// Empty values for object lock and retention can be skipped.
		if v == "" && equals(k, xhttp.AmzObjectLockMode, xhttp.AmzObjectLockRetainUntilDate) {
			continue
		}

		if stringsHasPrefixFold(k, ReservedMetadataPrefixLower) {
			// Do not need to send any internal metadata
			// values to client.
			continue
		}

			AccessKeyID: cred.AccessKey,
		},
	}
	return eventData, nil
}

func fwdHeadersToS3(h http.Header, w http.ResponseWriter) {
	const trim = "x-amz-fwd-header-"
	for k, v := range h {
		if stringsHasPrefixFold(k, trim) {
			w.Header()[k[len(trim):]] = v
		}
	}
}

func fwdStatusToAPIError(statusCode int, resp *http.Response) *APIError {
	if statusCode < http.StatusBadRequest {
		return nil
	}

		return err
	}
	oi := obj.Clone()
	var (
		newKeyID      string
		newKeyContext kms.Context
	)
	encMetadata := make(map[string]string)
	for k, v := range oi.UserDefined {
		if stringsHasPrefixFold(k, ReservedMetadataPrefixLower) {
			encMetadata[k] = v
		}
	}

	if (sseKMS || sseS3) && r.Encryption.Type == ssekms {
		if err = r.Encryption.Validate(); err != nil {
			return err
		}

// and must not set by clients
func containsReservedMetadata(header http.Header) bool {
	for key := range header {
		if _, ok := validSSEReplicationHeaders[key]; ok {
			return false
		}
		if stringsHasPrefixFold(key, ReservedMetadataPrefix) {
			return true
		}
	}
	return false
}

// isHTTPHeaderSizeTooLarge returns true if the provided
// header is larger than 8 KB or the user-defined metadata

func checkMetaHeaders(signedHeadersMap http.Header, r *http.Request) APIErrorCode {
	// check values from http header
	for k, val := range r.Header {
		if stringsHasPrefixFold(k, "X-Amz-Meta-") {
			if signedHeadersMap.Get(k) == val[0] {
				continue
			}
			return ErrUnsignedHeaders
		}
	}

	return ErrNone

func unwrapAll(err error) error {
	for {
		werr := errors.Unwrap(err)
		if werr == nil {
			return err
		}
		err = werr
	}
}

// stringsHasPrefixFold tests whether the string s begins with prefix ignoring case.
func stringsHasPrefixFold(s, prefix string) bool {
	// Test match with case first.
	return len(s) >= len(prefix) && (s[0:len(prefix)] == prefix || strings.EqualFold(s[0:len(prefix)], prefix))
}

				m[v] = strings.Join(value, ",")
			} else {
				m[supportedHeader] = strings.Join(value, ",")
			}
		}
	}

	for key := range v {
		for _, prefix := range userMetadataKeyPrefixes {
			if !stringsHasPrefixFold(key, prefix) {
				continue
			}
			value, ok := nv[http.CanonicalHeaderKey(key)]
			if ok {
				m[key] = strings.Join(value, ",")
				break
			}
		}
	}
	return nil
}

				}
			}

			// None of the provided tags filter match skip the object
			return false
		}

		for _, kv := range r.Flags.Filter.Metadata {
			for k, v := range oi.UserDefined {
				if !stringsHasPrefixFold(k, "x-amz-meta-") && !isStandardHeader(k) {
					continue
				}
				// We only need to match x-amz-meta or standardHeaders
				if kv.Match(BatchJobKV{Key: k, Value: v}) {
					return true
				}
			}

			// Object (version) must match all x-amz-meta and
			// standard metadata headers
			// specified in the filter
			var match bool
			for k, v := range obj.UserDefined {
				if !stringsHasPrefixFold(k, "x-amz-meta-") && !isStandardHeader(k) {
					continue
				}
				// We only need to match x-amz-meta or standardHeaders
				if kv.Match(BatchJobKV{Key: k, Value: v}) {
					match = true
				}
			}

		for _, prefix := range compareKeys {
			if !stringsHasPrefixFold(k, prefix) {
				continue
			}
			found = true
			break
		}
		if found {
			compareMeta1[strings.ToLower(k)] = v
		}
	}

	compareMeta2 := make(map[string]string)
	for k, v := range oi2.Metadata {
		var found bool
		for _, prefix := range compareKeys {
			if !stringsHasPrefixFold(k, prefix) {
				continue
			}