142 lines
3.7 KiB
Kotlin
142 lines
3.7 KiB
Kotlin
/*
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* Copyright 2023 dorkbox, llc
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package dorkbox.cabParser
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import java.io.IOException
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import java.io.InputStream
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internal class CabInputStream(private val inputStream: InputStream) : InputStream() {
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companion object {
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/**
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* Reliably skips over and discards n bytes of data from the input stream
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* @param is input stream
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* @param n the number of bytes to be skipped
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* @return the actual number of bytes skipped
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*
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* @throws IOException
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*/
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@Throws(IOException::class)
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fun betterSkip(`is`: InputStream, n: Long): Long {
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var left = n
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while (left > 0) {
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val l = `is`.skip(left)
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if (l > 0) {
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left -= l
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}
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else if (l == 0L) { // should we retry? lets read one byte
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if (`is`.read() == -1) // EOF
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break
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else left--
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}
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else {
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throw IOException("skip() returned a negative value. This should never happen")
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}
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}
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return n - left
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}
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}
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var currentPosition = 0L
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private set
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private var a: Long = 0
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private val markSupported: Boolean
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init {
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markSupported = inputStream.markSupported()
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}
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@Throws(IOException::class)
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override fun close() {
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inputStream.close()
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}
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@Synchronized
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@Throws(IOException::class)
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override fun reset() {
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if (markSupported) {
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inputStream.reset()
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currentPosition = a
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return
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}
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throw IOException()
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}
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@Throws(IOException::class)
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override fun read(): Int {
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val i = inputStream.read()
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if (i >= 0) {
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currentPosition += 1L
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}
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return i
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}
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@Throws(IOException::class)
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override fun read(bytes: ByteArray): Int {
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val i = inputStream.read(bytes)
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if (i > 0) {
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currentPosition += i.toLong()
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}
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return i
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}
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@Throws(IOException::class)
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override fun read(bytes: ByteArray, offset: Int, length: Int): Int {
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val i = inputStream.read(bytes, offset, length)
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if (i > 0) {
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currentPosition += i.toLong()
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}
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return i
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}
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@Throws(IOException::class)
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override fun available(): Int {
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throw IOException()
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}
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@Synchronized
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override fun mark(paramInt: Int) {
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if (markSupported) {
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a = currentPosition
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inputStream.mark(paramInt)
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}
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}
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override fun markSupported(): Boolean {
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return markSupported
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}
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@Throws(IOException::class)
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fun seek(location: Long) {
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if (location < currentPosition) {
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throw IOException("Cannot seek backwards")
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}
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if (location > currentPosition) {
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skip(location - currentPosition)
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}
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}
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@Throws(IOException::class)
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override fun skip(ammount: Long): Long {
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val l = betterSkip(inputStream, ammount)
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currentPosition += l.toInt().toLong()
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return l
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}
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}
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