73 lines
2.5 KiB
Kotlin
73 lines
2.5 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.structure
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import dorkbox.bytes.LittleEndian
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import dorkbox.bytes.LittleEndian.Int_.from
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import dorkbox.cabParser.CabException
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import dorkbox.cabParser.Checksum
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import dorkbox.cabParser.CorruptCabException
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import java.io.EOFException
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import java.io.IOException
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import java.io.InputStream
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class CfDataRecord(private val sizeOfBlockData: Int) {
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/** checksum of this CFDATA entry , 4bytes */
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private var csum = 0
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/** number of compressed bytes in this block , 2bytes */
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var cbData = 0
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/** number of uncompressed bytes in this block , 2bytes */
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var cbUncomp = 0
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@Throws(IOException::class, CabException::class)
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fun read(input: InputStream, bytes: ByteArray) {
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csum = from(input) // safe to use signed here, since checksum also returns signed
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cbData = LittleEndian.UShort_.from(input).toInt()
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cbUncomp = LittleEndian.UShort_.from(input).toInt()
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if (cbData > bytes.size) {
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throw CorruptCabException("Corrupt cfData record")
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}
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if (sizeOfBlockData != 0) {
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input.skip(sizeOfBlockData.toLong())
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}
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var readTotal = 0
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while (readTotal < cbData) {
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val read = input.read(bytes, readTotal, cbData - readTotal)
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if (read < 0) {
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throw EOFException()
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}
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readTotal += read
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}
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}
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private fun checksum(bytes: ByteArray): Int {
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val arrayOfByte = ByteArray(4)
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arrayOfByte[0] = (cbData and 0xFF).toByte()
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arrayOfByte[1] = (cbData ushr 8 and 0xFF).toByte()
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arrayOfByte[2] = (cbUncomp and 0xFF).toByte()
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arrayOfByte[3] = (cbUncomp ushr 8 and 0xFF).toByte()
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return Checksum.calculate(bytes, cbData, Checksum.calculate(arrayOfByte, 4, 0))
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}
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fun validateCheckSum(bytesToCheck: ByteArray): Boolean {
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return checksum(bytesToCheck) == csum
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}
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}
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