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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * The Universal Permissive License (UPL), Version 1.0
 *
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 * person obtaining a copy of this software, associated documentation and/or
 * data (collectively the "Software"), free of charge and under any and all
 * copyright rights in the Software, and any and all patent rights owned or
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 * unmodified Software as contributed to or provided by such licensor, or (ii)
 * the Larger Works (as defined below), to deal in both
 *
 * (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
 * is contributed by such licensors),
 *
 * without restriction, including without limitation the rights to copy, create
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
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 * This license is subject to the following condition:
 *
 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
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package com.oracle.graal.python.lib;

import static com.oracle.graal.python.builtins.PythonBuiltinClassType.OverflowError;

import com.oracle.graal.python.builtins.PythonBuiltinClassType;
import com.oracle.graal.python.builtins.objects.PNone;
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.util.CannotCastException;
import com.oracle.graal.python.nodes.util.CastToJavaIntExactNode;
import com.oracle.graal.python.nodes.util.CastToJavaIntLossyNode;
import com.oracle.graal.python.runtime.exception.PException;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Cached.Shared;
import com.oracle.truffle.api.dsl.GenerateUncached;
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 PyNumber_AsSize} function. Converts the argument into integer (our
 * equivalent of {@code Py_ssize_t}) using its {@code __index__} method. Raises a {@code TypeError}
 * if the argument is not convertible to integer. Overflow behavior depends on the execute method
 * used:
 * <ul>
 * <li>{@link #executeLossy(Frame, Object)} clamps the value to maximal/minimal integer (equivalent
 * of passing {@code NULL} in CPython).
 * <li>{@link #executeExact(Frame, Object)} raises {@code OverflowError} on overflow.
 * <li>{@link #executeExact(Frame, Object, PythonBuiltinClassType)} raises the supplied exception
 * type on overflow.
 * </ul>
 */
@GenerateUncached
public abstract class PyNumberAsSizeNode extends PNodeWithContext {
    public final int executeLossy(Frame frame, Object object) {
        return execute(frame, object, PNone.NO_VALUE);
    }

    public final int executeExact(Frame frame, Object object) {
        return execute(frame, object, OverflowError);
    }

    public final int executeExact(Frame frame, Object object, PythonBuiltinClassType errorClass) {
        return execute(frame, object, errorClass);
    }

    protected abstract int execute(Frame frame, Object object, Object errorClass);

    @Specialization
    static int doInt(int object, @SuppressWarnings("unused") Object errorClass) {
        return object;
    }

    @Specialization
    static int doLongExact(long object, PythonBuiltinClassType errorClass,
                    @Shared("raiseNode") @Cached PRaiseNode raiseNode) {
        int converted = (int) object;
        if (object == converted) {
            return converted;
        }
        throw raiseNode.raise(errorClass, ErrorMessages.CANNOT_FIT_P_INTO_INDEXSIZED_INT, object);
    }

    @Specialization
    static int doObjectExact(VirtualFrame frame, Object object, PythonBuiltinClassType errorClass,
                    @Shared("indexNode") @Cached PyNumberIndexNode indexNode,
                    @Shared("raiseNode") @Cached PRaiseNode raiseNode,
                    @Cached CastToJavaIntExactNode cast) {
        Object index = indexNode.execute(frame, object);
        try {
            return cast.execute(index);
        } catch (PException pe) {
            throw raiseNode.raise(errorClass, ErrorMessages.CANNOT_FIT_P_INTO_INDEXSIZED_INT, object);
        } catch (CannotCastException cannotCastException) {
            throw CompilerDirectives.shouldNotReachHere("PyNumberIndexNode didn't return a python integer");
        }
    }

    @Specialization
    static int doLongLossy(long object, @SuppressWarnings("unused") PNone errorClass) {
        int converted = (int) object;
        if (object == converted) {
            return converted;
        }
        return object > 0 ? Integer.MAX_VALUE : Integer.MIN_VALUE;
    }

    @Specialization
    static int doObjectLossy(VirtualFrame frame, Object object, @SuppressWarnings("unused") PNone errorClass,
                    @Shared("indexNode") @Cached PyNumberIndexNode indexNode,
                    @Cached CastToJavaIntLossyNode cast) {
        Object index = indexNode.execute(frame, object);
        try {
            return cast.execute(index);
        } catch (CannotCastException cannotCastException) {
            throw CompilerDirectives.shouldNotReachHere("PyNumberIndexNode didn't return a python integer");
        }
    }

    public static PyNumberAsSizeNode create() {
        return PyNumberAsSizeNodeGen.create();
    }

    public static PyNumberAsSizeNode getUncached() {
        return PyNumberAsSizeNodeGen.getUncached();
    }
}
