1 files changed, 37 insertions, 0 deletions
diff --git a/libc/misc/internals/ulltostr.c b/libc/misc/internals/ulltostr.c
new file mode 100644
index 000000000..50246d3bc
--- /dev/null
+++ b/libc/misc/internals/ulltostr.c
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2000 Manuel Novoa III
+ *
+ * Note: buf is a pointer to the END of the buffer passed.
+ * Call like this:
+ *     char buf[SIZE], *p;
+ *     p = __ulltostr(buf + sizeof(buf) - 1, ...)
+ *
+ * For long longs of 64 bits, appropriate buffer sizes are:
+ *     base =  2      65  = 64 digits + 1 nul
+ *     base = 10      20  = 19 digits + 1 nul
+ *     base = 16      17  = 16 hex digits + 1 nul
+ */
+
+char *__ulltostr(char *buf, unsigned long long uval, int base, int uppercase)
+{
+    int digit;
+
+    if ((base < 2) || (base > 36)) {
+		return 0;
+    }
+
+    *buf = '\0';
+
+    do {
+		digit = uval % base;
+		uval /= base;
+
+		/* note: slightly slower but generates less code */
+		*--buf = '0' + digit;
+		if (digit > 9) {
+			*buf = (uppercase ? 'A' : 'a') + digit - 10;
+		}
+    } while (uval);
+
+    return buf;
+}