--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/trau-decode/parse-data.c	Sat Feb 08 05:16:35 2025 +0000
@@ -0,0 +1,67 @@
+/*
+ * This module contains a bit of code that has been factored out of
+ * trau-parse program; it handles data frames.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+static unsigned
+bits_to_num(bits, nbits)
+	uint8_t *bits;
+	unsigned nbits;
+{
+	unsigned accum;
+	unsigned n;
+
+	accum = 0;
+	for (n = 0; n < nbits; n++) {
+		accum <<= 1;
+		if (*bits)
+			accum |= 1;
+		bits++;
+	}
+	return accum;
+}
+
+static void
+print_data_subframe(nf, bits)
+	uint8_t *bits;
+{
+	unsigned nb;
+
+	printf("  Data frame %d:", nf);
+	for (nb = 0; nb < 9; nb++) {
+		printf(" %02X", bits_to_num(bits, 8));
+		bits += 8;
+	}
+	putchar('\n');
+}
+
+void
+print_data_frame(frame_bits)
+	uint8_t *frame_bits;
+{
+	printf("  C6-C15: %u%u%u%u%u%u%u%u%u%u\n", frame_bits[22],
+		frame_bits[23], frame_bits[24], frame_bits[25],
+		frame_bits[26], frame_bits[27], frame_bits[28],
+		frame_bits[29], frame_bits[30], frame_bits[31]);
+	print_data_subframe(0, frame_bits + 4 * 8);
+	print_data_subframe(1, frame_bits + 13 * 8);
+	print_data_subframe(2, frame_bits + 22 * 8);
+	print_data_subframe(3, frame_bits + 31 * 8);
+}
+
+void
+print_edata_frame(frame_bits)
+	uint8_t *frame_bits;
+{
+	printf("  C6-C13: %u%u%u%u%u%u%u%u\n", frame_bits[22],
+		frame_bits[23], frame_bits[24], frame_bits[25],
+		frame_bits[26], frame_bits[27], frame_bits[28],
+		frame_bits[29]);
+	printf("  M1=%u M2=%u\n", frame_bits[30], frame_bits[31]);
+}