448 lines
11 KiB
C
448 lines
11 KiB
C
/*++
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Copyright (c) 1989-2000 Microsoft Corporation
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Module Name:
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hash.c
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Abstract:
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BUGBUG: comment.
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Author:
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vadimb created sometime in 2000
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Revision History:
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--*/
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#include "sdbp.h"
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#define DEFAULT_STR_HASH_SIZE 8147
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#if defined(KERNEL_MODE) && defined(ALLOC_DATA_PRAGMA)
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#pragma data_seg()
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#endif // KERNEL_MODE && ALLOC_DATA_PRAGMA
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//
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// Table used to calculate CRC32. This is used to generate
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// the hash index for strings.
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//
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static DWORD rgdwCrc[] =
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{
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0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL,
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0x076dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L,
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0x0edb8832L, 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L,
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0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 0x90bf1d91L,
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0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
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0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L,
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0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL,
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0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L,
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0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 0xa2677172L,
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0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
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0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L,
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0x32d86ce3L, 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
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0x26d930acL, 0x51de003aL, 0xc8d75180L, 0xbfd06116L,
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0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 0xb8bda50fL,
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0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
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0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL,
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0x76dc4190L, 0x01db7106L, 0x98d220bcL, 0xefd5102aL,
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0x71b18589L, 0x06b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L,
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0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, 0xe10e9818L,
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0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
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0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL,
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0x6c0695edL, 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L,
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0x65b0d9c6L, 0x12b7e950L, 0x8bbeb8eaL, 0xfcb9887cL,
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0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, 0xfbd44c65L,
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0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
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0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL,
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0x4369e96aL, 0x346ed9fcL, 0xad678846L, 0xda60b8d0L,
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0x44042d73L, 0x33031de5L, 0xaa0a4c5fL, 0xdd0d7cc9L,
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0x5005713cL, 0x270241aaL, 0xbe0b1010L, 0xc90c2086L,
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0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
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0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L,
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0x59b33d17L, 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL,
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0xedb88320L, 0x9abfb3b6L, 0x03b6e20cL, 0x74b1d29aL,
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0xead54739L, 0x9dd277afL, 0x04db2615L, 0x73dc1683L,
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0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
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0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L,
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0xf00f9344L, 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL,
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0xf762575dL, 0x806567cbL, 0x196c3671L, 0x6e6b06e7L,
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0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, 0x67dd4accL,
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0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
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0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L,
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0xd1bb67f1L, 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL,
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0xd80d2bdaL, 0xaf0a1b4cL, 0x36034af6L, 0x41047a60L,
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0xdf60efc3L, 0xa867df55L, 0x316e8eefL, 0x4669be79L,
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0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
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0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL,
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0xc5ba3bbeL, 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L,
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0xc2d7ffa7L, 0xb5d0cf31L, 0x2cd99e8bL, 0x5bdeae1dL,
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0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, 0x026d930aL,
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0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
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0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L,
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0x92d28e9bL, 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L,
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0x86d3d2d4L, 0xf1d4e242L, 0x68ddb3f8L, 0x1fda836eL,
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0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, 0x18b74777L,
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0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
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0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L,
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0xa00ae278L, 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L,
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0xa7672661L, 0xd06016f7L, 0x4969474dL, 0x3e6e77dbL,
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0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, 0x37d83bf0L,
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0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
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0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L,
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0xbad03605L, 0xcdd70693L, 0x54de5729L, 0x23d967bfL,
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0xb3667a2eL, 0xc4614ab8L, 0x5d681b02L, 0x2a6f2b94L,
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0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 0x2d02ef8dL
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};
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#if defined(KERNEL_MODE) && defined(ALLOC_PRAGMA)
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#pragma alloc_text(PAGE, HashCreate)
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#pragma alloc_text(PAGE, HashFree)
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#pragma alloc_text(PAGE, HashStringRef)
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#pragma alloc_text(PAGE, HashString)
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#pragma alloc_text(PAGE, HashFindString)
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#pragma alloc_text(PAGE, HashFindStringByRef)
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#pragma alloc_text(PAGE, HashAddString)
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#pragma alloc_text(PAGE, HashAddStringByRef)
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#endif // KERNEL_MODE && ALLOC_PRAGMA
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PVOID
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HashCreate(
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void
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)
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/*++
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Return: The hash.
