c := s[i]
			if 'a' <= c && c <= 'z' {
				c -= 'a' - 'A'
			}
			b[i] = c
		}
		return b
	}
	return Map(unicode.ToUpper, s)
}

// ToLower returns a copy of the byte slice s with all Unicode letters mapped to
// their lower case.
func ToLower(s []byte) []byte {
	isASCII, hasUpper := true, false
	for i := 0; i < len(s); i++ {
		c := s[i]
		if c >= utf8.RuneSelf {
			isASCII = false
			break
		}

// to do case insensitive checks.
func HasSuffix(s string, suffix string) bool {
	if runtime.GOOS == globalWindowsOSName {
		return strings.HasSuffix(strings.ToLower(s), strings.ToLower(suffix))
	}
	return strings.HasSuffix(s, suffix)
}

// Validates if two strings are equal.
func isStringEqual(s1 string, s2 string) bool {
	if runtime.GOOS == globalWindowsOSName {

	if s3Err == ErrNone && retentionMode.Valid() {
		metadata[strings.ToLower(xhttp.AmzObjectLockMode)] = string(retentionMode)
		metadata[strings.ToLower(xhttp.AmzObjectLockRetainUntilDate)] = amztime.ISO8601Format(retentionDate.UTC())
	}
	if s3Err == ErrNone && legalHold.Status.Valid() {
		metadata[strings.ToLower(xhttp.AmzObjectLockLegalHold)] = string(legalHold.Status)
	}
	if s3Err != ErrNone {

	if field.IgnoreMigration {
		return nil
	}

	// found, smart migrate
	fullDataType := strings.TrimSpace(strings.ToLower(m.DB.Migrator().FullDataTypeOf(field).SQL))
	realDataType := strings.ToLower(columnType.DatabaseTypeName())
	var (
		alterColumn bool
		isSameType  = fullDataType == realDataType
	)

	if !field.PrimaryKey {
		// check type

}

// Return canonical headers.
func canonicalizedAmzHeadersV2(headers http.Header) string {
	var keys []string
	keyval := make(map[string]string, len(headers))
	for key := range headers {
		lkey := strings.ToLower(key)
		if !strings.HasPrefix(lkey, "x-amz-") {
			continue
		}
		keys = append(keys, lkey)
		keyval[lkey] = strings.Join(headers[key], ",")
	}
	sort.Strings(keys)
	var canonicalHeaders []string

	var filteredAlgos []string
	found := false
	for _, algo := range want {
		if len(algo) == 0 {
			continue
		}
		for _, allowedAlgo := range allowed {
			algo := strings.ToLower(strings.TrimSpace(algo))
			if algo == allowedAlgo {
				filteredAlgos = append(filteredAlgos, algo)
				found = true
				break
			}
		}
		if !found {

		t.Errorf("invalidRune: expected %q got %q", expect, m)
	}
}

func TestToUpper(t *testing.T) { runStringTests(t, ToUpper, "ToUpper", upperTests) }

func TestToLower(t *testing.T) { runStringTests(t, ToLower, "ToLower", lowerTests) }

func BenchmarkToUpper(b *testing.B) {
	for _, tc := range upperTests {
		tin := []byte(tc.in)
		b.Run(tc.in, func(b *testing.B) {
			for i := 0; i < b.N; i++ {

				return
			}
		}
	}

	for idx, ownField := range ownForeignFields {
		joinFieldName := cases.Title(language.Und, cases.NoLower).String(schema.Name) + ownField.Name
		if len(joinForeignKeys) > idx {
			joinFieldName = cases.Title(language.Und, cases.NoLower).String(joinForeignKeys[idx])
		}

		ownFieldsMap[joinFieldName] = ownField
		fieldsMap[joinFieldName] = ownField

		}
		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
			}
			found = true
			break
		}
		if found {
			compareMeta2[strings.ToLower(k)] = strings.Join(v, ",")
		}
	}

		}
		return errSignatureMismatch
	}

	// Parse trailers.
	wantTrailers := make(map[string]struct{}, len(cr.trailers))
	for k := range cr.trailers {
		wantTrailers[strings.ToLower(k)] = struct{}{}
	}
	input := bufio.NewScanner(bytes.NewReader(valueBuffer.Bytes()))
	for input.Scan() {
		line := strings.TrimSpace(input.Text())
		if line == "" {
			continue
		}