/usr/lib/python2.7/dist-packages/antlr3/dfa.py is in python-antlr3 3.5.2-1.
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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 | """ANTLR3 runtime package"""
# begin[licence]
#
# [The "BSD licence"]
# Copyright (c) 2005-2008 Terence Parr
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# end[licensc]
from antlr3.constants import EOF
from antlr3.exceptions import NoViableAltException, BacktrackingFailed
class DFA(object):
"""@brief A DFA implemented as a set of transition tables.
Any state that has a semantic predicate edge is special; those states
are generated with if-then-else structures in a specialStateTransition()
which is generated by cyclicDFA template.
"""
def __init__(
self,
recognizer, decisionNumber,
eot, eof, min, max, accept, special, transition
):
## Which recognizer encloses this DFA? Needed to check backtracking
self.recognizer = recognizer
self.decisionNumber = decisionNumber
self.eot = eot
self.eof = eof
self.min = min
self.max = max
self.accept = accept
self.special = special
self.transition = transition
def predict(self, input):
"""
From the input stream, predict what alternative will succeed
using this DFA (representing the covering regular approximation
to the underlying CFL). Return an alternative number 1..n. Throw
an exception upon error.
"""
mark = input.mark()
s = 0 # we always start at s0
try:
for _ in xrange(50000):
#print "***Current state = %d" % s
specialState = self.special[s]
if specialState >= 0:
#print "is special"
s = self.specialStateTransition(specialState, input)
if s == -1:
self.noViableAlt(s, input)
return 0
input.consume()
continue
if self.accept[s] >= 1:
#print "accept state for alt %d" % self.accept[s]
return self.accept[s]
# look for a normal char transition
c = input.LA(1)
#print "LA = %d (%r)" % (c, unichr(c) if c >= 0 else 'EOF')
#print "range = %d..%d" % (self.min[s], self.max[s])
if c >= self.min[s] and c <= self.max[s]:
# move to next state
snext = self.transition[s][c-self.min[s]]
#print "in range, next state = %d" % snext
if snext < 0:
#print "not a normal transition"
# was in range but not a normal transition
# must check EOT, which is like the else clause.
# eot[s]>=0 indicates that an EOT edge goes to another
# state.
if self.eot[s] >= 0: # EOT Transition to accept state?
#print "EOT trans to accept state %d" % self.eot[s]
s = self.eot[s]
input.consume()
# TODO: I had this as return accept[eot[s]]
# which assumed here that the EOT edge always
# went to an accept...faster to do this, but
# what about predicated edges coming from EOT
# target?
continue
#print "no viable alt"
self.noViableAlt(s, input)
return 0
s = snext
input.consume()
continue
if self.eot[s] >= 0:
#print "EOT to %d" % self.eot[s]
s = self.eot[s]
input.consume()
continue
# EOF Transition to accept state?
if c == EOF and self.eof[s] >= 0:
#print "EOF Transition to accept state %d" \
# % self.accept[self.eof[s]]
return self.accept[self.eof[s]]
# not in range and not EOF/EOT, must be invalid symbol
self.noViableAlt(s, input)
return 0
else:
raise RuntimeError("DFA bang!")
finally:
input.rewind(mark)
def noViableAlt(self, s, input):
if self.recognizer._state.backtracking > 0:
raise BacktrackingFailed
nvae = NoViableAltException(
self.getDescription(),
self.decisionNumber,
s,
input
)
self.error(nvae)
raise nvae
def error(self, nvae):
"""A hook for debugging interface"""
pass
def specialStateTransition(self, s, input):
return -1
def getDescription(self):
return "n/a"
## def specialTransition(self, state, symbol):
## return 0
def unpack(cls, string):
"""@brief Unpack the runlength encoded table data.
Terence implemented packed table initializers, because Java has a
size restriction on .class files and the lookup tables can grow
pretty large. The generated JavaLexer.java of the Java.g example
would be about 15MB with uncompressed array initializers.
Python does not have any size restrictions, but the compilation of
such large source files seems to be pretty memory hungry. The memory
consumption of the python process grew to >1.5GB when importing a
15MB lexer, eating all my swap space and I was to impacient to see,
if it could finish at all. With packed initializers that are unpacked
at import time of the lexer module, everything works like a charm.
"""
ret = []
for i in range(len(string) / 2):
(n, v) = ord(string[i*2]), ord(string[i*2+1])
# Is there a bitwise operation to do this?
if v == 0xFFFF:
v = -1
ret += [v] * n
return ret
unpack = classmethod(unpack)
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