results in a 2.5x speedup on the stringbench count tests, and a 20x (!)
speedup on the stringbench search/find/contains test, compared to 2.5a2.
for more on the algorithm, see:
http://effbot.org/zone/stringlib.htm
if you get weird results, you can disable the new algoritm by undefining
USE_FAST in Objects/unicodeobject.c.
enjoy /F
speed up splitlines and strip with charsets; etc. rsplit is now as
fast as split in all our tests (reverse takes no time at all), and
splitlines() is nearly as fast as a plain split("\n") in our tests.
and we're not done yet... ;-)
compiler warnings on Windows (signed vs unsigned mismatch
in comparisons). Cleaned that up by switching more locals
to Py_ssize_t. Simplified overflow checking (it can _be_
simpler because while these things are declared as
Py_ssize_t, then should in fact never be negative).
there)
- Add missing DECREFs of inner-scope 'temp' variable
- Add various missing DECREFs by changing 'return NULL' into 'goto onError'
- Avoid double DECREF when last _PyUnicode_Resize() fails
Coverity found one of the missing DECREFs, but oddly enough not the others.
Py_SAFE_DOWNCAST can evaluate its first argument multiple
times in a debug build. This caused two distinct assert-
failures in test_unicode run under a debug build. Rewrote
the code in trivial ways so that multiple evaluation of the
first argument doesn't hurt.
This is how string objects work. u'%f' could use , instead of .
for the decimal point. Now both strings and unicode always use periods.
This is the code that would break:
import locale
locale.setlocale(locale.LC_NUMERIC, 'de_DE')
u'%.1f' % 1.0
assert '1.0' == u'%.1f' % 1.0
I couldn't create a test case which fails, but this fixes the problem.
Will backport.
In C++, it's an error to pass a string literal to a char* function
without a const_cast(). Rather than require every C++ extension
module to put a cast around string literals, fix the API to state the
const-ness.
I focused on parts of the API where people usually pass literals:
PyArg_ParseTuple() and friends, Py_BuildValue(), PyMethodDef, the type
slots, etc. Predictably, there were a large set of functions that
needed to be fixed as a result of these changes. The most pervasive
change was to make the keyword args list passed to
PyArg_ParseTupleAndKewords() to be a const char *kwlist[].
One cast was required as a result of the changes: A type object
mallocs the memory for its tp_doc slot and later frees it.
PyTypeObject says that tp_doc is const char *; but if the type was
created by type_new(), we know it is safe to cast to char *.
[ 1327110 ] wrong TypeError traceback in generator expressions
by removing the code that can stomp on the users' TypeError raised by the
iterable argument to ''.join() -- PySequence_Fast (now?) gives a perfectly
reasonable message itself. Also, a couple of tests.
PyUnicode_DecodeCharmap() the accept a unicode string as the mapping
argument which is used as a mapping table.
This code isn't used by any of the codecs yet.
about illegal code points. The codec now supports PEP 293 style error handlers.
(This is a variant of the Nik Haldimann's patch that detects truncated data)
decoding incomplete input (when the input stream is temporarily exhausted).
codecs.StreamReader now implements buffering, which enables proper
readline support for the UTF-16 decoders. codecs.StreamReader.read()
has a new argument chars which specifies the number of characters to
return. codecs.StreamReader.readline() and codecs.StreamReader.readlines()
have a new argument keepends. Trailing "\n"s will be stripped from the lines
if keepends is false. Added C APIs PyUnicode_DecodeUTF8Stateful and
PyUnicode_DecodeUTF16Stateful.
need to convert str objects from the iterable to unicode. So, if
someone set the system default encoding to something nasty enough,
the conversion process could mutate the input iterable as a side
effect, and PySequence_Fast doesn't hide that from us if the input was
a list. IOW, can't assume the size of PySequence_Fast's result is
invariant across PyUnicode_FromObject() calls.
much to reduce the size of the code, but greatly improves its clarity.
It's also quicker in what's probably the most common case (the argument
iterable is a list). Against it, if the iterable isn't a list or a tuple,
a temp tuple is materialized containing the entire input sequence, and
that's a bigger temp memory burden. Yawn.
