void Header::WriteLAS10PadSignature()
{
// Only write pad signature bytes for LAS 1.0 files. Any other files
// will not get the pad bytes and we are *not* allowing anyone to
// override this either - hobu
if (m_header.GetVersionMinor() > 0) {
return;
}
int32_t diff = m_header.GetDataOffset() - GetRequiredHeaderSize();
if (diff < 2) {
std::ostringstream oss;
oss << "Header is not large enough to write extra 1.0 pad bytes. Data offset is ";
oss << m_header.GetDataOffset() << " while the required total size ";
oss << "for the VLRs is " << GetRequiredHeaderSize();
throw std::runtime_error(oss.str());
}
// step back two bytes to write the pad bytes. We should have already
// determined by this point if a) they will fit b) they won't overwrite
// exiting real data
GetStream().seekp(m_header.GetDataOffset() - 2, std::ios::beg);
// Write the pad bytes.
uint8_t const sgn1 = 0xCC;
uint8_t const sgn2 = 0xDD;
detail::write_n(GetStream(), sgn1, sizeof(uint8_t));
detail::write_n(GetStream(), sgn2, sizeof(uint8_t));
}
void Header::WriteLAS10PadSignature()
{
// Only write pad signature bytes for LAS 1.0 files. Any other files
// will not get the pad bytes and we are *not* allowing anyone to
// override this either - hobu
if (m_header.GetVersionMinor() > 0) {
return;
}
int32_t diff = m_header.GetDataOffset() - GetRequiredHeaderSize();
if (diff < 2) {
m_header.SetDataOffset(m_header.GetDataOffset() + 2);
// Seek to the location of the data offset in the header and write a new one.
m_ofs.seekp(96, std::ios::beg);
detail::write_n(m_ofs, m_header.GetDataOffset(), sizeof(m_header.GetDataOffset()));
}
// step back two bytes to write the pad bytes. We should have already
// determined by this point if a) they will fit b) they won't overwrite
// exiting real data
m_ofs.seekp(m_header.GetDataOffset() - 2, std::ios::beg);
// Write the pad bytes.
uint8_t const sgn1 = 0xCC;
uint8_t const sgn2 = 0xDD;
detail::write_n(m_ofs, sgn1, sizeof(uint8_t));
detail::write_n(m_ofs, sgn2, sizeof(uint8_t));
}
void Header::WriteVLRs()
{
// Seek to the end of the public header block (beginning of the VLRs)
// to start writing
m_ofs.seekp(m_header.GetHeaderSize(), std::ios::beg);
int32_t diff = m_header.GetDataOffset() - GetRequiredHeaderSize();
if (diff < 0) {
m_header.SetDataOffset(GetRequiredHeaderSize());
// Seek to the location of the data offset in the header and write a new one.
m_ofs.seekp(96, std::ios::beg);
detail::write_n(m_ofs, m_header.GetDataOffset(), sizeof(m_header.GetDataOffset()));
m_ofs.seekp(m_header.GetHeaderSize(), std::ios::beg);
// std::ostringstream oss;
// oss << "Header is not large enough to contain VLRs. Data offset is ";
// oss << m_header.GetDataOffset() << " while the required total size ";
// oss << "for the VLRs is " << GetRequiredHeaderSize();
// throw std::runtime_error(oss.str());
}
for (uint32_t i = 0; i < m_header.GetRecordsCount(); ++i)
{
VariableRecord const &vlr = m_header.GetVLR(i);
detail::write_n(m_ofs, vlr.GetReserved(), sizeof(uint16_t));
detail::write_n(m_ofs, vlr.GetUserId(true).c_str(), 16);
detail::write_n(m_ofs, vlr.GetRecordId(), sizeof(uint16_t));
detail::write_n(m_ofs, vlr.GetRecordLength(), sizeof(uint16_t));
detail::write_n(m_ofs, vlr.GetDescription(true).c_str(), 32);
std::vector<uint8_t> const& data = vlr.GetData();
std::streamsize const size = static_cast<std::streamsize>(data.size());
if(size > 0)
{
detail::write_n(m_ofs, data.front(), size);
}
}
}
void Header::WriteVLRs()
{
// Seek to the end of the public header block (beginning of the VLRs)
// to start writing
GetStream().seekp(m_header.GetHeaderSize(), std::ios::beg);
int32_t diff = m_header.GetDataOffset() - GetRequiredHeaderSize();
if (diff < 0) {
std::ostringstream oss;
oss << "Header is not large enough to contain VLRs. Data offset is ";
oss << m_header.GetDataOffset() << " while the required total size ";
oss << "for the VLRs is " << GetRequiredHeaderSize();
throw std::runtime_error(oss.str());
}
for (uint32_t i = 0; i < m_header.GetRecordsCount(); ++i)
{
VariableRecord const &vlr = m_header.GetVLR(i);
detail::write_n(GetStream(), vlr.GetReserved(), sizeof(uint16_t));
detail::write_n(GetStream(), vlr.GetUserId(true).c_str(), 16);
detail::write_n(GetStream(), vlr.GetRecordId(), sizeof(uint16_t));
detail::write_n(GetStream(), vlr.GetRecordLength(), sizeof(uint16_t));
detail::write_n(GetStream(), vlr.GetDescription(true).c_str(), 32);
std::vector<uint8_t> const& data = vlr.GetData();
std::streamsize const size = static_cast<std::streamsize>(data.size());
detail::write_n(GetStream(), data.front(), size);
}
// if we had more room than we need for the VLRs, we need to pad that with
// 0's. We must also not forget to add the 1.0 pad bytes to the end of this
// but the impl should be the one doing that, not us.
