| 1 | /* $Id: nt_fullpath_cached.c 2849 2016-08-30 14:28:46Z bird $ */
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| 2 | /** @file
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| 3 | * fixcase - fixes the case of paths, windows specific.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (c) 2004-2010 knut st. osmundsen <bird-kBuild-spamx@anduin.net>
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| 8 | *
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| 9 | * This file is part of kBuild.
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| 10 | *
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| 11 | * kBuild is free software; you can redistribute it and/or modify
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| 12 | * it under the terms of the GNU General Public License as published by
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| 13 | * the Free Software Foundation; either version 3 of the License, or
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| 14 | * (at your option) any later version.
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| 15 | *
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| 16 | * kBuild is distributed in the hope that it will be useful,
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| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 19 | * GNU General Public License for more details.
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| 20 | *
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| 21 | * You should have received a copy of the GNU General Public License
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| 22 | * along with kBuild. If not, see <http://www.gnu.org/licenses/>
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| 23 | *
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| 24 | */
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| 25 |
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| 26 | /*******************************************************************************
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| 27 | * Header Files *
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| 28 | *******************************************************************************/
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| 29 | #include <Windows.h>
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| 30 | #include <stdio.h>
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| 31 | #include <stdlib.h>
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| 32 | #include <string.h>
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| 33 | #include <ctype.h>
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| 34 | #include <direct.h>
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| 35 | #include <assert.h>
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| 36 |
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| 37 | #include "nt_fullpath.h"
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| 38 |
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| 39 |
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| 40 | /*********************************************************************************************************************************
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| 41 | * Structures and Typedefs *
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| 42 | *********************************************************************************************************************************/
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| 43 | typedef struct NTFULLPATHENTRY
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| 44 | {
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| 45 | /** Pointer to the next entry with the same hash table index. */
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| 46 | struct NTFULLPATHENTRY *pNext;
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| 47 | /** The input hash. */
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| 48 | unsigned uHash;
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| 49 | /** The input length. */
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| 50 | unsigned cchInput;
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| 51 | /** Length of the result. */
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| 52 | unsigned cchResult;
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| 53 | /** The result string (stored immediately after this structure). */
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| 54 | const char *pszResult;
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| 55 | /** The input string (variable length). */
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| 56 | char szInput[1];
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| 57 | } NTFULLPATHENTRY;
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| 58 | typedef NTFULLPATHENTRY *PNTFULLPATHENTRY;
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| 59 |
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| 60 |
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| 61 | /*********************************************************************************************************************************
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| 62 | * Global Variables *
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| 63 | *********************************************************************************************************************************/
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| 64 | /** Number of result in the nt_fullpath cache. */
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| 65 | size_t g_cNtFullPathHashEntries = 0;
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| 66 | /** Number of bytes used for nt_fullpath cache result entries. */
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| 67 | size_t g_cbNtFullPathHashEntries = 0;
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| 68 | /** Number of hash table collsioins in the nt_fullpath cache. */
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| 69 | size_t g_cNtFullPathHashCollisions = 0;
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| 70 | /** Hash table. */
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| 71 | PNTFULLPATHENTRY g_apNtFullPathHashTab[16381];
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| 72 |
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| 73 |
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| 74 | /**
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| 75 | * A nt_fullpath frontend which caches the result of previous calls.
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| 76 | */
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| 77 | void
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| 78 | nt_fullpath_cached(const char *pszPath, char *pszFull, size_t cchFull)
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| 79 | {
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| 80 | PNTFULLPATHENTRY pEntry;
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| 81 | unsigned cchInput;
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| 82 | unsigned idx;
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| 83 | unsigned cchResult;
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| 84 |
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| 85 | /* We use the sdbm hash algorithm here (see kDep.c for full details). */
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| 86 | unsigned const char *puch = (unsigned const char *)pszPath;
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| 87 | unsigned uHash = 0;
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| 88 | unsigned uChar;
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| 89 | while ((uChar = *puch++) != 0)
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| 90 | uHash = uChar + (uHash << 6) + (uHash << 16) - uHash;
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| 91 |
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| 92 | cchInput = (unsigned)((uintptr_t)&puch[-1] - (uintptr_t)pszPath);
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| 93 |
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| 94 | /* Do the cache lookup. */
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| 95 | idx = uHash % (sizeof(g_apNtFullPathHashTab) / sizeof(g_apNtFullPathHashTab[0]));
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| 96 | for (pEntry = g_apNtFullPathHashTab[idx]; pEntry != NULL; pEntry = pEntry->pNext)
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| 97 | if ( pEntry->uHash == uHash
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| 98 | && pEntry->cchInput == cchInput
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| 99 | && memcmp(pEntry->szInput, pszPath, cchInput) == 0)
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| 100 | {
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| 101 | if (cchFull > pEntry->cchResult)
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| 102 | memcpy(pszFull, pEntry->pszResult, pEntry->cchResult + 1);
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| 103 | else
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| 104 | {
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| 105 | assert(0);
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| 106 | memcpy(pszFull, pEntry->pszResult, cchFull);
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| 107 | pszFull[cchFull - 1] = '\0';
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| 108 | }
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| 109 | return;
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| 110 | }
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| 111 |
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| 112 | /* Make the call... */
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| 113 | nt_fullpath(pszPath, pszFull, cchFull);
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| 114 |
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| 115 | /* ... and cache the result. */
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| 116 | cchResult = (unsigned)strlen(pszFull);
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| 117 | pEntry = malloc(sizeof(*pEntry) + cchInput + cchResult + 1);
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| 118 | if (pEntry)
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| 119 | {
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| 120 | g_cbNtFullPathHashEntries += sizeof(*pEntry) + cchInput + cchResult + 1;
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| 121 | pEntry->cchInput = cchInput;
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| 122 | pEntry->cchResult = cchResult;
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| 123 | pEntry->pszResult = &pEntry->szInput[cchInput + 1];
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| 124 | pEntry->uHash = uHash;
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| 125 | memcpy(pEntry->szInput, pszPath, cchInput + 1);
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| 126 | memcpy((char *)pEntry->pszResult, pszFull, cchResult + 1);
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| 127 |
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| 128 | pEntry->pNext = g_apNtFullPathHashTab[idx];
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| 129 | if (pEntry->pNext)
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| 130 | g_cNtFullPathHashCollisions++;
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| 131 | g_apNtFullPathHashTab[idx] = pEntry;
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| 132 |
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| 133 | g_cNtFullPathHashEntries++;
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| 134 | }
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| 135 | }
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| 136 |
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