TypeXHeader = 'x'

	// Type 'g' is used by the PAX format to store key-value records that
	// are relevant to all subsequent files.
	// This package only supports parsing and composing such headers,
	// but does not currently support persisting the global state across files.
	TypeXGlobalHeader = 'g'

	// Type 'S' indicates a sparse file in the GNU format.
	TypeGNUSparse = 'S'

template literal, controlled by the
[`jstmpllitinterp` setting](/pkg/html/template#hdr-Security_Model).
This behavior was backported to Go 1.19.8+ and Go 1.20.3+.

Go 1.21 introduced a limit on the maximum number of MIME headers and multipart
forms, controlled by the
[`multipartmaxheaders` and `multipartmaxparts` settings](/pkg/mime/multipart#hdr-Limits)
respectively.
This behavior was backported to Go 1.19.8+ and Go 1.20.3+.

}

// readGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers.
// If they are found, then this function reads the sparse map and returns it.
// This assumes that 0.0 headers have already been converted to 0.1 headers
// by the PAX header parsing logic.
func (tr *Reader) readGNUSparsePAXHeaders(hdr *Header) (sparseDatas, error) {
	// Identify the version of GNU headers.
	var is1x0 bool

	// flag bit is set. However, there are several problems:
	//
	//	* Many ZIP readers still do not support UTF-8.
	//	* If the UTF-8 flag is cleared, several readers simply interpret the
	//	name and comment fields as whatever the local system encoding is.
	//
	// In order to avoid breaking readers without UTF-8 support,
	// we avoid setting the UTF-8 flag if the strings are CP-437 compatible.

					"GOLANG.pkg":     "tar",
				},
			}, nil},
			testClose{nil},
		},
	}, {
		// Craft a theoretically valid PAX archive with global headers.
		// The GNU and BSD tar tools do not parse these the same way.
		//
		// BSD tar v3.1.2 parses and ignores all global headers;
		// the behavior is verified by researching the source code.
		//
		//	$ bsdtar -tvf pax-global-records.tar

		}
	}
}

func TestHeaderAllowedFormats(t *testing.T) {
	vectors := []struct {
		header  *Header           // Input header
		paxHdrs map[string]string // Expected PAX headers that may be needed
		formats Format            // Expected formats that can encode the header
	}{{
		header:  &Header{},
		formats: FormatUSTAR | FormatPAX | FormatGNU,
	}, {
		header:  &Header{Size: 077777777777},