// since the specified time otherwise return 412 (precondition failed).
	ifModifiedSinceHeader := r.Header.Get(xhttp.AmzCopySourceIfModifiedSince)
	if ifModifiedSinceHeader != "" {
		if givenTime, err := amztime.ParseHeader(ifModifiedSinceHeader); err == nil {
			if !ifModifiedSince(objInfo.ModTime, givenTime) {
				// If the object is not modified since the specified time.
				writeHeaders()

	// send the correct format.
	http.TimeFormat,
	"Mon, 2 Jan 2006 15:04:05 GMT",
}

// ParseHeader parses http.TimeFormat with an acceptable
// extension for http.TimeFormat - return time might be zero
// if the timeStr is invalid.
func ParseHeader(timeStr string) (time.Time, error) {
	for _, dateFormat := range httpTimeFormats {
		t, err := time.Parse(dateFormat, timeStr)
		if err == nil {

		NumVersions:      fi.NumVersions,
		SuccessorModTime: fi.SuccessorModTime,
		CacheControl:     fi.Metadata["cache-control"],
	}

	if exp, ok := fi.Metadata["expires"]; ok {
		if t, err := amztime.ParseHeader(exp); err == nil {
			objInfo.Expires = t.UTC()
		}
	}

	// Extract etag from metadata.
	objInfo.ETag = extractETag(fi.Metadata)

	// Add user tags to the object info

			return restoreObjStatus{}, errRestoreHDRMalformed
		}
		if strings.TrimSpace(expiryTokens[0]) != "expiry-date" {
			return restoreObjStatus{}, errRestoreHDRMalformed
		}
		expiry, err := amztime.ParseHeader(strings.Trim(expiryTokens[1], `"`))
		if err != nil {
			return restoreObjStatus{}, errRestoreHDRMalformed
		}
		return completedRestoreObj(expiry), nil
	}
	return restoreObjStatus{}, errRestoreHDRMalformed