LibJS: Add Value::to_size_t()

abyesilyurt · May 1, 2020 · 65dbe17 · 65dbe17
1 parent 62671be
commit 65dbe17
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Showing 3 changed files with 13 additions and 4 deletions.
diff --git a/Libraries/LibJS/Runtime/FunctionPrototype.cpp b/Libraries/LibJS/Runtime/FunctionPrototype.cpp
@@ -71,10 +71,8 @@ Value FunctionPrototype::apply(Interpreter& interpreter)
  return interpreter.call(function, this_arg);
  if (!arg_array.is_object())
  return interpreter.throw_exception<TypeError>("argument array must be an object");
- size_t length = 0;
  auto length_property = arg_array.as_object().get("length");
- if (!length_property.is_empty())
- length = length_property.to_number().to_i32();
+ auto length = length_property.to_size_t();
  MarkedValueList arguments(interpreter.heap());
  for (size_t i = 0; i < length; ++i) {
  auto element = arg_array.as_object().get(String::number(i));

diff --git a/Libraries/LibJS/Runtime/Value.cpp b/Libraries/LibJS/Runtime/Value.cpp
@@ -183,6 +183,16 @@ double Value::to_double() const
  return to_number().as_double();
 }
 
+size_t Value::to_size_t() const
+{
+ if (is_empty())
+ return 0;
+ auto number = to_number();
+ if (number.is_nan() || number.as_double() <= 0)
+ return 0;
+ return min(number.to_i32(), (i32)pow(2, 53) - 1);
+}
+
 Value greater_than(Interpreter&, Value lhs, Value rhs)
 {
  return Value(lhs.to_number().as_double() > rhs.to_number().as_double());
@@ -313,7 +323,7 @@ Value mod(Interpreter&, Value lhs, Value rhs)
 
  double index = lhs.to_number().as_double();
  double period = rhs.to_number().as_double();
- double trunc = (double)(i32) (index / period);
+ double trunc = (double)(i32)(index / period);
 
  return Value(index - trunc * period);
 }

diff --git a/Libraries/LibJS/Runtime/Value.h b/Libraries/LibJS/Runtime/Value.h
@@ -162,6 +162,7 @@ class Value {
  Value to_number() const;
  i32 to_i32() const;
  double to_double() const;
+ size_t to_size_t() const;
  Value to_primitive(Interpreter&) const;
 
  Object* to_object(Heap&) const;