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Diffstat (limited to 'security/sandbox/chromium/base/stl_util.h')
-rw-r--r-- | security/sandbox/chromium/base/stl_util.h | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/stl_util.h b/security/sandbox/chromium/base/stl_util.h new file mode 100644 index 000000000..12e226a9d --- /dev/null +++ b/security/sandbox/chromium/base/stl_util.h @@ -0,0 +1,262 @@ +// Copyright (c) 2011 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +// Derived from google3/util/gtl/stl_util.h + +#ifndef BASE_STL_UTIL_H_ +#define BASE_STL_UTIL_H_ + +#include <algorithm> +#include <functional> +#include <iterator> +#include <string> +#include <vector> + +#include "base/logging.h" + +// 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; + } +} + +// Counts the number of instances of val in a container. +template <typename Container, typename T> +typename std::iterator_traits< + typename Container::const_iterator>::difference_type +STLCount(const Container& container, const T& val) { + return std::count(container.begin(), container.end(), val); +} + +// 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; + STLDeleteContainerPairSecondPointers(container->begin(), container->end()); + 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(); +} + +// Test to see if a collection like a vector contains a particular value. +// Returns true if the value is in the collection. +template <typename Collection, typename Value> +bool ContainsValue(const Collection& collection, const Value& value) { + return std::find(collection.begin(), collection.end(), value) != + collection.end(); +} + +namespace base { + +// 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) { + DCHECK(STLIsSorted(a1)); + DCHECK(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) { + DCHECK(STLIsSorted(a1)); + DCHECK(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) { + DCHECK(STLIsSorted(a1)); + DCHECK(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) { + DCHECK(STLIsSorted(a1)); + DCHECK(STLIsSorted(a2)); + return std::includes(a1.begin(), a1.end(), + a2.begin(), a2.end()); +} + +} // namespace base + +#endif // BASE_STL_UTIL_H_ |