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Add phrase_from_stream/2 to library(pio)

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bakaq
2023-09-21 21:06:02 -03:00
parent 75dcc3f276
commit 35d0042be1
1 changed files with 154 additions and 16 deletions
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156
src/lib/pio.pl
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@@ -9,6 +9,7 @@
:- module(pio, [phrase_from_file/2,
phrase_from_file/3,
phrase_from_stream/2,
phrase_to_file/2,
phrase_to_file/3,
phrase_to_stream/2
@@ -17,16 +18,30 @@
:- use_module(library(dcgs)).
:- use_module(library(error)).
:- use_module(library(freeze)).
:- use_module(library(iso_ext), [setup_call_cleanup/3, partial_string/3]).
:- use_module(library(lists), [member/2, maplist/2]).
:- use_module(library(gensym)).
:- use_module(library(iso_ext), [
bb_get/2, bb_put/2, setup_call_cleanup/3, partial_string/3, partial_string_tail/2
]).
:- use_module(library(lists), [length/2, member/2, maplist/2]).
:- use_module(library(charsio), [get_n_chars/3]).
:- meta_predicate(phrase_from_file(2, ?)).
:- meta_predicate(phrase_from_file(2, ?, ?)).
:- meta_predicate(phrase_from_stream(2, ?)).
:- meta_predicate(phrase_to_file(2, ?)).
:- meta_predicate(phrase_to_file(2, ?, ?)).
:- meta_predicate(phrase_to_stream(2, ?)).
%% phrase_from_stream(+GRBody, +Stream)
%
% True if grammar rule body GRBody covers the contents of the stream,
% represented as a list of characters.
phrase_from_stream(GRBody, Stream) :-
stream_to_lazy_list(Stream, Ls),
phrase(GRBody, Ls).
%% phrase_from_file(+GRBody, +File)
%
% True if grammar rule body GRBody covers the contents of File,
@@ -49,23 +64,146 @@ phrase_from_file(NT, File, Options) :-
; Type = text
),
setup_call_cleanup(open(File, read, Stream, [reposition(true)|Options]),
( stream_to_lazy_list(Stream, Xs),
phrase(NT, Xs) ),
phrase_from_stream(NT, Stream),
close(Stream))
).
stream_to_lazy_list(Stream, Xs) :-
stream_property(Stream, position(Pos)),
freeze(Xs, reader_step(Stream, Pos, Xs)).
stream_property(Stream, reposition(Rep)),
( Rep = true ->
stream_to_lazy_list_repositionable(Stream, Xs)
; stream_to_lazy_list_buffer(Stream, Xs)
).
reader_step(Stream, Pos, Xs0) :-
stream_to_lazy_list_repositionable(Stream, Xs) :-
stream_property(Stream, position(Pos)),
freeze(Xs, reader_step_repositionable(Stream, Pos, Xs)).
reader_step_repositionable(Stream, Pos, Xs0) :-
set_stream_position(Stream, Pos),
( at_end_of_stream(Stream)
-> Xs0 = []
; get_n_chars(Stream, 4096, Cs),
partial_string(Cs, Xs0, Xs),
stream_to_lazy_list(Stream, Xs)
stream_to_lazy_list_repositionable(Stream, Xs)
).
stream_to_lazy_list_buffer(Stream, Ls) :-
get_stream_buffer_position(Stream, Pos),
freeze(Ls, render_step_buffer(Stream, Pos, Ls)).
render_step_buffer(Stream, Pos, Ls) :-
set_stream_buffer_position(Stream, Pos),
( buffer_at_end_of_stream(Stream) ->
Ls = []
; buffer_get_n_chars(Stream, 4096, Chars),
partial_string(Chars, Ls, Ls0),
stream_to_lazy_list_buffer(Stream, Ls0)
).
buffer_at_end_of_stream(Stream) :-
stream_bufferids(Stream, _, BufferPosId, _),
bb_get(BufferPosId, Pos),
Pos = eof.
get_stream_buffer_position(Stream, Pos) :-
stream_bufferids(Stream, _, BufferPosId, _),
bb_get(BufferPosId, Pos).
set_stream_buffer_position(Stream, Pos) :-
stream_bufferids(Stream, _, BufferPosId, _),
bb_put(BufferPosId, Pos).
buffer_get_n_chars(Stream, N, Chars) :-
stream_bufferids(Stream, BufferId, BufferPosId, BufferLenId),
buffer_prepare_for_n(Stream, BufferId, BufferPosId, BufferLenId, N),
bb_get(BufferId, Buffer),
bb_get(BufferPosId, BufferPos),
( BufferPos = eof ->
Chars = []
; string_get_n_chars(Buffer, BufferPos, N, Chars),
length(Chars, NChars),
( NChars = 0 ->
BufferPos1 = eof
; BufferPos1 is BufferPos + NChars
),
bb_put(BufferPosId, BufferPos1)
).
buffer_prepare_for_n(Stream, BufferId, BufferPosId, BufferLenId, N) :-
bb_get(BufferPosId, BufferPos),
bb_get(BufferLenId, BufferLen),
( BufferLen < BufferPos + N ->
bb_get(BufferId, Buffer),
(
( var(Buffer) ->
BufferTail = Buffer
; partial_string_last_tail(Buffer, BufferTail)
) ->
( at_end_of_stream(Stream) ->
BufferTail = [],
bb_put(BufferId, Buffer)
; get_n_chars(Stream, 4096, Chars),
length(Chars, NChars),
partial_string(Chars, BufferTail, _),
bb_put(BufferId, Buffer),
BufferLen1 is BufferLen + NChars,
bb_put(BufferLenId, BufferLen1),
buffer_prepare_for_n(Stream, BufferId, BufferPosId, BufferLenId, N)
)
; true
)
; true
).
partial_string_last_tail(PartialString, PartialStringTail) :-
partial_string_tail(PartialString, PartialStringTail0),
( var(PartialStringTail0) ->
PartialStringTail = PartialStringTail0
; partial_string_last_tail(PartialStringTail0, PartialStringTail)
).
string_get_n_chars([], _, _, []).
string_get_n_chars([S|Ss], BufferPos, N, Chars) :-
( BufferPos = 0 ->
string_get_n_chars_([S|Ss], N, Chars)
; BufferPos1 is BufferPos - 1,
string_get_n_chars(Ss, BufferPos1, N, Chars)
).
string_get_n_chars_([], _, []).
string_get_n_chars_([S|Ss], N, Chars) :-
( N = 0 ->
Chars = []
; N = 1 ->
% This case is needed to not break the tail of the partial string
Chars = [S]
; Chars = [S|Cs],
N1 is N - 1,
string_get_n_chars_(Ss, N1, Cs)
).
stream_bufferids(Stream, BufferId, BufferPosId, BufferLenId) :-
( bb_get(streams_buffers, _) ->
true
; bb_put(streams_buffers, [])
),
bb_get(streams_buffers, StreamsBuffers),
( member(
stream_buffer(Stream, BufferId, BufferPosId, BufferLenId),
StreamsBuffers
) ->
true
; gensym(buffer, BufferId),
gensym(buffer_pos, BufferPosId),
gensym(buffer_len, BufferLenId),
bb_put(
streams_buffers,
[stream_buffer(Stream, BufferId, BufferPosId, BufferLenId)|StreamsBuffers]
),
bb_put(BufferId, _),
bb_put(BufferPosId, 0),
bb_put(BufferLenId, 0)
).
%% phrase_to_stream(+GRBody, +Stream)