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package org.netbeans.lib.profiler.heap;

/**
 *
 * @author Tomas Hurka
 */
class StackFrameSegment extends TagBounds {
    //~ Instance fields ----------------------------------------------------------------------------------------------------------

    HprofHeap hprofHeap;
    final int methodIDOffset;
    final int stackFrameIDOffset;
    final int lengthOffset;
    final int sourceIDOffset;
    final int methodSignatureIDOffset;
    final int timeOffset;
    final int classSerialNumberOffset;
    final int lineNumberOffset;

    //~ Constructors -------------------------------------------------------------------------------------------------------------

    StackFrameSegment(HprofHeap heap, long start, long end) {
        super(HprofHeap.STACK_TRACE, start, end);

        int idSize = heap.dumpBuffer.getIDSize();
        hprofHeap = heap;
        timeOffset = 1;
        lengthOffset = timeOffset + 4;
        stackFrameIDOffset = lengthOffset + 4;
        methodIDOffset = stackFrameIDOffset + idSize;
        methodSignatureIDOffset = methodIDOffset + idSize;
        sourceIDOffset = methodSignatureIDOffset + idSize;
        classSerialNumberOffset = sourceIDOffset + idSize;
        lineNumberOffset = classSerialNumberOffset + 4;
    }

    //~ Methods ------------------------------------------------------------------------------------------------------------------

    StackFrame getStackFrameByID(long stackFrameID) {
        long[] offset = new long[] { startOffset };

        while (offset[0] < endOffset) {
            long start = offset[0];
            long frameID = readStackFrameTag(offset);

            if (frameID == stackFrameID) {
                return new StackFrame(this, start);
            }
        }
        return null;
    }

    private HprofByteBuffer getDumpBuffer() {
        return  hprofHeap.dumpBuffer;
    }

    private long readStackFrameTag(long[] offset) {
        long start = offset[0];

        if (hprofHeap.readTag(offset) != HprofHeap.STACK_FRAME) {
            return 0;
        }

        return getDumpBuffer().getID(start + stackFrameIDOffset);
    }
}
