wtf/text/StringBuilder.h

   1 /*
   2  * Copyright (C) 2009, 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  * 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 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 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 StringBuilder_h
  27 #define StringBuilder_h
  28
  29 #include <wtf/Vector.h>
  30 #include <wtf/text/WTFString.h>
  31
  32 namespace WTF {
  33
  34 class StringBuilder {
  35 public:
  36     StringBuilder()
  37         : m_length(0)
  38     {
  39     }
  40
  41     void append(const UChar*, unsigned);
  42     void append(const char*, unsigned);
  43
  44     void append(const String& string)
  45     {
  46         // If we're appending to an empty string, and there is not buffer
  47         // (in case reserveCapacity has been called) then just retain the
  48         // string.
  49         if (!m_length && !m_buffer) {
  50             m_string = string;
  51             m_length = string.length();
  52             return;
  53         }
  54         append(string.characters(), string.length());
  55     }
  56
  57     void append(const char* characters)
  58     {
  59         if (characters)
  60             append(characters, strlen(characters));
  61     }
  62
  63     void append(UChar c)
  64     {
  65         if (m_buffer && m_length < m_buffer->length() && m_string.isNull())
  66             m_bufferCharacters[m_length++] = c;
  67         else
  68             append(&c, 1);
  69     }
  70
  71     void append(char c)
  72     {
  73         if (m_buffer && m_length < m_buffer->length() && m_string.isNull())
  74             m_bufferCharacters[m_length++] = (unsigned char)c;
  75         else
  76             append(&c, 1);
  77     }
  78
  79     String toString()
  80     {
  81         if (m_string.isNull()) {
  82             shrinkToFit();
  83             reifyString();
  84         }
  85         return m_string;
  86     }
  87
  88     String toStringPreserveCapacity()
  89     {
  90         if (m_string.isNull())
  91             reifyString();
  92         return m_string;
  93     }
  94
  95     unsigned length() const
  96     {
  97         return m_length;
  98     }
  99
 100     bool isEmpty() const { return !length(); }
 101
 102     void reserveCapacity(unsigned newCapacity);
 103
 104     void resize(unsigned newSize);
 105
 106     void shrinkToFit();
 107
 108     UChar operator[](unsigned i) const
 109     {
 110         ASSERT(i < m_length);
 111         if (!m_string.isNull())
 112             return m_string[i];
 113         ASSERT(m_buffer);
 114         return m_buffer->characters()[i];
 115     }
 116
 117     void clear()
 118     {
 119         m_length = 0;
 120         m_string = String();
 121         m_buffer = 0;
 122     }
 123
 124 private:
 125     void allocateBuffer(const UChar* currentCharacters, unsigned requiredLength);
 126     UChar* appendUninitialized(unsigned length);
 127     void reifyString();
 128
 129     unsigned m_length;
 130     String m_string;
 131     RefPtr<StringImpl> m_buffer;
 132     UChar* m_bufferCharacters;
 133 };
 134
 135 } // namespace WTF
 136
 137 using WTF::StringBuilder;
 138
 139 #endif // StringBuilder_h