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locate.bigram.c revision 1.2 
      1 /*
      2  * Copyright (c) 1989 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * This code is derived from software contributed to Berkeley by
      6  * James A. Woods.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *	This product includes software developed by the University of
     19  *	California, Berkeley and its contributors.
     20  * 4. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  */
     36 
     37 #ifndef lint
     38 char copyright[] =
     39 "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
     40  All rights reserved.\n";
     41 #endif /* not lint */
     42 
     43 #ifndef lint
     44 /*static char sccsid[] = "from: @(#)locate.bigram.c	4.7 (Berkeley) 6/1/90";*/
     45 static char rcsid[] = "$Id: locate.bigram.c,v 1.2 1993/08/01 18:13:55 mycroft Exp $";
     46 #endif /* not lint */
     47 
     48 /*
     49  *  bigram < text > bigrams
     50  *
     51  * List bigrams for 'updatedb' script.
     52  * Use 'code' to encode a file using this output.
     53  */
     54 
     55 #include <stdio.h>
     56 #include <sys/param.h>			/* for MAXPATHLEN */
     57 
     58 char buf1[MAXPATHLEN] = " ";
     59 char buf2[MAXPATHLEN];
     60 
     61 main ( )
     62 {
     63   	register char *cp;
     64 	register char *oldpath = buf1, *path = buf2;
     65 
     66      	while ( fgets ( path, sizeof(buf2), stdin ) != NULL ) {
     67 
     68 		/* skip longest common prefix */
     69 		for ( cp = path; *cp == *oldpath; cp++, oldpath++ )
     70 			if ( *oldpath == NULL )
     71 				break;
     72 		/*
     73 		 * output post-residue bigrams only
     74 		 */
     75 		while ( *cp != NULL && *(cp + 1) != NULL ) {
     76 			putchar ( *cp++ );
     77 			putchar ( *cp++ );
     78 			putchar ( '\n' );
     79 		}
     80 		if ( path == buf1 )		/* swap pointers */
     81 			path = buf2, oldpath = buf1;
     82 		else
     83 			path = buf1, oldpath = buf2;
     84    	}
     85 }
     86