struct NTFULLPATHENTRY
{
/** Pointer to the next entry with the same hash table index. */
struct NTFULLPATHENTRY *pNext;
/** The input hash. */
unsigned uHash;
/** The input length. */
unsigned cchInput;
/** Length of the result. */
unsigned cchResult;
/** The result string (stored immediately after this structure). */
const char *pszResult;
/** The input string (variable length). */
char szInput[1];
} NTFULLPATHENTRY;
typedef NTFULLPATHENTRY *PNTFULLPATHENTRY;
/*********************************************************************************************************************************
* Global Variables *
*********************************************************************************************************************************/
/** Number of result in the nt_fullpath cache. */
size_t g_cNtFullPathHashEntries = 0;
/** Number of bytes used for nt_fullpath cache result entries. */
size_t g_cbNtFullPathHashEntries = 0;
/** Number of hash table collsioins in the nt_fullpath cache. */
size_t g_cNtFullPathHashCollisions = 0;
/** Hash table. */
PNTFULLPATHENTRY g_apNtFullPathHashTab[16381];
/**
* A nt_fullpath frontend which caches the result of previous calls.
*/
void
nt_fullpath_cached(const char *pszPath, char *pszFull, size_t cchFull)
{
PNTFULLPATHENTRY pEntry;
unsigned cchInput;
unsigned idx;
unsigned cchResult;
/* We use the sdbm hash algorithm here (see kDep.c for full details). */
unsigned const char *puch = (unsigned const char *)pszPath;
unsigned uHash = 0;
unsigned uChar;
while ((uChar = *puch++) != 0)
uHash = uChar + (uHash << 6) + (uHash << 16) - uHash;
cchInput = (unsigned)((uintptr_t)&puch[-1] - (uintptr_t)pszPath);
/* Do the cache lookup. */
idx = uHash % (sizeof(g_apNtFullPathHashTab) / sizeof(g_apNtFullPathHashTab[0]));
for (pEntry = g_apNtFullPathHashTab[idx]; pEntry != NULL; pEntry = pEntry->pNext)
if ( pEntry->uHash == uHash
&& pEntry->cchInput == cchInput
&& memcmp(pEntry->szInput, pszPath, cchInput) == 0)
{
if (cchFull > pEntry->cchResult)
memcpy(pszFull, pEntry->pszResult, pEntry->cchResult + 1);
else
{
assert(0);
memcpy(pszFull, pEntry->pszResult, cchFull);
pszFull[cchFull - 1] = '\0';
}
return;
}
/* Make the call... */
nt_fullpath(pszPath, pszFull, cchFull);
/* ... and cache the result. */
cchResult = (unsigned)strlen(pszFull);
pEntry = malloc(sizeof(*pEntry) + cchInput + cchResult + 1);
if (pEntry)
{
g_cbNtFullPathHashEntries += sizeof(*pEntry) + cchInput + cchResult + 1;
pEntry->cchInput = cchInput;
pEntry->cchResult = cchResult;
pEntry->pszResult = &pEntry->szInput[cchInput + 1];
pEntry->uHash = uHash;
memcpy(pEntry->szInput, pszPath, cchInput + 1);
memcpy((char *)pEntry->pszResult, pszFull, cchResult + 1);
pEntry->pNext = g_apNtFullPathHashTab[idx];
if (pEntry->pNext)
g_cNtFullPathHashCollisions++;
g_apNtFullPathHashTab[idx] = pEntry;
g_cNtFullPathHashEntries++;
}
}
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