[PATCH 02/11] vt: move unicode processing to a separate file

Nicolas Pitre
2025-04-10T01:19:03Z

From: Nicolas Pitre <npitre@baylibre.com>

This will make it easier to maintain. Also make it depend on
CONFIG_CONSOLE_TRANSLATIONS.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
---
drivers/tty/vt/Makefile | 3 ++-
drivers/tty/vt/ucs_width.c | 45 ++++++++++++++++++++++++++++++++++++++
drivers/tty/vt/vt.c | 40 +--------------------------------
include/linux/consolemap.h | 6 +++++
4 files changed, 54 insertions(+), 40 deletions(-)
create mode 100644 drivers/tty/vt/ucs_width.c

diff --git a/drivers/tty/vt/Makefile b/drivers/tty/vt/Makefile
index 2c8ce8b592..bee69277bb 100644
--- a/drivers/tty/vt/Makefile
+++ b/drivers/tty/vt/Makefile
@@ -7,7 +7,8 @@ FONTMAPFILE = cp437.uni
obj-$(CONFIG_VT) += vt_ioctl.o vc_screen.o \
selection.o keyboard.o \
vt.o defkeymap.o
-obj-$(CONFIG_CONSOLE_TRANSLATIONS) += consolemap.o consolemap_deftbl.o
+obj-$(CONFIG_CONSOLE_TRANSLATIONS) += consolemap.o consolemap_deftbl.o \
+ ucs_width.o

# Files generated that shall be removed upon make clean
clean-files := consolemap_deftbl.c defkeymap.c
diff --git a/drivers/tty/vt/ucs_width.c b/drivers/tty/vt/ucs_width.c
new file mode 100644
index 0000000000..5f0bde30a1
--- /dev/null
+++ b/drivers/tty/vt/ucs_width.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/types.h>
+#include <linux/array_size.h>
+#include <linux/bsearch.h>
+#include <linux/consolemap.h>
+
+/* ucs_is_double_width() is based on the wcwidth() implementation by
+ * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
+ * Latest version: https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
+ */
+
+struct interval {
+ uint32_t first;
+ uint32_t last;
+};
+
+static int ucs_cmp(const void *key, const void *elt)
+{
+ uint32_t cp = *(uint32_t *)key;
+ struct interval e = *(struct interval *) elt;
+
+ if (cp > e.last)
+ return 1;
+ else if (cp < e.first)
+ return -1;
+ return 0;
+}
+
+static const struct interval double_width[] = {
+ { 0x1100, 0x115F }, { 0x2329, 0x232A }, { 0x2E80, 0x303E },
+ { 0x3040, 0xA4CF }, { 0xAC00, 0xD7A3 }, { 0xF900, 0xFAFF },
+ { 0xFE10, 0xFE19 }, { 0xFE30, 0xFE6F }, { 0xFF00, 0xFF60 },
+ { 0xFFE0, 0xFFE6 }, { 0x20000, 0x2FFFD }, { 0x30000, 0x3FFFD }
+};
+
+bool ucs_is_double_width(uint32_t cp)
+{
+ if (cp < double_width[0].first ||
+ cp > double_width[ARRAY_SIZE(double_width) - 1].last)
+ return false;
+
+ return bsearch(&cp, double_width, ARRAY_SIZE(double_width),
+ sizeof(struct interval), ucs_cmp) != NULL;
+}
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index b5f3c8a818..bcb508bc15 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -104,7 +104,6 @@
#include <linux/uaccess.h>
#include <linux/kdb.h>
#include <linux/ctype.h>
-#include <linux/bsearch.h>
#include <linux/gcd.h>

#define MAX_NR_CON_DRIVER 16
@@ -2712,43 +2711,6 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, u8 c)
}
}

-/* is_double_width() is based on the wcwidth() implementation by
- * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
- * Latest version: https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
- */
-struct interval {
- uint32_t first;
- uint32_t last;
-};
-
-static int ucs_cmp(const void *key, const void *elt)
-{
- uint32_t ucs = *(uint32_t *)key;
- struct interval e = *(struct interval *) elt;
-
- if (ucs > e.last)
- return 1;
- else if (ucs < e.first)
- return -1;
- return 0;
-}
-
-static int is_double_width(uint32_t ucs)
-{
- static const struct interval double_width[] = {
- { 0x1100, 0x115F }, { 0x2329, 0x232A }, { 0x2E80, 0x303E },
- { 0x3040, 0xA4CF }, { 0xAC00, 0xD7A3 }, { 0xF900, 0xFAFF },
- { 0xFE10, 0xFE19 }, { 0xFE30, 0xFE6F }, { 0xFF00, 0xFF60 },
- { 0xFFE0, 0xFFE6 }, { 0x20000, 0x2FFFD }, { 0x30000, 0x3FFFD }
- };
- if (ucs < double_width[0].first ||
- ucs > double_width[ARRAY_SIZE(double_width) - 1].last)
- return 0;
-
- return bsearch(&ucs, double_width, ARRAY_SIZE(double_width),
- sizeof(struct interval), ucs_cmp) != NULL;
-}
-
struct vc_draw_region {
unsigned long from, to;
int x;
@@ -2953,7 +2915,7 @@ static int vc_con_write_normal(struct vc_data *vc, int tc, int c,
bool inverse = false;

if (vc->vc_utf && !vc->vc_disp_ctrl) {
- if (is_double_width(c))
+ if (ucs_is_double_width(c))
width = 2;
}

diff --git a/include/linux/consolemap.h b/include/linux/consolemap.h
index c35db4896c..caf079bcb8 100644
--- a/include/linux/consolemap.h
+++ b/include/linux/consolemap.h
@@ -28,6 +28,7 @@ int conv_uni_to_pc(struct vc_data *conp, long ucs);
u32 conv_8bit_to_uni(unsigned char c);
int conv_uni_to_8bit(u32 uni);
void console_map_init(void);
+bool ucs_is_double_width(uint32_t cp);
#else
static inline u16 inverse_translate(const struct vc_data *conp, u16 glyph,
bool use_unicode)
@@ -57,6 +58,11 @@ static inline int conv_uni_to_8bit(u32 uni)
}

static inline void console_map_init(void) { }
+
+static inline bool ucs_is_double_width(uint32_t cp)
+{
+ return false;
+}
#endif /* CONFIG_CONSOLE_TRANSLATIONS */

#endif /* __LINUX_CONSOLEMAP_H__ */
--
2.49.0