mfbt/HashFunctions.cpp
author Gregory Szorc <gps@mozilla.com>
Wed, 28 Jan 2015 13:37:00 -0800
branchCAL150_20120822_RELBRANCH
changeset 120235 3928db09ec452e0c55af3bb8be4abb93ad955ad1
parent 98529 f4157e8c410708d76703f19e4dfb61859bfe32d8
child 100672 1a0f4431003105008d31616e75b8db2d3291d54f
permissions -rw-r--r--
Close old release branch CAL150_20120822_RELBRANCH

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sw=4 et tw=99 ft=cpp:
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* Implementations of hash functions */

#include "mozilla/HashFunctions.h"
#include <string.h>

namespace mozilla {

MFBT_API(uint32_t)
HashBytes(const void* bytes, size_t length)
{
  uint32_t hash = 0;
  const char* b = reinterpret_cast<const char*>(bytes);

  /* Walk word by word. */
  size_t i = 0;
  for (; i < length - (length % sizeof(size_t)); i += sizeof(size_t)) {
    /* Do an explicitly unaligned load of the data. */
    size_t data;
    memcpy(&data, b + i, sizeof(size_t));

    hash = AddToHash(hash, data, sizeof(data));
  }

  /* Get the remaining bytes. */
  for (; i < length; i++) {
    hash = AddToHash(hash, b[i]);
  }

  return hash;
}

} /* namespace mozilla */