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//
// PostOrPrefixOperator.cs:
//
// Author:
// Cesar Lopez Nataren (cesar@ciencias.unam.mx)
//
// (C) 2003, Cesar Lopez Nataren
//
//
// 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;
using System.Diagnostics;
using System.Reflection.Emit;
namespace Microsoft.JScript {
public class PostOrPrefixOperator : UnaryOp {
bool prefix;
public PostOrPrefixOperator (int operatorTok)
: base (null, null)
{
oper = (JSToken) operatorTok;
}
internal PostOrPrefixOperator (AST parent, AST operand, JSToken oper, bool prefix, Location location)
: base (parent, location)
{
this.operand = operand;
this.oper = oper;
this.prefix = prefix;
}
[DebuggerStepThroughAttribute]
[DebuggerHiddenAttribute]
public object EvaluatePostOrPrefix (ref object v)
{
double value = Convert.ToNumber (v);
v = value;
int oper = (int) this.oper;
if (oper % 2 == 1) /* prefix? */
return value + 1;
else
return value - 1;
}
internal override bool Resolve (Environment env)
{
return operand.Resolve (env);
}
internal override bool Resolve (Environment env, bool no_effect)
{
if (operand is Exp)
return ((Exp) operand).Resolve (env, no_effect);
else
return operand.Resolve (env);
}
internal override void Emit (EmitContext ec)
{
if (oper == JSToken.None)
operand.Emit (ec);
else {
ILGenerator ig = ec.ig;
Type post_prefix = typeof (PostOrPrefixOperator);
LocalBuilder post_prefix_local = ig.DeclareLocal (post_prefix);
LocalBuilder tmp_obj = ig.DeclareLocal (typeof (object));
switch (this.oper) {
case JSToken.Increment:
if (prefix)
ig.Emit (OpCodes.Ldc_I4_3);
else
ig.Emit (OpCodes.Ldc_I4_1);
break;
case JSToken.Decrement:
if (prefix)
ig.Emit (OpCodes.Ldc_I4_2);
else
ig.Emit (OpCodes.Ldc_I4_0);
break;
}
ig.Emit (OpCodes.Newobj, post_prefix.GetConstructor (new Type [] { typeof (int) }));
ig.Emit (OpCodes.Stloc, post_prefix_local);
Binary assign = null;
if (operand is Identifier)
((Identifier) operand).EmitLoad (ec);
else if (operand is Binary) {
Binary binary = operand as Binary;
binary.no_effect = false;
binary.assign = false;
assign = new Binary (binary.parent, binary.left, binary.right, binary.op, binary.location);
assign.assign = true;
assign.late_bind = true;
assign.no_effect = false;
if (binary.op == JSToken.LeftBracket || binary.op == JSToken.AccessField) {
binary.Emit (ec);
ig.Emit (OpCodes.Box, typeof (object));
} else
throw new NotImplementedException (String.Format ("Unhandled binary op {0}", operand));
} else {
Console.WriteLine ("PostOrPrefixOperator: prefix = {0}, oper = {1}, operand = {2}",
prefix, oper, operand.GetType ());
throw new NotImplementedException ();
}
ig.Emit (OpCodes.Stloc, tmp_obj);
ig.Emit (OpCodes.Ldloc, post_prefix_local);
ig.Emit (OpCodes.Ldloca_S, tmp_obj);
ig.Emit (OpCodes.Call, post_prefix.GetMethod ("EvaluatePostOrPrefix"));
//
// if does not appear as a global expression
//
if (prefix && !(parent is ScriptBlock)) {
ig.Emit (OpCodes.Dup);
ig.Emit (OpCodes.Stloc, tmp_obj);
}
if (operand is Identifier)
((Identifier) operand).EmitStore (ec);
else if (operand is Binary)
assign.Emit (ec);
else
throw new NotImplementedException ();
//
// If value will be used, load the
// temp var that holded the value
// before inc/dec was evaluated
//
if (!(parent is ScriptBlock || parent is FunctionDeclaration ||
parent is FunctionExpression || parent is Block))
ig.Emit (OpCodes.Ldloc, tmp_obj);
}
}
}
}
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