// Amazon's requirements (i.e. DNS naming conventions). It must be 3-63
// characters long, and it must be a sequence of one or more labels
// separated by periods. Each label can contain lowercase ascii
// letters, decimal digits and hyphens, but must not begin or end with
// a hyphen. See:
// http://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html
func IsValidBucketName(bucket string) bool {

		return coalesce(argVals)

	case sqlFnNullIf:
		return nullif(argVals[0], argVals[1])

	case sqlFnCharLength, sqlFnCharacterLength:
		return charlen(argVals[0])

	case sqlFnLower:
		return lowerCase(argVals[0])

	case sqlFnUpper:
		return upperCase(argVals[0])

	case sqlFnUTCNow:
		return handleUTCNow()

	case sqlFnToString, sqlFnToTimestamp:
		// TODO: implement
		fallthrough

			}
			buf.WriteString(signV4TrimAll(v))
		}
		buf.WriteByte('\n')
	}
	return buf.String()
}

// getSignedHeaders generate a string i.e alphabetically sorted, semicolon-separated list of lowercase request header names
func getSignedHeaders(signedHeaders http.Header) string {
	var headers []string
	for k := range signedHeaders {
		headers = append(headers, strings.ToLower(k))
	}
	sort.Strings(headers)

// Site - holds site info - name and region.
type Site struct {
	Name   string
	Region string
}

var validRegionRegex = regexp.MustCompile("^[a-zA-Z][a-zA-Z0-9-_-]+$")

// validSiteNameRegex - allows lowercase letters, digits and '-', starts with
// letter. At least 2 characters long.
var validSiteNameRegex = regexp.MustCompile("^[a-z][a-z0-9-]+$")

// LookupSite - get site related configuration. Loads configuration from legacy