bitVector.hpp

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/* Copyright 1994, LongView Technologies L.L.C. $Revision: 1.9 $ */
/* Copyright (c) 2006, Sun Microsystems, Inc.
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// General bit vectors; space is allocated for maxLength bits, but only
// the portion up to length bits is used.
// SimpleBitVector: simple version that fits into a word (for speed)

# ifdef DELTA_COMPILER

  typedef void (*intDoFn)(int i);
  
  // a pseudo-class -- int(this) actually holds the bits, so there's no
  // allocation
  class SimpleBitVector : public ValueObj {
    int bits;
   public:
    SimpleBitVector(int b = 0) { bits = b; } 

    SimpleBitVector allocate(int l) {
      assert(l >= 0 && l < BitsPerWord, "need longer bit vector");
      return SimpleBitVector(addNth(bits, l));
    }

    SimpleBitVector deallocate(int l) {
      assert(l >= 0 && l < BitsPerWord, "need longer bit vector");
      return SimpleBitVector(subNth(bits, l));
    }

    bool isAllocated(int l) {
      assert(l >= 0 && l < BitsPerWord, "need longer bit vector");
      return isSet(bits, l);
    }
    bool isEmpty() { return bits == 0; }
  };

  class BitVector:  public PrintableResourceObj {
   protected:
    int maxLength;              // max # bits
    int length;                 // number of bits, not words
    int* bits;                  // array containing the bits
    
    int  indexFromNumber(int i) { return i >> LogBitsPerWord; }
    int offsetFromNumber(int i) { return lowerBits(i, LogBitsPerWord); }
    
    bool getBitInWord(int i, int o) { return isSet(bits[i], o); }
    void setBitInWord(int i, int o) {       setNth(bits[i], o); }
    void clearBitInWord(int i, int o) {   clearNth(bits[i], o); }
    
    int bitsLength(int l) { return indexFromNumber(l - 1) + 1; }
    
    int* createBitString(int l) {
      int blen = bitsLength(l);
      int* bs = NEW_RESOURCE_ARRAY( int, blen);
      set_words(bs, blen, 0);
      return bs; }
    int* copyBitString(int len) {
      assert(len >= maxLength, "can't shorten");
      int blen = bitsLength(len);
      int* bs = NEW_RESOURCE_ARRAY( int, blen);
      int blength = bitsLength(maxLength);
      copy_words(bits, bs, blength);
      if (blength < blen) set_words(bs + blength, blen - blength, 0);
      return bs; }
    
  public:
    BitVector(int l) {
      assert(l > 0, "should have some length");
      length = maxLength = l; bits = createBitString(l); }
    
  protected:
    BitVector(int l, int ml, int* bs) {
      maxLength = ml; length = l; bits = bs; }
    
  public:
    BitVector* copy(int len) {
      return new BitVector(length, len, copyBitString(len)); }
    
    bool includes(int i) {
      assert(this, "shouldn't be a null pointer");
      assert(i >= 0 && i < length, "not in range");
      bool b = getBitInWord(indexFromNumber(i), offsetFromNumber(i));
      return b; }
    void add(int i) {
      assert(this, "shouldn't be a null pointer");
      assert(i >= 0 && i < length, "not in range");
      setBitInWord(indexFromNumber(i), offsetFromNumber(i)); }
    void addFromTo(int first, int last);        // set bits [first..last]
    void remove(int i) {
      assert(this, "shouldn't be a null pointer");
      assert(i >= 0 && i < length, "not in range");
      clearBitInWord(indexFromNumber(i), offsetFromNumber(i)); }
    void removeFromTo(int first, int last);     // clear bits [first..last]

    // union/intersect return true if receiver has changed
    bool unionWith(BitVector* other);           // this |= other
    bool intersectWith(BitVector* other);       // this &= other
    bool isDisjointFrom(BitVector* other);      // (this & other) == {}

    void doForAllOnes(intDoFn f);  // call f for all 1 bits

    void setLength(int l)       { assert(l < maxLength, "too big"); length = l; }
    void clear()                { set_words(bits, bitsLength(length), 0); }
    
    void print_short();
    void print();

    friend class LongRegisterMask;
    friend int findFirstUnused(LongRegisterMask** strings, int len, int start);
  };
  
# endif

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