;;;; blob-hexadecimal.scm  -*- Scheme -*-
;;;; Kon Lovett, Jul '18
;;;; Kon Lovett, Apr '11

(declare
  (bound-to-procedure
    ##sys#signal-hook))

(module blob-hexadecimal

(;export
  blob->hex)

(import scheme
  (chicken base)
  (chicken fixnum)
  (chicken blob)
  (chicken foreign)
  (chicken type)
  (only to-hex blob_to_hex)
  (only type-checks check-natural-fixnum check-blob))

;;

(: blob->hex (blob #!optional fixnum (or fixnum boolean) -> string))
;
(define (blob->hex blb #!optional (start 0) (end #f))
  (check-blob 'blob->hex blb)
  (check-natural-fixnum 'blob->hex start 'start)
  (when end (check-natural-fixnum 'blob->hex end 'end))
  (let ((end (or end (blob-size blb))))
    (unless (fx<= start end)
      (##sys#signal-hook
        #:bounds-error 'blob->hex "illegal subvector specification" start end))
    (let ((len (fx- end start)))
      (if (fx= 0 len)
        ""
        (let ((res (make-string (fx* len 2))))
          (blob_to_hex res blb start len)
          res ) ) ) ) )

) ;module blob-hexadecimal