Class InputStream

runtime/Python3/src/antlr4/InputStream.py:14–87

class InputStream (object):
    __slots__ = ('name', 'strdata', '_index', 'data', '_size')

    def __init__(self, data: str):
        self.name = "<empty>"
        self.strdata = data
        self._loadString()

    def _loadString(self):
        self._index = 0
        self.data = [ord(c) for c in self.strdata]
        self._size = len(self.data)

    @property
    def index(self):
        return self._index

    @property
    def size(self):
        return self._size

    # Reset the stream so that it's in the same state it was
    #  when the object was created *except* the data array is not
    #  touched.
    #
    def reset(self):
        self._index = 0

    def consume(self):
        if self._index >= self._size:
            assert self.LA(1) == Token.EOF
            raise Exception("cannot consume EOF")
        self._index += 1

    def LA(self, offset: int):
        if offset==0:
            return 0 # undefined
        if offset<0:
            offset += 1 # e.g., translate LA(-1) to use offset=0
        pos = self._index + offset - 1
        if pos < 0 or pos >= self._size: # invalid
            return Token.EOF
        return self.data[pos]

    def LT(self, offset: int):
        return self.LA(offset)

    # mark/release do nothing; we have entire buffer
    def mark(self):
        return -1

    def release(self, marker: int):
        pass

    # consume() ahead until p==_index; can't just set p=_index as we must
    # update line and column. If we seek backwards, just set p
    #
    def seek(self, _index: int):