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https://github.com/Mercury-Language/mercury.git
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6e91909412
Support direct putback of int8 and uint8 values to binary input streams
instead of via the bottom 8 bits of an int value.
library/io.m:
Add putback_{int8,uint8}/[34].
Add stream type class instances for putback streams binary_input_stream
with int8 and uint8.
tests/hard_coded/Mmakefile:
tests/hard_coded/putback_binary_int8.{m,exp}:
tests/hard_coded/putback_binary_uint8.{m,exp}:
Add tests of the above.
89 lines
2.8 KiB
Mathematica
89 lines
2.8 KiB
Mathematica
%---------------------------------------------------------------------------%
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% vim: ts=4 sw=4 et ft=mercury
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%---------------------------------------------------------------------------%
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%
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% Test putback for int8 values with binary streams.
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%
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%---------------------------------------------------------------------------%
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:- module putback_binary_int8.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is det.
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%---------------------------------------------------------------------------%
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%---------------------------------------------------------------------------%
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:- implementation.
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:- import_module char.
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:- import_module int.
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:- import_module list.
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:- import_module require.
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:- import_module string.
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%---------------------------------------------------------------------------%
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main(!IO) :-
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io.open_binary_input("stream_putback.data", OpenRes, !IO),
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(
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OpenRes = ok(Stream),
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print_position(Stream, !IO), % pos 0
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print_read_byte(Stream, !IO), % pos 1
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print_relseek(Stream, 1, !IO), % pos 2
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print_read_byte(Stream, !IO), % pos 3
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print_putback(Stream, -128i8, !IO), % pos 2
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print_read_byte(Stream, !IO), % -128i8 pos 3
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print_read_byte(Stream, !IO), % 10i8 (\n), pos 4
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print_read_byte(Stream, !IO), % eof, pos 4
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print_putback(Stream, 127i8, !IO), % pos 3
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print_relseek(Stream, -2, !IO), % pos 1; pushback dropped
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print_read_byte(Stream, !IO), % b, pos 2
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io.close_binary_input(Stream, !IO)
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;
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OpenRes = error(Error),
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error(io.error_message(Error))
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).
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:- pred print_read_byte(io.binary_input_stream::in, io::di, io::uo) is det.
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print_read_byte(Stream, !IO) :-
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io.read_binary_int8(Stream, ReadRes, !IO),
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(
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ReadRes = ok(Int8),
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io.write_string("Read: ", !IO),
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io.write_line(Int8, !IO)
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;
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ReadRes = eof,
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io.write_string("Read: eof\n", !IO)
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;
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ReadRes = error(Error),
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error(io.error_message(Error))
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),
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print_position(Stream, !IO).
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:- pred print_putback(io.binary_input_stream::in, int8::in, io::di, io::uo)
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is det.
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print_putback(Stream, Int8, !IO) :-
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io.putback_int8(Stream, Int8, !IO),
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io.write_string("Put back: ", !IO),
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io.write_line(Int8, !IO),
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print_position(Stream, !IO).
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:- pred print_relseek(io.binary_input_stream::in, int::in, io::di, io::uo)
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is det.
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print_relseek(Stream, Offset, !IO) :-
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io.seek_binary_input(Stream, cur, Offset, !IO),
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io.format("Seek: %+d\n", [i(Offset)], !IO),
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print_position(Stream, !IO).
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:- pred print_position(io.binary_input_stream::in, io::di, io::uo) is det.
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print_position(Stream, !IO) :-
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io.binary_input_stream_offset(Stream, Offset, !IO),
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io.format("Position: %d\n\n", [i(Offset)], !IO).
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