wtf/text/CString.cpp

   1 /*
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   5  * modification, are permitted provided that the following conditions
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   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
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  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