First steps in CCNx packet coding. ccnx_encode* routines rewritten in NS3 style (using NS3::Buffer)
diff --git a/helper/ccnx-coding-helper.cc b/helper/ccnx-coding-helper.cc
new file mode 100644
index 0000000..6899543
--- /dev/null
+++ b/helper/ccnx-coding-helper.cc
@@ -0,0 +1,223 @@
+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2011 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author:
+ */
+
+#include "ccnx-coding-helper.h"
+
+#include "ns3/name-components.h"
+#include "ns3/ccnx-interest-header.h"
+#include "ns3/ccnx-content-object-header.h"
+
+#include <sstream>
+
+namespace ns3 {
+
+#define CCN_TT_BITS 3
+#define CCN_TT_MASK ((1 << CCN_TT_BITS) - 1)
+#define CCN_MAX_TINY ((1 << (7-CCN_TT_BITS)) - 1)
+#define CCN_TT_HBIT ((unsigned char)(1 << 7))
+
+size_t
+CcnxCodingHelper::AppendBlockHeader (Buffer::Iterator start, size_t val, enum ccn_tt tt)
+{
+ unsigned char buf[1+8*((sizeof(val)+6)/7)];
+ unsigned char *p = &(buf[sizeof(buf)-1]);
+ size_t n = 1;
+ p[0] = (CCN_TT_HBIT & ~CCN_CLOSE) |
+ ((val & CCN_MAX_TINY) << CCN_TT_BITS) |
+ (CCN_TT_MASK & tt);
+ val >>= (7-CCN_TT_BITS);
+ while (val != 0) {
+ (--p)[0] = (((unsigned char)val) & ~CCN_TT_HBIT) | CCN_CLOSE;
+ n++;
+ val >>= 7;
+ }
+ start.Write (p,n);
+ return n;
+}
+
+size_t
+CcnxCodingHelper::AppendNumber (Buffer::Iterator start, uint32_t number)
+{
+ std::ostringstream os;
+ os << number;
+
+ size_t written = 0;
+ written += AppendBlockHeader (start, os.str().size(), CCN_UDATA);
+ written += os.str().size();
+ start.Write (reinterpret_cast<const unsigned char*>(os.str().c_str()), os.str().size());
+
+ return written;
+}
+
+
+size_t
+CcnxCodingHelper::CcnxCodingHelper::AppendCloser (Buffer::Iterator start)
+{
+ start.WriteU8 (CCN_CLOSE);
+ return 1;
+}
+
+size_t
+CcnxCodingHelper::AppendName (Buffer::Iterator start, const Name::Components &name)
+{
+ return 0;
+}
+
+size_t
+CcnxCodingHelper::AppendTimestampBlob (Buffer::Iterator start, Time time)
+{
+ // the original function implements Markers... thought not sure what are these markers for...
+
+ // Determine miminal number of bytes required to store the timestamp
+ int required_bytes = 2; // 12 bits for fractions of a second, 4 bits left for seconds. Sometimes it is enough
+ intmax_t ts = time.ToInteger (Time::S) >> 4;
+ for (; required_bytes < 7 && ts != 0; ts >>= 8) // not more than 6 bytes?
+ required_bytes++;
+
+ size_t len = AppendBlockHeader(start, required_bytes, CCN_BLOB);
+
+ // write part with seconds
+ ts = time.ToInteger (Time::S) >> 4;
+ for (int i = 0; i < required_bytes - 2; i++)
+ start.WriteU8 ( ts >> (8 * (required_bytes - 3 - i)) );
+
+ /* arithmetic contortions are to avoid overflowing 31 bits */
+ ts = ((time.ToInteger (Time::S) & 15) << 12) + ((time.ToInteger (Time::NS) / 5 * 8 + 195312) / 390625);
+ for (int i = required_bytes - 2; i < required_bytes; i++)
+ start.WriteU8 ( ts >> (8 * (required_bytes - 1 - i)) );
+
+ return len + required_bytes;
+}
+
+size_t
+CcnxCodingHelper::AppendTaggedBlob (Buffer::Iterator start, ccn_dtag dtag,
+ const uint8_t *data, size_t size)
+{
+ size_t written = AppendBlockHeader (start, dtag, CCN_DTAG);
+ if (size>0)
+ {
+ written += AppendBlockHeader (start, size, CCN_BLOB);
+ start.Write (data, size);
+ written += size;
+ }
+ written += AppendCloser (start);
+
+ return written;
+}
+
+
+size_t
+CcnxCodingHelper::Serialize (Buffer::Iterator start, const CcnxInterestHeader &interest)
+{
+ size_t written = 0;
+ written += AppendBlockHeader (start, CCN_DTAG_Interest, CCN_DTAG); // <Interest>
+
+ written += AppendBlockHeader (start, CCN_DTAG_Name, CCN_DTAG); // <Name>
+ written += AppendName (start, interest.GetName()); // <Component>...</Component>...
