MangaReader.to: refactor, fixes and improvements (#13300)

* MangaReader.to: refactor, fixes and improvements

* rewrite image descrambling interceptor

* add changelog

* use contains to check dupe number instead of endsWith

* memoize calculation result instead of using lookup table

* make SeedRandom private

* add some line breaks to better align diffs

* fix media type

* use the same buffer to reduce memory allocations

* Review changes and inline stuff

* get rid of the hassle of calculating piece count

src/all/mangareaderto/CHANGELOG.md

@@ -0,0 +1,31 @@
+## 1.3.3
+
+- Appended `.to` to extension name
+- Replaced dependencies
+  - `android.net.Uri` → `okhttp3.HttpUrl`
+  - `org.json` → `kotlinx.serialization`
+- Refactored some code to separate files
+- Image quality preference: added prompt to summary and made it take effect without restart, fixes [#12504](https://github.com/tachiyomiorg/tachiyomi-extensions/issues/12504)
+- Added preference to show additional entries in volumes in list results and added code to support volumes, fixes [#12573](https://github.com/tachiyomiorg/tachiyomi-extensions/issues/12573)
+- Improved parsing
+  - Added code to parse authors and artists
+  - Improved chapter list parsing
+  - Other improvements
+  - Performance boosts in selectors
+- Added French, Korean and Chinese languages
+- Corrected filter note type (Text → Header)
+- Rewrote image descrambler
+  - Used fragment in URL instead of appending error-prone query parameter, hopefully fixes [#12722](https://github.com/tachiyomiorg/tachiyomi-extensions/issues/12722)
+  - Made interceptor singleton to be shared across languages
+  - Simplified code logic to make it a lot more readable, thanks to Vetle in [#9325 (comment)](https://github.com/tachiyomiorg/tachiyomi-extensions/pull/9325#issuecomment-1100950110) for code reference
+  - Used `javax.crypto.Cipher` for ARC4
+  - Memoize permutation result to reduce calculation
+  - Save as compressed JPG instead of PNG to avoid size bloat (original image is already compressed)
+
+## 1.2.2
+
+- Fixes filters causing manga list to fail to load.
+
+## 1.2.1
+
+- Builds on original PR and unscrambles the images.

src/all/mangareaderto/build.gradle

@@ -1,11 +1,12 @@
 apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
+apply plugin: 'kotlinx-serialization'
 
 ext {
-    extName = 'MangaReader'
+    extName = 'MangaReader.to'
     pkgNameSuffix = 'all.mangareaderto'
     extClass = '.MangaReaderFactory'
-    extVersionCode = 2
+    extVersionCode = 3
     isNsfw = true
 }
 

src/all/mangareaderto/src/eu/kanade/tachiyomi/extension/all/mangareaderto/MangaReader.kt

@@ -1,22 +1,26 @@
 package eu.kanade.tachiyomi.extension.all.mangareaderto
 
 import android.app.Application
-import android.net.Uri
-import androidx.preference.ListPreference
 import androidx.preference.PreferenceScreen
 import eu.kanade.tachiyomi.network.GET
-import eu.kanade.tachiyomi.network.asObservableSuccess
 import eu.kanade.tachiyomi.source.ConfigurableSource
 import eu.kanade.tachiyomi.source.model.FilterList
+import eu.kanade.tachiyomi.source.model.MangasPage
 import eu.kanade.tachiyomi.source.model.Page
 import eu.kanade.tachiyomi.source.model.SChapter
 import eu.kanade.tachiyomi.source.model.SManga
 import eu.kanade.tachiyomi.source.online.ParsedHttpSource
-import eu.kanade.tachiyomi.util.asJsoup
-import org.json.JSONObject
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.jsonObject
+import kotlinx.serialization.json.jsonPrimitive
+import okhttp3.HttpUrl.Companion.toHttpUrl
+import okhttp3.Request
+import okhttp3.Response
 import org.jsoup.Jsoup
 import org.jsoup.nodes.Document
 import org.jsoup.nodes.Element
+import org.jsoup.nodes.TextNode
+import org.jsoup.select.Evaluator
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.get
 
@@ -30,9 +34,29 @@ open class MangaReader(
     override val supportsLatest = true
 
     override val client = network.client.newBuilder()
-        .addInterceptor(MangaReaderImageInterceptor())
+        .addInterceptor(MangaReaderImageInterceptor)
         .build()
 
+    private fun MangasPage.insertVolumeEntries(): MangasPage {
+        if (preferences.showVolume.not()) return this
+        val list = mangas.ifEmpty { return this }
+        val newList = ArrayList<SManga>(list.size * 2)
+        for (manga in list) {
+            val volume = SManga.create().apply {
+                url = manga.url + VOLUME_URL_SUFFIX
+                title = VOLUME_TITLE_PREFIX + manga.title
+                thumbnail_url = manga.thumbnail_url
+            }
+            newList.add(manga)
+            newList.add(volume)
+        }
+        return MangasPage(newList, hasNextPage)
+    }
+
+    override fun latestUpdatesParse(response: Response) = super.latestUpdatesParse(response).insertVolumeEntries()
+    override fun popularMangaParse(response: Response) = super.popularMangaParse(response).insertVolumeEntries()
+    override fun searchMangaParse(response: Response) = super.searchMangaParse(response).insertVolumeEntries()
+
     override fun latestUpdatesRequest(page: Int) =
         GET("$baseUrl/filter?sort=latest-updated&language=$lang&page=$page", headers)
 
@@ -53,37 +77,37 @@ open class MangaReader(
     override fun popularMangaFromElement(element: Element) =
         searchMangaFromElement(element)
 
-    override fun searchMangaRequest(page: Int, query: String, filters: FilterList) =
+    override fun searchMangaRequest(page: Int, query: String, filters: FilterList): Request {
+        val urlBuilder = baseUrl.toHttpUrl().newBuilder()
         if (query.isNotBlank()) {
-            Uri.parse("$baseUrl/search").buildUpon().run {
-                appendQueryParameter("keyword", query)
-                appendQueryParameter("page", page.toString())
-
-                GET(toString(), headers)
+            urlBuilder.addPathSegment("search").apply {
+                addQueryParameter("keyword", query)
+                addQueryParameter("page", page.toString())
             }
         } else {
-            Uri.parse("$baseUrl/filter").buildUpon().run {
-                appendQueryParameter("language", lang)
-                appendQueryParameter("page", page.toString())
+            urlBuilder.addPathSegment("filter").apply {
+                addQueryParameter("language", lang)
+                addQueryParameter("page", page.toString())
                 filters.ifEmpty(::getFilterList).forEach { filter ->
                     when (filter) {
                         is Select -> {
-                            appendQueryParameter(filter.param, filter.selection)
+                            addQueryParameter(filter.param, filter.selection)
                         }
                         is DateFilter -> {
                             filter.state.forEach {
-                                appendQueryParameter(it.param, it.selection)
+                                addQueryParameter(it.param, it.selection)
                             }
                         }
                         is GenresFilter -> {
-                            appendQueryParameter(filter.param, filter.selection)
+                            addQueryParameter(filter.param, filter.selection)
                         }
                         else -> Unit
                     }
                 }
-                GET(toString(), headers)
             }
         }
+        return Request.Builder().url(urlBuilder.build()).headers(headers).build()
+    }
 
     override fun searchMangaSelector() = ".manga_list-sbs .manga-poster"
 
@@ -92,68 +116,117 @@ open class MangaReader(
     override fun searchMangaFromElement(element: Element) =
         SManga.create().apply {
             url = element.attr("href")
-            element.selectFirst(".manga-poster-img").let {
+            element.selectFirst(Evaluator.Tag("img")).let {
                 title = it.attr("alt")
                 thumbnail_url = it.attr("src")
             }
         }
 
