*: tar-related cleanups: move struct to unarchive.h; move help to tar.c

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/archival/tar.c b/archival/tar.c
index 344c9de..f49fb12 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -48,37 +48,6 @@
 
 #if ENABLE_FEATURE_TAR_CREATE
 
-/* Tar file constants  */
-
-#define TAR_BLOCK_SIZE		512
-
-/* POSIX tar Header Block, from POSIX 1003.1-1990  */
-#define NAME_SIZE      100
-#define NAME_SIZE_STR "100"
-typedef struct TarHeader {       /* byte offset */
-	char name[NAME_SIZE];     /*   0-99 */
-	char mode[8];             /* 100-107 */
-	char uid[8];              /* 108-115 */
-	char gid[8];              /* 116-123 */
-	char size[12];            /* 124-135 */
-	char mtime[12];           /* 136-147 */
-	char chksum[8];           /* 148-155 */
-	char typeflag;            /* 156-156 */
-	char linkname[NAME_SIZE]; /* 157-256 */
-	/* POSIX:   "ustar" NUL "00" */
-	/* GNU tar: "ustar  " NUL */
-	/* Normally it's defined as magic[6] followed by
-	 * version[2], but we put them together to save code.
-	 */
-	char magic[8];            /* 257-264 */
-	char uname[32];           /* 265-296 */
-	char gname[32];           /* 297-328 */
-	char devmajor[8];         /* 329-336 */
-	char devminor[8];         /* 337-344 */
-	char prefix[155];         /* 345-499 */
-	char padding[12];         /* 500-512 (pad to exactly TAR_BLOCK_SIZE) */
-} TarHeader;
-
 /*
 ** writeTarFile(), writeFileToTarball(), and writeTarHeader() are
 ** the only functions that deal with the HardLinkInfo structure.
@@ -193,7 +162,7 @@
 }
 #define PUT_OCTAL(a, b) putOctal((a), sizeof(a), (b))
 
-static void chksum_and_xwrite(int fd, struct TarHeader* hp)
+static void chksum_and_xwrite(int fd, struct tar_header_t* hp)
 {
 	/* POSIX says that checksum is done on unsigned bytes
 	 * (Sun and HP-UX gets it wrong... more details in
@@ -235,7 +204,7 @@
 		"00000000000",
 		"00000000000",
 	};
-	struct TarHeader header;
+	struct tar_header_t header;
 	int size;
 
 	dir = !!dir; /* normalize: 0/1 */
@@ -262,17 +231,13 @@
 #endif
 
 /* Write out a tar header for the specified file/directory/whatever */
-void BUG_tar_header_size(void);
 static int writeTarHeader(struct TarBallInfo *tbInfo,
 		const char *header_name, const char *fileName, struct stat *statbuf)
 {
-	struct TarHeader header;
+	struct tar_header_t header;
 
-	if (sizeof(header) != 512)
-		BUG_tar_header_size();
-
-	memset(&header, 0, sizeof(struct TarHeader));
-
+	memset(&header, 0, sizeof(header));
+ 
 	strncpy(header.name, header_name, sizeof(header.name));
 
 	/* POSIX says to mask mode with 07777. */
@@ -738,6 +703,68 @@
 }
 #endif
 
+//usage:#define tar_trivial_usage
+//usage:       "-[" IF_FEATURE_TAR_CREATE("c") "xt" IF_FEATURE_SEAMLESS_GZ("z")
+//usage:	IF_FEATURE_SEAMLESS_BZ2("j") IF_FEATURE_SEAMLESS_LZMA("a")
+//usage:	IF_FEATURE_SEAMLESS_Z("Z") IF_FEATURE_TAR_NOPRESERVE_TIME("m") "vO] "
+//usage:	IF_FEATURE_TAR_FROM("[-X FILE] ")
+//usage:       "[-f TARFILE] [-C DIR] [FILE]..."
+//usage:#define tar_full_usage "\n\n"
+//usage:	IF_FEATURE_TAR_CREATE("Create, extract, ")
+//usage:	IF_NOT_FEATURE_TAR_CREATE("Extract ")
+//usage:	"or list files from a tar file\n"
+//usage:     "\nOperation:"
+//usage:	IF_FEATURE_TAR_CREATE(
+//usage:     "\n	c	Create"
+//usage:	)
+//usage:     "\n	x	Extract"
+//usage:     "\n	t	List"
+//usage:     "\nOptions:"
+//usage:     "\n	f	Name of TARFILE ('-' for stdin/out)"
+//usage:     "\n	C	Change to DIR before operation"
+//usage:     "\n	v	Verbose"
+//usage:	IF_FEATURE_SEAMLESS_GZ(
+//usage:     "\n	z	(De)compress using gzip"
+//usage:	)
+//usage:	IF_FEATURE_SEAMLESS_BZ2(
+//usage:     "\n	j	(De)compress using bzip2"
+//usage:	)
+//usage:	IF_FEATURE_SEAMLESS_LZMA(
+//usage:     "\n	a	(De)compress using lzma"
+//usage:	)
+//usage:	IF_FEATURE_SEAMLESS_Z(
+//usage:     "\n	Z	(De)compress using compress"
+//usage:	)
+//usage:     "\n	O	Extract to stdout"
+//usage:	IF_FEATURE_TAR_CREATE(
+//usage:     "\n	h	Follow symlinks"
+//usage:	)
+//usage:	IF_FEATURE_TAR_NOPRESERVE_TIME(
+//usage:     "\n	m	Don't restore mtime"
+//usage:	)
+//usage:	IF_FEATURE_TAR_FROM(
+//usage:	IF_FEATURE_TAR_LONG_OPTIONS(
+//usage:     "\n	exclude	File to exclude"
+//usage:	)
+//usage:     "\n	X	File with names to exclude"
+//usage:     "\n	T	File with names to include"
+//usage:	)
+//usage:
+//usage:#define tar_example_usage
+//usage:       "$ zcat /tmp/tarball.tar.gz | tar -xf -\n"
+//usage:       "$ tar -cf /tmp/tarball.tar /usr/local\n"
+
+// Supported but aren't in --help:
+//	o	no-same-owner
+//	p	same-permissions
+//	k	keep-old
+//	numeric-owner
+//	no-same-permissions
+//	overwrite
+//IF_FEATURE_TAR_TO_COMMAND(
+//	to-command
+//)
+
 enum {
 	OPTBIT_KEEP_OLD = 8,
 	IF_FEATURE_TAR_CREATE(   OPTBIT_CREATE      ,)