API Reference

class zero_buffer.Buffer

A buffer is a fixed-size, append only, contigious region of memory. Once data is in it, that data cannot be mutated, however data can be read into the buffer with multiple calls.

classmethod allocate(size)
Parameters:size (int) – Number of bytes.
Return Buffer:The new buffer.

Allocates a new buffer of size bytes.

capacity

Returns the size of the underlying buffer. This is the same as what it was allocated with.

writepos

Returns the current, internal writing position, this increases on calls to read_from() and add_bytes().

free

Returns the remaining space in the Buffer.

read_from(fd)
Parameters:

fd (int) – A file descriptor.
Return int:

Number of bytes read.
Raises:
  • OSError – on an error reading from the file descriptor.
  • EOFError – when the read position of the file is at the end.
  • BufferFull – when the buffer has no remaining space when called

Reads from the file descriptor into the Buffer. Note that the number of bytes copied may be less than the number of bytes in the file.

add_bytes(b)
Parameters:b (bytes) – Bytes to copy into the buffer.
Return int:Number of bytes copied into the buffer.
Raises:BufferFull – when the buffer has no remaining space when called

Copies the bytes into the Buffer. Note that the number of bytes copied may be less than len(b) if there isn’t space in the Buffer.

view(start=0, stop=None)
Parameters:
  • start (int) – The byte-offset from the beggining of the buffer.
  • stop (int) – The byte-offset from start.
Return BufferView:
 
Raises:

ValueError – If the stop is before the start, if the start is negative or after the writepos, or if the stop is after the writepos.

Returns a view of the buffer’s data. This does not perform any copying.

class zero_buffer.BufferView

A buffer view is an immutable, fixed-size, view over a contigious region of memory. It exposes much of the same API as bytes, except most methods return BufferViews and do not make copies of the data. A buffer view is either a view into a Buffer or into another BufferView.

__bytes__()

Returns a copy of the contents of the view as a bytes.

__len__()

Returns the length of the view.

__eq__(other)

Checks whether the contents of the view are equal to other, which can be either a bytes or a BufferView.

__contains__(needle)

Returns whether or not the needle exists in the view as a contigious series of bytes.

__getitem__(idx)

If idx is a slice, returns a BufferView over that data, it does not perform a copy. If idx is an integer, it returns the ordinal value of the byte at that index.

Unlike other containers in Python, this does not support slices with steps (view[::2]).

__add__(other)
Parameters:other (BufferView) –

Returns a BufferView over the concatenated contents. If other is contigious with self in memory, no copying is performed, otherwise both views are copied into a new one.

find(needle, start=0, stop=None)

The same as bytes.find().

index(needle, start=0, stop=None)

The same as bytes.index().

rfind(needle, start=0, stop=None)

The same as bytes.rfind().

rindex(needle, start=0, stop=None)

The same as bytes.rindex().

split(by, maxsplit=-1)

Similar to bytes.split(), except it returns an iterator (not a list) over the results, and each result is a BufferView (not a bytes).

splitlines(keepends=False)

Similar to bytes.splitlines(), except it returns an iterator (not a list) over the results, and each result is a BufferView (not a bytes).

isspace()

The same as bytes.isspace().

isdigit()

The same as bytes.isdigit().

isalpha()

The same as bytes.isalpha().

strip(chars=None)

The same as bytes.strip() except it returns a BufferView (and not a bytes).

lstrip(chars=None)

The same as bytes.lstrip() except it returns a BufferView (and not a bytes).

rstrip(chars=None)

The same as bytes.rstrip() except it returns a BufferView (and not a bytes).

write_to(fd)
Parameters:fd (int) – A file descriptor.
Return int:Number of bytes written.
Raises:OSError – on an error writing to the file descriptor.

Writes the contents of the buffer to a file descriptor. Note that the number of bytes written may be less than the number of bytes in the buffer view.

class zero_buffer.BufferCollator

A buffer collator is a collection of BufferView objects which can be collapsed into a single BufferView.

__len__()

Returns the sum of the lengths of the views inside the collator.

append(view)
Parameters:view (BufferView) –

Adds the contents of a view to the collator.

collapse()

Collapses the contents of the collator into a single BufferView. Also resets the internal state of the collator, so if you call it twice successively, the second call will return an empty BufferView.