1 files changed, 47 insertions, 0 deletions
diff --git a/src/stdlib/wcstoumax.c b/src/stdlib/wcstoumax.c
new file mode 100644
index 00000000..a8f4680f
--- /dev/null
+++ b/src/stdlib/wcstoumax.c
@@ -0,0 +1,47 @@
+#include <wchar.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <errno.h>
+
+uintmax_t wcstoumax(const wchar_t *s, wchar_t **p, int base)
+{
+	/* Large enough for largest value in binary */
+	char buf[sizeof(uintmax_t)*8+2];
+	int sign = 0, skipped=0;
+
+	if (!p) p = (wchar_t **)&s;
+
+	if (base && (unsigned)base-2 > 36-2) {
+		*p = (wchar_t *)s;
+		errno = EINVAL;
+		return 0;
+	}
+
+	/* Initial whitespace */
+	for (; iswspace(*s); s++);
+
+	/* Optional sign */
+	if (*s == '-') sign = *s++;
+	else if (*s == '+') s++;
+
+	/* Skip leading zeros but don't allow leading zeros before "0x". */
+	for (; s[0]=='0' && s[1]=='0'; s++) skipped=1;
+	if (skipped && (base==0 || base==16) && (s[1]|32)=='x') {
+		*p = (wchar_t *)(s+1);
+		return 0;
+	}
+
+	/* Convert to normal char string so we can use strtoumax */
+	buf[0] = sign;
+	if (wcstombs(buf+!!sign, s, sizeof buf-1) < 0) return 0;
+	buf[sizeof buf-1]=0;
+
+	/* Compute final position */
+	if (p) {
+		if ((base==0 || base==16) && s[0]=='0' && (s[1]|32)=='x' && iswxdigit(s[2])) s+=2;
+		for(;*s&&((unsigned)*s-'0'<base||((unsigned)*s|32)-'a'<base-10);s++);
+		*p = (wchar_t *)s;
+	}
+
+	return strtoumax(buf, 0, base);
+}