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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
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 * This license is subject to the following condition:
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 * The above copyright notice and either this complete permission notice or at a
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package com.oracle.graal.python.lib;

import static com.oracle.graal.python.builtins.PythonBuiltinClassType.DeprecationWarning;
import static com.oracle.graal.python.builtins.PythonBuiltinClassType.TypeError;
import static com.oracle.graal.python.nodes.SpecialMethodNames.T___FLOAT__;

import com.oracle.graal.python.builtins.PythonBuiltinClassType;
import com.oracle.graal.python.builtins.modules.WarningsModuleBuiltins;
import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.floats.PFloat;
import com.oracle.graal.python.builtins.objects.type.SpecialMethodSlot;
import com.oracle.graal.python.nodes.ErrorMessages;
import com.oracle.graal.python.nodes.PNodeWithContext;
import com.oracle.graal.python.nodes.PRaiseNode;
import com.oracle.graal.python.nodes.call.special.CallUnaryMethodNode;
import com.oracle.graal.python.nodes.call.special.LookupSpecialMethodSlotNode;
import com.oracle.graal.python.nodes.classes.IsSubtypeNode;
import com.oracle.graal.python.nodes.object.GetClassNode;
import com.oracle.graal.python.nodes.object.IsBuiltinClassProfile;
import com.oracle.graal.python.nodes.util.CastToJavaDoubleNode;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.GenerateUncached;
import com.oracle.truffle.api.dsl.ImportStatic;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.Frame;
import com.oracle.truffle.api.frame.VirtualFrame;

/**
 * Equivalent of CPython's {@code PyFloat_AsDouble}. Converts the argument to a Java {@code double}
 * using its {@code __float__} special method. If not available, falls back to {@code __index__}
 * special method. Otherwise, raises {@code TypeError}. Can raise {@code OverflowError} when using
 * {@code __index__} and the returned integer wouldn't fit into double.
 */
@GenerateUncached
@ImportStatic(SpecialMethodSlot.class)
public abstract class PyFloatAsDoubleNode extends PNodeWithContext {
    public abstract double execute(Frame frame, Object object);

    @Specialization
    static double doDouble(double object) {
        return object;
    }

    @Specialization
    static double doPFloat(PFloat object) {
        return object.getValue();
    }

    @Specialization
    static double doInt(int object) {
        return object;
    }

    @Specialization
    static double doLong(long object) {
        return object;
    }

    @Specialization
    double doBoolean(boolean object) {
        return object ? 1.0 : 0.0;
    }

    // TODO When we implement casting native floats, this should cast them directly instead of
    // calling their __float__
    @Specialization(guards = {"!isDouble(object)", "!isInteger(object)", "!isBoolean(object)", "!isPFloat(object)"})
    static double doObject(VirtualFrame frame, Object object,
                    @Cached GetClassNode getClassNode,
                    @Cached(parameters = "Float") LookupSpecialMethodSlotNode lookup,
                    @Cached CallUnaryMethodNode call,
                    @Cached GetClassNode resultClassNode,
                    @Cached IsBuiltinClassProfile resultProfile,
                    @Cached IsSubtypeNode resultSubtypeNode,
                    @Cached PyIndexCheckNode indexCheckNode,
                    @Cached PyNumberIndexNode indexNode,
                    @Cached CastToJavaDoubleNode cast,
                    @Cached WarningsModuleBuiltins.WarnNode warnNode,
                    @Cached PRaiseNode raiseNode) {
        Object type = getClassNode.execute(object);
        Object floatDescr = lookup.execute(frame, type, object);
        if (floatDescr != PNone.NO_VALUE) {
            Object result = call.executeObject(frame, floatDescr, object);
            Object resultType = resultClassNode.execute(result);
            if (!resultProfile.profileClass(resultType, PythonBuiltinClassType.PFloat)) {
                if (!resultSubtypeNode.execute(resultType, PythonBuiltinClassType.PFloat)) {
                    throw raiseNode.raise(TypeError, ErrorMessages.RETURNED_NON_FLOAT, object, result);
                } else {
                    warnNode.warnFormat(frame, null, DeprecationWarning, 1,
                                    ErrorMessages.WARN_P_RETURNED_NON_P, object, T___FLOAT__, "float", result, "float");
                }
            }
            return cast.execute(result);
        }
        if (indexCheckNode.execute(object)) {
            Object index = indexNode.execute(frame, object);
            return cast.execute(index);
        }
        throw raiseNode.raise(TypeError, ErrorMessages.MUST_BE_REAL_NUMBER, object);
    }

    public static PyFloatAsDoubleNode create() {
        return PyFloatAsDoubleNodeGen.create();
    }

    public static PyFloatAsDoubleNode getUncached() {
        return PyFloatAsDoubleNodeGen.getUncached();
    }
}