if (diff > 0) {
detail::write_n(GetStream(), "\0", diff);
}
}
void Header::write()
{
uint8_t n1 = 0;
uint16_t n2 = 0;
uint32_t n4 = 0;
// Figure out how many points we already have.
// Figure out if we're in append mode. If we are, we can't rewrite
// any of the VLRs including the Schema and SpatialReference ones.
bool bAppendMode = false;
// This test should only be true if we were opened in both
// std::ios::in *and* std::ios::out
// Seek to the beginning
GetStream().seekp(0, ios::beg);
ios::pos_type begin = GetStream().tellp();
// Seek to the end
GetStream().seekp(0, ios::end);
ios::pos_type end = GetStream().tellp();
if ((begin != end) && (end != static_cast<ios::pos_type>(0))) {
bAppendMode = true;
}
// If we are in append mode, we are not touching *any* VLRs.
if (bAppendMode)
{
// We're opened in append mode
ios::off_type points = end - static_cast<ios::off_type>(m_header.GetDataOffset());
ios::off_type count = points / static_cast<ios::off_type>(m_header.GetDataRecordLength());
if (points < 0) {
std::ostringstream oss;
oss << "The header's data offset," << m_header.GetDataOffset()
<<", is much larger than the size of the file, " << end
<<", and something is amiss. Did you use the right header"
<<" offset value?";
throw std::runtime_error(oss.str());
}
uint32_t& cnt = GetPointCount();
cnt = static_cast<uint32_t>(count);
SetPointCount(cnt);
// Position to the beginning of the file to start writing the header
GetStream().seekp(0, ios::beg);
}
else
{
// Rewrite the georeference VLR entries if they exist
m_header.SetGeoreference();
// If we have a custom schema, add the VLR and write it into the
// file.
if (m_header.GetSchema().IsCustom()) {
// Wipe any schema-related VLRs we might have, as this is now out of date.
m_header.DeleteVLRs("liblas", 7);
VariableRecord v = m_header.GetSchema().GetVLR();
std::cout << m_header.GetSchema()<< std::endl;
m_header.AddVLR(v);
}
int32_t difference = m_header.GetDataOffset() - GetRequiredHeaderSize();
if (difference <= 0)
{
int32_t d = abs(difference);
if (m_header.GetVersionMinor() == 0)
{
// Add the two extra bytes for the 1.0 pad
d = d + 2;
}
m_header.SetDataOffset(m_header.GetDataOffset() + d );
}
}
// 1. File Signature
std::string const filesig(m_header.GetFileSignature());
assert(filesig.size() == 4);
detail::write_n(GetStream(), filesig, 4);
// 2. File SourceId / Reserved
if (m_header.GetVersionMinor() == 0) {
n4 = m_header.GetReserved();
detail::write_n(GetStream(), n4, sizeof(n4));
} else if (m_header.GetVersionMinor() > 0) {
n2 = m_header.GetFileSourceId();
detail::write_n(GetStream(), n2, sizeof(n2));
n2 = m_header.GetReserved();
detail::write_n(GetStream(), n2, sizeof(n2));
}
// 3-6. GUID data
uint32_t d1 = 0;
uint16_t d2 = 0;
uint16_t d3 = 0;
uint8_t d4[8] = { 0 };
liblas::guid g = m_header.GetProjectId();
g.output_data(d1, d2, d3, d4);
detail::write_n(GetStream(), d1, sizeof(d1));
detail::write_n(GetStream(), d2, sizeof(d2));
detail::write_n(GetStream(), d3, sizeof(d3));
detail::write_n(GetStream(), d4, sizeof(d4));
// 7. Version major
n1 = m_header.GetVersionMajor();
assert(1 == n1);
detail::write_n(GetStream(), n1, sizeof(n1));
// 8. Version minor
n1 = m_header.GetVersionMinor();
detail::write_n(GetStream(), n1, sizeof(n1));
