Package org.antlr.v4.runtime.atn

Class ATNDeserializer

  • public class ATNDeserializer
extends Object
    Deserialize ATNs for JavaTarget; it's complicated by the fact that java requires that we serialize the list of integers as 16 bit characters in a string. Other targets will have an array of ints generated and can simply decode the ints back into an ATN.
    Author:
    Sam Harwell

    • Field Detail

      • SERIALIZED_VERSION

        public static final int SERIALIZED_VERSION

    • Constructor Detail

      • ATNDeserializer

        public ATNDeserializer()

    • Method Detail

      • deserialize

        public ATN deserialize​(char[] data)

      • deserialize

        public ATN deserialize​(int[] data)

      • verifyATN

        protected void verifyATN​(ATN atn)

      • checkCondition

        protected void checkCondition​(boolean condition)

      • checkCondition

        protected void checkCondition​(boolean condition,
                              String message)

      • toInt

        protected static int toInt​(char c)

      • toInt32

        protected static int toInt32​(char[] data,
                             int offset)

      • toInt32

        protected static int toInt32​(int[] data,
                             int offset)

      • edgeFactory

        protected Transition edgeFactory​(ATN atn,
                                 int type,
                                 int src,
                                 int trg,
                                 int arg1,
                                 int arg2,
                                 int arg3,
                                 List<IntervalSet> sets)

      • stateFactory

        protected ATNState stateFactory​(int type,
                                int ruleIndex)

      • encodeIntsWith16BitWords

        public static IntegerList encodeIntsWith16BitWords​(IntegerList data)
        Given a list of integers representing a serialized ATN, encode values too large to fit into 15 bits as two 16bit values. We use the high bit (0x8000_0000) to indicate values requiring two 16 bit words. If the high bit is set, we grab the next value and combine them to get a 31-bit value. The possible input int values are [-1,0x7FFF_FFFF]. | compression/encoding | uint16 count | type | | -------------------------------------------- | ------------ | --------------- | | 0xxxxxxx xxxxxxxx | 1 | uint (15 bit) | | 1xxxxxxx xxxxxxxx yyyyyyyy yyyyyyyy | 2 | uint (16+ bits) | | 11111111 11111111 11111111 11111111 | 2 | int value -1 | This is only used (other than for testing) by SerializedJavaATN to encode ints as char values for the java target, but it is convenient to combine it with the #decodeIntsEncodedAs16BitWords that follows as they are a pair (I did not want to introduce a new class into the runtime). Used only for Java Target.

      • decodeIntsEncodedAs16BitWords

        public static int[] decodeIntsEncodedAs16BitWords​(char[] data16)

      • decodeIntsEncodedAs16BitWords

        public static int[] decodeIntsEncodedAs16BitWords​(char[] data16,
                                                  boolean trimToSize)
        Convert a list of chars (16 uint) that represent a serialized and compressed list of ints for an ATN. This method pairs with encodeIntsWith16BitWords(IntegerList) above. Used only for Java Target.