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/* -*- 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>
# include "mozilla/Attributes.h"
/**
* 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:
constexpr MOZ_IMPLICIT char16ptr_t(const char16_t* aPtr) : mPtr(aPtr) {}
MOZ_IMPLICIT char16ptr_t(const wchar_t* aPtr)
: mPtr(reinterpret_cast<const char16_t*>(aPtr)) {}
/* Without this, nullptr assignment would be ambiguous. */
constexpr MOZ_IMPLICIT char16ptr_t(decltype(nullptr)) : mPtr(nullptr) {}
constexpr operator const char16_t*() const { return mPtr; }
operator const wchar_t*() const {
return reinterpret_cast<const wchar_t*>(mPtr);
}
operator wchar_t*() {
return const_cast<wchar_t*>(reinterpret_cast<const wchar_t*>(mPtr));
}
constexpr operator const void*() const { return mPtr; }
constexpr explicit operator bool() const { return mPtr != nullptr; }
/* Explicit cast operators to allow things like (char16_t*)str. */
constexpr 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 */
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