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Simple implementation of circular buffer

Project description

  • License : MIT

Summary

Simple circular buffer written in python extension.

CircularBuffer will allocate requested size + 2 bytes for two sections of null terminated strings.

May temporary allocate another half of the allocated bytes if you used buffer protocol, I mostly used them for regex.

Installation

Simply pip install pycircularbuffer, compilation from downloaded source is probably needed.

Using

from circularbuffer import CircularBuffer

buf = CircularBuffer(1024)

buf.write(b'some text')
while len(buf) > 0:
    buf.read(1)

from re import match

buf.write(b'hallo')

# python2
with buf:
    match_found = match(br'^ha', buf)

# python3
match_found = match(br'^ha', buf)

# use `result` immediately because regex didn't make memory copy of the
# internal buffer, or run another `match()` on a memory copy, for example:

match_found_str = buf.read(len(match_found.group(0)))
independent_match_found = match(br'^ha', match_found_str)

Warning

Don’t to this in python 3: ‘a’ in buf, instead: b’a’ in buf.

Check the return value of write() which is the actual length that was written into the buffer and also the exception that might be raised.

API

Regular methods:

  • clear()
  • read()
  • resize()
  • write()
  • write_available()
  • make_contiguous()

String methods:

  • count()
  • startswith()
  • find()
  • index()

Sequence methods:

  • __contains__()
  • __getitem__()
  • __len__()
  • __setitem__()

Magic methods:

  • __repr__()

  • __str__()

    Note: while string representation makes thing easier it always creates memory copy.

  • __enter__()

  • __exit__()

Buffer protocol:

Note: for python version < 3, you need to use context manager, the with statement, to let CircularBuffer know when you are releasing the buffer.

Using buffer protocol will throw ReservedError exception for CircularBuffer.read().

Project details


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Source Distribution

pycircularbuffer-0.0.9.tar.gz (11.4 kB view hashes)

Uploaded source

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