net.dankito.utils.hashing.HashService.kt Maven / Gradle / Ivy

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package net.dankito.utils.hashing


import net.dankito.utils.io.FileUtils
import java.io.File
import java.io.FileNotFoundException
import java.io.IOException
import java.nio.charset.Charset
import java.security.MessageDigest
import java.security.NoSuchAlgorithmException


open class HashService(protected val fileUtils: FileUtils = FileUtils()) {

    companion object {
        val DefaultDigestCharset: Charset = Charset.forName("UTF-8")
    }


    @Throws(NoSuchAlgorithmException::class)
    open fun hashString(hashAlgorithm: HashAlgorithm, stringToHash: String,
                        charset: Charset = DefaultDigestCharset): String {

        return String(hashStringToBytes(hashAlgorithm, stringToHash), charset)
    }

    @Throws(NoSuchAlgorithmException::class)
    open fun hashStringToBytes(hashAlgorithm: HashAlgorithm, stringToHash: String,
                               charset: Charset = DefaultDigestCharset): ByteArray {

        val messageDigest = MessageDigest.getInstance(hashAlgorithm.algorithmName)
        val stringToHashBytes = stringToHash.toByteArray(charset)

        messageDigest.update(stringToHashBytes)

        return messageDigest.digest()
    }

    @Throws(NoSuchAlgorithmException::class, IOException::class, FileNotFoundException::class)
    open fun getFileHash(hashAlgorithm: HashAlgorithm, file: File): String {
        val messageDigest = MessageDigest.getInstance(hashAlgorithm.algorithmName)

        fileUtils.forEachBlock(file) { buffer, _ ->
            messageDigest.update(buffer)
        }

        val digestBytes = messageDigest.digest()
        val hexString = StringBuilder()

        for(i in 0 until digestBytes.size) {
            hexString.append(String.format("%02x", (0xFF and digestBytes[i].toInt())))
        }

        return hexString.toString()

    }

}