1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker 4 E-mail: J.Wielemaker@vu.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (c) 2006-2016, University of Amsterdam 7 VU University Amsterdam 8 All rights reserved. 9 10 Redistribution and use in source and binary forms, with or without 11 modification, are permitted provided that the following conditions 12 are met: 13 14 1. Redistributions of source code must retain the above copyright 15 notice, this list of conditions and the following disclaimer. 16 17 2. Redistributions in binary form must reproduce the above copyright 18 notice, this list of conditions and the following disclaimer in 19 the documentation and/or other materials provided with the 20 distribution. 21 22 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 25 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 26 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 27 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 28 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 30 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 32 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 POSSIBILITY OF SUCH DAMAGE. 34*/ 35 36:- module(zlib, 37 [ zopen/3, % +Stream, -ZStream, +Option 38 gzopen/3, % +File, +Mode, -Stream 39 gzopen/4 % +File, +Mode, -Stream, +Options 40 ]). 41:- autoload(library(apply),[partition/4]). 42:- autoload(library(error),[must_be/2]). 43:- autoload(library(option),[merge_options/3,option/2]). 44 45:- predicate_options(zopen/3, 3, 46 [ format(oneof([gzip,deflate,raw_deflate])), 47 multi_part(boolean), 48 close_parent(boolean), 49 level(between(0,9)) 50 ]). 51:- predicate_options(gzopen/4, 4, 52 [ pass_to(zopen/3, 3), 53 pass_to(system:open/4, 4) 54 ]). 55 56/** <module> Zlib wrapper for SWI-Prolog 57 58Read/write compressed data based on the zlib library. 59 60@author Jan Wielemaker 61@see http://www.zlib.net/ 62@see http://www.swi-prolog.org/packages/zlib.html 63*/ 64 65:- use_foreign_library(foreign(zlib4pl)). 66:- public zdebug/1. % Set debug level 67 68%! gzopen(+File, +Mode, -Stream) is det. 69%! gzopen(+File, +Mode, -Stream, +Options) is det. 70% 71% Open a file compatible with the gzip program. Note that if a 72% file is opened in =append= mode, a second gzip image will be 73% added to the end of the file. The gzip standard defines that a 74% file can hold multiple gzip images and inflating the file 75% results in a concatenated stream of all inflated images. 76% 77% Options are passed to open/4 and zopen/3. Default format is 78% =gzip=. 79 80gzopen(File, Mode, Stream) :- 81 gzopen(File, Mode, Stream, []). 82 83gzopen(File, Mode, Stream, Options) :- 84 must_be(oneof([read,write,append]), Mode), 85 partition(zoption, Options, ZOptions0, OpenOptions), 86 merge_options(ZOptions0, 87 [ format(gzip), 88 close_parent(true) 89 ], ZOptions), 90 open(File, Mode, Stream0, OpenOptions), 91 zopen(Stream0, Stream, ZOptions), 92 set_stream(Stream, file_name(File)), 93 ( option(alias(Alias), ZOptions) 94 -> set_stream(Stream, alias(Alias)) 95 ; true 96 ). 97 98 99zoption(format(_)). 100zoption(multi_part(_)). 101zoption(level(_)). 102zoption(alias(_)). 103 104%! http:encoding_filter(+Encoding, +In0, -In) is semidet. 105% 106% Act as plugin for library(http/http_open) for processing content 107% with =|Content-encoding: gzip|= 108 109httpencoding_filter(gzip, In0, In) :- 110 zopen(In0, In, 111 [ close_parent(true) 112 ])