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/*
* Copyright 2010 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef URLBuffer_h
#define URLBuffer_h
#if USE(WTFURL)
namespace WTF {
// Base class for the canonicalizer output, this maintains a buffer and
// supports simple resizing and append operations on it.
//
// It is VERY IMPORTANT that no virtual function calls be made on the common
// code path. We only have two virtual function calls, the destructor and a
// resize function that is called when the existing buffer is not big enough.
// The derived class is then in charge of setting up our buffer which we will
// manage.
template<typename CharacterType>
class URLBuffer {
public:
URLBuffer() : m_buffer(0), m_capacity(0), m_length(0) { }
virtual ~URLBuffer() { }
// Implemented to resize the buffer. This function should update the buffer
// pointer to point to the new buffer, and any old data up to |m_length| in
// the buffer must be copied over.
//
// The new size must be larger than m_capacity.
virtual void resize(int) = 0;
inline char at(int offset) const { return m_buffer[offset]; }
inline void set(int offset, CharacterType ch)
{
// FIXME: Add ASSERT(offset < length());
m_buffer[offset] = ch;
}
// Returns the current capacity of the buffer. The length() is the number of
// characters that have been declared to be written, but the capacity() is
// the number that can be written without reallocation. If the caller must
// write many characters at once, it can make sure there is enough capacity,
// write the data, then use setLength() to declare the new length().
int capacity() const { return m_capacity; }
int length() const { return m_length; }
// The output will NOT be 0-terminated. Call length() to get the length.
const CharacterType* data() const { return m_buffer; }
CharacterType* data() { return m_buffer; }
// Shortens the URL to the new length. Used for "backing up" when processing
// relative paths. This can also be used if an external function writes a lot
// of data to the buffer (when using the "Raw" version below) beyond the end,
// to declare the new length.
void setLength(int length)
{
// FIXME: Add ASSERT(length < capacity());
m_length = length;
}
// This is the most performance critical function, since it is called for
// every character.
void append(CharacterType ch)
{
// In VC2005, putting this common case first speeds up execution
// dramatically because this branch is predicted as taken.
if (m_length < m_capacity) {
m_buffer[m_length] = ch;
++m_length;
return;
}
if (!grow(1))
return;
m_buffer[m_length] = ch;
++m_length;
}
void append(const CharacterType* str, int strLength)
{
if (m_length + strLength > m_capacity) {
if (!grow(m_length + strLength - m_capacity))
return;
}
for (int i = 0; i < strLength; i++)
m_buffer[m_length + i] = str[i];
m_length += strLength;
}
protected:
// Returns true if the buffer could be resized, false on OOM.
bool grow(int minimumAdditionalCapacity)
{
static const int minimumCapacity = 16;
int newCapacity = m_capacity ? m_capacity : minimumCapacity;
do {
if (newCapacity >= (1 << 30)) // Prevent overflow below.
return false;
newCapacity *= 2;
} while (newCapacity < m_capacity + minimumAdditionalCapacity);
resize(newCapacity);
return true;
}
CharacterType* m_buffer;
int m_capacity;
int m_length; // Used characters in the buffer.
};
} // namespace WTF
#endif // USE(WTFURL)
#endif // URLBuffer_h
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