Properly bound reps for machine parser

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixed
 
+* Properly bound repetitions for machine parsers ([#53])
 * Group quantized 2+ char literals in regex optimization ([#54])
 
 
@@ -219,4 +220,5 @@ descent parser and a work-in-progress state-machine parser.
 [#38]: https://github.com/goodmami/pe/issues/38
 [#44]: https://github.com/goodmami/pe/issues/44
 [#46]: https://github.com/goodmami/pe/issues/46
+[#53]: https://github.com/goodmami/pe/issues/53
 [#54]: https://github.com/goodmami/pe/issues/54

pe/_cy_machine.pyx

@@ -272,7 +272,8 @@ cdef class _Parser:
                 continue
 
             elif instr.opcode == UPDATE:
-                if instr.maxcount == -1 or state.count < instr.maxcount:
+                state.count += 1
+                if instr.maxcount < 0 or state.count < instr.maxcount:
                     state.pos = pos
                     state.argidx = len(args)
                     state.kwidx = len(kwargs)
@@ -433,7 +434,7 @@ def _loop(defn, mincount, maxcount):
         *(pi.copy() for _ in range(mincount) for pi in pis),
         Instruction(BRANCH, len(pis) + 2),
         *pis,
-        Instruction(UPDATE, -len(pis), maxcount=maxcount)
+        Instruction(UPDATE, -len(pis), maxcount=(maxcount - mincount))
     ]
 
 

pe/_py_machine.py

@@ -205,8 +205,9 @@ def _match(  # noqa: C901
 
         elif opcode == UPDATE:
             next_idx, _, count, prev_mark, _, _ = pop()
-            if maxcount == -1 or count < maxcount:
-                push((next_idx, pos, count + 1, prev_mark, len(args), len(kwargs)))
+            count += 1
+            if maxcount < 0 or count < maxcount:
+                push((next_idx, pos, count, prev_mark, len(args), len(kwargs)))
                 idx += oploc
             else:
                 idx += 1
@@ -355,7 +356,7 @@ def _loop(defn, mincount: int, maxcount: int):
     return [*(pis * mincount),  # risk of billion laughs attack
             Instruction(BRANCH, len(pis) + 2),
             *pis,
-            Instruction(UPDATE, -len(pis), maxcount=maxcount)]
+            Instruction(UPDATE, -len(pis), maxcount=(maxcount - mincount))]
 
 
 def _sym(defn):

test/test_parsers.py

@@ -91,6 +91,7 @@
                               'aabbcc', 0, 3,    _blank),
     ('Rpt3', Rpt(abc, min=3), 'aaxx',   0, FAIL, None),
     ('Rpt4', Rpt(abc, max=1), 'aabbcc', 0, 1,    _blank),
+    ('Rpt5', Rpt('a', max=2), 'aaaaaa', 0, 2,    _blank),
 
     ('And0', And(abc),        'a',      0, 0,    _blank),
     ('And1', And(abc),        'd',      0, FAIL, None),