#ifndef lint
static char sccsid[] = "@(#)uudecode.c	5.1 (Berkeley) 7/2/83";
#endif

/*
 * uudecode [input]
 *
 * create the specified file, decoding as you go.
 * used with uuencode.
 *
 * Modified:
 *  PDM 29-Nov-1994  Added support for stripping out a lot of intermediate
 *                   garbage when UU Decoding appended files.
 *                   <Mayer@ljo.dec.com>
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef vms
#include <sys/stat.h>
#include <pwd.h>
#else
#include <unixio.h>
#endif

#ifdef VMS
#define index strchr
#endif

int decode(FILE *in, FILE *out);
void outdec(char *p, FILE *f, int n);
int checkline(char *p, int n);

/* single character decode */
#define DEC(c)	(((c) - ' ') & 077)
#define BUFSIZE 80
#define MAXBYTES 45

int endflag = 0;		/* For filtering out junk */

main(argc, argv)
char **argv;
{
	FILE *in, *out;
	struct stat sbuf;
	int mode;
	char dest[128];
	char buf[BUFSIZE];
	int status;

	/* optional input arg */
	if (argc > 1) {
		if ((in = fopen(argv[1], "r")) == NULL) {
			perror(argv[1]);
			exit(1);
		}
		argv++; argc--;
	} else
		in = stdin;

	if (argc != 1) {
		printf("Usage: uudecode [infile]\n");
		exit(2);
	}

	/* search for header line */
	for (;;) {
		if (fgets(buf, sizeof(buf), in) == NULL) {
			fprintf(stderr, "No begin line\n");
			exit(3);
		}
		if (strncmp(buf, "begin ", 6) == 0)
			break;
	}
	sscanf(buf, "begin %o %s", &mode, dest);

#ifndef vms
	/* handle ~user/file format */
	if (dest[0] == '~') {
		char *sl;
		struct passwd *getpwnam();
		char *index();
		struct passwd *user;
		char dnbuf[100];

		sl = index(dest, '/');
		if (sl == NULL) {
			fprintf(stderr, "Illegal ~user\n");
			exit(3);
		}
		*sl++ = 0;
		user = getpwnam(dest+1);
		if (user == NULL) {
			fprintf(stderr, "No such user as %s\n", dest);
			exit(4);
		}
		strcpy(dnbuf, user->pw_dir);
		strcat(dnbuf, "/");
		strcat(dnbuf, sl);
		strcpy(dest, dnbuf);
	}
#endif

	/* create output file */
#ifndef vms
	out = fopen(dest, "w");
#else
	out = fopen(dest, "w", "alq=300", "deq=100", "fop=tef");
#endif
	if (out == NULL) {
		perror(dest);
		exit(4);
	}
	chmod(dest, mode);

	status = decode(in, out);

	switch (status) {

		case 0:
			break;
		case -1:
			fprintf(stderr, "No end line\n");
			break;
		case -2:
			exit(11);
		default:
			if (fgets(buf, sizeof(buf), in) == NULL ||
			    strcmp(buf, "end\n")) {
			fprintf(stderr, "No end line\n");
			exit(5);
			}
	}
	exit(0);
}

/*
 * copy from in to out, decoding as you go along.
 */
int decode(FILE *in, FILE *out)
{
	char buf[BUFSIZE];
	char *bp;
	int n;
	int status = 1;
	int linelen;

	for (;;) {
		/* for each input line */
		if (fgets(buf, sizeof(buf), in) == NULL) {
			printf("Short file\n");
			status = -2;
			break;
		}
		n = ((buf[0]) - ' ');	/* Don't make it special */
		if (DEC(buf[0]) <= 0) { /* Check the next line   */
			if (fgets(buf, sizeof(buf), in) == NULL) {
		    		status = -1;
				break;
			}
			if (strcmp(buf, "end\n") == 0) {
				status = 0;
				break;
			}
			else {
				n = ((buf[0]) - ' ');
			}
		}
		bp = &buf[1];
		if (checkline(buf, n) == 1) {
			while (n > 0) {
				outdec(bp, out, n);
				bp += 4;
				n -= 3;
			}
		}
	}
	return(status);
}

/*
 * Check that the line is valid before processing it
 */

int checkline(char *lbuf, int n)
{
	int buflen;
	int retval = 1;

	buflen = strlen(lbuf);

	if((strncmp(lbuf, "BEGIN", 5) == 0) && (endflag == 1)) {
	   endflag = 0;
	   return(0);
	}
	if(endflag == 1) {
	   return(0);
	}
	if(strncmp(lbuf, "END", 3) == 0) {
	   endflag = 1;
	   return(0);
	}
	if(((n + 1)/3)*4 > (buflen - 1)) { /* If line too short */
	   return(0);
	}
	if(n > MAXBYTES) {	/* Line cannot be any longer than this */
	   return(0);
	}
	if(n <= 0) {
	   return(0);
	}
	return(retval);
}
/*
 * output a group of 3 bytes (4 input characters).
 * the input chars are pointed to by p, they are to
 * be output to file f.  n is used to tell us not to
 * output all of them at the end of the file.
 */
void outdec(char *p, FILE *f, int n)
{
	int c1, c2, c3;

	c1 = DEC(*p) << 2 | DEC(p[1]) >> 4;
	c2 = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
	c3 = DEC(p[2]) << 6 | DEC(p[3]);
	if (n >= 1)
		putc(c1, f);
	if (n >= 2)
		putc(c2, f);
	if (n >= 3)
		putc(c3, f);
}

/* If your library already has this function, use it */

#ifdef noindex
/*
 * Return the ptr in sp at which the character c appears;
 * NULL if not found
 */

#define	NULL	0

char *
index(sp, c)
register char *sp, c;
{
	do {
		if (*sp == c)
			return(sp);
	} while (*sp++);
	return(NULL);
}
#endif