29  * is_tar() -- figure out whether file is a tar archive.
31  * Stolen (by the author!) from the file_public domain tar program:
49 #include "tar.h"
57 	"tar archive",			/* found in ../magic/Magdir/archive */
58 	"POSIX tar archive",
59 	"POSIX tar archive (GNU)",	/*  */
68 	 * Do the tar test first, because if the first file in the tar  in file_is_tar()
71 	int tar;  in file_is_tar()  local
77 	tar = is_tar(buf, nbytes);  in file_is_tar()
78 	if (tar < 1 || tar > 3)  in file_is_tar()
84 	if (file_printf(ms, "%s", mime ? "application/x-tar" :  in file_is_tar()
85 	    tartype[tar - 1]) == -1)  in file_is_tar()
93  *	0 if the checksum is bad (i.e., probably not a tar archive),
94  *	1 for old UNIX tar file,
95  *	2 for Unix Std (POSIX) tar file,
96  *	3 for GNU tar file.
137 		return 0;	/* Not a tar archive */  in is_tar()
141 		return 3;		/* GNU Unix Standard tar archive */  in is_tar()
145 		return 2;		/* Unix Standard tar archive */  in is_tar()
147 	return 1;			/* Old fashioned tar archive */  in is_tar()