xdfwriter.cpp

#include "xdfwriter.h"
#include <iostream>

void write_timestamp(std::ostream &out, double ts) {
	// [TimeStampBytes] (0 for no time stamp)
	if (ts == 0)
		out.put(0);
	else {
		// [TimeStampBytes]
		out.put(8);
		// [TimeStamp]
		write_little_endian(out, ts);
	}
}

XDFWriter::XDFWriter(const std::string &filename)
#ifndef XDFZ_SUPPORT
	: file_(filename, std::ios::binary | std::ios::trunc)
#endif
{
	// open file stream
#ifdef XDFZ_SUPPORT
	if (boost::iends_with(filename, ".xdfz")) file_.push(boost::iostreams::zlib_compressor());
	file_.push(
		boost::iostreams::file_descriptor_sink(filename, std::ios::binary | std::ios::trunc));
#endif
	// [MagicCode]
	file_ << "XDF:";
	// [FileHeader] chunk
	_write_chunk(
		chunk_tag_t::fileheader, "<?xml version=\"1.0\"?><info><version>1.0</version></info>");
}

void XDFWriter::_write_chunk(
	chunk_tag_t tag, const std::string &content, const streamid_t *streamid_p) {
	// Write the chunk header
	_write_chunk_header(tag, content.length(), streamid_p);
	// [Content]
	file_ << content;
}

void XDFWriter::_write_chunk_header(
	chunk_tag_t tag, std::size_t len, const streamid_t *streamid_p) {
	len += sizeof(chunk_tag_t);
	if (streamid_p) len += sizeof(streamid_t);

	// [Length] (variable-length integer, content + 2 bytes for the tag
	// + 4 bytes if the streamid is being written
	write_varlen_int(file_, len);
	// [Tag]
	write_little_endian(file_, static_cast<uint16_t>(tag));
	// Optional: [StreamId]
	if (streamid_p) write_little_endian(file_, *streamid_p);
}

void XDFWriter::write_stream_header(streamid_t streamid, const std::string &content) {
	std::lock_guard<std::mutex> lock(write_mut);
	_write_chunk(chunk_tag_t::streamheader, content, &streamid);
}

void XDFWriter::write_stream_footer(streamid_t streamid, const std::string &content) {
	std::lock_guard<std::mutex> lock(write_mut);
	_write_chunk(chunk_tag_t::streamfooter, content, &streamid);
}

void XDFWriter::write_stream_offset(streamid_t streamid, double now, double offset) {
	std::lock_guard<std::mutex> lock(write_mut);
	const auto len = sizeof(now) + sizeof(offset);
	_write_chunk_header(chunk_tag_t::clockoffset, len, &streamid);
	// [CollectionTime]
	write_little_endian(file_, now - offset);
	// [OffsetValue]
	write_little_endian(file_, offset);
}

void XDFWriter::write_boundary_chunk() {
	std::lock_guard<std::mutex> lock(write_mut);
	// the signature of the boundary chunk (next chunk begins right after this)
	const uint8_t boundary_uuid[] = {0x43, 0xA5, 0x46, 0xDC, 0xCB, 0xF5, 0x41, 0x0F, 0xB3, 0x0E,
		0xD5, 0x46, 0x73, 0x83, 0xCB, 0xE4};
	_write_chunk_header(chunk_tag_t::boundary, sizeof(boundary_uuid));
	write_sample_values(file_, boundary_uuid, sizeof(boundary_uuid));
}