uuencode.c

编码方式的解码示范uuencode and uudecode are in the public domain. dos2unix and unix2dos are hereby placed in

/*
 *	uuencode [input] output
 *
 * Encode a file so it can be mailed to a remote system.
 *
 * modified for MSDOS by Kenneth J. Hendrickson
 */

#ifdef MSDOS
#include <fcntl.h>
#include <io.h>
#include <process.h>
#endif

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>

/* ENC is the basic 1 character encoding function to make a char printing */
#define ENC(c) (((c) & 077) + ' ')

main(argc, argv)
char **argv;
{
	FILE *in;
	struct stat sbuf;
	int mode;

#ifndef MSDOS
	/* optional 1st argument */
	if (argc > 2) {
		if ((in = fopen(argv[1], "r")) == NULL) {
			perror(argv[1]);
			exit(1);
		}
		argv++; argc--;
	} else
		in = stdin;

	if (argc != 2) {
		printf("Usage: uuencode [infile] remotefile\n");
		exit(2);
	}
#else
	/* no optional 1st argument, input file must be given */
	/* MSDOS handling of stdin is brain-dead.  It thinks EOF
	   occured when a ^Z is read, even if there is more . . . */
	if (argc == 2) {
		if ((in = fopen(argv[1], "r")) == NULL) {
			perror(argv[1]);
			exit(1);
		}
		/* don't translate CRLF into LF when reading */
		(void) setmode(fileno(in), O_BINARY);
	}
	else {
		(void) fprintf(stderr, "Usage: uuencode infile\n");
		exit(2);
	}
#endif

	/* figure out the input file mode */
	fstat(fileno(in), &sbuf);
	mode = sbuf.st_mode & 0777;
	/* for MSDOS, remotefile == infile */
	printf("begin %o %s\n", mode, argv[1]);

	encode(in, stdout);

	printf("end\n");
	exit(0);
}

/*
 * copy from in to out, encoding as you go along.
 */
encode(in, out)
FILE *in;
FILE *out;
{
	char buf[80];
	int i, n;

	for (;;) {
		/* 1 (up to) 45 character line */
		n = fr(in, buf, 45);
		putc(ENC(n), out);

		for (i=0; i<n; i += 3)
			outdec(&buf[i], out);

		putc('\n', out);
		if (n <= 0)
			break;
	}
}

/*
 * output one group of 3 bytes, pointed at by p, on file f.
 */
outdec(p, f)
char *p;
FILE *f;
{
	int c1, c2, c3, c4;

	c1 = *p >> 2;
	c2 = (*p << 4) & 060 | (p[1] >> 4) & 017;
	c3 = (p[1] << 2) & 074 | (p[2] >> 6) & 03;
	c4 = p[2] & 077;
	putc(ENC(c1), f);
	putc(ENC(c2), f);
	putc(ENC(c3), f);
	putc(ENC(c4), f);
}

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

	for (i=0; i<cnt; i++) {
		c = getc(fd);
#ifndef MSDOS
		if (c == EOF)
#else
		if (feof(fd))
#endif
			return(i);
		buf[i] = c;
	}
	return (cnt);
}