freebsd-dev/contrib/bearssl/T0/TPointerExpr.cs
Simon J. Gerraty 0957b409a9 Add libbearssl
Disabled by default, used by loader and sbin/veriexec

Reviewed by:	emaste
Sponsored by:	Juniper Networks
Differential Revision: D16334
2019-02-26 05:59:22 +00:00

98 lines
2.4 KiB
C#

/*
* 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;
}
}