-    private val authorSelector = ".item-head:containsOwn(Authors) ~ a"
+    private fun Element.parseAuthorsTo(manga: SManga) {
+        val authors = select(Evaluator.Tag("a"))
+        val text = authors.map { it.ownText().replace(",", "") }
+        val count = authors.size
+        when (count) {
+            0 -> return
+            1 -> {
+                manga.author = text[0]
+                return
+            }
+        }
+        val nodes = childNodes()
+        val authorList = ArrayList<String>(count)
+        val artistList = ArrayList<String>(count)
+        for ((index, author) in authors.withIndex()) {
+            val nodeIndex = nodes.indexOf(author)
+            val textNode = nodes.getOrNull(nodeIndex + 1) as? TextNode
+            val list = if (textNode != null && "(Art)" in textNode.wholeText) artistList else authorList
+            list.add(text[index])
+        }
+        if (authorList.isEmpty().not()) manga.author = authorList.joinToString()
+        if (artistList.isEmpty().not()) manga.artist = artistList.joinToString()
+    }
 
-    private val statusSelector = ".item-head:containsOwn(Status) + .name"
-
-    override fun mangaDetailsParse(document: Document) =
-        SManga.create().apply {
-            setUrlWithoutDomain(document.location())
-            document.getElementById("ani_detail").let { el ->
-                title = el.selectFirst(".manga-name").text().trim()
-                description = el.selectFirst(".description")?.text()?.trim()
-                thumbnail_url = el.selectFirst(".manga-poster-img").attr("src")
-                genre = el.select(".genres > a")?.joinToString { it.text() }
-                author = el.select(authorSelector)?.joinToString {
-                    it.text().replace(",", "")
-                }
-                artist = author // TODO: separate authors and artists
-                status = when (el.selectFirst(statusSelector)?.text()) {
+    override fun mangaDetailsParse(document: Document) = SManga.create().apply {
+        url = document.location().removePrefix(baseUrl)
+        val root = document.selectFirst(Evaluator.Id("ani_detail"))
+        val mangaTitle = root.selectFirst(Evaluator.Tag("h2")).ownText()
+        title = if (url.endsWith(VOLUME_URL_SUFFIX)) VOLUME_TITLE_PREFIX + mangaTitle else mangaTitle
+        description = root.run {
+            val description = selectFirst(Evaluator.Class("description")).ownText()
+            when (val altTitle = selectFirst(Evaluator.Class("manga-name-or")).ownText()) {
+                "", mangaTitle -> description
+                else -> "$description\n\nAlternative Title: $altTitle"
+            }
+        }
+        thumbnail_url = root.selectFirst(Evaluator.Tag("img")).attr("src")
+        genre = root.selectFirst(Evaluator.Class("genres")).children().joinToString { it.ownText() }
+        for (item in root.selectFirst(Evaluator.Class("anisc-info")).children()) {
+            if (item.hasClass("item").not()) continue
+            when (item.selectFirst(Evaluator.Class("item-head")).ownText()) {
+                "Authors:" -> item.parseAuthorsTo(this)
+                "Status:" -> status = when (item.selectFirst(Evaluator.Class("name")).ownText()) {
                     "Finished" -> SManga.COMPLETED
                     "Publishing" -> SManga.ONGOING
                     else -> SManga.UNKNOWN
                 }
             }
         }
+    }
+
+    override fun chapterListRequest(manga: SManga): Request {
+        val url = manga.url
+        val id = url.removeSuffix(VOLUME_URL_SUFFIX).substringAfterLast('-')
+        val type = if (url.endsWith(VOLUME_URL_SUFFIX)) "vol" else "chap"
+        return GET("$baseUrl/ajax/manga/reading-list/$id?readingBy=$type", headers)
+    }
 
     override fun chapterListSelector() = "#$lang-chapters .item"
 
