139 lines
5.3 KiB
TeX
139 lines
5.3 KiB
TeX
\section{Standard module \sectcode{binhex}}
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\stmodindex{binhex}
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This module encodes and decodes files in binhex4 format, a format
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allowing representation of Macintosh files in ASCII. On the macintosh,
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both forks of a file and the finder information are encoded (or
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decoded), on other platforms only the data fork is handled.
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The \code{binhex} module defines the following functions:
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\renewcommand{\indexsubitem}{(in module binhex)}
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\begin{funcdesc}{binhex}{input\, output}
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Convert a binary file with filename \var{input} to binhex file
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\var{output}. The \var{output} parameter can either be a filename or a
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file-like object (any object supporting a \var{write} and \var{close}
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method).
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\end{funcdesc}
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\begin{funcdesc}{hexbin}{input\optional{\, output}}
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Decode a binhex file \var{input}. \var{Input} may be a filename or a
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file-like object supporting \var{read} and \var{close} methods.
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The resulting file is written to a file named \var{output}, unless the
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argument is empty in which case the output filename is read from the
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binhex file.
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\end{funcdesc}
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\subsection{notes}
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There is an alternative, more powerful interface to the coder and
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decoder, see the source for details.
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If you code or decode textfiles on non-Macintosh platforms they will
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still use the macintosh newline convention (carriage-return as end of
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line).
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As of this writing, \var{hexbin} appears to not work in all cases.
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\section{Standard module \sectcode{uu}}
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\stmodindex{uu}
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This module encodes and decodes files in uuencode format, allowing
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arbitrary binary data to be transferred over ascii-only connections.
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Whereever a file argument is expected, the methods accept either a
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pathname (\code{'-'} for stdin/stdout) or a file-like object.
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Normally you would pass filenames, but there is one case where you
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have to open the file yourself: if you are on a non-unix platform and
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your binary file is actually a textfile that you want encoded
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unix-compatible you will have to open the file yourself as a textfile,
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so newline conversion is performed.
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This code was contributed by Lance Ellinghouse, and modified by Jack
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Jansen.
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The \code{uu} module defines the following functions:
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\renewcommand{\indexsubitem}{(in module uu)}
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\begin{funcdesc}{encode}{in_file\, out_file\optional{\, name\, mode}}
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Uuencode file \var{in_file} into file \var{out_file}. The uuencoded
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file will have the header specifying \var{name} and \var{mode} as the
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defaults for the results of decoding the file. The default defaults
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are taken from \var{in_file}, or \code{'-'} and \code{0666}
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respectively.
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\end{funcdesc}
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\begin{funcdesc}{decode}{in_file\optional{\, out_file\, mode}}
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This call decodes uuencoded file \var{in_file} placing the result on
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file \var{out_file}. If \var{out_file} is a pathname the \var{mode} is
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also set. Defaults for \var{out_file} and \var{mode} are taken from
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the uuencode header.
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\end{funcdesc}
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\section{Built-in Module \sectcode{binascii}} % If implemented in C
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\bimodindex{binascii}
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The binascii module contains a number of methods to convert between
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binary and various ascii-encoded binary representations. Normally, you
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will not use these modules directly but use wrapper modules like
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\var{uu} or \var{hexbin} in stead, this module solely exists because
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bit-manipuation of large amounts of data is slow in python.
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The \code{binascii} module defines the following functions:
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\renewcommand{\indexsubitem}{(in module binascii)}
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\begin{funcdesc}{a2b_uu}{string}
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Convert a single line of uuencoded data back to binary and return the
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binary data. Lines normally contain 45 (binary) bytes, except for the
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last line. Line data may be followed by whitespace.
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\end{funcdesc}
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\begin{funcdesc}{b2a_uu}{data}
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Convert binary data to a line of ascii characters, the return value is
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the converted line, including a newline char. The length of \var{data}
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should be at most 45.
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\end{funcdesc}
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\begin{funcdesc}{a2b_hqx}{string}
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Convert binhex4 formatted ascii data to binary, without doing
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rle-decompression. The string should contain a complete number of
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binary bytes, or (in case of the last portion of the binhex4 data)
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have the remaining bits zero.
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\end{funcdesc}
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\begin{funcdesc}{rledecode_hqx}{data}
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Perform RLE-decompression on the data, as per the binhex4
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standard. The algorithm uses \code{0x90} after a byte as a repeat
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indicator, followed by a count. A count of \code{0} specifies a byte
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value of \code{0x90}. The routine returns the decompressed data,
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unless data input data ends in an orphaned repeat indicator, in which
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case the \var{Incomplete} exception is raised.
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\end{funcdesc}
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\begin{funcdesc}{rlecode_hqx}{data}
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Perform binhex4 style RLE-compression on \var{data} and return the
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result.
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\end{funcdesc}
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\begin{funcdesc}{b2a_hqx}{data}
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Perform hexbin4 binary-to-ascii translation and return the resulting
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string. The argument should already be rle-coded, and have a length
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divisible by 3 (except possibly the last fragment).
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\end{funcdesc}
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\begin{funcdesc}{crc_hqx}{data, crc}
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Compute the binhex4 crc value of \var{data}, starting with an initial
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\var{crc} and returning the result.
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\end{funcdesc}
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\begin{excdesc}{Error}
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Exception raised on errors. These are usually programming errors.
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\end{excdesc}
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\begin{excdesc}{Incomplete}
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Exception raised on incomplete data. These are usually not programming
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errors, but handled by reading a little more data and trying again.
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\end{excdesc}
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