Initial Contribution
diff --git a/libc/stdlib/strntoumax.c b/libc/stdlib/strntoumax.c
new file mode 100644
index 0000000..a151ef5
--- /dev/null
+++ b/libc/stdlib/strntoumax.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <stddef.h>
+#include <stdint.h>
+#include <ctype.h>
+
+static inline int digitval(int ch)
+{
+ unsigned d;
+
+ d = (unsigned)(ch - '0');
+ if (d < 10) return (int)d;
+
+ d = (unsigned)(ch - 'a');
+ if (d < 6) return (int)(d+10);
+
+ d = (unsigned)(ch - 'A');
+ if (d < 6) return (int)(d+10);
+
+ return -1;
+}
+
+uintmax_t
+strntoumax(const char *nptr, char **endptr, int base, size_t n)
+{
+ const unsigned char* p = nptr;
+ const unsigned char* end = p + n;
+ int minus = 0;
+ uintmax_t v = 0;
+ int d;
+
+ /* skip leading space */
+ while (p < end && isspace(*p))
+ p++;
+
+ /* Single optional + or - */
+ if (p < end) {
+ char c = p[0];
+ if ( c == '-' || c == '+' ) {
+ minus = (c == '-');
+ p++;
+ }
+ }
+
+ if ( base == 0 ) {
+ if ( p+2 < end && p[0] == '0' && (p[1] == 'x' || p[1] == 'X') ) {
+ p += 2;
+ base = 16;
+ } else if ( p+1 < end && p[0] == '0' ) {
+ p += 1;
+ base = 8;
+ } else {
+ base = 10;
+ }
+ } else if ( base == 16 ) {
+ if ( p+2 < end && p[0] == '0' && (p[1] == 'x' || p[1] == 'X') ) {
+ p += 2;
+ }
+ }
+
+ while ( p < end && (d = digitval(*p)) >= 0 && d < base ) {
+ v = v*base + d;
+ p += 1;
+ }
+
+ if ( endptr )
+ *endptr = (char *)p;
+
+ return minus ? -v : v;
+}