/*
Name   : UNIQ.C
Date   : 13 December, 1989
Author : Kim Moser
System : Microsoft C 5.1
Descrip: Writes either unique or non-unique lines from stdin.
	 Assumes lines are < MAX chars.
*/

#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>

#define MAX_LINE_LEN	2048  /* Longest line allowed */

static char BUF[MAX_LINE_LEN+1] = {"\0"}, PREV[MAX_LINE_LEN+1] = {"\0"};
static int DUPES = 0;  /* Whether to print duplicate lines only */
static int ONCE = 0;

static int COLUMN = -1;  /* Set at runtime */
static int WIDTH = -1;  /* Set at runtime */

static void usage(void);
static void usage(void)
{
	fputs("UNIQ  v1.0  Copyright (c) 1989 by Kim Moser   All Rights Reserved\n\
Usage: UNIQ [-o|-d -c<column> -w<width>]\n\n\
   No switches: writes lines which differ from previous line (strips dupes).\n\
   -o writes only lines which are unique.\n\
   -d writes one copy of only duplicate lines (strips uniques).\n\
   -c specifies which column to compare (default=1)\n\
   -w specifies maximum characters to compare (default=entire line)\n\
",
		stderr
	);
	exit(-1);
}

static void parse(char *s);
static void parse(char *s)
{
	if (s[0]=='-') {
		switch(toupper(s[1])) {
			case 'D':
				DUPES = 1;
				break;
			case 'O':
				ONCE = 1;
				break;
			case 'C':
				if ((COLUMN = atoi(s+2)) < 0) {
					usage();
				}
				COLUMN--;  /* Make it offset from 0 */
				break;
			case 'W':
				if ((WIDTH = atoi(s+2)) <= 0) {
					usage();
				}
				break;
			default:
				usage();
		}
	} else {
		usage();
	}
}

static void uniq(void);
static void uniq(void)
{
	while (!feof(stdin)) {
		strcpy(PREV, BUF);
		if (gets(BUF) == NULL) break;
		if (strncmp(strlen(BUF) > COLUMN ? BUF+COLUMN : "", strlen(PREV) > COLUMN ? PREV+COLUMN : "", WIDTH)) puts(BUF);
	}
}

static void once(void);
static void once(void)
{
	int sameasprev=0;
	int first=1;

	while (!feof(stdin)) {
		strcpy(PREV, BUF);
		gets(BUF);
		if (strncmp(strlen(BUF) > COLUMN ? BUF+COLUMN : "", strlen(PREV) > COLUMN ? PREV+COLUMN : "", WIDTH)) {
			/* They're different */
			if (!sameasprev) {
				if (!first) puts(PREV);
			}
			sameasprev = 0;
		} else {
			/* They're the same */
			sameasprev = 1;
		}
		first = 0;
	}
}

static void dupes(void);
static void dupes(void)
{
	int thisgroup=0;  /* Whether one of these identical lines was printed */

	while (!feof(stdin)) {
		strcpy(PREV, BUF);
		if (gets(BUF) == NULL) break;
		if (strncmp(strlen(BUF) > COLUMN ? BUF+COLUMN : "", strlen(PREV) > COLUMN ? PREV+COLUMN : "", WIDTH)) {
			thisgroup = 0;
		} else {
			if (!thisgroup) {
				thisgroup = 1;
				puts(BUF);
			}
		}
	}
}

void main(int argc, char **argv)
{
	int i;

	for (i=1; i<argc; i++) parse(argv[i]);

	fprintf(stderr, "UNIQ: Printing ");
	if (DUPES) {
		fputs("duplicate lines.\n", stderr);
	} else if (ONCE) {
		fputs("lines which appear only once.\n", stderr);
	} else {
		fputs("unique lines.\n", stderr);
	}

	if (COLUMN == -1) {
		COLUMN = 0;
		fprintf(stderr, "Column = %d\n",
			COLUMN
		);
	}

	fputs("Width = ", stderr);
	if (WIDTH == -1) {
		fputs("line length\n", stderr);
		WIDTH = MAX_LINE_LEN-1;
	} else {
		fprintf(stderr, "%d\n", WIDTH);
	}

	if (DUPES) {
		dupes();
	} else if (ONCE) {
		once();
	} else {
		uniq();
	}
}