DVTOOLFileReader.cpp

/*
 *   Copyright (C) 2009,2013,2014 by Jonathan Naylor G4KLX
 *   Copyright (c) 2017 by Thomas A. Early N7TAE
 *
 *   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 2 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <cstring>
#include <arpa/inet.h>

#include "DVTOOLFileReader.h"
#include "DStarDefines.h"

static const char         DVTOOL_SIGNATURE[] = "DVTOOL";
static const unsigned int DVTOOL_SIGNATURE_LENGTH = 6U;

static const char         DSVT_SIGNATURE[] = "DSVT";
static const unsigned int DSVT_SIGNATURE_LENGTH = 4U;

static const unsigned int FIXED_DATA_LENGTH = 9U;

static const unsigned char HEADER_FLAG   = 0x10;
static const unsigned char DATA_FLAG     = 0x20;

static const unsigned char HEADER_MASK   = 0x80;
static const unsigned char TRAILER_MASK  = 0x40;

const unsigned int BUFFER_LENGTH = 255U;


CDVTOOLFileReader::CDVTOOLFileReader() :
m_fileName(),
m_file(NULL),
m_records(0U),
m_type(DVTFR_NONE),
m_buffer(NULL),
m_length(0U),
m_seqNo(0U)
{
	m_buffer = new unsigned char[BUFFER_LENGTH];
}

CDVTOOLFileReader::~CDVTOOLFileReader()
{
	delete[] m_buffer;
}

std::string CDVTOOLFileReader::getFileName() const
{
	return m_fileName;
}

unsigned int CDVTOOLFileReader::getRecords() const
{
	return m_records;
}

bool CDVTOOLFileReader::open(const std::string& fileName)
{
	m_fileName = fileName;

	m_file = fopen(fileName.c_str(), "rb");
	if (NULL == m_file)
		return false;

	unsigned char buffer[DVTOOL_SIGNATURE_LENGTH];
	size_t n = fread(buffer, 1, DVTOOL_SIGNATURE_LENGTH, m_file);
	if (n != DVTOOL_SIGNATURE_LENGTH) {
		fclose(m_file);
		return false;
	}

	if (::memcmp(buffer, DVTOOL_SIGNATURE, DVTOOL_SIGNATURE_LENGTH) != 0) {
		fclose(m_file);
		return false;
	}

	uint32_t uint32;
	n = fread(&uint32, sizeof(uint32_t), 1, m_file);
	if (n != 1) {
		fclose(m_file);
		return false;
	}

	m_records = ntohl(uint32);
	m_seqNo   = 0U;

	return true;
}

DVTFR_TYPE CDVTOOLFileReader::read()
{
	uint16_t uint16;
	size_t n = fread(&uint16, sizeof(uint16_t), 1, m_file);
	if (n != 1)
		return DVTFR_NONE;

	m_length = htons(uint16) - 15U;

	unsigned char bytes[FIXED_DATA_LENGTH];
	n = fread(bytes, 1, DSVT_SIGNATURE_LENGTH, m_file);
	if (n != DSVT_SIGNATURE_LENGTH)
		return DVTFR_NONE;

	if (::memcmp(bytes, DSVT_SIGNATURE, DSVT_SIGNATURE_LENGTH) != 0)
		return DVTFR_NONE;

	char flag;
	n = fread(&flag, 1, 1, m_file);
	if (n != 1)
		return DVTFR_NONE;

	m_type = (flag == HEADER_FLAG) ? DVTFR_HEADER : DVTFR_DATA;

	n = fread(bytes, 1, FIXED_DATA_LENGTH, m_file);
	if (n != FIXED_DATA_LENGTH)
		return DVTFR_NONE;

	n = fread(&flag, 1, 1, m_file);
	if (n != 1)
		return DVTFR_NONE;

	if (m_type == DVTFR_DATA)
		m_seqNo = flag;

	n = fread(m_buffer, 1, m_length, m_file);
	if (n != m_length)
		return DVTFR_NONE;

	return m_type;
}

CHeaderData* CDVTOOLFileReader::readHeader()
{
	if (m_type != DVTFR_HEADER)
		return NULL;

	CHeaderData* header = new CHeaderData;

	if (m_buffer[39U] == 0xFFU && m_buffer[40U] == 0xFFU) {
		header->setDVTOOLData(m_buffer, RADIO_HEADER_LENGTH_BYTES, false);
		return header;
	}

	// Header checksum testing is enabled
	bool valid = header->setDVTOOLData(m_buffer, RADIO_HEADER_LENGTH_BYTES, true);
	if (!valid) {
		delete header;
		return NULL;
	}

	return header;
}

CAMBEData* CDVTOOLFileReader::readData()
{
	if (m_type != DVTFR_DATA)
		return NULL;

	CAMBEData* data = new CAMBEData;

	data->setData(m_buffer, m_length);
	data->setSeq(m_seqNo);

	return data;
}

void CDVTOOLFileReader::close()
{
	fclose(m_file);
}