wip : pimpled Tx and moved resampler inside GGWave

bindings/python/setup-tmpl.py

@@ -38,7 +38,7 @@ setup(
     keywords = "data-over-sound fsk ecc serverless pairing qrcode ultrasound",
     # Build instructions
     ext_modules = [Extension("ggwave",
-                             [ggwave_module_src, "ggwave/src/ggwave.cpp", "ggwave/src/resampler.cpp"],
+                             [ggwave_module_src, "ggwave/src/ggwave.cpp"],
                              include_dirs=["ggwave/include", "ggwave/include/ggwave"],
                              depends=["ggwave/include/ggwave/ggwave.h"],
                              language="c++",

bindings/python/setup.py

@@ -38,7 +38,7 @@ setup(
     keywords = "data-over-sound fsk ecc serverless pairing qrcode ultrasound",
     # Build instructions
     ext_modules = [Extension("ggwave",
-                             [ggwave_module_src, "ggwave/src/ggwave.cpp", "ggwave/src/resampler.cpp"],
+                             [ggwave_module_src, "ggwave/src/ggwave.cpp"],
                              include_dirs=["ggwave/include", "ggwave/include/ggwave"],
                              depends=["ggwave/include/ggwave/ggwave.h"],
                              language="c++",

examples/arduino-rx/CMakeLists.txt

@@ -3,8 +3,6 @@
 
 configure_file(${CMAKE_SOURCE_DIR}/include/ggwave/ggwave.h   ${CMAKE_CURRENT_SOURCE_DIR}/ggwave/ggwave.h COPYONLY)
 configure_file(${CMAKE_SOURCE_DIR}/src/ggwave.cpp            ${CMAKE_CURRENT_SOURCE_DIR}/ggwave.cpp COPYONLY)
-configure_file(${CMAKE_SOURCE_DIR}/src/resampler.h           ${CMAKE_CURRENT_SOURCE_DIR}/resampler.h COPYONLY)
-configure_file(${CMAKE_SOURCE_DIR}/src/resampler.cpp         ${CMAKE_CURRENT_SOURCE_DIR}/resampler.cpp COPYONLY)
 configure_file(${CMAKE_SOURCE_DIR}/src/reed-solomon/gf.hpp   ${CMAKE_CURRENT_SOURCE_DIR}/reed-solomon/gf.hpp COPYONLY)
 configure_file(${CMAKE_SOURCE_DIR}/src/reed-solomon/rs.hpp   ${CMAKE_CURRENT_SOURCE_DIR}/reed-solomon/rs.hpp COPYONLY)
 configure_file(${CMAKE_SOURCE_DIR}/src/reed-solomon/poly.hpp ${CMAKE_CURRENT_SOURCE_DIR}/reed-solomon/poly.hpp COPYONLY)

include/ggwave/ggwave.h

@@ -450,7 +450,7 @@ public:
     //
     //   Call this method after calling encode() to get a list of the tones participating in the generated waveform
     //
-    const WaveformTones & getWaveformTones() { return m_waveformTones; }
+    const WaveformTones & getWaveformTones() const;
 
     bool takeTxAmplitudeI16(AmplitudeDataI16 & dst);
 
@@ -487,6 +487,53 @@ public:
     //
     static bool computeFFTR(const float * src, float * dst, int N, float d);
 
+    // resample audio waveforms from one sample rate to another using
+    // sinc interpolation
+    class Resampler {
+    public:
+        // this controls the number of neighboring samples
+        // which are used to interpolate the new samples. The
+        // processing time is linearly related to this width
+        static const int kWidth = 64;
+
+        Resampler();
+
+        void reset();
+
+        int nSamplesTotal() const { return m_state.nSamplesTotal; }
+
+        int resample(
+                float factor,
+                int nSamples,
+                const float * samplesInp,
+                float * samplesOut);
+
+    private:
+        float getData(int j) const;
+        void newData(float data);
+        void makeSinc();
+        double sinc(double x) const;
+
+        static const int kDelaySize = 140;
+
+        // this defines how finely the sinc function is sampled for storage in the table
+        static const int kSamplesPerZeroCrossing = 32;
+
+        std::vector<float> m_sincTable;
+        std::vector<float> m_delayBuffer;
+        std::vector<float> m_edgeSamples;
+        std::vector<float> m_samplesInp;
+
+        struct State {
+            int nSamplesTotal = 0;
+            int timeInt = 0;
+            int timeLast = 0;
+            double timeNow = 0.0;
+        };
+
+        State m_state;
+    };
+
 private:
     void decode_fixed();
     void decode_variable();
@@ -530,25 +577,14 @@ private:
     // common
     TxRxData m_dataEncoded;
 
