Convert xstrfmon() into a wide-character version xwcsfmon()

Also work around buggy implementations of strfmon() that do not copy
complete multibyte sequences that may be part of a locale's
mon_thousands_sep, thousands_sep, mon_decimal_point or decimal_point.

src/intf.c

@@ -1467,21 +1467,10 @@ int vmkchstr (chtype *restrict chbuf, int chbufsize, chtype attr_norm,
 
 		case L'N':
 		    // Insert a monetary amount (double) into the output
-		    {
-			/* strfmon() is not available in a wide-char
-			   version, so we need a multibyte char buffer */
-			char *buf = xmalloc(BUFSIZE);
-
-			if (xstrfmon(buf, BUFSIZE, spec->flag_nosym ? "%!n" : "%n",
-				     format_arg[spec->arg_num].a.a_double) < 0) {
-			    saved_errno = errno;
-			    free(buf);
-			    errno = saved_errno;
-			    goto error;
-			}
-
-			xmbstowcs(fmtbuf, buf, BUFSIZE);
-			free(buf);
+		    if (xwcsfmon(fmtbuf, BUFSIZE, spec->flag_nosym ?
+				 "%!n" : "%n",
+				 format_arg[spec->arg_num].a.a_double) < 0) {
+			goto error;
 		    }
 
 		    str = fmtbuf;

src/utils.c

@@ -570,22 +570,26 @@ void init_locale (void)
 
 
 /***********************************************************************/
-// xstrfmon: Convert monetary value to a string
+// xwcsfmon: Convert monetary value to a wide-character string
 
-ssize_t xstrfmon (char *restrict buf, size_t maxsize,
+ssize_t xwcsfmon (wchar_t *restrict buf, size_t maxsize,
 		  const char *restrict format, double val)
 {
-    /* Current and previous versions of ISO/IEC 9945-1 (POSIX), particularly
+    ssize_t ret;
+    char *s = xmalloc(BUFSIZE);
+
+
+    /* Current and previous versions of ISO/IEC 9945-1 (POSIX), namely
        SUSv3 (2001) and SUSv4 (2008), require strfmon() to return rather
        meaningless strings when used with the POSIX "C" locale.  In
        particular, the standard POSIX locale does not define a currency
        symbol, a monetary radix symbol (decimal point) or a negative
        sign.  This means strfmon(..., "%n", -123.45) is supposed to
-       produce "12345" instead of something like "$-123.45"!  This
-       function overcomes these limitations by using snprintf(). */
+       produce "12345" instead of something like "-$123.45"!  The
+       following code overcomes these limitations by using snprintf(). */
 
     if (! is_posix_locale) {
-	return strfmon(buf, maxsize, format, val);
+	ret = strfmon(s, BUFSIZE, format, val);
     } else {
 	/* The current implementation assumes the monetary decimal point
 	   is overridden to "." (ie, MOD_POSIX_MON_DECIMAL_POINT == "."),
@@ -609,22 +613,49 @@ ssize_t xstrfmon (char *restrict buf, size_t maxsize,
 
 	if (strcmp(format, "%n") == 0) {
 	    if (val >= 0.0) {
-		return snprintf(buf, maxsize, MOD_POSIX_FMT_POS, val);
+		ret = snprintf(s, BUFSIZE, MOD_POSIX_FMT_POS, val);
 	    } else {
-		return snprintf(buf, maxsize, MOD_POSIX_FMT_NEG, -val);
+		ret = snprintf(s, BUFSIZE, MOD_POSIX_FMT_NEG, -val);
 	    }
 	} else if (strcmp(format, "%!n") == 0) {
 	    if (val >= 0.0) {
-		return snprintf(buf, maxsize, MOD_POSIX_FMT_POS_NOSYM, val);
+		ret = snprintf(s, BUFSIZE, MOD_POSIX_FMT_POS_NOSYM, val);
 	    } else {
-		return snprintf(buf, maxsize, MOD_POSIX_FMT_NEG_NOSYM, -val);
+		ret = snprintf(s, BUFSIZE, MOD_POSIX_FMT_NEG_NOSYM, -val);
 	    }
 	} else {
 	    // Other strfmon() formats are not supported
 	    errno = EINVAL;
-	    return -1;
+	    ret = -1;
 	}
     }
+
+    if (ret >= BUFSIZE) {
+	// Truncate the too-long output with a terminating NUL
+	s[BUFSIZE - 1] = '\0';
+    }
+
+    if (ret >= 0) {
+	xmbstowcs(buf, s, maxsize);
+
+	/* Some buggy implementations of strfmon(), such as that on
+	   FreeBSD and Cygwin, assume localeconv.mon_thousands_sep and
+	   similar strings contain either a single char or NUL instead of
+	   a multibyte character string.  However, this assumption fails
+	   on locales such as ru_RU.UTF-8 which use U+00A0 NO-BREAK SPACE
+	   for mon_thousands_sep (stored in UTF-8 as 0xC2 0xA0.  As a
+	   result, incomplete character sequences are copied, which are
+	   translated to EILSEQ_REPL characters by xmbstowcs() above.
+	   Fix such characters by replacing them with a space. */
+	for (wchar_t *p = buf; *p != L'\0'; p++) {
+	    if (*p == EILSEQ_REPL) {
+		*p = L' ';
+	    }
+	}
+    }
+
+    free(s);
+    return ret;
 }
 
 

src/utils.h

@@ -239,18 +239,19 @@ extern void init_locale (void);
 
 
 /*
-  Function:   xstrfmon - Convert monetary value to a string
+  Function:   xwcsfmon - Convert monetary value to a wide-character string
   Parameters: buf      - Buffer to receive result
-              maxsize  - Maximum size of buffer
+              maxsize  - Maximum size of buffer, in multiples of wchar_t
               format   - strfmon() format to use
               val      - Monetary value to convert
   Returns:    ssize_t  - Size of returned string
 
   This function calls strfmon() to convert val to a suitable monetary
-  value string, making appropriate adjustments if the POSIX locale is in
-  effect.
+  value string, then converts the result to a wide-character string and
+  places it in buf.  It makes appropriate adjustments to the output if
+  the POSIX locale is in effect or if the locale uses no-break spaces.
 */
-extern ssize_t xstrfmon (char *restrict buf, size_t maxsize,
+extern ssize_t xwcsfmon (wchar_t *restrict buf, size_t maxsize,
 			 const char *restrict format, double val);