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Desc: Creates and initializes the hash.
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--*/
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{
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PSTRHASH pHash;
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pHash = (PSTRHASH)SdbAlloc(sizeof(STRHASH));
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if (pHash == NULL) {
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DBGPRINT((sdlError,
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"HashCreate",
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"Failed to allocate %d bytes.\n",
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sizeof(STRHASH)));
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return NULL;
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}
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pHash->dwHashSize = DEFAULT_STR_HASH_SIZE;
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pHash->pTable = (PSTRHASHELEMENT*)SdbAlloc(sizeof(PSTRHASHELEMENT) * DEFAULT_STR_HASH_SIZE);
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if (pHash->pTable == NULL) {
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DBGPRINT((sdlError,
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"HashCreate",
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"Failed to allocate %d bytes for the table.\n",
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sizeof(PSTRHASHELEMENT) * DEFAULT_STR_HASH_SIZE));
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SdbFree(pHash);
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return NULL;
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}
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return pHash;
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}
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void
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HashFree(
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IN PVOID pStringHash // the hash to be freed.
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)
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/*++
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Return: void
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Desc: BUGBUG: comments ?
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--*/
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{
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PSTRHASHELEMENT phe, pheNext;
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PSTRHASH pHash = (PSTRHASH)pStringHash;
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int i;
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if (pHash == NULL) {
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DBGPRINT((sdlError, "HashFree", "Invalid argument.\n"));
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return;
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}
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if (pHash->pTable != NULL) {
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for (i = 0; i < (int)pHash->dwHashSize; i++) {
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for (phe = pHash->pTable[i]; phe != NULL; ) {
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pheNext = phe->pNext;
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SdbFree(phe);
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phe = pheNext;
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}
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}
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SdbFree(pHash->pTable);
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}
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SdbFree(pHash);
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}
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DWORD
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HashStringRef(
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IN PSTRHASH pHash, // pointer to the string hash structure.
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IN STRINGREF srString // string-reference (a dword) that is used to
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// identify the string in an sdb file.
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)
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/*++
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Return: Hash index for the string
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Desc: BUGBUG: comments ?
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--*/
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{
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//
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// really simple for now
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//
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return (srString % pHash->dwHashSize);
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}
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DWORD
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HashString(
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IN PSTRHASH pHash, // pointer to the string hash structure.
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IN LPCTSTR szString // the string to be hashed
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)
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/*++
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Return: The string reference in the hash.
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Desc: BUGBUG: comments ?
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--*/
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{
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DWORD dwHash = 0;
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while (*szString) {
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dwHash += (dwHash << 5) + dwHash + *szString++;
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}
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dwHash %= pHash->dwHashSize;
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return dwHash;
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}
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STRINGREF
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HashFindString(
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IN PSTRHASH pHash, // pointer to the string hash structure.
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IN LPCTSTR szString // string to search for.
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)
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/*++
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Return: The string ref if the string is found in the hash, 0 otherwise.
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Desc: Searches for the specified string in the hash table.
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--*/
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{
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DWORD dwHash;
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PSTRHASHELEMENT phe;
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int iCmp;
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STRINGREF srReturn = STRINGREF_NULL;
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dwHash = HashString(pHash, szString);
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phe = pHash->pTable[dwHash];
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for (; phe != NULL; phe = phe->pNext) {
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iCmp = _tcsicmp(szString, phe->szStr);
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//
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// The list of items related to the entry dwHash in the table
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// is sorted in ascending order by the "add" routine
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// therefore we compare until we find an item that is greater or equal
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// to the search string.
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//
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if (iCmp <= 0) {
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//
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// Found or failure, stop the search.
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//
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srReturn = (iCmp == 0 ? phe->srStr : STRINGREF_NULL);
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break;
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}
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}
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return srReturn;
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}
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LPTSTR
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HashFindStringByRef(
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IN PSTRHASH pHash, // pointer to the string hash structure.
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IN STRINGREF srString // stringref of the string to search for.
