java.util.BitSet.trimToSize()方法的使用及代码示例

x33g5p2x  于2022-01-16 转载在 其他  
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本文整理了Java中java.util.BitSet.trimToSize()方法的一些代码示例，展示了BitSet.trimToSize()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。BitSet.trimToSize()方法的具体详情如下：
包路径：java.util.BitSet
类名称：BitSet
方法名：trimToSize

BitSet.trimToSize介绍

[英]Attempts to reduce internal storage used for the bits in this bit set. Calling this method may, but is not required to, affect the value returned by a subsequent call to the #size() method.
[中]尝试减少用于此位集中位的内部存储。调用此方法可能会（但不是必需的）影响后续调用#size（）方法返回的值。

代码示例

代码示例来源：origin: junkdog/artemis-odb

  1. /**
  2.  * This hash is different than the one described in Sun's documentation. The
  3.  * described hash uses 64 bit integers and that's not practical in
  4.  * JavaScript.
  5.  */
  6. @Override
  7. public int hashCode() {
  8.   // FNV constants
  9.   final int fnvOffset = 0x811c9dc5;
  10.   final int fnvPrime = 0x1000193;
  11.   // initialize
  12.   final int last = trimToSize(array);
  13.   int hash = fnvOffset ^ last;
  14.   // loop over the data
  15.   for (int i = 0; i <= last; i++) {
  16.     int value = getWord(array, i);
  17.     // hash one byte at a time using FNV1
  18.     hash = (hash * fnvPrime) ^ (value & 0xff);
  19.     hash = (hash * fnvPrime) ^ ((value >>> 8) & 0xff);
  20.     hash = (hash * fnvPrime) ^ ((value >>> 16) & 0xff);
  21.     hash = (hash * fnvPrime) ^ (value >>> 24);
  22.   }
  23.   return hash;
  24. }

代码示例来源：origin: jtulach/bck2brwsr

  1. /**
  2.  * Cloning this {@code BitSet} produces a new {@code BitSet}
  3.  * that is equal to it.
  4.  * The clone of the bit set is another bit set that has exactly the
  5.  * same bits set to {@code true} as this bit set.
  6.  *
  7.  * @return a clone of this bit set
  8.  * @see    #size()
  9.  */
  10. public Object clone() {
  11.   if (! sizeIsSticky)
  12.     trimToSize();
  13.   try {
  14.     BitSet result = (BitSet) super.clone();
  15.     result.words = words.clone();
  16.     result.checkInvariants();
  17.     return result;
  18.   } catch (CloneNotSupportedException e) {
  19.     throw new InternalError();
  20.   }
  21. }

代码示例来源：origin: org.apidesign.bck2brwsr/emul

  1. /**
  2.  * Cloning this {@code BitSet} produces a new {@code BitSet}
  3.  * that is equal to it.
  4.  * The clone of the bit set is another bit set that has exactly the
  5.  * same bits set to {@code true} as this bit set.
  6.  *
  7.  * @return a clone of this bit set
  8.  * @see    #size()
  9.  */
  10. public Object clone() {
  11.   if (! sizeIsSticky)
  12.     trimToSize();
  13.   try {
  14.     BitSet result = (BitSet) super.clone();
  15.     result.words = words.clone();
  16.     result.checkInvariants();
  17.     return result;
  18.   } catch (CloneNotSupportedException e) {
  19.     throw new InternalError();
  20.   }
  21. }

代码示例来源：origin: junkdog/artemis-odb

  1. public int length() {
  2.   int last = trimToSize(array);
  3.   if (last == -1) {
  4.     return 0;
  5.   }
  6.   // compute the position of the leftmost bit's index
  7.   int offsets[] = { 16, 8, 4, 2, 1 };
  8.   int bitMasks[] = { 0xffff0000, 0xff00, 0xf0, 0xc, 0x2 };
  9.   int position = bitIndex(last) + 1;
  10.   int word = getWord(array, last);
  11.   for (int i = 0; i < offsets.length; i++) {
  12.     if ((word & bitMasks[i]) != 0) {
  13.       word >>>= offsets[i];
  14.       position += offsets[i];
  15.     }
  16.   }
  17.   return position;
  18. }

代码示例来源：origin: junkdog/artemis-odb

  1. @Override
  2. public boolean equals(Object obj) {
  3.   if (this != obj) {
  4.     if (!ClassReflection.isInstance(BitSet.class, obj)) {
  5.       return false;
  6.     }
  7.     BitSet other = (BitSet) obj;
  8.     int last = trimToSize(array);
  9.     if (last != trimToSize(other.array)) {
  10.       return false;
  11.     }
  12.     int index = 0;
  13.     while ((index = nextSetWord(array, index)) != -1) {
  14.       if (getWord(array, index) != getWord(other.array, index)) {
  15.         return false;
  16.       }
  17.       index++;
  18.     }
  19.   }
  20.   return true;
  21. }

