// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//

// * Redistributions of source code must retain the above copyright notice,

//   this list of conditions and the following disclaimer.

// * Redistributions in binary form must reproduce the above copyright notice,

//   this list of conditions and the following disclaimer in the documentation

//   and/or other materials provided with the distribution.

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//   used to endorse or promote products derived from this software without

//   specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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// Author: keir@google.com (Keir Mierle)

#ifndef CERES_INTERNAL_STL_UTIL_H_

#define CERES_INTERNAL_STL_UTIL_H_

#include <algorithm>

namespace ceres {

// STLDeleteContainerPointers()

//  For a range within a container of pointers, calls delete

//  (non-array version) on these pointers.

// NOTE: for these three functions, we could just implement a DeleteObject

// functor and then call for_each() on the range and functor, but this

// requires us to pull in all of algorithm.h, which seems expensive.

// For hash_[multi]set, it is important that this deletes behind the iterator

// because the hash_set may call the hash function on the iterator when it is

// advanced, which could result in the hash function trying to deference a

// stale pointer.

template <class ForwardIterator>

void STLDeleteContainerPointers(ForwardIterator begin,

                                ForwardIterator end) {

  while (begin != end) {

    ForwardIterator temp = begin;

    ++begin;

    delete *temp;

  }

}

// Variant of STLDeleteContainerPointers which allows the container to

// contain duplicates.

template <class ForwardIterator>

void STLDeleteUniqueContainerPointers(ForwardIterator begin,

                                      ForwardIterator end) {

  sort(begin, end);

  ForwardIterator new_end = unique(begin, end);

  while (begin != new_end) {

    ForwardIterator temp = begin;

    ++begin;

    delete *temp;

  }

}

// STLDeleteElements() deletes all the elements in an STL container and clears

// the container.  This function is suitable for use with a vector, set,

// hash_set, or any other STL container which defines sensible begin(), end(),

// and clear() methods.

//

// If container is NULL, this function is a no-op.

//

// As an alternative to calling STLDeleteElements() directly, consider

// ElementDeleter (defined below), which ensures that your container's elements

// are deleted when the ElementDeleter goes out of scope.

template <class T>

void STLDeleteElements(T *container) {

  if (!container) return;

  STLDeleteContainerPointers(container->begin(), container->end());

  container->clear();

}

}  // namespace ceres

#endif  // CERES_INTERNAL_STL_UTIL_H_