From 4abab5ad6c8465a7528ccdd5f49367da05f78bbd Mon Sep 17 00:00:00 2001
From: Vladimir Azarov <avm@intermediate-node.net>
Date: Tue, 1 Oct 2024 15:47:05 +0200
Subject: Initial version

---
 src/multibyte/wcsrtombs.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 src/multibyte/wcsrtombs.c

(limited to 'src/multibyte/wcsrtombs.c')

diff --git a/src/multibyte/wcsrtombs.c b/src/multibyte/wcsrtombs.c
new file mode 100644
index 0000000..b5713ae
--- /dev/null
+++ b/src/multibyte/wcsrtombs.c
@@ -0,0 +1,55 @@
+#include <wchar.h>
+
+size_t wcsrtombs(char *restrict s, const wchar_t **restrict ws, size_t n, mbstate_t *restrict st)
+{
+	const wchar_t *ws2;
+	char buf[4];
+	size_t N = n, l;
+	if (!s) {
+		for (n=0, ws2=*ws; *ws2; ws2++) {
+			if (*ws2 >= 0x80u) {
+				l = wcrtomb(buf, *ws2, 0);
+				if (!(l+1)) return -1;
+				n += l;
+			} else n++;
+		}
+		return n;
+	}
+	while (n>=4) {
+		if (**ws-1u >= 0x7fu) {
+			if (!**ws) {
+				*s = 0;
+				*ws = 0;
+				return N-n;
+			}
+			l = wcrtomb(s, **ws, 0);
+			if (!(l+1)) return -1;
+			s += l;
+			n -= l;
+		} else {
+			*s++ = **ws;
+			n--;
+		}
+		(*ws)++;
+	}
+	while (n) {
+		if (**ws-1u >= 0x7fu) {
+			if (!**ws) {
+				*s = 0;
+				*ws = 0;
+				return N-n;
+			}
+			l = wcrtomb(buf, **ws, 0);
+			if (!(l+1)) return -1;
+			if (l>n) return N-n;
+			wcrtomb(s, **ws, 0);
+			s += l;
+			n -= l;
+		} else {
+			*s++ = **ws;
+			n--;
+		}
+		(*ws)++;
+	}
+	return N;
+}
-- 
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