/* Part of SWI-Prolog
Author: Jan Wielemaker
Copyright (c) 2010-2016, VU University Amsterdam
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[ fast_read/1, % -Term
fast_write/1, % +Term
fast_read/2, % +Stream, -Term
fast_write/2, % +Stream, +Term
fast_write_to_string/3 % +Term, -String, ?Tail
/** <module> 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
The current implementation is based on PL_record_external(), which
provides a binary representation of terms that is processed efficiently
and can handle cycles as well as attributes. 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:
- fast_term_serialized/2 translates between a term and its
serialization as a byte string.
- fast_read/2 and fast_write/2 read/write binary serializations.
@tbd Establish a portable binary format.
@compat The format is not compatible to SICStus/Ciao (which are not
compatible either). Funture versions of this library might
implement a different encoding.
@bug The current implementation of fast_read/1 *is not safe*.
It is guaranteed to safely read terms written using
fast_write/1, but may crash on arbitrary input. The
implementation does perform some basic sanity checks,
including validation of the magic start byte.
% The next term is read from current standard input and is unified
% with Term. The syntax of the term must agree with fast_read /
% fast_write format. If the end of the input has been reached,
% Term is unified with the term =end_of_file=.
% Output Term in a way that fast_read/1 and fast_read/2 will be
% able to read it back.
%! fast_write_to_string(+Term, -String, ?Tail)
% Perform a fast-write to the difference-slist String\Tail.
fast_write_to_string(T, S, R) :-
append(Codes, R, S).