Open-source multiplayer game server compatible with the RuneScape client
https://www.openrs2.org/
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56 lines
1.7 KiB
56 lines
1.7 KiB
package dev.openrs2.deob.transform
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import com.github.michaelbull.logging.InlineLogger
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import dev.openrs2.asm.InsnMatcher
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import dev.openrs2.asm.classpath.ClassPath
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import dev.openrs2.asm.classpath.Library
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import dev.openrs2.asm.intConstant
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import dev.openrs2.asm.toAbstractInsnNode
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import dev.openrs2.asm.transform.Transformer
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import org.objectweb.asm.Opcodes
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import org.objectweb.asm.tree.ClassNode
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import org.objectweb.asm.tree.MethodNode
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import javax.inject.Singleton
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@Singleton
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class BitShiftTransformer : Transformer() {
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private var simplified = 0
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override fun preTransform(classPath: ClassPath) {
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simplified = 0
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}
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override fun transformCode(
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classPath: ClassPath,
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library: Library,
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clazz: ClassNode,
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method: MethodNode
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): Boolean {
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for (match in CONST_SHIFT_MATCHER.match(method)) {
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val push = match[0]
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val bits = push.intConstant!!
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val opcode = match[1].opcode
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val mask = if (opcode in LONG_SHIFTS) 63 else 31
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val simplifiedBits = bits and mask
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if (bits != simplifiedBits) {
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method.instructions[push] = simplifiedBits.toAbstractInsnNode()
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simplified++
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}
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}
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return false
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}
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override fun postTransform(classPath: ClassPath) {
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logger.info { "Simplified $simplified bit shifts" }
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}
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private companion object {
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private val logger = InlineLogger()
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private val CONST_SHIFT_MATCHER =
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InsnMatcher.compile("(ICONST | BIPUSH | SIPUSH | LDC) (ISHL | ISHR | IUSHR | LSHL | LSHR | LUSHR)")
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private val LONG_SHIFTS = setOf(Opcodes.LSHL, Opcodes.LSHR, Opcodes.LUSHR)
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}
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}
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