Added support for interpreting ANSI escape sequences on behalf of

non-ANSI-capable consoles.
2025-12-20 20:10:18 +03:00 · 2006-12-18 00:01:30 +00:00
parent 8a45f619a9
commit 1cd45decc4
2 changed files with 217 additions and 0 deletions
--- a/src/core/ansiesc.c
+++ b/src/core/ansiesc.c
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <string.h>
+#include <assert.h>
+#include <gpxe/ansiesc.h>
+
+/** @file
+ *
+ * ANSI escape sequences
+ *
+ */
+
+/**
+ * Call ANSI escape sequence handler
+ *
+ * @v handlers		List of escape sequence handlers
+ * @v function		Control function identifier
+ * @v count		Parameter count
+ * @v params		Parameter list
+ */
+static void ansiesc_call_handler ( struct ansiesc_handler *handlers,
+				   unsigned int function, int count,
+				   int params[] ) {
+	struct ansiesc_handler *handler;
+
+	for ( handler = handlers ; handler->function ; handler++ ) {
+		if ( handler->function == function ) {
+			handler->handle ( count, params );
+			break;
+		}
+	}
+}
+
+/**
+ * Process character that may be part of ANSI escape sequence
+ *
+ * @v ctx		ANSI escape sequence context
+ * @v c			Character
+ * @ret c		Original character if not part of escape sequence
+ * @ret <0		Character was part of escape sequence
+ *
+ * ANSI escape sequences will be plucked out of the character stream
+ * and interpreted; once complete they will be passed to the
+ * appropriate handler if one exists in this ANSI escape sequence
+ * context.
+ *
+ * In the interests of code size, we are rather liberal about the
+ * sequences we are prepared to accept as valid.
+ */
+int ansiesc_process ( struct ansiesc_context *ctx, int c ) {
+	if ( ctx->count == 0 ) {
+		if ( c == ESC ) {
+			/* First byte of CSI : begin escape sequence */
+			ctx->count = 1;
+			memset ( ctx->params, 0xff, sizeof ( ctx->params ) );
+			ctx->function = 0;
+			return -1;
+		} else {
+			/* Normal character */
+			return c;
+		}
+	} else {
+		if ( c == '[' ) {
+			/* Second byte of CSI : do nothing */
+		} else if ( ( c >= '0' ) && ( c <= '9' ) ) {
+			/* Parameter Byte : part of a parameter value */
+			int *param = &ctx->params[ctx->count - 1];
+			if ( *param < 0 )
+				*param = 0;
+			*param = ( ( *param * 10 ) + ( c - '0' ) );
+		} else if ( c == ';' ) {
+			/* Parameter Byte : parameter delimiter */
+			ctx->count++;
+			if ( ctx->count > ( sizeof ( ctx->params ) /
+					    sizeof ( ctx->params[0] ) ) ) {
+				/* Excessive parameters : abort sequence */
+				ctx->count = 0;
+				DBG ( "Too many parameters in ANSI escape "
+				      "sequence\n" );
+			}
+		} else if ( ( c >= 0x20 ) && ( c <= 0x2f ) ) {
+			/* Intermediate Byte */
+			ctx->function <<= 8;
+			ctx->function |= c;
+		} else {
+			/* Treat as Final Byte.  Zero ctx->count before 
+			 * calling handler to avoid potential infinite loops.
+			 */
+			int count = ctx->count;
+			ctx->count = 0;
+			ctx->function <<= 8;
+			ctx->function |= c;
+			ansiesc_call_handler ( ctx->handlers, ctx->function,
+					       count, ctx->params );
+		}
+		return -1;
+	}
+}