Bug 1867190 - Initialise the PHC allocate delay later r=glandium
[gecko.git] / mfbt / Char16.h
blob78568808304b7c93eeb84885fb8f4696f232656d
1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
7 /* Implements a UTF-16 character type. */
9 #ifndef mozilla_Char16_h
10 #define mozilla_Char16_h
12 #ifdef __cplusplus
15 * C++11 introduces a char16_t type and support for UTF-16 string and character
16 * literals. C++11's char16_t is a distinct builtin type. Technically, char16_t
17 * is a 16-bit code unit of a Unicode code point, not a "character".
20 # ifdef WIN32
21 # define MOZ_USE_CHAR16_WRAPPER
22 # include <cstdint>
23 # include "mozilla/Attributes.h"
24 /**
25 * Win32 API extensively uses wchar_t, which is represented by a separated
26 * builtin type than char16_t per spec. It's not the case for MSVC prior to
27 * MSVC 2015, but other compilers follow the spec. We want to mix wchar_t and
28 * char16_t on Windows builds. This class is supposed to make it easier. It
29 * stores char16_t const pointer, but provides implicit casts for wchar_t as
30 * well. On other platforms, we simply use
31 * |typedef const char16_t* char16ptr_t|. Here, we want to make the class as
32 * similar to this typedef, including providing some casts that are allowed
33 * by the typedef.
35 class char16ptr_t {
36 private:
37 const char16_t* mPtr;
38 static_assert(sizeof(char16_t) == sizeof(wchar_t),
39 "char16_t and wchar_t sizes differ");
41 public:
42 constexpr MOZ_IMPLICIT char16ptr_t(const char16_t* aPtr) : mPtr(aPtr) {}
43 MOZ_IMPLICIT char16ptr_t(const wchar_t* aPtr)
44 : mPtr(reinterpret_cast<const char16_t*>(aPtr)) {}
46 /* Without this, nullptr assignment would be ambiguous. */
47 constexpr MOZ_IMPLICIT char16ptr_t(decltype(nullptr)) : mPtr(nullptr) {}
49 constexpr operator const char16_t*() const { return mPtr; }
50 operator const wchar_t*() const {
51 return reinterpret_cast<const wchar_t*>(mPtr);
54 operator wchar_t*() {
55 return const_cast<wchar_t*>(reinterpret_cast<const wchar_t*>(mPtr));
58 constexpr operator const void*() const { return mPtr; }
59 constexpr explicit operator bool() const { return mPtr != nullptr; }
61 explicit operator int() const { return reinterpret_cast<intptr_t>(mPtr); }
62 explicit operator unsigned int() const {
63 return reinterpret_cast<uintptr_t>(mPtr);
65 explicit operator long() const { return reinterpret_cast<intptr_t>(mPtr); }
66 explicit operator unsigned long() const {
67 return reinterpret_cast<uintptr_t>(mPtr);
69 explicit operator long long() const {
70 return reinterpret_cast<intptr_t>(mPtr);
72 explicit operator unsigned long long() const {
73 return reinterpret_cast<uintptr_t>(mPtr);
76 /**
77 * Some Windows API calls accept BYTE* but require that data actually be
78 * WCHAR*. Supporting this requires explicit operators to support the
79 * requisite explicit casts.
81 explicit operator const char*() const {
82 return reinterpret_cast<const char*>(mPtr);
84 explicit operator const unsigned char*() const {
85 return reinterpret_cast<const unsigned char*>(mPtr);
87 explicit operator unsigned char*() const {
88 return const_cast<unsigned char*>(
89 reinterpret_cast<const unsigned char*>(mPtr));
91 explicit operator void*() const { return const_cast<char16_t*>(mPtr); }
93 /* Some operators used on pointers. */
94 char16_t operator[](size_t aIndex) const { return mPtr[aIndex]; }
95 bool operator==(const char16ptr_t& aOther) const {
96 return mPtr == aOther.mPtr;
98 bool operator==(decltype(nullptr)) const { return mPtr == nullptr; }
99 bool operator!=(const char16ptr_t& aOther) const {
100 return mPtr != aOther.mPtr;
102 bool operator!=(decltype(nullptr)) const { return mPtr != nullptr; }
103 char16ptr_t operator+(int aValue) const { return char16ptr_t(mPtr + aValue); }
104 char16ptr_t operator+(unsigned int aValue) const {
105 return char16ptr_t(mPtr + aValue);
107 char16ptr_t operator+(long aValue) const {
108 return char16ptr_t(mPtr + aValue);
110 char16ptr_t operator+(unsigned long aValue) const {
111 return char16ptr_t(mPtr + aValue);
113 char16ptr_t operator+(long long aValue) const {
114 return char16ptr_t(mPtr + aValue);
116 char16ptr_t operator+(unsigned long long aValue) const {
117 return char16ptr_t(mPtr + aValue);
119 ptrdiff_t operator-(const char16ptr_t& aOther) const {
120 return mPtr - aOther.mPtr;
124 inline decltype((char*)0 - (char*)0) operator-(const char16_t* aX,
125 const char16ptr_t aY) {
126 return aX - static_cast<const char16_t*>(aY);
129 # else
131 typedef const char16_t* char16ptr_t;
133 # endif
135 static_assert(sizeof(char16_t) == 2, "Is char16_t type 16 bits?");
136 static_assert(char16_t(-1) > char16_t(0), "Is char16_t type unsigned?");
137 static_assert(sizeof(u'A') == 2, "Is unicode char literal 16 bits?");
138 static_assert(sizeof(u""[0]) == 2, "Is unicode string char 16 bits?");
140 #endif
142 #endif /* mozilla_Char16_h */