bpo-30340: Enhanced regular expressions optimization. (#1542)
This increased the performance of matching some patterns up to 25 times.
This commit is contained in:
parent
cbddf58c79
commit
821a9d146b
|
@ -20,6 +20,7 @@ _LITERAL_CODES = {LITERAL, NOT_LITERAL}
|
|||
_REPEATING_CODES = {REPEAT, MIN_REPEAT, MAX_REPEAT}
|
||||
_SUCCESS_CODES = {SUCCESS, FAILURE}
|
||||
_ASSERT_CODES = {ASSERT, ASSERT_NOT}
|
||||
_UNIT_CODES = _LITERAL_CODES | {ANY, IN}
|
||||
|
||||
# Sets of lowercase characters which have the same uppercase.
|
||||
_equivalences = (
|
||||
|
@ -125,7 +126,7 @@ def _compile(code, pattern, flags):
|
|||
elif op in REPEATING_CODES:
|
||||
if flags & SRE_FLAG_TEMPLATE:
|
||||
raise error("internal: unsupported template operator %r" % (op,))
|
||||
elif _simple(av) and op is not REPEAT:
|
||||
if _simple(av[2]):
|
||||
if op is MAX_REPEAT:
|
||||
emit(REPEAT_ONE)
|
||||
else:
|
||||
|
@ -404,10 +405,14 @@ def _bytes_to_codes(b):
|
|||
assert len(a) * a.itemsize == len(b)
|
||||
return a.tolist()
|
||||
|
||||
def _simple(av):
|
||||
# check if av is a "simple" operator
|
||||
lo, hi = av[2].getwidth()
|
||||
return lo == hi == 1 and av[2][0][0] != SUBPATTERN
|
||||
def _simple(p):
|
||||
# check if this subpattern is a "simple" operator
|
||||
if len(p) != 1:
|
||||
return False
|
||||
op, av = p[0]
|
||||
if op is SUBPATTERN:
|
||||
return av[0] is None and _simple(av[-1])
|
||||
return op in _UNIT_CODES
|
||||
|
||||
def _generate_overlap_table(prefix):
|
||||
"""
|
||||
|
|
105
Lib/sre_parse.py
105
Lib/sre_parse.py
|
@ -114,6 +114,7 @@ class SubPattern:
|
|||
data = []
|
||||
self.data = data
|
||||
self.width = None
|
||||
|
||||
def dump(self, level=0):
|
||||
nl = True
|
||||
seqtypes = (tuple, list)
|
||||
|
@ -404,6 +405,15 @@ def _escape(source, escape, state):
|
|||
pass
|
||||
raise source.error("bad escape %s" % escape, len(escape))
|
||||
|
||||
def _uniq(items):
|
||||
if len(set(items)) == len(items):
|
||||
return items
|
||||
newitems = []
|
||||
for item in items:
|
||||
if item not in newitems:
|
||||
newitems.append(item)
|
||||
return newitems
|
||||
|
||||
def _parse_sub(source, state, verbose, nested=True):
|
||||
# parse an alternation: a|b|c
|
||||
|
||||
|
@ -420,7 +430,6 @@ def _parse_sub(source, state, verbose, nested=True):
|
|||
return items[0]
|
||||
|
||||
subpattern = SubPattern(state)
|
||||
subpatternappend = subpattern.append
|
||||
|
||||
# check if all items share a common prefix
|
||||
while True:
|
||||
|
@ -437,35 +446,31 @@ def _parse_sub(source, state, verbose, nested=True):
|
|||
# move it out of the branch
|
||||
for item in items:
|
||||
del item[0]
|
||||
subpatternappend(prefix)
|
||||
subpattern.append(prefix)
|
||||
continue # check next one
|
||||
break
|
||||
|
||||
# check if the branch can be replaced by a character set
|
||||
set = []
|
||||
for item in items:
|
||||
if len(item) != 1 or item[0][0] is not LITERAL:
|
||||
if len(item) != 1:
|
||||
break
|
||||
op, av = item[0]
|
||||
if op is LITERAL:
|
||||
set.append((op, av))
|
||||
elif op is IN and av[0][0] is not NEGATE:
|
||||
set.extend(av)
|
||||
else:
|
||||
break
|
||||
else:
|
||||
# we can store this as a character set instead of a
|
||||
# branch (the compiler may optimize this even more)
|
||||
subpatternappend((IN, [item[0] for item in items]))
|
||||
subpattern.append((IN, _uniq(set)))
|
||||
return subpattern
|
||||
|
||||
subpattern.append((BRANCH, (None, items)))
|
||||
return subpattern
|
||||
|
||||
def _parse_sub_cond(source, state, condgroup, verbose):
|
||||
item_yes = _parse(source, state, verbose)
|
||||
if source.match("|"):
|
||||
item_no = _parse(source, state, verbose)
|
||||
if source.next == "|":
|
||||
raise source.error("conditional backref with more than two branches")
|
||||
else:
|
||||
item_no = None
|
||||
subpattern = SubPattern(state)
|
||||
subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
|
||||
return subpattern
|
||||
|
||||
def _parse(source, state, verbose, first=False):
|
||||
# parse a simple pattern
|
||||
subpattern = SubPattern(state)
|
||||
|
@ -511,16 +516,14 @@ def _parse(source, state, verbose, first=False):
|
|||
setappend = set.append
|
||||
## if sourcematch(":"):
|
||||
## pass # handle character classes
|
||||
if sourcematch("^"):
|
||||
setappend((NEGATE, None))
|
||||
negate = sourcematch("^")
|
||||
# check remaining characters
|
||||
start = set[:]
|
||||
while True:
|
||||
this = sourceget()
|
||||
if this is None:
|
||||
raise source.error("unterminated character set",
|
||||
source.tell() - here)
|
||||
if this == "]" and set != start:
|
||||
if this == "]" and set:
|
||||
break
|
||||
elif this[0] == "\\":
|
||||
code1 = _class_escape(source, this)
|
||||
|
@ -556,13 +559,19 @@ def _parse(source, state, verbose, first=False):
|
|||
code1 = code1[1][0]
|
||||
setappend(code1)
|
||||
|
||||
set = _uniq(set)
