// bslalg_arraydestructionprimitives.h -*-C++-*-
#ifndef INCLUDED_BSLALG_ARRAYDESTRUCTIONPRIMITIVES
#define INCLUDED_BSLALG_ARRAYDESTRUCTIONPRIMITIVES
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
//@PURPOSE: Provide primitive algorithms that destroy arrays.
//
//@CLASSES:
// bslalg::ArrayDestructionPrimitives: namespace for array algorithms
//
//@SEE_ALSO: bslma_destructionutil, bslma_constructionutil
//
//@DESCRIPTION: This component provides utilities to destroy arrays with a
// uniform interface, but selecting a different implementation according to the
// traits possessed by the underlying type.
//
// The traits under consideration by this component are:
//..
// Trait Note
// ----- -------------------------------------
// bsl::is_trivially_copyable Expressed in English as "TYPE has the
// bit-wise copyable trait", or "TYPE is
// bit-wise copyable", this trait also
// implies that destructor calls can be
// elided with no effect on observable
// behavior.
//
//..
//
///Usage
///-----
// TBD: maybe fix up usage example to show with allocator
// In this section we show intended use of this component. Note that this
// component is for use by the 'bslstl' package. Other clients should use the
// STL algorithms (in header '<algorithm>' and '<memory>').
//
///Example 1: Destroy Arrays of 'int' and 'Integer' Wrapper Objects
/// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// In this example, we will use 'bslalg::ArrayDestructionPrimitives' to destroy
// both an array of integer scalars and an array of 'MyInteger' objects.
// Calling the 'destroy' method on an array of integers is a no-op while
// calling the 'destroy' method on an array of objects of 'MyInteger' class
// invokes the destructor of each of the objects in the array.
//
// First, we define a 'MyInteger' class that contains an integer value:
//..
// class MyInteger {
// // This class represents an integer value.
//
// int d_intValue; // integer value
//
// public:
// // CREATORS
// MyInteger();
// // Create a 'MyInteger' object having integer value '0'.
//
// explicit MyInteger(int value);
// // Create a 'MyInteger' object having the specified 'value'.
//
// ~MyInteger();
// // Destroy this object.
//
// // ACCESSORS
// int getValue() const;
// // Return the integer value contained in this object.
// };
//..
// Then, we create an array of objects, 'myIntegers', of type 'MyInteger' (note
// that we 'bsls::ObjectBuffer' to allow us to safely invoke the destructor
// explicitly):
//..
// bsls::ObjectBuffer<MyInteger> arrayBuffer[5];
// MyInteger *myIntegers = &arrayBuffer[0].object();
// for (int i = 0;i < 5; ++i) {
// new (myIntegers + i) MyInteger(i);
// }
//..
// Now, we define a primitive integer array:
//..
// int scalarIntegers[] = { 0, 1, 2, 3, 4 };
//..
// Finally, we use the uniform 'bslalg::ArrayDestructionPrimitives:destroy'
// method to destroy both 'myIntegers' and 'scalarIntegers':
//..
// bslalg::ArrayDestructionPrimitives::destroy(myIntegers, myIntegers + 5);
// bslalg::ArrayDestructionPrimitives::destroy(scalarIntegers,
// scalarIntegers + 5);
//..
#include <bslscm_version.h>
#include <bsls_assert.h>
#include <bsls_types.h>
#include <bslma_allocatortraits.h>
#include <bslmf_istriviallycopyable.h>
#include <cstddef> // 'size_t'
#include <cstring> // 'memset', 'memcpy', and 'memmove'
namespace BloombergLP {
namespace bslalg {
// =================================
// struct ArrayDestructionPrimitives
// =================================
struct ArrayDestructionPrimitives {
// This 'struct' provides a namespace for a suite of utility functions that
// destroy arrays of elements of the parameterized type 'TARGET_TYPE'.
// Depending on the traits of 'TARGET_TYPE', the destructor may be invoked,
// or not (optimized away by no-op).
// PRIVATE CLASS METHODS
template <class TARGET_TYPE, class ALLOCATOR>
static void destroy(TARGET_TYPE *begin,
TARGET_TYPE *end,
ALLOCATOR allocator,
bsl::true_type);
template <class TARGET_TYPE, class ALLOCATOR>
static void destroy(TARGET_TYPE *begin,
TARGET_TYPE *end,
ALLOCATOR allocator,
bsl::false_type);
// Destroy each instance of 'TARGET_TYPE' in the array beginning at the
// specified 'begin' address and ending immediately before the
// specified 'end' address, using the specified 'allocator'. Elide the
// use of the destructor entirely if (template parameter) 'TARGET_TYPE'
// is trivially copyable, i.e., in the overload where the last argument
// (used only for overload resolution) is of type 'bsl::true_type'.
template <class TARGET_TYPE>
static void destroy(TARGET_TYPE *begin, TARGET_TYPE *end, bsl::true_type);
template <class TARGET_TYPE>
static void destroy(TARGET_TYPE *begin, TARGET_TYPE *end, bsl::false_type);
// Destroy each instance of 'TARGET_TYPE' in the array beginning at the
// specified 'begin' address and ending immediately before the
// specified 'end' address. Elide the use of the destructor entirely
// if (template parameter) 'TARGET_TYPE' is trivially copyable, i.e.
