/**
* "Parse the supplied chunk of arriving data and append it to the rcvd_blocks_ list in the given
* bundle, finding the appropriate BlockProcessor element and calling its receive() handler.
*
* <p>When called repeatedly for arriving chunks of data, this properly fills in the entire
* bundle, including the in_blocks_ record of the arriving blocks and the payload (which is stored
* externally)." [DTN2]
*
* @return "the length of data consumed or -1 on protocol error, plus sets last to true if the
* bundle is complete." [DTN2]
*/
public static int consume(Bundle bundle, IByteBuffer data, int len, boolean[] last) {
int old_position = data.position();
int origlen = len;
last[0] = false;
BlockInfoVec recv_blocks = bundle.recv_blocks();
// "special case for first time we get called, since we need to
// create a BlockInfo struct for the primary block without knowing
// the typecode or the length" [DTN2]
if (recv_blocks.isEmpty()) {
BPF.getInstance()
.getBPFLogger()
.debug(TAG, "consume: got first block... " + "creating primary block info");
recv_blocks.append_block(find_processor(bundle_block_type_t.PRIMARY_BLOCK), null);
}
// "loop as long as there is data left to process" [DTN2]
while (len != 0) {
BPF.getInstance()
.getBPFLogger()
.debug(TAG, String.format("consume: %d bytes left to process", len));
BlockInfo info = recv_blocks.back();
// "if the last received block is complete, create a new one
// and push it onto the vector. at this stage we consume all
// blocks, even if there's no BlockProcessor that understands
// how to parse it" [DTN2]
if (info.complete()) {
data.mark();
byte bundle_block_type_byte = data.get();
bundle_block_type_t type = bundle_block_type_t.get(bundle_block_type_byte);
data.reset();
info = recv_blocks.append_block(find_processor(type), null);
BPF.getInstance()
.getBPFLogger()
.debug(
TAG,
String.format(
"consume: previous block complete, " + "created new BlockInfo type %s",
info.owner().block_type()));
}
// "now we know that the block isn't complete, so we tell it to
// consume a chunk of data" [DTN2]
BPF.getInstance()
.getBPFLogger()
.debug(
TAG,
String.format(
"consume: block processor %s type %s incomplete, "
+ "calling consume (%d bytes already buffered)",
info.owner().block_type(), info.type(), info.contents().position()));
int cc = info.owner().consume(bundle, info, data, len);
if (cc < 0) {
BPF.getInstance()
.getBPFLogger()
.error(TAG, String.format("consume: protocol error handling block %s", info.type()));
return -1;
}
// "decrement the amount that was just handled from the overall
// total. verify that the block was either completed or
// consumed all the data that was passed in." [DTN2]
len -= cc;
data.position(data.position() + cc);
BPF.getInstance()
.getBPFLogger()
.debug(
TAG,
String.format(
"consume: consumed %d bytes of block type %s (%s)",
cc, info.type(), info.complete() ? "complete" : "not complete"));
if (info.complete()) {
// check if we're done with the bundle
if ((info.flags() & block_flag_t.BLOCK_FLAG_LAST_BLOCK.getCode()) > 0) {
last[0] = true;
break;
}
} else {
assert (len == 0);
}
}
BPF.getInstance()
.getBPFLogger()
.debug(
TAG,
String.format(
"bundle id %d consume completed, %d/%d bytes consumed %s",
bundle.bundleid(), origlen - len, origlen, last[0] ? "(completed bundle)" : ""));
data.position(old_position);
return origlen - len;
}
/**
* "Copies out a chunk of formatted bundle data at a specified offset from the provided
* BlockInfoVec." [DTN2]
*
* @return "the length of the chunk produced (up to the supplied length) and sets last to true if
* the bundle is complete." [DTN2]
*/
public static int produce(
final Bundle bundle,
final BlockInfoVec blocks,
IByteBuffer data,
int offset,
int len,
boolean[] last) {
int old_position = data.position();
int origlen = len;
last[0] = false;
if (len == 0) return 0;
assert (!blocks.isEmpty());
Iterator<BlockInfo> iter = blocks.iterator();
BlockInfo current_block = iter.next();
// "advance past any blocks that are skipped by the given offset."[DTN2]
while (offset >= current_block.full_length()) {
BPF.getInstance()
.getBPFLogger()
.debug(
TAG,
String.format(
"BundleProtocol::produce skipping block type %s "
+ "since offset %d >= block length %d",
current_block.type().toString(), offset, current_block.full_length()));
offset -= current_block.full_length();
current_block = iter.next();
}
// "the offset value now should be within the current block" [DTN2]
while (true) {
// The first time remainder will be minus from leftover offset above
// but later on it will be the full content of the block
int remainder = current_block.full_length() - offset;
int tocopy = Math.min(len, remainder);
BPF.getInstance()
.getBPFLogger()
.debug(
TAG,
String.format(
"BundleProtocol::produce copying %d/%d bytes from "
+ "block type %s at offset %d",
tocopy, remainder, current_block.type().toString(), offset));
current_block.owner().produce(bundle, current_block, data, offset, tocopy);
len -= tocopy;
// move the position of IByteBuffer
data.position(data.position() + tocopy);
// "if we've copied out the full amount the user asked for,
// we're done. note that we need to check the corner case
// where we completed the block exactly to properly set the
// last bit" [DTN2]
if (len == 0) {
if ((tocopy == remainder)
&& ((current_block.flags()
& BundleProtocol.block_flag_t.BLOCK_FLAG_LAST_BLOCK.getCode())
> 0)) {
last[0] = true;
}
break;
}
// "we completed the current block, so we're done if this
// is the last block, even if there's space in the user buffer"
// [DTN2]
assert (tocopy == remainder);
if ((current_block.flags() & BundleProtocol.block_flag_t.BLOCK_FLAG_LAST_BLOCK.getCode())
> 0) {
last[0] = true;
break;
}
// advance to next block
current_block = iter.next();
offset = 0;
}
BPF.getInstance()
.getBPFLogger()
.debug(
TAG,
String.format(
"BundleProtocol::produce complete: "
+ "produced %d bytes, bundle id %d, status is %s",
origlen - len, bundle.bundleid(), last[0] ? "complete" : "not complete"));
data.position(old_position);
return origlen - len;
}