private void readSegments()
{
int saveOffset = this.buffer.position();
int nextSegmentOffset = this.fileHeader.getHeaderLength();
// parse Image Description Group
nextSegmentOffset = parseSegment(NITFSSegmentType.IMAGE_SEGMENT, nextSegmentOffset);
// parse Graphic/Symbol Description Group
nextSegmentOffset = parseSegment(NITFSSegmentType.SYMBOL_SEGMENT, nextSegmentOffset);
// parse Label Description Group
nextSegmentOffset = parseSegment(NITFSSegmentType.LABEL_SEGMENT, nextSegmentOffset);
// parse Text Description Group
nextSegmentOffset = parseSegment(NITFSSegmentType.TEXT_SEGMENT, nextSegmentOffset);
// parse Data Extension Description Group
nextSegmentOffset = parseSegment(NITFSSegmentType.DATA_EXTENSION_SEGMENT, nextSegmentOffset);
// parse Reserved Extension Description Group
nextSegmentOffset = parseSegment(NITFSSegmentType.RESERVED_EXTENSION_SEGMENT, nextSegmentOffset);
// parse User Defined Header Description (UDHD) Group
NITFSUserDefinedHeaderSegment userHeaderSeg = new RPFUserDefinedHeaderSegment(this.buffer);
this.segments.add(userHeaderSeg);
nextSegmentOffset += userHeaderSeg.headerLength + userHeaderSeg.dataLength;
// parse Extended Header Description Group
nextSegmentOffset = parseSegment(NITFSSegmentType.EXTENDED_HEADER_SEGMENT, nextSegmentOffset);
// let's read each header
for (NITFSSegment segment : segments)
{
//
// String segId = NITFSUtil.getString(buffer, segment.headerStartOffset, 2);
// System.out.println("Segment type=" + segment.segmentType + ", id=" + segId);
}
}
private int parseSegment(NITFSSegmentType segType, int nextSegmentOffset)
{
int headerLengthSize = segType.getHeaderLengthSize();
int dataLengthSize = segType.getDataLengthSize();
int numOfSegments = Integer.parseInt(NITFSUtil.getString(this.buffer, 3));
for (int i = 0; i < numOfSegments; i++)
{
int segHeaderLength = Integer.parseInt(NITFSUtil.getString(this.buffer, headerLengthSize));
int seqDataLength = Integer.parseInt(NITFSUtil.getString(this.buffer, dataLengthSize));
int saveOffset = this.buffer.position(); // pass buffer to NITFSSegment to parse their headers' contents
NITFSSegment segment;
switch (segType)
{
case IMAGE_SEGMENT:
segment = new NITFSImageSegment(this.buffer, nextSegmentOffset, segHeaderLength,
nextSegmentOffset + segHeaderLength, seqDataLength);
break;
case SYMBOL_SEGMENT:
segment = new NITFSSymbolSegment(this.buffer, nextSegmentOffset, segHeaderLength,
nextSegmentOffset + segHeaderLength, seqDataLength);
break;
case LABEL_SEGMENT:
segment = new NITFSLabelSegment(this.buffer, nextSegmentOffset, segHeaderLength,
nextSegmentOffset + segHeaderLength, seqDataLength);
break;
case TEXT_SEGMENT:
segment = new NITFSTextSegment(this.buffer, nextSegmentOffset, segHeaderLength,
nextSegmentOffset + segHeaderLength, seqDataLength);
break;
case DATA_EXTENSION_SEGMENT:
segment = new NITFSDataExtensionSegment(this.buffer, nextSegmentOffset, segHeaderLength,
nextSegmentOffset + segHeaderLength, seqDataLength);
break;
case RESERVED_EXTENSION_SEGMENT:
segment = new NITFSReservedExtensionSegment(this.buffer, nextSegmentOffset, segHeaderLength,
nextSegmentOffset + segHeaderLength, seqDataLength);
break;
case USER_DEFINED_HEADER_SEGMENT:
segment = new RPFUserDefinedHeaderSegment(this.buffer);
break;
case EXTENDED_HEADER_SEGMENT: // // throw exception - wrong parser for EXTENDED_HEADER_SEGMENT
segment = new NITFSExtendedHeaderSegment(this.buffer, nextSegmentOffset, segHeaderLength,
nextSegmentOffset + segHeaderLength, seqDataLength);
break;
default:
throw new NITFSRuntimeException("NITFSReader.UnknownOrUnsupportedSegment", segType.ToString());
}
this.segments.add(segment);
nextSegmentOffset += segHeaderLength + seqDataLength;
buffer.position(saveOffset); // restore offset
}
return(nextSegmentOffset);
}