From 76be350b3c54ea88cc1a95b5cf0d1db153f2edb3 Mon Sep 17 00:00:00 2001
From: jeff
Date: Sun, 3 Aug 2014 11:16:33 -0400
Subject: fixed bugs with saving mappings got argument renaming to work

---
 .../enigma/bytecode/MethodParametersAttribute.java | 46 +++++++++++++++-------
 1 file changed, 31 insertions(+), 15 deletions(-)

(limited to 'src/cuchaz/enigma/bytecode/MethodParametersAttribute.java')

diff --git a/src/cuchaz/enigma/bytecode/MethodParametersAttribute.java b/src/cuchaz/enigma/bytecode/MethodParametersAttribute.java
index 0b29403..baf1ac1 100644
--- a/src/cuchaz/enigma/bytecode/MethodParametersAttribute.java
+++ b/src/cuchaz/enigma/bytecode/MethodParametersAttribute.java
@@ -13,24 +13,45 @@ package cuchaz.enigma.bytecode;
 import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.List;
 
 import javassist.bytecode.AttributeInfo;
 import javassist.bytecode.ConstPool;
+import javassist.bytecode.MethodInfo;
 
 public class MethodParametersAttribute extends AttributeInfo
 {
-	public MethodParametersAttribute( ConstPool pool, int attributeNameIndex, List<Integer> parameterNameIndices )
+	private MethodParametersAttribute( ConstPool pool, List<Integer> parameterNameIndices )
 	{
-		super( pool, "MethodParameters", writeStruct( attributeNameIndex, parameterNameIndices ) );
+		super( pool, "MethodParameters", writeStruct( parameterNameIndices ) );
 	}
 	
-	private static byte[] writeStruct( int attributeNameIndex, List<Integer> parameterNameIndices )
+	public static void updateClass( MethodInfo info, List<String> names )
 	{
-		// JVM Spec says the struct looks like this:
+		// add the names to the class const pool
+		ConstPool constPool = info.getConstPool();
+		List<Integer> parameterNameIndices = new ArrayList<Integer>();
+		for( String name : names )
+		{
+			if( name != null )
+			{
+				parameterNameIndices.add( constPool.addUtf8Info( name ) );
+			}
+			else
+			{
+				parameterNameIndices.add( 0 );
+			}
+		}
+		
+		// add the attribute to the method
+		info.addAttribute( new MethodParametersAttribute( constPool, parameterNameIndices ) );
+	}
+	
+	private static byte[] writeStruct( List<Integer> parameterNameIndices )
+	{
+		// JVM 8 Spec says the struct looks like this:
 		// http://cr.openjdk.java.net/~mr/se/8/java-se-8-fr-spec-01/java-se-8-jvms-fr-diffs.pdf
-		// uint16 name_index -> points to UTF8 entry in constant pool that says "MethodParameters"
-		// uint32 length -> length of this struct, minus 6 bytes (ie, length of num_params and parameter array)
 		// uint8 num_params
 		// for each param:
 		//    uint16 name_index -> points to UTF8 entry in constant pool, or 0 for no entry
@@ -43,20 +64,13 @@ public class MethodParametersAttribute extends AttributeInfo
 		// the writeShort(), writeByte() methods will read 16,8 low-order bits from the int argument
 		// as long as the int argument is in range of the unsigned short/byte type, it will be written as an unsigned short/byte
 		// if the int is out of range, the byte stream won't look the way we want and weird things will happen
+		final int SIZEOF_UINT8 = 1;
 		final int SIZEOF_UINT16 = 2;
 		final int MAX_UINT8 = ( 1 << 8 ) - 1;
 		final int MAX_UINT16 = ( 1 << 16 ) - 1;
-		final long MAX_UINT32 = ( 1 << 32 ) - 1;
 		
 		try
 		{
-			assert( attributeNameIndex >= 0 && attributeNameIndex <= MAX_UINT16 );
-			out.writeShort( attributeNameIndex );
-			
-			long length = SIZEOF_UINT16 + parameterNameIndices.size()*( SIZEOF_UINT16 + SIZEOF_UINT16 );
-			assert( length >= 0 && length <= MAX_UINT32 );
-			out.writeInt( (int)length );
-			
 			assert( parameterNameIndices.size() >= 0 && parameterNameIndices.size() <= MAX_UINT8 );
 			out.writeByte( parameterNameIndices.size() );
 			
@@ -70,7 +84,9 @@ public class MethodParametersAttribute extends AttributeInfo
 			}
 			
 			out.close();
-			return buf.toByteArray();
+			byte[] data = buf.toByteArray();
+			assert( data.length == SIZEOF_UINT8 + parameterNameIndices.size()*( SIZEOF_UINT16 + SIZEOF_UINT16 ) );
+			return data;
 		}
 		catch( IOException ex )
 		{
-- 
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