1. u1.join([u2]) is u2
2. Be more careful about C-level int overflow.
Since PySequence_Fast() isn't needed to achieve #1, it's not used -- but
the code could sure be simpler if it were.
unicodedata.east_asian_width(). You can still implement your own
simple width() function using it like this:
def width(u):
w = 0
for c in unicodedata.normalize('NFC', u):
cwidth = unicodedata.east_asian_width(c)
if cwidth in ('W', 'F'): w += 2
else: w += 1
return w
iswide() for east asian width manipulation. (Inspired by David
Goodger, Reviewed by Martin v. Loewis)
- Move _PyUnicode_TypeRecord.flags to the end of the struct so that
no padding is added for UCS-4 builds. (Suggested by Martin v. Loewis)
and left shifts. (Thanks to Kalle Svensson for SF patch 849227.)
This addresses most of the remaining semantic changes promised by
PEP 237, except for repr() of a long, which still shows the trailing
'L'. The PEP appears to promise warnings for operations that
changed semantics compared to Python 2.3, but this is not
implemented; we've suffered through enough warnings related to
hex/oct literals and I think it's best to be silent now.
charmaptranslate_makespace() allocated more memory than required for the
next replacement but didn't remember that fact, so memory size was growing
exponentially every time a replacement string is longer that one character.
This fixes SF bug #828737.
If a length-1 Unicode string was in the freelist and it was
uninitialized or pointed to a very large (magnitude) negative number,
the check
unicode_latin1[unicode->str[0]] == unicode
could cause a segmentation violation, e.g. unicode->str[0] is 0xcbcbcbcb.
Fix this in two ways:
1. Change guard befor unicode_latin1[] to test against 256U. If I
understand correctly, the unsigned long used to store UCS4 on my
box was getting converted to a signed long to compare with the
signed constant 256.
2. Change _PyUnicode_New() to make sure the first element of str is
always initialized to zero. There are several places in the code
where the caller can exit with an error before initializing any
of str, which would leave junk in str[0].
Also, silence a compiler warning on pointer vs. int arithmetic.
Bug fix candidate.
The unicode_resize() family only returns -1 or 0 so simply checking
for != 0 is sufficient, but somewhat unclear. Many Python API
functions return < 0 on error, reserving the right to return 0 or 1 on
success. Change the call sites for consistency with these calls.
when an encoding error occurs and the callback name is unknown,
i.e. when the callback has to be called. The problem was that
the fact that the callback has already been looked up was only
recorded in a local variable in charmap_encoding_error(), because
charmap_encoding_error() got it's own copy of the errorHandler
pointer instead of a pointer to the pointer in
PyUnicode_EncodeCharmap().
* Doc - add doc for when functions were added
* UserString
* string object methods
* string module functions
'chars' is used for the last parameter everywhere.
These changes will be backported, since part of the changes
have already been made, but they were inconsistent.
error handers in the Unicode codecs: Negative
positions are treated as being relative to the end of
the input and out of bounds positions result in an
IndexError.
Also update the PEP and include an explanation of
this in the documentation for codecs.register_error.
Fixes a small bug in iconv_codecs: if the position
from the callback is negative *add* it to the size
instead of substracting it.
From SF patch #677429.
types. The special handling for these can now be removed from save_newobj().
Add some testing for this.
Also add support for setting the 'fast' flag on the Python Pickler class,
which suppresses use of the memo.
When mwh added extended slicing, strings and unicode became mappings.
Thus, dict was set which prevented an error when doing:
newstr = 'format without a percent' % string_value
This fix raises an exception again when there are no formats
and % with a string value.
'%2147483647d' % -123 segfaults. This was because an integer overflow
in a comparison caused the string resize to be skipped. After fixing
the overflow, this could call _PyString_Resize() with a negative size,
so I (1) test for that and raise MemoryError instead; (2) also added a
test for negative newsize to _PyString_Resize(), raising SystemError
as for all bad arguments.
An identical bug existed in unicodeobject.c, of course.
Will backport to 2.2.2.
Unicode strings (with arbitrary length) are allowed
as entries in the unicode.translate mapping.
Add a test case for multicharacter replacements.
