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      1 /*
      2  * Copyright (C) 2008, 2010 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Inc. ("Apple") nor the names of its
     14  *     contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #ifndef StringBuffer_h
     30 #define StringBuffer_h
     31 
     32 #include "wtf/Assertions.h"
     33 #include "wtf/text/StringImpl.h"
     34 #include "wtf/unicode/Unicode.h"
     35 
     36 namespace WTF {
     37 
     38 template <typename CharType>
     39 class StringBuffer {
     40     WTF_MAKE_NONCOPYABLE(StringBuffer);
     41 public:
     42     StringBuffer() { }
     43 
     44     explicit StringBuffer(unsigned length)
     45     {
     46         CharType* characters;
     47         m_data = StringImpl::createUninitialized(length, characters);
     48     }
     49 
     50     ~StringBuffer()
     51     {
     52     }
     53 
     54     void shrink(unsigned newLength)
     55     {
     56         if (m_data->length() == newLength)
     57             return;
     58         m_data->truncateAssumingIsolated(newLength);
     59     }
     60 
     61     void resize(unsigned newLength)
     62     {
     63         if (!m_data) {
     64             CharType* characters;
     65             m_data = StringImpl::createUninitialized(newLength, characters);
     66             return;
     67         }
     68         if (newLength > m_data->length()) {
     69             CharType* characters;
     70             m_data = StringImpl::reallocate(m_data.release(), newLength, characters);
     71             return;
     72         }
     73         shrink(newLength);
     74     }
     75 
     76     unsigned length() const { return m_data ? m_data->length() : 0; }
     77     CharType* characters() { return length() ? const_cast<CharType*>(m_data->getCharacters<CharType>()) : 0; }
     78 
     79     CharType& operator[](unsigned i) { ASSERT_WITH_SECURITY_IMPLICATION(i < length()); return characters()[i]; }
     80 
     81     PassRefPtr<StringImpl> release() { return m_data.release(); }
     82 
     83 private:
     84     RefPtr<StringImpl> m_data;
     85 };
     86 
     87 } // namespace WTF
     88 
     89 using WTF::StringBuffer;
     90 
     91 #endif // StringBuffer_h
     92