55 lines
1.9 KiB
C
55 lines
1.9 KiB
C
/* Copyright (C) 2009 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* =========================================================================
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* File : fnv_hash.h
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* Project : 0 A.D.
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* Description : Fowler/Noll/Vo string hash
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* =========================================================================
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*/
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#ifndef INCLUDED_FNV_HASH
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#define INCLUDED_FNV_HASH
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/**
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* rationale: this algorithm was chosen because it delivers 'good' results
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* for string data and is relatively simple. other good alternatives exist;
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* see Ozan Yigit's hash roundup.
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**/
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/**
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* calculate FNV1-A hash.
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*
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* @param buf input buffer.
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* @param len if 0 (default), treat buf as a C-string; otherwise,
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* indicates how many bytes of buffer to hash.
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* @return hash result. note: results are distinct for buffers containing
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* differing amounts of zero bytes because the hash value is seeded.
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**/
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extern u32 fnv_hash(const void* buf, size_t len = 0);
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/// 64-bit version of fnv_hash.
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extern u64 fnv_hash64(const void* buf, size_t len = 0);
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/**
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* special version of fnv_hash for strings: first converts to lowercase
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* (useful for comparing mixed-case filenames)
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**/
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extern u32 fnv_lc_hash(const char* str, size_t len = 0);
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#endif // #ifndef INCLUDED_FNV_HASH
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