Add support for @ operator to PostfixEvaluator

R=mark at http://breakpad.appspot.com/349002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@923 4c0a9323-5329-0410-9bdc-e9ce6186880e

3 files changed, 17 insertions, 6 deletions

diff --git a/src/processor/postfix_evaluator-inl.h b/src/processor/postfix_evaluator-inl.h
index b24f092c..22faf7b2 100644
--- a/src/processor/postfix_evaluator-inl.h
+++ b/src/processor/postfix_evaluator-inl.h
@@ -83,7 +83,8 @@ bool PostfixEvaluator<ValueType>::EvaluateInternal(
       BINARY_OP_SUBTRACT,
       BINARY_OP_MULTIPLY,
       BINARY_OP_DIVIDE_QUOTIENT,
-      BINARY_OP_DIVIDE_MODULUS
+      BINARY_OP_DIVIDE_MODULUS,
+      BINARY_OP_ALIGN
     };
 
     BinaryOperation operation = BINARY_OP_NONE;
@@ -97,6 +98,8 @@ bool PostfixEvaluator<ValueType>::EvaluateInternal(
       operation = BINARY_OP_DIVIDE_QUOTIENT;
     else if (token == "%")
       operation = BINARY_OP_DIVIDE_MODULUS;
+    else if (token == "@")
+      operation = BINARY_OP_ALIGN;
 
     if (operation != BINARY_OP_NONE) {
       // Get the operands.
@@ -126,6 +129,10 @@ bool PostfixEvaluator<ValueType>::EvaluateInternal(
         case BINARY_OP_DIVIDE_MODULUS:
           result = operand1 % operand2;
           break;
+        case BINARY_OP_ALIGN:
+          result =
+            operand1 & (reinterpret_cast<ValueType>(-1) ^ (operand2 - 1));
+          break;
         case BINARY_OP_NONE:
           // This will not happen, but compilers will want a default or
           // BINARY_OP_NONE case.
diff --git a/src/processor/postfix_evaluator.h b/src/processor/postfix_evaluator.h
index 24807551..35f79f76 100644
--- a/src/processor/postfix_evaluator.h
+++ b/src/processor/postfix_evaluator.h
@@ -44,10 +44,12 @@
 // either literal values suitable for ValueType, or constants or variables,
 // which reference the dictionary.  The supported binary operators are +
 // (addition), - (subtraction), * (multiplication), / (quotient of division),
-// and % (modulus of division).  The unary ^ (dereference) operator is also
-// provided.  These operators allow any operand to be either a literal
-// value, constant, or variable.  Assignment (=) of any type of operand into
-// a variable is also supported.
+// % (modulus of division), and @ (data alignment). The alignment operator (@)
+// accepts a value and an alignment size, and produces a result that is a
+// multiple of the alignment size by truncating the input value.
+// The unary ^ (dereference) operator is also provided.  These operators
+// allow any operand to be either a literal value, constant, or variable.
+// Assignment (=) of any type of operand into a variable is also supported.
 //
 // The dictionary is provided as a map with string keys.  Keys beginning
 // with the '$' character are treated as variables.  All other keys are
diff --git a/src/processor/postfix_evaluator_unittest.cc b/src/processor/postfix_evaluator_unittest.cc
index 0c2d8ece..427ee505 100644
--- a/src/processor/postfix_evaluator_unittest.cc
+++ b/src/processor/postfix_evaluator_unittest.cc
@@ -148,7 +148,8 @@ static bool RunTests() {
     { "$rSub 9 6 - =",     true },   // $rSub = 9 - 6 = 3
     { "$rDivQ 9 6 / =",    true },   // $rDivQ = 9 / 6 = 1
     { "$rDivM 9 6 % =",    true },   // $rDivM = 9 % 6 = 3
-    { "$rDeref 9 ^ =",     true }    // $rDeref = ^9 = 10 (FakeMemoryRegion)
+    { "$rDeref 9 ^ =",     true },   // $rDeref = ^9 = 10 (FakeMemoryRegion)
+    { "$rAlign 36 8 @ =",  true },   // $rAlign = 36 @ 8
   };
   map<string, unsigned int> validate_data_0;
   validate_data_0["$rAdd"]   = 8;
@@ -158,6 +159,7 @@ static bool RunTests() {
   validate_data_0["$rDivQ"]  = 1;
   validate_data_0["$rDivM"]  = 3;
   validate_data_0["$rDeref"] = 10;
+  validate_data_0["$rAlign"] = 32;
 
   // The second test set simulates a couple of MSVC program strings.
   // The data is fudged a little bit because the tests use FakeMemoryRegion