/*
**  UUDECODE.C
**
** uudecode [input]
**
** create the specified file, decoding as you go.
** used with uuencode.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "config.h"
#include "version.h"

IDENT (".02");

#ifdef UNIX
# include <pwd.h>
# include <sys/types.h>
# include <sys/stat.h>
#endif

#ifdef VMS
# include <types.h>
# include <stat.h>
#endif

/* single character decode */
#define DEC(c)	(((c) - ' ') & 077)

void outdec (char *p, FILE *f, int n);
void decode (FILE *, FILE *);
void xerror (char *);

int
main(int argc, char **argv)
{
	FILE *in, *out;
#if defined (UNIX) || defined (VMS)
	struct stat sbuf;
#endif
	int mode;
	char dest[128];
	char buf[80];

	/* optional input arg */
	if (argc > 1) {
		if ((in = fopen(argv[1], "r")) == NULL) {
			xerror(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);

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

		sl = strchr(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 /* UNIX */

	/* create output file */
	out = fopen(dest, "w");
	if (out == NULL) {
		xerror(dest);
		exit(4);
	}
#if defined (UNIX) || defined (VMS)
	chmod(dest, mode);
#endif

	decode(in, out);

	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.
 */

void
decode(FILE *in, FILE *out)
{
	char buf[80];
	char *bp;
	int n;

	for (;;) {
		/* for each input line */
		if (fgets(buf, sizeof buf, in) == NULL) {
			printf("Short file\n");
			exit(10);
		}
		n = DEC(buf[0]);
		if (n <= 0)
			break;

		bp = &buf[1];
		while (n > 0) {
			outdec(bp, out, n);
			bp += 4;
			n -= 3;
		}
	}
}

/*
 * 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);
}


/* fr: like read but stdio */
int
fr(FILE *fd, char *buf, int cnt)
{
	int c, i;

	for (i=0; i<cnt; i++) {
		c = getc(fd);
		if (c == EOF)
			return(i);
		buf[i] = c;
	}
	return (cnt);
}

void
xerror(char *err)
{
    printf("Can not open file \"%s\"\n", err);
}