thin-provisioning-tools/persistent-data/data-structures/bitset.cc

255 lines
5.3 KiB
C++

#include "persistent-data/data-structures/array.h"
#include "persistent-data/data-structures/bitset.h"
#include "persistent-data/math_utils.h"
using namespace boost;
using namespace persistent_data;
using namespace persistent_data::bitset_detail;
using namespace std;
//----------------------------------------------------------------
namespace {
struct bitset_traits {
typedef base::le64 disk_type;
typedef uint64_t value_type;
typedef no_op_ref_counter<uint64_t> ref_counter;
static void unpack(disk_type const &disk, value_type &value) {
value = base::to_cpu<uint64_t>(disk);
}
static void pack(value_type const &value, disk_type &disk) {
disk = base::to_disk<base::le64>(value);
}
};
}
namespace persistent_data {
namespace bitset_detail {
class bitset_impl {
public:
typedef boost::shared_ptr<bitset_impl> ptr;
typedef typename persistent_data::transaction_manager::ptr tm_ptr;
bitset_impl(tm_ptr tm)
: nr_bits_(0),
array_(tm, rc_) {
}
bitset_impl(tm_ptr tm, block_address root, unsigned nr_bits)
: nr_bits_(nr_bits),
array_(tm, rc_, root, nr_bits) {
}
block_address get_root() const {
return array_.get_root();
}
void grow(unsigned new_nr_bits, bool default_value) {
pad_last_block(default_value);
resize_array(new_nr_bits, default_value);
nr_bits_ = new_nr_bits;
}
void destroy() {
throw runtime_error("bitset.destroy() not implemented");
}
// May trigger a flush, so cannot be const
bool get(unsigned n) {
check_bounds(n);
return get_bit(array_.get(word(n)), bit(n));
}
void set(unsigned n, bool value) {
check_bounds(n);
unsigned w_index = word(n);
uint64_t w = array_.get(w_index);
if (value)
w = set_bit(w, bit(n));
else
w = clear_bit(w, bit(n));
array_.set(w_index, w);
}
void flush() {
}
void walk_bitset(bitset_visitor &v) const {
bit_visitor vv(v);
damage_visitor dv(v);
array_.visit_values(vv, dv);
}
private:
class bit_visitor {
public:
bit_visitor(bitset_visitor &v)
: v_(v) {
}
void visit(uint32_t word_index, uint64_t word) {
uint32_t bit_index = word_index * 64;
for (unsigned bit = 0; bit < 64; bit++, bit_index++)
v_.visit(bit_index, !!(word & (1 << bit)));
}
private:
bitset_visitor &v_;
};
class damage_visitor {
public:
damage_visitor(bitset_visitor &v)
: v_(v) {
}
void visit(array_detail::damage const &d) {
run<uint32_t> bits(lifted_mult64(d.lost_keys_.begin_),
lifted_mult64(d.lost_keys_.end_));
v_.visit(bits);
}
private:
optional<uint32_t> lifted_mult64(optional<uint32_t> const &m) {
if (!m)
return m;
return optional<uint32_t>(*m * 64);
}
bitset_visitor &v_;
};
void pad_last_block(bool default_value) {
// Set defaults in the final word
if (bit(nr_bits_)) {
unsigned w_index = word(nr_bits_);
uint64_t w = array_.get(w_index);
for (unsigned b = bit(nr_bits_); b < 64; b++)
if (default_value)
w = set_bit(w, b);
else
w = clear_bit(w, b);
array_.set(w_index, w);
}
}
void resize_array(unsigned new_nr_bits, bool default_value) {
unsigned old_nr_words = words_needed(nr_bits_);
unsigned new_nr_words = words_needed(new_nr_bits);
if (new_nr_words < old_nr_words)
throw runtime_error("bitset grow actually asked to shrink");
if (new_nr_words > old_nr_words)
array_.grow(new_nr_words, default_value ? ~0 : 0);
}
unsigned words_needed(unsigned nr_bits) const {
return base::div_up<unsigned>(nr_bits, 64u);
}
unsigned word(unsigned bit) const {
return bit / 64;
}
uint64_t mask(unsigned bit) const {
return 1ull << bit;
}
bool get_bit(uint64_t w, unsigned bit) const {
return w & mask(bit);
}
uint64_t set_bit(uint64_t w, unsigned bit) const {
return w | mask(bit);
}
uint64_t clear_bit(uint64_t w, unsigned bit) const {
return w & (~mask(bit));
}
unsigned bit(unsigned bit) const {
return bit % 64;
}
// The last word may be only partially full, so we have to
// do our own bounds checking rather than relying on array
// to do it.
void check_bounds(unsigned n) const {
if (n >= nr_bits_) {
std::ostringstream str;
str << "bitset index out of bounds ("
<< n << " >= " << nr_bits_ << endl;
throw runtime_error(str.str());
}
}
unsigned nr_bits_;
no_op_ref_counter<uint64_t> rc_;
array<bitset_traits> array_;
};
}
}
//----------------------------------------------------------------
bitset::bitset(tm_ptr tm)
: impl_(new bitset_impl(tm))
{
}
bitset::bitset(tm_ptr tm, block_address root, unsigned nr_bits)
: impl_(new bitset_impl(tm, root, nr_bits))
{
}
block_address
bitset::get_root() const
{
return impl_->get_root();
}
void
bitset::grow(unsigned new_nr_bits, bool default_value)
{
impl_->grow(new_nr_bits, default_value);
}
void
bitset::destroy()
{
impl_->destroy();
}
bool
bitset::get(unsigned n)
{
return impl_->get(n);
}
void
bitset::set(unsigned n, bool value)
{
impl_->set(n, value);
}
void
bitset::flush()
{
impl_->flush();
}
void
bitset::walk_bitset(bitset_visitor &v) const
{
impl_->walk_bitset(v);
}
//----------------------------------------------------------------