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Diffstat (limited to 'src/lib/decoder/openbtsstuff/BitVector.h')
| -rw-r--r-- | src/lib/decoder/openbtsstuff/BitVector.h | 427 |
1 files changed, 0 insertions, 427 deletions
diff --git a/src/lib/decoder/openbtsstuff/BitVector.h b/src/lib/decoder/openbtsstuff/BitVector.h deleted file mode 100644 index 3019c2c..0000000 --- a/src/lib/decoder/openbtsstuff/BitVector.h +++ /dev/null @@ -1,427 +0,0 @@ -/* -* Copyright 2008 Free Software Foundation, Inc. -* -* This software is distributed under the terms of the GNU Public License. -* See the COPYING file in the main directory for details. - - This program is free software: you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation, either version 3 of the License, or - (at your option) any later version. - - 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, see <http://www.gnu.org/licenses/>. - -*/ - - -#ifndef FECVECTORS_H -#define FECVECTORS_H - -#include "Vector.h" -#include <stdint.h> - - -class BitVector; -class SoftVector; - - - -/** Shift-register (LFSR) generator. */ -class Generator { - - private: - - uint64_t mCoeff; ///< polynomial coefficients. LSB is zero exponent. - uint64_t mState; ///< shift register state. LSB is most recent. - uint64_t mMask; ///< mask for reading state - unsigned mLen; ///< number of bits used in shift register - unsigned mLen_1; ///< mLen - 1 - - public: - - Generator(uint64_t wCoeff, unsigned wLen) - :mCoeff(wCoeff),mState(0), - mMask((1ULL<<wLen)-1), - mLen(wLen),mLen_1(wLen-1) - { assert(wLen<64); } - - void clear() { mState=0; } - - /**@name Accessors */ - //@{ - uint64_t state() const { return mState & mMask; } - unsigned size() const { return mLen; } - //@} - - /** - Calculate one bit of a syndrome. - This is in the .h for inlining. - */ - void syndromeShift(unsigned inBit) - { - const unsigned fb = (mState>>(mLen_1)) & 0x01; - mState = (mState<<1) ^ (inBit & 0x01); - if (fb) mState ^= mCoeff; - } - - /** - Update the generator state by one cycle. - This is in the .h for inlining. - */ - void encoderShift(unsigned inBit) - { - const unsigned fb = ((mState>>(mLen_1)) ^ inBit) & 0x01; - mState <<= 1; - if (fb) mState ^= mCoeff; - } - - -}; - - - - -/** Parity (CRC-type) generator and checker based on a Generator. */ -class Parity : public Generator { - - protected: - - unsigned mCodewordSize; - - public: - - Parity(uint64_t wCoefficients, unsigned wParitySize, unsigned wCodewordSize) - :Generator(wCoefficients, wParitySize), - mCodewordSize(wCodewordSize) - { } - - /** Compute the parity word and write it into the target segment. */ - void writeParityWord(const BitVector& data, BitVector& parityWordTarget, bool invert=true); - - /** Compute the syndrome of a received sequence. */ - uint64_t syndrome(const BitVector& receivedCodeword); -}; - - - - -/** - Class to represent convolutional coders/decoders of rate 1/2, memory length 4. - This is the "workhorse" coder for most GSM channels. -*/ -class ViterbiR2O4 { - - private: - /**name Lots of precomputed elements so the compiler can optimize like hell. */ - //@{ - /**@name Core values. */ - //@{ - static const unsigned mIRate = 2; ///< reciprocal of rate - static const unsigned mOrder = 4; ///< memory length of generators - //@} - /**@name Derived values. */ - //@{ - static const unsigned mIStates = 0x01 << mOrder; ///< number of states, number of survivors - static const uint32_t mSMask = mIStates-1; ///< survivor mask - static const uint32_t mCMask = (mSMask<<1) | 0x01; ///< candidate mask - static const uint32_t mOMask = (0x01<<mIRate)-1; ///< ouput mask, all iRate low bits set - static const unsigned mNumCands = mIStates*2; ///< number of candidates to generate during branching - static const unsigned mDeferral = 6*mOrder; ///< deferral to be used - //@} - //@} - - /** Precomputed tables. */ - //@{ - uint32_t mCoeffs[mIRate]; ///< polynomial for each generator - uint32_t mStateTable[mIRate][2*mIStates]; ///< precomputed generator output tables - uint32_t mGeneratorTable[2*mIStates]; ///< precomputed coder output table - //@} - - public: - - /** - A candidate sequence in a Viterbi decoder. - The 32-bit state register can support a deferral of 6 with a 4th-order coder. - */ - typedef struct candStruct { - uint32_t iState; ///< encoder input associated with this candidate - uint32_t oState; ///< encoder output associated with this candidate - float cost; ///< cost (metric value), float to support soft inputs - } vCand; - - /** Clear a structure. */ - void clear(vCand& v) - { - v.iState=0; - v.oState=0; - v.cost=0; - } - - - private: - - /**@name Survivors and candidates. */ - //@{ - vCand mSurvivors[mIStates]; ///< current survivor pool - vCand mCandidates[2*mIStates]; ///< current candidate pool - //@} - - public: - - unsigned iRate() const { return mIRate; } - uint32_t cMask() const { return mCMask; } - uint32_t stateTable(unsigned g, unsigned i) const { return mStateTable[g][i]; } - unsigned deferral() const { return mDeferral; } - - - ViterbiR2O4(); - - /** Set all cost metrics to zero. */ - void initializeStates(); - - /** - Full cycle of the Viterbi algorithm: branch, metrics, prune, select. - @return reference to minimum-cost candidate. - */ - const vCand& step(uint32_t inSample, const float *probs, const float *iprobs); - - private: - - /** Branch survivors into new candidates. */ - void branchCandidates(); - - /** Compute cost metrics for soft-inputs. */ - void getSoftCostMetrics(uint32_t inSample, const float *probs, const float *iprobs); - - /** Select survivors from the candidate set. */ - void pruneCandidates(); - - /** Find the minimum cost survivor. */ - const vCand& minCost() const; - - /** - Precompute the state tables. - @param g Generator index 0..((1/rate)-1) - */ - void computeStateTables(unsigned g); - - /** - Precompute the generator outputs. - mCoeffs must be defined first. - */ - void computeGeneratorTable(); - -}; - - - - -class BitVector : public Vector<char> { - - - public: - - /**@name Constructors. */ - //@{ - - /**@name Casts of Vector constructors. */ - //@{ - BitVector(char* wData, char* wStart, char* wEnd) - :Vector<char>(wData,wStart,wEnd) - { } - BitVector(size_t len=0):Vector<char>(len) {} - BitVector(const Vector<char>& source):Vector<char>(source) {} - BitVector(Vector<char>& source):Vector<char>(source) {} - BitVector(const Vector<char>& source1, const Vector<char> source2):Vector<char>(source1,source2) {} - //@} - - /** Construct from a string of "0" and "1". */ - BitVector(const char* valString); - //@} - - /** Index a single bit. */ - bool bit(size_t index) const - { - // We put this code in .h for fast inlining. - const char *dp = mStart+index; - assert(dp<mEnd); - return (*dp) & 0x01; - } - - /**@name Casts and overrides of Vector operators. */ - //@{ - BitVector segment(size_t start, size_t span) - { - char* wStart = mStart + start; - char* wEnd = wStart + span; - assert(wEnd<=mEnd); - return BitVector(NULL,wStart,wEnd); - } - - BitVector alias() - { return segment(0,size()); } - - const BitVector segment(size_t start, size_t span) const - { return (BitVector)(Vector<char>::segment(start,span)); } - - BitVector head(size_t span) { return segment(0,span); } - const BitVector head(size_t span) const { return segment(0,span); } - BitVector tail(size_t start) { return segment(start,size()-start); } - const BitVector tail(size_t start) const { return segment(start,size()-start); } - //@} - - - void