third_party/WebKit/Source/wtf/TerminatedArrayBuilder.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4 #ifndef TerminatedArrayBuilder_h
   5 #define TerminatedArrayBuilder_h
   6
   7 #include "wtf/OwnPtr.h"
   8
   9 namespace WTF {
  10
  11 template<typename T, template <typename> class ArrayType = TerminatedArray>
  12 class TerminatedArrayBuilder {
  13     DISALLOW_ALLOCATION();
  14     WTF_MAKE_NONCOPYABLE(TerminatedArrayBuilder);
  15 public:
  16     explicit TerminatedArrayBuilder(typename ArrayType<T>::Allocator::PassPtr array)
  17         : m_array(array)
  18         , m_count(0)
  19         , m_capacity(0)
  20     {
  21         if (!m_array)
  22             return;
  23         m_capacity = m_count = m_array->size();
  24     }
  25
  26     void grow(size_t count)
  27     {
  28         ASSERT(count);
  29         if (!m_array) {
  30             ASSERT(!m_count);
  31             ASSERT(!m_capacity);
  32             m_capacity = count;
  33             m_array = ArrayType<T>::Allocator::create(m_capacity);
  34             return;
  35         }
  36         m_capacity += count;
  37         m_array = ArrayType<T>::Allocator::resize(m_array.release(), m_capacity);
  38         m_array->at(m_count - 1).setLastInArray(false);
  39     }
  40
  41     void append(const T& item)
  42     {
  43         RELEASE_ASSERT(m_count < m_capacity);
  44         ASSERT(!item.isLastInArray());
  45         m_array->at(m_count++) = item;
  46     }
  47
  48     typename ArrayType<T>::Allocator::PassPtr release()
  49     {
  50         RELEASE_ASSERT(m_count == m_capacity);
  51         if (m_array)
  52             m_array->at(m_count - 1).setLastInArray(true);
  53         assertValid();
  54         return m_array.release();
  55     }
  56
  57 private:
  58 #if ENABLE(ASSERT)
  59     void assertValid()
  60     {
  61         for (size_t i = 0; i < m_count; ++i) {
  62             bool isLastInArray = (i + 1 == m_count);
  63             ASSERT(m_array->at(i).isLastInArray() == isLastInArray);
  64         }
  65     }
  66 #else
  67     void assertValid() { }
  68 #endif
  69
  70     typename ArrayType<T>::Allocator::Ptr m_array;
  71     size_t m_count;
  72     size_t m_capacity;
  73 };
  74
  75 } // namespace WTF
  76
  77 using WTF::TerminatedArrayBuilder;
  78
  79 #endif // TerminatedArrayBuilder_h