-    // Tx
-    bool m_hasNewTxData;
-    float m_sendVolume;
-
-    int m_txDataLength;
-    TxRxData m_txData;
-    TxProtocol m_txProtocol;
-
-    AmplitudeData m_outputBlock;
-    AmplitudeData m_outputBlockResampled;
-    TxRxData m_outputBlockTmp;
-    AmplitudeDataI16 m_outputBlockI16;
-    AmplitudeDataI16 m_txAmplitudeDataI16;
-    WaveformTones m_waveformTones;
-
     // Impl
-    // todo : move all members inside Impl
+    struct Rx;
-    struct Impl;
+    std::unique_ptr<Rx> m_rx;
-    std::unique_ptr<Impl> m_impl;
+
+    struct Tx;
+    std::unique_ptr<Tx> m_tx;
+
+    std::unique_ptr<Resampler> m_resampler;
 };
 
 #endif

src/CMakeLists.txt

@@ -4,7 +4,6 @@ set(TARGET ggwave)
 
 add_library(${TARGET}
     ggwave.cpp
-    resampler.cpp
     )
 
 target_include_directories(${TARGET} PUBLIC

src/resampler.cpp

@@ -1,161 +0,0 @@
-#include "resampler.h"
-
-#include <cassert>
-#include <cmath>
-#include <cstdio>
-
-#ifndef M_PI
-#define M_PI 3.14159265358979323846
-#endif
-
-namespace {
-double linear_interp(double first_number, double second_number, double fraction) {
-    return (first_number + ((second_number - first_number)*fraction));
-}
-}
-
-Resampler::Resampler() :
-    m_sincTable(kWidth*kSamplesPerZeroCrossing),
-    m_delayBuffer(3*kWidth),
-    m_edgeSamples(kWidth),
-    m_samplesInp(2048) {
-    make_sinc();
-    reset();
-}
-
-void Resampler::reset() {
-    m_state = {};
-    std::fill(m_edgeSamples.begin(), m_edgeSamples.end(), 0.0f);
-    std::fill(m_delayBuffer.begin(), m_delayBuffer.end(), 0.0f);
-    std::fill(m_samplesInp.begin(), m_samplesInp.end(), 0.0f);
-}
-
-int Resampler::resample(
-        float factor,
-        int nSamples,
-        const float * samplesInp,
-        float * samplesOut) {
-    int idxInp = -1;
-    int idxOut = 0;
-    int notDone = 1;
-    float data_in = 0.0f;
-    float data_out = 0.0f;
-    double one_over_factor = 1.0;
-
-    auto stateSave = m_state;
-
-    m_state.nSamplesTotal += nSamples;
-
-    if (samplesOut) {
-        assert(nSamples > kWidth);
-        if ((int) m_samplesInp.size() < nSamples + kWidth) {
-            m_samplesInp.resize(nSamples + kWidth);
-        }
-        for (int i = 0; i < kWidth; ++i) {
-            m_samplesInp[i] = m_edgeSamples[i];
-            m_edgeSamples[i] = samplesInp[nSamples - kWidth + i];
-        }
-        for (int i = 0; i < nSamples; ++i) {
-            m_samplesInp[i + kWidth] = samplesInp[i];
-        }
-        samplesInp = m_samplesInp.data();
-    }
-
-    while (notDone) {
-        while (m_state.timeLast < m_state.timeInt) {
-            if (++idxInp >= nSamples) {
-                notDone = 0;
-                break;
-            } else {
-                data_in = samplesInp[idxInp];
-            }
-            //printf("xxxx idxInp = %d\n", idxInp);
-            if (samplesOut) new_data(data_in);
-            m_state.timeLast += 1;
-        }
-
-        if (notDone == false) break;
-
-        double temp1 = 0.0;
-        int left_limit = m_state.timeNow - kWidth + 1; /* leftmost neighboring sample used for interp.*/
-        int right_limit = m_state.timeNow + kWidth;    /* rightmost leftmost neighboring sample used for interp.*/
-        if (left_limit < 0) left_limit = 0;
-        if (right_limit > m_state.nSamplesTotal + kWidth) right_limit = m_state.nSamplesTotal + kWidth;
-        if (factor < 1.0) {
-            for (int j = left_limit; j < right_limit; j++) {
-                temp1 += gimme_data(j - m_state.timeInt)*sinc(m_state.timeNow - (double) j);
-            }
-            data_out = temp1;
