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changeset 46:f977027774cb

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trau-parse: add support for D144 decoding
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 24 Sep 2024 17:02:59 +0000
parents 59d1d15b6f7e
children 7119884f6afe
files trau-decode/parse-main.c
diffstat 1 files changed, 54 insertions(+), 11 deletions(-) [+]
line wrap: on
line diff
--- a/trau-decode/parse-main.c	Fri Sep 13 17:37:21 2024 +0000
+++ b/trau-decode/parse-main.c	Tue Sep 24 17:02:59 2024 +0000
@@ -19,6 +19,11 @@
 	GOT_8_ZEROS,
 	SYNCED
 } state;
+static enum {
+	NOT_D144,
+	D144_SYNC,
+	D144_EDATA,
+} d144_state;
 static unsigned hunt_for_0_count, frame_pos_count;
 static uint8_t in_frame_2bit[160], frame_bits[320], d_bits[260];
 
@@ -165,30 +170,61 @@
 	case 0x14:
 		fputs(" (D144 sync)", stdout);
 		break;
+	case 0x1F:
+		fputs(" (E-TRAU)", stdout);
+		break;
 	}
 	putchar('\n');
-	c6_11 = bits_to_num(frame_bits + 22, 6);
-	printf("  C6-C11: %u\n", c6_11);
-	printf("  C12=%u C13=%u C14=%u C15=%u\n", frame_bits[28],
-		frame_bits[29], frame_bits[30], frame_bits[31]);
+	if (c1_5 == 0x14)
+		d144_state = D144_SYNC;
+	else if (c1_5 == 0x1F &&
+		 (d144_state == D144_SYNC || d144_state == D144_EDATA))
+		d144_state = D144_EDATA;
+	else
+		d144_state = NOT_D144;
 	switch (c1_5) {
 	case 0x02:
 	case 0x1C:
+	case 0x1A:
+		c6_11 = bits_to_num(frame_bits + 22, 6);
+		printf("  C6-C11: %u\n", c6_11);
+		printf("  C12=%u C13=%u C14=%u C15=%u\n", frame_bits[28],
+			frame_bits[29], frame_bits[30], frame_bits[31]);
 		collect_d_bits();
-		print_fr_frame(d_bits);
-		break;
-	case 0x1A:
-		collect_d_bits();
-		check_efr_crc(d_bits);
-		print_efr_frame(d_bits);
 		break;
 	case 0x08:
 	case 0x09:
 	case 0x16:
 	case 0x17:
 	case 0x14:
+		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_frame();
 		return;
+	case 0x1F:
+		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]);
+		return;
+	default:
+		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]);
+	}
+	switch (c1_5) {
+	case 0x02:
+	case 0x1C:
+		print_fr_frame(d_bits);
+		break;
+	case 0x1A:
+		check_efr_crc(d_bits);
+		print_efr_frame(d_bits);
+		break;
 	}
 	printf("  C16=%u C17=%u C18=%u C19=%u C20=%u C21=%u\n",
 		frame_bits[310], frame_bits[311], frame_bits[312],
@@ -224,7 +260,13 @@
 static void
 check_sync()
 {
-	if (check_sync_zeros() && check_sync_ones())
+	int sync_res;
+
+	if (d144_state == D144_EDATA)
+		sync_res = check_sync_zeros() && frame_bits[16];
+	else
+		sync_res = check_sync_zeros() && check_sync_ones();
+	if (sync_res)
 		return;
 	printf("Bad frame sync, returning to hunt state\n");
 	state = HUNT_FOR_0;
@@ -315,6 +357,7 @@
 	}
 	right_shift = (3 - subslot) * 2;
 	state = HUNT_FOR_0;
+	d144_state = NOT_D144;
 	for (file_offset = 0; ; file_offset++) {
 		inb = getc(inf);
 		if (inb < 0)