// bslstl_setcomparator.h -*-C++-*-
#ifndef INCLUDED_BSLSTL_SETCOMPARATOR
#define INCLUDED_BSLSTL_SETCOMPARATOR
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
//@PURPOSE: Provide a comparator for 'TreeNode' objects and a lookup key.
//
//@CLASSES:
// bslstl::SetComparator: comparator for 'TreeNode' objects and key objects
//
//@SEE_ALSO: bslstl_set, bslstl_treenode, bslalg_rbtreeutil
//
//@DESCRIPTION: This component provides a functor adapter, 'SetComparator',
// that adapts a parameterized 'COMPARATOR' comparing objects of a
// parameterized 'KEY' type into a functor comparing a object of 'KEY' type
// with a object of 'bslstl::TreeNode' type holding a object of 'KEY' type.
// Note that this functor was designed to be supplied to functions in
// 'bslalg::RbTreeUtil' primarily for the purpose of implementing a 'set'
// container.
//
///Usage
///-----
// This section illustrates intended use of this component.
//
///Example 1: Create a Simple Tree of 'TreeNode' Objects
///- - - - - - - - - - - - - - - - - - - - - - - - - - -
// Suppose that we want to create a tree of 'TreeNode' objects arranged
// according to a functor that we supply.
//
// First, we create an array of 'bslstl::TreeNode' objects, each holding a pair
// of integers:
//..
// typedef bsl::allocator<TreeNode<int> > Alloc;
//
// bslma::TestAllocator oa;
// Alloc allocator(&oa);
//
// enum { NUM_NODES = 5 };
//
// TreeNode<int>* nodes[NUM_NODES];
//
// for (int i = 0; i < NUM_NODES; ++i) {
// nodes[i] = allocator.allocate(1);
// nodes[i]->value() = i;
// }
//..
// Then, we define a 'SetComparator' object, 'comparator', for comparing
// 'bslstl::TreeNode<int>' objects with integers.
//..
// SetComparator<int, std::less<int> > comparator;
//..
// Now, we can use the functions in 'bslalg::RbTreeUtil' to arrange our tree:
//..
// bslalg::RbTreeAnchor tree;
//
// for (int i = 0; i < NUM_NODES; ++i) {
// int comparisonResult;
// bslalg::RbTreeNode *insertLocation =
// bslalg::RbTreeUtil::findUniqueInsertLocation(
// &comparisonResult,
// &tree,
// comparator,
// nodes[i]->value());
//
// assert(0 != comparisonResult);
//
// bslalg::RbTreeUtil::insertAt(&tree,
// insertLocation,
// comparisonResult < 0,
// nodes[i]);
// }
//
// assert(5 == tree.numNodes());
//..
// Then, we use 'bslalg::RbTreeUtil::next()' to navigate the elements of the
// tree, printing their values:
//..
// const bslalg::RbTreeNode *nodeIterator = tree.firstNode();
//
// while (nodeIterator != tree.sentinel()) {
// printf("Node value: %d\n",
// static_cast<const TreeNode<int> *>(nodeIterator)->value());
// nodeIterator = bslalg::RbTreeUtil::next(nodeIterator);
// }
//..
// Next, we destroy and deallocate each of the 'bslstl::TreeNode' objects:
//..
// for (int i = 0; i < NUM_NODES; ++i) {
// allocator.deallocate(nodes[i], 1);
// }
//..
// Finally, we observe the console output:
//..
// Node value: 0
// Node value: 1
// Node value: 2
// Node value: 3
// Node value: 4
//..
#include <bslscm_version.h>
#include <bslstl_pair.h>
#include <bslstl_treenode.h>
#include <bslalg_functoradapter.h>
#include <bslalg_swaputil.h>
#include <bslmf_movableref.h>
#include <bsls_platform.h>
#include <bsls_util.h>
namespace BloombergLP {
namespace bslstl {
// ===================
// class SetComparator
// ===================
template <class KEY, class COMPARATOR>
#ifdef BSLS_PLATFORM_CMP_MSVC
// Visual studio compiler fails to resolve the conversion operator in
// 'bslalg::FunctorAdapter_FunctionPointer' when using private inheritance.
// Below is a workaround until a more suitable way the resolve this issue can
// be found.
class SetComparator : public bslalg::FunctorAdapter<COMPARATOR>::Type {
#else
class SetComparator : private bslalg::FunctorAdapter<COMPARATOR>::Type {
#endif
// This class overloads the function-call operator to compare a referenced
// 'bslalg::RbTreeNode' object with a object of the parameterized 'KEY'
// type, assuming the reference to 'bslalg::RbTreeNode' is a base of a
// 'bslstl::TreeNode' holding an integer, using a functor of the
// parameterized 'COMPARATOR' type.
private:
// This class does not support assignment.
SetComparator& operator=(const SetComparator&); // Declared but not
// defined
public:
// TYPES
typedef TreeNode<KEY> NodeType;
// This alias represents the type of node holding a 'KEY' object.
// CREATORS
SetComparator();
// Create a 'SetComparator' object that will use a default constructed
// 'COMPARATOR'.
explicit SetComparator(const COMPARATOR& keyComparator);
// Create a 'SetComparator' object holding a copy of the specified
// 'keyComparator'.
// SetComparator(const SetComparator&) = default;
// Create a 'SapComparator' object with the 'COMPARATOR' object of the
// specified 'original' object.
// ~SapComparator() = default;
// Destroy this object.
