_ Git - BearSSL/blob - T0/CodeElementJump.cs

   1 /*
   2  * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 using System;
  26
  27 class CodeElementJump : CodeElement {
  28
  29         uint jumpType;
  30         CodeElement target;
  31
  32         internal CodeElementJump(uint jumpType)
  33         {
  34                 this.jumpType = jumpType;
  35         }
  36
  37         /* obsolete
  38         internal override int Length {
  39                 get {
  40                         int len = Encode7EUnsigned(jumpType, null);
  41                         int joff = JumpOff;
  42                         if (joff == Int32.MinValue) {
  43                                 len ++;
  44                         } else {
  45                                 len += Encode7ESigned(joff, null);
  46                         }
  47                         return len;
  48                 }
  49         }
  50         */
  51
  52         internal override int GetLength(bool oneByteCode)
  53         {
  54                 int len = oneByteCode ? 1 : Encode7EUnsigned(jumpType, null);
  55                 int joff = JumpOff;
  56                 if (joff == Int32.MinValue) {
  57                         len ++;
  58                 } else {
  59                         len += Encode7ESigned(joff, null);
  60                 }
  61                 return len;
  62         }
  63
  64         internal override void SetJumpTarget(CodeElement target)
  65         {
  66                 this.target = target;
  67         }
  68
  69         int JumpOff {
  70                 get {
  71                         if (target == null || Address < 0 || target.Address < 0)
  72                         {
  73                                 return Int32.MinValue;
  74                         } else {
  75                                 return target.Address - (Address + LastLength);
  76                         }
  77                 }
  78         }
  79
  80         internal override int Encode(BlobWriter bw, bool oneByteCode)
  81         {
  82                 if (bw == null) {
  83                         return GetLength(oneByteCode);
  84                 }
  85                 int len;
  86                 if (oneByteCode) {
  87                         len = EncodeOneByte(jumpType, bw);
  88                 } else {
  89                         len = Encode7EUnsigned(jumpType, bw);
  90                 }
  91                 int joff = JumpOff;
  92                 if (joff == Int32.MinValue) {
  93                         throw new Exception("Unresolved addresses");
  94                 }
  95                 return len + Encode7ESigned(joff, bw);
  96         }
  97 }