Differential D16334 Diff 55390 head/contrib/bearssl/T0/CodeElement.cs

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head/contrib/bearssl/T0/CodeElement.cs

				/*
				* 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;
				}
				}