// in the overload where the last argument (used only for overload
// resolution) if of type 'bsl::true_type'.
public:
// CLASS METHODS
template <class TARGET_TYPE, class ALLOCATOR>
static void
destroy(TARGET_TYPE *begin, TARGET_TYPE *end, ALLOCATOR allocator);
// Destroy the elements in the segment of an array of parameterized
// 'TARGET_TYPE' beginning at the specified 'begin' address and ending
// immediately before the specified 'end' address, using the specified
// 'allocator'. If 'begin == 0' and 'end == 0' this function has no
// effect. The behavior is undefined unless either (1) 'begin <= end',
// 'begin != 0', and 'end != 0', or (2) 'begin == 0 && end == 0'. Note
// that this method does not deallocate any memory (except memory
// deallocated by the element destructor calls).
template <class TARGET_TYPE>
static void destroy(TARGET_TYPE *begin, TARGET_TYPE *end);
// Destroy of the elements in the segment of an array of parameterized
// 'TARGET_TYPE' beginning at the specified 'begin' address and ending
// immediately before the specified 'end' address. If 'begin == 0' and
// 'end == 0' this function has no effect. The behavior is undefined
// unless either (1) 'begin <= end', 'begin != 0', and 'end != 0', or
// (2) 'begin == 0 && end == 0'. Note that this method does not
// deallocate any memory (except memory deallocated by the element
// destructor calls).
};
// ============================================================================
// INLINE FUNCTION DEFINITIONS
// ============================================================================
// ---------------------------------
// struct ArrayDestructionPrimitives
// ---------------------------------
// PRIVATE CLASS METHODS
template <class TARGET_TYPE, class ALLOCATOR>
inline
void ArrayDestructionPrimitives::destroy(TARGET_TYPE *begin,
TARGET_TYPE *end,
ALLOCATOR,
bsl::true_type)
{
// 'bsl::is_trivially_copyable' is a valid surrogate for having a trivial
// destructor.
#ifdef BSLS_ASSERT_SAFE_IS_ACTIVE
if (begin) {
std::memset((void *) begin, 0xa5, (end - begin) * sizeof(TARGET_TYPE));
}
#else
(void) begin;
(void) end;
#endif
}
template <class TARGET_TYPE, class ALLOCATOR>
void ArrayDestructionPrimitives::destroy(TARGET_TYPE *begin,
TARGET_TYPE *end,
ALLOCATOR allocator,
bsl::false_type)
{
for (; begin != end; ++begin) {
bsl::allocator_traits<ALLOCATOR>::destroy(allocator, begin);
}
}
template <class TARGET_TYPE>
inline
void ArrayDestructionPrimitives::destroy(TARGET_TYPE *begin,
TARGET_TYPE *end,
bsl::true_type)
{
// 'bsl::is_trivially_copyable' is a valid surrogate for having a trivial
// destructor.
#ifdef BSLS_ASSERT_SAFE_IS_ACTIVE
bsls::Types::size_type numBytes = (const char*)end - (const char*)begin;
std::memset((void *)begin, 0xa5, numBytes);
#else
(void) begin;
(void) end;
#endif
}
template <class TARGET_TYPE>
void ArrayDestructionPrimitives::destroy(TARGET_TYPE *begin,
TARGET_TYPE *end,
bsl::false_type)
{
for (; begin != end; ++begin) {
begin->~TARGET_TYPE();
}
}
// CLASS METHODS
template <class TARGET_TYPE, class ALLOCATOR>
inline
void ArrayDestructionPrimitives::destroy(TARGET_TYPE *begin,
TARGET_TYPE *end,
ALLOCATOR allocator)
{
BSLS_ASSERT_SAFE(begin || !end);
BSLS_ASSERT_SAFE(end || !begin);
BSLS_ASSERT_SAFE(begin <= end);
destroy(begin,
end,
allocator,
typename bsl::is_trivially_copyable<TARGET_TYPE>::type());
}
template <class TARGET_TYPE>
inline
void ArrayDestructionPrimitives::destroy(TARGET_TYPE *begin,
TARGET_TYPE *end)
{
BSLS_ASSERT_SAFE(begin || !end);
BSLS_ASSERT_SAFE(end || !begin);
BSLS_ASSERT_SAFE(begin <= end);
destroy(begin,
end,
typename bsl::is_trivially_copyable<TARGET_TYPE>::type());
}
} // close package namespace
#ifndef BDE_OPENSOURCE_PUBLICATION // BACKWARD_COMPATIBILITY
// ============================================================================
// BACKWARD COMPATIBILITY
// ============================================================================
typedef bslalg::ArrayDestructionPrimitives bslalg_ArrayDestructionPrimitives;
// This alias is defined for backward compatibility.
#endif // BDE_OPENSOURCE_PUBLICATION -- BACKWARD_COMPATIBILITY
} // close enterprise namespace
#endif
// ----------------------------------------------------------------------------
// Copyright 2013 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------