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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.dx.dex.code.form;
     18 
     19 import com.android.dx.dex.code.CstInsn;
     20 import com.android.dx.dex.code.DalvInsn;
     21 import com.android.dx.dex.code.InsnFormat;
     22 import com.android.dx.rop.code.RegisterSpec;
     23 import com.android.dx.rop.code.RegisterSpecList;
     24 import com.android.dx.rop.cst.Constant;
     25 import com.android.dx.rop.cst.CstMethodRef;
     26 import com.android.dx.rop.cst.CstType;
     27 import com.android.dx.util.AnnotatedOutput;
     28 
     29 /**
     30  * Instruction format {@code 3rc}. See the instruction format spec
     31  * for details.
     32  */
     33 public final class Form3rc extends InsnFormat {
     34     /** {@code non-null;} unique instance of this class */
     35     public static final InsnFormat THE_ONE = new Form3rc();
     36 
     37     /**
     38      * Constructs an instance. This class is not publicly
     39      * instantiable. Use {@link #THE_ONE}.
     40      */
     41     private Form3rc() {
     42         // This space intentionally left blank.
     43     }
     44 
     45     /** {@inheritDoc} */
     46     @Override
     47     public String insnArgString(DalvInsn insn) {
     48         RegisterSpecList regs = insn.getRegisters();
     49         int size = regs.size();
     50         StringBuilder sb = new StringBuilder(30);
     51 
     52         sb.append("{");
     53 
     54         switch (size) {
     55             case 0: {
     56                 // Nothing to do.
     57                 break;
     58             }
     59             case 1: {
     60                 sb.append(regs.get(0).regString());
     61                 break;
     62             }
     63             default: {
     64                 RegisterSpec lastReg = regs.get(size - 1);
     65                 if (lastReg.getCategory() == 2) {
     66                     /*
     67                      * Add one to properly represent a list-final
     68                      * category-2 register.
     69                      */
     70                     lastReg = lastReg.withOffset(1);
     71                 }
     72 
     73                 sb.append(regs.get(0).regString());
     74                 sb.append("..");
     75                 sb.append(lastReg.regString());
     76             }
     77         }
     78 
     79         sb.append("}, ");
     80         sb.append(cstString(insn));
     81 
     82         return sb.toString();
     83     }
     84 
     85     /** {@inheritDoc} */
     86     @Override
     87     public String insnCommentString(DalvInsn insn, boolean noteIndices) {
     88         if (noteIndices) {
     89             return cstComment(insn);
     90         } else {
     91             return "";
     92         }
     93     }
     94 
     95     /** {@inheritDoc} */
     96     @Override
     97     public int codeSize() {
     98         return 3;
     99     }
    100 
    101     /** {@inheritDoc} */
    102     @Override
    103     public boolean isCompatible(DalvInsn insn) {
    104         if (!(insn instanceof CstInsn)) {
    105             return false;
    106         }
    107 
    108         CstInsn ci = (CstInsn) insn;
    109         int cpi = ci.getIndex();
    110 
    111         if (! unsignedFitsInShort(cpi)) {
    112             return false;
    113         }
    114 
    115         Constant cst = ci.getConstant();
    116         if (!((cst instanceof CstMethodRef) ||
    117               (cst instanceof CstType))) {
    118             return false;
    119         }
    120 
    121         RegisterSpecList regs = ci.getRegisters();
    122         int sz = regs.size();
    123 
    124         if (sz == 0) {
    125             return true;
    126         }
    127 
    128         int first = regs.get(0).getReg();
    129         int next = first;
    130 
    131         if (!unsignedFitsInShort(first)) {
    132             return false;
    133         }
    134 
    135         for (int i = 0; i < sz; i++) {
    136             RegisterSpec one = regs.get(i);
    137             if (one.getReg() != next) {
    138                 return false;
    139             }
    140             next += one.getCategory();
    141         }
    142 
    143         return unsignedFitsInByte(next - first);
    144     }
    145 
    146     /** {@inheritDoc} */
    147     @Override
    148     public InsnFormat nextUp() {
    149         return null;
    150     }
    151 
    152     /** {@inheritDoc} */
    153     @Override
    154     public void writeTo(AnnotatedOutput out, DalvInsn insn) {
    155         RegisterSpecList regs = insn.getRegisters();
    156         int sz = regs.size();
    157         int cpi = ((CstInsn) insn).getIndex();
    158         int firstReg;
    159         int count;
    160 
    161         if (sz == 0) {
    162             firstReg = 0;
    163             count = 0;
    164         } else {
    165             int lastReg = regs.get(sz - 1).getNextReg();
    166             firstReg = regs.get(0).getReg();
    167             count = lastReg - firstReg;
    168         }
    169 
    170         write(out,
    171               opcodeUnit(insn, count),
    172               (short) cpi,
    173               (short) firstReg);
    174     }
    175 }
    176