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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:
*/
#include "ccnx-encoding-helper.h"
#include "ns3/name-components.h"
#include "ns3/ccnx-interest-header.h"
#include "ns3/ccnx-content-object-header.h"
#include <sstream>
#include <boost/foreach.hpp>
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
CcnxEncodingHelper::AppendBlockHeader (Buffer::Iterator start, size_t val, CcnbParser::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 & ~CcnbParser::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) | CcnbParser::CCN_CLOSE;
n++;
val >>= 7;
}
start.Write (p,n);
return n;
}
size_t
CcnxEncodingHelper::AppendNumber (Buffer::Iterator start, uint32_t number)
{
std::ostringstream os;
os << number;
size_t written = 0;
written += AppendBlockHeader (start, os.str().size(), CcnbParser::CCN_UDATA);
written += os.str().size();
start.Write (reinterpret_cast<const unsigned char*>(os.str().c_str()), os.str().size());
return written;
}
size_t
CcnxEncodingHelper::CcnxEncodingHelper::AppendCloser (Buffer::Iterator start)
{
start.WriteU8 (CcnbParser::CCN_CLOSE);
return 1;
}
size_t
CcnxEncodingHelper::AppendNameComponents (Buffer::Iterator start, const CcnxNameComponents &name)
{
size_t written = 0;
BOOST_FOREACH (const std::string &component, name.GetComponents())
{
written += AppendTaggedBlob (start, CcnbParser::CCN_DTAG_Component,
reinterpret_cast<const uint8_t*>(component.c_str()), component.size());
}
return written;
}
size_t
CcnxEncodingHelper::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, CcnbParser::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
CcnxEncodingHelper::AppendTaggedBlob (Buffer::Iterator start, CcnbParser::ccn_dtag dtag,
const uint8_t *data, size_t size)
{
size_t written = AppendBlockHeader (start, dtag, CcnbParser::CCN_DTAG);
if (size>0)
{
written += AppendBlockHeader (start, size, CcnbParser::CCN_BLOB);
start.Write (data, size);
written += size;
}
written += AppendCloser (start);
return written;
}
size_t
CcnxEncodingHelper::Serialize (Buffer::Iterator start, const CcnxInterestHeader &interest)
{
size_t written = 0;
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Interest, CcnbParser::CCN_DTAG); // <Interest>
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Name, CcnbParser::CCN_DTAG); // <Name>
written += AppendNameComponents (start, interest.GetName()); // <Component>...</Component>...
written += AppendCloser (start); // </Name>
if (interest.GetMinSuffixComponents() >= 0)
{
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_MinSuffixComponents, CcnbParser::CCN_DTAG);
written += AppendNumber (start, interest.GetMinSuffixComponents ());
written += AppendCloser (start);
}
if (interest.GetMaxSuffixComponents() >= 0)
{
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_MaxSuffixComponents, CcnbParser::CCN_DTAG);
written += AppendNumber (start, interest.GetMaxSuffixComponents ());
written += AppendCloser (start);
}
if (interest.GetExclude().size() > 0)
{
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Exclude, CcnbParser::CCN_DTAG); // <Exclude>
written += AppendNameComponents (start, interest.GetExclude()); // <Component>...</Component>...
written += AppendCloser (start); // </Exclude>
}
if (interest.IsEnabledChildSelector())
{
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_ChildSelector, CcnbParser::CCN_DTAG);
written += AppendNumber (start, 1);
written += AppendCloser (start);
}
if (interest.IsEnabledAnswerOriginKind())
{
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_AnswerOriginKind, CcnbParser::CCN_DTAG);
written += AppendNumber (start, 1);
written += AppendCloser (start);
}
if (interest.GetScope() >= 0)
{
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Scope, CcnbParser::CCN_DTAG);
written += AppendNumber (start, interest.GetScope ());
written += AppendCloser (start);
}
if (!interest.GetInterestLifetime().IsZero())
{
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_InterestLifetime, CcnbParser::CCN_DTAG);
written += AppendTimestampBlob (start, interest.GetInterestLifetime());
written += AppendCloser (start);
}
if (interest.GetNonce()>0)
{
uint32_t nonce = interest.GetNonce();
written += AppendTaggedBlob (start, CcnbParser::CCN_DTAG_Nonce,
reinterpret_cast<const uint8_t*>(&nonce),
sizeof(nonce));
}
written += AppendCloser (start); // </Interest>
return written;
}
size_t
CcnxEncodingHelper::Serialize (Buffer::Iterator start, const CcnxContentObjectHeader &contentObject)
{
size_t written = 0;
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_ContentObject, CcnbParser::CCN_DTAG); // <ContentObject>
// fake signature
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Signature, CcnbParser::CCN_DTAG); // <Signature>
// Signature ::= DigestAlgorithm?
// Witness?
// SignatureBits
written += AppendTaggedBlob (start, CcnbParser::CCN_DTAG_SignatureBits, 0, 0); // <SignatureBits />
written += AppendCloser (start); // </Signature>
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Name, CcnbParser::CCN_DTAG); // <Name>
written += AppendNameComponents (start, contentObject.GetName()); // <Component>...</Component>...
written += AppendCloser (start); // </Name>
// fake signature
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_SignedInfo, CcnbParser::CCN_DTAG); // <SignedInfo>
// SignedInfo ::= PublisherPublicKeyDigest
// Timestamp
// Type?
// FreshnessSeconds?
// FinalBlockID?
// KeyLocator?
written += AppendTaggedBlob (start, CcnbParser::CCN_DTAG_PublisherPublicKeyDigest, 0, 0); // <PublisherPublicKeyDigest />
written += AppendCloser (start); // </SignedInfo>
written += AppendBlockHeader (start, CcnbParser::CCN_DTAG_Content, CcnbParser::CCN_DTAG); // <Content>
// there is no closing tag !!!
return written;
}
} // namespace ns3