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69 lines
2.5 KiB
69 lines
2.5 KiB
package dev.openrs2.deob.ast.transform
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import com.github.javaparser.ast.CompilationUnit
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import com.github.javaparser.ast.Node
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import com.github.javaparser.ast.expr.BinaryExpr
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import com.github.javaparser.ast.expr.IntegerLiteralExpr
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import dev.openrs2.deob.ast.util.createLong
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import dev.openrs2.deob.ast.util.isIntegerOrLongLiteral
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import dev.openrs2.deob.ast.util.walk
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class BitMaskTransformer : Transformer() {
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override fun transform(unit: CompilationUnit) {
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unit.walk(Node.TreeTraversal.POSTORDER) { expr: BinaryExpr ->
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val shiftOp = expr.operator
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val left = expr.left
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val shamtExpr = expr.right
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if (!SHIFT_OPS.contains(shiftOp) || !left.isBinaryExpr || !shamtExpr.isIntegerLiteralExpr) {
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return@walk
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}
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val bitwiseExpr = left.asBinaryExpr()
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val bitwiseOp = bitwiseExpr.operator
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val argExpr = bitwiseExpr.left
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var maskExpr = bitwiseExpr.right
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if (!BITWISE_OPS.contains(bitwiseOp) || !maskExpr.isIntegerOrLongLiteral()) {
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return@walk
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}
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val shamt = shamtExpr.asIntegerLiteralExpr().asInt()
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if (maskExpr.isIntegerLiteralExpr) {
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var mask = maskExpr.asIntegerLiteralExpr().asInt()
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mask = when (shiftOp) {
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BinaryExpr.Operator.SIGNED_RIGHT_SHIFT -> mask shr shamt
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BinaryExpr.Operator.UNSIGNED_RIGHT_SHIFT -> mask ushr shamt
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else -> throw IllegalStateException()
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}
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maskExpr = IntegerLiteralExpr(mask)
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} else {
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var mask = maskExpr.asLongLiteralExpr().asLong()
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mask = when (shiftOp) {
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BinaryExpr.Operator.SIGNED_RIGHT_SHIFT -> mask shr shamt
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BinaryExpr.Operator.UNSIGNED_RIGHT_SHIFT -> mask ushr shamt
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else -> throw IllegalStateException()
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}
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maskExpr = createLong(mask)
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}
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expr.replace(BinaryExpr(BinaryExpr(argExpr.clone(), shamtExpr.clone(), shiftOp), maskExpr, bitwiseOp))
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}
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}
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companion object {
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private val SHIFT_OPS = setOf(
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BinaryExpr.Operator.SIGNED_RIGHT_SHIFT,
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BinaryExpr.Operator.UNSIGNED_RIGHT_SHIFT
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)
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private val BITWISE_OPS = setOf(
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BinaryExpr.Operator.BINARY_AND,
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BinaryExpr.Operator.BINARY_OR,
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BinaryExpr.Operator.XOR
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)
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}
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}
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