1 files changed, 525 insertions, 0 deletions
diff --git a/lib/decoding/openbts/BitVector.cpp b/lib/decoding/openbts/BitVector.cpp
new file mode 100644
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--- /dev/null
+++ b/lib/decoding/openbts/BitVector.cpp
@@ -0,0 +1,525 @@
+/*
+ * Copyright 2008, 2009, 2014 Free Software Foundation, Inc.
+ * Copyright 2014 Range Networks, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * This use of this software may be subject to additional restrictions.
+ * See the LEGAL file in the main directory for details.
+ */
+
+#include "BitVector.h"
+#include <iostream>
+#include <stdio.h>
+#include <sstream>
+#include <string.h>
+//#include <Logger.h>
+
+using namespace std;
+
+
+
+BitVector::BitVector(const char *valString)
+{
+	// 1-30-2013 pat: I dont know what this was intended to do, but it did not create a normalized BitVector,
+	// and it could even fail if the accum overlows 8 bits.
+	//uint32_t accum = 0;
+	//for (size_t i=0; i<size(); i++) {
+	//	accum <<= 1;
+	//	if (valString[i]=='1') accum |= 0x01;
+	//	mStart[i] = accum;
+	//}
+	vInit(strlen(valString));
+	char *rp = begin();
+	for (const char *cp = valString; *cp; cp++, rp++) {
+		*rp = (*cp == '1');
+	}
+}
+
+
+uint64_t BitVector::peekField(size_t readIndex, unsigned length) const
+{
+	uint64_t accum = 0;
+	char *dp = mStart + readIndex;
+
+	for (unsigned i=0; i<length; i++) {
+		accum = (accum<<1) | ((*dp++) & 0x01);
+	}
+	return accum;
+}
+
+
+
+
+uint64_t BitVector::peekFieldReversed(size_t readIndex, unsigned length) const
+{
+	uint64_t accum = 0;
+	char *dp = mStart + readIndex + length - 1;
+	assert(dp<mEnd);
+	for (int i=(length-1); i>=0; i--) {
+		accum = (accum<<1) | ((*dp--) & 0x01);
+	}
+	return accum;
+}
+
+
+
+
+uint64_t BitVector::readField(size_t& readIndex, unsigned length) const
+{
+	const uint64_t retVal = peekField(readIndex,length);
+	readIndex += length;
+	return retVal;
+}
+
+
+uint64_t BitVector::readFieldReversed(size_t& readIndex, unsigned length) const
+{
+
+	const uint64_t retVal = peekFieldReversed(readIndex,length);
+	readIndex += length;
+	return retVal;
+
+}
+
+
+
+
+void BitVector::fillField(size_t writeIndex, uint64_t value, unsigned length)
+{
+	if (length != 0) {
+		char *dpBase = mStart + writeIndex;
+		char *dp = dpBase + length - 1;
+		assert(dp < mEnd);
+		while (dp>=dpBase) {
+			*dp-- = value & 0x01;
+			value >>= 1;
+		}
+	}
+}
+
+
+void BitVector::fillFieldReversed(size_t writeIndex, uint64_t value, unsigned length)
+{
+	if (length != 0) {
+		char *dp = mStart + writeIndex;
+		char *dpEnd = dp + length - 1;
+		assert(dpEnd < mEnd);
+		while (dp<=dpEnd) {
+			*dp++ = value & 0x01;
+			value >>= 1;
+		}
+	}
+}
+
+
+
+
+void BitVector::writeField(size_t& writeIndex, uint64_t value, unsigned length)
+{
+	if (length != 0) {
+		fillField(writeIndex,value,length);
+		writeIndex += length;
+	}
+}
+
+
+void BitVector::writeFieldReversed(size_t& writeIndex, uint64_t value, unsigned length)
+{
+	if (length != 0) {
+		fillFieldReversed(writeIndex,value,length);
+		writeIndex += length;
+	}
+}
+
+
+void BitVector::invert()
+{
+	for (size_t i=0; i<size(); i++) {
+		mStart[i] = ~mStart[i];
+	}
+}
+
+
+
+
+void BitVector::reverse8()
+{
+	assert(size()>=8);
+
+	char tmp0 = mStart[0];
+	mStart[0] = mStart[7];
+	mStart[7] = tmp0;
+
+	char tmp1 = mStart[1];
+	mStart[1] = mStart[6];
+	mStart[6] = tmp1;
+
+	char tmp2 = mStart[2];
+	mStart[2] = mStart[5];
+	mStart[5] = tmp2;
+
+	char tmp3 = mStart[3];
+	mStart[3] = mStart[4];
+	mStart[4] = tmp3;
+}
+
+
+
+void BitVector::LSB8MSB()
+{
+	if (size()<8) return;
+	size_t size8 = 8*(size()/8);
+	size_t iTop = size8 - 8;
+	for (size_t i=0; i<=iTop; i+=8) segment(i,8).reverse8();
+}
+
+
+
+uint64_t BitVector::syndrome(Generator& gen) const
+{
+	gen.clear();
