/* -*- 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/. */

#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)) {

      continue;

    }

    Maybe<char32_t> maybeCodePoint =

      DecodeOneUtf8CodePoint(Utf8Unit(c), &s, limit);

    if (maybeCodePoint.isNothing()) {

      return false;

    }

  }

  MOZ_ASSERT(s == limit);

  return true;

}