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/. */
8
* Miscellaneous uncategorized functionality. Please add new functionality to
9
* new headers, or to other appropriate existing headers, not here.
12
#ifndef mozilla_Util_h
13
#define mozilla_Util_h
15
#include "mozilla/Assertions.h"
16
#include "mozilla/Attributes.h"
17
#include "mozilla/Types.h"
21
#include "mozilla/Alignment.h"
26
* Safely subtract two pointers when it is known that end >= begin. This avoids
27
* the common compiler bug that if (size_t(end) - size_t(begin)) has the MSB
28
* set, the unsigned subtraction followed by right shift will produce -1, or
29
* size_t(-1), instead of the real difference.
32
MOZ_ALWAYS_INLINE size_t
33
PointerRangeSize(T* begin, T* end)
35
MOZ_ASSERT(end >= begin);
36
return (size_t(end) - size_t(begin)) / sizeof(T);
40
* Compute the length of an array with constant length. (Use of this method
41
* with a non-array pointer will not compile.)
43
* Beware of the implicit trailing '\0' when using this with string constants.
45
template<typename T, size_t N>
47
ArrayLength(T (&arr)[N])
53
* Compute the address one past the last element of a constant-length array.
55
* Beware of the implicit trailing '\0' when using this with string constants.
57
template<typename T, size_t N>
61
return arr + ArrayLength(arr);
64
} /* namespace mozilla */
66
#endif /* __cplusplus */
69
* MOZ_ARRAY_LENGTH() is an alternative to mozilla::ArrayLength() for C files
70
* that can't use C++ template functions and for static_assert() calls that
71
* can't call ArrayLength() when it is not a C++11 constexpr function.
73
#ifdef MOZ_HAVE_CXX11_CONSTEXPR
74
# define MOZ_ARRAY_LENGTH(array) mozilla::ArrayLength(array)
76
# define MOZ_ARRAY_LENGTH(array) (sizeof(array)/sizeof((array)[0]))
79
#endif /* mozilla_Util_h */