_ Git - BearSSL/blob - T0/TValue.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 using System.Collections.Generic;
  27
  28 /*
  29  * Each value is represented with a TValue structure. Integers use the 'x'
  30  * field, and 'ptr' is null; for pointers, the 'ptr' field is used, and the
  31  * 'x' is then an offset in the object represented by 'ptr'.
  32  */
  33
  34 struct TValue {
  35
  36         internal int x;
  37         internal TPointerBase ptr;
  38
  39         internal TValue(int x)
  40         {
  41                 this.x = x;
  42                 this.ptr = null;
  43         }
  44
  45         internal TValue(uint x)
  46         {
  47                 this.x = (int)x;
  48                 this.ptr = null;
  49         }
  50
  51         internal TValue(bool b)
  52         {
  53                 this.x = b ? -1 : 0;
  54                 this.ptr = null;
  55         }
  56
  57         internal TValue(int x, TPointerBase ptr)
  58         {
  59                 this.x = x;
  60                 this.ptr = ptr;
  61         }
  62
  63         /*
  64          * Convert this value to a boolean; integer 0 and null pointer are
  65          * 'false', other values are 'true'.
  66          */
  67         internal bool Bool {
  68                 get {
  69                         if (ptr == null) {
  70                                 return x != 0;
  71                         } else {
  72                                 return ptr.ToBool(this);
  73                         }
  74                 }
  75         }
  76
  77         /*
  78          * Get this value as an integer. Pointers cannot be converted to
  79          * integers.
  80          */
  81         internal int Int {
  82                 get {
  83                         if (ptr == null) {
  84                                 return x;
  85                         }
  86                         throw new Exception("not an integer: " + ToString());
  87                 }
  88         }
  89
  90         /*
  91          * Get this value as an unsigned integer. This is the integer
  92          * value, reduced modulo 2^32 in the 0..2^32-1 range.
  93          */
  94         internal uint UInt {
  95                 get {
  96                         return (uint)Int;
  97                 }
  98         }
  99
 100         /*
 101          * String format of integers uses decimal representation. For
 102          * pointers, this depends on the pointed-to value.
 103          */
 104         public override string ToString()
 105         {
 106                 if (ptr == null) {
 107                         return String.Format("{0}", x);
 108                 } else {
 109                         return ptr.ToString(this);
 110                 }
 111         }
 112
 113         /*
 114          * If this value is an XT, then execute it. Otherwise, an exception
 115          * is thrown.
 116          */
 117         internal void Execute(T0Comp ctx, CPU cpu)
 118         {
 119                 ToXT().Execute(ctx, cpu);
 120         }
 121
 122         /*
 123          * Convert this value to an XT. On failure, an exception is thrown.
 124          */
 125         internal TPointerXT ToXT()
 126         {
 127                 TPointerXT xt = ptr as TPointerXT;
 128                 if (xt == null) {
 129                         throw new Exception(
 130                                 "value is not an xt: " + ToString());
 131                 }
 132                 return xt;
 133         }
 134
 135         /*
 136          * Compare this value to another.
 137          */
 138         internal bool Equals(TValue v)
 139         {
 140                 if (x != v.x) {
 141                         return false;
 142                 }
 143                 if (ptr == v.ptr) {
 144                         return true;
 145                 }
 146                 if (ptr == null || v.ptr == null) {
 147                         return false;
 148                 }
 149                 return ptr.Equals(v.ptr);
 150         }
 151
 152         public static implicit operator TValue(bool val)
 153         {
 154                 return new TValue(val);
 155         }
 156
 157         public static implicit operator TValue(sbyte val)
 158         {
 159                 return new TValue((int)val);
 160         }
 161
 162         public static implicit operator TValue(byte val)
 163         {
 164                 return new TValue((int)val);
 165         }
 166
 167         public static implicit operator TValue(short val)
 168         {
 169                 return new TValue((int)val);
 170         }
 171
 172         public static implicit operator TValue(ushort val)
 173         {
 174                 return new TValue((int)val);
 175         }
 176
 177         public static implicit operator TValue(char val)
 178         {
 179                 return new TValue((int)val);
 180         }
 181
 182         public static implicit operator TValue(int val)
 183         {
 184                 return new TValue((int)val);
 185         }
 186
 187         public static implicit operator TValue(uint val)
 188         {
 189                 return new TValue((int)val);
 190         }
 191
 192         public static implicit operator bool(TValue v)
 193         {
 194                 return v.Bool;
 195         }
 196
 197         public static implicit operator sbyte(TValue v)
 198         {
 199                 return (sbyte)v.Int;
 200         }
 201
 202         public static implicit operator byte(TValue v)
 203         {
 204                 return (byte)v.Int;
 205         }
 206
 207         public static implicit operator short(TValue v)
 208         {
 209                 return (short)v.Int;
 210         }
 211
 212         public static implicit operator ushort(TValue v)
 213         {
 214                 return (ushort)v.Int;
 215         }
 216
 217         public static implicit operator char(TValue v)
 218         {
 219                 return (char)v.Int;
 220         }
 221
 222         public static implicit operator int(TValue v)
 223         {
 224                 return (int)v.Int;
 225         }
 226
 227         public static implicit operator uint(TValue v)
 228         {
 229                 return (uint)v.Int;
 230         }
 231 }