np-rw-buffer 1.2.0

This library was created to help store audio data in a numpy array. It allows for writing lists and numpy arrays into a circular buffer. You can read the data from the buffer with overlap to perform smooth FFTs. The buffer is a wrapper around a numpy ndarray. It contains a start and end position to keep track of where to read and write the data.

Main Functions:

• clear() - Clear the length, start, and end indexes

• get_data() - Return a copy of the data without moving indexes

• set_data(data) - Set the data and change the shape of the buffer to this data shape

• write(data, error) - Write data into the buffer and move the end index

• read(amount) - Read data from the buffer and move the start index. If the amount is greater that what is in the buffer return a 0 length buffer

Extra Functions to help with the start and end pointers:

• expanding_write(data, error) - Write data into the buffer. If the data is larger than the buffer expand the buffer

• growing_write(data) - Write data into the buffer if there is not enough space make the buffer larger

• write_value(value, length, error=True, move_start=True) - Write a value into the buffer for the given length. This is more efficient then creating and writing an array of a single value.

• write_zeros(length, error=True, move_start=True) - Write Zeros for the given length. This is more efficient then creating and writing an array of zeros.

• read_remaining(amount) - Read the amount or read all of the data available to read

• read_overlap(amount, increment) - Read the amount of data given, but only increment the start index by the increment amount. This makes the next read, read some duplicate data (hence overlap)

Buffer Control Functions:

• maxsize - (property) change the amount of samples that can be held

• columns - (property) Number of columns that the array contains (shape[1])

• shape - (property) Change the shape of the buffer

• dtype - (property) Change the data type for the numpy buffer

• get_indexes(start, length) - Return a list of indexes for reading and writing (this makes the buffer circular)

• move_start(amount, error) - Move the start index (read)

• move_end(amount, error) - Move the end index (write)

• get_available_space() - return the amount of data that the buffer can still hold

import numpy as np
import np_rw_buffer

buffer = np_rw_buffer.RingBuffer(10)

buffer.write(np.arange(5))
r = buffer.read(4)
assert np.all(r == np.arange(4).reshape((-1, 1)))

# Not enough data, don't read anything (use read_remaining or get_data)
d = np.arange(5).reshape((-1, 1))
buffer.write(d)
r = buffer.read(10)
assert len(r) == 0
assert len(buffer) == 6

r = buffer.read()
assert len(r) == 6
assert np.all(r == np.vstack((d[-1:], d)))

buffer.write(np.arange(6))
# buffer.write(np.arange(5))  # Raises an OverflowError
buffer.write(np.arange(5), False)

import numpy as np
from np_rw_buffer import AudioFramingBuffer

buffer = AudioFramingBuffer(2000, 1)
buffer.write(np.array([(i,) for i in range(10)]))
# Buffer: [(read ptr)0, 1, 2, 3, 4, 5, 6, 7, 8, 9, (write ptr) 0, 0, 0, 0, 0]
assert buffer._end == 10
assert buffer._start == 0

# [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, (write ptr) 0, 0, 0, 0, 0] (read ptr at end)
assert np.all(buffer.read(15) == np.array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0, 0, 0, 0]).reshape((-1, 1)))
assert buffer._start == 15
assert buffer._end == 10

buffer.write(np.array([(i,) for i in range(10)])) # This will write in the position after 19
# Buffer: [0, 0, 0, 0, 0, 0, 0, 0, 0, (was 9) 0, 0, 1, 2, 3, 4, (read ptr) 5, 6, 7, 8, 9] (write ptr at end)
assert buffer._end == 20
assert buffer._start == 15

# [5, 6, 7, 8, 9, (write ptr) 0, 0, 0, 0, 0] (read ptr at end)
assert np.all(buffer.read(10) == np.array([5, 6, 7, 8, 9, 0, 0, 0, 0, 0]).reshape((-1, 1)))