llvm-6502/include/llvm/ADT/BitVector.h
2007-02-15 21:38:15 +00:00

339 lines
8.2 KiB
C++

//===- llvm/ADT/BitVector.h - Bit vectors -----------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Evan Cheng and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the BitVector class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_BITVECTOR_H
#define LLVM_ADT_BITVECTOR_H
#include "llvm/Support/MathExtras.h"
namespace llvm {
class BitVector {
typedef unsigned long BitWord;
enum { BITS_PER_WORD = sizeof(BitWord) * 8 };
BitWord *Bits; // Actual bits.
unsigned Size; // Size of bitvector in bits.
unsigned Capacity; // Size of allocated memory in BitWord.
public:
// Encapsulation of a single bit.
class reference {
friend class BitVector;
BitWord *WordRef;
unsigned BitPos;
reference(); // Undefined
public:
reference(BitVector &b, unsigned Idx) {
WordRef = &b.Bits[Idx / BITS_PER_WORD];
BitPos = Idx % BITS_PER_WORD;
}
~reference() {}
reference& operator=(bool t) {
if (t)
*WordRef |= 1L << BitPos;
else
*WordRef &= ~(1L << BitPos);
return *this;
}
operator bool() const {
return (*WordRef) & (1L << BitPos);
}
};
/// BitVector default ctor - Creates an empty bitvector.
BitVector() : Size(0), Capacity(0) {
Bits = NULL;
}
/// BitVector ctor - Creates a bitvector of specified number of bits. All
/// bits are initialized to the specified value.
explicit BitVector(unsigned s, bool t = false) : Size(s) {
Capacity = NumBitWords(s);
Bits = new BitWord[Capacity];
init_words(Bits, Capacity, t);
if (t)
clear_unused_bits();
}
/// BitVector copy ctor.
BitVector(const BitVector &RHS) : Size(RHS.size()) {
if (Size == 0) {
Bits = NULL;
Capacity = 0;
return;
}
Capacity = NumBitWords(RHS.size());
Bits = new BitWord[Capacity];
std::copy(RHS.Bits, &RHS.Bits[Capacity], Bits);
}
/// size - Returns the number of bits in this bitvector.
unsigned size() const { return Size; }
/// count - Returns the number of bits which are set.
unsigned count() const {
unsigned NumBits = 0;
for (unsigned i = 0; i < NumBitWords(size()); ++i)
if (sizeof(BitWord) == 4)
NumBits += CountPopulation_32(Bits[i]);
else if (sizeof(BitWord) == 8)
NumBits += CountPopulation_64(Bits[i]);
else
assert(0 && "Unsupported!");
return NumBits;
}
/// any - Returns true if any bit is set.
bool any() const {
for (unsigned i = 0; i < NumBitWords(size()); ++i)
if (Bits[i] != 0)
return true;
return false;
}
/// none - Returns true if none of the bits are set.
bool none() const {
return !any();
}
/// find_first - Returns the index of the first set bit, -1 if none
/// of the bits are set.
int find_first() const {
for (unsigned i = 0; i < NumBitWords(size()); ++i)
if (Bits[i] != 0)
return i * BITS_PER_WORD + CountTrailingZeros_32(Bits[i]);
return -1;
}
/// find_next - Returns the index of the next set bit following the
/// "Prev" bit. Returns -1 if the next set bit is not found.
int find_next(unsigned Prev) const {
++Prev;
if (Prev >= Size)
return -1;
unsigned WordPos = Prev / BITS_PER_WORD;
unsigned BitPos = Prev % BITS_PER_WORD;
BitWord Copy = Bits[WordPos];
// Mask off previous bits.
Copy &= ~0 << BitPos;
if (Copy != 0)
return WordPos * BITS_PER_WORD + CountTrailingZeros_32(Copy);
// Check subsequent words.
for (unsigned i = WordPos+1; i < NumBitWords(size()); ++i)
if (Bits[i] != 0)
return i * BITS_PER_WORD + CountTrailingZeros_32(Bits[i]);
return -1;
}
/// clear - Clear all bits.
void clear() {
Size = 0;
}
/// resize - Grow or shrink the bitvector.
