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      1 /*
      2  * Copyright (C) 2003, 2006, 2008, 2009, 2010, 2012 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  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef CString_h
     27 #define CString_h
     28 
     29 #include "wtf/RefCounted.h"
     30 #include "wtf/RefPtr.h"
     31 #include "wtf/WTFExport.h"
     32 
     33 namespace WTF {
     34 
     35 // CStringBuffer is the ref-counted storage class for the characters in a CString.
     36 // The data is implicitly allocated 1 character longer than length(), as it is zero-terminated.
     37 class WTF_EXPORT CStringBuffer : public RefCounted<CStringBuffer> {
     38 public:
     39     const char* data() { return mutableData(); }
     40     size_t length() const { return m_length; }
     41 
     42 private:
     43     friend class CString;
     44     friend class RefCounted<CStringBuffer>;
     45     // CStringBuffers are allocated out of the WTF buffer partition.
     46     void* operator new(size_t, void* ptr) { return ptr; };
     47     void operator delete(void*);
     48 
     49     static PassRefPtr<CStringBuffer> createUninitialized(size_t length);
     50 
     51     CStringBuffer(size_t length) : m_length(length) { }
     52     char* mutableData() { return reinterpret_cast<char*>(this + 1); }
     53 
     54     const unsigned m_length;
     55 };
     56 
     57 // A container for a null-terminated char array supporting copy-on-write
     58 // assignment.  The contained char array may be null.
     59 class WTF_EXPORT CString {
     60 public:
     61     CString() { }
     62     CString(const char*);
     63     CString(const char*, size_t length);
     64     CString(CStringBuffer* buffer) : m_buffer(buffer) { }
     65     static CString newUninitialized(size_t length, char*& characterBuffer);
     66 
     67     const char* data() const
     68     {
     69         return m_buffer ? m_buffer->data() : 0;
     70     }
     71     char* mutableData();
     72     size_t length() const
     73     {
     74         return m_buffer ? m_buffer->length() : 0;
     75     }
     76 
     77     bool isNull() const { return !m_buffer; }
     78     bool isSafeToSendToAnotherThread() const;
     79 
     80     CStringBuffer* buffer() const { return m_buffer.get(); }
     81 
     82 private:
     83     void copyBufferIfNeeded();
     84     void init(const char*, size_t length);
     85     RefPtr<CStringBuffer> m_buffer;
     86 };
     87 
     88 WTF_EXPORT bool operator==(const CString& a, const CString& b);
     89 inline bool operator!=(const CString& a, const CString& b) { return !(a == b); }
     90 WTF_EXPORT bool operator==(const CString& a, const char* b);
     91 inline bool operator!=(const CString& a, const char* b) { return !(a == b); }
     92 
     93 } // namespace WTF
     94 
     95 using WTF::CString;
     96 
     97 #endif // CString_h
     98