Lichen

Annotated lib/libc/io.py

849:81587921b9b4
2018-07-11 Paul Boddie Use the __store_via_object operations to set attributes.
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#!/usr/bin/env python
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"""
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C library input/output.
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Copyright (C) 2016, 2017 Paul Boddie <paul@boddie.org.uk>
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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this program.  If not, see <http://www.gnu.org/licenses/>.
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"""
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from __builtins__.stream import filestream
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from __builtins__.types import check_int, check_string
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import locale
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from native import (
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    close as _close,
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    fdopen as _fdopen,
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    read as _read,
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    write as _write
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    )
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# Abstractions for system-level files and streams.
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class sysfile:
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    "A system-level file object."
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    def __init__(self, fd):
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        "Initialise the file with the given 'fd'."
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        self.fd = fd
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    def read(self, n):
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        "Read 'n' bytes from the file, returning a string."
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        return read(self.fd, n)
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    def write(self, s):
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        "Write string 's' to the file."
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        return write(self.fd, s)
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    def close(self):
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        "Close the file."
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        close(self.fd)
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class sysstream(filestream):
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    "A system-level stream object."
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    def __init__(self, fd, mode="r", encoding=None, bufsize=1024):
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        """
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        Initialise the stream with the given 'fd', 'mode', 'encoding' and
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        'bufsize'.
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        """
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        check_int(fd)
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        check_string(mode)
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        get_using(filestream.__init__, self)(encoding, bufsize)
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        self.__data__ = _fdopen(fd, mode)
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# Standard streams.
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stdin = sysstream(0)
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stdout = sysstream(1, "w")
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stderr = sysstream(2, "w")
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# Localised streams.
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# Perform locale initialisation explicitly to ensure that the locale module
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# and various function defaults have been initialised.
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locale.initlocale()
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lstdin = sysstream(0, "r", locale.getpreferredencoding())
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# Input/output functions.
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def close(fd):
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    "Close the file descriptor 'fd'."
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    _close(fd)
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def fdopen(fd, mode="r"):
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    """
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    Open a stream for the given file descriptor 'fd', operating in the given
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    'mode'.
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    """
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    return sysstream(fd, mode)
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def read(fd, n):
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    """
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    Read using the low-level file descriptor 'fd' the given number of bytes 'n'.
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    """
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    check_int(fd)
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    check_int(n)
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    return _read(fd, n)
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def write(fd, s):
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    "Write using the low-level file descriptor 'fd' the given string 's'."
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    check_int(fd)
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    check_string(s)
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    return _write(fd, s)
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