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       1             : // Protocol Buffers - Google's data interchange format
       2             : // Copyright 2008 Google Inc.  All rights reserved.
       3             : // https://developers.google.com/protocol-buffers/
       4             : //
       5             : // Redistribution and use in source and binary forms, with or without
       6             : // modification, are permitted provided that the following conditions are
       7             : // met:
       8             : //
       9             : //     * Redistributions of source code must retain the above copyright
      10             : // notice, this list of conditions and the following disclaimer.
      11             : //     * Redistributions in binary form must reproduce the above
      12             : // copyright notice, this list of conditions and the following disclaimer
      13             : // in the documentation and/or other materials provided with the
      14             : // distribution.
      15             : //     * Neither the name of Google Inc. nor the names of its
      16             : // contributors may be used to endorse or promote products derived from
      17             : // this software without specific prior written permission.
      18             : //
      19             : // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      20             : // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      21             : // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      22             : // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      23             : // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      24             : // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      25             : // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      26             : // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      27             : // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      28             : // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      29             : // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      30             : 
      31             : // from google3/util/gtl/stl_util.h
      32             : 
      33             : #ifndef GOOGLE_PROTOBUF_STUBS_STL_UTIL_H__
      34             : #define GOOGLE_PROTOBUF_STUBS_STL_UTIL_H__
      35             : 
      36             : #include <google/protobuf/stubs/common.h>
      37             : 
      38             : namespace google {
      39             : namespace protobuf {
      40             : 
      41             : // STLDeleteContainerPointers()
      42             : //  For a range within a container of pointers, calls delete
      43             : //  (non-array version) on these pointers.
      44             : // NOTE: for these three functions, we could just implement a DeleteObject
      45             : // functor and then call for_each() on the range and functor, but this
      46             : // requires us to pull in all of algorithm.h, which seems expensive.
      47             : // For hash_[multi]set, it is important that this deletes behind the iterator
      48             : // because the hash_set may call the hash function on the iterator when it is
      49             : // advanced, which could result in the hash function trying to deference a
      50             : // stale pointer.
      51             : template <class ForwardIterator>
      52           0 : void STLDeleteContainerPointers(ForwardIterator begin,
      53             :                                 ForwardIterator end) {
      54           0 :   while (begin != end) {
      55           0 :     ForwardIterator temp = begin;
      56           0 :     ++begin;
      57           0 :     delete *temp;
      58             :   }
      59           0 : }
      60             : 
      61             : // Inside Google, this function implements a horrible, disgusting hack in which
      62             : // we reach into the string's private implementation and resize it without
      63             : // initializing the new bytes.  In some cases doing this can significantly
      64             : // improve performance.  However, since it's totally non-portable it has no
      65             : // place in open source code.  Feel free to fill this function in with your
      66             : // own disgusting hack if you want the perf boost.
      67         738 : inline void STLStringResizeUninitialized(string* s, size_t new_size) {
      68         738 :   s->resize(new_size);
      69         738 : }
      70             : 
      71             : // Return a mutable char* pointing to a string's internal buffer,
      72             : // which may not be null-terminated. Writing through this pointer will
      73             : // modify the string.
      74             : //
      75             : // string_as_array(&str)[i] is valid for 0 <= i < str.size() until the
      76             : // next call to a string method that invalidates iterators.
      77             : //
      78             : // As of 2006-04, there is no standard-blessed way of getting a
      79             : // mutable reference to a string's internal buffer. However, issue 530
      80             : // (http://www.open-std.org/JTC1/SC22/WG21/docs/lwg-active.html#530)
      81             : // proposes this as the method. According to Matt Austern, this should
      82             : // already work on all current implementations.
      83         738 : inline char* string_as_array(string* str) {
      84             :   // DO NOT USE const_cast<char*>(str->data())! See the unittest for why.
      85         738 :   return str->empty() ? NULL : &*str->begin();
      86             : }
      87             : 
      88             : // STLDeleteElements() deletes all the elements in an STL container and clears
      89             : // the container.  This function is suitable for use with a vector, set,
      90             : // hash_set, or any other STL container which defines sensible begin(), end(),
      91             : // and clear() methods.
      92             : //
      93             : // If container is NULL, this function is a no-op.
      94             : //
      95             : // As an alternative to calling STLDeleteElements() directly, consider
      96             : // ElementDeleter (defined below), which ensures that your container's elements
      97             : // are deleted when the ElementDeleter goes out of scope.
      98             : template <class T>
      99           0 : void STLDeleteElements(T *container) {
     100           0 :   if (!container) return;
     101           0 :   STLDeleteContainerPointers(container->begin(), container->end());
     102           0 :   container->clear();
     103             : }
     104             : 
     105             : // Given an STL container consisting of (key, value) pairs, STLDeleteValues
     106             : // deletes all the "value" components and clears the container.  Does nothing
     107             : // in the case it's given a NULL pointer.
     108             : 
     109             : template <class T>
     110           0 : void STLDeleteValues(T *v) {
     111           0 :   if (!v) return;
     112           0 :   for (typename T::iterator i = v->begin(); i != v->end(); ++i) {
     113           0 :     delete i->second;
     114             :   }
     115           0 :   v->clear();
     116             : }
     117             : 
     118             : }  // namespace protobuf
     119             : }  // namespace google
     120             : 
     121             : #endif  // GOOGLE_PROTOBUF_STUBS_STL_UTIL_H__