/* -*- 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/. */ /* Implements a UTF-16 character type. */ #ifndef mozilla_Char16_h #define mozilla_Char16_h #ifdef __cplusplus /* * C++11 introduces a char16_t type and support for UTF-16 string and character * literals. C++11's char16_t is a distinct builtin type. Technically, char16_t * is a 16-bit code unit of a Unicode code point, not a "character". */ #ifdef WIN32 # define MOZ_USE_CHAR16_WRAPPER # include <cstdint> /** * Win32 API extensively uses wchar_t, which is represented by a separated * builtin type than char16_t per spec. It's not the case for MSVC prior to * MSVC 2015, but other compilers follow the spec. We want to mix wchar_t and * char16_t on Windows builds. This class is supposed to make it easier. It * stores char16_t const pointer, but provides implicit casts for wchar_t as * well. On other platforms, we simply use * |typedef const char16_t* char16ptr_t|. Here, we want to make the class as * similar to this typedef, including providing some casts that are allowed * by the typedef. */ class char16ptr_t { private: const char16_t* mPtr; static_assert(sizeof(char16_t) == sizeof(wchar_t), "char16_t and wchar_t sizes differ"); public: char16ptr_t(const char16_t* aPtr) : mPtr(aPtr) {} char16ptr_t(const wchar_t* aPtr) : mPtr(reinterpret_cast<const char16_t*>(aPtr)) {} /* Without this, nullptr assignment would be ambiguous. */ constexpr char16ptr_t(decltype(nullptr)) : mPtr(nullptr) {} operator const char16_t*() const { return mPtr; } operator const wchar_t*() const { return reinterpret_cast<const wchar_t*>(mPtr); } operator const void*() const { return mPtr; } operator bool() const { return mPtr != nullptr; } /* Explicit cast operators to allow things like (char16_t*)str. */ explicit operator char16_t*() const { return const_cast<char16_t*>(mPtr); } explicit operator wchar_t*() const { return const_cast<wchar_t*>(static_cast<const wchar_t*>(*this)); } explicit operator int() const { return reinterpret_cast<intptr_t>(mPtr); } explicit operator unsigned int() const { return reinterpret_cast<uintptr_t>(mPtr); } explicit operator long() const { return reinterpret_cast<intptr_t>(mPtr); } explicit operator unsigned long() const { return reinterpret_cast<uintptr_t>(mPtr); } explicit operator long long() const { return reinterpret_cast<intptr_t>(mPtr); } explicit operator unsigned long long() const { return reinterpret_cast<uintptr_t>(mPtr); } /** * Some Windows API calls accept BYTE* but require that data actually be * WCHAR*. Supporting this requires explicit operators to support the * requisite explicit casts. */ explicit operator const char*() const { return reinterpret_cast<const char*>(mPtr); } explicit operator const unsigned char*() const { return reinterpret_cast<const unsigned char*>(mPtr); } explicit operator unsigned char*() const { return const_cast<unsigned char*>(reinterpret_cast<const unsigned char*>(mPtr)); } explicit operator void*() const { return const_cast<char16_t*>(mPtr); } /* Some operators used on pointers. */ char16_t operator[](size_t aIndex) const { return mPtr[aIndex]; } bool operator==(const char16ptr_t& aOther) const { return mPtr == aOther.mPtr; } bool operator==(decltype(nullptr)) const { return mPtr == nullptr; } bool operator!=(const char16ptr_t& aOther) const { return mPtr != aOther.mPtr; } bool operator!=(decltype(nullptr)) const { return mPtr != nullptr; } char16ptr_t operator+(int aValue) const { return char16ptr_t(mPtr + aValue); } char16ptr_t operator+(unsigned int aValue) const { return char16ptr_t(mPtr + aValue); } char16ptr_t operator+(long aValue) const { return char16ptr_t(mPtr + aValue); } char16ptr_t operator+(unsigned long aValue) const { return char16ptr_t(mPtr + aValue); } char16ptr_t operator+(long long aValue) const { return char16ptr_t(mPtr + aValue); } char16ptr_t operator+(unsigned long long aValue) const { return char16ptr_t(mPtr + aValue); } ptrdiff_t operator-(const char16ptr_t& aOther) const { return mPtr - aOther.mPtr; } }; inline decltype((char*)0-(char*)0) operator-(const char16_t* aX, const char16ptr_t aY) { return aX - static_cast<const char16_t*>(aY); } #else typedef const char16_t* char16ptr_t; #endif static_assert(sizeof(char16_t) == 2, "Is char16_t type 16 bits?"); static_assert(char16_t(-1) > char16_t(0), "Is char16_t type unsigned?"); static_assert(sizeof(u'A') == 2, "Is unicode char literal 16 bits?"); static_assert(sizeof(u""[0]) == 2, "Is unicode string char 16 bits?"); #endif #endif /* mozilla_Char16_h */