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c1b7fea8f9
Estimated hours taken: 0.25 Branches: main NEWS: library/io.m: compiler/bytecode_data.m: Mark io.write_bytes as obsolete, because strings are a poor choice of representation for binary data. Use bitmaps and io.write_bitmap instead.
280 lines
8.8 KiB
Mathematica
280 lines
8.8 KiB
Mathematica
%-----------------------------------------------------------------------------%
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% vim: ft=mercury ts=4 sw=4 et
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%---------------------------------------------------------------------------%
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% Copyright (C) 1999-2000, 2003-2007 The University of Melbourne.
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% This file may only be copied under the terms of the GNU General
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% Public License - see the file COPYING in the Mercury distribution.
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%---------------------------------------------------------------------------%
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%
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% File: bytecode_data.m.
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% Authors: zs, aet, stayl.
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%
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% This module defines the representation of basic types used by the bytecode
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% interpreter.
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%
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%---------------------------------------------------------------------------%
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:- module backend_libs.bytecode_data.
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:- interface.
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:- import_module io.
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:- import_module list.
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%---------------------------------------------------------------------------%
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% XXX this assumes strings contain 8-bit characters
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:- pred output_string(string::in, io::di, io::uo) is det.
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:- pred string_to_byte_list(string::in, list(int)::out) is det.
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:- pred output_byte(int::in, io::di, io::uo) is det.
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% Spit out an `int' in a portable `highest common denominator' format.
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% This format is: big-endian, 64-bit, 2's-complement int.
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%
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% NOTE: We -assume- the machine architecture uses 2's-complement.
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%
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:- pred output_int(int::in, io::di, io::uo) is det.
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:- pred int_to_byte_list(int::in, list(int)::out) is det.
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% Same as output_int and int_to_byte_list, except only use 32 bits.
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%
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:- pred output_int32(int::in, io::di, io::uo) is det.
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:- pred int32_to_byte_list(int::in, list(int)::out) is det.
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% Spit out a `short' in a portable format.
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% This format is: big-endian, 16-bit, 2's-complement.
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%
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% NOTE: We -assume- the machine architecture uses 2's-complement.
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%
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:- pred output_short(int::in, io::di, io::uo) is det.
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:- pred short_to_byte_list(int::in, list(int)::out) is det.
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% Spit out a `float' in a portable `highest common denominator format.
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% This format is: big-endian, 64-bit, IEEE-754 floating point value.
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%
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% NOTE: We -assume- the machine architecture uses IEEE-754.
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%
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:- pred output_float(float::in, io::di, io::uo) is det.
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:- pred float_to_byte_list(float::in, list(int)::out) is det.
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%-----------------------------------------------------------------------------%
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%-----------------------------------------------------------------------------%
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:- implementation.
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:- import_module libs.
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:- import_module libs.compiler_util.
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:- import_module char.
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:- import_module int.
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:- import_module string.
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%-----------------------------------------------------------------------------%
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output_string(Val, !IO) :-
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string_to_byte_list(Val, List),
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list.foldl(io.write_byte, List, !IO),
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io.write_byte(0, !IO).
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string_to_byte_list(Val, List) :-
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% XXX this assumes strings contain 8-bit characters
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% Using char.to_int here is wrong; the output will depend
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% on the Mercury implementation's representation of chars,
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% so it may be different for different Mercury implementations.
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% In particular, it will do the wrong thing for Mercury
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% implementations which represent characters in Unicode.
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string.to_char_list(Val, Chars),
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ToInt = (pred(C::in, I::out) is det :- char.to_int(C, I)),
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list.map(ToInt, Chars, List0),
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list.append(List0, [0], List).
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output_byte(Val, !IO) :-
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( Val < 256 ->
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io.write_byte(Val, !IO)
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;
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unexpected(this_file, "output_byte: byte does not fit in eight bits")
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).
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output_short(Val, !IO) :-
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output_int(16, Val, !IO).
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short_to_byte_list(Val, Bytes) :-
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int_to_byte_list(16, Val, Bytes).
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output_int32(IntVal, !IO) :-
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output_int(32, IntVal, !IO).
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int32_to_byte_list(IntVal, List) :-
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int_to_byte_list(32, IntVal, List).
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output_int(IntVal, !IO) :-
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int.bits_per_int(IntBits),
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( IntBits > bytecode_int_bits ->
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unexpected(this_file, "output_int: " ++
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"size of int is larger than size of bytecode integer.")
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;
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output_int(bytecode_int_bits, IntVal, !IO)
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).
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int_to_byte_list(IntVal, Bytes) :-
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int.bits_per_int(IntBits),
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( IntBits > bytecode_int_bits ->
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unexpected(this_file, "int_to_byte_list: " ++
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"size of int is larger than size of bytecode integer.")
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;
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int_to_byte_list(bytecode_int_bits, IntVal, Bytes)
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).
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:- pred output_int(int::in, int::in, io::di, io::uo) is det.
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output_int(Bits, IntVal, !IO) :-
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output_int(io.write_byte, Bits, IntVal, !IO).
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:- pred int_to_byte_list(int::in, int::in, list(int)::out) is det.
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int_to_byte_list(Bits, IntVal, Bytes) :-
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output_int(list.cons, Bits, IntVal, [], RevBytes),
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list.reverse(RevBytes, Bytes).
