NAME¶
compface, uncompface - compress and expand 48x48x1 face image files
SYNOPSIS¶
compface (buf)
uncompface (buf)
char *buf
DESCRIPTION¶
compface is a function for generating highly compressed representations
of 48x48x1 face image files.
uncompface is an inverse function which
performs an inverse transformation with no loss of data. The algorithm used is
highly tuned for its purpose and achieves better than a five to one
compression ratio on average. In both functions, input is via a NULL
terminated string and a NULL terminated output string is written over the
input string.
Buf should therefore point to a block of 2K size or more
to avoid buffer overruns during output generation.
The input format for
compface (and the output format for
uncompface) is 48 lines each of 3 sixteen bit hexadecimal integers,
comma terminated in C initialiser style. The output format of
compface
(and the input format for
uncompface) is some number of lines made up
of a space followed by printable characters (in the range ``!'' to ``~''
inclusive). The first line contains 72 characters and following lines contain
79 characters except that the last line may be short.
This version of compface has been patched to also be able to handle normal XBM
images. uncompface will produce XBM output only if the -X switch is applied.
The amount of compression obtained varies between face image files but the
output of
compface averages less than 200 characters. The average
number of output lines is three.
DIAGNOSTICS¶
The return value is normally 0. 1 will be returned if extra input has been
ignored during a compress operation. -1 is returned in the case of an invalid
input format. -2 is returned if an internal buffer overrun occurs.
SEE ALSO¶
Compface(1)