src/base/bitarray.h

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#ifndef MOZC_BASE_BITARRAY_H_
#define MOZC_BASE_BITARRAY_H_

#include <string.h>   // memset
#include "base/port.h"

namespace mozc {

class BitArray {
 public:
  // Specify the size of bit vector
  explicit BitArray(uint32 size)
      : array_(new uint32[1 + (size >> 5)]), size_(size) {
    memset(reinterpret_cast<char *>(array_), 0, 4 * (1 + (size >> 5)));
  }

  ~BitArray() {
    delete [] array_;
    array_ = NULL;
  }

  // get true/false of |index|
  inline bool get(uint32 index) const {
    return static_cast<bool>(
        (array_[(index >> 5)] >> (index & 0x0000001F)) & 0x00000001);
  }

  // set |index| as true
  inline void set(uint32 index) {
    array_[(index >> 5)] |= 0x00000001 << (index & 0x0000001F);
  }

  // set |index| as false
  inline void clear(uint32 index) {
    array_[(index >> 5)] &= ~(0x00000001 << (index & 0x0000001F));
  }

  // return the body of bit vector
  const char *array() const {
    return reinterpret_cast<const char *>(array_);
  }

  // return the required buffer size for saving the bit vector
  size_t array_size() const {
    return 4 * (1 + (size_ >> 5));
  }

  // return number of bit(s)
  size_t size() const {
    return size_;
  }

  // immutable acessor
  static bool GetValue(const char *array, uint32 index) {
    const uint32 *uarray = reinterpret_cast<const uint32 *>(array);
    return static_cast<bool>(
        (uarray[(index >> 5)] >> (index & 0x0000001F)) & 0x00000001);
  }

 private:
  uint32 *array_;
  size_t size_;
};
}  // namespace mozc
#endif  // MOZC_BASE_BITARRAY_H_