// 9. System ID
std::string sysid(m_header.GetSystemId(true));
assert(sysid.size() == 32);
detail::write_n(GetStream(), sysid, 32);
// 10. Generating Software ID
std::string softid(m_header.GetSoftwareId(true));
assert(softid.size() == 32);
detail::write_n(GetStream(), softid, 32);
// 11. Flight Date Julian
n2 = m_header.GetCreationDOY();
detail::write_n(GetStream(), n2, sizeof(n2));
// 12. Year
n2 = m_header.GetCreationYear();
detail::write_n(GetStream(), n2, sizeof(n2));
// 13. Header Size
n2 = m_header.GetHeaderSize();
assert(227 <= n2);
detail::write_n(GetStream(), n2, sizeof(n2));
// 14. Offset to data
n4 = m_header.GetDataOffset();
detail::write_n(GetStream(), n4, sizeof(n4));
// 15. Number of variable length records
n4 = m_header.GetRecordsCount();
detail::write_n(GetStream(), n4, sizeof(n4));
// 16. Point Data Format ID
n1 = static_cast<uint8_t>(m_header.GetDataFormatId());
detail::write_n(GetStream(), n1, sizeof(n1));
// 17. Point Data Record Length
n2 = m_header.GetDataRecordLength();
detail::write_n(GetStream(), n2, sizeof(n2));
// 18. Number of point records
// This value is updated if necessary, see UpdateHeader function.
n4 = m_header.GetPointRecordsCount();
detail::write_n(GetStream(), n4, sizeof(n4));
// 19. Number of points by return
std::vector<uint32_t>::size_type const srbyr = 5;
std::vector<uint32_t> const& vpbr = m_header.GetPointRecordsByReturnCount();
// TODO: fix this for 1.3, which has srbyr = 7; See detail/reader/header.cpp for more details
// assert(vpbr.size() <= srbyr);
uint32_t pbr[srbyr] = { 0 };
std::copy(vpbr.begin(), vpbr.begin() + srbyr, pbr); // FIXME: currently, copies only 5 records, to be improved
detail::write_n(GetStream(), pbr, sizeof(pbr));
// 20-22. Scale factors
detail::write_n(GetStream(), m_header.GetScaleX(), sizeof(double));
detail::write_n(GetStream(), m_header.GetScaleY(), sizeof(double));
detail::write_n(GetStream(), m_header.GetScaleZ(), sizeof(double));
// 23-25. Offsets
detail::write_n(GetStream(), m_header.GetOffsetX(), sizeof(double));
detail::write_n(GetStream(), m_header.GetOffsetY(), sizeof(double));
detail::write_n(GetStream(), m_header.GetOffsetZ(), sizeof(double));
// 26-27. Max/Min X
detail::write_n(GetStream(), m_header.GetMaxX(), sizeof(double));
detail::write_n(GetStream(), m_header.GetMinX(), sizeof(double));
// 28-29. Max/Min Y
detail::write_n(GetStream(), m_header.GetMaxY(), sizeof(double));
detail::write_n(GetStream(), m_header.GetMinY(), sizeof(double));
// 30-31. Max/Min Z
detail::write_n(GetStream(), m_header.GetMaxZ(), sizeof(double));
detail::write_n(GetStream(), m_header.GetMinZ(), sizeof(double));
// If WriteVLR returns a value, it is because the header's
// offset is not large enough to contain the VLRs. The value
// it returns is the number of bytes we must increase the header
// by in order for it to contain the VLRs. We do not touch VLRs if we
// are in append mode.
if (!bAppendMode)
{
WriteVLRs();
// Write the 1.0 pad signature if we need to.
WriteLAS10PadSignature();
}
// If we already have points, we're going to put it at the end of the file.
// If we don't have any points, we're going to leave it where it is.
if (GetPointCount() != 0)
GetStream().seekp(0, std::ios::end);
}
