--- /dev/null
+#!/usr/bin/guile --no-auto-compile
+-*- scheme -*-
+!#
+
+;;; srt2vtt --- SRT to WebVTT converter
+;;; Copyright © 2015 David Thompson <davet@gnu.org>
+;;;
+;;; srt2vtt is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; srt2vtt 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
+;;; General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with Haunt. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; Convert SRT formatted subtitles to WebVTT format.
+;;
+;;; Code:
+
+(use-modules (ice-9 format)
+ (ice-9 match)
+ (ice-9 rdelim)
+ (ice-9 regex)
+ (srfi srfi-1)
+ (srfi srfi-9)
+ (srfi srfi-11)
+ (srfi srfi-26)
+ (srfi srfi-37))
+
+(define-record-type <subtitle>
+ (make-subtitle id start end text)
+ subtitle?
+ (id subtitle-id)
+ (start subtitle-start)
+ (end subtitle-end)
+ (text subtitle-text))
+
+(define parse-time
+ (let ((regexp (make-regexp "([0-9]+):([0-9]+):([0-9]+),([0-9]+)")))
+ (lambda (s)
+ (let ((match (regexp-exec regexp s)))
+ (map (cut match:substring match <>) '(1 2 3 4))))))
+
+(define parse-time-span
+ (let ((regexp (make-regexp "([0-9:,]+) --> ([0-9:,]+)")))
+ (lambda (s)
+ (let ((match (regexp-exec regexp s)))
+ (values (parse-time (match:substring match 1))
+ (parse-time (match:substring match 2)))))))
+
+(define (read-sub-rip port)
+ (let-values (((id) (string->number (read-line port)))
+ ((start end) (parse-time-span (read-line port)))
+ ((lines) (let loop ((lines '()))
+ (let ((line (read-line port)))
+ (if (string-null? line)
+ lines
+ (loop (cons line lines)))))))
+ (make-subtitle id start end lines)))
+
+(define (read-sub-rips port)
+ (reverse
+ (let loop ((subs '()))
+ (if (eof-object? (peek-char port))
+ subs
+ (loop (cons (read-sub-rip port) subs))))))
+
+(define (write-time time port)
+ (match time
+ ((h m s ms)
+ (format port "~a:~a:~a.~a" h m s ms))))
+
+(define (write-web-vtt subtitle port)
+ (match subtitle
+ (($ <subtitle> id start end text)
+ (format port "~a~%" id)
+ (write-time start port)
+ (display " --> " port)
+ (write-time end port)
+ (newline port)
+ (format port "~a~%" (string-join text "\n"))
+ (newline port))))
+
+(define (write-web-vtts subtitles port)
+ (display "WEBVTT\n" port)
+ (for-each (cut write-web-vtt <> port) subtitles))
+
+(define (convert input-port output-port)
+ (write-web-vtts (read-sub-rips input-port) output-port))
+
+(define (show-help-and-exit)
+ (format #t "Usage: srt2vtt [OPTIONS]
+Convert SubRip formatted subtitles to WebVTT format.~%")
+ (display "
+ -h, --help display this help and exit")
+ (display "
+ -v, --version display version and exit")
+ (display "
+ -i, --input=FILE-NAME read input from FILE-NAME")
+ (display "
+ -o, --output=FILE-NAME write output to FILE-NAME")
+ (newline)
+ (exit 0))
+
+(define (show-version-and-exit)
+ (format #t "srt2vtt 0.1~%")
+ (exit 0))
+
+(define (show-usage-and-exit)
+ (format #t "Try `srt2vtt --help' for more information.~%")
+ (exit 1))
+
+(define (show-wrong-args-and-exit)
+ (format #t "Invalid arguments~%")
+ (show-usage-and-exit))
+
+(define %default-args
+ `((input . ,(current-input-port))
+ (output . ,(current-output-port))))
+
+(define %options
+ (list (option '(#\h "help") #f #f
+ (lambda (opt name arg args)
+ (show-help-and-exit)))
+ (option '(#\v "version") #f #f
+ (lambda (opt name arg args)
+ (show-version-and-exit)))
+ (option '(#\i "input") #t #f
+ (lambda (opt name arg args)
+ (alist-cons 'input arg args)))
+ (option '(#\o "output") #t #f
+ (lambda (opt name arg args)
+ (alist-cons 'output arg args)))))
+
+(define (make-call-with-port-or-file file-proc)
+ (lambda (port-or-file proc)
+ (if (port? port-or-file)
+ (proc port-or-file)
+ (file-proc port-or-file proc))))
+
+(define call-with-port-or-input-file
+ (make-call-with-port-or-file call-with-input-file))
+
+(define call-with-port-or-output-file
+ (make-call-with-port-or-file call-with-output-file))
+
+(define (parse-opts args)
+ (args-fold args
+ %options
+ (lambda (opt name arg args)
+ (error "Unrecognized option '~a'" name))
+ (lambda (arg args)
+ (error "Extraneous argument '~a'" arg))
+ %default-args))
+
+(define (main args)
+ (let ((opts (parse-opts args)))
+ (call-with-port-or-input-file (assoc-ref opts 'input)
+ (lambda (input-port)
+ (call-with-port-or-output-file (assoc-ref opts 'output)
+ (lambda (output-port)
+ (convert input-port output-port)))))))
+
+(match (command-line)
+ ((arg0 args ...)
+ (main args)))
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