Rewrite the code to handle the output buffer.

Fix usage of _PyBytesWriter API. Use the new _PyBytesWriter_Resize() function
instead of _PyBytesWriter_Prepare().

This function gives a control to the buffer size without using min_size.

* 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

enhance code to detect buffer under- and overflow.

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.

Issue #25399: Add a new use_bytearray attribute to _PyBytesWriter to use a
bytearray buffer, instead of using a bytes object.

Issue #25399: Fix long_format_binary(), allocate bytes for the bytes writer.

tab in the IDLE Preferences dialog.  Code patch by Mark Roseman.

On Windows, sprintf("%p", 0xabcdef) formats hexadecimal in uppercase and pad to
16 characters (on 64-bit system) with zeros.

* 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

MEMOIZE opcode.

pickletools.opcodes.

pickletools.opcodes.

pickletools.opcodes.

This API avoids a final call to _PyBytes_Resize() for output smaller than 512
bytes.

Small optimization: disable overallocation in binascii.rledecode_hqx() for the
last write.

Patch by Serhiy Storchaka.

Issue #25274: sys.setrecursionlimit() now raises a RecursionError if the new
recursion limit is too low depending at the current recursion depth. Modify
also the "lower-water mark" formula to make it monotonic. This mark is used to
decide when the overflowed flag of the thread state is reset.

condition in test_eintr.

the new _PyBytesWriter API.

Ignore pickle.partial symbol which comes from functools.partial.

Modify _PyBytesWriter_Finish() and _PyUnicodeWriter_Finish() to return the
empty bytes/Unicode string if the string is empty.