/*! \param i Argument for the length of the prefix v[0..i-1], with \f$0\leq i \leq size()\f$.
\returns Number of 1-bits in the prefix [0..i-1] of the original bit_vector.
\par Time complexity
\f$ \Order{ sample\_rate of the rrr\_vector} \f$
*/
const size_type rank(size_type i)const {
assert(m_v != nullptr);
assert(i <= m_v->size());
size_type bt_idx = i/t_bs;
size_type sample_pos = bt_idx/t_k;
size_type btnrp = m_v->m_btnrp[ sample_pos ];
size_type rank = m_v->m_rank[ sample_pos ];
if (sample_pos+1 < m_v->m_rank.size()) {
size_type diff_rank = m_v->m_rank[ sample_pos+1 ] - rank;
#ifndef RRR_NO_OPT
if (diff_rank == (size_type)0) {
return rank_support_rrr_trait<t_b>::adjust_rank(rank, i);
} else if (diff_rank == (size_type)t_bs*t_k) {
return rank_support_rrr_trait<t_b>::adjust_rank(
rank + i - sample_pos*t_k*t_bs, i);
}
#endif
}
const bool inv = m_v->m_invert[ sample_pos ];
for (size_type j = sample_pos*t_k; j < bt_idx; ++j) {
uint16_t r = m_v->m_bt[j];
rank += (inv ? t_bs - r: r);
btnrp += rrr_helper_type::space_for_bt(r);
}
uint16_t off = i % t_bs;
if (!off) { // needed for special case: if i=size() is a multiple of t_bs
// the access to m_bt would cause a invalid memory access
return rank_support_rrr_trait<t_b>::adjust_rank(rank, i);
}
uint16_t bt = inv ? t_bs - m_v->m_bt[ bt_idx ] : m_v->m_bt[ bt_idx ];
uint16_t btnrlen = rrr_helper_type::space_for_bt(bt);
number_type btnr = rrr_helper_type::decode_btnr(m_v->m_btnr, btnrp, btnrlen);
uint16_t popcnt = rrr_helper_type::decode_popcount(bt, btnr, off);
return rank_support_rrr_trait<t_b>::adjust_rank(rank + popcnt, i);
}
const size_type size()const {
return m_v->size();
}
/*! \param v A node.
*/
bool is_leaf(const node_type& v) const {
// node is the last leaf or has no children, so m_bv[v.pos]==1
return (v.pos+1 == m_bv.size()) or m_bv[v.pos+1];
}
//! Returns the number of nodes in the tree.
size_type nodes()const {
return (m_bv.size()+1)/2;
}
//! Returns the number of nodes in the tree.
size_type nodes()const {
return m_bv.size()+1/2;
}
