Minor changes; more comments

debug.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <stdio.h>
+
+
+#define LOG_INFO    0
+#define LOG_WARN    1
+#define LOG_ERROR   2
+#define LOG_FATAL   3
+
+
+#define LOG(level, ...)     if (level >= LOG_LEVEL) printf(__VA_ARGS__)

gen_ft8.cpp

@@ -10,14 +10,18 @@
 #include "encode_91.h"
 
 
-void synth_fsk(const uint8_t *symbols, int nSymbols, float f0, float spacing, float symbol_rate, float signal_rate, float *signal) {
+// Convert a sequence of symbols (tones) into a sinewave of continuous phase (FSK).
+// Symbol 0 gets encoded as a sine of frequency f0, the others are spaced in incresing
+// fashion.
+void synth_fsk(const uint8_t *symbols, int num_symbols, float f0, float spacing, 
+                float symbol_rate, float signal_rate, float *signal) {
     float phase = 0;
     float dt = 1/signal_rate;
     float dt_sym = 1/symbol_rate;
     float t = 0;
     int j = 0;
     int i = 0;
-    while (j < nSymbols) {
+    while (j < num_symbols) {
         float f = f0 + symbols[j] * spacing;
         phase += 2 * M_PI * f / signal_rate;
         signal[i] = sin(phase);
@@ -31,7 +35,7 @@ void synth_fsk(const uint8_t *symbols, int nSymbols, float f0, float spacing, fl
     }
 }
 
-
+// Save signal in floating point format (-1 .. +1) as a WAVE file using 16-bit signed integers.
 void save_wav(const float *signal, int num_samples, int sample_rate, const char *path) {
     FILE *f = fopen(path, "wb");
     char subChunk1ID[4] = {'f', 'm', 't', ' '};

test.cpp

@@ -3,29 +3,17 @@
 #include <cstdio>
 #include <cmath>
 
-#include <string>
-#include <vector>
-
 #include "text.h"
-
 #include "pack.h"
+#include "pack_77.h"
 #include "encode.h"
-
+#include "encode_91.h"
 #include "unpack.h"
 
-#include "pack_77.h"
+#include "debug.h"
-#include "encode_91.h"
-
 
 #define LOG_LEVEL   LOG_INFO
 
-#define LOG_INFO    0
-#define LOG_WARN    1
-#define LOG_ERROR   2
-#define LOG_FATAL   3
-
-#define LOG(level, ...)     if (level >= LOG_LEVEL) printf(__VA_ARGS__)
-
 
 void convert_8bit_to_6bit(uint8_t *dst, const uint8_t *src, int nBits) {
     // Zero-fill the destination array as we will only be setting bits later
@@ -53,28 +41,6 @@ void convert_8bit_to_6bit(uint8_t *dst, const uint8_t *src, int nBits) {
     }
 }
 
-class TestCase {
-public:
-    TestCase(const std::string &name) : _name(name) {
-        //_all_cases.push_back(this);
-    }
-
-    virtual bool run(const std::string &params) = 0;
-private:
-    std::string     _name;
-    //static std::vector<TestCase *> _all_cases;
-};
-
-//std::vector<TestCase *> TestCase::_all_cases;
-
-class TestCase1 : public TestCase {
-public:
-    TestCase1() : TestCase("Test Case 1") {}
-    bool run(const std::string &params) override {
-        return true;
-    }
-};
-
 
 bool test1() {
     //const char *msg = "CQ DL7ACA JO40"; // 62, 32, 32, 49, 37, 27, 59, 2, 30, 19, 49, 16
@@ -116,16 +82,16 @@ void test2() {
     encode174(test_in, test_out);
 
     for (int j = 0; j < 22; ++j) {
-        printf("%02x ", test_out[j]);
+        LOG(LOG_INFO, "%02x ", test_out[j]);
     }
-    printf("\n");
+    LOG(LOG_INFO, "\n");
 }
 
 
 void test3() {
     uint8_t test_in2[10] = { 0x11, 0x00, 0x00, 0x00, 0x00, 0x0E, 0x10, 0x04, 0x01, 0x00 };
     uint16_t crc1 = ft8_crc(test_in2, 76);  // Calculate CRC of 76 bits only
-    printf("CRC: %04x\n", crc1);            // should be 0x0708
+    LOG(LOG_INFO, "CRC: %04x\n", crc1);            // should be 0x0708
 }
 
