forked from openrs2/openrs2
parent
8f3591670b
commit
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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.Expression |
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import com.github.javaparser.ast.expr.UnaryExpr |
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import dev.openrs2.deob.ast.util.walk |
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class IdentityTransformer : 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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@Suppress("NON_EXHAUSTIVE_WHEN") |
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when (expr.operator) { |
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BinaryExpr.Operator.PLUS -> { |
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if (isZero(expr.left)) { |
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// 0 + x => x |
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expr.replace(expr.right) |
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} else if (isZero(expr.right)) { |
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// x + 0 => x |
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expr.replace(expr.left) |
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} |
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} |
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BinaryExpr.Operator.MINUS -> { |
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if (isZero(expr.left)) { |
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// 0 - x => -x |
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expr.replace(UnaryExpr(expr.right, UnaryExpr.Operator.MINUS)) |
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} else if (isZero(expr.right)) { |
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// x - 0 => x |
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expr.replace(expr.left) |
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} |
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} |
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BinaryExpr.Operator.MULTIPLY -> { |
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if (isOne(expr.left)) { |
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// 1 * x => x |
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expr.replace(expr.right) |
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} else if (isOne(expr.right)) { |
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// x * 1 => x |
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expr.replace(expr.left) |
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} |
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} |
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} |
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} |
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} |
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|
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companion object { |
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private fun isZero(expr: Expression): Boolean { |
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return when { |
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expr.isIntegerLiteralExpr -> expr.asIntegerLiteralExpr().asNumber() == 0 |
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expr.isLongLiteralExpr -> expr.asLongLiteralExpr().asNumber() == 0L |
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else -> false |
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} |
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} |
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|
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private fun isOne(expr: Expression): Boolean { |
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return when { |
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expr.isIntegerLiteralExpr -> expr.asIntegerLiteralExpr().asNumber() == 1 |
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expr.isLongLiteralExpr -> expr.asLongLiteralExpr().asNumber() == 1L |
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else -> false |
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} |
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} |
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} |
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} |
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