mirror of
https://github.com/FirebirdSQL/firebird.git
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111 lines
3.7 KiB
C++
111 lines
3.7 KiB
C++
/*
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* The contents of this file are subject to the Initial
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* Developer's Public License Version 1.0 (the "License");
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* you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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* http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
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*
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* Software distributed under the License is distributed AS IS,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied.
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* See the License for the specific language governing rights
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* and limitations under the License.
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*
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* The Original Code was created by Claudio Valderrama on 25-Feb-2007
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* for the Firebird Open Source RDBMS project.
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*
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* Copyright (c) 2007 Claudio Valderrama
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* and all contributors signed below.
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*
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* All Rights Reserved.
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* Contributor(s): ______________________________________.
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*
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*/
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#include "firebird.h"
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#include "Extender.h"
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#include "../common/classes/alloc.h"
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// Dynamic allocation. This is a destructive operation if the requested size
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// is bigger than the existing one. Otherwise, no reallocation happens.
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// The insertion point is always reset. This means getUsed() returns zero after
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// this call. The first byte is initialized to zero to aid in debugging.
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// If size zero is passed, no allocation happens but the insertion point is reset.
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void Extender::alloc(size_t n)
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{
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if (m_size < n)
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{
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delete[] m_buf;
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m_buf = new char[m_size = n];
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m_buf[0] = 0;
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}
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m_pos = m_buf;
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}
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// Allocation plus initialization. Same as alloc(), but initializes the internal
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// buffer with the desired byte.
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// This means the first byte intialization to zero in alloc() is wiped out.
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void Extender::allocFill(size_t n, char c)
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{
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alloc(n);
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memset(m_buf, c, n);
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}
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// Append to the string. Note second parameter is the size, not the length.
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// This means that a null terminator is not added unless the input contains it.
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// If there's already a null terminator, it's not discarded before appending!
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// If there's space used, a newline is optionally used as separator between
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// the existing content and the new input.
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// The internal buffer is not grown; the input will be truncated.
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// The amount of written bytes (the ones that fit) is returned.
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size_t Extender::append(const char* s, size_t s_size, bool newline)
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{
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if (m_pos >= m_buf + m_size) // Full buffer?
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return 0;
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const size_t extra = m_buf < m_pos && newline ? 1 : 0;
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if (m_pos + s_size + extra > m_buf + m_size) // Adjust the argument, truncating it.
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s_size = m_buf + m_size - m_pos - extra;
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// Do not append newline if there's nothing before or the caller doesn't want it.
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if (extra)
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*m_pos++ = '\n';
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memcpy(m_pos, s, s_size);
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m_pos += s_size;
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return s_size + extra;
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}
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// Unlike alloc() and allocFill(), this is not a destructive operation.
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// If the requested size is not bigger than the existing one, nothing happens and
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// the insertion point remains in its current position.
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// Otherwise, reallocation happens and the old contents are copied into the
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// new buffer. Notice only getUsed() bytes are copied. This means a fill pattern
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// will not be preserved. The insertion point is updated after the copy to point
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// to the same position in the string where it was before growing the buffer.
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// The position at the insertion point is initialized to zero to aid in debugging.
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void Extender::grow(size_t n)
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{
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if (m_pos == m_buf)
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{
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// We don't have data to preserve, go faster.
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alloc(n);
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return;
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}
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if (m_size < n)
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{
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const size_t old_pos = getUsed();
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char* const old_buf = m_buf;
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m_buf = new char[m_size = n];
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memcpy(m_buf, old_buf, old_pos); // Copy only the used bytes.
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m_pos = m_buf + old_pos; // Reposition the current insertion point.
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m_pos[0] = 0; // Same as alloc().
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delete[] old_buf;
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}
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}
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