/usr/include/mozjs-24/mozilla/PodOperations.h is in libmozjs-24-dev 24.2.0-3ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
/*
* Operations for zeroing POD types, arrays, and so on.
*
* These operations are preferable to memset, memcmp, and the like because they
* don't require remembering to multiply by sizeof(T), array lengths, and so on
* everywhere.
*/
#ifndef mozilla_PodOperations_h
#define mozilla_PodOperations_h
#include "mozilla/Attributes.h"
#include "mozilla/Util.h"
#include <string.h>
namespace mozilla {
/** Set the contents of |t| to 0. */
template<typename T>
static void
PodZero(T* t)
{
memset(t, 0, sizeof(T));
}
/** Set the contents of |nelem| elements starting at |t| to 0. */
template<typename T>
static void
PodZero(T* t, size_t nelem)
{
/*
* This function is often called with 'nelem' small; we use an inline loop
* instead of calling 'memset' with a non-constant length. The compiler
* should inline the memset call with constant size, though.
*/
for (T* end = t + nelem; t < end; t++)
memset(t, 0, sizeof(T));
}
/*
* Arrays implicitly convert to pointers to their first element, which is
* dangerous when combined with the above PodZero definitions. Adding an
* overload for arrays is ambiguous, so we need another identifier. The
* ambiguous overload is left to catch mistaken uses of PodZero; if you get a
* compile error involving PodZero and array types, use PodArrayZero instead.
*/
template<typename T, size_t N>
static void PodZero(T (&t)[N]) MOZ_DELETE;
template<typename T, size_t N>
static void PodZero(T (&t)[N], size_t nelem) MOZ_DELETE;
/** Set the contents of the array |t| to zero. */
template <class T, size_t N>
static void
PodArrayZero(T (&t)[N])
{
memset(t, 0, N * sizeof(T));
}
/**
* Assign |*src| to |*dst|. The locations must not be the same and must not
* overlap.
*/
template<typename T>
static void
PodAssign(T* dst, const T* src)
{
MOZ_ASSERT(dst != src);
MOZ_ASSERT_IF(src < dst, PointerRangeSize(src, static_cast<const T*>(dst)) >= 1);
MOZ_ASSERT_IF(dst < src, PointerRangeSize(static_cast<const T*>(dst), src) >= 1);
memcpy(reinterpret_cast<char*>(dst), reinterpret_cast<const char*>(src), sizeof(T));
}
/**
* Copy |nelem| T elements from |src| to |dst|. The two memory ranges must not
* overlap!
*/
template<typename T>
MOZ_ALWAYS_INLINE static void
PodCopy(T* dst, const T* src, size_t nelem)
{
MOZ_ASSERT(dst != src);
MOZ_ASSERT_IF(src < dst, PointerRangeSize(src, static_cast<const T*>(dst)) >= nelem);
MOZ_ASSERT_IF(dst < src, PointerRangeSize(static_cast<const T*>(dst), src) >= nelem);
if (nelem < 128) {
/*
* Avoid using operator= in this loop, as it may have been
* intentionally deleted by the POD type.
*/
for (const T* srcend = src + nelem; src < srcend; src++, dst++)
PodAssign(dst, src);
} else {
memcpy(dst, src, nelem * sizeof(T));
}
}
template<typename T>
MOZ_ALWAYS_INLINE static void
PodCopy(volatile T* dst, const volatile T* src, size_t nelem)
{
MOZ_ASSERT(dst != src);
MOZ_ASSERT_IF(src < dst,
PointerRangeSize(src, static_cast<const volatile T*>(dst)) >= nelem);
MOZ_ASSERT_IF(dst < src,
PointerRangeSize(static_cast<const volatile T*>(dst), src) >= nelem);
/*
* Volatile |dst| requires extra work, because it's undefined behavior to
* modify volatile objects using the mem* functions. Just write out the
* loops manually, using operator= rather than memcpy for the same reason,
* and let the compiler optimize to the extent it can.
*/
for (const volatile T* srcend = src + nelem; src < srcend; src++, dst++)
*dst = *src;
}
/*
* Copy the contents of the array |src| into the array |dst|, both of size N.
* The arrays must not overlap!
*/
template <class T, size_t N>
static void
PodArrayCopy(T (&dst)[N], const T (&src)[N])
{
PodCopy(dst, src, N);
}
/**
* Determine whether the |len| elements at |one| are memory-identical to the
* |len| elements at |two|.
*/
template<typename T>
MOZ_ALWAYS_INLINE static bool
PodEqual(const T* one, const T* two, size_t len)
{
if (len < 128) {
const T* p1end = one + len;
const T* p1 = one;
const T* p2 = two;
for (; p1 < p1end; p1++, p2++) {
if (*p1 != *p2)
return false;
}
return true;
}
return !memcmp(one, two, len * sizeof(T));
}
} // namespace mozilla
#endif // mozilla_PodOperations_h_
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