third_party/WebKit/Source/wtf/text/CString.h

   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