efi_loader: updating the cursor position
The current coding advances the column by the number of UTF-8 bytes.
The column should be increased by one per unicode character.
The UEFI spec provides advance rules for U+0000, U+0008, U+000A,
and U000D. All other characters, including control characters
U+0007 (bel) and U+0009 (tab), have to increase the column by one.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
index d777db8..10fb224 100644
--- a/lib/efi_loader/efi_console.c
+++ b/lib/efi_loader/efi_console.c
@@ -116,25 +116,36 @@
unsigned int n16 = utf16_strlen(string);
char buf[MAX_UTF8_PER_UTF16 * n16 + 1];
- char *p;
+ u16 *p;
*utf16_to_utf8((u8 *)buf, string, n16) = '\0';
fputs(stdout, buf);
- for (p = buf; *p; p++) {
+ /*
+ * Update the cursor position.
+ *
+ * The UEFI spec provides advance rules for U+0000, U+0008, U+000A,
+ * and U000D. All other characters, including control characters
+ * U+0007 (bel) and U+0009 (tab), have to increase the column by one.
+ */
+ for (p = string; *p; ++p) {
switch (*p) {
- case '\r': /* carriage-return */
- con->cursor_column = 0;
+ case '\b': /* U+0008, backspace */
+ con->cursor_column = max(0, con->cursor_column - 1);
break;
- case '\n': /* newline */
+ case '\n': /* U+000A, newline */
con->cursor_column = 0;
con->cursor_row++;
break;
- case '\t': /* tab, assume 8 char align */
+ case '\r': /* U+000D, carriage-return */
+ con->cursor_column = 0;
break;
- case '\b': /* backspace */
- con->cursor_column = max(0, con->cursor_column - 1);
+ case 0xd800 ... 0xdbff:
+ /*
+ * Ignore high surrogates, we do not want to count a
+ * Unicode character twice.
+ */
break;
default:
con->cursor_column++;