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For more * information on the Apache Software Foundation, please see * . */ package com.sun.org.apache.xerces.internal.impl.dtd.models; /** * This class is a very simple bitset class. The DFA content model code needs * to support a bit set, but the java BitSet class is way, way overkill. Our * bitset never needs to be expanded after creation, hash itself, etc... * * Since the vast majority of content models will never require more than 64 * bits, and since allocation of anything in Java is expensive, this class * provides a hybrid implementation that uses two ints for instances that use * 64 bits or fewer. It has a byte array reference member which will only be * used if more than 64 bits are required. * * Note that the code that uses this class will never perform operations * on sets of different sizes, so that check does not have to be made here. * * @version $Id: CMStateSet.java,v 1.3 2002/01/29 01:15:10 lehors Exp $ */ // made this class public so it can be accessed by // the XS content models from the schema package -neilg. public class CMStateSet { // ------------------------------------------------------------------- // Constructors // ------------------------------------------------------------------- public CMStateSet(int bitCount) { // Store the required bit count and insure its legal fBitCount = bitCount; if (fBitCount < 0) throw new RuntimeException("ImplementationMessages.VAL_CMSI"); // // See if we need to allocate the byte array or whether we can live // within the 64 bit high performance scheme. // if (fBitCount > 64) { fByteCount = fBitCount / 8; if (fBitCount % 8 != 0) fByteCount++; fByteArray = new byte[fByteCount]; } // Init all the bits to zero zeroBits(); } // ------------------------------------------------------------------- // Public inherited methods // ------------------------------------------------------------------- public String toString() { StringBuffer strRet = new StringBuffer(); try { strRet.append("{"); for (int index = 0; index < fBitCount; index++) { if (getBit(index)) strRet.append(" " + index); } strRet.append(" }"); } catch(RuntimeException exToCatch) { // // We know this won't happen but we have to catch it to avoid it // having to be in our 'throws' list. // } return strRet.toString(); } // ------------------------------------------------------------------- // Package final methods // ------------------------------------------------------------------- // the XS content models from the schema package -neilg. public final void intersection(CMStateSet setToAnd) { if (fBitCount < 65) { fBits1 &= setToAnd.fBits1; fBits2 &= setToAnd.fBits2; } else { for (int index = fByteCount - 1; index >= 0; index--) fByteArray[index] &= setToAnd.fByteArray[index]; } } public final boolean getBit(int bitToGet) { if (bitToGet >= fBitCount) throw new RuntimeException("ImplementationMessages.VAL_CMSI"); if (fBitCount < 65) { final int mask = (0x1 << (bitToGet % 32)); if (bitToGet < 32) return (fBits1 & mask) != 0; else return (fBits2 & mask) != 0; } else { // Create the mask and byte values final byte mask = (byte)(0x1 << (bitToGet % 8)); final int ofs = bitToGet >> 3; // And access the right bit and byte return ((fByteArray[ofs] & mask) != 0); } } public final boolean isEmpty() { if (fBitCount < 65) { return ((fBits1 == 0) && (fBits2 == 0)); } else { for (int index = fByteCount - 1; index >= 0; index--) { if (fByteArray[index] != 0) return false; } } return true; } final boolean isSameSet(CMStateSet setToCompare) { if (fBitCount != setToCompare.fBitCount) return false; if (fBitCount < 65) { return ((fBits1 == setToCompare.fBits1) && (fBits2 == setToCompare.fBits2)); } for (int index = fByteCount - 1; index >= 0; index--) { if (fByteArray[index] != setToCompare.fByteArray[index]) return false; } return true; } // the XS content models from the schema package -neilg. public final void union(CMStateSet setToOr) { if (fBitCount < 65) { fBits1 |= setToOr.fBits1; fBits2 |= setToOr.fBits2; } else { for (int index = fByteCount - 1; index >= 0; index--) fByteArray[index] |= setToOr.fByteArray[index]; } } public final void setBit(int bitToSet) { if (bitToSet >= fBitCount) throw new RuntimeException("ImplementationMessages.VAL_CMSI"); if (fBitCount < 65) { final int mask = (0x1 << (bitToSet % 32)); if (bitToSet < 32) { fBits1 &= ~mask; fBits1 |= mask; } else { fBits2 &= ~mask; fBits2 |= mask; } } else { // Create the mask and byte values final byte mask = (byte)(0x1 << (bitToSet % 8)); final int ofs = bitToSet >> 3; // And access the right bit and byte fByteArray[ofs] &= ~mask; fByteArray[ofs] |= mask; } } // the XS content models from the schema package -neilg. public final void setTo(CMStateSet srcSet) { // They have to be the same size if (fBitCount != srcSet.fBitCount) throw new RuntimeException("ImplementationMessages.VAL_CMSI"); if (fBitCount < 65) { fBits1 = srcSet.fBits1; fBits2 = srcSet.fBits2; } else { for (int index = fByteCount - 1; index >= 0; index--) fByteArray[index] = srcSet.fByteArray[index]; } } // had to make this method public so it could be accessed from // schema package - neilg. public final void zeroBits() { if (fBitCount < 65) { fBits1 = 0; fBits2 = 0; } else { for (int index = fByteCount - 1; index >= 0; index--) fByteArray[index] = 0; } } // ------------------------------------------------------------------- // Private data members // // fBitCount // The count of bits that the outside world wants to support, // so its the max bit index plus one. // // fByteCount // If the bit count is > 64, then we use the fByteArray member to // store the bits, and this indicates its size in bytes. Otherwise // its value is meaningless. // // fBits1 // fBits2 // When the bit count is < 64 (very common), these hold the bits. // Otherwise, the fByteArray member holds htem. // ------------------------------------------------------------------- int fBitCount; int fByteCount; int fBits1; int fBits2; byte[] fByteArray; /* Optimization(Jan, 2001) */ public boolean equals(Object o) { if (!(o instanceof CMStateSet)) return false; return isSameSet((CMStateSet)o); } public int hashCode() { if (fBitCount < 65) { return fBits1+ fBits2 * 31; } else { int hash = 0; for (int index = fByteCount - 1; index >= 0; index--) hash = fByteArray[index] + hash * 31; return hash; } } /* Optimization(Jan, 2001) */ };