|
||||
# XXX: <fl> should move set optimization to compiler!
|
||||
if _len(set)==1 and set[0][0] is LITERAL:
|
||||
subpatternappend(set[0]) # optimization
|
||||
elif _len(set)==2 and set[0][0] is NEGATE and set[1][0] is LITERAL:
|
||||
subpatternappend((NOT_LITERAL, set[1][1])) # optimization
|
||||
if _len(set) == 1 and set[0][0] is LITERAL:
|
||||
# optimization
|
||||
if negate:
|
||||
subpatternappend((NOT_LITERAL, set[0][1]))
|
||||
else:
|
||||
subpatternappend(set[0])
|
||||
else:
|
||||
# XXX: <fl> should add charmap optimization here
|
||||
if negate:
|
||||
set.insert(0, (NEGATE, None))
|
||||
# charmap optimization can't be added here because
|
||||
# global flags still are not known
|
||||
subpatternappend((IN, set))
|
||||
|
||||
elif this in REPEAT_CHARS:
|
||||
|
@ -579,6 +588,7 @@ def _parse(source, state, verbose, first=False):
|
|||
if source.next == "}":
|
||||
subpatternappend((LITERAL, _ord(this)))
|
||||
continue
|
||||
|
||||
min, max = 0, MAXREPEAT
|
||||
lo = hi = ""
|
||||
while source.next in DIGITS:
|
||||
|
@ -592,6 +602,7 @@ def _parse(source, state, verbose, first=False):
|
|||
subpatternappend((LITERAL, _ord(this)))
|
||||
source.seek(here)
|
||||
continue
|
||||
|
||||
if lo:
|
||||
min = int(lo)
|
||||
if min >= MAXREPEAT:
|
||||
|
@ -610,12 +621,16 @@ def _parse(source, state, verbose, first=False):
|
|||
item = subpattern[-1:]
|
||||
else:
|
||||
item = None
|
||||
if not item or (_len(item) == 1 and item[0][0] is AT):
|
||||
if not item or item[0][0] is AT:
|
||||
raise source.error("nothing to repeat",
|
||||
source.tell() - here + len(this))
|
||||
if item[0][0] in _REPEATCODES:
|
||||
raise source.error("multiple repeat",
|
||||
source.tell() - here + len(this))
|
||||
if item[0][0] is SUBPATTERN:
|
||||
group, add_flags, del_flags, p = item[0][1]
|
||||
if group is None and not add_flags and not del_flags:
|
||||
item = p
|
||||
if sourcematch("?"):
|
||||
subpattern[-1] = (MIN_REPEAT, (min, max, item))
|
||||
else:
|
||||
|
@ -628,7 +643,6 @@ def _parse(source, state, verbose, first=False):
|
|||
start = source.tell() - 1
|
||||
group = True
|
||||
name = None
|
||||
condgroup = None
|
||||
add_flags = 0
|
||||
del_flags = 0
|
||||
if sourcematch("?"):
|
||||
|
@ -660,6 +674,7 @@ def _parse(source, state, verbose, first=False):
|
|||
state.checklookbehindgroup(gid, source)
|
||||
subpatternappend((GROUPREF, gid))
|
||||
continue
|
||||
|
||||
else:
|
||||
char = sourceget()
|
||||
if char is None:
|
||||
|
@ -678,6 +693,7 @@ def _parse(source, state, verbose, first=False):
|
|||
if sourceget() == ")":
|
||||
break
|
||||
continue
|
||||
|
||||
elif char in "=!<":
|
||||
# lookahead assertions
|
||||
dir = 1
|
||||
|
@ -704,10 +720,10 @@ def _parse(source, state, verbose, first=False):
|
|||
else:
|
||||
subpatternappend((ASSERT_NOT, (dir, p)))
|
||||
continue
|
||||
|
||||
elif char == "(":
|
||||
# conditional backreference group
|
||||
condname = source.getuntil(")")
|
||||
group = None
|
||||
if condname.isidentifier():
|
||||
condgroup = state.groupdict.get(condname)
|
||||
if condgroup is None:
|
||||
|
@ -728,6 +744,19 @@ def _parse(source, state, verbose, first=False):
|
|||
msg = "invalid group reference %d" % condgroup
|
||||
raise source.error(msg, len(condname) + 1)
|
||||
state.checklookbehindgroup(condgroup, source)
|
||||
item_yes = _parse(source, state, verbose)
|
||||
if source.match("|"):
|
||||
item_no = _parse(source, state, verbose)
|
||||
if source.next == "|":
