60 lines
1.1 KiB
C
60 lines
1.1 KiB
C
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#ifndef SKHASH_H
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#define SKHASH_H
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// skhash.h
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// 8/1/2011
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#include "sakurakit/skglobal.h"
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#include <QtGlobal>
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SK_BEGIN_NAMESPACE
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enum : quint64 { djb2_hash0 = 5381 };
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/// djb2: h = h*33 + c
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inline quint64 djb2(const quint8 *str, quint64 hash = djb2_hash0)
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{
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quint8 c;
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while ((c = *str++))
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hash = ((hash << 5) + hash) + c; // hash * 33 + c
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return hash;
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}
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/// s: signed char
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inline quint64 djb2_s(const char *str, quint64 hash = djb2_hash0)
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{
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char c;
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while ((c = *str++))
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hash = ((hash << 5) + hash) + c; // hash * 33 + c
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return hash;
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}
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/// n: length
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inline quint64 djb2_n(const quint8 *str, size_t len, quint64 hash = djb2_hash0)
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{
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while (len--)
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hash = ((hash << 5) + hash) + (*str++); // hash * 33 + c
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return hash;
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}
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/// sdbm: hash(i) = hash(i - 1) * 65599 + str[i];
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inline quint64 sdbm(const quint8 *str, quint64 hash = 0)
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{
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quint8 c;
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while ((c = *str++))
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hash = c + (hash << 6) + (hash << 16) - hash;
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return hash;
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}
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inline quint64 loselose(const quint8 *str, quint64 hash = 0)
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{
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quint8 c;
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while ((c = *str++))
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hash += c;
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return hash;
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}
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SK_END_NAMESPACE
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#endif // SKHASH_H
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