+    override fun chapterListParse(response: Response): List<SChapter> {
+        val isVolume = response.request.url.queryParameter("readingBy") == "vol"
+        val container = response.parseHtmlProperty().run {
+            val type = if (isVolume) "volumes" else "chapters"
+            selectFirst(Evaluator.Id("$lang-$type")) ?: return emptyList()
+        }
+        val abbrPrefix = if (isVolume) "Vol" else "Chap"
+        val fullPrefix = if (isVolume) "Volume" else "Chapter"
+        return container.children().map { chapterFromElement(it, abbrPrefix, fullPrefix) }
+    }
+
     override fun chapterFromElement(element: Element) =
+        throw UnsupportedOperationException("Not used.")
+
+    private fun chapterFromElement(element: Element, abbrPrefix: String, fullPrefix: String) =
         SChapter.create().apply {
-            chapter_number = element.attr("data-number").toFloatOrNull() ?: -1f
-            element.selectFirst(".item-link").let {
+            val number = element.attr("data-number")
+            chapter_number = number.toFloatOrNull() ?: -1f
+            element.selectFirst(Evaluator.Tag("a")).let {
                 url = it.attr("href")
-                name = it.attr("title")
+                name = run {
+                    val name = it.attr("title")
+                    val prefix = "$abbrPrefix $number: "
+                    if (name.startsWith(prefix).not()) return@run name
+                    val realName = name.removePrefix(prefix)
+                    if (realName.contains(number)) realName else "$fullPrefix $number: $realName"
+                }
             }
         }
 
-    private fun pageListRequest(id: String) =
-        GET("$baseUrl/ajax/image/list/chap/$id?quality=$quality", headers)
+    override fun pageListParse(document: Document): List<Page> {
+        val ajaxUrl = document.selectFirst(Evaluator.Id("wrapper")).run {
+            val readingBy = attr("data-reading-by")
+            val readingId = attr("data-reading-id")
+            "$baseUrl/ajax/image/list/$readingBy/$readingId?quality=${preferences.quality}"
+        }
 
-    override fun fetchPageList(chapter: SChapter) =
-        client.newCall(pageListRequest(chapter)).asObservableSuccess().map { res ->
-            res.asJsoup().getElementById("wrapper").attr("data-reading-id").let {
-                val call = client.newCall(pageListRequest(it))
-                val json = JSONObject(call.execute().body!!.string())
-                pageListParse(Jsoup.parse(json.getString("html")))
-            }
-        }!!
+        val pageDocument = client.newCall(GET(ajaxUrl, headers)).execute().parseHtmlProperty()
 
-    override fun pageListParse(document: Document): List<Page> =
-        document.getElementsByClass("iv-card").mapIndexed { idx, img ->
+        return pageDocument.getElementsByClass("iv-card").mapIndexed { index, img ->
             val url = img.attr("data-url")
-            if (img.hasClass("shuffled")) {
-                Page(idx, "", "$url&shuffled=true")
-            } else {
-                Page(idx, "", url)
-            }
+            val imageUrl = if (img.hasClass("shuffled")) "$url#${MangaReaderImageInterceptor.SCRAMBLED}" else url
+            Page(index, imageUrl = imageUrl)
         }
+    }
 
     override fun imageUrlParse(document: Document) =
         throw UnsupportedOperationException("Not used")
@@ -162,23 +235,8 @@ open class MangaReader(
         Injekt.get<Application>().getSharedPreferences("source_$id", 0x0000)!!
     }
 
-    private val quality by lazy {
-        preferences.getString("quality", "medium")!!
-    }
-
     override fun setupPreferenceScreen(screen: PreferenceScreen) {
-        ListPreference(screen.context).apply {
-            key = "quality"
-            title = "Quality"
-            summary = "%s"
-            entries = arrayOf("Low", "Medium", "High")
-            entryValues = arrayOf("low", "medium", "high")
-            setDefaultValue("medium")
-
-            setOnPreferenceChangeListener { _, newValue ->
-                preferences.edit().putString("quality", newValue as String).commit()
-            }
-        }.let(screen::addPreference)
+        getPreferences(screen.context).forEach(screen::addPreference)
     }
 
     override fun getFilterList() =
@@ -193,4 +251,9 @@ open class MangaReader(
             SortFilter(),
             GenresFilter()
         )
+
+    private fun Response.parseHtmlProperty(): Document {
+        val html = Json.parseToJsonElement(body!!.string()).jsonObject["html"]!!.jsonPrimitive.content
+        return Jsoup.parseBodyFragment(html)
+    }
 }

src/all/mangareaderto/src/eu/kanade/tachiyomi/extension/all/mangareaderto/MangaReaderFactory.kt

