/*
 *			A R C H X
 *
 * Archive extraction
 *
 */

/*)BUILD	$(TKBOPTIONS) = {
			TASK	= ...ARX
		}
*/

#ifdef	DOCUMENTATION

title	archx	text file archiver extraction
index		text file archiver extraction

synopsis
	arch archive_name

description

	Archx manages archives (libraries) of source files, allowing
	a large number of small files to be stored without using
	excessive system resources.  Archx extracts all files from
	an archive.

	If no archive_name file is given, the standard input is read.
	Archive header records are echoed to the standard output.

archive file format

	Archive files are standard text files.  Each archive element is
	preceeded by a line of the format:
	.s.nf
	-h-	file.name	date	true_name
	.s.f
	Note that there is no line or byte count.  To prevent problems,
	a '-' at the beginning of a record within a user file or embedded
	archive will be "quoted" by doubling it.  The date and true filename
	fields are ignored.  On some operating systems, file.name is
	forced to lowercase.

diagnostics

	Diagnostic messages should be self-explanatory

author

	Martin Minow

bugs

#endif
#include	<stdio.h>
#include	<ctype.h>
#define EOS		0
#define	FALSE		0
#define	TRUE		1
#ifdef	unix
#define	IO_ERROR	1
#endif
#ifdef	vms
extern int	errno;
#define	IO_ERROR	errno
#endif

char		text[513];		/* Working text line		*/
char		name[81];		/* Current archive member name	*/
char		filename[81];		/* Working file name		*/
char		arfilename[81];		/* Archive file name		*/
char		fullname[81];		/* Output for argetname()	*/
int		verbose		= TRUE;	/* TRUE for verbosity		*/
main(argc, argv)
int		argc;			/* Arg count			*/
char		*argv[];		/* Arg vector			*/
{
	register int		i;	/* Random counter		*/
	register char		*fn;	/* File name pointer		*/
	register FILE		*outfd;

	argc = getredirection(argc, argv);
	if (argc > 1 && freopen(argv[1], "r", stdin) == NULL) {
	    perror(argv[1]);
	    exit(IO_ERROR);
	}
	text[0] = EOS;
	while (gethdr()) {
	    if ((outfd = fopen(name, "w")) == NULL) {
		perror(name);
		fprintf(stderr, "Can't create \"%s\"\n", name);
		arskip();
	    }
	    else {
		arexport(outfd);
		fclose(outfd);
	    }
	}
}
int
gethdr()
/*
 * If text is null, read a record, returning TRUE if text contains a header.
 * Parse the header into name.
 */
{
	register char	*tp;
	register char	*np;

again:	if (text[0] == EOS
	 && fgets(text, sizeof text, stdin) == NULL)
	    return (FALSE);
	if (text[0] == '\n' && text[1] == EOS) {
	    text[0] = EOS;
	    goto again;
	}
	if (text[0] != '-'
	 || text[1] != 'h'
	 || text[2] != '-')
	    return (FALSE);
	for (tp = &text[3]; isspace(*tp); tp++)
	    ;
	for (np = name; !isspace(*tp); *np++ = *tp++)
	    ;
	*np = EOS;
	return	(TRUE);
}
arskip()
/*
 * Skip to next header
 */
{
	while (fgets(text, sizeof text, stdin) != NULL) {
	    if (text[0] == '-' && text[1] != '-')
		return;
	}
	text[0] = EOS;				/* EOF signal		*/
}
arexport(outfd)
register FILE	*outfd;
/*
 * Read secret archive format, writing archived data to outfd.
 * Clean out extraneous <cr>,<lf>'s
 */
{
	register char	*tp;
	unsigned int	nrecords;

	printf("Creating \"%s\", ", name);
	nrecords = 0;
	while (fgets(text, sizeof text, stdin) != NULL) {
	    tp = &text[strlen(text)];
	    if (tp > &text[1] && *--tp == '\n' && *--tp == '\r') {
		*tp++ = '\n';
		*tp = EOS;
	    }
	    if (text[0] == '-') {
		if (text[1] != '-')
		    goto gotcha;
		fputs(text+1, outfd);
	    }
	    else {
		fputs(text, outfd);
	    }
	    nrecords++;
	}
	text[0] = EOS;
gotcha:	printf("%u records\n", nrecords);
	if (ferror(stdin) || ferror(outfd))
	    printf("Creation of \"%s\" completed with error\n");
}
/*
 * getredirection() is intended to aid in porting C programs
 * to VMS (Vax-11 C) which does not support '>' and '<'
 * I/O redirection.  With suitable modification, it may
 * useful for other portability problems as well.
 */

static int
getredirection(argc, argv)
int		argc;
char		**argv;
/*
 * Process vms redirection arg's.  Exit if any error is seen.
 * If getredirection() processes an argument, it is erased
 * from the vector.  getredirection() returns a new argc value.
 *
 * Warning: do not try to simplify the code for vms.  The code
 * presupposes that getredirection() is called before any data is
 * read from stdin or written to stdout.
 *
 * Normal usage is as follows:
 *
 *	main(argc, argv)
 *	int		argc;
 *	char		*argv[];
 *	{
 *		argc = getredirection(argc, argv);
 *	}
 */
{
#ifdef	vms
	register char		*ap;	/* Argument pointer	*/
	int			i;	/* argv[] index		*/
	int			j;	/* Output index		*/
	int			file;	/* File_descriptor 	*/
	extern int		errno;	/* Last vms i/o error 	*/

	for (j = i = 1; i < argc; i++) {   /* Do all arguments	*/
	    switch (*(ap = argv[i])) {
	    case '<':			/* <file		*/
		if (freopen(++ap, "r", stdin) == NULL) {
		    perror(ap);		/* Can't find file	*/
		    exit(errno);	/* Is a fatal error	*/
		}

	    case '>':			/* >file or >>file	*/
		if (*++ap == '>') {	/* >>file		*/
		    /*
		     * If the file exists, and is writable by us,
		     * call freopen to append to the file (using the
		     * file's current attributes).  Otherwise, create
		     * a new file with "vanilla" attributes as if
		     * the argument was given as ">filename".
		     * access(name, 2) is TRUE if we can write on
		     * the specified file.
		     */
		    if (access(++ap, 2) == 0) {
			if (freopen(ap, "a", stdout) != NULL)
			    break;	/* Exit case statement	*/
			perror(ap);	/* Error, can't append	*/
			exit(errno);	/* After access test	*/
		    }			/* If file accessable	*/
		}
		/*
		 * On vms, we want to create the file using "standard"
		 * record attributes.  create(...) creates the file
		 * using the caller's default protection mask and
		 * "variable length, implied carriage return"
		 * attributes. dup2() associates the file with stdout.
		 */
		if ((file = creat(ap, 0, "rat=cr", "rfm=var")) == -1
		 || dup2(file, fileno(stdout)) == -1) {
		    perror(ap);		/* Can't create file	*/
		    exit(errno);	/* is a fatal error	*/
		}			/* If '>' creation	*/
		break;			/* Exit case test	*/

	    default:
		argv[j++] = ap;		/* Not a redirector	*/
		break;			/* Exit case test	*/
	    }
	}				/* For all arguments	*/
	return (j);
#else
	/*
	 * Note: argv[] is referenced to fool the Decus C
	 * syntax analyser, supressing an unneeded warning
	 * message.
	 */
	return (argv[0], argc);		/* Just return as seen	*/
#endif
}