c3c/lib/std/hash/fnv64a.c3

// Copyright (c) 2021 Christoffer Lerno. All rights reserved.
// Use of this source code is governed by the MIT license
// a copy of which can be found in the LICENSE_STDLIB file.
module std::hash::fnv64a;

def Fnv64a = distinct ulong;

const FNV64A_START @private = 0xcbf29ce484222325;
const FNV64A_MUL @private = 0x00000100000001b3;

macro void @update(ulong &h, char x) @private => h = (h * FNV64A_MUL) ^ x;

fn void Fnv64a.init(&this)
{
    *this = FNV64A_START;
}

fn void Fnv64a.update(&this, char[] data)
{
	ulong h = (ulong)*this;
	foreach (char x : data)
    {
        @update(h, x);
    }
    *this = (Fnv64a)h;
}

macro void Fnv64a.update_char(&this, char c)
{
	@update(*this, x);
}

fn ulong encode(char[] data)
{
	ulong h = FNV64A_START;
	foreach (char x : data)
    {
		@update(h, x);
    }
    return h;
}