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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libc/] [sys/] [linux/] [include/] [dl-hash.h] - Rev 207
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/* Compute hash value for given string according to ELF standard. Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #ifndef _DL_HASH_H #define _DL_HASH_H 1 /* This is the hashing function specified by the ELF ABI. In the first five operations no overflow is possible so we optimized it a bit. */ static inline unsigned int _dl_elf_hash (const unsigned char *name) { unsigned long int hash = 0; if (*name != '\0') { hash = *name++; if (*name != '\0') { hash = (hash << 4) + *name++; if (*name != '\0') { hash = (hash << 4) + *name++; if (*name != '\0') { hash = (hash << 4) + *name++; if (*name != '\0') { hash = (hash << 4) + *name++; while (*name != '\0') { unsigned long int hi; hash = (hash << 4) + *name++; hi = hash & 0xf0000000; /* The algorithm specified in the ELF ABI is as follows: if (hi != 0) hash ^= hi >> 24; hash &= ~hi; But the following is equivalent and a lot faster, especially on modern processors. */ hash ^= hi; hash ^= hi >> 24; } } } } } } return hash; } #endif /* dl-hash.h */