| // Copyright 2014 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Hashing algorithm inspired by |
| // wyhash: https://github.com/wangyi-fudan/wyhash/blob/ceb019b530e2c1c14d70b79bfa2bc49de7d95bc1/Modern%20Non-Cryptographic%20Hash%20Function%20and%20Pseudorandom%20Number%20Generator.pdf |
| |
| //go:build 386 || arm || mips || mipsle |
| |
| package runtime |
| |
| import "unsafe" |
| |
| func memhash32Fallback(p unsafe.Pointer, seed uintptr) uintptr { |
| a, b := mix32(uint32(seed), uint32(4^hashkey[0])) |
| t := readUnaligned32(p) |
| a ^= t |
| b ^= t |
| a, b = mix32(a, b) |
| a, b = mix32(a, b) |
| return uintptr(a ^ b) |
| } |
| |
| func memhash64Fallback(p unsafe.Pointer, seed uintptr) uintptr { |
| a, b := mix32(uint32(seed), uint32(8^hashkey[0])) |
| a ^= readUnaligned32(p) |
| b ^= readUnaligned32(add(p, 4)) |
| a, b = mix32(a, b) |
| a, b = mix32(a, b) |
| return uintptr(a ^ b) |
| } |
| |
| func memhashFallback(p unsafe.Pointer, seed, s uintptr) uintptr { |
| |
| a, b := mix32(uint32(seed), uint32(s^hashkey[0])) |
| if s == 0 { |
| return uintptr(a ^ b) |
| } |
| for ; s > 8; s -= 8 { |
| a ^= readUnaligned32(p) |
| b ^= readUnaligned32(add(p, 4)) |
| a, b = mix32(a, b) |
| p = add(p, 8) |
| } |
| if s >= 4 { |
| a ^= readUnaligned32(p) |
| b ^= readUnaligned32(add(p, s-4)) |
| } else { |
| t := uint32(*(*byte)(p)) |
| t |= uint32(*(*byte)(add(p, s>>1))) << 8 |
| t |= uint32(*(*byte)(add(p, s-1))) << 16 |
| b ^= t |
| } |
| a, b = mix32(a, b) |
| a, b = mix32(a, b) |
| return uintptr(a ^ b) |
| } |
| |
| func mix32(a, b uint32) (uint32, uint32) { |
| c := uint64(a^uint32(hashkey[1])) * uint64(b^uint32(hashkey[2])) |
| return uint32(c), uint32(c >> 32) |
| } |
