Port basic Linux kernel NLS functions: utf8_to_utf32() and
utf8s_to_utf16s() in order to support porting kernel code that uses
them.
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
include/linux/nls.h | 40 ++++++++++++++
lib/Kconfig | 3 +
lib/Makefile | 1 +
lib/nls_base.c | 131 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 175 insertions(+)
create mode 100644 include/linux/nls.h
create mode 100644 lib/nls_base.c
diff --git a/include/linux/nls.h b/include/linux/nls.h
new file mode 100644
index 000000000..62fb7b5a9
--- /dev/null
+++ b/include/linux/nls.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_NLS_H
+#define _LINUX_NLS_H
+
+/* Unicode has changed over the years. Unicode code points no longer
+ * fit into 16 bits; as of Unicode 5 valid code points range from 0
+ * to 0x10ffff (17 planes, where each plane holds 65536 code points).
+ *
+ * The original decision to represent Unicode characters as 16-bit
+ * wchar_t values is now outdated. But plane 0 still includes the
+ * most commonly used characters, so we will retain it. The newer
+ * 32-bit unicode_t type can be used when it is necessary to
+ * represent the full Unicode character set.
+ */
+
+/* Plane-0 Unicode character */
+typedef u16 wchar_t;
+#define MAX_WCHAR_T 0xffff
+
+/* Arbitrary Unicode character */
+typedef u32 unicode_t;
+
+/* this value hold the maximum octet of charset */
+#define NLS_MAX_CHARSET_SIZE 6 /* for UTF-8 */
+
+/* Byte order for UTF-16 strings */
+enum utf16_endian {
+ UTF16_HOST_ENDIAN,
+ UTF16_LITTLE_ENDIAN,
+ UTF16_BIG_ENDIAN
+};
+
+/* nls_base.c */
+
+extern int utf8_to_utf32(const u8 *s, int len, unicode_t *pu);
+extern int utf8s_to_utf16s(const u8 *s, int len,
+ enum utf16_endian endian, wchar_t *pwcs, int maxlen);
+
+#endif /* _LINUX_NLS_H */
+
diff --git a/lib/Kconfig b/lib/Kconfig
index e048aded8..44f30d824 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -148,4 +148,7 @@ config GENERIC_LIB_LSHRDI3
config GENERIC_LIB_MULDI3
bool
+config NLS
+ bool "Native language support"
+
endmenu
diff --git a/lib/Makefile b/lib/Makefile
index e72aa6655..763516d41 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -67,6 +67,7 @@ obj-y += parseopt.o
obj-y += clz_ctz.o
obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o
obj-$(CONFIG_CRC8) += crc8.o
+obj-$(CONFIG_NLS) += nls_base.o
# GCC library routines
obj-$(CONFIG_GENERIC_LIB_ASHLDI3) += ashldi3.o
diff --git a/lib/nls_base.c b/lib/nls_base.c
new file mode 100644
index 000000000..cd6a5ff12
--- /dev/null
+++ b/lib/nls_base.c
@@ -0,0 +1,131 @@
+/*
+ * linux/fs/nls/nls_base.c
+ *
+ * Native language support--charsets and unicode translations.
+ * By Gordon Chaffee 1996, 1997
+ *
+ * Unicode based case conversion 1999 by Wolfram Pienkoss
+ *
+ */
+#include <common.h>
+#include <linux/nls.h>
+
+/*
+ * Sample implementation from Unicode home page.
+ * http://www.stonehand.com/unicode/standard/fss-utf.html
+ */
+struct utf8_table {
+ int cmask;
+ int cval;
+ int shift;
+ long lmask;
+ long lval;
+};
+
+static const struct utf8_table utf8_table[] =
+{
+ {0x80, 0x00, 0*6, 0x7F, 0, /* 1 byte sequence */},
+ {0xE0, 0xC0, 1*6, 0x7FF, 0x80, /* 2 byte sequence */},
+ {0xF0, 0xE0, 2*6, 0xFFFF, 0x800, /* 3 byte sequence */},
+ {0xF8, 0xF0, 3*6, 0x1FFFFF, 0x10000, /* 4 byte sequence */},
+ {0xFC, 0xF8, 4*6, 0x3FFFFFF, 0x200000, /* 5 byte sequence */},
+ {0xFE, 0xFC, 5*6, 0x7FFFFFFF, 0x4000000, /* 6 byte sequence */},
+ {0, /* end of table */}
+};
+
+#define UNICODE_MAX 0x0010ffff
+#define PLANE_SIZE 0x00010000
+
+#define SURROGATE_MASK 0xfffff800
+#define SURROGATE_PAIR 0x0000d800
+#define SURROGATE_LOW 0x00000400
+#define SURROGATE_BITS 0x000003ff
+
+int utf8_to_utf32(const u8 *s, int inlen, unicode_t *pu)
+{
+ unsigned long l;
+ int c0, c, nc;
+ const struct utf8_table *t;
+
+ nc = 0;
+ c0 = *s;
+ l = c0;
+ for (t = utf8_table; t->cmask; t++) {
+ nc++;
+ if ((c0 & t->cmask) == t->cval) {
+ l &= t->lmask;
+ if (l < t->lval || l > UNICODE_MAX ||
+ (l & SURROGATE_MASK) == SURROGATE_PAIR)
+ return -1;
+ *pu = (unicode_t) l;
+ return nc;
+ }
+ if (inlen <= nc)
+ return -1;
+ s++;
+ c = (*s ^ 0x80) & 0xFF;
+ if (c & 0xC0)
+ return -1;
+ l = (l << 6) | c;
+ }
+ return -1;
+}
+EXPORT_SYMBOL(utf8_to_utf32);
+
+static inline void put_utf16(wchar_t *s, unsigned c, enum utf16_endian endian)
+{
+ switch (endian) {
+ default:
+ *s = (wchar_t) c;
+ break;
+ case UTF16_LITTLE_ENDIAN:
+ *s = __cpu_to_le16(c);
+ break;
+ case UTF16_BIG_ENDIAN:
+ *s = __cpu_to_be16(c);
+ break;
+ }
+}
+
+int utf8s_to_utf16s(const u8 *s, int inlen, enum utf16_endian endian,
+ wchar_t *pwcs, int maxout)
+{
+ u16 *op;
+ int size;
+ unicode_t u;
+
+ op = pwcs;
+ while (inlen > 0 && maxout > 0 && *s) {
+ if (*s & 0x80) {
+ size = utf8_to_utf32(s, inlen, &u);
+ if (size < 0)
+ return -EINVAL;
+ s += size;
+ inlen -= size;
+
+ if (u >= PLANE_SIZE) {
+ if (maxout < 2)
+ break;
+ u -= PLANE_SIZE;
+ put_utf16(op++, SURROGATE_PAIR |
+ ((u >> 10) & SURROGATE_BITS),
+ endian);
+ put_utf16(op++, SURROGATE_PAIR |
+ SURROGATE_LOW |
+ (u & SURROGATE_BITS),
+ endian);
+ maxout -= 2;
+ } else {
+ put_utf16(op++, u, endian);
+ maxout--;
+ }
+ } else {
+ put_utf16(op++, *s++, endian);
+ inlen--;
+ maxout--;
+ }
+ }
+ return op - pwcs;
+}
+EXPORT_SYMBOL(utf8s_to_utf16s);
+
--
2.20.1
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