First steps in CCNx packet coding. ccnx_encode* routines rewritten in NS3 style (using NS3::Buffer)

diff --git a/helper/ccnx-coding-helper.h b/helper/ccnx-coding-helper.h
new file mode 100644
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--- /dev/null
+++ b/helper/ccnx-coding-helper.h
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+/* -*- 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: Ilya Moiseenko <iliamo@cs.ucla.edu>
+ */
+
+#ifndef _CCNX_CODING_HELPER_H_
+#define _CCNX_CODING_HELPER_H_
+
+#include <sys/types.h>
+#include "ns3/ptr.h"
+#include "ns3/nstime.h"
+#include "ns3/buffer.h"
+
+namespace ns3 {
+
+namespace Name{ class Components; }
+
+class CcnxInterestHeader;
+class CcnxContentObjectHeader;
+  
+/**
+ * Helper to encode/decode ccnb formatted CCNx message
+ *
+ */
+class CcnxCodingHelper
+{
+public:
+  static size_t
+  Serialize (Buffer::Iterator start, const CcnxInterestHeader &interest);
+
+  static size_t
+  Serialize (Buffer::Iterator start, const CcnxContentObjectHeader &contentObject);
+
+private:
+  /**
+   * Type tag for a ccnb start marker.
+   *
+   * \see http://www.ccnx.org/releases/latest/doc/technical/DTAG.html
+   */
+  enum ccn_tt {
+    CCN_EXT,        /**< starts composite extension - numval is subtype */
+    CCN_TAG,        /**< starts composite - numval is tagnamelen-1 */ 
+    CCN_DTAG,       /**< starts composite - numval is tagdict index (enum ccn_dtag) */
+    CCN_ATTR,       /**< attribute - numval is attrnamelen-1, value follows */
+    CCN_DATTR,      /**< attribute numval is attrdict index */
+    CCN_BLOB,       /**< opaque binary data - numval is byte count */
+    CCN_UDATA,      /**< UTF-8 encoded character data - numval is byte count */
+    CCN_NO_TOKEN    /**< should not occur in encoding */
+  };
+
+  /** CCN_CLOSE terminates composites */
+  enum {CCN_CLOSE = 0};
+
+  // enum ccn_ext_subtype {
+  //   /* skip smallest values for now */
+  //   CCN_PROCESSING_INSTRUCTIONS = 16 /* <?name:U value:U?> */
+  // };
+
+  /**
+   * DTAG identifies ccnb-encoded elements.
+   *
+   * \see http://www.ccnx.org/releases/latest/doc/technical/DTAG.html
+   */
+  enum ccn_dtag {
+    CCN_DTAG_Any = 13,
+    CCN_DTAG_Name = 14,
+    CCN_DTAG_Component = 15,
+    CCN_DTAG_Certificate = 16,
+    CCN_DTAG_Collection = 17,
+    CCN_DTAG_CompleteName = 18,
+    CCN_DTAG_Content = 19,
+    CCN_DTAG_SignedInfo = 20,
+    CCN_DTAG_ContentDigest = 21,
+    CCN_DTAG_ContentHash = 22,
+    CCN_DTAG_Count = 24,
+    CCN_DTAG_Header = 25,
+    CCN_DTAG_Interest = 26,	/* 20090915 */
+    CCN_DTAG_Key = 27,
+    CCN_DTAG_KeyLocator = 28,
+    CCN_DTAG_KeyName = 29,
+    CCN_DTAG_Length = 30,
+    CCN_DTAG_Link = 31,
+    CCN_DTAG_LinkAuthenticator = 32,
+    CCN_DTAG_NameComponentCount = 33,	/* DeprecatedInInterest */
+    CCN_DTAG_RootDigest = 36,
+    CCN_DTAG_Signature = 37,
+    CCN_DTAG_Start = 38,
+    CCN_DTAG_Timestamp = 39,
+    CCN_DTAG_Type = 40,
+    CCN_DTAG_Nonce = 41,
+    CCN_DTAG_Scope = 42,
+    CCN_DTAG_Exclude = 43,
+    CCN_DTAG_Bloom = 44,
+    CCN_DTAG_BloomSeed = 45,
+    CCN_DTAG_AnswerOriginKind = 47,
+    CCN_DTAG_InterestLifetime = 48,
+    CCN_DTAG_Witness = 53,
+    CCN_DTAG_SignatureBits = 54,
+    CCN_DTAG_DigestAlgorithm = 55,
+    CCN_DTAG_BlockSize = 56,
+    CCN_DTAG_FreshnessSeconds = 58,
+    CCN_DTAG_FinalBlockID = 59,
+    CCN_DTAG_PublisherPublicKeyDigest = 60,
+    CCN_DTAG_PublisherCertificateDigest = 61,
+    CCN_DTAG_PublisherIssuerKeyDigest = 62,
+    CCN_DTAG_PublisherIssuerCertificateDigest = 63,
+    CCN_DTAG_ContentObject = 64,	/* 20090915 */