|
||||
raise source.error("conditional backref with more than two branches")
|
||||
else:
|
||||
item_no = None
|
||||
if not source.match(")"):
|
||||
raise source.error("missing ), unterminated subpattern",
|
||||
source.tell() - start)
|
||||
subpatternappend((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
|
||||
continue
|
||||
|
||||
elif char in FLAGS or char == "-":
|
||||
# flags
|
||||
flags = _parse_flags(source, state, char)
|
||||
|
@ -744,6 +773,7 @@ def _parse(source, state, verbose, first=False):
|
|||
if (state.flags & SRE_FLAG_VERBOSE) and not verbose:
|
||||
raise Verbose
|
||||
continue
|
||||
|
||||
add_flags, del_flags = flags
|
||||
group = None
|
||||
else:
|
||||
|
@ -756,12 +786,9 @@ def _parse(source, state, verbose, first=False):
|
|||
group = state.opengroup(name)
|
||||
except error as err:
|
||||
raise source.error(err.msg, len(name) + 1) from None
|
||||
if condgroup:
|
||||
p = _parse_sub_cond(source, state, condgroup, verbose)
|
||||
else:
|
||||
sub_verbose = ((verbose or (add_flags & SRE_FLAG_VERBOSE)) and
|
||||
not (del_flags & SRE_FLAG_VERBOSE))
|
||||
p = _parse_sub(source, state, sub_verbose)
|
||||
sub_verbose = ((verbose or (add_flags & SRE_FLAG_VERBOSE)) and
|
||||
not (del_flags & SRE_FLAG_VERBOSE))
|
||||
p = _parse_sub(source, state, sub_verbose)
|
||||
if not source.match(")"):
|
||||
raise source.error("missing ), unterminated subpattern",
|
||||
source.tell() - start)
|
||||
|
@ -773,11 +800,19 @@ def _parse(source, state, verbose, first=False):
|
|||
subpatternappend((AT, AT_BEGINNING))
|
||||
|
||||
elif this == "$":
|
||||
subpattern.append((AT, AT_END))
|
||||
subpatternappend((AT, AT_END))
|
||||
|
||||
else:
|
||||
raise AssertionError("unsupported special character %r" % (char,))
|
||||
|
||||
# unpack non-capturing groups
|
||||
for i in range(len(subpattern))[::-1]:
|
||||
op, av = subpattern[i]
|
||||
if op is SUBPATTERN:
|
||||
group, add_flags, del_flags, p = av
|
||||
if group is None and not add_flags and not del_flags:
|
||||
subpattern[i: i+1] = p
|
||||
|
||||
return subpattern
|
||||
|
||||
def _parse_flags(source, state, char):
|
||||
|
|
|
@ -1695,20 +1695,18 @@ class ReTests(unittest.TestCase):
|
|||
dump = '''\
|
||||
SUBPATTERN 1 0 0
|
||||
LITERAL 46
|
||||
SUBPATTERN None 0 0
|
||||
BRANCH
|
||||
IN
|
||||
LITERAL 99
|
||||
LITERAL 104
|
||||
OR
|
||||
LITERAL 112
|
||||
LITERAL 121
|
||||
SUBPATTERN None 0 0
|
||||
GROUPREF_EXISTS 1
|
||||
AT AT_END
|
||||
ELSE
|
||||
LITERAL 58
|
||||
LITERAL 32
|
||||
BRANCH
|
||||
IN
|
||||
LITERAL 99
|
||||
LITERAL 104
|
||||
OR
|
||||
LITERAL 112
|
||||
LITERAL 121
|
||||
GROUPREF_EXISTS 1
|
||||
AT AT_END
|
||||
ELSE
|
||||
LITERAL 58
|
||||
LITERAL 32
|
||||
'''
|
||||
self.assertEqual(out.getvalue(), dump)
|
||||
# Debug output is output again even a second time (bypassing
|
||||
|
|
|
@ -326,6 +326,9 @@ Library
|
|||
- bpo-30048: Fixed ``Task.cancel()`` can be ignored when the task is
|
||||
running coroutine and the coroutine returned without any more ``await``.
|
||||
|
||||
- bpo-30340: Enhanced regular expressions optimization. This increased
|
||||
the performance of matching some patterns up to 25 times.
|
||||
|
||||
- bpo-30298: Weaken the condition of deprecation warnings for inline modifiers.
|
||||
Now allowed several subsequential inline modifiers at the start of the
|
||||
pattern (e.g. ``'(?i)(?s)...'``). In verbose mode whitespaces and comments
|
||||
|
|
Loading…
Reference in New Issue