Initial import.

T0/TPointerExpr.cs

@@ -0,0 +1,97 @@
+/*
+ * 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;
+
+class TPointerExpr : TPointerBase {
+
+	string expr;
+	int min, max;
+
+	internal TPointerExpr(string expr, int min, int max)
+	{
+		this.expr = expr;
+		this.min = min;
+		this.max = max;
+	}
+
+	internal override bool ToBool(TValue vp)
+	{
+		throw new Exception("Cannot evaluate C-expr at compile time");
+	}
+
+	internal override string ToString(TValue vp)
+	{
+		return ToCExpr(vp.x);
+	}
+
+	internal string ToCExpr(int off)
+	{
+		if (off == 0) {
+			return expr;
+		} else if (off > 0) {
+			return String.Format(
+				"(uint32_t)({0}) + {1}", expr, off);
+		} else {
+			return String.Format(
+				"(uint32_t)({0}) - {1}", expr, -(long)off);
+		}
+	}
+
+	internal int GetMaxBitLength(int off)
+	{
+		long rmin = (long)min + off;
+		long rmax = (long)max + off;
+		int numBits = 1;
+		if (rmin < 0) {
+			numBits = Math.Max(numBits, BitLength(rmin));
+		}
+		if (rmax > 0) {
+			numBits = Math.Max(numBits, BitLength(rmax));
+		}
+		return Math.Min(numBits, 32);
+	}
+
+	/*
+	 * Get the minimal bit length of a value. This is for a signed
+	 * representation: the length includes a sign bit. Thus, the
+	 * returned value will be at least 1.
+	 */
+	static int BitLength(long v)
+	{
+		int num = 1;
+		if (v < 0) {
+			while (v != -1) {
+				num ++;
+				v >>= 1;
+			}
+		} else {
+			while (v != 0) {
+				num ++;
+				v >>= 1;
+			}
+		}
+		return num;
+	}
+}