98 lines
2.4 KiB
C#
98 lines
2.4 KiB
C#
/*
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* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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using System;
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class TPointerExpr : TPointerBase {
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string expr;
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int min, max;
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internal TPointerExpr(string expr, int min, int max)
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{
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this.expr = expr;
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this.min = min;
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this.max = max;
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}
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internal override bool ToBool(TValue vp)
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{
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throw new Exception("Cannot evaluate C-expr at compile time");
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}
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internal override string ToString(TValue vp)
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{
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return ToCExpr(vp.x);
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}
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internal string ToCExpr(int off)
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{
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if (off == 0) {
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return expr;
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} else if (off > 0) {
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return String.Format(
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"(uint32_t)({0}) + {1}", expr, off);
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} else {
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return String.Format(
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"(uint32_t)({0}) - {1}", expr, -(long)off);
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}
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}
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internal int GetMaxBitLength(int off)
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{
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long rmin = (long)min + off;
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long rmax = (long)max + off;
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int numBits = 1;
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if (rmin < 0) {
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numBits = Math.Max(numBits, BitLength(rmin));
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}
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if (rmax > 0) {
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numBits = Math.Max(numBits, BitLength(rmax));
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}
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return Math.Min(numBits, 32);
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}
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/*
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* Get the minimal bit length of a value. This is for a signed
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* representation: the length includes a sign bit. Thus, the
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* returned value will be at least 1.
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*/
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static int BitLength(long v)
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{
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int num = 1;
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if (v < 0) {
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while (v != -1) {
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num ++;
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v >>= 1;
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}
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} else {
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while (v != 0) {
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num ++;
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v >>= 1;
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}
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}
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return num;
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}
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}
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