void resize(unsigned N, bool t = false) {
if (N > Capacity * BITS_PER_WORD) {
unsigned OldCapacity = Capacity;
grow(N);
init_words(&Bits[OldCapacity], (Capacity-OldCapacity), t);
}
Size = N;
clear_unused_bits();
}
void reserve(unsigned N) {
if (N > Capacity * BITS_PER_WORD)
grow(N);
}
// Set, reset, flip
BitVector &set() {
init_words(Bits, Capacity, true);
clear_unused_bits();
return *this;
}
BitVector &set(unsigned Idx) {
Bits[Idx / BITS_PER_WORD] |= 1L << (Idx % BITS_PER_WORD);
return *this;
}
BitVector &reset() {
init_words(Bits, Capacity, false);
return *this;
}
BitVector &reset(unsigned Idx) {
Bits[Idx / BITS_PER_WORD] &= ~(1L << (Idx % BITS_PER_WORD));
return *this;
}
BitVector &flip() {
for (unsigned i = 0; i < NumBitWords(size()); ++i)
Bits[i] = ~Bits[i];
clear_unused_bits();
return *this;
}
BitVector &flip(unsigned Idx) {
Bits[Idx / BITS_PER_WORD] ^= 1L << (Idx % BITS_PER_WORD);
return *this;
}
// No argument flip.
BitVector operator~() const {
return BitVector(*this).flip();
}
// Indexing.
reference operator[](unsigned Idx) {
return reference(*this, Idx);
}
bool operator[](unsigned Idx) const {
BitWord Mask = 1L << (Idx % BITS_PER_WORD);
return (Bits[Idx / BITS_PER_WORD] & Mask) != 0;
}
bool test(unsigned Idx) const {
return (*this)[Idx];
}
// Comparison operators.
bool operator==(const BitVector &RHS) const {
if (Size != RHS.Size)
return false;
for (unsigned i = 0; i < NumBitWords(size()); ++i)
if (Bits[i] != RHS.Bits[i])
return false;
return true;
}
bool operator!=(const BitVector &RHS) const {
return !(*this == RHS);
}
// Intersection, union, disjoint union.
BitVector operator&=(const BitVector &RHS) {
assert(Size == RHS.Size && "Illegal operation!");
for (unsigned i = 0; i < NumBitWords(size()); ++i)
Bits[i] &= RHS.Bits[i];
return *this;
}
BitVector operator|=(const BitVector &RHS) {
assert(Size == RHS.Size && "Illegal operation!");
for (unsigned i = 0; i < NumBitWords(size()); ++i)
Bits[i] |= RHS.Bits[i];
return *this;
}
BitVector operator^=(const BitVector &RHS) {
assert(Size == RHS.Size && "Illegal operation!");
for (unsigned i = 0; i < NumBitWords(size()); ++i)
Bits[i] ^= RHS.Bits[i];
return *this;
}
// Assignment operator.
const BitVector &operator=(const BitVector &RHS) {
if (this == &RHS) return *this;
Size = RHS.size();
unsigned RHSWords = NumBitWords(Size);
if (Size <= Capacity * BITS_PER_WORD) {
std::copy(RHS.Bits, &RHS.Bits[RHSWords], Bits);
clear_unused_bits();
return *this;
}
// Grow the bitvector to have enough elements.
Capacity = NumBitWords(Size);
BitWord *NewBits = new BitWord[Capacity];
std::copy(RHS.Bits, &RHS.Bits[RHSWords], NewBits);
// Destroy the old bits.
delete[] Bits;
Bits = NewBits;
return *this;
}
private:
unsigned NumBitWords(unsigned S) const {
return (S + BITS_PER_WORD-1) / BITS_PER_WORD;
}
// Clear the unused top bits in the high word.
void clear_unused_bits() {
unsigned ExtraBits = Size % BITS_PER_WORD;
if (ExtraBits) {
unsigned index = Size / BITS_PER_WORD;
Bits[index] &= ~(~0L << ExtraBits);
}
}
void grow(unsigned NewSize) {
unsigned OldCapacity = Capacity;
Capacity = NumBitWords(NewSize);
BitWord *NewBits = new BitWord[Capacity];
// Copy the old bits over.
if (OldCapacity != 0)
std::copy(Bits, &Bits[OldCapacity], NewBits);
// Destroy the old bits.
delete[] Bits;
Bits = NewBits;
}
void init_words(BitWord *B, unsigned NumWords, bool t) {
memset(B, 0 - (int)t, NumWords*sizeof(BitWord));
}
};
inline BitVector operator&(const BitVector &LHS, const BitVector &RHS) {
BitVector Result(LHS);
Result &= RHS;
return Result;
}
inline BitVector operator|(const BitVector &LHS, const BitVector &RHS) {
BitVector Result(LHS);
Result |= RHS;
return Result;
}
inline BitVector operator^(const BitVector &LHS, const BitVector &RHS) {
BitVector Result(LHS);
Result ^= RHS;
return Result;
}
} // End llvm namespace
#endif