27 lines
979 B
C
27 lines
979 B
C
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#ifndef COSMOPOLITAN_LIBC_STR_KNUTHMULTIPLICATIVEHASH_H_
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#define COSMOPOLITAN_LIBC_STR_KNUTHMULTIPLICATIVEHASH_H_
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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COSMOPOLITAN_C_START_
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forceinline uint32_t KnuthMultiplicativeHash32(const void *buf, size_t size) {
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/* frozen due to presence in sqlite & promise in libc/getuid.c */
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const unsigned char *const p = (const unsigned char *)buf;
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uint32_t hash = 0, kPhiPrime = 0x9e3779b1;
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size_t i;
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for (i = 0; i < size; i++) hash = (p[i] + hash) * kPhiPrime;
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return hash;
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}
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forceinline uint64_t KnuthMultiplicativeHash(const void *buf, size_t size) {
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/* TODO(jart): verify w/ primary source */
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const unsigned char *const p = (const unsigned char *)buf;
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uint64_t hash = 0, kPhiPrime = 0x9e3779b9925d4c17;
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size_t i;
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for (i = 0; i < size; i++) hash = (p[i] + hash) * kPhiPrime;
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return hash;
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}
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COSMOPOLITAN_C_END_
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#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
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#endif /* COSMOPOLITAN_LIBC_STR_KNUTHMULTIPLICATIVEHASH_H_ */
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