@@ -4,5 +4,5 @@ import eu.kanade.tachiyomi.source.SourceFactory
 
 class MangaReaderFactory : SourceFactory {
     override fun createSources() =
-        listOf(MangaReader("en"), MangaReader("ja"))
+        arrayOf("en", "fr", "ja", "ko", "zh").map(::MangaReader)
 }

src/all/mangareaderto/src/eu/kanade/tachiyomi/extension/all/mangareaderto/MangaReaderFilters.kt

@@ -3,7 +3,7 @@ package eu.kanade.tachiyomi.extension.all.mangareaderto
 import eu.kanade.tachiyomi.source.model.Filter
 import java.util.Calendar
 
-object Note : Filter.Text("NOTE: Ignored if using text search!")
+object Note : Filter.Header("NOTE: Ignored if using text search!")
 
 sealed class Select(
     name: String,

src/all/mangareaderto/src/eu/kanade/tachiyomi/extension/all/mangareaderto/MangaReaderImageInterceptor.kt

@@ -5,188 +5,122 @@ import android.graphics.BitmapFactory
 import android.graphics.Canvas
 import android.graphics.Rect
 import okhttp3.Interceptor
-import okhttp3.MediaType.Companion.toMediaTypeOrNull
+import okhttp3.MediaType.Companion.toMediaType
 import okhttp3.Response
 import okhttp3.ResponseBody.Companion.toResponseBody
 import java.io.ByteArrayOutputStream
 import java.io.InputStream
-import kotlin.math.ceil
-import kotlin.math.floor
+import javax.crypto.Cipher
+import javax.crypto.spec.SecretKeySpec
+import kotlin.math.min
 
-class MangaReaderImageInterceptor : Interceptor {
+object MangaReaderImageInterceptor : Interceptor {
 
-    private var s = IntArray(256)
-    private var arc4i = 0
-    private var arc4j = 0
+    private val memo = hashMapOf<Int, IntArray>()
 
     override fun intercept(chain: Interceptor.Chain): Response {
-        val response = chain.proceed(chain.request())
+        val request = chain.request()
+        val response = chain.proceed(request)
 
-        // shuffled page requests should have shuffled=true query parameter
-        if (chain.request().url.queryParameter("shuffled") != "true")
-            return response
+        val url = request.url
+        // TODO: remove the query parameter check (legacy) in later versions
+        if (url.fragment != SCRAMBLED && url.queryParameter("shuffled") == null) return response
 
-        val image = unscrambleImage(response.body!!.byteStream())
-        val body = image.toResponseBody("image/png".toMediaTypeOrNull())
+        val image = descramble(response.body!!.byteStream())
+        val body = image.toResponseBody("image/jpeg".toMediaType())
         return response.newBuilder()
             .body(body)
             .build()
     }
 
-    private fun unscrambleImage(image: InputStream): ByteArray {
+    private fun descramble(image: InputStream): ByteArray {
         // obfuscated code (imgReverser function): https://mangareader.to/js/read.min.js
         // essentially, it shuffles arrays of the image slices using the key 'stay'
 
         val bitmap = BitmapFactory.decodeStream(image)
+        val width = bitmap.width
+        val height = bitmap.height
 
-        val result = Bitmap.createBitmap(bitmap.width, bitmap.height, Bitmap.Config.ARGB_8888)
+        val result = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
         val canvas = Canvas(result)
 
-        val horizontalParts = ceil(bitmap.width / SLICE_SIZE.toDouble()).toInt()
-        val totalParts = horizontalParts * ceil(bitmap.height / SLICE_SIZE.toDouble()).toInt()
-
-        // calculate slices
-        val slices: HashMap<Int, MutableList<Rect>> = hashMapOf()
-
-        for (i in 0 until totalParts) {
-            val row = floor(i / horizontalParts.toDouble()).toInt()
-
-            val x = (i - row * horizontalParts) * SLICE_SIZE
-            val y = row * SLICE_SIZE
-            val width = if (x + SLICE_SIZE <= bitmap.width) SLICE_SIZE else bitmap.width - x
-            val height = if (y + SLICE_SIZE <= bitmap.height) SLICE_SIZE else bitmap.height - y
-
-            val srcRect = Rect(x, y, width, height)
-            val key = width - height
-            if (!slices.containsKey(key)) {
-                slices[key] = mutableListOf()
+        val pieces = ArrayList<Piece>()
+        for (y in 0 until height step PIECE_SIZE) {
+            for (x in 0 until width step PIECE_SIZE) {
+                val w = min(PIECE_SIZE, width - x)
+                val h = min(PIECE_SIZE, height - y)
+                pieces.add(Piece(x, y, w, h))
             }
-            slices[key]?.add(srcRect)
         }
 