// MANIPULATORS
template <class LOOKUP_KEY>
bool operator()(const LOOKUP_KEY& lhs,
const bslalg::RbTreeNode& rhs);
// Return 'true' if the specified 'lhs' is less than (ordered before,
// according to the comparator held by this object) 'value()' of the
// specified 'rhs' after being cast to 'NodeType', and 'false'
// otherwise. The behavior is undefined unless 'rhs' can be safely
// cast to 'NodeType'.
template <class LOOKUP_KEY>
bool operator()(const bslalg::RbTreeNode& lhs,
const LOOKUP_KEY& rhs);
// Return 'true' if 'value()' of the specified 'lhs' after
// being cast to 'NodeType' is less than (ordered before, according to
// the comparator held by this object) the specified 'rhs', and 'false'
// otherwise. The behavior is undefined unless 'rhs' can be safely
// cast to 'NodeType'.
void swap(SetComparator& other);
// Efficiently exchange the value of this object with the value of the
// specified 'other' object. This method provides the no-throw
// exception-safety guarantee.
// ACCESSORS
template <class LOOKUP_KEY>
bool operator()(const LOOKUP_KEY& lhs,
const bslalg::RbTreeNode& rhs) const;
// Return 'true' if the specified 'lhs' is less than (ordered before,
// according to the comparator held by this object) 'value()' of the
// specified 'rhs' after being cast to 'NodeType', and 'false'
// otherwise. The behavior is undefined unless 'rhs' can be safely
// cast to 'NodeType'.
template <class LOOKUP_KEY>
bool operator()(const bslalg::RbTreeNode& lhs,
const LOOKUP_KEY& rhs) const;
// Return 'true' if 'value()' of the specified 'lhs' after
// being cast to 'NodeType' is less than (ordered before, according to
// the comparator held by this object) the specified 'rhs', and 'false'
// otherwise. The behavior is undefined unless 'rhs' can be safely
// cast to 'NodeType'.
COMPARATOR& keyComparator();
// Return a reference providing modifiable access to the function
// pointer or functor to which this comparator delegates comparison
// operations.
const COMPARATOR& keyComparator() const;
// Return a reference providing non-modifiable access to the function
// pointer or functor to which this comparator delegates comparison
// operations.
};
// FREE FUNCTIONS
template <class KEY, class COMPARATOR>
void swap(SetComparator<KEY, COMPARATOR>& a,
SetComparator<KEY, COMPARATOR>& b);
// Efficiently exchange the values of the specified 'a' and 'b' objects.
// This function provides the no-throw exception-safety guarantee.
// ============================================================================
// TEMPLATE AND INLINE FUNCTION DEFINITIONS
// ============================================================================
// -------------------
// class SetComparator
// -------------------
// CREATORS
template <class KEY, class COMPARATOR>
inline
SetComparator<KEY, COMPARATOR>::SetComparator()
: bslalg::FunctorAdapter<COMPARATOR>::Type()
{
}
template <class KEY, class COMPARATOR>
inline
SetComparator<KEY, COMPARATOR>::
SetComparator(const COMPARATOR& valueComparator)
: bslalg::FunctorAdapter<COMPARATOR>::Type(valueComparator)
{
}
// MANIPULATORS
template <class KEY, class COMPARATOR>
template <class LOOKUP_KEY>
inline
bool SetComparator<KEY, COMPARATOR>::operator()(
const LOOKUP_KEY& lhs,
const bslalg::RbTreeNode& rhs)
{
return keyComparator()(lhs, static_cast<const NodeType&>(rhs).value());
}
template <class KEY, class COMPARATOR>
template <class LOOKUP_KEY>
inline
bool SetComparator<KEY, COMPARATOR>::operator()(
const bslalg::RbTreeNode& lhs,
const LOOKUP_KEY& rhs)
{
return keyComparator()(static_cast<const NodeType&>(lhs).value(), rhs);
}
template <class KEY, class COMPARATOR>
inline
void SetComparator<KEY, COMPARATOR>::swap(
SetComparator<KEY, COMPARATOR>& other)
{
bslalg::SwapUtil::swap(
static_cast<typename bslalg::FunctorAdapter<COMPARATOR>::Type*>(this),
static_cast<typename bslalg::FunctorAdapter<COMPARATOR>::Type*>(
BSLS_UTIL_ADDRESSOF(other)));
}
// ACCESSORS
template <class KEY, class COMPARATOR>
template <class LOOKUP_KEY>
inline
bool SetComparator<KEY, COMPARATOR>::operator()(
const LOOKUP_KEY& lhs,
const bslalg::RbTreeNode& rhs) const
{
return keyComparator()(lhs, static_cast<const NodeType&>(rhs).value());
}
template <class KEY, class COMPARATOR>
template <class LOOKUP_KEY>
inline
bool SetComparator<KEY, COMPARATOR>::operator()(
const bslalg::RbTreeNode& lhs,
const LOOKUP_KEY& rhs) const
{
return keyComparator()(static_cast<const NodeType&>(lhs).value(), rhs);
}
template <class KEY, class COMPARATOR>
inline
COMPARATOR& SetComparator<KEY, COMPARATOR>::keyComparator()
{
return *this;
}
template <class KEY, class COMPARATOR>
inline
const COMPARATOR& SetComparator<KEY, COMPARATOR>::keyComparator() const
{
return *this;
}
// FREE FUNCTIONS
template <class KEY, class COMPARATOR>
inline
void swap(SetComparator<KEY, COMPARATOR>& a,
SetComparator<KEY, COMPARATOR>& b)
{
a.swap(b);
}
} // close package namespace
} // 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 ----------------------------------