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https://github.com/yhirose/cpp-fstlib
A single file C++17 header-only Minimal Acyclic Subsequential Transducers, or Finite State Transducers
https://github.com/yhirose/cpp-fstlib
cpp cpp17 finite-state-transducers fst header-only
Last synced: about 2 months ago
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A single file C++17 header-only Minimal Acyclic Subsequential Transducers, or Finite State Transducers
- Host: GitHub
- URL: https://github.com/yhirose/cpp-fstlib
- Owner: yhirose
- License: mit
- Created: 2015-10-14T21:14:23.000Z (about 9 years ago)
- Default Branch: master
- Last Pushed: 2022-10-26T12:33:02.000Z (about 2 years ago)
- Last Synced: 2024-11-01T22:43:00.641Z (2 months ago)
- Topics: cpp, cpp17, finite-state-transducers, fst, header-only
- Language: C++
- Homepage:
- Size: 7.3 MB
- Stars: 54
- Watchers: 4
- Forks: 9
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# cpp-fstlib
[](https://github.com/yhirose/cpp-fstlib/actions)
C++17 header-only FST (finite state transducer) library.
We can use it as [Trie data structure](https://en.wikipedia.org/wiki/Trie).
This library uses the algorithm "[Minimal Acyclic Subsequential Transducers](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.24.3698&rep=rep1&type=pdf)".
## Play cpp-fstlib with cli
```bash
> git clone http://github/yhirose/cpp-fstlib
> cd cpp-fstlib
> make build && cd build
> cmake .. && make
> ./cmd/fst compile /usr/share/dict/words words.fst
> ./cmd/fst search words.fst hello
83713
> ./cmd/fst prefix words.fst helloworld
h: 81421
he: 82951
hell: 83657
hello: 83713
> ./cmd/fst longest words.fst helloworld
hello: 83713
> ./cmd/fst predictive words.fst predictiv
predictive: 153474
predictively: 153475
predictiveness: 153476
> ./cmd/fst fuzzy words.fst fuzzy -ed 2 // Edit distance 2
Suzy: 195759
buzz: 28064
buzzy: 28076
...
> ./cmd/fst spellcheck words.fst thier
their: 0.946667
thir: 0.762667
tier: 0.752
thief: 0.736
trier: 0.704
```
## API reference
```cpp
namespace fst {
enum class Result { Success, EmptyKey, UnsortedKey, DuplicateKey };
std::pair compile(
const std::vector> &input,
std::ostream &os,
bool sorted
);
std::pair compile(
const std::vector> &input,
std::ostream &os
);
std::pair compile(
const std::vector &key_only_input,
std::ostream &os,
bool need_output, // true: map, false: set
bool sorted
);
template class map {
public:
map(const char *byte_code, size_t byte_code_size);
operator bool() const;
bool contains(std::string_view sv) const;
output_t operator[](std::string_view sv) const;
output_t at(std::string_view sv) const;
bool exact_match_search(std::string_view sv, output_t &output) const;
std::vector>
common_prefix_search(std::string_view sv) const;
size_t longest_common_prefix_search(std::string_view sv, output_t &output) const;
std::vector>
predictive_search(std::string_view sv) const;
std::vector>
edit_distance_search(std::string_view sv, size_t max_edits) const;
std::vector>
suggest(std::string_view word) const;
}
class set {
public:
set(const char *byte_code, size_t byte_code_size);
operator bool() const;
bool contains(std::string_view sv) const;
std::vector common_prefix_search(std::string_view sv) const;
size_t longest_common_prefix_search(std::string_view sv) const;
std::vector predictive_search(std::string_view sv) const;
std::vector
edit_distance_search(std::string_view sv, size_t max_edits) const;
std::vector>
suggest(std::string_view word) const;
}
} // namespace fst
```
## API usage
```cpp
const std::vector> items = {
{"hello", "こんにちは!"},
{"world", "世界!"},
{"hello world", "こんにちは世界!"}, // incorrect sort order entry...
};
std::stringstream out;
auto sorted = false; // ask fst::compile to sort entries
auto [result, error_line] = fst::compile(items, out, sorted);
if (result == fst::Result::Success) {
const auto& byte_code = out.str();
fst::map matcher(byte_code.data(), byte_code.size());
if (matcher) {
assert(matcher.contains("hello world"));
assert(!matcher.contains("Hello World"));
assert(matcher["hello"] == "こんにちは!");
auto prefixes = matcher.common_prefix_search("hello world!");
assert(prefixes.size() == 2);
assert(prefixes[0].first == 5);
assert(prefixes[0].second == "こんにちは!");
assert(prefixes[1].first == 11);
assert(prefixes[1].second == "こんにちは世界!");
std::string output;
auto length = matcher.longest_common_prefix_search("hello world!", output);
assert(length == 11);
assert(output == "こんにちは世界!");
auto predictives = matcher.predictive_search("he");
assert(predictives.size() == 2);
assert(predictives[0].first == "hello");
assert(predictives[0].second == "こんにちは!");
assert(predictives[1].first == "hello world");
assert(predictives[1].second == "こんにちは世界!");
std::cout << "[Edit distance 1]" << std::endl;
for (auto [k, o]: matcher.edit_distance_search("hellow", 1)) {
std::cout << "key: " << k << " output: " << o << std::endl;
}
std::cout << "[Suggestions]" << std::endl;
for (auto [r, k, o]: matcher.suggest("hellow")) {
std::cout << "ratio: " << r << " key: " << k << " output: " << o << std::endl;
}
}
}
```
```
[Edit distance 1]
key: hello output: こんにちは
[Suggestions]
ratio: 0.810185 key: hello output: こんにちは
ratio: 0.504132 key: hello world output: こんにちは世界!
ratio: 0.0962963 key: world output: 世界!
```
License
-------
MIT license (© 2022 Yuji Hirose)