The Tor Browser: ipc/chromium/src/base/stl_util-inl.h@6474c204b198 (annotated)

ipc/chromium/src/base/stl_util-inl.h@6474c204b198 (annotated)

ipc/chromium/src/base/stl_util-inl.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // Copyright (c) 2006-2008 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.
 // STL utility functions.  Usually, these replace built-in, but slow(!),
 // STL functions with more efficient versions.
 #ifndef BASE_STL_UTIL_INL_H_
 #define BASE_STL_UTIL_INL_H_
 #include <string.h>  // for memcpy
 #include <functional>
 #include <set>
 #include <string>
 #include <vector>
 #include <cassert>
 // Clear 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);
   obj->reserve(0);  // this is because sometimes "T tmp" allocates objects with
                     // memory (arena implementation?).  use reserve()
                     // to clear() even if it doesn't always work
 }
 // Reduce memory usage on behalf of object if it is using more than
 // "bytes" bytes of space.  By default, we clear objects over 1MB.
 template <class T> inline void STLClearIfBig(T* obj, size_t limit = 1<<20) {
   if (obj->capacity() >= limit) {
     STLClearObject(obj);
   } else {
     obj->clear();
   }
 }
 // Reserve space for STL object.
 // STL's reserve() will always copy.
 // This function avoid the copy if we already have capacity
 template<class T> void STLReserveIfNeeded(T* obj, int new_size) {
   if (obj->capacity() < new_size)   // increase capacity
     obj->reserve(new_size);
   else if (obj->size() > new_size)  // reduce size
     obj->resize(new_size);
 }
 // 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;
   }
 }
 // STLDeleteContainerPairPointers()
 //  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;
   }
 }
 // STLDeleteContainerPairFirstPointers()
 //  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;
   }
 }
 // STLDeleteContainerPairSecondPointers()
 //  For a range within a container of pairs, calls delete
 //  (non-array version) on the SECOND item in the pairs.
 template <class ForwardIterator>
 void STLDeleteContainerPairSecondPointers(ForwardIterator begin,
                                           ForwardIterator end) {
   while (begin != end) {
     delete begin->second;
     ++begin;
   }
 }
 template<typename T>
 inline void STLAssignToVector(std::vector<T>* vec,
                               const T* ptr,
                               size_t n) {
   vec->resize(n);
   memcpy(&vec->front(), ptr, n*sizeof(T));
 }
 /***** Hack to allow faster assignment to a vector *****/
 // This routine speeds up an assignment of 32 bytes to a vector from
 // about 250 cycles per assignment to about 140 cycles.
 //
 // Usage:
 //      STLAssignToVectorChar(&vec, ptr, size);
 //      STLAssignToString(&str, ptr, size);
 inline void STLAssignToVectorChar(std::vector<char>* vec,
                                   const char* ptr,
                                   size_t n) {
   STLAssignToVector(vec, ptr, n);
 }
 inline void STLAssignToString(std::string* str, const char* ptr, size_t n) {
   str->resize(n);
   memcpy(&*str->begin(), ptr, n);
 }
 // 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 allowed to dump core if v is empty.  This
 // function is the most efficient code that will work, taking into
 // account how our STL is actually implemented.  THIS IS NON-PORTABLE
 // CODE, so call us instead of repeating the nonportable code
 // everywhere.  If our STL implementation changes, we will need to
 // change this as well.
 template<typename T>
 inline T* vector_as_array(std::vector<T>* v) {
 # ifdef NDEBUG
   return &*v->begin();
 # else
   return v->empty() ? NULL : &*v->begin();
 # endif
 }
 template<typename T>
 inline const T* vector_as_array(const std::vector<T>* v) {
 # ifdef NDEBUG
   return &*v->begin();
 # else
   return v->empty() ? NULL : &*v->begin();
 # endif
 }
 // 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())! See the unittest for why.
   return str->empty() ? NULL : &*str->begin();
 }
 // These are methods that test two hash maps/sets for equality.  These exist
 // because the == operator in the STL can return false when the maps/sets
 // contain identical elements.  This is because it compares the internal hash
 // tables which may be different if the order of insertions and deletions
 // differed.
 template <class HashSet>
 inline bool
 HashSetEquality(const HashSet& set_a,
                 const HashSet& set_b) {
   if (set_a.size() != set_b.size()) return false;
   for (typename HashSet::const_iterator i = set_a.begin();
        i != set_a.end();
        ++i) {
     if (set_b.find(*i) == set_b.end())
       return false;
   }
   return true;
 }
 template <class HashMap>
 inline bool
 HashMapEquality(const HashMap& map_a,
                 const HashMap& map_b) {
   if (map_a.size() != map_b.size()) return false;
   for (typename HashMap::const_iterator i = map_a.begin();
        i != map_a.end(); ++i) {
     typename HashMap::const_iterator j = map_b.find(i->first);
     if (j == map_b.end()) return false;
     if (i->second != j->second) return false;
   }
   return true;
 }
 // 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 *v) {
   if (!v) return;
   for (typename T::iterator i = v->begin(); i != v->end(); ++i) {
     delete i->second;
   }
   v->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 STLContainer> class STLElementDeleter {
  public:
   STLElementDeleter(STLContainer *ptr) : container_ptr_(ptr) {}
