case '-', '_', '.', '/', '*':
		return false
	}
	return true
}

// s3URLEncode is based on Golang's url.QueryEscape() code,
// while considering some S3 exceptions:
//   - Avoid encoding '/' and '*'
//   - Force encoding of '~'
func s3URLEncode(s string) string {
	spaceCount, hexCount := 0, 0
	for i := 0; i < len(s); i++ {
		c := s[i]
		if shouldEscape(c) {
			if c == ' ' {
				spaceCount++
			} else {
				hexCount++