-        }
-        else {
-            one_over_factor = 1.0 / factor;
-            for (int j = left_limit; j < right_limit; j++) {
-                temp1 += gimme_data(j - m_state.timeInt)*one_over_factor*sinc(one_over_factor*(m_state.timeNow - (double) j));
-            }
-            data_out = temp1;
-        }
-
-        if (samplesOut) {
-            //printf("inp = %d, l = %d, r = %d, n = %d, a = %d, b = %d\n", idxInp, left_limit, right_limit, m_state.nSamplesTotal, left_limit - m_state.timeInt, right_limit - m_state.timeInt - 1);
-            samplesOut[idxOut] = data_out;
-        }
-        ++idxOut;
-
-        m_state.timeNow += factor;
-        m_state.timeLast = m_state.timeInt;
-        m_state.timeInt = m_state.timeNow;
-        while (m_state.timeLast < m_state.timeInt) {
-            if (++idxInp >= nSamples) {
-                notDone = 0;
-                break;
-            } else {
-                data_in = samplesInp[idxInp];
-            }
-            if (samplesOut) new_data(data_in);
-            m_state.timeLast += 1;
-        }
-        //printf("last idxInp = %d, nSamples = %d\n", idxInp, nSamples);
-    }
-
-    if (samplesOut == nullptr) {
-        m_state = stateSave;
-    }
-
-    return idxOut;
-}
-
-float Resampler::gimme_data(int j) const {
-    return m_delayBuffer[(int) j + kWidth];
-}
-
-void Resampler::new_data(float data) {
-    for (int i = 0; i < kDelaySize - 5; i++) {
-        m_delayBuffer[i] = m_delayBuffer[i + 1];
-    }
-    m_delayBuffer[kDelaySize - 5] = data;
-}
-
-void Resampler::make_sinc() {
-    double temp, win_freq, win;
-    win_freq = M_PI/kWidth/kSamplesPerZeroCrossing;
-    m_sincTable[0] = 1.0;
-    for (int i = 1; i < kWidth*kSamplesPerZeroCrossing; i++) {
-        temp = (double) i*M_PI/kSamplesPerZeroCrossing;
-        m_sincTable[i] = sin(temp)/temp;
-        win = 0.5 + 0.5*cos(win_freq*i);
-        m_sincTable[i] *= win;
-    }
-}
-
-double Resampler::sinc(double x) const {
-    int low;
-    double temp, delta;
-    if (fabs(x) >= kWidth - 1) {
-        return 0.0;
-    } else {
-        temp = fabs(x)*(double) kSamplesPerZeroCrossing;
-        low = temp;          /* these are interpolation steps */
-        delta = temp - low;  /* and can be ommited if desired */
-        return linear_interp(m_sincTable[low], m_sincTable[low + 1], delta);
-    }
-}

src/resampler.h

@@ -1,49 +0,0 @@
-#pragma once
-
-#include <vector>
-#include <cstdint>
-
-class Resampler {
-public:
-    // this controls the number of neighboring samples
-    // which are used to interpolate the new samples. The
-    // processing time is linearly related to this width
-    static const int kWidth = 64;
-
-    Resampler();
-
-    void reset();
-
-    int nSamplesTotal() const { return m_state.nSamplesTotal; }
-
-    int resample(
-            float factor,
-            int nSamples,
-            const float * samplesInp,
-            float * samplesOut);
-
-private:
-    float gimme_data(int j) const;
-    void new_data(float data);
-    void make_sinc();
-    double sinc(double x) const;
-
-    static const int kDelaySize = 140;
-
-    // this defines how finely the sinc function is sampled for storage in the table
-    static const int kSamplesPerZeroCrossing = 32;
-
-    std::vector<float> m_sincTable;
-    std::vector<float> m_delayBuffer;
-    std::vector<float> m_edgeSamples;
-    std::vector<float> m_samplesInp;
-
-    struct State {
-        int nSamplesTotal = 0;
-        int timeInt = 0;
-        int timeLast = 0;
-        double timeNow = 0.0;
-    };
-
-    State m_state;
-};