system_wrappers: rename interface -> include

webrtc/system_wrappers/interface/stl_util.h

-/*
- *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-// Borrowed from Chromium's src/base/stl_util.h.
-
-#ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_STL_UTIL_H_
-#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_STL_UTIL_H_
-
-#include <assert.h>
-#include <algorithm>
-#include <functional>
-#include <iterator>
-#include <string>
-#include <vector>
-
-namespace webrtc {
-
-// Clears internal memory of an STL object.
-// STL clear()/reserve(0) does not always free internal memory allocated
-// This function uses swap/destructor to ensure the internal memory is freed.
-template<class T>
-void STLClearObject(T* obj) {
-  T tmp;
-  tmp.swap(*obj);
-  // Sometimes "T tmp" allocates objects with memory (arena implementation?).
-  // Hence using additional reserve(0) even if it doesn't always work.
-  obj->reserve(0);
-}
-
-// 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;
-  }
-}
-
-// For a range within a container of pairs, calls delete (non-array version) on
-// BOTH items in the pairs.
-// NOTE: Like STLDeleteContainerPointers, it is important that this deletes
-// behind the iterator because if both the key and value are deleted, the
-// container may call the hash function on the iterator when it is advanced,
-// which could result in the hash function trying to dereference a stale
-// pointer.
-template <class ForwardIterator>
-void STLDeleteContainerPairPointers(ForwardIterator begin,
-                                    ForwardIterator end) {
-  while (begin != end) {
-    ForwardIterator temp = begin;
-    ++begin;
-    delete temp->first;
-    delete temp->second;
-  }
-}
-
-// For a range within a container of pairs, calls delete (non-array version) on
-// the FIRST item in the pairs.
-// NOTE: Like STLDeleteContainerPointers, deleting behind the iterator.
-template <class ForwardIterator>
-void STLDeleteContainerPairFirstPointers(ForwardIterator begin,
-                                         ForwardIterator end) {
-  while (begin != end) {
-    ForwardIterator temp = begin;
-    ++begin;
-    delete temp->first;
-  }
-}
-
-// For a range within a container of pairs, calls delete.
-// NOTE: Like STLDeleteContainerPointers, deleting behind the iterator.
-// Deleting the value does not always invalidate the iterator, but it may
-// do so if the key is a pointer into the value object.
-template <class ForwardIterator>
-void STLDeleteContainerPairSecondPointers(ForwardIterator begin,
-                                          ForwardIterator end) {
-  while (begin != end) {
-    ForwardIterator temp = begin;
-    ++begin;
-    delete temp->second;
-  }
-}
-
-// To treat a possibly-empty vector as an array, use these functions.
-// If you know the array will never be empty, you can use &*v.begin()
-// directly, but that is undefined behaviour if |v| is empty.
-template<typename T>
-inline T* vector_as_array(std::vector<T>* v) {
-  return v->empty() ? NULL : &*v->begin();
-}
-
-template<typename T>
-inline const T* vector_as_array(const std::vector<T>* v) {
-  return v->empty() ? NULL : &*v->begin();
-}
-
-// Return a mutable char* pointing to a string's internal buffer,
-// which may not be null-terminated. Writing through this pointer will
-// modify the string.
-//
-// string_as_array(&str)[i] is valid for 0 <= i < str.size() until the
-// next call to a string method that invalidates iterators.
-//
-// As of 2006-04, there is no standard-blessed way of getting a
-// mutable reference to a string's internal buffer. However, issue 530
-// (http://www.open-std.org/JTC1/SC22/WG21/docs/lwg-active.html#530)
-// proposes this as the method. According to Matt Austern, this should
-// already work on all current implementations.
-inline char* string_as_array(std::string* str) {
-  // DO NOT USE const_cast<char*>(str->data())
-  return str->empty() ? NULL : &*str->begin();
-}
-
-// The following functions are useful for cleaning up STL containers whose
-// elements point to allocated memory.
-
-// 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
-// STLElementDeleter (defined below), which ensures that your container's
-// elements are deleted when the STLElementDeleter goes out of scope.
