ParseFileSizeString.kt

fun getBytesFromStringFileSize(fileSizeString: String): Long? {
    fun parseBytes(string: String, unit: String, scale: Double): Long {
        val numberString = string.toUpperCase().replace(unit, "")
        val number = numberString.toDouble()
        return (number * Math.pow(1024.0, scale)).toLong()
    }
    try {
        if (fileSizeString.endsWith("GB", ignoreCase = true)) {
            return parseBytes(fileSizeString, "GB", 3.0)
        }
        if (fileSizeString.endsWith("MB", ignoreCase = true)) {
            return parseBytes(fileSizeString, "MB", 2.0)
        }
        if (fileSizeString.endsWith("KB", ignoreCase = true)) {
            return parseBytes(fileSizeString, "KB", 1.0)
        }
        return parseBytes(fileSizeString, "B", 0.0)
    } catch (e: Exception) { }
    return null
}