libedit: improve multibyte support

Until this commit libedit only supported UTF-8 for multibyte charset
Improve it to support other multibyte charsets

Tested with eucJP and SJIS charsets.
Note that this change as been review and committed in upstream libedit
as well via christos@NetBSD

Submitted by:	naito.yuichiro _at_ gmail.com
Reviewed by:	bapt, pfg, yuripv, 0mp
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D17903

5 files changed, 12 insertions, 24 deletions

diff --git a/lib/libedit/chartype.c b/lib/libedit/chartype.c
index 44fb953f8581..a695bdc384ec 100644
--- a/lib/libedit/chartype.c
+++ b/lib/libedit/chartype.c
@@ -37,6 +37,7 @@ __RCSID("$NetBSD: chartype.c,v 1.23 2016/02/28 23:02:24 christos Exp $");
 __FBSDID("$FreeBSD$");
 
 #include <ctype.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -182,17 +183,13 @@ ct_decode_argv(int argc, const char *argv[], ct_buffer_t *conv)
 protected size_t
 ct_enc_width(Char c)
 {
-	/* UTF-8 encoding specific values */
-	if (c < 0x80)
-		return 1;
-	else if (c < 0x0800)
-		return 2;
-	else if (c < 0x10000)
-		return 3;
-	else if (c < 0x110000)
-		return 4;
-	else
-		return 0; /* not a valid codepoint */
+	mbstate_t ps = (mbstate_t){{0}};
+	size_t len;
+	char cbuf[MB_LEN_MAX];
+	len = ct_wcrtomb(cbuf, c, &ps);
+	if (len == (size_t)-1)
+		return (0);
+	return (len);
 }
 
 protected ssize_t
diff --git a/lib/libedit/chartype.h b/lib/libedit/chartype.h
index 9f5e7e407c8c..317740f0d404 100644
--- a/lib/libedit/chartype.h
+++ b/lib/libedit/chartype.h
@@ -56,6 +56,7 @@
 
 #define ct_wctob             wctob
 #define ct_wctomb            wctomb
+#define ct_wcrtomb           wcrtomb
 #define ct_wctomb_reset      wctomb(0,0)
 #define ct_wcstombs          wcstombs
 #define ct_mbstowcs          mbstowcs
@@ -109,6 +110,7 @@ Width(wchar_t c)
 
 #define ct_wctob(w)          ((int)(w))
 #define ct_wctomb            error
+#define ct_wcrtomb           error
 #define ct_wctomb_reset
 #define ct_wcstombs(a, b, c)    (strncpy(a, b, c), strlen(a))
 #define ct_mbstowcs(a, b, c)    (strncpy(a, b, c), strlen(a))
diff --git a/lib/libedit/el.c b/lib/libedit/el.c
index 81020b182708..ea5b9b78d2f3 100644
--- a/lib/libedit/el.c
+++ b/lib/libedit/el.c
@@ -99,10 +99,6 @@ el_init_fd(const char *prog, FILE *fin, FILE *fout, FILE *ferr,
          * Initialize all the modules. Order is important!!!
          */
 	el->el_flags = 0;
-	if (setlocale(LC_CTYPE, NULL) != NULL){
-		if (strcmp(nl_langinfo(CODESET), "UTF-8") == 0)
-			el->el_flags |= CHARSET_IS_UTF8;
-	}
 
 	if (terminal_init(el) == -1) {
 		el_free(el->el_prog);
@@ -293,7 +289,7 @@ FUN(el,set)(EditLine *el, int op, ...)
 		void *ptr = va_arg(ap, void *);
 
 		rv = hist_set(el, func, ptr);
-		if (!(el->el_flags & CHARSET_IS_UTF8))
+		if (MB_CUR_MAX == 1)
 			el->el_flags &= ~NARROW_HISTORY;
 		break;
 	}
diff --git a/lib/libedit/el.h b/lib/libedit/el.h
index d6b69fc179ef..8b728742911a 100644
--- a/lib/libedit/el.h
+++ b/lib/libedit/el.h
@@ -56,7 +56,6 @@
 #define	NO_TTY		0x02
 #define	EDIT_DISABLED	0x04
 #define	UNBUFFERED	0x08
-#define	CHARSET_IS_UTF8 0x10
 #define	NARROW_HISTORY	0x40
 
 typedef unsigned char el_action_t;	/* Index to command array	*/
diff --git a/lib/libedit/read.c b/lib/libedit/read.c
index 66e266b5f79b..054177348dd3 100644
--- a/lib/libedit/read.c
+++ b/lib/libedit/read.c
@@ -363,13 +363,7 @@ read_char(EditLine *el, wchar_t *cp)
 				goto again;
 			}
 		case (size_t)-2:
-			/*
-			 * We don't support other multibyte charsets.
-			 * The second condition shouldn't happen
-			 * and is here merely for additional safety.
-			 */
-			if ((el->el_flags & CHARSET_IS_UTF8) == 0 ||
-			    cbp >= MB_LEN_MAX) {
+			if (cbp >= MB_LEN_MAX) {
 				errno = EILSEQ;
 				*cp = L'\0';
 				return -1;