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== bvconv
[[toc:]]

=== Description
'''bvconv''' is CHICKEN6  iconv (man 3 iconv) glibc 'adapter'. Actually bvconv similar to '''iconv''' CHICKEN5 Egg. On bytevectors, or utf8 strings in R7RS manner.
And args FROM and TO was swapped.

=== Authors
[[e-mail-to:corbas.ai@gmail.com|Anton Idukov]]

=== Repository
Sorces hosted on Codeberg https://codeberg.org/Corbas/bvconv

=== Requirements
Just glibc or (unproven) musl.

=== API

==== make-conv
<procedure>(make-conv FROMENC TOENC)</procedure>

To make converter closure use '''make-conv''' procedure with positional
args FROMENC - string - encoding name for example "ISO_8859-1"  and
TOENC - maybe "UTF-8". The list of available encodings we get by shell command '''iconv --list'''

==== make-conv*
<procedure>(make-conv* #!keyword from to)</procedure>

Same as '''make-conv''' but with keyword args '''#:from'''  and '''#:to'''

=== Example
<enscript highlight="scheme">

(import bvconv)

;; From String source we've got String result:
(let* ((t "Hello")
       (cv (make-conv "ASCII" "UTF-8"))
       (converted (cv t)))
    (display (list converted "string?" (string? converted)))
    (newline))

==> (Hello string? #t)

;; From Bytevector source we've got Bytevector result:
(let ((v ((make-conv "L1" "UTF-8") #u8("Hello"))))
  (display (list v " bytevector? " (bytevector? v)))
  (newline))

==> (#u8(72 101 108 108 111) bytevector? #t)

;; We can make reverser closure from converter closure
(let* ((cv (make-conv "ASCII" "EBCDICUS"))
       (vc (cv'reverse))
       (t #u8("Hello")))
  (display (list t "->"
            (cv t) "->"
            (vc (cv t)) ":"
            (utf8->string (vc (cv t)))))
  (newline))

==> (#u8(72 101 108 108 111) -> #u8(200 133 147 147 150) -> #u8(72 101 108 108 111) : Hello)

;; We can catch iconv error conditions by special second param to converter closure
;; (: err (bytevector fixnum fixnum -> void))

(define (err src pos errno) (raise `(bvconv-error ,errno ,pos)))

(guard
    (ex
     ((and (pair? ex) (eq? (car ex) 'bvconv-error) (number? (cadr ex)))
      (display
       (string-append "!Error: "
                      (let ((errno (cadr ex)))
                        (cond ((= errno EINVAL) "invalid value")
                              ((= errno E2BIG) "source converts into bit bigger than destination")
                              ((= errno EILSEQ) "wrong source char sequence")
                              ((= error EBADF) "bad file" )
                              (else "wrong answer on a bad question!")))
                      "\n")))
     (#t (display ex) (newline)))
  (let ((cv (make-conv "ASCII" "UTF8")))
    (cv "СОЛНЦЕ" err)))

==> !Error: wrong source char sequence
</enscript>

=== Source code
[[https://codeberg.org/Corbas/bvconv|bvconv at Codeberg]]

=== Licence
BSD-2-Clause licence.

=== Version History
1.0.2 Initial release

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