+
+(defun prefixed-fixnum-string (num pchar len)
+ "Outputs a string of LEN digit with an optional initial character PCHAR.
+Leading zeros are present."
+ (declare (optimize (speed 3) (safety 0) (space 0))
+ (type fixnum num len))
+ (when pchar
+ (incf len))
+ (do* ((zero-code (char-code #\0))
+ (result (make-string len :initial-element #\0))
+ (minus? (minusp num))
+ (val (if minus? (- 0 num) num) (floor (/ val 10)))
+ (pos (1- len) (1- pos))
+ (mod (mod val 10) (mod val 10)))
+ ((or (zerop val) (minusp pos))
+ (when pchar
+ (setf (schar result 0) pchar))
+ (when minus? (setf (schar result (if pchar 1 0)) #\-))
+ result)
+ (declare (fixnum val mod zero-code pos) (simple-string result))
+ (setf (schar result pos) (code-char (+ zero-code mod)))))
+
+(defun integer-string (num len)
+ "Outputs a string of LEN digit with an optional initial character PCHAR.
+Leading zeros are present."
+ (declare (optimize (speed 3) (safety 0) (space 0))
+ (type fixnum len) (type integer num))
+ (when pchar
+ (incf len))
+ (do* ((zero-code (char-code #\0))
+ (result (make-string len :initial-element #\0))
+ (minus? (minusp num))
+ (val (if minus? (- 0 num) num) (floor (/ val 10)))
+ (pos (1- len) (1- pos))
+ (mod (mod val 10) (mod val 10)))
+ ((or (zerop val) (minusp pos))
+ (when pchar
+ (setf (schar result 0) pchar))
+ (when minus? (setf (schar result (if pchar 1 0)) #\-))
+ result)
+ (declare (fixnum mod zero-code pos) (simple-string result) (integer val))
+ (setf (schar result pos) (code-char (+ zero-code mod)))))