1 files changed, 56 insertions, 0 deletions
diff --git a/userland/libc/stdlib/strtoll.c b/userland/libc/stdlib/strtoll.c
new file mode 100644
index 0000000..486f91d
--- /dev/null
+++ b/userland/libc/stdlib/strtoll.c
@@ -0,0 +1,56 @@
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+
+int get_value(char c, long base);
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/strtoll.html
+long long strtoll(const char *str, char **restrict endptr, int base) {
+  long long ret_value = 0;
+  if (endptr)
+    *endptr = (char *)str;
+  // Ignore inital white-space sequence
+  for (; *str && isspace(*str); str++)
+    ;
+  if (!*str)
+    return ret_value;
+
+  //  int sign = 0;
+  if ('-' == *str) {
+    // FIXME
+    //    sign = 1;
+    str++;
+    assert(0);
+  } else if ('+' == *str) {
+    str++;
+  }
+
+  if (0 == base) {
+    // FIXME
+    assert(0);
+  }
+
+  if (2 <= base && 36 >= base) {
+    for (; *str; str++) {
+      if (ret_value > LLONG_MAX / base) {
+        errno = ERANGE;
+        return LLONG_MAX;
+      }
+      ret_value *= base;
+      int val = get_value(*str, base);
+      if (ret_value > LLONG_MAX - val) {
+        errno = ERANGE;
+        return LLONG_MAX;
+      }
+      ret_value += val;
+    }
+  } else {
+    errno = EINVAL;
+    return 0;
+  }
+  if (endptr)
+    *endptr = (char *)str;
+  return ret_value;
+}