 

unpack.cpp

@@ -41,55 +41,66 @@ void unpackcall(uint32_t nc, char *callsign) {
 
 
 // extract maidenhead locator
-void unpackgrid(uint32_t ng, char *grid) {
+void unpackgrid(uint16_t ng, char *grid) {
-    // // start of special grid locators for sig strength &c.
+    // start of special grid locators for sig strength &c.
-    // NGBASE = 180*180
+    constexpr uint16_t NGBASE = 180*180;
 
-    // if ng == NGBASE+1:
+    if (ng == NGBASE + 1) {
-    //     return "    "
+        grid[0] = 0;
+        return;
+    }
     // if ng >= NGBASE+1 and ng < NGBASE+31:
     //     return " -%02d" % (ng - (NGBASE+1)) // sig str, -01 to -30 DB
     // if ng >= NGBASE+31 and ng < NGBASE+62:
     //     return "R-%02d" % (ng - (NGBASE+31))
-    // if ng == NGBASE+62:
+    if (ng == NGBASE + 62) {
-    //     return "RO  "
+        strcpy(grid, "RO");
-    // if ng == NGBASE+63:
+        return;
-    //     return "RRR "
+    }
-    // if ng == NGBASE+64:
+    if (ng == NGBASE + 63) {
-    //     return "73  "
+        strcpy(grid, "RRR");
+        return;
+    }
+    if (ng == NGBASE + 64) {
+        strcpy(grid, "73");
+        return;        
+    }
 
-    // lat = (ng % 180) - 90
+    int16_t lat = (int16_t)(ng % 180) - 90;
-    // ng = int(ng / 180)
+    int16_t lng = ((int16_t)(ng / 180) * 2) - 180;
-    // lng = (ng * 2) - 180
 
-    // g = "%c%c%c%c" % (ord('A') + int((179-lng)/20),
+    grid[0] = 'A' + ((179 - lng) / 20);
-    //                     ord('A') + int((lat+90)/10),
+    grid[1] = 'A' + ((90 + lat) / 10);
-    //                     ord('0') + int(((179-lng)%20)/2),
+    grid[2] = '0' + (((179 - lng) % 20) / 2);
-    //                     ord('0') + (lat+90)%10)
+    grid[3] = '0' + ((90 + lat) % 10);
+    grid[4] = 0;
 
-    // if g[0:2] == "KA":
+    if ((grid[0] == 'K') && (grid[1] == 'A')) {
-    //     // really + signal strength
+        // really + signal strength
-    //     sig = int(g[2:4]) - 50
+        //     sig = int(g[2:4]) - 50
-    //     return "+%02d" % (sig)
+        //     return "+%02d" % (sig)
-
+        return;
-    // if g[0:2] == "LA":
+    }
-    //     // really R+ signal strength
+    else if ((grid[0] == 'L') && (grid[1] == 'A')) {
-    //     sig = int(g[2:4]) - 50
+        // really R+ signal strength
-    //     return "R+%02d" % (sig)    
+        //     sig = int(g[2:4]) - 50
-
+        //     return "R+%02d" % (sig)    
-    grid[0] = 0;
+        return;
+    }
 }
 
 
 void unpacktext(uint32_t nc1, uint32_t nc2, uint16_t ng, char *text) {
-    uint32_t nc3 = ng & 0x7FFF;
+    uint32_t nc3 = (ng & 0x7FFF);
 
-    if (nc1 & 1 != 0)
+    // Check for bit 0 and copy it to nc3
+    if ((nc1 & 1) != 0)
         nc3 |= 0x08000;
-    nc1 >>= 1;
 
-    if (nc2 & 1 != 0)
+    if ((nc2 & 1) != 0)
         nc3 |= 0x10000;
+
+    nc1 >>= 1;
     nc2 >>= 1;
 
     for (int i = 4; i >= 0; --i) {
@@ -169,6 +180,7 @@ int unpack(const uint8_t *a72, char *message) {
         return 0;
     }
 
+    // Standard two-call exchange
     char c1[7];
     
     unpackcall(nc1, c1);