+	const char *dp = mStart;
+	while (dp<mEnd) gen.syndromeShift(*dp++);
+	return gen.state();
+}
+
+
+uint64_t BitVector::parity(Generator& gen) const
+{
+	gen.clear();
+	const char *dp = mStart;
+	while (dp<mEnd) gen.encoderShift(*dp++);
+	return gen.state();
+}
+
+
+unsigned BitVector::sum() const
+{
+	unsigned sum = 0;
+	for (size_t i=0; i<size(); i++) sum += mStart[i] & 0x01;
+	return sum;
+}
+
+
+
+
+void BitVector::map(const unsigned *map, size_t mapSize, BitVector& dest) const
+{
+	for (unsigned i=0; i<mapSize; i++) {
+		dest.mStart[i] = mStart[map[i]];
+	}
+}
+
+
+
+
+void BitVector::unmap(const unsigned *map, size_t mapSize, BitVector& dest) const
+{
+	for (unsigned i=0; i<mapSize; i++) {
+		dest.mStart[map[i]] = mStart[i];
+	}
+}
+
+
+
+
+
+
+
+ostream& operator<<(ostream& os, const BitVector& hv)
+{
+	for (size_t i=0; i<hv.size(); i++) {
+		if (hv.bit(i)) os << '1';
+		else os << '0';
+	}
+	return os;
+}
+
+
+
+
+uint64_t Parity::syndrome(const BitVector& receivedCodeword)
+{
+	return receivedCodeword.syndrome(*this);
+}
+
+
+void Parity::writeParityWord(const BitVector& data, BitVector& parityTarget, bool invert)
+{
+	uint64_t pWord = data.parity(*this);
+	if (invert) pWord = ~pWord;
+	parityTarget.fillField(0,pWord,size());
+}
+
+
+
+
+
+
+
+
+
+SoftVector::SoftVector(const BitVector& source)
+{
+	resize(source.size());
+	for (size_t i=0; i<size(); i++) {
+		if (source.bit(i)) mStart[i]=1.0F;
+		else mStart[i]=0.0F;
+	}
+}
+
+
+BitVector SoftVector::sliced() const
+{
+	size_t sz = size();
+	BitVector newSig(sz);
+	for (size_t i=0; i<sz; i++) {
+		if (mStart[i]>0.5F) newSig[i]=1;
+		else newSig[i] = 0;
+	}
+	return newSig;
+}
+
+
+
+// (pat) Added 6-22-2012
+float SoftVector::getEnergy(float *plow) const
+{
+	const SoftVector &vec = *this;
+	int len = vec.size();
+	float avg = 0; float low = 1;
+	for (int i = 0; i < len; i++) {
+		float bit = vec[i];
+		float energy = 2*((bit < 0.5) ? (0.5-bit) : (bit-0.5));
+		if (energy < low) low = energy;
+		avg += energy/len;
+	}
+	if (plow) { *plow = low; }
+	return avg;
+}
+
+// (pat) Added 1-2014.  Compute SNR of a soft vector.  Very similar to above.
+// Since we dont really know what the expected signal values are, we will assume that the signal is 0 or 1
+// and return the SNR on that basis.
+// SNR is power(signal) / power(noise) where power can be calculated as (RMS(signal) / RMS(noise))**2 of the values.
+// Since RMS is square-rooted, ie RMS = sqrt(1/n * (x1**2 + x2**2 ...)), we just add up the squares.
+// To compute RMS of the signal we will remove any constant offset, so the signal values are either 0.5 or -0.5,
+// so the RMS of the signal is just 0.5**2 * len;  all we need to compute is the noise component.
+float SoftVector::getSNR() const
+{
+	float sumSquaresNoise = 0;
+	const SoftVector &vec = *this;
+	int len = vec.size();
+	if (len == 0) { return 0.0; }
+	for (int i = 0; i < len; i++) {
+		float bit = vec[i];
+		if (bit < 0.5) {
+			// Assume signal is 0.
+			sumSquaresNoise += (bit - 0.0) * (bit - 0.0);
+		} else {
+			// Assume signal is 1.
+			sumSquaresNoise += (bit - 1.0) * (bit - 1.0);
+		}
+	}
+	float sumSquaresSignal = 0.5 * 0.5 * len;
+	// I really want log10 of this to convert to dB, but log is expensive, and Harvind seems to like absolute SNR.
+	// Clamp max to 999; it shouldnt get up there but be sure.  This also avoids divide by zero.
+	if (sumSquaresNoise * 1000 < sumSquaresSignal) return 999;
+	return sumSquaresSignal / sumSquaresNoise;
+}
+
+
+
+ostream& operator<<(ostream& os, const SoftVector& sv)
+{
+	for (size_t i=0; i<sv.size(); i++) {
+		if (sv[i]<0.25) os << "0";
+		else if (sv[i]>0.75) os << "1";
+		else os << "-";
+	}
+	return os;
+}
+
+
+
+void BitVector::pack(unsigned char* targ) const
+{
+	// Assumes MSB-first packing.
