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) 2010-2021, VU University Amsterdam 7 SWI-Prolog Solutions b.v. 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(fastrw, 37 [ fast_read/1, % -Term 38 fast_write/1, % +Term 39 fast_read/2, % +Stream, -Term 40 fast_write/2, % +Stream, +Term 41 fast_write_to_string/3 % +Term, -String, ?Tail 42 ]). 43:- autoload(library(lists),[append/3]).
87fast_read(Term) :- 88 fast_read(current_input, Term).
95fast_write(Term) :- 96 fast_write(current_output, Term).
102fast_write_to_string(T, S, R) :- 103 fast_term_serialized(T, String), 104 string_codes(String, Codes), 105 append(Codes, R, S)
Fast reading and writing of terms
This library provides the SICStus and Ciao library(fastrw) interface. The idea behind this library is to design a fast serialization for Prolog terms. Ideally, this should be portable between Prolog implementation. Unfortunately there is no portably binary term format defined.
The current implementation is based on PL_record_external(), which provides a binary representation of terms that is processed efficiently and can handle subterm sharing, cycles and attributed variables. In other words, this library can handle any Prolog term except blobs such as stream handles, database references, etc. We try to keep the format compatible between versions, but this is not guaranteed. Conversion is always possible by reading a database using the old version, dump it using write_canonical/1 and read it into the new version.
This library is built upon the following built in predicates: