;;-*-Lisp-*-
(in-package goal)

;; name: gstring.gc
;; name in dgo: gstring
;; dgos: KERNEL

;; Note on strings:
;;  the allocated length does not include an extra byte on the end for the null terminator!

(defmethod length string ((obj string))
  ; Get the length of a string. Like strlen
  (let ((str-ptr (-> obj data)))
    (while (!= 0 (-> str-ptr 0))
      (set! str-ptr (the (pointer uint8) (&+ str-ptr 1)))
      )
    (- (the int str-ptr) (the int (-> obj data)))
    )
  )

(defmethod asize-of string ((obj string))
  ;; get the size in bytes of a string.
  ;; BUG - string should probably be (-> obj type), not that it matters, I don't think
  ;;  anybody makes a subclass of string.
  (+ (-> obj allocated-length) 1 (-> string size))
  )

(defun copy-string<-string ((dst string) (src string))
  "Copy data from one string to another, like strcpy"
  (let ((dst-ptr (-> dst data))
        (src-ptr (-> src data))
        )
    (while (!= 0 (-> src-ptr))
      (set! (-> dst-ptr) (-> src-ptr))
      (&+! dst-ptr 1)
      (&+! src-ptr 1)
      )
    )
  )

(defmethod new string ((allocation symbol) (type-to-make type) (size int) (other string))
  "Create a new string of the given size. If other is not #f, copy data from it."
  (cond
    (other
      (let* ((desired-size (max (length other) size))
             (new-obj (object-new (+ desired-size 1 (-> type-to-make size))))
             )
        (set! (-> new-obj allocated-length) size)
        (copy-string<-string new-obj other)
        new-obj
        )
      )
    (else
      (let ((new-obj (object-new (+ 1 size (-> type-to-make size)))))
        (set! (-> new-obj allocated-length) size)
        new-obj
        )
      )
    )
  )

(defun charp<-string ((dst (pointer uint8)) (src-string string))
  "Copy a GOAL string into a character array."
  (let ((src (-> src-string data)))
    (while (!= 0 (-> src))
      (set! (-> dst) (-> src))
      (&+! dst 1)
      (&+! src 1)
      )
    (set! (-> dst) 0)
    0
    )
  )