Add arduino-rx + update ggwave-mod

examples/ggwave-mod/src/resampler.h

@@ -0,0 +1,49 @@
+#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;
+};