protected Header readHeaderFromBuffer(ByteBuffer buffer) throws WWRuntimeException {
// Read file code - first byte
int fileCode = buffer.get();
if (fileCode > 5) {
String message = Logging.getMessage("SHP.NotADBaseFile", file.getPath());
Logging.logger().log(java.util.logging.Level.SEVERE, message);
throw new WWRuntimeException(message);
}
// Last update date
int yy = 0xFF & buffer.get(); // unsigned
int mm = buffer.get();
int dd = buffer.get();
// Number of records
int numRecords = buffer.getInt();
// Header struct length
int headerLength = buffer.getShort();
// Record length
int recordLength = buffer.getShort();
// Assemble header
Header header = new Header();
header.fileCode = fileCode;
Calendar cal = Calendar.getInstance();
cal.set(1900 + yy, mm - 1, dd);
header.lastModificationDate = cal.getTime();
header.numberOfRecords = numRecords;
header.headerLength = headerLength;
header.recordLength = recordLength;
return header;
}
protected Header readHeaderFromStream(InputStream is) throws IOException {
ReadableByteChannel channel = Channels.newChannel(is);
// Read header fixed portion
ByteBuffer headerBuffer = ShapefileUtils.readByteChannelToBuffer(channel, FIXED_HEADER_LENGTH);
Header header = this.readHeaderFromBuffer(headerBuffer);
// Read fields description header
int fieldsHeaderLength = header.headerLength - FIXED_HEADER_LENGTH;
header.fieldsHeaderBuffer = ShapefileUtils.readByteChannelToBuffer(channel, fieldsHeaderLength);
return header;
}