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Kaydet (Commit) e2ccf560 authored tarafından Serhiy Storchaka's avatar Serhiy Storchaka
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Issue #19380: Optimized parsing of regular expressions.

üst 5aa47443
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Showing with 122 additions and 150 deletions
Lib/sre_parse.py
Dosyayı görüntüle @ e2ccf560
......@@ -18,12 +18,15 @@ from _sre import MAXREPEAT
SPECIAL_CHARS = ".\\[{()*+?^$|"
REPEAT_CHARS = "*+?{"
DIGITS = set("0123456789")
DIGITS = frozenset("0123456789")
OCTDIGITS = set("01234567")
HEXDIGITS = set("0123456789abcdefABCDEF")
OCTDIGITS = frozenset("01234567")
HEXDIGITS = frozenset("0123456789abcdefABCDEF")
WHITESPACE = set(" \t\n\r\v\f")
WHITESPACE = frozenset(" \t\n\r\v\f")
_REPEATCODES = frozenset((MIN_REPEAT, MAX_REPEAT))
_UNITCODES = frozenset((ANY, RANGE, IN, LITERAL, NOT_LITERAL, CATEGORY))
ESCAPES = {
r"\a": (LITERAL, ord("\a")),
......@@ -153,11 +156,9 @@ class SubPattern:
self.data.append(code)
def getwidth(self):
# determine the width (min, max) for this subpattern
if self.width:
if self.width is not None:
return self.width
lo = hi = 0
UNITCODES = (ANY, RANGE, IN, LITERAL, NOT_LITERAL, CATEGORY)
REPEATCODES = (MIN_REPEAT, MAX_REPEAT)
for op, av in self.data:
if op is BRANCH:
i = MAXREPEAT - 1
......@@ -176,11 +177,11 @@ class SubPattern:
i, j = av[1].getwidth()
lo = lo + i
hi = hi + j
elif op in REPEATCODES:
elif op in _REPEATCODES:
i, j = av[2].getwidth()
lo = lo + i * av[0]
hi = hi + j * av[1]
elif op in UNITCODES:
elif op in _UNITCODES:
lo = lo + 1
hi = hi + 1
elif op == SUCCESS:
......@@ -191,34 +192,31 @@ class SubPattern:
class Tokenizer:
def __init__(self, string):
self.istext = isinstance(string, str)
if not self.istext:
string = str(string, 'latin1')
self.string = string
self.index = 0
self.__next()
def __next(self):
if self.index >= len(self.string):
index = self.index
try:
char = self.string[index]
except IndexError:
self.next = None
return
char = self.string[self.index:self.index+1]
# Special case for the str8, since indexing returns a integer
# XXX This is only needed for test_bug_926075 in test_re.py
if char and not self.istext:
char = chr(char[0])
if char == "\\":
index += 1
try:
c = self.string[self.index + 1]
char += self.string[index]
except IndexError:
raise error("bogus escape (end of line)")
if not self.istext:
c = chr(c)
char = char + c
self.index = self.index + len(char)
self.index = index + 1
self.next = char
def match(self, char, skip=1):
def match(self, char):
if char == self.next:
if skip:
self.__next()
return 1
return 0
self.__next()
return True
return False
def get(self):
this = self.next
self.__next()
......@@ -232,6 +230,17 @@ class Tokenizer:
result += c
self.__next()
return result
def getuntil(self, terminator):
result = ''
while True:
c = self.next
self.__next()
if c is None:
raise error("unterminated name")
if c == terminator:
break
result += c
return result
def tell(self):
return self.index, self.next
def seek(self, index):
......@@ -270,7 +279,7 @@ def _class_escape(source, escape):
if code:
return code
code = CATEGORIES.get(escape)
if code and code[0] == IN:
if code and code[0] is IN:
return code
try:
c = escape[1:2]