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:- pred output_int(pred(int, T, T), int, int, T, T).
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:- mode output_int(pred(in, in, out) is det, in, in, in, out) is det.
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:- mode output_int(pred(in, di, uo) is det, in, in, di, uo) is det.
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output_int(Writer, Bits, IntVal, !IO) :-
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int.bits_per_int(IntBits),
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(
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Bits < IntBits,
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int.pow(2, Bits - 1, MaxVal),
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( IntVal >= MaxVal
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; IntVal < -MaxVal
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)
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->
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string.format(
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"error: bytecode_data.output_int: " ++
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"%d does not fit in %d bits",
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[i(IntVal), i(Bits)], Msg),
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unexpected(this_file, Msg)
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;
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true
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),
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( Bits > IntBits ->
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ZeroPadBytes = (Bits - IntBits) // bits_per_byte
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;
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ZeroPadBytes = 0
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),
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output_padding_zeros(Writer, ZeroPadBytes, !IO),
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BytesToDump = Bits // bits_per_byte,
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FirstByteToDump = BytesToDump - ZeroPadBytes - 1,
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output_int_bytes(Writer, FirstByteToDump, IntVal, !IO).
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:- func bytecode_int_bits = int.
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bytecode_int_bits = bits_per_byte * bytecode_int_bytes.
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:- func bytecode_int_bytes = int.
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bytecode_int_bytes = 8.
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:- func bits_per_byte = int.
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bits_per_byte = 8.
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:- pred output_padding_zeros(pred(int, T, T), int, T, T).
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:- mode output_padding_zeros(pred(in, in, out) is det, in, in, out) is det.
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:- mode output_padding_zeros(pred(in, di, uo) is det, in, di, uo) is det.
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output_padding_zeros(Writer, NumBytes, !IO) :-
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( NumBytes > 0 ->
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call(Writer, 0, !IO),
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NumBytes1 = NumBytes - 1,
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output_padding_zeros(Writer, NumBytes1, !IO)
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;
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true
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).
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:- pred output_int_bytes(pred(int, T, T), int, int, T, T).
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:- mode output_int_bytes(pred(in, in, out) is det, in, in, in, out) is det.
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:- mode output_int_bytes(pred(in, di, uo) is det, in, in, di, uo) is det.
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output_int_bytes(Writer, ByteNum, IntVal, !IO) :-
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( ByteNum >= 0 ->
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BitShifts = ByteNum * bits_per_byte,
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Byte = (IntVal >> BitShifts) mod (1 << bits_per_byte),
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ByteNum1 = ByteNum - 1,
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call(Writer, Byte, !IO),
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output_int_bytes(Writer, ByteNum1, IntVal, !IO)
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;
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true
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).
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output_float(Val, !IO) :-
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float_to_float64_bytes(Val, B0, B1, B2, B3, B4, B5, B6, B7),
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output_byte(B0, !IO),
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output_byte(B1, !IO),
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output_byte(B2, !IO),
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output_byte(B3, !IO),
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output_byte(B4, !IO),
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output_byte(B5, !IO),
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output_byte(B6, !IO),
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output_byte(B7, !IO).
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float_to_byte_list(Val, [B0, B1, B2, B3, B4, B5, B6, B7]) :-
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float_to_float64_bytes(Val, B0, B1, B2, B3, B4, B5, B6, B7).
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% Convert a `float' to the representation used in the bytecode.
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% That is, a sequence of eight bytes.
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%
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:- pred float_to_float64_bytes(float::in,
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int::out, int::out, int::out, int::out,
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int::out, int::out, int::out, int::out) is det.
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:- pragma foreign_proc("C",
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float_to_float64_bytes(FloatVal::in, B0::out, B1::out, B2::out,
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B3::out, B4::out, B5::out, B6::out, B7::out),
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[promise_pure, will_not_call_mercury],
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"
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{
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MR_Float64 float64;
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unsigned char *raw_mem_p;
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float64 = (MR_Float64) FloatVal;
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raw_mem_p = (unsigned char *) &float64;
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#if defined(MR_BIG_ENDIAN)
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B0 = raw_mem_p[0];
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B1 = raw_mem_p[1];
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B2 = raw_mem_p[2];
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B3 = raw_mem_p[3];
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B4 = raw_mem_p[4];
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B5 = raw_mem_p[5];
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B6 = raw_mem_p[6];
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B7 = raw_mem_p[7];
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#elif defined(MR_LITTLE_ENDIAN)
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B7 = raw_mem_p[0];
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B6 = raw_mem_p[1];
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B5 = raw_mem_p[2];
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B4 = raw_mem_p[3];
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B3 = raw_mem_p[4];
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B2 = raw_mem_p[5];
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B1 = raw_mem_p[6];
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B0 = raw_mem_p[7];
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#else
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#error ""Weird-endian architecture""
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#endif
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}
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").
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float_to_float64_bytes(_FloatVal, _B0, _B1, _B2, _B3, _B4, _B5, _B6, _B7) :-
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sorry(this_file, "float_to_float64_bytes for non-C target").
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%---------------------------------------------------------------------------%
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:- func this_file = string.
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this_file = "bytecode_data.m".
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%---------------------------------------------------------------------------%
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:- end_module bytecode_data.
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%---------------------------------------------------------------------------%
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