modules/tool-classfile/src/main/java/net/multiphasicapps/classfile/LocalVariableTable.java

   1 // -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
   2 // ---------------------------------------------------------------------------
   3 // Multi-Phasic Applications: SquirrelJME
   4 //     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
   5 // ---------------------------------------------------------------------------
   6 // SquirrelJME is under the GNU General Public License v3+, or later.
   7 // See license.mkd for licensing and copyright information.
   8 // ---------------------------------------------------------------------------
   9
  10 package net.multiphasicapps.classfile;
  11
  12 import cc.squirreljme.runtime.cldc.debug.Debugging;
  13 import cc.squirreljme.runtime.cldc.util.UnmodifiableIterator;
  14 import java.io.DataInputStream;
  15 import java.io.IOException;
  16 import java.util.Arrays;
  17 import java.util.Iterator;
  18
  19 /**
  20  * Represents a local variable table.
  21  *
  22  * @since 2022/09/21
  23  */
  24 public final class LocalVariableTable
  25         implements Iterable<LocalVariableInfo>
  26 {
  27         /** The entries within the table. */
  28         private final LocalVariableInfo[] _entries;
  29
  30         /**
  31          * Initializes the local variable table.
  32          *
  33          * @param __vars the variables to use.
  34          * @throws NullPointerException On null arguments.
  35          * @since 2022/09/23
  36          */
  37         public LocalVariableTable(LocalVariableInfo... __vars)
  38                 throws NullPointerException
  39         {
  40                 if (__vars == null)
  41                         throw new NullPointerException("NARG");
  42
  43                 __vars = __vars.clone();
  44                 for (LocalVariableInfo var : __vars)
  45                         if (var == null)
  46                                 throw new NullPointerException("NARG");
  47
  48                 this._entries = __vars;
  49         }
  50
  51         /**
  52          * {@inheritDoc}
  53          * @since 2022/09/23
  54          */
  55         @Override
  56         public boolean equals(Object __o)
  57         {
  58                 if (this == __o)
  59                         return true;
  60                 if (!(__o instanceof LocalVariableTable))
  61                         return false;
  62
  63                 LocalVariableTable that = (LocalVariableTable)__o;
  64                 return Arrays.equals(this._entries, that._entries);
  65         }
  66
  67         /**
  68          * {@inheritDoc}
  69          * @since 2022/09/23
  70          */
  71         @Override
  72         public int hashCode()
  73         {
  74                 return Arrays.asList(this._entries).hashCode();
  75         }
  76
  77         /**
  78          * {@inheritDoc}
  79          * @since 2022/09/23
  80          */
  81         @Override
  82         public Iterator<LocalVariableInfo> iterator()
  83         {
  84                 return UnmodifiableIterator.of(this._entries);
  85         }
  86
  87         /**
  88          * Returns the number of entries within.
  89          *
  90          * @return The size of the table.
  91          * @since 2022/09/23
  92          */
  93         public int size()
  94         {
  95                 return this._entries.length;
  96         }
  97
  98         /**
  99          * {@inheritDoc}
 100          * @since 2022/09/23
 101          */
 102         @Override
 103         public String toString()
 104         {
 105                 return Arrays.asList(this._entries).toString();
 106         }
 107
 108         /**
 109          * Parses the local variable tables.
 110          *
 111          * @param __pool The pool used.
 112          * @param __attrs The attributes to read from.
 113          * @return The resultant local variable table.
 114          * @throws IOException On read errors.
 115          * @throws NullPointerException On null arguments.
 116          * @since 2022/09/21
 117          */
 118         public static LocalVariableTable parse(Pool __pool,
 119                 AttributeTable __attrs)
 120                 throws IOException, NullPointerException
 121         {
 122                 if (__pool == null || __attrs == null)
 123                         throw new NullPointerException("NARG");
 124
 125                 // Get the table if it exists
 126                 Attribute attr = __attrs.get("LocalVariableTable");
 127                 if (attr == null)
 128                         return new LocalVariableTable();
 129
 130                 // Parse data
 131                 try (DataInputStream in = attr.open())
 132                 {
 133                         // How many?
 134                         int count = in.readUnsignedShort();
 135
 136                         // Setup and load each one
 137                         LocalVariableInfo[] result = new LocalVariableInfo[count];
 138                         for (int i = 0; i < count; i++)
 139                                 result[i] = new LocalVariableInfo(
 140                                         in.readUnsignedShort(),
 141                                         in.readUnsignedShort(),
 142                                         new FieldName(__pool.require(UTFConstantEntry.class,
 143                                                 in.readUnsignedShort()).toString()),
 144                                         new FieldDescriptor(__pool.require(UTFConstantEntry.class,
 145                                                 in.readUnsignedShort()).toString()),
 146                                         in.readUnsignedShort());
 147
 148                         return new LocalVariableTable(result);
 149                 }
 150         }
 151 }