......@@ -279,7 +288,7 @@ def _class_escape(source, escape):
escape += source.getwhile(2, HEXDIGITS)
if len(escape) != 4:
raise ValueError
return LITERAL, int(escape[2:], 16) & 0xff
return LITERAL, int(escape[2:], 16)
elif c == "u" and source.istext:
# unicode escape (exactly four digits)
escape += source.getwhile(4, HEXDIGITS)
......@@ -325,7 +334,7 @@ def _escape(source, escape, state):
escape += source.getwhile(2, HEXDIGITS)
if len(escape) != 4:
raise ValueError
return LITERAL, int(escape[2:], 16) & 0xff
return LITERAL, int(escape[2:], 16)
elif c == "u" and source.istext:
# unicode escape (exactly four digits)
escape += source.getwhile(4, HEXDIGITS)
......@@ -347,11 +356,11 @@ def _escape(source, escape, state):
elif c in DIGITS:
# octal escape *or* decimal group reference (sigh)
if source.next in DIGITS:
escape = escape + source.get()
escape += source.get()
if (escape[1] in OCTDIGITS and escape[2] in OCTDIGITS and
source.next in OCTDIGITS):
# got three octal digits; this is an octal escape
escape = escape + source.get()
escape += source.get()
c = int(escape[1:], 8)
if c > 0o377:
raise error('octal escape value %r outside of '
......@@ -370,22 +379,18 @@ def _escape(source, escape, state):
pass
raise error("bogus escape: %s" % repr(escape))
def _parse_sub(source, state, nested=1):
def _parse_sub(source, state, nested=True):
# parse an alternation: a|b|c
items = []
itemsappend = items.append
sourcematch = source.match
while 1:
while True:
itemsappend(_parse(source, state))
if sourcematch("|"):
continue
if not nested:
if not sourcematch("|"):
break
if not source.next or sourcematch(")", 0):
break
else:
raise error("pattern not properly closed")
if nested and source.next is not None and source.next != ")":
raise error("pattern not properly closed")
if len(items) == 1:
return items[0]
......@@ -394,7 +399,7 @@ def _parse_sub(source, state, nested=1):
subpatternappend = subpattern.append
# check if all items share a common prefix
while 1:
while True:
prefix = None
for item in items:
if not item:
......@@ -414,16 +419,12 @@ def _parse_sub(source, state, nested=1):
# check if the branch can be replaced by a character set
for item in items:
if len(item) != 1 or item[0][0] != LITERAL:
if len(item) != 1 or item[0][0] is not LITERAL:
break
else:
# we can store this as a character set instead of a
# branch (the compiler may optimize this even more)
set = []
setappend = set.append
for item in items:
setappend(item[0])
subpatternappend((IN, set))
subpatternappend((IN, [item[0] for item in items]))
return subpattern
subpattern.append((BRANCH, (None, items)))
......@@ -433,21 +434,16 @@ def _parse_sub_cond(source, state, condgroup):
item_yes = _parse(source, state)
if source.match("|"):
item_no = _parse(source, state)
if source.match("|"):
if source.next == "|":
raise error("conditional backref with more than two branches")
else:
item_no = None
if source.next and not source.match(")", 0):
if source.next is not None and source.next != ")":
raise error("pattern not properly closed")
subpattern = SubPattern(state)
subpattern.append((GROUPREF_EXISTS, (condgroup, item_yes, item_no)))
return subpattern
_PATTERNENDERS = set("|)")
_ASSERTCHARS = set("=!<")
_LOOKBEHINDASSERTCHARS = set("=!")