-template <class T>
-void STLDeleteElements(T* container) {
-  if (!container)
-    return;
-  STLDeleteContainerPointers(container->begin(), container->end());
-  container->clear();
-}
-
-// Given an STL container consisting of (key, value) pairs, STLDeleteValues
-// deletes all the "value" components and clears the container.  Does nothing
-// in the case it's given a NULL pointer.
-template <class T>
-void STLDeleteValues(T* container) {
-  if (!container)
-    return;
-  for (typename T::iterator i(container->begin()); i != container->end(); ++i)
-    delete i->second;
-  container->clear();
-}
-
-
-// The following classes provide a convenient way to delete all elements or
-// values from STL containers when they goes out of scope.  This greatly
-// simplifies code that creates temporary objects and has multiple return
-// statements.  Example:
-//
-// vector<MyProto *> tmp_proto;
-// STLElementDeleter<vector<MyProto *> > d(&tmp_proto);
-// if (...) return false;
-// ...
-// return success;
-
-// Given a pointer to an STL container this class will delete all the element
-// pointers when it goes out of scope.
-template<class T>
-class STLElementDeleter {
- public:
-  STLElementDeleter<T>(T* container) : container_(container) {}
-  ~STLElementDeleter<T>() { STLDeleteElements(container_); }
-
- private:
-  T* container_;
-};
-
-// Given a pointer to an STL container this class will delete all the value
-// pointers when it goes out of scope.
-template<class T>
-class STLValueDeleter {
- public:
-  STLValueDeleter<T>(T* container) : container_(container) {}
-  ~STLValueDeleter<T>() { STLDeleteValues(container_); }
-
- private:
-  T* container_;
-};
-
-// Test to see if a set, map, hash_set or hash_map contains a particular key.
-// Returns true if the key is in the collection.
-template <typename Collection, typename Key>
-bool ContainsKey(const Collection& collection, const Key& key) {
-  return collection.find(key) != collection.end();
-}
-
-// Returns true if the container is sorted.
-template <typename Container>
-bool STLIsSorted(const Container& cont) {
-  // Note: Use reverse iterator on container to ensure we only require
-  // value_type to implement operator<.
-  return std::adjacent_find(cont.rbegin(), cont.rend(),
-                            std::less<typename Container::value_type>())
-      == cont.rend();
-}
-
-// Returns a new ResultType containing the difference of two sorted containers.
-template <typename ResultType, typename Arg1, typename Arg2>
-ResultType STLSetDifference(const Arg1& a1, const Arg2& a2) {
-  assert(STLIsSorted(a1));
-  assert(STLIsSorted(a2));
-  ResultType difference;
-  std::set_difference(a1.begin(), a1.end(),
-                      a2.begin(), a2.end(),
-                      std::inserter(difference, difference.end()));
-  return difference;
-}
-
-// Returns a new ResultType containing the union of two sorted containers.
-template <typename ResultType, typename Arg1, typename Arg2>
-ResultType STLSetUnion(const Arg1& a1, const Arg2& a2) {
-  assert(STLIsSorted(a1));
-  assert(STLIsSorted(a2));
-  ResultType result;
-  std::set_union(a1.begin(), a1.end(),
-                 a2.begin(), a2.end(),
-                 std::inserter(result, result.end()));
-  return result;
-}
-
-// Returns a new ResultType containing the intersection of two sorted
-// containers.
-template <typename ResultType, typename Arg1, typename Arg2>
-ResultType STLSetIntersection(const Arg1& a1, const Arg2& a2) {
-  assert(STLIsSorted(a1));
-  assert(STLIsSorted(a2));
-  ResultType result;
-  std::set_intersection(a1.begin(), a1.end(),
-                        a2.begin(), a2.end(),
-                        std::inserter(result, result.end()));
-  return result;
-}
-
-// Returns true if the sorted container |a1| contains all elements of the sorted
-// container |a2|.
-template <typename Arg1, typename Arg2>
-bool STLIncludes(const Arg1& a1, const Arg2& a2) {
-  assert(STLIsSorted(a1));
-  assert(STLIsSorted(a2));
-  return std::includes(a1.begin(), a1.end(),
-                       a2.begin(), a2.end());
-}
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_STL_UTIL_H_