CyrusBuilt.MonoPi.BitSet.Get C# (CSharp) Method

BitSet Class Documentation 显示文件 Open project: cyrusbuilt/MonoPi

Get() public method

Returns a new bit set composed of bits from this bit set from the specified from index (inclusive) to the to index (exclusive).

/// is less than zero - or - /// is less than zero - or - /// is greater than . ///

public Get ( Int32 from, Int32 to ) : BitSet
from	System.Int32	/// The index of the first bit to include. ///
to	System.Int32	/// The index after the last bit to include. ///
return	BitSet

		public BitSet Get(Int32 from, Int32 to) {
			CheckRange(from, to);
			this.CheckInvariants();

			// If no set bits in range, the return empty BitSet.
			Int32 len = this.Length;
			if ((len <= from) || (from == to)) {
				return new BitSet(0);
			}

			// Optimize.
			if (to > len) {
				to = len;
			}

			BitSet bs = new BitSet(to - from);
			Int32 targetWords = WordIndex(to - from - 1) + 1;
			Int32 sourceIndex = WordIndex(from);
			Boolean aligned = ((from & BIT_INDEX_MASK) == 0);

			// Process all words but the last one.
			for (Int32 i = 0; i < targetWords - 1; i++, sourceIndex++) {
				bs._bits[i] = aligned ? this._bits[sourceIndex] :
					(this._bits[sourceIndex] >> from) |
					(this._bits[sourceIndex + 1] << -from);
			}

			// Process the last word.
			long lastWordMask = LONG_MASK >> -to;
			bs._bits[targetWords - 1] = ((to - 1) & BIT_INDEX_MASK) < (from & BIT_INDEX_MASK) ?
				((this._bits[sourceIndex] >> from) |
			(this._bits[sourceIndex + 1] & lastWordMask) << -from) :
				((this._bits[sourceIndex] & lastWordMask) >> from);

			bs._wordsInUse = targetWords;
			bs.RecalculateWordsInUse();
			bs.CheckInvariants();
			return bs;
		}