_REPEATCODES = set([MIN_REPEAT, MAX_REPEAT])
def _parse(source, state):
# parse a simple pattern
subpattern = SubPattern(state)
......@@ -457,32 +453,35 @@ def _parse(source, state):
sourceget = source.get
sourcematch = source.match
_len = len
PATTERNENDERS = _PATTERNENDERS
ASSERTCHARS = _ASSERTCHARS
LOOKBEHINDASSERTCHARS = _LOOKBEHINDASSERTCHARS
REPEATCODES = _REPEATCODES
_ord = ord
verbose = state.flags & SRE_FLAG_VERBOSE
while 1:
while True:
if source.next in PATTERNENDERS:
break # end of subpattern
this = sourceget()
this = source.next
if this is None:
break # end of pattern
if this in "|)":
break # end of subpattern
sourceget()
if state.flags & SRE_FLAG_VERBOSE:
if verbose:
# skip whitespace and comments
if this in WHITESPACE:
continue
if this == "#":
while 1:
while True:
this = sourceget()
if this in (None, "\n"):
if this is None or this == "\n":
break
continue
if this and this[0] not in SPECIAL_CHARS:
subpatternappend((LITERAL, ord(this)))
if this[0] == "\\":
code = _escape(source, this, state)
subpatternappend(code)
elif this not in SPECIAL_CHARS:
subpatternappend((LITERAL, _ord(this)))
elif this == "[":
# character set
......@@ -494,39 +493,38 @@ def _parse(source, state):
setappend((NEGATE, None))
# check remaining characters
start = set[:]
while 1:
while True:
this = sourceget()
if this is None:
raise error("unexpected end of regular expression")
if this == "]" and set != start:
break
elif this and this[0] == "\\":
elif this[0] == "\\":
code1 = _class_escape(source, this)
elif this:
code1 = LITERAL, ord(this)
else:
raise error("unexpected end of regular expression")
code1 = LITERAL, _ord(this)
if sourcematch("-"):
# potential range
this = sourceget()
if this is None:
raise error("unexpected end of regular expression")
if this == "]":
if code1[0] is IN:
code1 = code1[1][0]
setappend(code1)
setappend((LITERAL, ord("-")))
setappend((LITERAL, _ord("-")))
break
elif this:
if this[0] == "\\":
code2 = _class_escape(source, this)
else:
code2 = LITERAL, ord(this)
if code1[0] != LITERAL or code2[0] != LITERAL:
raise error("bad character range")
lo = code1[1]
hi = code2[1]
if hi < lo:
raise error("bad character range")
setappend((RANGE, (lo, hi)))
if this[0] == "\\":
code2 = _class_escape(source, this)
else:
raise error("unexpected end of regular expression")
code2 = LITERAL, _ord(this)
if code1[0] != LITERAL or code2[0] != LITERAL:
raise error("bad character range")
lo = code1[1]
hi = code2[1]
if hi < lo:
raise error("bad character range")
setappend((RANGE, (lo, hi)))
else:
if code1[0] is IN:
code1 = code1[1][0]
......@@ -541,7 +539,7 @@ def _parse(source, state):
# XXX: <fl> should add charmap optimization here
subpatternappend((IN, set))
elif this and this[0] in REPEAT_CHARS:
elif this in REPEAT_CHARS:
# repeat previous item
if this == "?":
min, max = 0, 1
......@@ -552,20 +550,20 @@ def _parse(source, state):
min, max = 1, MAXREPEAT
elif this == "{":
if source.next == "}":
subpatternappend((LITERAL, ord(this)))
subpatternappend((LITERAL, _ord(this)))
continue
here = source.tell()
min, max = 0, MAXREPEAT
lo = hi = ""
while source.next in DIGITS:
lo = lo + source.get()
lo += sourceget()
if sourcematch(","):
while source.next in DIGITS:
hi = hi + sourceget()
hi += sourceget()
else:
hi = lo
if not sourcematch("}"):
subpatternappend((LITERAL, ord(this)))
subpatternappend((LITERAL, _ord(this)))
source.seek(here)
continue
if lo:
......@@ -587,7 +585,7 @@ def _parse(source, state):
item = None
if not item or (_len(item) == 1 and item[0][0] == AT):
raise error("nothing to repeat")
if item[0][0] in REPEATCODES:
if item[0][0] in _REPEATCODES:
raise error("multiple repeat")
if sourcematch("?"):
subpattern[-1] = (MIN_REPEAT, (min, max, item))
......@@ -604,18 +602,14 @@ def _parse(source, state):
if sourcematch("?"):
group = 0
# options
if sourcematch("P"):
char = sourceget()
if char is None:
raise error("unexpected end of pattern")
if char == "P":
# python extensions
if sourcematch("<"):
# named group: skip forward to end of name
name = ""
while 1:
char = sourceget()
if char is None:
raise error("unterminated name")