+ written += AppendCloser (start); // </Name>
+
+ if (interest.GetMinSuffixComponents() >= 0)
+ {
+ written += AppendBlockHeader (start, CCN_DTAG_MinSuffixComponents, CCN_DTAG);
+ written += AppendNumber (start, interest.GetMinSuffixComponents ());
+ written += AppendCloser (start);
+ }
+ if (interest.GetMaxSuffixComponents() >= 0)
+ {
+ written += AppendBlockHeader (start, CCN_DTAG_MaxSuffixComponents, CCN_DTAG);
+ written += AppendNumber (start, interest.GetMaxSuffixComponents ());
+ written += AppendCloser (start);
+ }
+ if (interest.GetExclude().size() > 0)
+ {
+ written += AppendBlockHeader (start, CCN_DTAG_Exclude, CCN_DTAG); // <Exclude>
+ written += AppendName (start, interest.GetExclude()); // <Component>...</Component>...
+ written += AppendCloser (start); // </Exclude>
+ }
+ if (interest.IsEnabledChildSelector())
+ {
+ written += AppendBlockHeader (start, CCN_DTAG_ChildSelector, CCN_DTAG);
+ written += AppendNumber (start, 1);
+ written += AppendCloser (start);
+ }
+ if (interest.IsEnabledAnswerOriginKind())
+ {
+ written += AppendBlockHeader (start, CCN_DTAG_AnswerOriginKind, CCN_DTAG);
+ written += AppendNumber (start, 1);
+ written += AppendCloser (start);
+ }
+ if (interest.GetScope() >= 0)
+ {
+ written += AppendBlockHeader (start, CCN_DTAG_Scope, CCN_DTAG);
+ written += AppendNumber (start, interest.GetScope ());
+ written += AppendCloser (start);
+ }
+ if (!interest.GetInterestLifetime().IsZero())
+ {
+ written += AppendBlockHeader (start, CCN_DTAG_InterestLifetime, CCN_DTAG);
+ written += AppendTimestampBlob (start, interest.GetInterestLifetime());
+ written += AppendCloser (start);
+ }
+ if (interest.GetNonce()>0)
+ {
+ uint32_t nonce = interest.GetNonce();
+ written += AppendTaggedBlob (start, CCN_DTAG_Nonce,
+ reinterpret_cast<const uint8_t*>(&nonce),
+ sizeof(nonce));
+ }
+ written += AppendCloser (start); // </Interest>
+
+ return written;
+}
+
+size_t
+CcnxCodingHelper::Serialize (Buffer::Iterator start, const CcnxContentObjectHeader &contentObject)
+{
+ size_t written = 0;
+ written += AppendBlockHeader (start, CCN_DTAG_ContentObject, CCN_DTAG); // <ContentObject>
+
+ // fake signature
+ written += AppendBlockHeader (start, CCN_DTAG_Signature, CCN_DTAG); // <Signature>
+ // Signature ::= DigestAlgorithm?
+ // Witness?
+ // SignatureBits
+ written += AppendTaggedBlob (start, CCN_DTAG_SignatureBits, 0, 0); // <SignatureBits />
+ written += AppendCloser (start); // </Signature>
+
+ written += AppendName (start, contentObject.GetName()); // <Name><Component>...</Component>...</Name>
+
+ // fake signature
+ written += AppendBlockHeader (start, CCN_DTAG_SignedInfo, CCN_DTAG); // <SignedInfo>
+ // SignedInfo ::= PublisherPublicKeyDigest
+ // Timestamp
+ // Type?
+ // FreshnessSeconds?
+ // FinalBlockID?
+ // KeyLocator?
+ written += AppendTaggedBlob (start, CCN_DTAG_PublisherPublicKeyDigest, 0, 0); // <PublisherPublicKeyDigest />
+ written += AppendCloser (start); // </SignedInfo>
+
+ written += AppendBlockHeader (start, CCN_DTAG_Content, CCN_DTAG); // <Content>
+
+ // there is no closing tag !!!
+ return written;
+}
+
+} // namespace ns3