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;;; binary-ports.scm --- Binary IO on ports
;;; Copyright (C) 2009-2011,2013,2016,2019,2021,2023,2024 Free Software Foundation, Inc.
;;;
;;; This library is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU Lesser General Public License as
;;; published by the Free Software Foundation, either version 3 of the
;;; License, or (at your option) any later version.
;;;
;;; This library is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;; Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public
;;; License along with this program. If not, see
;;; <http://www.gnu.org/licenses/>.
;;; Author: Ludovic Courtès <[email protected]>
;;; Commentary:
;;;
;;; The I/O port API of the R6RS is provided by this module. In many areas
;;; it complements or refines Guile's own historical port API. For instance,
;;; it allows for binary I/O with bytevectors.
;;;
;;; Code:
(define-module (ice-9 binary-ports)
#:use-module (rnrs bytevectors)
#:autoload (rnrs bytevectors gnu) (bytevector-slice)
#:use-module (ice-9 match)
#:use-module (ice-9 custom-ports)
#:export (eof-object
open-bytevector-input-port
open-bytevector-output-port
get-u8
lookahead-u8
get-bytevector-n
get-bytevector-n!
get-bytevector-some
get-bytevector-some! ; Guile extension, not in R6RS
get-bytevector-all
get-string-n!
put-u8
put-bytevector
unget-bytevector
make-custom-binary-input-port
make-custom-binary-output-port
make-custom-binary-input/output-port
call-with-input-bytevector
call-with-output-bytevector))
;; Note that this extension also defines %make-transcoded-port, which is
;; not exported but is used by (rnrs io ports).
(load-extension (string-append "libguile-" (effective-version))
"scm_init_r6rs_ports")
(define (call-with-input-bytevector bv proc)
"Call the one-argument procedure @var{proc} with a newly created
binary input port from which the bytevector @var{bv}'s contents may be
read. All values yielded by @var{proc} are returned."
(proc (open-bytevector-input-port bv)))
(define (call-with-output-bytevector proc)
"Call the one-argument procedure @var{proc} with a newly created
binary output port. When the function returns, port is closed and the
bytevector composed of the bytes written into the port is returned."
(call-with-values
(lambda ()
(open-bytevector-output-port))
(lambda (port get-bytevector)
(proc port)
(let ((bv (get-bytevector)))
(close-port port)
bv))))
(define (type-error proc expecting val)
(scm-error 'wrong-type-arg proc "Wrong type (expecting `~S'): ~S"
(list expecting val) (list val)))
(define (custom-binary-port-read read)
(unless (procedure? read)
(type-error "custom-binary-port-read" "procedure" read))
(lambda (port bv start count)
(let ((ret (read bv start count)))
(unless (and (exact-integer? ret) (<= 0 ret count))
(scm-error 'out-of-range "custom-binary-port-read"
"Value out of range: ~S" (list ret) (list ret)))
ret)))
(define (custom-binary-port-write write)
(unless (procedure? write)
(type-error "custom-binary-port-write" "procedure" write))
(lambda (port bv start count)
(let ((ret (write bv start count)))
(unless (and (exact-integer? ret) (<= 0 ret count))
(scm-error 'out-of-range "custom-binary-port-write"
"Value out of range: ~S" (list ret) (list ret)))
ret)))
(define (custom-binary-port-seek get-position set-position!)
(when get-position
(unless (procedure? get-position)
(type-error "custom-binary-port-seek" "procedure" get-position)))
(when set-position!
(unless (procedure? set-position!)
(type-error "custom-binary-port-seek" "procedure" set-position!)))
(define (seek port offset whence)
(cond
((eqv? whence SEEK_CUR)
(unless get-position
(type-error "custom-binary-port-seek"
"R6RS custom binary port with `port-position` support"
port))
(if (zero? offset)
(get-position)
(seek port (+ (get-position) offset) SEEK_SET)))
((eqv? whence SEEK_SET)
(unless set-position!
(type-error "custom-binary-port-seek"
"Seekable R6RS custom binary port"
port))
(set-position! offset)
;; Assume setting the position succeeds.
offset)
((eqv? whence SEEK_END)
(error "R6RS custom binary ports do not support `SEEK_END'"))))
seek)
(define (custom-binary-port-close close)
(match close
(#f (lambda (port) #t))
((? procedure?) (lambda (port) (close)))
(_ (type-error "custom-binary-port-close" "procedure" close))))
(define (custom-binary-port-random-access? set-position!)
(if set-position!
(lambda (port) #t)
(lambda (port) #f)))
(define (make-custom-binary-input-port id read get-position set-position! close)
(unless (string? id)
(type-error "make-custom-binary-input-port" "string" id))
(make-custom-port #:id id
#:read (custom-binary-port-read read)
#:seek (custom-binary-port-seek get-position set-position!)
#:close (custom-binary-port-close close)
#:random-access?
(custom-binary-port-random-access? set-position!)
;; FIXME: Instead default to current encoding, if
;; someone reads text from this port.
#:encoding 'ISO-8859-1 #:conversion-strategy 'error))
(define (make-custom-binary-output-port id write get-position set-position!
close)
(unless (string? id)
(type-error "make-custom-binary-output-port" "string" id))
(make-custom-port #:id id
#:write (custom-binary-port-write write)
#:seek (custom-binary-port-seek get-position set-position!)
#:close (custom-binary-port-close close)
#:random-access?
(custom-binary-port-random-access? set-position!)
;; FIXME: Instead default to current encoding, if
;; someone reads text from this port.
#:encoding 'ISO-8859-1 #:conversion-strategy 'error))
(define (make-custom-binary-input/output-port id read write get-position
set-position! close)
(unless (string? id)
(type-error "make-custom-binary-input/output-port" "string" id))
(make-custom-port #:id id
#:read (custom-binary-port-read read)
#:write (custom-binary-port-write write)
#:seek (custom-binary-port-seek get-position set-position!)
#:close (custom-binary-port-close close)
#:random-access?
(custom-binary-port-random-access? set-position!)
;; FIXME: Instead default to current encoding, if
;; someone reads text from this port.
#:encoding 'ISO-8859-1 #:conversion-strategy 'error))
;;;
;;; Binary input.
;;;
(define (get-bytevector-all port)
"Read from @var{port}, blocking as necessary, until
the end-of-file is reached. Return either a new bytevector containing
the data read or the end-of-file object (if no data were available)."
(define initial-capacity 4096)
(let loop ((bv (make-bytevector initial-capacity))
(capacity initial-capacity)
(size 0))
(match (get-bytevector-n! port bv size (- capacity size))
((? eof-object?)
(bytevector-slice bv 0 size))
(read
(let ((size (+ read size)))
(if (= capacity size)
(let* ((capacity (* capacity 2))
(new (make-bytevector capacity)))
(bytevector-copy! bv 0 new 0 size)
(loop new capacity size))
(loop bv capacity size)))))))
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