if char == ">":
break
name = name + char
name = source.getuntil(">")
group = 1
if not name:
raise error("missing group name")
......@@ -623,14 +617,7 @@ def _parse(source, state):
raise error("bad character in group name %r" % name)
elif sourcematch("="):
# named backreference
name = ""
while 1:
char = sourceget()
if char is None:
raise error("unterminated name")
if char == ")":
break
name = name + char
name = source.getuntil(")")
if not name:
raise error("missing group name")
if not name.isidentifier():
......@@ -647,27 +634,25 @@ def _parse(source, state):
if char is None:
raise error("unexpected end of pattern")
raise error("unknown specifier: ?P%s" % char)
elif sourcematch(":"):
elif char == ":":
# non-capturing group
group = 2
elif sourcematch("#"):
elif char == "#":
# comment
while 1:
if source.next is None or source.next == ")":
while True:
if source.next is None:
raise error("unbalanced parenthesis")
if sourceget() == ")":
break
sourceget()
if not sourcematch(")"):
raise error("unbalanced parenthesis")
continue
elif source.next in ASSERTCHARS:
elif char in "=!<":
# lookahead assertions
char = sourceget()
dir = 1
if char == "<":
if source.next not in LOOKBEHINDASSERTCHARS:
char = sourceget()
if char is None or char not in "=!":
raise error("syntax error")
dir = -1 # lookbehind
char = sourceget()
p = _parse_sub(source, state)
if not sourcematch(")"):
raise error("unbalanced parenthesis")
......@@ -676,16 +661,9 @@ def _parse(source, state):
else:
subpatternappend((ASSERT_NOT, (dir, p)))
continue
elif sourcematch("("):
elif char == "(":
# conditional backreference group
condname = ""
while 1:
char = sourceget()
if char is None:
raise error("unterminated name")
if char == ")":
break
condname = condname + char
condname = source.getuntil(")")
group = 2
if not condname:
raise error("missing group name")
......@@ -705,12 +683,14 @@ def _parse(source, state):
raise error("bad group number")
if condgroup >= MAXGROUPS:
raise error("the group number is too large")
else:
elif char in FLAGS:
# flags
if not source.next in FLAGS:
raise error("unexpected end of pattern")
state.flags |= FLAGS[char]
while source.next in FLAGS:
state.flags = state.flags | FLAGS[sourceget()]
state.flags |= FLAGS[sourceget()]
verbose = state.flags & SRE_FLAG_VERBOSE
else:
raise error("unexpected end of pattern " + char)
if group:
# parse group contents
if group == 2:
......@@ -728,7 +708,7 @@ def _parse(source, state):
state.closegroup(group)
subpatternappend((SUBPATTERN, (group, p)))
else:
while 1:
while True:
char = sourceget()
if char is None:
raise error("unexpected end of pattern")
......@@ -742,10 +722,6 @@ def _parse(source, state):
elif this == "$":
subpattern.append((AT, AT_END))
elif this and this[0] == "\\":
code = _escape(source, this, state)
subpatternappend(code)
else:
raise error("parser error")
......@@ -776,11 +752,11 @@ def parse(str, flags=0, pattern=None):
p = _parse_sub(source, pattern, 0)
p.pattern.flags = fix_flags(str, p.pattern.flags)
tail = source.get()
if tail == ")":
raise error("unbalanced parenthesis")
elif tail:
raise error("bogus characters at end of regular expression")
if source.next is not None:
if source.next == ")":
raise error("unbalanced parenthesis")
else:
raise error("bogus characters at end of regular expression")
if flags & SRE_FLAG_DEBUG:
p.dump()
......@@ -817,13 +793,7 @@ def parse_template(source, pattern):
if c == "g":
name = ""
if s.match("<"):
while True:
char = sget()
if char is None:
raise error("unterminated group name")
if char == ">":
break
name += char
name = s.getuntil(">")
if not name:
raise error("missing group name")
try:
......
Misc/NEWS
Dosyayı görüntüle @ e2ccf560
......@@ -166,7 +166,9 @@ Core and Builtins
Library
-------
- Issue 1519638: Now unmatched groups are replaced with empty strings in re.sub()
- Issue #19380: Optimized parsing of regular expressions.
- Issue #1519638: Now unmatched groups are replaced with empty strings in re.sub()
and re.subn().
- Issue #18615: sndhdr.what/whathdr now return a namedtuple.
......
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