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utils Module

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Classes

CountUpDownLatch

CountUpDownLatch provides a thread safe implementation of Up Down latch

Functions

clamp

Limit a value to a given range

This is equivalent to smallest <= n <= largest.

clamp(n, smallest, largest)

Parameters

n
smallest
largest

Examples


>>> clamp(0, 1, 100)
1


>>> clamp(42, 2, 128)
42


>>> clamp(1024, 1, 32)
32

commonprefix

Find common directory for all paths

Python's os.path.commonprefix will not return a valid directory path in some cases, so we wrote this convenience method.

commonprefix(paths)

Parameters

paths

Examples


>>> # os.path.commonprefix returns '/disk1/foo'
>>> commonprefix(['/disk1/foobar', '/disk1/foobaz'])
'/disk1'


>>> commonprefix(['a/b/c', 'a/b/d', 'a/c/d'])
'a'


>>> commonprefix(['a/b/c', 'd/e/f', 'g/h/i'])
''

ensure_writable 

ensure_writable(b)

Parameters

b

read_block

Read a block of bytes from a file

read_block(f, offset, length, delimiter=None)

Parameters

fn
<xref:<xref:file object>>
Required

a file object that supports seek, tell and read.

offset
int
Required

Byte offset to start read

length
int
Required

Maximum number of bytes to read

delimiter
bytes(<xref:optional>)
default value: None

Ensure reading stops at delimiter bytestring

using the delimiter= keyword argument we ensure that the read
<xref:If>
Required
at or before the delimiter boundaries that follow the location
<xref:stops>
Required
+ length. For ADL
<xref:offset>
Required
no delimiter is found and the data
<xref:if>
Required
is > 4MB an exception is raised
<xref:requested>
Required
a single record cannot
<xref:since>
Required
4MB and be guaranteed to land contiguously in ADL.
<xref:exceed>
Required
bytestring returned WILL include the
<xref:The>
Required
delimiter string.
<xref:terminating>
Required

Examples


>>> from io import BytesIO  
>>> f = BytesIO(b'Alice, 100\nBob, 200\nCharlie, 300')  
>>> read_block(f, 0, 13)  
b'Alice, 100\nBo'


>>> read_block(f, 0, 13, delimiter=b'\n')  
b'Alice, 100\n'


>>> read_block(f, 10, 10, delimiter=b'\n')  
b'\nCharlie, 300'
>>> f  = BytesIO(bytearray(2**22))  
>>> read_block(f,0,2**22, delimiter=b'\n')  
IndexError: No delimiter found within max record size of 4MB.
Transfer without specifying a delimiter (as binary) instead.

tokenize

Deterministic token


>>> tokenize('Hello') == tokenize('Hello')
True

tokenize(*args, **kwargs)

write_stdout

Write bytes or strings to standard output

write_stdout(data)

Parameters

data