mfbt/HashFunctions.cpp
author Nicholas Nethercote <nnethercote@mozilla.com>
Mon, 28 Sep 2015 21:11:52 -0700
changeset 302316 feb0f7522ece30fdcc264ccb8df5e580c4f27a07
parent 214333 91d7659bb35145e10ff737753688e0972c1a79b5
child 505383 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1209812 (part 1) - Remove casts between cairo_format_t and gfxImageFormat. r=nical. cairo_format_t and gfxImageFormat have their equivalent constants in the same order, so you can just cast between them, which is kind of nasty. This patch replaces all such casts with explicit conversions via calls to new conversion functions. These functions will be removed in a subsequent patch.

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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* aBytes, size_t aLength)
{
  uint32_t hash = 0;
  const char* b = reinterpret_cast<const char*>(aBytes);

  /* Walk word by word. */
  size_t i = 0;
  for (; i < aLength - (aLength % 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 < aLength; i++) {
    hash = AddToHash(hash, b[i]);
  }
  return hash;
}

} /* namespace mozilla */