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 * The Universal Permissive License (UPL), Version 1.0
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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
 * is contributed by such licensors),
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 * 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
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package com.oracle.graal.python.lib;

import static com.oracle.graal.python.builtins.PythonBuiltinClassType.TypeError;
import static com.oracle.graal.python.builtins.PythonBuiltinClassType.ValueError;

import com.oracle.graal.python.builtins.objects.buffer.BufferAcquireGenerateUncachedNode;
import com.oracle.graal.python.builtins.objects.buffer.PythonBufferAccessLibrary;
import com.oracle.graal.python.builtins.objects.floats.FloatUtils;
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.CastToJavaStringNode;
import com.oracle.graal.python.runtime.exception.PException;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
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;
import com.oracle.truffle.api.strings.TruffleString;

/**
 * Equivalent of CPython's {@code PyFloat_FromString}. Converts a string to a python float (Java
 * {@code double}). Raises {@code ValueError} when the conversion fails.
 */
@GenerateUncached
public abstract class PyFloatFromString extends PNodeWithContext {
    public abstract double execute(Frame frame, Object obj);

    public abstract double execute(Frame frame, TruffleString obj);

    @Specialization
    static double doString(VirtualFrame frame, TruffleString object,
                    @Cached TruffleString.ToJavaStringNode toJavaStringNode,
                    @Shared("repr") @Cached PyObjectReprAsTruffleStringNode reprNode,
                    @Shared("raise") @Cached PRaiseNode raiseNode) {
        return convertStringToDouble(frame, toJavaStringNode.execute(object), object, reprNode, raiseNode);
    }

    @Specialization
    double doGeneric(VirtualFrame frame, Object object,
                    @Cached(parameters = "3") BufferAcquireGenerateUncachedNode acquireNode,
                    @Cached CastToJavaStringNode cast,
                    @Shared("repr") @Cached PyObjectReprAsTruffleStringNode reprNode,
                    @Shared("raise") @Cached PRaiseNode raiseNode) {
        String string = null;
        try {
            string = cast.execute(object);
        } catch (CannotCastException e) {
            Object buffer = null;
            try {
                buffer = acquireNode.acquireReadonly(frame, object);
            } catch (PException e1) {
                // fallthrough
            }
            if (buffer != null) {
                try {
                    PythonBufferAccessLibrary accessLib = acquireNode.getAccessLib();
                    byte[] bytes = accessLib.getInternalOrCopiedByteArray(buffer);
                    int len = accessLib.getBufferLength(buffer);
                    string = newString(bytes, 0, len);
                } finally {
                    acquireNode.release(frame, buffer);
                }
            }
        }
        if (string != null) {
            return convertStringToDouble(frame, string, object, reprNode, raiseNode);
        }
        throw raiseNode.raise(TypeError, ErrorMessages.ARG_MUST_BE_STRING_OR_NUMBER, "float()", object);
    }

    @TruffleBoundary(allowInlining = true)
    private static String newString(byte[] bytes, int offset, int length) {
        return new String(bytes, offset, length);
    }

    private static double convertStringToDouble(VirtualFrame frame, String src, Object origObj, PyObjectReprAsTruffleStringNode reprNode, PRaiseNode raiseNode) {
        String str = FloatUtils.removeUnicodeAndUnderscores(src);
        // Adapted from CPython's float_from_string_inner
        if (str != null) {
            int len = str.length();
            int offset = FloatUtils.skipAsciiWhitespace(str, 0, len);
            FloatUtils.StringToDoubleResult res = FloatUtils.stringToDouble(str, offset, len);
            if (res != null) {
                int end = FloatUtils.skipAsciiWhitespace(str, res.position, len);
                if (end == len) {
                    return res.value;
                }
            }
        }
        TruffleString repr;
        try {
            repr = reprNode.execute(frame, origObj);
        } catch (PException e) {
            // Failed to format the message. Mirrors CPython behavior when the repr fails
            throw raiseNode.raise(ValueError);
        }
        throw raiseNode.raise(ValueError, ErrorMessages.COULD_NOT_CONVERT_STRING_TO_FLOAT, repr);
    }

}
