1 // Ceres Solver - A fast non-linear least squares minimizer
2 // Copyright 2010, 2011, 2012 Google Inc. All rights reserved.
3 // http://code.google.com/p/ceres-solver/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are met:
7 //
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9 //   this list of conditions and the following disclaimer.
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13 // * Neither the name of Google Inc. nor the names of its contributors may be
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15 //   specific prior written permission.
16 //
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29 // Author: keir@google.com (Keir Mierle)
30 
31 #ifndef CERES_INTERNAL_STL_UTIL_H_
32 #define CERES_INTERNAL_STL_UTIL_H_
33 
34 #include <algorithm>
35 
36 namespace ceres {
37 
38 // STLDeleteContainerPointers()
39 //  For a range within a container of pointers, calls delete
40 //  (non-array version) on these pointers.
41 // NOTE: for these three functions, we could just implement a DeleteObject
42 // functor and then call for_each() on the range and functor, but this
43 // requires us to pull in all of algorithm.h, which seems expensive.
44 // For hash_[multi]set, it is important that this deletes behind the iterator
45 // because the hash_set may call the hash function on the iterator when it is
46 // advanced, which could result in the hash function trying to deference a
47 // stale pointer.
48 template <class ForwardIterator>
STLDeleteContainerPointers(ForwardIterator begin,ForwardIterator end)49 void STLDeleteContainerPointers(ForwardIterator begin,
50                                 ForwardIterator end) {
51   while (begin != end) {
52     ForwardIterator temp = begin;
53     ++begin;
54     delete *temp;
55   }
56 }
57 
58 // Variant of STLDeleteContainerPointers which allows the container to
59 // contain duplicates.
60 template <class ForwardIterator>
STLDeleteUniqueContainerPointers(ForwardIterator begin,ForwardIterator end)61 void STLDeleteUniqueContainerPointers(ForwardIterator begin,
62                                       ForwardIterator end) {
63   sort(begin, end);
64   ForwardIterator new_end = unique(begin, end);
65   while (begin != new_end) {
66     ForwardIterator temp = begin;
67     ++begin;
68     delete *temp;
69   }
70 }
71 
72 // STLDeleteElements() deletes all the elements in an STL container and clears
73 // the container.  This function is suitable for use with a vector, set,
74 // hash_set, or any other STL container which defines sensible begin(), end(),
75 // and clear() methods.
76 //
77 // If container is NULL, this function is a no-op.
78 //
79 // As an alternative to calling STLDeleteElements() directly, consider
80 // ElementDeleter (defined below), which ensures that your container's elements
81 // are deleted when the ElementDeleter goes out of scope.
82 template <class T>
STLDeleteElements(T * container)83 void STLDeleteElements(T *container) {
84   if (!container) return;
85   STLDeleteContainerPointers(container->begin(), container->end());
86   container->clear();
87 }
88 
89 }  // namespace ceres
90 
91 #endif  // CERES_INTERNAL_STL_UTIL_H_
92