(Multicharacter replacements were enabled by the
PEP 293 patch)
wrong thing for a unicode subclass when there were zero string
replacements. The example given in the SF bug report was only one way
to trigger this; replacing a string of length >= 2 that's not found is
another. The code would actually write outside allocated memory if
replacement string was longer than the search string.
(I wonder how many more of these are lurking? The unicode code base
is full of wonders.)
Bugfix candidate; this same bug is present in 2.2.1.
currently return inconsistent results for ints and longs; in
particular: hex/oct/%u/%o/%x/%X of negative short ints, and x<<n that
either loses bits or changes sign. (No warnings for repr() of a long,
though that will also change to lose the trailing 'L' eventually.)
This introduces some warnings in the test suite; I'll take care of
those later.
The staticforward define was needed to support certain broken C
compilers (notably SCO ODT 3.0, perhaps early AIX as well) botched the
static keyword when it was used with a forward declaration of a static
initialized structure. Standard C allows the forward declaration with
static, and we've decided to stop catering to broken C compilers. (In
fact, we expect that the compilers are all fixed eight years later.)
I'm leaving staticforward and statichere defined in object.h as
static. This is only for backwards compatibility with C extensions
that might still use it.
XXX I haven't updated the documentation.
[ 400998 ] experimental support for extended slicing on lists
somewhat spruced up and better tested than it was when I wrote it.
Includes docs & tests. The whatsnew section needs expanding, and arrays
should support extended slices -- later.
for 'str' and 'unicode', and can be used instead of
types.StringTypes, e.g. to test whether something is "a string":
isinstance(x, string) is True for Unicode and 8-bit strings. This
is an abstract base class and cannot be instantiated directly.
don't understand how this function works, also beefed up the docs. The
most common usage error is of this form (often spread out across gotos):
if (_PyString_Resize(&s, n) < 0) {
Py_DECREF(s);
s = NULL;
goto outtahere;
}
The error is that if _PyString_Resize runs out of memory, it automatically
decrefs the input string object s (which also deallocates it, since its
refcount must be 1 upon entry), and sets s to NULL. So if the "if"
branch ever triggers, it's an error to call Py_DECREF(s): s is already
NULL! A correct way to write the above is the simpler (and intended)
if (_PyString_Resize(&s, n) < 0)
goto outtahere;
Bugfix candidate.
This implements ideas from Marc-Andre, Martin, Guido and me on Python-Dev.
"Short" Unicode strings are encoded into a "big enough" stack buffer,
then exactly as much string space as they turn out to need is allocated
at the end. This should have speed benefits akin to Martin's "measure
once, allocate once" strategy, but without needing a distinct measuring
pass.
"Long" Unicode strings allocate as much heap space as they could possibly
need (4 x # Unicode chars), and do a realloc at the end to return the
untouched excess. Since the overallocation is likely to be substantial,
this shouldn't burden the platform realloc with unusably small excess
blocks.
Also simplified uses of the PyString_xyz functions. Also added a release-
build check that 4*size doesn't overflow a C int. Sooner or later, that's
going to happen.
http://www.python.org/sf/444708
This adds the optional argument for str.strip
to unicode.strip too and makes it possible
to call str.strip with a unicode argument
and unicode.strip with a str argument.
pointers is a signed type. Changing "allocated" to a signed int makes
undetected overflow more likely, but there was no overflow detection
before either.
Add a method zfill to str, unicode and UserString and change
Lib/string.py accordingly.
This activates the zfill version in unicodeobject.c that was
commented out and implements the same in stringobject.c. It also
adds the test for unicode support in Lib/string.py back in and
uses repr() instead() of str() (as it was before Lib/string.py 1.62)
Fredrik Lundh
Andrew Dalke
Tim Peters
Neal Norwitz
Thomas Wouters
Martin v. Löwis
Anthony Baxter
Georg Brandl
Guido van Rossum
Hye-Shik Chang
Jeremy Hylton
Walter Dörwald
Andrew M. Kuchling
Fred Drake
Michael W. Hudson
Marc-André Lemburg
Skip Montanaro
Thomas Heller
Nicholas Bastin
Raymond Hettinger
Mark Hammond
Neil Schemenauer
Barry Warsaw