/*

 * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.graalvm.compiler.replacements.amd64;

import org.graalvm.compiler.api.replacements.ClassSubstitution;

import org.graalvm.compiler.api.replacements.Fold;

import org.graalvm.compiler.api.replacements.Fold.InjectedParameter;

import org.graalvm.compiler.api.replacements.MethodSubstitution;

import org.graalvm.compiler.core.common.SuppressFBWarnings;

import org.graalvm.compiler.graph.Node.ConstantNodeParameter;

import org.graalvm.compiler.replacements.StringSubstitutions;

import org.graalvm.compiler.replacements.nodes.ArrayCompareToNode;

import org.graalvm.compiler.replacements.nodes.ArrayRegionEqualsNode;

import org.graalvm.compiler.word.Word;

import jdk.internal.vm.compiler.word.Pointer;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.MetaAccessProvider;

// JaCoCo Exclude

/**

 * Substitutions for {@link java.lang.String} methods.

 */

@ClassSubstitution(String.class)

public class AMD64StringSubstitutions {

    @Fold

    static int charArrayBaseOffset(@InjectedParameter MetaAccessProvider metaAccess) {

        return metaAccess.getArrayBaseOffset(JavaKind.Char);

    }

    @Fold

    static int charArrayIndexScale(@InjectedParameter MetaAccessProvider metaAccess) {

        return metaAccess.getArrayIndexScale(JavaKind.Char);

    }

    /** Marker value for the {@link InjectedParameter} injected parameter. */

    static final MetaAccessProvider INJECTED = null;

    // Only exists in JDK <= 8

    @MethodSubstitution(isStatic = true, optional = true)

    public static int indexOf(char[] source, int sourceOffset, int sourceCount,

                    @ConstantNodeParameter char[] target, int targetOffset, int targetCount,

                    int origFromIndex) {

        int fromIndex = origFromIndex;

        if (fromIndex >= sourceCount) {

            return (targetCount == 0 ? sourceCount : -1);

        }

        if (fromIndex < 0) {

            fromIndex = 0;

        }

        if (targetCount == 0) {

            // The empty string is in every string.

            return fromIndex;

        }

        int totalOffset = sourceOffset + fromIndex;

        if (sourceCount - fromIndex < targetCount) {

            // The empty string contains nothing except the empty string.

            return -1;

        }

        if (targetCount == 1) {

            return AMD64ArrayIndexOf.indexOf1Char(source, sourceCount, totalOffset, target[targetOffset]);

        } else {

            int haystackLength = sourceCount - (targetCount - 2);

            while (totalOffset < haystackLength) {

                int indexOfResult = AMD64ArrayIndexOf.indexOfTwoConsecutiveChars(source, haystackLength, totalOffset, target[targetOffset], target[targetOffset + 1]);

                if (indexOfResult < 0) {

                    return -1;

                }

                totalOffset = indexOfResult;

                if (targetCount == 2) {

                    return totalOffset;

                } else {

                    Pointer cmpSourcePointer = Word.objectToTrackedPointer(source).add(charArrayBaseOffset(INJECTED)).add(totalOffset * charArrayIndexScale(INJECTED));

                    Pointer targetPointer = Word.objectToTrackedPointer(target).add(charArrayBaseOffset(INJECTED)).add(targetOffset * charArrayIndexScale(INJECTED));

                    if (ArrayRegionEqualsNode.regionEquals(cmpSourcePointer, targetPointer, targetCount, JavaKind.Char)) {

                        return totalOffset;

                    }

                }

                totalOffset++;

            }

            return -1;

        }

    }

    // Only exists in JDK <= 8

    @MethodSubstitution(isStatic = false, optional = true)

    public static int indexOf(String source, int ch, int origFromIndex) {

        int fromIndex = origFromIndex;

        final int sourceCount = source.length();

        if (fromIndex >= sourceCount) {

            // Note: fromIndex might be near -1>>>1.

            return -1;

        }

        if (fromIndex < 0) {

            fromIndex = 0;

        }

        if (ch < Character.MIN_SUPPLEMENTARY_CODE_POINT) {

            char[] sourceArray = StringSubstitutions.getValue(source);

            return AMD64ArrayIndexOf.indexOf1Char(sourceArray, sourceCount, fromIndex, (char) ch);

        } else {

            return indexOf(source, ch, origFromIndex);

        }

    }

    @MethodSubstitution(isStatic = false)

    @SuppressFBWarnings(value = "ES_COMPARING_PARAMETER_STRING_WITH_EQ", justification = "reference equality on the receiver is what we want")

    public static int compareTo(String receiver, String anotherString) {

        if (receiver == anotherString) {

            return 0;

        }

        char[] value = StringSubstitutions.getValue(receiver);

        char[] other = StringSubstitutions.getValue(anotherString);

        return ArrayCompareToNode.compareTo(value, other, value.length << 1, other.length << 1, JavaKind.Char, JavaKind.Char);

    }

}