xref: /freebsd/contrib/bearssl/T0/CodeElementJump.cs (revision 2aaf9152a852aba9eb2036b95f4948ee77988826)
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 
CodeElementJump(uint jumpType)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 
GetLength(bool oneByteCode)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 
SetJumpTarget(CodeElement target)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 
Encode(BlobWriter bw, bool oneByteCode)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 }
98