+	unsigned bytes = size()/8;
+	for (unsigned i=0; i<bytes; i++) {
+		targ[i] = peekField(i*8,8);
+	}
+	unsigned whole = bytes*8;
+	unsigned rem = size() - whole;
+	if (rem==0) return;
+	targ[bytes] = peekField(whole,rem) << (8-rem);
+}
+
+void BitVector::pack2(unsigned char* targ) const
+{
+    unsigned int i;
+    unsigned char curbyte = 0;
+
+    for (i = 0; i < size(); i++)
+    {
+        uint8_t bitnum = 7 - (i % 8);
+        curbyte |= ((char)bit(i) << bitnum);
+        if(i % 8 == 7){
+            *targ++ = curbyte;
+            curbyte = 0;
+        }
+    }
+
+	// Assumes MSB-first packing.
+//	unsigned bytes = size()/8;
+//	for (unsigned i=0; i<bytes; i++) {
+//		targ[i] = peekField(i*8,8);
+//	}
+//	unsigned whole = bytes*8;
+//	unsigned rem = size() - whole;
+//	if (rem==0) return;
+//	targ[bytes] = peekField(whole,rem) << (8-rem);
+}
+
+
+
+string BitVector::packToString() const
+{
+	string result;
+	result.reserve((size()+7)/8);
+	// Tempting to call this->pack(result.c_str()) but technically c_str() is read-only.
+	unsigned bytes = size()/8;
+	for (unsigned i=0; i<bytes; i++) {
+		result.push_back(peekField(i*8,8));
+	}
+	unsigned whole = bytes*8;
+	unsigned rem = size() - whole;
+	if (rem==0) return result;
+	result.push_back(peekField(whole,rem) << (8-rem));
+	return result;
+}
+
+
+void BitVector::unpack(const unsigned char* src)
+{
+	// Assumes MSB-first packing.
+	unsigned bytes = size()/8;
+	for (unsigned i=0; i<bytes; i++) {
+		fillField(i*8,src[i],8);
+	}
+	unsigned whole = bytes*8;
+	unsigned rem = size() - whole;
+	if (rem==0) return;
+        fillField(whole,src[bytes] >> (8-rem),rem);
+}
+
+void BitVector::hex(ostream& os) const
+{
+	os << std::hex;
+	unsigned digits = size()/4;
+	size_t wp=0;
+	for (unsigned i=0; i<digits; i++) {
+		os << readField(wp,4);
+	}
+	os << std::dec;
+}
+
+std::string BitVector::hexstr() const
+{
+	std::ostringstream ss;
+	hex(ss);
+	return ss.str();
+}
+
+
+bool BitVector::unhex(const char* src)
+{
+	// Assumes MSB-first packing.
+	unsigned int val;
+	unsigned digits = size()/4;
+	for (unsigned i=0; i<digits; i++) {
+		if (sscanf(src+i, "%1x", &val) < 1) {
+			return false;
+		}
+		fillField(i*4,val,4);
+	}
+	unsigned whole = digits*4;
+	unsigned rem = size() - whole;
+	if (rem>0) {
+		if (sscanf(src+digits, "%1x", &val) < 1) {
+			return false;
+		}
+		fillField(whole,val,rem);
+	}
+	return true;
+}
+
+bool BitVector::operator==(const BitVector &other) const
+{
+	unsigned l = size();
+	return l == other.size() && 0==memcmp(begin(),other.begin(),l);
+}
+
+void BitVector::copyPunctured(BitVector &dst, const unsigned *puncture, const size_t plth)
+{
+	assert(size() - plth == dst.size());
+	char *srcp = mStart;
+	char *dstp = dst.mStart;
+	const unsigned *pend = puncture + plth;
+	while (srcp < mEnd) {
+		if (puncture < pend) {
+			int n = (*puncture++) - (srcp - mStart);
+			assert(n >= 0);
+			for (int i = 0; i < n; i++) {
+				assert(srcp < mEnd && dstp < dst.mEnd);
+				*dstp++ = *srcp++;
+			}
+			srcp++;
+		} else {
+			while (srcp < mEnd) {
+				assert(dstp < dst.mEnd);
+				*dstp++ = *srcp++;
+			}
+		}
+	}
+	assert(dstp == dst.mEnd && puncture == pend);
+}
+
+void SoftVector::copyUnPunctured(SoftVector &dst, const unsigned *puncture, const size_t plth)
+{
+	assert(size() + plth == dst.size());
+	float *srcp = mStart;
+	float *dstp = dst.mStart;
+	const unsigned *pend = puncture + plth;
+	while (dstp < dst.mEnd) {
+		if (puncture < pend) {
+			int n = (*puncture++) - (dstp - dst.mStart);
+			assert(n >= 0);
+			for (int i = 0; i < n; i++) {
+				assert(srcp < mEnd && dstp < dst.mEnd);
+				*dstp++ = *srcp++;
+			}
+			*dstp++ = 0.5;
+		} else {
+			while (srcp < mEnd) {
+				assert(dstp < dst.mEnd);
+				*dstp++ = *srcp++;
+			}
+		}
+	}
+	assert(dstp == dst.mEnd && puncture == pend);
+}
+
+// vim: ts=4 sw=4