-        // handle groups of slices
-        for (sliceEntry in slices) {
-            // reset random number generator for every un-shuffle
-            resetRng()
+        val groups = pieces.groupBy { it.w shl 16 or it.h }
 
-            val currentSlices = sliceEntry.value
-            val sliceCount = currentSlices.count()
+        for (group in groups.values) {
+            val size = group.size
 
-            // un-shuffle slice indices
-            val orderedSlices = IntArray(sliceCount)
-            val keys = MutableList(sliceCount) { it }
+            val permutation = memo.getOrPut(size) {
+                // The key is actually "stay", but it's padded here in case the code is run in
+                // Oracle's JDK, where RC4 key is required to be at least 5 bytes
+                val random = SeedRandom("staystay")
 
-            for (i in currentSlices.indices) {
-                val r = floor(prng() * keys.count()).toInt()
-                val g = keys[r]
-                keys.removeAt(r)
-                orderedSlices[g] = i
+                // https://github.com/webcaetano/shuffle-seed
+                val indices = (0 until size).toMutableList()
+                IntArray(size) { indices.removeAt((random.nextDouble() * indices.size).toInt()) }
             }
 
-            // draw slices
-            val cols = getColumnCount(currentSlices)
+            for ((i, original) in permutation.withIndex()) {
+                val src = group[i]
+                val dst = group[original]
 
-            val groupX = currentSlices[0].left
-            val groupY = currentSlices[0].top
-
-            for ((i, orderedIndex) in orderedSlices.withIndex()) {
-                val slice = currentSlices[i]
-
-                val row = floor((orderedIndex / cols).toDouble()).toInt()
-                val col = orderedIndex - row * cols
-
-                val width = slice.right
-                val height = slice.bottom
-
-                val x = groupX + col * width
-                val y = groupY + row * height
-
-                val srcRect = Rect(x, y, x + width, y + height)
-                val dstRect = Rect(
-                    slice.left,
-                    slice.top,
-                    slice.left + width,
-                    slice.top + height
-                )
+                val srcRect = Rect(src.x, src.y, src.x + src.w, src.y + src.h)
+                val dstRect = Rect(dst.x, dst.y, dst.x + dst.w, dst.y + dst.h)
 
                 canvas.drawBitmap(bitmap, srcRect, dstRect, null)
             }
         }
 
         val output = ByteArrayOutputStream()
-        result.compress(Bitmap.CompressFormat.PNG, 100, output)
+        result.compress(Bitmap.CompressFormat.JPEG, 90, output)
         return output.toByteArray()
     }
 
-    private fun getColumnCount(slices: List<Rect>): Int {
-        if (slices.count() == 1) return 1
-        var t: Int? = null
-        for (i in slices.indices) {
-            if (t == null) t = slices[i].top
-            if (t != slices[i].top) {
-                return i
+    private class Piece(val x: Int, val y: Int, val w: Int, val h: Int)
+
+    // https://github.com/davidbau/seedrandom
+    private class SeedRandom(key: String) {
+        private val input = ByteArray(RC4_WIDTH)
+        private val buffer = ByteArray(RC4_WIDTH)
+        private var pos = RC4_WIDTH
+
+        private val rc4 = Cipher.getInstance("RC4").apply {
+            init(Cipher.ENCRYPT_MODE, SecretKeySpec(key.toByteArray(), "RC4"))
+            update(input, 0, RC4_WIDTH, buffer) // RC4-drop[256]
+        }
+
+        fun nextDouble(): Double {
+            var num = nextByte()
+            var exp = 8
+            while (num < 1L shl 52) {
+                num = num shl 8 or nextByte()
+                exp += 8
             }
+            while (num >= 1L shl 53) {
+                num = num ushr 1
+                exp--
+            }
+            return Math.scalb(num.toDouble(), -exp)
         }
-        return slices.count()
-    }
 
