Import all sources from perforce.

src/nvcore/BitArray.h

@@ -0,0 +1,168 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#ifndef NV_CORE_BITARRAY_H
+#define NV_CORE_BITARRAY_H
+
+#include <nvcore/nvcore.h>
+#include <nvcore/Containers.h>
+
+namespace nv
+{
+
+/// Count the bits of @a x.
+inline uint bitsSet(uint8 x) {
+	uint count = 0;
+	for(; x != 0; x >>= 1) {
+		count += (x & 1);
+	}
+	return count;
+}
+
+
+/// Count the bits of @a x.
+inline uint bitsSet(uint32 x, int bits) {
+	uint count = 0;
+	for(; x != 0 && bits != 0; x >>= 1, bits--) {
+		count += (x & 1);
+	}
+	return count;
+}
+
+
+/// Simple bit array.
+class BitArray
+{
+public:
+
+	/// Default ctor.
+	BitArray() {}
+
+	/// Ctor with initial m_size.
+	BitArray(uint sz)
+	{
+		resize(sz);
+	}
+
+	/// Get array m_size.
+	uint size() const { return m_size; }
+
+	/// Clear array m_size.
+	void clear() { resize(0); }
+
+	/// Set array m_size.
+	void resize(uint sz)
+	{ 
+		m_size = sz;
+		m_bitArray.resize( (m_size + 7) >> 3 );
+	}
+	
+	/// Get bit.
+	bool bitAt(uint b) const
+	{
+		nvDebugCheck( b < m_size );
+		return (m_bitArray[b >> 3] & (1 << (b & 7))) != 0;
+	}
+
+	/// Set a bit.
+	void setBitAt(uint b)
+	{
+		nvDebugCheck( b < m_size );
+		m_bitArray[b >> 3] |=  (1 << (b & 7));
+	}
+
+	/// Clear a bit.
+	void clearBitAt( uint b )
+	{
+		nvDebugCheck( b < m_size );
+		m_bitArray[b >> 3] &= ~(1 << (b & 7));
+	}
+
+	/// Clear all the bits.
+	void clearAll()
+	{
+		memset(m_bitArray.unsecureBuffer(), 0, m_bitArray.size());
+	}
+
+	/// Set all the bits.
+	void setAll()
+	{
+		memset(m_bitArray.unsecureBuffer(), 0xFF, m_bitArray.size());
+	}
+
+	/// Toggle all the bits.
+	void toggleAll()
+	{
+		const uint byte_num = m_bitArray.size();
+		for(uint b = 0; b < byte_num; b++) {
+			m_bitArray[b] ^= 0xFF;
+		}
+	}
+	
+	/// Get a byte of the bit array.
+	const uint8 & byteAt(uint index) const
+	{
+		return m_bitArray[index];
+	}
+
+	/// Set the given byte of the byte array.
+	void setByteAt(uint index, uint8 b)
+	{
+		m_bitArray[index] = b;
+	}
+	
+	/// Count the number of bits set.
+	uint countSetBits() const
+	{
+		const uint num = m_bitArray.size();
+		if( num == 0 ) {
+			return 0;
+		}
+		
+		uint count = 0;				
+		for(uint i = 0; i < num - 1; i++) {
+			count += bitsSet(m_bitArray[i]);
+		}
+		count += bitsSet(m_bitArray[num-1], m_size & 0x7);
+		
+		//piDebugCheck(count + countClearBits() == m_size);
+		return count;
+	}
+
+	/// Count the number of bits clear.
+	uint countClearBits() const {
+		
+		const uint num = m_bitArray.size();
+		if( num == 0 ) {
+			return 0;
+		}
+		
+		uint count = 0;
+		for(uint i = 0; i < num - 1; i++) {
+			count += bitsSet(~m_bitArray[i]);
+		}
+		count += bitsSet(~m_bitArray[num-1], m_size & 0x7);
+		
+		//piDebugCheck(count + countSetBits() == m_size);
+		return count;
+	}
+
+	friend void swap(BitArray & a, BitArray & b)
+	{
+		swap(a.m_size, b.m_size);
+		swap(a.m_bitArray, b.m_bitArray);
+	}
+
+
+private:
+
+	/// Number of bits stored.
+	uint m_size;
+
+	/// Array of bits.
+	Array<uint8> m_bitArray;
+
+};
+
+} // nv namespace
+
+#endif // _PI_CORE_BITARRAY_H_