   ~STLElementDeleter() { STLDeleteElements(container_ptr_); }
  private:
   STLContainer *container_ptr_;
 };
 // Given a pointer to an STL container this class will delete all the value
 // pointers when it goes out of scope.
 template<class STLContainer> class STLValueDeleter {
  public:
   STLValueDeleter(STLContainer *ptr) : container_ptr_(ptr) {}
   ~STLValueDeleter() { STLDeleteValues(container_ptr_); }
  private:
   STLContainer *container_ptr_;
 };
 // Forward declare some callback classes in callback.h for STLBinaryFunction
 template <class R, class T1, class T2>
 class ResultCallback2;
 // STLBinaryFunction is a wrapper for the ResultCallback2 class in callback.h
 // It provides an operator () method instead of a Run method, so it may be
 // passed to STL functions in <algorithm>.
 //
 // The client should create callback with NewPermanentCallback, and should
 // delete callback after it is done using the STLBinaryFunction.
 template <class Result, class Arg1, class Arg2>
 class STLBinaryFunction : public std::binary_function<Arg1, Arg2, Result> {
  public:
   typedef ResultCallback2<Result, Arg1, Arg2> Callback;
   STLBinaryFunction(Callback* callback)
     : callback_(callback) {
     assert(callback_);
   }
   Result operator() (Arg1 arg1, Arg2 arg2) {
     return callback_->Run(arg1, arg2);
   }
  private:
   Callback* callback_;
 };
 // STLBinaryPredicate is a specialized version of STLBinaryFunction, where the
 // return type is bool and both arguments have type Arg.  It can be used
 // wherever STL requires a StrictWeakOrdering, such as in sort() or
 // lower_bound().
 //
 // templated typedefs are not supported, so instead we use inheritance.
 template <class Arg>
 class STLBinaryPredicate : public STLBinaryFunction<bool, Arg, Arg> {
  public:
   typedef typename STLBinaryPredicate<Arg>::Callback Callback;
   STLBinaryPredicate(Callback* callback)
     : STLBinaryFunction<bool, Arg, Arg>(callback) {
   }
 };
 // Functors that compose arbitrary unary and binary functions with a
 // function that "projects" one of the members of a pair.
 // Specifically, if p1 and p2, respectively, are the functions that
 // map a pair to its first and second, respectively, members, the
 // table below summarizes the functions that can be constructed:
 //
 // * UnaryOperate1st<pair>(f) returns the function x -> f(p1(x))
 // * UnaryOperate2nd<pair>(f) returns the function x -> f(p2(x))
 // * BinaryOperate1st<pair>(f) returns the function (x,y) -> f(p1(x),p1(y))
 // * BinaryOperate2nd<pair>(f) returns the function (x,y) -> f(p2(x),p2(y))
 //
 // A typical usage for these functions would be when iterating over
 // the contents of an STL map. For other sample usage, see the unittest.
 template<typename Pair, typename UnaryOp>
 class UnaryOperateOnFirst
     : public std::unary_function<Pair, typename UnaryOp::result_type> {
  public:
   UnaryOperateOnFirst() {
   }
   UnaryOperateOnFirst(const UnaryOp& f) : f_(f) {
   }
   typename UnaryOp::result_type operator()(const Pair& p) const {
     return f_(p.first);
   }
  private:
   UnaryOp f_;
 };
 template<typename Pair, typename UnaryOp>
 UnaryOperateOnFirst<Pair, UnaryOp> UnaryOperate1st(const UnaryOp& f) {
   return UnaryOperateOnFirst<Pair, UnaryOp>(f);
 }
 template<typename Pair, typename UnaryOp>
 class UnaryOperateOnSecond
     : public std::unary_function<Pair, typename UnaryOp::result_type> {
  public:
   UnaryOperateOnSecond() {
   }
   UnaryOperateOnSecond(const UnaryOp& f) : f_(f) {
   }
   typename UnaryOp::result_type operator()(const Pair& p) const {
     return f_(p.second);
   }
  private:
   UnaryOp f_;
 };
 template<typename Pair, typename UnaryOp>
 UnaryOperateOnSecond<Pair, UnaryOp> UnaryOperate2nd(const UnaryOp& f) {
   return UnaryOperateOnSecond<Pair, UnaryOp>(f);
 }
 template<typename Pair, typename BinaryOp>
 class BinaryOperateOnFirst
     : public std::binary_function<Pair, Pair, typename BinaryOp::result_type> {
  public:
   BinaryOperateOnFirst() {
   }
   BinaryOperateOnFirst(const BinaryOp& f) : f_(f) {
   }
   typename BinaryOp::result_type operator()(const Pair& p1,
                                             const Pair& p2) const {
     return f_(p1.first, p2.first);
   }
  private:
   BinaryOp f_;
 };
 template<typename Pair, typename BinaryOp>
 BinaryOperateOnFirst<Pair, BinaryOp> BinaryOperate1st(const BinaryOp& f) {
   return BinaryOperateOnFirst<Pair, BinaryOp>(f);
 }
 template<typename Pair, typename BinaryOp>
 class BinaryOperateOnSecond
     : public std::binary_function<Pair, Pair, typename BinaryOp::result_type> {
  public:
   BinaryOperateOnSecond() {
   }
   BinaryOperateOnSecond(const BinaryOp& f) : f_(f) {
   }
   typename BinaryOp::result_type operator()(const Pair& p1,
                                             const Pair& p2) const {
     return f_(p1.second, p2.second);
   }
  private:
   BinaryOp f_;
 };
 template<typename Pair, typename BinaryOp>
 BinaryOperateOnSecond<Pair, BinaryOp> BinaryOperate2nd(const BinaryOp& f) {
   return BinaryOperateOnSecond<Pair, BinaryOp>(f);
 }
 // Translates a set into a vector.
 template<typename T>
 std::vector<T> SetToVector(const std::set<T>& values) {
   std::vector<T> result;
   result.reserve(values.size());
   result.insert(result.begin(), values.begin(), values.end());
   return result;
 }
 #endif  // BASE_STL_UTIL_INL_H_

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ipc/chromium/src/base/stl_util-inl.h@6474c204b198 (annotated)

ipc/chromium/src/base/stl_util-inl.h