This avoids possible buffer overreads when int(), float(), compile(), exec()
and eval() are passed bytes-like objects. Similar code is removed from the
complex() constructor, where it was not reachable.
Patch by John Leitch, Serhiy Storchaka and Martin Panter.
This changes the main documentation, doc strings, source code comments, and a
couple error messages in the test suite. In some cases the word was removed
or edited some other way to fix the grammar.
Don't add parenthesis to type names. Add also quotes around the type names.
Before:
TypeError: unorderable types: int() < NoneType()
After:
TypeError: '<' not supported between instances of 'int' and 'NoneType'
* Don't overallocate by 400% when recode is needed: only overallocate on demand
using _PyBytesWriter.
* Use _PyLong_DigitValue to convert hexadecimal digit to int
* Create _PyBytes_DecodeEscapeRecode() subfunction
Issue #25401: Optimize bytes.fromhex() and bytearray.fromhex(): they are now
between 2x and 3.5x faster. Changes:
* Use a fast-path working on a char* string for ASCII string
* Use a slow-path for non-ASCII string
* Replace slow hex_digit_to_int() function with a O(1) lookup in
_PyLong_DigitValue precomputed table
* Use _PyBytesWriter API to handle the buffer
* Add unit tests to check the error position in error messages
Issue #25399: Don't create temporary bytes objects: modify _PyBytes_Format() to
create work directly on bytearray objects.
* Rename _PyBytes_Format() to _PyBytes_FormatEx() just in case if something
outside CPython uses it
* _PyBytes_FormatEx() now uses (char*, Py_ssize_t) for the input string, so
bytearray_format() doesn't need tot create a temporary input bytes object
* Add use_bytearray parameter to _PyBytes_FormatEx() which is passed to
_PyBytesWriter, to create a bytearray buffer instead of a bytes buffer
Most formatting operations are now between 2.5 and 5 times faster.
* Add much more unit tests on PyBytes_FromFormatV()
* Remove the first loop to compute the length of the output string
* Use _PyBytesWriter to handle the bytes buffer, use overallocation
* Cleanup the code to make simpler and easier to review
Don't require _PyBytesWriter pointer to be a "char *". Same change for
_PyBytesWriter_WriteBytes() parameter.
For example, binascii uses "unsigned char*".
Optimize bytes.__mod__(args) for integere formats: %d (%i, %u), %o, %x and %X.
_PyBytesWriter is now used to format directly the integer into the writer
buffer, instead of using a temporary bytes object.
Formatting is between 30% and 50% faster on a microbenchmark.
string is pure ASCII: use _PyBytesWriter_WriteBytes(), don't check individual
character.
Cleanup unicode_encode_ucs1():
* Rename repunicode to rep
* Clear rep object on error
* Factorize code between bytes and unicode path
* Thanks to the _PyBytesWriter API, output smaller than 512 bytes are allocated
on the stack and so avoid calling _PyBytes_Resize(). Because of that, change
the default buffer size to fmtcnt instead of fmtcnt+100.
* Rely on _PyBytesWriter algorithm to overallocate the buffer instead of using
a custom code. For example, _PyBytesWriter uses a different overallocation
factor (25% or 50%) depending on the platform to get best performances.
* Disable overallocation for the last write.
* Replace C loops to fill characters with memset()
* Add also many comments to _PyBytes_Format()
* Remove unused FORMATBUFLEN constant
* Avoid the creation of a temporary bytes object when formatting a floating
point number (when no custom formatting option is used)
* Fix also reference leaks on error handling
* Use Py_MEMCPY() to copy bytes between two formatters (%)
Issue #25318: Optimize backslashreplace and xmlcharrefreplace error handlers in
UTF-8 encoder. Optimize also backslashreplace error handler for ASCII and
Latin1 encoders.
Use the new _PyBytesWriter API to optimize these error handlers for the
encoders. It avoids to create an exception and call the slow implementation of
the error handler.
Add a new private API to optimize Unicode encoders. It uses a small buffer
allocated on the stack and supports overallocation.
Use _PyBytesWriter API for UCS1 (ASCII and Latin1) and UTF-8 encoders. Enable
overallocation for the UTF-8 encoder with error handlers.
unicode_encode_ucs1(): initialize collend to collstart+1 to not check the
current character twice, we already know that it is not ASCII.
