static struct zip_magic const magic[] = {
{ ct_tar },
{ ct_none, },
- { ct_compress, 2, "\037\235", "compress", "-Z" },
- { ct_gzip, 2, "\037\213", "gzip", "-z" },
- { ct_bzip2, 3, "BZh", "bzip2", "-j" },
- { ct_lzma, 6, "\xFFLZMA", "lzma", "--lzma" }, /* FIXME: ???? */
- { ct_lzop, 4, "\211LZO", "lzop", "--lzop" },
- { ct_xz, 6, "\0xFD7zXZ", "-J" },
+ { ct_compress, 2, "\037\235", COMPRESS_PROGRAM, "-Z" },
+ { ct_gzip, 2, "\037\213", GZIP_PROGRAM, "-z" },
+ { ct_bzip2, 3, "BZh", BZIP2_PROGRAM, "-j" },
+ { ct_lzma, 6, "\xFFLZMA", LZMA_PROGRAM, "--lzma" },
+ { ct_lzop, 4, "\211LZO", LZOP_PROGRAM, "--lzop" },
+ { ct_xz, 6, "\0xFD7zXZ", XZ_PROGRAM, "-J" },
};
#define NMAGIC (sizeof(magic)/sizeof(magic[0]))
return ct_none;
}
+/* Guess if the archive is seekable. */
+static void
+guess_seekable_archive ()
+{
+ struct stat st;
+
+ if (subcommand_option == DELETE_SUBCOMMAND)
+ {
+ /* The current code in delete.c is based on the assumption that
+ skip_member() reads all data from the archive. So, we should
+ make sure it won't use seeks. On the other hand, the same code
+ depends on the ability to backspace a record in the archive,
+ so setting seekable_archive to false is technically incorrect.
+ However, it is tested only in skip_member(), so it's not a
+ problem. */
+ seekable_archive = false;
+ }
+
+ if (seek_option != -1)
+ {
+ seekable_archive = !!seek_option;
+ return;
+ }
+
+ if (!multi_volume_option && !use_compress_program_option
+ && fstat (archive, &st) == 0)
+ seekable_archive = S_ISREG (st.st_mode);
+ else
+ seekable_archive = false;
+}
+
/* Open an archive named archive_name_array[0]. Detect if it is
a compressed archive of known type and use corresponding decompression
program if so */
ERROR ((0, 0, _("This does not look like a tar archive")));
set_comression_program_by_suffix (archive_name_array[0], NULL);
if (!use_compress_program_option)
- return archive;
+ return archive;
break;
default:
/* FD is not needed any more */
rmtclose (archive);
-
+
hit_eof = false; /* It might have been set by find_next_block in
check_compressed_archive */
{
case ACCESS_READ:
archive = open_compressed_archive ();
+ if (archive >= 0)
+ guess_seekable_archive ();
break;
case ACCESS_WRITE:
case ACCESS_READ:
archive = rmtopen (*archive_name_cursor, O_RDONLY, MODE_RW,
rsh_command_option);
+ guess_seekable_archive ();
break;
case ACCESS_WRITE: