From e048c65cdbc034f3dd631752ac51165927976b12 Mon Sep 17 00:00:00 2001
From: Evgeny <izarizar@mail.ru>
Date: Sat, 14 Jan 2017 19:30:03 +0300
Subject: [PATCH] [CEA-708] Added BS command

---
 src/lib_ccx/ccx_decoders_708.c | 41 ++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/src/lib_ccx/ccx_decoders_708.c b/src/lib_ccx/ccx_decoders_708.c
index e78576fc..278be874 100644
--- a/src/lib_ccx/ccx_decoders_708.c
+++ b/src/lib_ccx/ccx_decoders_708.c
@@ -554,6 +554,44 @@ void _dtvcc_process_etx(ccx_dtvcc_service_decoder *decoder)
 	//it can help decoders with screen output, but could it help us?
 }
 
+void _dtvcc_process_bs(ccx_dtvcc_service_decoder *decoder)
+{
+	if (decoder->current_window == -1)
+	{
+		ccx_common_logging.log_ftn("[CEA-708] _dtvcc_process_bs: Window has to be defined first\n");
+		return;
+	}
+
+	//it looks strange, but in some videos (rarely) we have a backspace command
+	//we just print one character over another
+	int cw = decoder->current_window;
+	ccx_dtvcc_window *window = &decoder->windows[cw];
+
+	switch (window->attribs.print_direction)
+	{
+	case CCX_DTVCC_WINDOW_PD_RIGHT_LEFT:
+		if (window->pen_column + 1 < window->col_count)
+			window->pen_column++;
+		break;
+	case CCX_DTVCC_WINDOW_PD_LEFT_RIGHT:
+		if (decoder->windows->pen_column > 0)
+			window->pen_column--;
+		break;
+	case CCX_DTVCC_WINDOW_PD_BOTTOM_TOP:
+		if (window->pen_row + 1 < window->row_count)
+			window->pen_row++;
+		break;
+	case CCX_DTVCC_WINDOW_PD_TOP_BOTTOM:
+		if (window->pen_row > 0)
+			window->pen_row--;
+		break;
+	default:
+		ccx_common_logging.log_ftn("[CEA-708] _dtvcc_process_character: unhandled branch (%02d)\n",
+			window->attribs.print_direction);
+		break;
+	}
+}
+
 void _dtvcc_window_rollup(ccx_dtvcc_service_decoder *decoder, ccx_dtvcc_window *window)
 {
 	for (int i = 0; i < window->row_count - 1; i++)
@@ -1295,6 +1333,9 @@ int _dtvcc_handle_C0(ccx_dtvcc_ctx *dtvcc,
 			case CCX_DTVCC_C0_ETX:
 				_dtvcc_process_etx(decoder);
 				break;
+			case CCX_DTVCC_C0_BS:
+				_dtvcc_process_bs(decoder);
+				break;
 			default:
 				ccx_common_logging.log_ftn("[CEA-708] _dtvcc_handle_C0: unhandled branch\n");
 				break;