b64: Base64 Transcoder for Streams

This program is designed to encode and decode a typical Base64 stream from an
input stream.

Installation

make

then

cp b64 /usr/local/bin

For manpage:

cp manpage/b64.1.gz /usr/local/share/man/man1

Usage

Usage: b64 [-e] [-d ASCII/binary] [-i if] [-o of]

Technical information

There are a few technical explanations in the header files. Otherwise, there
is some info here as well.

Default input stream is stdin.
Default output stream is stdout.

fgetc() loads 3 bytes into a 32-bit variable to force big-endian byte order. Then, B64 encoding
is performed using a 6-bit mask and bit shifts and the ASCII-encoded characters are sent to the
output stream.

For decoding, a 32-bit variable is loaded with 3 bytes using fgetc() to force a
big-endian byte order. Then, depending on whether the output is specified to be
either ASCII or binary, the decoded data will be sent to the output stream.

base64 provided by GNU coreutilsis 4 times faster and I attribute this to the
superfluous i/o calls in my program.