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Diffstat (limited to 'usr.bin/locate/code/locate.code.c')
| -rw-r--r-- | usr.bin/locate/code/locate.code.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/usr.bin/locate/code/locate.code.c b/usr.bin/locate/code/locate.code.c new file mode 100644 index 0000000..d3ec29f --- /dev/null +++ b/usr.bin/locate/code/locate.code.c @@ -0,0 +1,212 @@ +/* + * Copyright (c) 1989, 1993 + * 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, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef lint +static char copyright[] = +"@(#) Copyright (c) 1989, 1993\n\ + The Regents of the University of California. All rights reserved.\n"; +#endif /* not lint */ + +#ifndef lint +static char sccsid[] = "@(#)locate.code.c 8.1 (Berkeley) 6/6/93"; +#endif /* not lint */ + +/* + * PURPOSE: sorted list compressor (works with a modified 'find' + * to encode/decode a filename database) + * + * USAGE: bigram < list > bigrams + * process bigrams (see updatedb) > common_bigrams + * code common_bigrams < list > squozen_list + * + * METHOD: Uses 'front compression' (see ";login:", Volume 8, Number 1 + * February/March 1983, p. 8). Output format is, per line, an + * offset differential count byte followed by a partially bigram- + * encoded ascii residue. A bigram is a two-character sequence, + * the first 128 most common of which are encoded in one byte. + * + * EXAMPLE: For simple front compression with no bigram encoding, + * if the input is... then the output is... + * + * /usr/src 0 /usr/src + * /usr/src/cmd/aardvark.c 8 /cmd/aardvark.c + * /usr/src/cmd/armadillo.c 14 armadillo.c + * /usr/tmp/zoo 5 tmp/zoo + * + * The codes are: + * + * 0-28 likeliest differential counts + offset to make nonnegative + * 30 switch code for out-of-range count to follow in next word + * 128-255 bigram codes (128 most common, as determined by 'updatedb') + * 32-127 single character (printable) ascii residue (ie, literal) + * + * SEE ALSO: updatedb.csh, bigram.c + * + * AUTHOR: James A. Woods, Informatics General Corp., + * NASA Ames Research Center, 10/82 + */ + +#include <sys/param.h> +#include <err.h> +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include "locate.h" + +#define BGBUFSIZE (NBG * 2) /* size of bigram buffer */ + +char buf1[MAXPATHLEN] = " "; +char buf2[MAXPATHLEN]; +char bigrams[BGBUFSIZE + 1] = { 0 }; + +int bgindex __P((char *)); +void usage __P((void)); + +int +main(argc, argv) + int argc; + char *argv[]; +{ + register char *cp, *oldpath, *path; + int ch, code, count, diffcount, oldcount; + FILE *fp; + + while ((ch = getopt(argc, argv, "")) != EOF) + switch(ch) { + case '?': + default: + usage(); + } + argc -= optind; + argv += optind; + + if (argc != 1) + usage(); + + if ((fp = fopen(argv[0], "r")) == NULL) + err(1, "%s", argv[0]); + + /* First copy bigram array to stdout. */ + (void)fgets(bigrams, BGBUFSIZE + 1, fp); + if (fwrite(bigrams, 1, BGBUFSIZE, stdout) != BGBUFSIZE) + err(1, "stdout"); + (void)fclose(fp); + + oldpath = buf1; + path = buf2; + oldcount = 0; + while (fgets(path, sizeof(buf2), stdin) != NULL) { + /* Truncate newline. */ + cp = path + strlen(path) - 1; + if (cp > path && *cp == '\n') + *cp = '\0'; + + /* Squelch characters that would botch the decoding. */ + for (cp = path; *cp != NULL; cp++) { + if ((u_char)*cp >= PARITY) + *cp &= PARITY-1; + else if (*cp <= SWITCH) + *cp = '?'; + } + + /* Skip longest common prefix. */ + for (cp = path; *cp == *oldpath; cp++, oldpath++) + if (*oldpath == NULL) + break; + count = cp - path; + diffcount = count - oldcount + OFFSET; + oldcount = count; + if (diffcount < 0 || diffcount > 2 * OFFSET) { + if (putchar(SWITCH) == EOF || + putw(diffcount, stdout) == EOF) + err(1, "stdout"); + } else + if (putchar(diffcount) == EOF) + err(1, "stdout"); + + while (*cp != NULL) { + if (*(cp + 1) == NULL) { + if (putchar(*cp) == EOF) + err(1, "stdout"); + break; + } + if ((code = bgindex(cp)) < 0) { + if (putchar(*cp++) == EOF || + putchar(*cp++) == EOF) + err(1, "stdout"); + } else { + /* Found, so mark byte with parity bit. */ + if (putchar((code / 2) | PARITY) == EOF) + err(1, "stdout"); + cp += 2; + } + } + if (path == buf1) { /* swap pointers */ + path = buf2; + oldpath = buf1; + } else { + path = buf1; + oldpath = buf2; + } + } + /* Non-zero status if there were errors */ + if (fflush(stdout) != 0 || ferror(stdout)) + exit(1); + exit(0); +} + +int +bgindex(bg) /* Return location of bg in bigrams or -1. */ + char *bg; +{ + register char bg0, bg1, *p; + + bg0 = bg[0]; + bg1 = bg[1]; + for (p = bigrams; *p != NULL; p++) + if (*p++ == bg0 && *p == bg1) + break; + return (*p == NULL ? -1 : --p - bigrams); +} + +void +usage() +{ + (void)fprintf(stderr, + "usage: locate.code common_bigrams < list > squozen_list\n"); + exit(1); +} |
