author Sam Sneddon <>
Tue, 05 Mar 2019 12:19:18 +0000
changeset 464592 ed02da4c6be28b064d9c6168f54c7f84036fa9e1
parent 448947 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1486514 [wpt PR 12695] - Make reftests 800x600 everywhere, a=testonly Automatic update from web-platform-tests Change reftest size to 800x600 everywhere (#12695) With Firefox, with the internal reftest runner (used by default), this doesn't actually change the reftest size in Firefox versions prior to 66 (currently on the beta channel); to get the correct behaviour with older versions of Firefox, you must pass `--reftest-external` to use the external reftest runner. -- wpt-commits: d5f07ed3b5186e553940a3d5c547067850a4e3f0 wpt-pr: 12695

/* -*- 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 */

#include "mozilla/Maybe.h"
#include "mozilla/TextUtils.h"
#include "mozilla/Types.h"
#include "mozilla/Utf8.h"

#include <stddef.h>
#include <stdint.h>

MFBT_API bool mozilla::IsValidUtf8(const void* aCodeUnits, size_t aCount) {
  const auto* s = static_cast<const unsigned char*>(aCodeUnits);
  const auto* const limit = s + aCount;

  while (s < limit) {
    unsigned char c = *s++;

    // If the first byte is ASCII, it's the only one in the code point.  Have a
    // fast path that avoids all the rest of the work and looping in that case.
    if (IsAscii(c)) {

    Maybe<char32_t> maybeCodePoint =
        DecodeOneUtf8CodePoint(Utf8Unit(c), &s, limit);
    if (maybeCodePoint.isNothing()) {
      return false;

  MOZ_ASSERT(s == limit);
  return true;