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)
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/*++
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Return: The pointer to the found string or NULL.
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Desc: Searches for the specified string in the hash table.
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--*/
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{
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DWORD dwHash;
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PSTRHASHELEMENT phe;
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LPTSTR pStr = NULL;
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dwHash = HashStringRef(pHash, srString);
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phe = pHash->pTable[dwHash];
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for (; phe != NULL; phe = phe->pNext) {
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if (phe->srStr >= srString) {
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pStr = ((phe->srStr == srString) ? phe->szStr : NULL);
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break;
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}
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}
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return pStr;
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}
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BOOL
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HashAddString(
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IN PSTRHASH pHash, // pointer to the string hash structure.
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IN LPCTSTR szString, // the string to be added
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IN STRINGREF srString // the string ref for the string to be added
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)
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/*++
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Return: TRUE on success, FALSE otherwise.
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Desc: BUGBUG: comments ?
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--*/
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{
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DWORD dwHash;
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PSTRHASHELEMENT phe;
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PSTRHASHELEMENT pheLast;
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PSTRHASHELEMENT pheNew;
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DWORD dwStrSize;
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BOOL bSuccess = FALSE;
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dwHash = HashString(pHash, szString);
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phe = pHash->pTable[dwHash];
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dwStrSize = (_tcslen(szString) + 1) * sizeof(TCHAR);
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//
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// Now check where to insert the string.
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//
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for (pheLast = NULL;
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phe != NULL && _tcsicmp(szString, phe->szStr) > 0;
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pheLast = phe, phe = phe->pNext) {
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;
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}
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//
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// Insert it.
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//
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pheNew = (PSTRHASHELEMENT)SdbAlloc(sizeof(STRHASHELEMENT) + dwStrSize);
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if (pheNew == NULL) {
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DBGPRINT((sdlError,
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"HashAddString",
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"Failed to allocate %d bytes.\n",
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sizeof(STRHASHELEMENT) + dwStrSize));
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return FALSE;
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}
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pheNew->szStr = (LPTSTR)(pheNew + 1);
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pheNew->srStr = srString;
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RtlMoveMemory(pheNew->szStr, szString, dwStrSize);
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pheNew->pNext = phe;
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if (pheLast == NULL) {
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pHash->pTable[dwHash] = pheNew;
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} else {
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pheLast->pNext = pheNew;
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}
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return TRUE;
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}
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LPTSTR
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HashAddStringByRef(
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IN PSTRHASH pHash,
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IN LPCTSTR szString,
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IN STRINGREF srString
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)
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/*++
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Return: The pointer to the string added in the hash table.
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Desc: BUGBUG: comments ?
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--*/
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{
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DWORD dwHash;
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PSTRHASHELEMENT phe;
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PSTRHASHELEMENT pheLast;
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PSTRHASHELEMENT pheNew;
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DWORD dwStrSize;
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LPTSTR lpszCachedString = NULL;
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dwHash = HashStringRef(pHash, srString);
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phe = pHash->pTable[dwHash];
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dwStrSize = (_tcslen(szString) + 1) * sizeof(TCHAR);
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//
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// Check where to insert the string.
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//
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for (pheLast = NULL;
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phe != NULL && srString > phe->srStr;
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pheLast = phe, phe = phe->pNext);
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//
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// Insert it.
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//
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pheNew = (PSTRHASHELEMENT)SdbAlloc(sizeof(STRHASHELEMENT) + dwStrSize);
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if (pheNew == NULL) {
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DBGPRINT((sdlError,
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"HashAddStringByRef",
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"Failed to allocate %d bytes.\n",
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sizeof(STRHASHELEMENT) + dwStrSize));
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return NULL;
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}
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pheNew->szStr = (LPTSTR)(pheNew + 1);
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pheNew->srStr = srString;
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RtlMoveMemory(pheNew->szStr, szString, dwStrSize);
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pheNew->pNext = phe;
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if (pheLast == NULL) {
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pHash->pTable[dwHash] = pheNew;
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} else {
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pheLast->pNext = pheNew;
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}
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lpszCachedString = pheNew->szStr;
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return lpszCachedString;
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}
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