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 * conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
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 * endorse or promote products derived from this software without specific prior written
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package com.oracle.truffle.llvm.parser.metadata;

import com.oracle.truffle.llvm.parser.listeners.Metadata;
import com.oracle.truffle.llvm.parser.model.symbols.constants.integer.IntegerConstant;
import com.oracle.truffle.llvm.parser.scanner.RecordBuffer;
import com.oracle.truffle.llvm.runtime.types.PrimitiveType;

public final class MDSubrange implements MDBaseNode {

    private final long lowerBound;

    private MDBaseNode count;

    private MDSubrange(long lowerBound) {
        this.lowerBound = lowerBound;
        this.count = MDVoidNode.INSTANCE;
    }

    @Override
    public void accept(MetadataVisitor visitor) {
        visitor.visit(this);
    }

    public long getLowerBound() {
        return lowerBound;
    }

    public MDBaseNode getCount() {
        return count;
    }

    @Override
    public void replace(MDBaseNode oldValue, MDBaseNode newValue) {
        if (count == oldValue) {
            count = newValue;
        }
    }

    // private static final int ARGINDEX_VERSION = 0;
    private static final int VERSION_SHIFT = 1;
    private static final long VERSION_MASK = 0b1;
    // private static final int ARGINDEX_COUNT = 1;
    // private static final int ARGINDEX_STARTFROM = 2;

    public static MDSubrange createNewFormat(RecordBuffer buffer, MetadataValueList md) {
        long version = (buffer.read() >> VERSION_SHIFT) & VERSION_MASK;
        long count = buffer.read();
        long startFrom = ParseUtil.unrotateSign(buffer.read());
        MDSubrange subrange = new MDSubrange(startFrom);
        if (version == 1) {
            // in LLVM 7+ the "count" argument is a metadata node index
            subrange.count = md.getNullable(count, subrange);

        } else {
            // prior to LLVM 7, the "count argument is a primitive value
            subrange.count = MDValue.create(new IntegerConstant(PrimitiveType.I64, count));
        }

        return subrange;
    }

    private static final int ARGINDEX_32_LOWERBOUND = 1;
    private static final int ARGINDEX_32_UPPERBOUND = 2;

    public static MDSubrange createOldFormat(long[] args, Metadata md) {
        final long lowerBound = ParseUtil.asLong(args, ARGINDEX_32_LOWERBOUND, md);
        final long upperBound = ParseUtil.asLong(args, ARGINDEX_32_UPPERBOUND, md);
        final long size = upperBound - lowerBound + 1;
        final MDSubrange subrange = new MDSubrange(lowerBound);
        subrange.count = MDValue.create(new IntegerConstant(PrimitiveType.I64, size));
        return subrange;
    }
}