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firebird-mirror/src/isql/Extender.h

92 lines
2.6 KiB
C++

/*
* The contents of this file are subject to the Initial
* Developer's Public License Version 1.0 (the "License");
* you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
* http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
*
* Software distributed under the License is distributed AS IS,
* WITHOUT WARRANTY OF ANY KIND, either express or implied.
* See the License for the specific language governing rights
* and limitations under the License.
*
* The Original Code was created by Claudio Valderrama on 25-Feb-2007
* for the Firebird Open Source RDBMS project.
*
* Copyright (c) 2007 Claudio Valderrama
* and all contributors signed below.
*
* All Rights Reserved.
* Contributor(s): ______________________________________.
*
*/
#ifndef FB_EXTENDER_H
#define FB_EXTENDER_H
// Helper class for the bulk insertion tricks.
// It does automatic resource management
// and appends starting with newline when there's anything already in the buffer.
// Calling alloc() again with a bigger buffer size simply forgets the old data.
// Calling alloc() always resets the usage counter to zero, hence the first
// call to append() after alloc() always work as a simple copy.
// Using the object is only valid after the first append() call.
// This class can be used with binary data that includes the null terminator,
// although it was designed for text (see the newline inserted by append()).
// It only puts the null terminator on allocation; no warranties getBuffer()
// will return a null terminated string unless append() received it.
#include <memory.h>
class Extender
{
public:
Extender();
~Extender();
void alloc(size_t n);
void allocFill(size_t n, char c);
size_t append(const char* s, size_t s_size, bool newline = true);
char* getBuffer();
const char* getBuffer() const;
size_t getUsed() const;
protected:
void grow(size_t n);
private:
char* m_buf;
size_t m_size;
char* m_pos;
};
inline Extender::Extender()
: m_buf(0), m_size(0), m_pos(0)
{
}
inline Extender::~Extender()
{
delete[] m_buf;
}
inline char* Extender::getBuffer()
{
return m_buf;
}
// Probably won't be used as I can't imagine a const Extender object except
// when passed to another function as const param with content already stored.
inline const char* Extender::getBuffer() const
{
return m_buf;
}
// It uses the current insertion point to calculate an offset from the base address.
// This is in turn the number of effective bytes in use from the whole allocation.
inline size_t Extender::getUsed() const
{
return m_pos - m_buf;
}
#endif // FB_EXTENDER_H