xref: /aosp_15_r20/external/skia/src/sksl/lex/DFA.h (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
1*c8dee2aaSAndroid Build Coastguard Worker /*
2*c8dee2aaSAndroid Build Coastguard Worker  * Copyright 2017 Google Inc.
3*c8dee2aaSAndroid Build Coastguard Worker  *
4*c8dee2aaSAndroid Build Coastguard Worker  * Use of this source code is governed by a BSD-style license that can be
5*c8dee2aaSAndroid Build Coastguard Worker  * found in the LICENSE file.
6*c8dee2aaSAndroid Build Coastguard Worker  */
7*c8dee2aaSAndroid Build Coastguard Worker 
8*c8dee2aaSAndroid Build Coastguard Worker #ifndef SKSL_DFA
9*c8dee2aaSAndroid Build Coastguard Worker #define SKSL_DFA
10*c8dee2aaSAndroid Build Coastguard Worker 
11*c8dee2aaSAndroid Build Coastguard Worker #include <string>
12*c8dee2aaSAndroid Build Coastguard Worker #include <vector>
13*c8dee2aaSAndroid Build Coastguard Worker 
14*c8dee2aaSAndroid Build Coastguard Worker /**
15*c8dee2aaSAndroid Build Coastguard Worker  * Tables representing a deterministic finite automaton for matching regular expressions.
16*c8dee2aaSAndroid Build Coastguard Worker  */
17*c8dee2aaSAndroid Build Coastguard Worker struct DFA {
DFADFA18*c8dee2aaSAndroid Build Coastguard Worker     DFA(std::vector<int> charMappings, std::vector<std::vector<int>> transitions,
19*c8dee2aaSAndroid Build Coastguard Worker         std::vector<int> accepts)
20*c8dee2aaSAndroid Build Coastguard Worker     : fCharMappings(charMappings)
21*c8dee2aaSAndroid Build Coastguard Worker     , fTransitions(transitions)
22*c8dee2aaSAndroid Build Coastguard Worker     , fAccepts(accepts) {}
23*c8dee2aaSAndroid Build Coastguard Worker 
24*c8dee2aaSAndroid Build Coastguard Worker     // maps chars to the row index of fTransitions, as multiple characters may map to the same row.
25*c8dee2aaSAndroid Build Coastguard Worker     // starting from state s and looking at char c, the new state is
26*c8dee2aaSAndroid Build Coastguard Worker     // fTransitions[fCharMappings[c]][s].
27*c8dee2aaSAndroid Build Coastguard Worker     std::vector<int> fCharMappings;
28*c8dee2aaSAndroid Build Coastguard Worker 
29*c8dee2aaSAndroid Build Coastguard Worker     // one row per character mapping, one column per state
30*c8dee2aaSAndroid Build Coastguard Worker     std::vector<std::vector<int>> fTransitions;
31*c8dee2aaSAndroid Build Coastguard Worker 
32*c8dee2aaSAndroid Build Coastguard Worker     // contains, for each state, the token id we should report when matching ends in that state (-1
33*c8dee2aaSAndroid Build Coastguard Worker     // for no match)
34*c8dee2aaSAndroid Build Coastguard Worker     std::vector<int> fAccepts;
35*c8dee2aaSAndroid Build Coastguard Worker };
36*c8dee2aaSAndroid Build Coastguard Worker 
37*c8dee2aaSAndroid Build Coastguard Worker #endif
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