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/* vi: set sw=4 ts=4: */
/*
* Mini uniq implementation for busybox
*
*
* Copyright (C) 1999,2000 by Lineo, inc.
* Written by John Beppu <beppu@lineo.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "internal.h"
#include <stdio.h>
#include <string.h>
#include <errno.h>
static const char uniq_usage[] =
"uniq [OPTION]... [INPUT [OUTPUT]]\n"
"Discard all but one of successive identical lines from INPUT (or\n"
"standard input), writing to OUTPUT (or standard output).\n"
"\n"
"\t-h\tdisplay this help and exit\n"
"\n"
"A field is a run of whitespace, then non-whitespace characters.\n"
"Fields are skipped before chars.\n";
/* max chars in line */
#define UNIQ_MAX 4096
typedef void (Print) (FILE *, const char *);
typedef int (Decide) (const char *, const char *);
/* container for two lines to be compared */
typedef struct {
char *a;
char *b;
int recurrence;
FILE *in;
FILE *out;
void *func;
} Subject;
/* set up all the variables of a uniq operation */
static Subject *subject_init(Subject * self, FILE * in, FILE * out,
void *func)
{
self->a = NULL;
self->b = NULL;
self->in = in;
self->out = out;
self->func = func;
self->recurrence = 0;
return self;
}
/* point a and b to the appropriate lines;
* count the recurrences (if any) of a string;
*/
static Subject *subject_next(Subject * self)
{
/* tmp line holders */
static char line[2][UNIQ_MAX];
static int alternator = 0;
if (fgets(line[alternator], UNIQ_MAX, self->in)) {
self->a = self->b;
self->b = line[alternator];
alternator ^= 1;
return self;
}
return NULL;
}
static Subject *subject_last(Subject * self)
{
self->a = self->b;
self->b = NULL;
return self;
}
static Subject *subject_study(Subject * self)
{
if (self->a == NULL) {
return self;
}
if (self->b == NULL) {
fprintf(self->out, "%s", self->a);
return self;
}
if (strcmp(self->a, self->b) == 0) {
self->recurrence++;
} else {
fprintf(self->out, "%s", self->a);
self->recurrence = 0;
}
return self;
}
static int
set_file_pointers(int schema, FILE ** in, FILE ** out, char **argv)
{
switch (schema) {
case 0:
*in = stdin;
*out = stdout;
break;
case 1:
*in = fopen(argv[0], "r");
*out = stdout;
break;
case 2:
*in = fopen(argv[0], "r");
*out = fopen(argv[1], "w");
break;
}
if (*in == NULL) {
fprintf(stderr, "uniq: %s: %s\n", argv[0], strerror(errno));
return errno;
}
if (*out == NULL) {
fprintf(stderr, "uniq: %s: %s\n", argv[1], strerror(errno));
return errno;
}
return 0;
}
/* one variable is the decision algo */
/* another variable is the printing algo */
/* I don't think I have to have more than a 1 line memory
this is the one constant */
/* it seems like GNU/uniq only takes one or two files as an option */
/* ________________________________________________________________________ */
int uniq_main(int argc, char **argv)
{
int i;
char opt;
FILE *in, *out;
Subject s;
/* parse argv[] */
for (i = 1; i < argc; i++) {
if (argv[i][0] == '-') {
opt = argv[i][1];
switch (opt) {
case '-':
case 'h':
usage(uniq_usage);
default:
usage(uniq_usage);
}
} else {
break;
}
}
/* 0 src: stdin; dst: stdout */
/* 1 src: file; dst: stdout */
/* 2 src: file; dst: file */
if (set_file_pointers((argc - 1), &in, &out, &argv[i])) {
exit(1);
}
subject_init(&s, in, out, NULL);
while (subject_next(&s)) {
subject_study(&s);
}
subject_last(&s);
subject_study(&s);
exit(0);
}
/* $Id: uniq.c,v 1.8 2000/04/13 01:18:56 erik Exp $ */
|
