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      1 /*
      2  * Copyright (C) 2003, 2006, 2008, 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 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 
     27 #include "config.h"
     28 #include "CString.h"
     29 
     30 using namespace std;
     31 
     32 namespace WTF {
     33 
     34 CString::CString(const char* str)
     35 {
     36     if (!str)
     37         return;
     38 
     39     init(str, strlen(str));
     40 }
     41 
     42 CString::CString(const char* str, size_t length)
     43 {
     44     init(str, length);
     45 }
     46 
     47 void CString::init(const char* str, size_t length)
     48 {
     49     if (!str)
     50         return;
     51 
     52     // We need to be sure we can add 1 to length without overflowing.
     53     // Since the passed-in length is the length of an actual existing
     54     // string, and we know the string doesn't occupy the entire address
     55     // space, we can assert here and there's no need for a runtime check.
     56     ASSERT(length < numeric_limits<size_t>::max());
     57 
     58     m_buffer = CStringBuffer::create(length + 1);
     59     memcpy(m_buffer->mutableData(), str, length);
     60     m_buffer->mutableData()[length] = '\0';
     61 }
     62 
     63 char* CString::mutableData()
     64 {
     65     copyBufferIfNeeded();
     66     if (!m_buffer)
     67         return 0;
     68     return m_buffer->mutableData();
     69 }
     70 
     71 CString CString::newUninitialized(size_t length, char*& characterBuffer)
     72 {
     73     if (length >= numeric_limits<size_t>::max())
     74         CRASH();
     75 
     76     CString result;
     77     result.m_buffer = CStringBuffer::create(length + 1);
     78     char* bytes = result.m_buffer->mutableData();
     79     bytes[length] = '\0';
     80     characterBuffer = bytes;
     81     return result;
     82 }
     83 
     84 void CString::copyBufferIfNeeded()
     85 {
     86     if (!m_buffer || m_buffer->hasOneRef())
     87         return;
     88 
     89     RefPtr<CStringBuffer> buffer = m_buffer.release();
     90     size_t length = buffer->length();
     91     m_buffer = CStringBuffer::create(length);
     92     memcpy(m_buffer->mutableData(), buffer->data(), length);
     93 }
     94 
     95 bool operator==(const CString& a, const CString& b)
     96 {
     97     if (a.isNull() != b.isNull())
     98         return false;
     99     if (a.length() != b.length())
    100         return false;
    101     return !strncmp(a.data(), b.data(), min(a.length(), b.length()));
    102 }
    103 
    104 } // namespace WTF
    105