return signature
}

// compareSignatureV2 returns true if and only if both signatures
// are equal. The signatures are expected to be base64 encoded strings
// according to the AWS S3 signature V2 spec.
func compareSignatureV2(sig1, sig2 string) bool {
	// Decode signature string to binary byte-sequence representation is required
	// as Base64 encoding of a value is not unique:

func (c *Client) LastError() error {
	c.RLock()
	defer c.RUnlock()
	return fmt.Errorf("[%s] %w", c.lastErrTime.Format(time.RFC3339), c.lastErr)
}

// computes the exponential backoff duration according to
// https://www.awsarchitectureblog.com/2015/03/backoff.html
func exponentialBackoffWait(r *rand.Rand, unit, cap time.Duration) func(uint) time.Duration {
	if unit > time.Hour {
		// Protect against integer overflow

		// Different AMZ date
		{Bucket: "testbucket", Key: "user/user1/filename/${filename}/myfile.txt", XAmzMetaUUID: "14365123651274", XAmzDate: "2017T000000Z", XAmzAlgorithm: "AWS4-HMAC-SHA256", ContentType: "image/jpeg", expectedErr: fmt.Errorf("Invalid according to Policy: Policy Condition failed")},

	r := []rune(text)
	if len(r) == 0 {
		return "", false
	}
	return string(r[1:]), true
}

func evalSQLSubstring(s string, startIdx, length int) (res string, err error) {
	rs := []rune(s)

	// According to s3 document, if startIdx < 1, it is set to 1.
	if startIdx < 1 {
		startIdx = 1
	}

	if startIdx > len(rs) {
		startIdx = len(rs) + 1
	}

	// StartIdx is 1-based in the input
	startIdx--

// an object. It indicates that the object itself or its metadata was
// modified accidentally or maliciously.
type Error struct {
	msg   string
	cause error
}

// Errorf - formats according to a format specifier and returns
// the string as a value that satisfies error of type crypto.Error
func Errorf(format string, a ...interface{}) error {
	e := fmt.Errorf(format, a...)
	ee := Error{}
	ee.msg = e.Error()

// (m[key]) from the map. If m is nil or there is no such element, delete
// is a no-op.
func delete(m map[Type]Type1, key Type)

// The len built-in function returns the length of v, according to its type:
//
//	Array: the number of elements in v.
//	Pointer to array: the number of elements in *v (even if v is nil).
//	Slice, or map: the number of elements in v; if v is nil, len(v) is zero.

			// client sent this as part of signed headers we need to
			// handle otherwise we would see a signature mismatch.
			// `aws-cli` sets this as part of signed headers.
			//
			// According to
			// http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.20
			// Expect header is always of form:
			//
			//   Expect       =  "Expect" ":" 1#expectation

	// Get start part index and offset.
	partIndex, partOffset, err := fi.ObjectToPartOffset(ctx, startOffset)
	if err != nil {
		return InvalidRange{startOffset, length, fi.Size}
	}

	// Calculate endOffset according to length
	endOffset := startOffset
	if length > 0 {
		endOffset += length - 1
	}

	// Get last part index to read given length.
	lastPartIndex, _, err := fi.ObjectToPartOffset(ctx, endOffset)

	globalDirSuffixWithSlash       = globalDirSuffix + slashSeparator

	// Add new global values here.
)

const (
	// Limit fields size (except file) to 1Mib since Policy document
	// can reach that size according to https://aws.amazon.com/articles/1434
	maxFormFieldSize = int64(1 * humanize.MiByte)

	// The maximum allowed time difference between the incoming request
	// date and server date during signature verification.

			return err
		}
		f, err := fsys.Open(name)
		if err != nil {
			return err
		}
		defer f.Close()
		_, err = io.Copy(tw, f)
		return err
	})
}

// splitUSTARPath splits a path according to USTAR prefix and suffix rules.
// If the path is not splittable, then it will return ("", "", false).
func splitUSTARPath(name string) (prefix, suffix string, ok bool) {
	length := len(name)