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Clean up the FNV-1 comments.

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[SVN r47143]
This commit is contained in:
Daniel James
2008-07-06 21:06:52 +00:00
parent f723f857e4
commit 2960390f79
1 changed files with 16 additions and 21 deletions
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37
examples/hash_functions/fnv-1.hpp
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@ -3,6 +3,8 @@
// Distributed under the Boost Software License, Version 1.0. (See accompanying // Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
// This code is also released into the public domain.
// Algorithm from: http://www.isthe.com/chongo/tech/comp/fnv/ // Algorithm from: http://www.isthe.com/chongo/tech/comp/fnv/
#include <string> #include <string>
@ -43,29 +45,22 @@ namespace hash
} }
}; };
// TODO: Select Basis & Prime base on the size of std::size_t. // For 32 bit machines:
// const std::size_t fnv_prime = 16777619u;
// 32 bit FNV_prime = 16777619
// 64 bit FNV_prime = 1099511628211
// 128 bit FNV_prime = 309485009821345068724781401
// 256 bit FNV_prime = 374144419156711147060143317175368453031918731002211
//
// 32 bit offset_basis = 2166136261
// 64 bit offset_basis = 14695981039346656037
// 128 bit offset_basis = 275519064689413815358837431229664493455
// 256 bit offset_basis = 100029257958052580907070968620625704837092796014241193945225284501741471925557
const std::size_t fnv_prime = 16777619;
// 64 bit FNV_prime = 1099511628211
// 128 bit FNV_prime = 309485009821345068724781401
// 256 bit FNV_prime = 374144419156711147060143317175368453031918731002211
const std::size_t fnv_offset_basis = 2166136261u; const std::size_t fnv_offset_basis = 2166136261u;
// 64 bit offset_basis = 14695981039346656037
// 128 bit offset_basis = 275519064689413815358837431229664493455 // For 64 bit machines:
// 256 bit offset_basis = 100029257958052580907070968620625704837092796014241193945225284501741471925557 // const std::size_t fnv_prime = 1099511628211u;
// const std::size_t fnv_offset_basis = 14695981039346656037u;
// For 128 bit machines:
// const std::size_t fnv_prime = 309485009821345068724781401u;
// const std::size_t fnv_offset_basis = 275519064689413815358837431229664493455u;
// For 256 bit machines:
// const std::size_t fnv_prime = 374144419156711147060143317175368453031918731002211u;
// const std::size_t fnv_offset_basis = 100029257958052580907070968620625704837092796014241193945225284501741471925557u;
typedef basic_fnv_1<fnv_prime, fnv_offset_basis> fnv_1; typedef basic_fnv_1<fnv_prime, fnv_offset_basis> fnv_1;
typedef basic_fnv_1a<fnv_prime, fnv_offset_basis> fnv_1a; typedef basic_fnv_1a<fnv_prime, fnv_offset_basis> fnv_1a;
} }