mfbt/HashFunctions.cpp
author Chris Lord <chrislord.net@gmail.com>
Wed, 13 Mar 2013 18:51:03 +0000
changeset 132374 669a4b33fa4bad757d840b40e99b69132007d573
parent 119760 b511cc69f71774e42589f1fd843006d230e3cd13
child 210314 cf068fd95d3cef2e75205ae37c937bfaee01506f
permissions -rw-r--r--
Bug 850396 - Disable single-tile paint path in BasicTiledThebesLayer. r=bgirard a=lsblakk This code-path has always had issues, but the fix in bug 842389 causes them to be exposed more frequently.

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "mozilla/Types.h"

#include <string.h>

namespace mozilla {

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 */