1. Non-ASCII bytes were accepted after shift sequence.
2. A low surrogate could be emitted in case of error in high surrogate.
3. In some circumstances the '\xfd' character was produced instead of the
replacement character '\ufffd' (due to a bug in _PyUnicodeWriter).
1. Non-ASCII bytes were accepted after shift sequence.
2. A low surrogate could be emitted in case of error in high surrogate.
3. In some circumstances the '\xfd' character was produced instead of the
replacement character '\ufffd' (due to a bug in _PyUnicodeWriter).
Issue #25227: Optimize ASCII and latin1 encoders with the ``surrogateescape``
error handler: the encoders are now up to 3 times as fast.
Initial patch written by Serhiy Storchaka.
* Change limit type from unsigned int to Py_UCS4, to use the same type than the
"ch" variable (an Unicode character).
* Reuse ch variable for _Py_ERROR_XMLCHARREFREPLACE
* Add some newlines for readability
ignore and replace. Initial patch written by Naoki Inada.
The decoder is now up to 60 times as fast for these error handlers.
Add also unit tests for the ASCII decoder.
* Call _Py_CheckFunctionResult() to check for bugs in type
constructors (tp_new)
* Add assertions to ensure an exception was raised if tp_init failed
or that no exception was raised if tp_init succeed
Refactor also the function to have less indentation.
with a single entry point, named exit points at the bottom, more self-evident
refcount adjustments, and a comment describing why the pre-increment was
necessary at all.
The real benefit of the unicode specialized function comes from
bypassing the overhead of PyObject_RichCompareBool() and not
from being in-lined (especially since there was almost no shared
data between the caller and callee). Also, the in-lining was
having a negative effect on code generation for the callee.
Simplifies the code a little bit and does the resize check
only when a new key is added (giving a small speed up in
the case where the key already exists).
Fixes possible bug in set_merge() where the set_insert_key()
call relies on a big resize at the start to make enough room
for the keys but is vulnerable to a comparision callback that
could cause the table to shrink in the middle of the merge.
Also, changed the resize threshold from two-thirds of the
mask+1 to just two-thirds. The plus one offset gave no
real benefit (afterall, the two-thirds mark is just a
heuristic and isn't a precise cut-off).
Summary of changes:
1. Coroutines now have a distinct, separate from generators
type at the C level: PyGen_Type, and a new typedef PyCoroObject.
PyCoroObject shares the initial segment of struct layout with
PyGenObject, making it possible to reuse existing generators
machinery. The new type is exposed as 'types.CoroutineType'.
As a consequence of having a new type, CO_GENERATOR flag is
no longer applied to coroutines.
2. Having a separate type for coroutines made it possible to add
an __await__ method to the type. Although it is not used by the
interpreter (see details on that below), it makes coroutines
naturally (without using __instancecheck__) conform to
collections.abc.Coroutine and collections.abc.Awaitable ABCs.
[The __instancecheck__ is still used for generator-based
coroutines, as we don't want to add __await__ for generators.]
3. Add new opcode: GET_YIELD_FROM_ITER. The opcode is needed to
allow passing native coroutines to the YIELD_FROM opcode.
Before this change, 'yield from o' expression was compiled to:
(o)
GET_ITER
LOAD_CONST
YIELD_FROM
Now, we use GET_YIELD_FROM_ITER instead of GET_ITER.
The reason for adding a new opcode is that GET_ITER is used
in some contexts (such as 'for .. in' loops) where passing
a coroutine object is invalid.
4. Add two new introspection functions to the inspec module:
getcoroutinestate(c) and getcoroutinelocals(c).
5. inspect.iscoroutine(o) is updated to test if 'o' is a native
coroutine object. Before this commit it used abc.Coroutine,
and it was requested to update inspect.isgenerator(o) to use
abc.Generator; it was decided, however, that inspect functions
should really be tailored for checking for native types.
6. sys.set_coroutine_wrapper(w) API is updated to work with only
native coroutines. Since types.coroutine decorator supports
any type of callables now, it would be confusing that it does
not work for all types of coroutines.
7. Exceptions logic in generators C implementation was updated
to raise clearer messages for coroutines:
Before: TypeError("generator raised StopIteration")
After: TypeError("coroutine raised StopIteration")
Martin Panter
Serhiy Storchaka
Victor Stinner
Benjamin Peterson
Guido van Rossum
Guido van Rossum
Eric V. Smith
Stefan Krah
Eric Snow
Raymond Hettinger
Zachary Ware
Yury Selivanov