+    CCN_DTAG_WrappedKey = 65,
+    CCN_DTAG_WrappingKeyIdentifier = 66,
+    CCN_DTAG_WrapAlgorithm = 67,
+    CCN_DTAG_KeyAlgorithm = 68,
+    CCN_DTAG_Label = 69,
+    CCN_DTAG_EncryptedKey = 70,
+    CCN_DTAG_EncryptedNonceKey = 71,
+    CCN_DTAG_WrappingKeyName = 72,
+    CCN_DTAG_Action = 73,
+    CCN_DTAG_FaceID = 74,
+    CCN_DTAG_IPProto = 75,
+    CCN_DTAG_Host = 76,
+    CCN_DTAG_Port = 77,
+    CCN_DTAG_MulticastInterface = 78,
+    CCN_DTAG_ForwardingFlags = 79,
+    CCN_DTAG_FaceInstance = 80,
+    CCN_DTAG_ForwardingEntry = 81,
+    CCN_DTAG_MulticastTTL = 82,
+    CCN_DTAG_MinSuffixComponents = 83,
+    CCN_DTAG_MaxSuffixComponents = 84,
+    CCN_DTAG_ChildSelector = 85,
+    CCN_DTAG_RepositoryInfo = 86,
+    CCN_DTAG_Version = 87,
+    CCN_DTAG_RepositoryVersion = 88,
+    CCN_DTAG_GlobalPrefix = 89,
+    CCN_DTAG_LocalName = 90,
+    CCN_DTAG_Policy = 91,
+    CCN_DTAG_Namespace = 92,
+    CCN_DTAG_GlobalPrefixName = 93,
+    CCN_DTAG_PolicyVersion = 94,
+    CCN_DTAG_KeyValueSet = 95,
+    CCN_DTAG_KeyValuePair = 96,
+    CCN_DTAG_IntegerValue = 97,
+    CCN_DTAG_DecimalValue = 98,
+    CCN_DTAG_StringValue = 99,
+    CCN_DTAG_BinaryValue = 100,
+    CCN_DTAG_NameValue = 101,
+    CCN_DTAG_Entry = 102,
+    CCN_DTAG_ACL = 103,
+    CCN_DTAG_ParameterizedName = 104,
+    CCN_DTAG_Prefix = 105,
+    CCN_DTAG_Suffix = 106,
+    CCN_DTAG_Root = 107,
+    CCN_DTAG_ProfileName = 108,
+    CCN_DTAG_Parameters = 109,
+    CCN_DTAG_InfoString = 110,
+    CCN_DTAG_StatusResponse = 112,
+    CCN_DTAG_StatusCode = 113,
+    CCN_DTAG_StatusText = 114,
+    CCN_DTAG_SequenceNumber = 256,
+    CCN_DTAG_CCNProtocolDataUnit = 17702112
+  };
+
+  /**
+   * The decoder state is one of these, possibly with some
+   * additional bits set for internal use.  A complete parse
+   * ends up in state 0 or an error state.  Not all possible
+   * error states are listed here.
+   */
+  enum ccn_decoder_state {
+    CCN_DSTATE_INITIAL = 0,
+    CCN_DSTATE_NEWTOKEN,
+    CCN_DSTATE_NUMVAL,
+    CCN_DSTATE_UDATA,
+    CCN_DSTATE_TAGNAME,
+    CCN_DSTATE_ATTRNAME,
+    CCN_DSTATE_BLOB,
+    /* All error states are negative */
+    CCN_DSTATE_ERR_OVERFLOW = -1,
+    CCN_DSTATE_ERR_ATTR     = -2,       
+    CCN_DSTATE_ERR_CODING   = -3,
+    CCN_DSTATE_ERR_NEST     = -4, 
+    CCN_DSTATE_ERR_BUG      = -5
+  };
+
+
+private:
+  static size_t
+  AppendBlockHeader (Buffer::Iterator start, size_t value, ccn_tt block_type);
+
+  static size_t
+  AppendNumber (Buffer::Iterator start, uint32_t number);
+
+  static size_t
+  AppendCloser (Buffer::Iterator start);
+
+  static size_t
+  AppendName (Buffer::Iterator start, const Name::Components &name);
+
+  /**
+   * Append a binary timestamp as a BLOB using the ccn binary
+   * Timestamp representation (12-bit fraction).
+   *
+   * @param start start iterator of  the buffer to append to.
+   * @param time - Time object
+   *
+   * @returns written length
+   */
+  static size_t
+  AppendTimestampBlob (Buffer::Iterator start, Time time);
+
+  /**
+   * Append a tagged BLOB
+   *
+   * This is a ccnb-encoded element with containing the BLOB as content
+   *
+   * @param start start iterator of  the buffer to append to.
+   * @param dtag is the element's dtab
+   * @param data points to the binary data
+   * @param size is the size of the data, in bytes
+   *
+   * @returns written length
+   */
+  static size_t
+  AppendTaggedBlob (Buffer::Iterator start, ccn_dtag dtag,
+                    const uint8_t *data, size_t size);
+  
+};
+
+} // namespace ns3
+
+#endif // _CCNX_CODING_HELPER_H_
+