Added support for interpreting ANSI escape sequences on behalf of

non-ANSI-capable consoles.

1 files changed, 103 insertions, 0 deletions

diff --git a/src/include/gpxe/ansiesc.h b/src/include/gpxe/ansiesc.h
new file mode 100644
index 000000000..984858936
--- /dev/null
+++ b/src/include/gpxe/ansiesc.h
@@ -0,0 +1,103 @@
+#ifndef _GPXE_ANSIESC_H
+#define _GPXE_ANSIESC_H
+
+/** @file
+ *
+ * ANSI escape sequences
+ *
+ * ANSI X3.64 (aka ECMA-48 or ISO/IEC 6429, available from
+ * http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-048.pdf)
+ * defines escape sequences consisting of:
+ *
+ *     A Control Sequence Introducer (CSI)
+ *
+ *     Zero or more Parameter Bytes (P)
+ *
+ *     Zero or more Intermediate Bytes (I)
+ *
+ *     A Final Byte (F)
+ *
+ * The CSI consists of ESC (0x1b) followed by "[" (0x5b).  The
+ * Parameter Bytes, for a standardised (i.e. not private or
+ * experimental) sequence, consist of a list of ASCII decimal integers
+ * separated by semicolons.  The Intermediate Bytes (in the range 0x20
+ * to 0x2f) and the Final Byte (in the range 0x40 to 0x4f) determine
+ * the control function.
+ * 
+ */
+
+/** A handler for an escape sequence */
+struct ansiesc_handler {
+	/** The control function identifier
+	 *
+	 * The control function identifier consists of the
+	 * Intermediate Bytes (if any) and the Final Byte.  In
+	 * practice, no more than one immediate byte is ever used, so
+	 * the byte combination can be efficiently expressed as a
+	 * single integer, in the obvious way (with the Final Byte
+	 * being the least significant byte).
+	 */
+	unsigned int function;
+	/** Handle escape sequence
+	 *
+	 * @v count		Parameter count
+	 * @v params		Parameter list
+	 *
+	 * A negative parameter value indicates that the parameter was
+	 * omitted and that the default value for this control
+	 * function should be used.
+	 *
+	 * Since all parameters are optional, there is no way to
+	 * distinguish between "zero parameters" and "single parameter
+	 * omitted".  Consequently, the parameter list will always
+	 * contain at least one item.
+	 */
+	void ( * handle ) ( unsigned int count, int params[] );
+};
+
+/** Maximum number of parameters within a single escape sequence */
+#define ANSIESC_MAX_PARAMS 4
+
+/**
+ * ANSI escape sequence context
+ *
+ * This provides temporary storage for processing escape sequences,
+ * and points to the list of escape sequence handlers.
+ */
+struct ansiesc_context {
+	/** Array of handlers
+	 *
+	 * Must be terminated by a handler with @c function set to
+	 * zero.
+	 */
+	struct ansiesc_handler *handlers;
+	/** Parameter count
+	 *
+	 * Will be zero when not currently in an escape sequence.
+	 */
+	unsigned int count;
+	/** Parameter list */ 
+	int params[ANSIESC_MAX_PARAMS];
+	/** Control function identifier */
+	unsigned int function;
+};
+
+/** Escape character */
+#define ESC 0x1b
+
+/** Control Sequence Introducer */
+#define CSI "\033["
+
+/**
+ * @defgroup ansifuncs ANSI escape sequence function identifiers
+ * @{
+ */
+
+/** Character and line position */
+#define ANSIESC_HVP 'f'
+
+/** @} */
+
+extern int ansiesc_process ( struct ansiesc_context *ctx, int c );
+
+#endif /* _GPXE_ANSIESC_H */