84 lines
1.9 KiB
C
84 lines
1.9 KiB
C
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#define PRIME64_1 11400714785074694791ULL
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#define PRIME64_2 14029467366897019727ULL
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#define PRIME64_3 1609587929392839161ULL
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#define PRIME64_4 9650029242287828579ULL
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#define PRIME64_5 2870177450012600261ULL
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static inline u64 xx_hash(u64 x) {
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u64 h64 = PRIME64_5 + 8;
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h64 += x * PRIME64_3;
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h64 = ((h64 << 23) | (h64 >> (64 - 23))) * PRIME64_2 + PRIME64_4;
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h64 ^= h64 >> 33;
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h64 *= PRIME64_2;
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h64 ^= h64 >> 29;
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h64 *= PRIME64_3;
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h64 ^= h64 >> 32;
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return h64;
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}
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static inline u64 city_hash(string s) {
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const u64 k = 0x9ddfea08eb382d69ULL;
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u64 a = s.count;
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u64 b = s.count * 5;
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u64 c = 9;
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u64 d = b;
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if (s.count <= 16) {
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memcpy(&a, s.data, sizeof(u64));
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memcpy(&b, s.data + s.count - 8, sizeof(u64));
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} else {
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memcpy(&a, s.data, sizeof(u64));
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memcpy(&b, s.data + 8, sizeof(u64));
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memcpy(&c, s.data + s.count - 8, sizeof(u64));
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memcpy(&d, s.data + s.count - 16, sizeof(u64));
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}
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a += b;
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a = (a << 43) | (a >> (64 - 43));
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a += c;
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a = a * 5 + 0x52dce729;
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d ^= a;
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d = (d << 44) | (d >> (64 - 44));
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d += b;
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return d * k;
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}
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u64 djb2_hash(string s) {
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u64 hash = 5381;
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for (u64 i = 0; i < s.count; i++) {
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hash = ((hash << 5) + hash) + s.data[i];
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}
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return hash;
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}
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u64 string_get_hash(string s) {
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if (s.count > 32) return djb2_hash(s);
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return city_hash(s);
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}
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u64 pointer_get_hash(void *p) {
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return xx_hash((u64)p);
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}
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u64 float64_get_hash(float64 x) {
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return xx_hash(*(u64*)&x);
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}
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u64 float32_get_hash(float32 x) {
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return float64_get_hash((float64)x);
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}
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#define get_hash(x) _Generic((x), \
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string: string_get_hash, \
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s8: xx_hash, \
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u8: xx_hash, \
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s16: xx_hash, \
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u16: xx_hash, \
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s32: xx_hash, \
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u32: xx_hash, \
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s64: xx_hash, \
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u64: xx_hash, \
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f32: float32_get_hash, \
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f64: float64_get_hash, \
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default: pointer_get_hash \
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)(x)
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