import newlib-2000-02-17 snapshot

newlib/libc/stdlib/mblen.c

@@ -0,0 +1,66 @@
+/*
+FUNCTION
+<<mblen>>---minimal multibyte length function
+
+INDEX
+	mblen
+
+ANSI_SYNOPSIS
+	#include <stdlib.h>
+	int mblen(const char *<[s]>, size_t <[n]>);
+
+TRAD_SYNOPSIS
+	#include <stdlib.h>
+	int mblen(<[s]>, <[n]>)
+	const char *<[s]>;
+	size_t <[n]>;
+
+DESCRIPTION
+When MB_CAPABLE is not defined, this is a minimal ANSI-conforming 
+implementation of <<mblen>>.  In this case, the
+only ``multi-byte character sequences'' recognized are single bytes,
+and thus <<1>> is returned unless <[s]> is the null pointer or
+has a length of 0 or is the empty string.
+
+When MB_CAPABLE is defined, this routine calls <<_mbtowc_r>> to perform
+the conversion, passing a state variable to allow state dependent
+decoding.  The result is based on the locale setting which may
+be restricted to a defined set of locales.
+
+RETURNS
+This implementation of <<mblen>> returns <<0>> if
+<[s]> is <<NULL>> or the empty string; it returns <<1>> if not MB_CAPABLE or
+the character is a single-byte character; it returns <<-1>>
+if the multi-byte character is invalid; otherwise it returns
+the number of bytes in the multibyte character.
+
+PORTABILITY
+<<mblen>> is required in the ANSI C standard.  However, the precise
+effects vary with the locale.
+
+<<mblen>> requires no supporting OS subroutines.
+*/
+
+#ifndef _REENT_ONLY
+
+#include <stdlib.h>
+
+int
+_DEFUN (mblen, (s, n), 
+        const char *s _AND
+        size_t n)
+{
+#ifdef MB_CAPABLE
+        static int state;
+
+        return _mbtowc_r (_REENT, NULL, s, n, &state);
+#else /* not MB_CAPABLE */
+        if (s == NULL || *s == '\0')
+                return 0;
+        if (n == 0)
+                return -1;
+        return 1;
+#endif /* not MB_CAPABLE */
+}
+
+#endif /* !_REENT_ONLY */