Add headerless bzip2 and gzip library

Signed-off-by: Graham <gpe@openrs2.dev>

asm/build.gradle.kts

@@ -9,6 +9,8 @@ dependencies {
     api("org.ow2.asm:asm-commons:${Versions.asm}")
     api("org.ow2.asm:asm-tree:${Versions.asm}")
     api("org.ow2.asm:asm-util:${Versions.asm}")
+
+    implementation(project(":compress"))
 }
 
 publishing {

asm/src/main/java/dev/openrs2/asm/classpath/Library.kt

@@ -5,14 +5,12 @@ import dev.openrs2.asm.NopClassVisitor
 import dev.openrs2.asm.remap
 import dev.openrs2.common.crypto.Pkcs12KeyStore
 import dev.openrs2.common.io.DeterministicJarOutputStream
-import dev.openrs2.common.io.SkipOutputStream
+import dev.openrs2.compress.gzip.Gzip
 import org.objectweb.asm.ClassReader
 import org.objectweb.asm.commons.Remapper
 import org.objectweb.asm.tree.ClassNode
 import org.objectweb.asm.util.CheckClassAdapter
-import java.io.ByteArrayInputStream
 import java.io.OutputStream
-import java.io.SequenceInputStream
 import java.nio.file.Files
 import java.nio.file.Path
 import java.util.TreeMap
@@ -21,8 +19,6 @@ import java.util.jar.JarInputStream
 import java.util.jar.JarOutputStream
 import java.util.jar.Manifest
 import java.util.jar.Pack200
-import java.util.zip.GZIPInputStream
-import java.util.zip.GZIPOutputStream
 
 class Library constructor() : Iterable<ClassNode> {
     private var classes = TreeMap<String, ClassNode>()
@@ -120,9 +116,7 @@ class Library constructor() : Iterable<ClassNode> {
             writeJar(classPath, temp)
 
             JarInputStream(Files.newInputStream(temp)).use { `in` ->
-                val headerSize = GZIP_HEADER.size.toLong()
+                Gzip.createHeaderlessOutputStream(out).use { gzip ->
-
-                GZIPOutputStream(SkipOutputStream(out, headerSize)).use { gzip ->
                     Pack200.newPacker().pack(`in`, gzip)
                 }
             }
@@ -140,7 +134,6 @@ class Library constructor() : Iterable<ClassNode> {
         private const val CLASS_SUFFIX = ".class"
         private const val TEMP_PREFIX = "tmp"
         private const val JAR_SUFFIX = ".jar"
-        private val GZIP_HEADER = byteArrayOf(0x1F, 0x8B.toByte())
 
         fun readJar(path: Path): Library {
             logger.info { "Reading jar $path" }
@@ -170,10 +163,7 @@ class Library constructor() : Iterable<ClassNode> {
 
             val temp = Files.createTempFile(TEMP_PREFIX, JAR_SUFFIX)
             try {
-                val header = ByteArrayInputStream(GZIP_HEADER)
+                Gzip.createHeaderlessInputStream(Files.newInputStream(path)).use { `in` ->
-                val data = Files.newInputStream(path)
-
-                GZIPInputStream(SequenceInputStream(header, data)).use { `in` ->
                     JarOutputStream(Files.newOutputStream(temp)).use { out ->
                         Pack200.newUnpacker().unpack(`in`, out)
                     }

buildSrc/src/main/java/Versions.kt

@@ -2,6 +2,7 @@ object Versions {
     const val asm = "8.0"
     const val bouncyCastle = "1.64"
     const val clikt = "2.6.0"
+    const val commonsCompress = "1.20"
     const val dependencyLicenseReport = "1.13"
     const val fernflower = "1.0.3"
     const val guava = "28.2-jre"

compress/build.gradle.kts

@@ -0,0 +1,25 @@
+plugins {
+    `maven-publish`
+    kotlin("jvm")
+}
+
+dependencies {
+    implementation(project(":common"))
+    implementation("org.apache.commons:commons-compress:${Versions.commonsCompress}")
+}
+
+publishing {
+    publications.create<MavenPublication>("maven") {
+        from(components["java"])
+
+        pom {
+            packaging = "jar"
+            name.set("OpenRS2 Compression")
+            description.set(
+                """
+                Provides headerless implementations of bzip2 and gzip.
+            """.trimIndent()
+            )
+        }
+    }
+}

compress/src/main/java/dev/openrs2/compress/bzip2/Bzip2.kt

@@ -0,0 +1,22 @@
+package dev.openrs2.compress.bzip2
+
+import dev.openrs2.common.io.SkipOutputStream
+import org.apache.commons.compress.compressors.bzip2.BZip2CompressorInputStream
+import org.apache.commons.compress.compressors.bzip2.BZip2CompressorOutputStream
+import java.io.ByteArrayInputStream
+import java.io.InputStream
+import java.io.OutputStream
+import java.io.SequenceInputStream
+
+object Bzip2 {
+    private const val BLOCK_SIZE = 1
+    private val HEADER = byteArrayOf('B'.toByte(), 'Z'.toByte(), 'h'.toByte(), ('0' + BLOCK_SIZE).toByte())
+
+    fun createHeaderlessInputStream(input: InputStream): InputStream {
+        return BZip2CompressorInputStream(SequenceInputStream(ByteArrayInputStream(HEADER), input))
+    }
+
+    fun createHeaderlessOutputStream(output: OutputStream): OutputStream {
+        return BZip2CompressorOutputStream(SkipOutputStream(output, HEADER.size.toLong()), BLOCK_SIZE)
+    }
+}

compress/src/main/java/dev/openrs2/compress/gzip/Gzip.kt

@@ -0,0 +1,21 @@
+package dev.openrs2.compress.gzip
+
+import dev.openrs2.common.io.SkipOutputStream
+import java.io.ByteArrayInputStream
+import java.io.InputStream
+import java.io.OutputStream
+import java.io.SequenceInputStream
+import java.util.zip.Deflater
+import java.util.zip.GZIPInputStream
+
+object Gzip {
+    private val HEADER = byteArrayOf(0x1F, 0x8B.toByte())
+
+    fun createHeaderlessInputStream(input: InputStream): InputStream {
+        return GZIPInputStream(SequenceInputStream(ByteArrayInputStream(HEADER), input))
+    }
+
+    fun createHeaderlessOutputStream(output: OutputStream, level: Int = Deflater.BEST_COMPRESSION): OutputStream {
+        return GzipLevelOutputStream(SkipOutputStream(output, HEADER.size.toLong()), level)
+    }
+}

compress/src/main/java/dev/openrs2/compress/gzip/GzipLevelOutputStream.kt

@@ -0,0 +1,10 @@
+package dev.openrs2.compress.gzip
+
+import java.io.OutputStream
+import java.util.zip.GZIPOutputStream
+
+class GzipLevelOutputStream(output: OutputStream, level: Int) : GZIPOutputStream(output) {
+    init {
+        def.setLevel(level)
+    }
+}

settings.gradle.kts

@@ -7,6 +7,7 @@ include(
     "asm",
     "bundler",
     "common",
+    "compress",
     "decompiler",
     "deob",
     "deob-annotations",