mirror of
https://github.com/RangeNetworks/openbts.git
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85 lines
2.5 KiB
C++
85 lines
2.5 KiB
C++
/*
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* Copyright 2011, 2014 Range Networks, Inc.
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*
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* This software is distributed under multiple licenses;
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* see the COPYING file in the main directory for licensing
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* information for this specific distribution.
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*
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* This use of this software may be subject to additional restrictions.
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* See the LEGAL file in the main directory for details.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#define LOG_GROUP LogGroup::GPRS // Can set Log.Level.GPRS for debugging
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#include "GPRSRLC.h"
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#include "GSMCommon.h"
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namespace GPRS {
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int deltaBSN(int bsn1,int bsn2)
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{
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static const int halfModulus = RLCBSN_t::BSNPeriodicity/2;
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int delta = bsn1 - bsn2;
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if (delta>=halfModulus) delta -= RLCBSN_t::BSNPeriodicity;
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else if (delta<-halfModulus) delta += RLCBSN_t::BSNPeriodicity;
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return delta;
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}
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// Based on GSM::FNDelta
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// We assume the values are within a half periodicity of each other.
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int RLCBSN_t::BSNdelta(RLCBSN_t v2)
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{
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RLCBSN_t v1 = *this;
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//int delta = v1.mValue - v2.mValue;
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//if (delta>=halfModulus) delta -= BSNPeriodicity;
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//else if (delta<-halfModulus) delta += BSNPeriodicity;
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//return RLCBSN_t(delta);
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return RLCBSN_t(deltaBSN(v1.mValue,v2.mValue));
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}
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// Return 1 if v1 > v2; return -1 if v1 < v2, using modulo BSNPeriodicity.
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int RLCBSN_t::BSNcompare(RLCBSN_t v2)
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{
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int delta = BSNdelta(v2);
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if (delta>0) return 1;
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if (delta<0) return -1;
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return 0;
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}
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// (pat) Return the block radio number for a frame number.
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RLCBSN_t FrameNumber2BSN(int fn)
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{
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// The RLC blocks use a 52-multiframe, but each 13-multiframe is identical:
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// the first 12 frames are 3 RLC blocks, and the last frame is for timing or idle.
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int mfn = (fn / 13); // how many 13-multiframes
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int rem = (fn - (mfn*13)); // how many blocks within the last multiframe.
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RLCBSN_t result = mfn * 3 + ((rem==12) ? 2 : (rem/4));
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result.normalize();
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return result;
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}
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// Return the Block Sequence Number for a frame number.
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// There are 12 radio blocks per 52 frames,
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int BSN2FrameNumber(RLCBSN_t absn) // absolute block sequence number.
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{
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// One extra frame is inserted after every 3 radio blocks,
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// so 3 radio blocks take 13 frames.
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int bsn = absn; // Convert to int so we do math on int, not RLCBSN_t
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int result = ((int)bsn / 3) * 13 + ((int)bsn % 3) * 4;
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assert(result >= 0 && (unsigned) result <= GSM::gHyperframe);
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return result;
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}
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std::ostream& operator<<(std::ostream& os, const RLCDir::type &dir)
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{
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os << RLCDir::name(dir);
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return os;
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}
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};
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