//
// The table's lower portion shows specialized features of each format,
// such as supported string encodings, support for sub-second timestamps,
// or support for sparse files.
//
// The Writer currently provides no support for sparse files.
type Format int

// Constants to identify various tar formats.
const (
	// Deliberately hide the meaning of constants from public API.

	// TODO(dsnet): Re-enable this when adding sparse support.
	// See https://golang.org/issue/22735
	/*
		// Handle sparse files.
		var spd sparseDatas
		var spb []byte
		if len(hdr.SparseHoles) > 0 {
			sph := append([]sparseEntry{}, hdr.SparseHoles...) // Copy sparse map
			sph = alignSparseEntries(sph, hdr.Size)
			spd = invertSparseEntries(sph, hdr.Size)

			// Format the sparse map.

			// There are more entries. Read an extension header and parse its entries.
			if _, err := mustReadFull(tr.r, blk[:]); err != nil {
				return nil, err
			}
			s = blk.toSparse()
			continue
		}
		return spd, nil // Done
	}
}

// readGNUSparseMap1x0 reads the sparse map as stored in GNU's PAX sparse format
// version 1.0. The format of the sparse map consists of a series of

	// Keywords for GNU sparse files in a PAX extended header.
	paxGNUSparse          = "GNU.sparse."
	paxGNUSparseNumBlocks = "GNU.sparse.numblocks"
	paxGNUSparseOffset    = "GNU.sparse.offset"
	paxGNUSparseNumBytes  = "GNU.sparse.numbytes"
	paxGNUSparseMap       = "GNU.sparse.map"
	paxGNUSparseName      = "GNU.sparse.name"
	paxGNUSparseMajor     = "GNU.sparse.major"
	paxGNUSparseMinor     = "GNU.sparse.minor"

			}, nil},
			testClose{nil},
		},
		// TODO(dsnet): Re-enable this test when adding sparse support.
		// See https://golang.org/issue/22735
		/*
			}, {
				file: "testdata/gnu-nil-sparse-data.tar",
				tests: []testFnc{
					testHeader{Header{
						Typeflag:    TypeGNUSparse,
						Name:        "sparse.db",
						Size:        1000,
						SparseHoles: []sparseEntry{{Offset: 1000, Length: 0}},

	p.errorCount++
	if p.errorCount > 10 && !*flags.AllErrors {
		log.Fatal("too many errors")
	}
}

func (p *Parser) pos() src.XPos {
	return p.ctxt.PosTable.XPos(src.MakePos(p.lex.Base(), uint(p.lineNum), 0))
}

func (p *Parser) Parse() (*obj.Prog, bool) {
	scratch := make([][]lex.Token, 0, 3)
	for {
		word, cond, operands, ok := p.line(scratch)
		if !ok {
			break
		}

		lexer := lex.NewLexer(f)
		parser := asm.NewParser(ctxt, architecture, lexer)
		ctxt.DiagFunc = func(format string, args ...interface{}) {
			diag = true
			log.Printf(format, args...)
		}
		if *flags.SymABIs {
			ok = parser.ParseSymABIs(buf)
		} else {
			pList := new(obj.Plist)
			pList.Firstpc, ok = parser.Parse()
			// reports errors to parser.Errorf
			if ok {
				obj.Flushplist(ctxt, pList, nil)

	return preSignV4Values, ErrNone
}

// Parses signature version '4' header of the following form.
//
//	Authorization: algorithm Credential=accessKeyID/credScope, \
//	        SignedHeaders=signedHeaders, Signature=signature
func parseSignV4(v4Auth string, region string, stype serviceType) (sv signValues, aec APIErrorCode) {
	// credElement is fetched first to skip replacing the space in access key.

		return false
	}
	today := time.Now()
	expDate, err := time.Parse(time.RFC3339, cert.ExpirationTime)
	if err != nil {
		log.Errorf("certificate timestamp (%v) could not be parsed: %v", cert.ExpirationTime, err)
		return false
	}
	fromDate, err := time.Parse(time.RFC3339, cert.ValidFrom)
	if err != nil {
		log.Errorf("certificate timestamp (%v) could not be parsed: %v", cert.ValidFrom, err)
		return false
	}

// ParsePublicCertFile - parses public cert into its *x509.Certificate equivalent.
func ParsePublicCertFile(certFile string) (x509Certs []*x509.Certificate, err error) {
	// Read certificate file.
	var data []byte
	if data, err = os.ReadFile(certFile); err != nil {
		return nil, err
	}

	// Trimming leading and tailing white spaces.
	data = bytes.TrimSpace(data)

	// Parse all certs in the chain.
	current := data