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)

                                         25 January 1990                              COMPFACE(3)