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kampersanda 2017-11-17 22:56:02 +09:00
parent b5004a9972
commit 4f233d5bbe
2 changed files with 36 additions and 38 deletions
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64
include/xcdat/Trie.hpp
View file

@ -2,6 +2,7 @@
#define XCDAT_TRIE_HPP_
#include <string_view>
#include <xcdat/Trie.hpp>
#include "Trie.hpp"
#include "DacBc.hpp"
@ -10,12 +11,12 @@
namespace xcdat {
// Compressed string dictionary using an improved double-array trie. There are
// two versions of DACs representing BASE/CHECK arrays, selected with the Fast
// parameter.
// two versions of DACs to represent BASE/CHECK arrays in small space. The
// versions can be chosen using the Fast parameter.
template<bool Fast>
class Trie {
public:
using type = Trie<Fast>;
using trie_type = Trie<Fast>;
using bc_type = typename std::conditional<Fast, FastDacBc, DacBc>::type;
static constexpr auto NOT_FOUND = ID_MAX;
@ -40,7 +41,7 @@ public:
~Trie() = default;
// Lookups the ID of a given key. If the key is not registered, otherwise
// returns kNotFound.
// returns NOT_FOUND.
id_type lookup(std::string_view key) const {
size_t pos = 0;
id_type node_id = 0;
@ -66,8 +67,7 @@ public:
return to_key_id_(node_id);
}
// Decodes the key associated with a given ID. The decoded key is appended to
// 'ret' and its length is returned.
// Decodes the key associated with a given ID.
std::string access(id_type id) const {
if (num_keys_ <= id) {
return {};
@ -102,29 +102,29 @@ public:
return dec;
}
// Iterator class for enumerating the keys and IDs included as prefixes of a
// given key, that is, supporting so-called common prefix lookup. It is
// created by using make_prefix_iterator().
// Iterator for enumerating the keys and IDs included as prefixes of a given
// key, that is, supporting so-called common prefix lookup. It is created by
// using make_prefix_iterator().
class PrefixIterator {
public:
PrefixIterator() = default;
// Scans the next key and ID
// Scans the next key. If it does not exist, returns false.
bool next() {
return trie_ != nullptr && trie_->next_prefix_(this);
}
// Gets the key
// Gets the key.
std::string_view key() const {
return {key_.data(), pos_};
};
// Gets the ID
// Gets the ID.
id_type id() const {
return id_;
}
private:
const type* trie_{};
const trie_type* trie_{};
const std::string_view key_{};
size_t pos_{0};
@ -134,40 +134,40 @@ public:
bool begin_flag_{true};
bool end_flag_{false};
PrefixIterator(const type* trie, std::string_view key)
PrefixIterator(const trie_type* trie, std::string_view key)
: trie_{trie}, key_{key} {}
friend class Trie;
};
// Makes PrefixIterator from a given key
// Makes PrefixIterator from a given key.
PrefixIterator make_prefix_iterator(std::string_view key) const {
return PrefixIterator{this, key};
}
// Iterator class for enumerating the keys and IDs starting with prefixes of a
// given key, that is, supporting so-called predictive lookup. It is created
// by using make_predictive_iterator().
// Iterator class for enumerating the keys and IDs starting with prefixes of
// a given key, that is, supporting so-called predictive lookup. It is in
// lexicographical order. It is created by using make_predictive_iterator().
class PredictiveIterator {
public:
PredictiveIterator() = default;
// Scans the next key and ID
// Scans the next key. If it does not exist, returns false.
bool next() {
return trie_ != nullptr && trie_->next_predictive_(this);
}
// Gets the key
// Gets the key.
std::string_view key() const {
return {buf_.data(), buf_.size()};
};
// Gets the ID
// Gets the ID.
id_type id() const {
return id_;
}
private:
const type* trie_{};
const trie_type* trie_{};
const std::string_view key_{};
bool begin_flag_{true};
@ -183,14 +183,15 @@ public:
std::string buf_{};
id_type id_{};
PredictiveIterator(const type* trie, std::string_view key)
PredictiveIterator(const trie_type* trie, std::string_view key)
: trie_{trie}, key_{key} {
buf_.reserve(trie->max_length());
buf_.reserve(trie->max_length_);
}
friend class Trie;
};
// Makes PredictiveIterator from a given key.
PredictiveIterator make_predictive_iterator(std::string_view key) const {
return {this, key};
}
@ -200,12 +201,7 @@ public:
return num_keys_;
}
// Gets the maximum length of registered keys
size_t max_length() const {
return max_length_;
}
// Gets the binary mode
// Gets whether a binary mode or not.
bool bin_mode() const {
return bin_mode_;
}
@ -248,14 +244,16 @@ public:
// Reports the dictionary statistics into an ostream.
void show_stat(std::ostream& os) const {
const auto total_size = size_in_bytes();
os << "basic statistics of xcdat::Trie" << std::endl;
os << "basic statistics of xcdat::Trie<"
<< (Fast ? "true" : "false") << ">" << std::endl;
show_size("\tnum keys: ", num_keys(), os);
show_size("\talphabet size: ", alphabet_size(), os);
show_size("\tnum nodes: ", num_nodes(), os);
show_size("\tnum used nodes:", num_used_nodes(), os);
show_size("\tnum free nodes:", num_free_nodes(), os);
show_size("\tsize in bytes: ", size_in_bytes(), os);
os << "member size statistics of xcdat::Trie" << std::endl;
os << "member size statistics of xcdat::Trie<"
<< (Fast ? "true" : "false") << ">" << std::endl;
show_size_ratio("\tbc: ", bc_.size_in_bytes(), total_size, os);
show_size_ratio("\tterminal_flags:", terminal_flags_.size_in_bytes(),
total_size, os);
@ -278,11 +276,11 @@ public:
write_value(bin_mode_, os);
}
// Swap
void swap(Trie& rhs) {
std::swap(*this, rhs);
}
// Disallows copy and assignment.
Trie(const Trie&) = delete;
Trie& operator=(const Trie&) = delete;

10
include/xcdat/TrieBuilder.hpp
View file

@ -8,11 +8,6 @@ namespace xcdat {
// Double-array trie builder.
class TrieBuilder {
public:
// To avoid undefined traversal
static constexpr id_type TABOO_ID = 1;
// From darts-clone setting
static constexpr id_type FREE_BLOCKS = 16;
// Builds the dictionary from given string keys. The keys must be sorted in
// lexicographical order without duplication. Any error in construction is
// reported by TrieBuilder::Exception. If the keys include the ASCII zero
@ -76,6 +71,11 @@ private:
}
};
// To avoid undefined traversal
static constexpr id_type TABOO_ID = 1;
// From darts-clone setting
static constexpr id_type FREE_BLOCKS = 16;
const std::vector<std::string_view>& keys_;
const id_type block_size_;
const id_type width_L1_;