44 lines
1.3 KiB
Kotlin
44 lines
1.3 KiB
Kotlin
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package com.stevesoltys.backup.header
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import java.nio.charset.Charset
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internal const val VERSION: Byte = 0
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internal const val MAX_PACKAGE_LENGTH_SIZE = 255
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internal const val MAX_KEY_LENGTH_SIZE = MAX_PACKAGE_LENGTH_SIZE
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internal const val MAX_VERSION_HEADER_SIZE = 1 + Short.SIZE_BYTES * 2 + MAX_PACKAGE_LENGTH_SIZE + MAX_KEY_LENGTH_SIZE
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/**
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* After the first version byte of each backup stream
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* must follow followed this header encrypted with authentication.
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*/
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data class VersionHeader(
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internal val version: Byte = VERSION, // 1 byte
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internal val packageName: String, // ?? bytes (max 255)
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internal val key: String? = null // ?? bytes
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) {
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init {
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check(packageName.length <= MAX_PACKAGE_LENGTH_SIZE)
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key?.let { check(key.length <= MAX_KEY_LENGTH_SIZE) }
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}
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}
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internal const val SEGMENT_LENGTH_SIZE: Int = Short.SIZE_BYTES
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internal const val MAX_SEGMENT_LENGTH: Int = Short.MAX_VALUE.toInt()
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internal const val IV_SIZE: Int = 12
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internal const val SEGMENT_HEADER_SIZE = SEGMENT_LENGTH_SIZE + IV_SIZE
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/**
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* Each data segment must start with this header
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*/
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class SegmentHeader(
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internal val segmentLength: Short, // 2 bytes
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internal val nonce: ByteArray // 12 bytes
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) {
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init {
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check(nonce.size == IV_SIZE)
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}
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}
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val Utf8: Charset = Charset.forName("UTF-8")
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