//
// VMime library (http://www.vmime.org)
// Copyright (C) 2002 Vincent Richard <vincent@vmime.org>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 3 of
// the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// Linking this library statically or dynamically with other modules is making
// a combined work based on this library.  Thus, the terms and conditions of
// the GNU General Public License cover the whole combination.
//

#include "vmime/utility/seekableInputStreamRegionAdapter.hpp"


namespace vmime {
namespace utility {


seekableInputStreamRegionAdapter::seekableInputStreamRegionAdapter(
	const shared_ptr <seekableInputStream>& stream,
	const size_t begin,
	const size_t length
)
	: m_stream(stream),
	  m_begin(begin),
	  m_length(length),
	  m_position(0) {

}


bool seekableInputStreamRegionAdapter::eof() const {

	return m_position >= m_length;
}


void seekableInputStreamRegionAdapter::reset() {

	m_position = 0;
}


size_t seekableInputStreamRegionAdapter::read(byte_t* const data, const size_t count) {

	m_stream->seek(m_begin + m_position);

	size_t readBytes = 0;

	if (m_position + count >= m_length) {

		const size_t remaining = m_length - m_position;
		readBytes = m_stream->read(data, remaining);

	} else {

		readBytes = m_stream->read(data, count);
	}

	m_position += readBytes;

	return readBytes;
}


size_t seekableInputStreamRegionAdapter::skip(const size_t count) {

	if (m_position + count >= m_length) {

		const size_t remaining = m_length - m_position;
		m_position += remaining;
		return remaining;

	} else {

		m_position += count;
		return count;
	}
}


size_t seekableInputStreamRegionAdapter::getPosition() const {

	return m_position;
}


void seekableInputStreamRegionAdapter::seek(const size_t pos) {

	if (pos > m_length) {
		m_position = m_length;
	} else {
		m_position = pos;
	}
}


} // utility
} // vmime