zero() { fill(0); } - - /**@name FEC operations. */ - //@{ - /** Calculate the syndrome of the vector with the given Generator. */ - uint64_t syndrome(Generator& gen) const; - /** Calculate the parity word for the vector with the given Generator. */ - uint64_t parity(Generator& gen) const; - /** Encode the signal with the GSM rate 1/2 convolutional encoder. */ - void encode(const ViterbiR2O4& encoder, BitVector& target); - //@} - - - /** Invert 0<->1. */ - void invert(); - - /**@name Byte-wise operations. */ - //@{ - /** Reverse an 8-bit vector. */ - void reverse8(); - /** Reverse groups of 8 within the vector (byte reversal). */ - void LSB8MSB(); - //@} - - /**@name Serialization and deserialization. */ - //@{ - uint64_t peekField(size_t readIndex, unsigned length) const; - uint64_t readField(size_t& readIndex, unsigned length) const; - void fillField(size_t writeIndex, uint64_t value, unsigned length); - void writeField(size_t& writeIndex, uint64_t value, unsigned length); - //@} - - /** Sum of bits. */ - unsigned sum() const; - - /** Reorder bits, dest[i] = this[map[i]]. */ - void map(const unsigned *map, size_t mapSize, BitVector& dest) const; - - /** Reorder bits, dest[map[i]] = this[i]. */ - void unmap(const unsigned *map, size_t mapSize, BitVector& dest) const; - - /** Pack into a char array. */ - void pack(unsigned char*) const; - - /** Unopack from a char array. */ - void unpack(const unsigned char*); - -}; - - - -std::ostream& operator<<(std::ostream&, const BitVector&); - - - - - - -/** - The SoftVector class is used to represent a soft-decision signal. - Values 0..1 represent probabilities that a bit is "true". - */ -class SoftVector: public Vector<float> { - - public: - - /** Build a SoftVector of a given length. */ - SoftVector(size_t wSize=0):Vector<float>(wSize) {} - - /** Construct a SoftVector from a C string of "0", "1", and "X". */ - SoftVector(const char* valString); - - /** Construct a SoftVector from a BitVector. */ - SoftVector(const BitVector& source); - - /** - Wrap a SoftVector around a block of floats. - The block will be delete[]ed upon desctuction. - */ - SoftVector(float *wData, unsigned length) - :Vector<float>(wData,length) - {} - - SoftVector(float* wData, float* wStart, float* wEnd) - :Vector<float>(wData,wStart,wEnd) - { } - - /** - Casting from a Vector<float>. - Note that this is NOT pass-by-reference. - */ - SoftVector(Vector<float> source) - :Vector<float>(source) - {} - - - /**@name Casts and overrides of Vector operators. */ - //@{ - SoftVector segment(size_t start, size_t span) - { - float* wStart = mStart + start; - float* wEnd = wStart + span; - assert(wEnd<=mEnd); - return SoftVector(NULL,wStart,wEnd); - } - - SoftVector alias() - { return segment(0,size()); } - - const SoftVector segment(size_t start, size_t span) const - { return (SoftVector)(Vector<float>::segment(start,span)); } - - SoftVector head(size_t span) { return segment(0,span); } - const SoftVector head(size_t span) const { return segment(0,span); } - SoftVector tail(size_t start) { return segment(start,size()-start); } - const SoftVector tail(size_t start) const { return segment(start,size()-start); } - //@} - - /** Decode soft symbols with the GSM rate-1/2 Viterbi decoder. */ - void decode(ViterbiR2O4 &decoder, BitVector& target) const; - - /** Fill with "unknown" values. */ - void unknown() { fill(0.5F); } - - /** Return a hard bit value from a given index by slicing. */ - bool bit(size_t index) const - { - const float *dp = mStart+index; - assert(dp<mEnd); - return (*dp)>0.5F; - } - - /** Slice the whole signal into bits. */ - BitVector sliced() const; - -}; - - - -std::ostream& operator<<(std::ostream&, const SoftVector&); - - - - - - -#endif -// vim: ts=4 sw=4 |