100 lines
2.7 KiB
V
100 lines
2.7 KiB
V
module fnv1a
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// This module implements a FNV-1a hash.
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// (see https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function)
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const (
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fnv64_prime = u64(1099511628211)
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fnv64_offset_basis = u64(14695981039346656037)
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fnv32_offset_basis = u32(2166136261)
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fnv32_prime = u32(16777619)
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)
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// sum32 returns a fnv1a hash of the string, described by `data`
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[direct_array_access; inline]
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pub fn sum32_string(data string) u32 {
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mut hash := fnv1a.fnv32_offset_basis
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for i in 0 .. data.len {
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hash = (hash ^ u32(data[i])) * fnv1a.fnv32_prime
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}
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return hash
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}
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// sum32 returns a fnv1a hash of the memory block, described by the dynamic
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// byte array `data`.
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[direct_array_access; inline]
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pub fn sum32(data []byte) u32 {
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mut hash := fnv1a.fnv32_offset_basis
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for i in 0 .. data.len {
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hash = (hash ^ u32(data[i])) * fnv1a.fnv32_prime
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}
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return hash
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}
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// sum32_bytes returns a fnv1a hash of the struct `s`.
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[direct_array_access; inline]
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pub fn sum32_struct<T>(s &T) u32 {
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bp := unsafe { &u8(s) }
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sz := int(sizeof(T))
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mut hash := fnv1a.fnv32_offset_basis
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for i in 0 .. sz {
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hash = unsafe { (hash ^ u32(bp[i])) * fnv1a.fnv32_prime }
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}
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return hash
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}
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// sum32_bytes returns a fnv1a hash of `data_len` bytes starting at
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// the address in the given &byte pointer `data`.
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[direct_array_access; inline; unsafe]
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pub fn sum32_bytes(data &byte, data_len int) u32 {
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mut hash := fnv1a.fnv32_offset_basis
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for i in 0 .. data_len {
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hash = unsafe { (hash ^ u32(data[i])) * fnv1a.fnv32_prime }
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}
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return hash
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}
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// sum64 returns a fnv1a hash of the string, described by `data`
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[direct_array_access; inline]
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pub fn sum64_string(data string) u64 {
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mut hash := fnv1a.fnv64_offset_basis
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for i in 0 .. data.len {
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hash = (hash ^ u64(data[i])) * fnv1a.fnv64_prime
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}
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return hash
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}
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// sum64 returns a fnv1a hash of the memory block, described by the dynamic
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// byte array `data`.
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[direct_array_access; inline]
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pub fn sum64(data []byte) u64 {
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mut hash := fnv1a.fnv64_offset_basis
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for i in 0 .. data.len {
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hash = (hash ^ u64(data[i])) * fnv1a.fnv64_prime
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}
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return hash
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}
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// sum64_bytes returns a fnv1a hash of `data_len` bytes starting at
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// the address in the given &byte pointer `data`.
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[direct_array_access; inline; unsafe]
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pub fn sum64_bytes(data &byte, data_len int) u64 {
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mut hash := fnv1a.fnv64_offset_basis
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for i in 0 .. data_len {
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hash = unsafe { (hash ^ u64(data[i])) * fnv1a.fnv64_prime }
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}
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return hash
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}
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// sum64_bytes returns a fnv1a hash of the struct `s`.
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[direct_array_access; inline]
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pub fn sum64_struct<T>(s &T) u64 {
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bp := unsafe { &u8(s) }
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sz := int(sizeof(T))
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mut hash := fnv1a.fnv64_offset_basis
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for i in 0 .. sz {
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hash = unsafe { (hash ^ u64(bp[i])) * fnv1a.fnv64_prime }
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}
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return hash
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}
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