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// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_ARGUMENTS_H_
#define V8_ARGUMENTS_H_
namespace v8 {
namespace internal {
// Arguments provides access to runtime call parameters.
//
// It uses the fact that the instance fields of Arguments
// (length_, arguments_) are "overlayed" with the parameters
// (no. of parameters, and the parameter pointer) passed so
// that inside the C++ function, the parameters passed can
// be accessed conveniently:
//
// Object* Runtime_function(Arguments args) {
// ... use args[i] here ...
// }
class Arguments BASE_EMBEDDED {
public:
Object*& operator[] (int index) {
ASSERT(0 <= index && index < length_);
return arguments_[-index];
}
template <class S> Handle<S> at(int index) {
Object** value = &((*this)[index]);
// This cast checks that the object we're accessing does indeed have the
// expected type.
S::cast(*value);
return Handle<S>(reinterpret_cast<S**>(value));
}
// Get the total number of arguments including the receiver.
int length() const { return length_; }
private:
int length_;
Object** arguments_;
};
} } // namespace v8::internal
#endif // V8_ARGUMENTS_H_
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