-    private fun resetRng() {
-        arc4i = 0
-        arc4j = 0
-        initializeS()
-        arc4(256) // RC4-drop[256]
-    }
-
-    private fun initializeS() {
-        val t = IntArray(256)
-        for (i in 0..255) {
-            s[i] = i
-            t[i] = KEY[i % KEY.size]
-        }
-        var j = 0
-        var tmp: Int
-        for (i in 0..255) {
-            j = (j + s[i] + t[i]) and 0xFF
-            tmp = s[j]
-            s[j] = s[i]
-            s[i] = tmp
+        private fun nextByte(): Long {
+            if (pos == RC4_WIDTH) {
+                rc4.update(input, 0, RC4_WIDTH, buffer)
+                pos = 0
+            }
+            return buffer[pos++].toLong() and 0xFF
         }
     }
 
-    private fun prng(): Double {
-        var n = arc4(6)
-        var d = 281474976710656.0 // 256^6 (start with 6 chunks in n)
-        var x = 0L
-        while (n < 4503599627370496) { // 2^52 (52 significant digits in a double)
-            n = (n + x) * 256
-            d *= 256
-            x = arc4(1)
-            if (n < 0) break // overflow
-        }
-        return (n + x) / d
-    }
-
-    private fun arc4(count: Int): Long {
-        var t: Int
-        var tmp: Int
-        var r: Long = 0
-
-        repeat(count) {
-            arc4i = (arc4i + 1) and 0xFF
-            arc4j = (arc4j + s[arc4i]) and 0xFF
-            tmp = s[arc4j]
-            s[arc4j] = s[arc4i]
-            s[arc4i] = tmp
-            t = (s[arc4i] + s[arc4j]) and 0xFF
-
-            r = r * 256 + s[t]
-        }
-
-        return r
-    }
-
-    companion object {
-        private val KEY = "stay".map { it.toByte().toInt() }
-        private const val SLICE_SIZE = 200
-    }
+    private const val RC4_WIDTH = 256
+    private const val PIECE_SIZE = 200
+    const val SCRAMBLED = "scrambled"
 }

src/all/mangareaderto/src/eu/kanade/tachiyomi/extension/all/mangareaderto/MangaReaderPreferences.kt

@@ -0,0 +1,41 @@
+package eu.kanade.tachiyomi.extension.all.mangareaderto
+
+import android.content.Context
+import android.content.SharedPreferences
+import androidx.preference.ListPreference
+import androidx.preference.SwitchPreferenceCompat
+
+fun getPreferences(context: Context) = arrayOf(
+
+    ListPreference(context).apply {
+        key = QUALITY_PREF
+        title = "Image quality"
+        summary = "Selected: %s\n" +
+            "Changes will not be applied to chapters that are already loaded or read " +
+            "until you clear the chapter cache."
+        entries = arrayOf("Low", "Medium", "High")
+        entryValues = arrayOf("low", QUALITY_MEDIUM, "high")
+        setDefaultValue(QUALITY_MEDIUM)
+    },
+
+    SwitchPreferenceCompat(context).apply {
+        key = SHOW_VOLUME_PREF
+        title = "Show manga in volumes in search result"
+        setDefaultValue(false)
+    },
+)
+
+val SharedPreferences.quality
+    get() =
+        getString(QUALITY_PREF, QUALITY_MEDIUM)!!
+
+val SharedPreferences.showVolume
+    get() =
+        getBoolean(SHOW_VOLUME_PREF, false)
+
+private const val QUALITY_PREF = "quality"
+private const val QUALITY_MEDIUM = "medium"
+private const val SHOW_VOLUME_PREF = "show_volume"
+
+const val VOLUME_URL_SUFFIX = "#vol"
+const val VOLUME_TITLE_PREFIX = "[VOL] "