代码示例来源：origin: jtulach/bck2brwsr

  1. /**
  2.  * Save the state of the {@code BitSet} instance to a stream (i.e.,
  3.  * serialize it).
  4.  */
  5. private void writeObject(ObjectOutputStream s)
  6.   throws IOException {
  7.   checkInvariants();
  8.   if (! sizeIsSticky)
  9.     trimToSize();
  10.   ObjectOutputStream.PutField fields = s.putFields();
  11.   fields.put("bits", words);
  12.   s.writeFields();
  13. }

代码示例来源：origin: org.apidesign.bck2brwsr/emul

  1. /**
  2.  * Save the state of the {@code BitSet} instance to a stream (i.e.,
  3.  * serialize it).
  4.  */
  5. private void writeObject(ObjectOutputStream s)
  6.   throws IOException {
  7.   checkInvariants();
  8.   if (! sizeIsSticky)
  9.     trimToSize();
  10.   ObjectOutputStream.PutField fields = s.putFields();
  11.   fields.put("bits", words);
  12.   s.writeFields();
  13. }

代码示例来源：origin: junkdog/artemis-odb

  1. public boolean intersects(BitSet set) {
  2.   int last = trimToSize(array);
  3.   if (this == set) {
  4.     // if it has any bits then it intersects itself
  5.     return last != -1;
  6.   }
  7.   int length = set.array.length();
  8.   int index = 0;
  9.   while ((index = nextSetWord(array, index)) != -1) {
  10.     if ((array.get(index) & getWord(set.array, index)) != 0) {
  11.       return true;
  12.     }
  13.     if (++index >= length) {
  14.       // nothing further can intersect
  15.       break;
  16.     }
  17.   }
  18.   return false;
  19. }

代码示例来源：origin: junkdog/artemis-odb

  1. public void andNot(BitSet set) {
  2.   // a & !a is false
  3.   if (this == set) {
  4.     // all falses result in an empty BitSet
  5.     clear();
  6.     return;
  7.   }
  8.   // trim the second set to avoid extra work
  9.   trimToSize(array);
  10.   int length = array.length();
  11.   // truth table
  12.   //
  13.   // case | a | b | !b | a & !b | change?
  14.   // 1 | false | false | true | false | a is already false
  15.   // 2 | false | true | false | false | a is already false
  16.   // 3 | true | false | true | true | a is already true
  17.   // 4 | true | true | false | false | set a to false
  18.   //
  19.   // we only need to change something in case 4
  20.   // whenever b is true, a should be false, so iterate over set b
  21.   int index = 0;
  22.   while ((index = nextSetWord(set.array, index)) != -1) {
  23.     setWord(array, index, getWord(array, index) & ~set.array.get(index));
  24.     if (++index >= length) {
  25.       // nothing further will affect anything
  26.       break;
  27.     }
  28.   }
  29. }

代码示例来源：origin: junkdog/artemis-odb

  1. public int nextSetBit(int fromIndex) {
  2.   checkIndex(fromIndex);
  3.   int index = wordIndex(fromIndex);
  4.   // check the current word
  5.   int word = getWord(array, index);
  6.   if (word != 0) {
  7.     for (int i = bitOffset(fromIndex); i < 32; i++) {
  8.       if ((word & (1 << i)) != 0) {
  9.         return (bitIndex(index)) + i;
  10.       }
  11.     }
  12.   }
  13.   index++;
  14.   // find the next set word
  15.   trimToSize(array);
  16.   index = nextSetWord(array, index);
  17.   if (index == -1) {
  18.     return -1;
  19.   }
  20.   // return the next set bit
  21.   return (bitIndex(index))
  22.       + Integer.numberOfTrailingZeros(array.get(index));
  23. };

代码示例来源：origin: junkdog/artemis-odb

  1. public void and(BitSet set) {
  2.   // a & a is just a
  3.   if (this == set) {
  4.     return;
  5.   }
  6.   // trim the second set to avoid extra work
  7.   trimToSize(set.array);
  8.   // check if the length is longer than otherLength
  9.   int otherLength = set.array.length();
  10.   if (array.length() > otherLength) {
  11.     // shrink the array, effectively ANDing those bits to false
  12.     setLengthWords(array, otherLength);
  13.   }
  14.   // truth table
  15.   //
  16.   // case | a | b | a & b | change?
  17.   // 1 | false | false | false | a is already false
  18.   // 2 | false | true | false | a is already false
  19.   // 3 | true | false | false | set a to false
  20.   // 4 | true | true | true | a is already true
  21.   //
  22.   // we only need to change something in case 3, so iterate over set a
  23.   int index = 0;
  24.   while ((index = nextSetWord(array, index)) != -1) {
  25.     setWord(array, index, array.get(index) & getWord(set.array, index));
  26.     index++;
  27.   }
  28. }

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