jetbrains.exodus.crypto.StreamCipherInputStream.kt Maven / Gradle / Ivy
/**
* Copyright 2010 - 2022 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jetbrains.exodus.crypto
import jetbrains.exodus.kotlin.notNull
import java.io.BufferedInputStream
import java.io.FilterInputStream
import java.io.InputStream
val InputStream.asBuffered: InputStream get() = this as? BufferedInputStream ?: BufferedInputStream(this)
class StreamCipherInputStream(input: InputStream, private val cipherGetter: () -> StreamCipher) : FilterInputStream(input) {
private var cipher: StreamCipher = cipherGetter()
private var position = 0
private var savedPosition = 0
override fun read(): Int {
val b = super.read()
if (b == -1) {
return -1
}
return cipher.cryptAsInt(b.toByte()).apply { ++position }
}
override fun read(bytes: ByteArray?): Int {
val b = bytes.notNull { "Can't read into null array" }
return read(b, 0, b.size)
}
override fun read(bytes: ByteArray?, off: Int, len: Int): Int {
val b = bytes.notNull { "Can't read into null array" }
val read = super.read(b, off, len)
if (read > 0) {
for (i in off until read + off) {
b[i] = cipher.crypt(b[i])
}
position += read
}
return read
}
override fun reset() {
super.reset()
cipher = cipherGetter()
// skip savedPosition bytes
repeat(savedPosition) {
cipher.crypt(0)
}
position = savedPosition
}
override fun mark(readlimit: Int) {
super.mark(readlimit)
savedPosition = position
}
val source: InputStream
get() {
var result = `in`
while (result is FilterInputStream) {
result = `in`
}
return result
}
}