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Diffstat (limited to 'T0/CodeElement.cs')
-rw-r--r-- | T0/CodeElement.cs | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/T0/CodeElement.cs b/T0/CodeElement.cs new file mode 100644 index 0000000000000..471a61f903f25 --- /dev/null +++ b/T0/CodeElement.cs @@ -0,0 +1,100 @@ +/* + * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +using System; + +abstract class CodeElement { + + internal int Address { get; set; } + + internal int LastLength { get; set; } + + // internal abstract int Length { get; } + + internal CodeElement() + { + Address = -1; + } + + internal virtual void SetJumpTarget(CodeElement target) + { + throw new Exception("Code element accepts no target"); + } + + internal abstract int GetLength(bool oneByteCode); + + internal abstract int Encode(BlobWriter bw, bool oneByteCode); + + internal static int EncodeOneByte(uint val, BlobWriter bw) + { + if (val > 255) { + throw new Exception(string.Format( + "Cannot encode '{0}' over one byte", val)); + } + bw.Append((byte)val); + return 1; + } + + internal static int Encode7EUnsigned(uint val, BlobWriter bw) + { + int len = 1; + for (uint w = val; w >= 0x80; w >>= 7) { + len ++; + } + if (bw != null) { + for (int k = (len - 1) * 7; k >= 0; k -= 7) { + int x = (int)(val >> k) & 0x7F; + if (k > 0) { + x |= 0x80; + } + bw.Append((byte)x); + } + } + return len; + } + + internal static int Encode7ESigned(int val, BlobWriter bw) + { + int len = 1; + if (val < 0) { + for (int w = val; w < -0x40; w >>= 7) { + len ++; + } + } else { + for (int w = val; w >= 0x40; w >>= 7) { + len ++; + } + } + if (bw != null) { + for (int k = (len - 1) * 7; k >= 0; k -= 7) { + int x = (int)(val >> k) & 0x7F; + if (k > 0) { + x |= 0x80; + } + bw.Append((byte)x); + } + } + return len; + } +} |