1 /*
2  * [The "BSD license"]
3  *  Copyright (c) 2016 Terence Parr
4  *  Copyright (c) 2016 Sam Harwell
5  *  All rights reserved.
6  *
7  *  Redistribution and use in source and binary forms, with or without
8  *  modification, are permitted provided that the following conditions
9  *  are met:
10  *
11  *  1. Redistributions of source code must retain the above copyright
12  *     notice, this list of conditions and the following disclaimer.
13  *  2. Redistributions in binary form must reproduce the above copyright
14  *     notice, this list of conditions and the following disclaimer in the
15  *     documentation and/or other materials provided with the distribution.
16  *  3. The name of the author may not be used to endorse or promote products
17  *     derived from this software without specific prior written permission.
18  *
19  *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 module antlr.v4.runtime.atn.ATNState;
32 
33 import std.stdio;
34 import std.conv;
35 import std.array;
36 import antlr.v4.runtime.atn.StateNames;
37 import antlr.v4.runtime.atn.Transition;
38 import antlr.v4.runtime.atn.ATN;
39 import antlr.v4.runtime.misc.IntervalSet;
40 import std.algorithm.mutation: remove;
41 
42 /**
43  * The following images show the relation of states and
44  * {@link ATNState#transitions} for various grammar constructs.
45  */
46 abstract class ATNState
47 {
48 
49     public static immutable int INITIAL_NUM_TRANSITIONS = 4;
50 
51     public static immutable int INVALID_STATE_NUMBER = -1;
52 
53     /**
54      * @uml
55      * Which ATN are we in?
56      */
57     public ATN atn = null;
58 
59     public int stateNumber = INVALID_STATE_NUMBER;
60 
61     /**
62      * @uml
63      * at runtime, we don't have Rule objects
64      */
65     public int ruleIndex;
66 
67     public bool epsilonOnlyTransitions = false;
68 
69     /**
70      * @uml
71      * Track the transitions emanating from this ATN state.
72      */
73     public Transition[] transitions;
74 
75     /**
76      * @uml
77      * Used to cache lookahead during parsing, not used during construction
78      */
79     public IntervalSet nextTokenWithinRule;
80 
81     /**
82      * @uml
83      * @read
84      * @write
85      */
86     private Transition[] optimizedTransitions_;
87 
88     /**
89      * @uml
90      * @pure
91      * @safe
92      */
93     public int hashCode() @safe pure
94     {
95         return stateNumber;
96     }
97 
98     /**
99      * @uml
100      * @pure
101      * @safe
102      */
103     public bool equals(Object o) @safe pure
104     {
105         return stateNumber==(cast(ATNState)o).stateNumber;
106     }
107 
108     /**
109      * @uml
110      * @pure
111      * @safe
112      */
113     public bool isNonGreedyExitState() @safe pure
114     {
115         return false;
116     }
117 
118     /**
119      * @uml
120      * @pure
121      * @safe
122      * @override
123      */
124     public override string toString() @safe pure
125     {
126         return to!string(stateNumber);
127     }
128 
129     /**
130      * @uml
131      * @pure
132      * @safe
133      */
134     public Transition[] getTransitions() @safe pure
135     {
136         return transitions.dup;
137     }
138 
139     /**
140      * @uml
141      * @pure
142      * @safe
143      */
144     public int getNumberOfTransitions() @safe pure
145     {
146         return to!int(transitions.length);
147     }
148 
149     public void addTransition(Transition e)
150     {
151         if (transitions.length == 0) {
152             epsilonOnlyTransitions = e.isEpsilon;
153         }
154         else
155             if (epsilonOnlyTransitions != e.isEpsilon()) {
156                 stderr.writefln("ATN state %1$s has both epsilon and non-epsilon transitions.\n", stateNumber);
157                 epsilonOnlyTransitions = false;
158             }
159         transitions ~= e;
160     }
161 
162     public Transition transition(int i)
163     {
164         return transitions[i];
165     }
166 
167     public void setTransition(int i, Transition e)
168     {
169         transitions[i] = e;
170     }
171 
172     public Transition removeTransition(int index)
173     {
174         auto t = transitions[index];
175         transitions = transitions[0..index] ~ transitions[index+1..$];
176         return t;
177     }
178 
179     abstract public int getStateType();
180 
181     public bool onlyHasEpsilonTransitions()
182     {
183         return epsilonOnlyTransitions;
184     }
185 
186     public void setRuleIndex(int ruleIndex)
187     {
188         this.ruleIndex = ruleIndex;
189     }
190 
191     public bool isOptimized()
192     {
193         return optimizedTransitions != transitions;
194     }
195 
196     public size_t numberOfOptimizedTransitions()
197     {
198         return optimizedTransitions.length;
199     }
200 
201     public Transition getOptimizedTransition(size_t i)
202     {
203         return optimizedTransitions[i];
204     }
205 
206     public void addOptimizedTransition(Transition e)
207     {
208         if (!isOptimized)
209             {
210                 optimizedTransitions_.length = 0;
211             }
212             optimizedTransitions_ ~= e;
213     }
214 
215     public void setOptimizedTransition(size_t i, Transition e)
216     {
217         if (!isOptimized)
218             {
219                 assert(false, "InvalidOperationException");
220             }
221             optimizedTransitions_[i] = e;
222     }
223 
224     public void removeOptimizedTransition(size_t i)
225     {
226         if (!isOptimized)
227             {
228                 assert(false, "InvalidOperationException");
229             }
230             optimizedTransitions_ = optimizedTransitions_.remove(i);
231     }
232 
233     public this()
234     {
235         optimizedTransitions = transitions.dup;
236     }
237 
238     public final Transition[] optimizedTransitions()
239     {
240         return this.optimizedTransitions_.dup;
241     }
242 
243     public final void optimizedTransitions(Transition[] optimizedTransitions)
244     {
245         this.optimizedTransitions_ = optimizedTransitions.dup;
246     }
247 
248 }