signed samples; frame shift

rs41/rs41stdin.c

@@ -160,35 +160,30 @@ int read_wav_header(FILE *fp) {
     return 0;
 }
 
-int read_sample(FILE *fp) {  // int = i32_t
-    int byte, i, ret;        // return ui16_t/ui8_t oder EOF
+
+#define EOF_INT  0x1000000
+
+int read_signed_sample(FILE *fp) {  // int = i32_t
+    int byte, i, ret;         //  EOF -> 0x1000000
 
     for (i = 0; i < channels; i++) {
-                          // i = 0: links bzw. mono
+                           // i = 0: links bzw. mono
         byte = fgetc(fp);
-        if (byte == EOF) return EOF;
+        if (byte == EOF) return EOF_INT;
         if (i == 0) ret = byte;
     
         if (bits_sample == 16) {
             byte = fgetc(fp);
-            if (byte == EOF) return EOF;
+            if (byte == EOF) return EOF_INT;
             if (i == 0) ret +=  byte << 8;
         }
 
     }
-                 // unsigned 8/16 bit sample >= 0
-    return ret;  // EOF < 0
-}
 
-int sign(int sample) {
-    int sgn = 0;
-    if (bits_sample == 8) {                         // unsigned char:
-        if (sample & 0x80) sgn = 1; else sgn = -1;  // 00..7F - , 80..FF: +
-    }
-    else if (bits_sample == 16) {
-        if (sample & 0x8000) sgn = -1; else sgn = 1;
-    }
-    return sgn;
+    if (bits_sample ==  8) return ret-128;
+    if (bits_sample == 16) return (short)ret;
+
+    return ret;
 }
 
 int par=1, par_alt=1;
@@ -200,20 +195,20 @@ int read_bits_fsk(FILE *fp, int *bit, int *len) {
 
     n = 0;
     do{
-        sample = read_sample(fp);  // unsigned sample;
-        if (sample == EOF) return EOF; // usample >= 0
-        par_alt = par;
-        par = sign(sample);
+        sample = read_signed_sample(fp);
+        if (sample == EOF_INT) return EOF;
         sample_count++;
+        par_alt = par;
+        par =  (sample >= 0) ? 1 : -1;
         n++;
     } while (par*par_alt > 0);
 
-    l = (float)n / samples_per_bit;  // abw = n % samples_per_bit;
+    l = (float)n / samples_per_bit;
 
     *len = (int)(l+0.5);
 
     if (!option_inv) *bit = (1-par_alt)/2;  // unten 1, oben -1
-    else             *bit = (1+par_alt)/2;  // inverse:
+    else             *bit = (1+par_alt)/2;  // inverse
 
     /* Y-offset ? */
 
@@ -305,12 +300,83 @@ SubHeader, 2byte
 #define pos_GPSecefZ  0x11C  // 4 byte
 
 
+#define pos_Hframe 0x039
+#define HEAD_frame 0x1713  // ^0x6E3B=0x7928
+
+#define pos_Htow   0x093
+#define HEAD_tow   0x9667  // ^0xEA79=0x7C1E
+
+#define pos_Hkoord 0x112
+#define HEAD_koord 0xB9FF  // ^0xC2EA=0x7B15
+
+unsigned shiftLeft(int pos) {
+    unsigned tmp;
+    tmp = (frame[pos+1]<<8) + frame[pos];
+    tmp = (tmp >> 1) & 0xFF;
+    return tmp;
+}
+int shiftRight(int pos) {
+    unsigned tmp;
+    tmp = (frame[pos]<<8) + frame[pos-1];
+    tmp = (tmp >> 7) & 0xFF;
+    return tmp;
+}
+
+void shiftFrame(int pos, int shift) {
+    unsigned byte, byte1, byte2;
+
+    if (shift > 0) {
+        while (pos < FRAME_LEN) {
+            byte = shiftLeft(pos);
+            frame[pos] = byte;
+            pos++;
+        }
+    }
+    if (shift < 0) {
+        byte1 = shiftRight(pos);
+        pos++;
+        while (pos < FRAME_LEN) {
+            byte2 = shiftRight(pos);
+            frame[pos-1] = byte1;
+            byte1 = byte2;
+            pos++;
+        }
+    }
+
+}
+
+int getShift(int pos, unsigned head) {
+    unsigned byte;
+    int shift = 0;
+
+    byte = (frame[pos]<<8) + frame[pos+1];
+    // fprintf(stdout, "0x%04X ", byte );  // HEAD_frame ^ 0x6E38 == 0x7928 ? 
+    if (byte != head) {
+        byte = (shiftLeft(pos)<<8) + shiftLeft(pos+1);
+        //fprintf(stdout, " %04X", byte);
+        if (byte == HEAD_frame) shift = 1;
+        else {
+            byte = (shiftRight(pos)<<8) + shiftRight(pos+1);
+            if (byte == head) shift = -1;
+        }
+        if (!shift) return 0x100;
+        //printf("shift:%2d ", shift);
+    }
+    return shift;
+}
+
 int get_FrameNb() {
     int i;
     unsigned byte;
     ui8_t frnr_bytes[2];
     int frnr;
+/*  int shift = 0;
 
+    shift = getShift(pos_Hframe, HEAD_frame);
+    if (shift == 0x100) return 0x100;
+    //printf("shift:%2d ", shift);
+    shiftFrame(pos_Hframe, shift);
+*/
     for (i = 0; i < 2; i++) {
         byte = xorbyte(pos_FrameNb + i);
         frnr_bytes[i] = byte;
@@ -346,7 +412,13 @@ int get_GPSweek() {
     unsigned byte;
     ui8_t gpsweek_bytes[2];
     int gpsweek;
+/*  int shift = 0;
 
+    shift = getShift(pos_Htow, HEAD_tow);
+    if (shift == 0x100) return 0x100;
+    //printf("shift:%2d ", shift);
+    shiftFrame(pos_Htow, shift);
+*/
     for (i = 0; i < 2; i++) {
         byte = xorbyte(pos_GPSweek + i);
         gpsweek_bytes[i] = byte;
@@ -420,23 +492,6 @@ void ecef2elli(double X[], double *lat, double *lon, double *h) {
     *lon = lam*180/M_PI;
 }
 
-
-#define pos_Hkoord 0x112
-#define HEAD_koord 0xB9FF
-
-unsigned shiftLeft(int pos) {
-    unsigned tmp;
-    tmp = (frame[pos+1]<<8) + frame[pos];
-    tmp = (tmp >> 1) & 0xFF;
-    return tmp;
-}
-int shiftRight(int pos) {
-    unsigned tmp;
-    tmp = (frame[pos]<<8) + frame[pos-1];
-    tmp = (tmp >> 7) & 0xFF;
-    return tmp;
-}
-
 int get_GPSkoord() {
     int i, k;
     unsigned byte;
@@ -519,7 +574,6 @@ int get_Cal() {
 
 /* ------------------------------------------------------------------------------------ */
 
-
 int print_position() {
     int err;