/*
Program: MERGE.C
Author : Kim Moser
Date   : 19 January, 1991
System : IBM PC / Borland Turbo C 2.0
Descrip: Given two files of sorted words, merges them to stdout.
	 If any words are duplicated, then takes the marked one,
	 if any.
*/

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

#define MAX_LEN		80
/* Max word len */

static void usage(void);
static void usage(void)
{
	fputs("\
usage: MERGE <file1> <file2> [<notefile>]\n\
If <notefile> is specified, then all words that are in file2 but not in file1\n\
will be sent to <notefile>.\n\
", stderr);
	exit(-1);
}

static void readword(FILE *fp, char *dest, int *marked);
static void readword(FILE *fp, char *dest, int *marked)
{
	if (fgets(dest, MAX_LEN, fp) == NULL) {
		dest[0] = '\0';
		*marked = 0;
	} else {
		dest[strlen(dest)-1] = '\0';
		*marked = (dest[strlen(dest)-1] == '*');
		if (*marked) {
			dest[strlen(dest)-1] = '\0';
		}
	}
}

static void outword(char *word, int marked);
static void outword(char *word, int marked)
{
	printf("%s%s\n", word, (marked?"*":""));
}

static FILE *NOTEFILE = NULL;

static void note(char *s);
static void note(char *s)
{
	if (NOTEFILE != NULL) {
		fprintf(NOTEFILE, "%s\n", s);
	}
}

static void finishfile(FILE *fp, int note_yn);
static void finishfile(FILE *fp, int note_yn)
{
	char tmpword[MAX_LEN];
	int tmpint;

	while (1) {
		readword(fp, tmpword, &tmpint);
		if (!tmpword[0]) break;
		outword(tmpword, tmpint);
		if (note_yn) note(tmpword);
	}
}

void main(int argc, char **argv)
{
	FILE *fp1, *fp2;
	char *fname1, *fname2;
	int marked1, marked2;
	char word1[MAX_LEN], word2[MAX_LEN];
	char *notefilename=NULL;

	if (argc < 3 || argc > 4) usage();

	fname1 = argv[1];
	fname2 = argv[2];

	if ((fp1 = fopen(fname1, "r")) == NULL) {
		usage();
	}
	if ((fp2 = fopen(fname2, "r")) == NULL) {
		usage();
	}

	if (argc >= 4) {
		notefilename = argv[3];
		if ((NOTEFILE = fopen(notefilename, "w")) == NULL) {
			usage();
		}
	}

	readword(fp1, word1, &marked1);
	readword(fp2, word2, &marked2);
	while (word1[0] || word2[0]) {
		if (!word1[0]) {
			outword(word2, marked2);
			note(word2);
			finishfile(fp2, 1);
			break;
		} else if (!word2[0]) {
			outword(word1, marked1);
			finishfile(fp1, 0);
			break;
		}
		if (!strcmp(word1, word2)) {
			/* Words are identical, so if either word is
			   marked, output it, otherwise output either. */
			if (marked1) {
				outword(word1, marked1);
			} else {
				outword(word2, marked2);
			}
			readword(fp1, word1, &marked1);
			readword(fp2, word2, &marked2);
		} else {
			if (strcmp(word1, word2) < 0) {
				/* word1 < word2 */
				outword(word1, marked1);
				readword(fp1, word1, &marked1);
			} else {
				outword(word2, marked2);
				note(word2);
				readword(fp2, word2, &marked2);
			}
		}
	}

	if (fclose(fp1)) {
		fprintf(stderr, "Error closing file '%s'.\n", fname1);
	}
	if (fclose(fp2)) {
		fprintf(stderr, "Error closing file '%s'.\n", fname2);
	}

	if (notefilename != NULL) {
		if (fclose(NOTEFILE)) {
			fprintf(stderr, "Error closing note file '%s'.\n", notefilename);
		}
	}

	exit(0);
}