usr/src/usr.bin/locate/bigram/locate.bigram.c

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * James A. Woods.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)locate.bigram.c     4.6 (Berkeley) %G%";
#endif /* not lint */

/*
 *  bigram < text > bigrams
 *
 * List bigrams for 'updatedb' script.
 * Use 'code' to encode a file using this output.
 */

#include <stdio.h>
#include <sys/param.h>                  /* for MAXPATHLEN */

char buf1[MAXPATHLEN] = " ";
char buf2[MAXPATHLEN];

main ( )
{
        register char *cp;
        register char *oldpath = buf1, *path = buf2;

        while ( fgets ( path, sizeof(buf2), stdin ) != NULL ) {

                /* skip longest common prefix */
                for ( cp = path; *cp == *oldpath; cp++, oldpath++ )
                        if ( *oldpath == NULL )
                                break;
                /*
                 * output post-residue bigrams only
                 */
                while ( *cp != NULL && *(cp + 1) != NULL ) {
                        putchar ( *cp++ );
                        putchar ( *cp++ );
                        putchar ( '\n' );
                }
                if ( path == buf1 )             /* swap pointers */
                        path = buf2, oldpath = buf1;
                else
                        path = buf1, oldpath = buf2;
        }
}