1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168

use std::borrow::Borrow;
use std::fmt::{Debug, Formatter};
use std::sync::Arc;

use anyhow::Result;

use crate::algorithms::lazy::{LazyFst2, SimpleHashMapCache};
use crate::algorithms::randgen::randgen_fst_op::RandGenFstOp;
use crate::algorithms::randgen::tr_sampler::TrSampler;
use crate::fst_properties::FstProperties;
use crate::fst_traits::{CoreFst, Fst, FstIterator, MutableFst, StateIterator};
use crate::prelude::randgen::TrSelector;
use crate::{Semiring, StateId, SymbolTable, TrsVec};

type InnerLazyFst<W, F, B, S> = LazyFst2<W, RandGenFstOp<W, F, B, S>, SimpleHashMapCache<W>>;

/// Delayed Fst sampling Fst paths through the input Fst.
pub struct RandGenFst<W: Semiring<Type = f32>, F: Fst<W>, B: Borrow<F>, S: TrSelector>(
    InnerLazyFst<W, F, B, S>,
);

impl<W, F, B, S> CoreFst<W> for RandGenFst<W, F, B, S>
where
    W: Semiring<Type = f32>,
    F: Fst<W>,
    B: Borrow<F>,
    S: TrSelector,
{
    type TRS = TrsVec<W>;

    fn start(&self) -> Option<StateId> {
        self.0.start()
    }

    fn final_weight(&self, state: StateId) -> anyhow::Result<Option<W>> {
        self.0.final_weight(state)
    }

    unsafe fn final_weight_unchecked(&self, state: StateId) -> Option<W> {
        self.0.final_weight_unchecked(state)
    }

    fn num_trs(&self, s: StateId) -> anyhow::Result<usize> {
        self.0.num_trs(s)
    }

    unsafe fn num_trs_unchecked(&self, state: StateId) -> usize {
        self.0.num_trs_unchecked(state)
    }

    fn get_trs(&self, state_id: StateId) -> anyhow::Result<Self::TRS> {
        self.0.get_trs(state_id)
    }

    unsafe fn get_trs_unchecked(&self, state: StateId) -> Self::TRS {
        self.0.get_trs_unchecked(state)
    }

    fn properties(&self) -> FstProperties {
        self.0.properties()
    }

    fn num_input_epsilons(&self, state: StateId) -> anyhow::Result<usize> {
        self.0.num_input_epsilons(state)
    }

    fn num_output_epsilons(&self, state: StateId) -> anyhow::Result<usize> {
        self.0.num_output_epsilons(state)
    }
}

impl<'a, W, F, B, S> StateIterator<'a> for RandGenFst<W, F, B, S>
where
    W: Semiring<Type = f32>,
    F: Fst<W> + 'a,
    B: Borrow<F> + 'a,
    S: TrSelector + 'a,
{
    type Iter = <InnerLazyFst<W, F, B, S> as StateIterator<'a>>::Iter;

    fn states_iter(&'a self) -> Self::Iter {
        self.0.states_iter()
    }
}

impl<'a, W, F, B, S> FstIterator<'a, W> for RandGenFst<W, F, B, S>
where
    W: Semiring<Type = f32>,
    F: Fst<W> + 'a,
    B: Borrow<F> + 'a,
    S: TrSelector + 'a,
{
    type FstIter = <InnerLazyFst<W, F, B, S> as FstIterator<'a, W>>::FstIter;

    fn fst_iter(&'a self) -> Self::FstIter {
        self.0.fst_iter()
    }
}

impl<W, F, B, S> Fst<W> for RandGenFst<W, F, B, S>
where
    W: Semiring<Type = f32>,
    F: Fst<W> + 'static,
    B: Borrow<F> + 'static,
    S: TrSelector + 'static,
{
    fn input_symbols(&self) -> Option<&Arc<SymbolTable>> {
        self.0.input_symbols()
    }

    fn output_symbols(&self) -> Option<&Arc<SymbolTable>> {
        self.0.output_symbols()
    }

    fn set_input_symbols(&mut self, symt: Arc<SymbolTable>) {
        self.0.set_input_symbols(symt)
    }

    fn set_output_symbols(&mut self, symt: Arc<SymbolTable>) {
        self.0.set_output_symbols(symt)
    }

    fn take_input_symbols(&mut self) -> Option<Arc<SymbolTable>> {
        self.0.take_input_symbols()
    }

    fn take_output_symbols(&mut self) -> Option<Arc<SymbolTable>> {
        self.0.take_output_symbols()
    }
}

impl<W, F, B, S> Debug for RandGenFst<W, F, B, S>
where
    W: Semiring<Type = f32>,
    F: Fst<W> + 'static,
    B: Borrow<F> + 'static,
    S: TrSelector + 'static,
{
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        self.0.fmt(f)
    }
}
impl<W, F, B, S> RandGenFst<W, F, B, S>
where
    W: Semiring<Type = f32>,
    F: Fst<W>,
    B: Borrow<F>,
    S: TrSelector,
{
    pub fn new(
        fst: B,
        sampler: TrSampler<W, F, B, S>,
        npath: usize,
        weighted: bool,
        remove_total_weight: bool,
    ) -> Self {
        let isymt = fst.borrow().input_symbols().cloned();
        let osymt = fst.borrow().output_symbols().cloned();
        let fst_op = RandGenFstOp::new(fst, sampler, npath, weighted, remove_total_weight);
        let fst_cache = SimpleHashMapCache::default();
        let lazy_fst = LazyFst2::from_op_and_cache(fst_op, fst_cache, isymt, osymt);
        RandGenFst(lazy_fst)
    }

    pub fn compute<F2: MutableFst<W>>(&self) -> Result<F2> {
        self.0.compute()
    }
}