View Source Wafer.Twiddles (wafer v1.1.0)

Handy functions for dealing with bits and bytes in the wild.

Summary

Types

bit()
bit_number()
single_byte_binary()

Functions

clear_bit(byte, bit_number)

Set the specified bit to 0 within the byte.

count_ones(byte)

Returns the number of 1's in byte.

count_zeroes(byte)

Returns the number of 0's in byte.

find_ones(byte)

Find all the 1 bits in byte and return a list of bit_numbers.

find_zeroes(byte)

Find all the 0 bits in byte and return a list of bit_numbers.

get_bit(byte, bit_number)

Get the bit at the specified bit_number within byte.

get_bool(byte, bit_number)

Return a bit out of a binary as a boolean value.

is_bit(bit)
is_bit_number(bit)
is_byte(byte)
set_bit(byte, bit_number)

Set a the specified bit_number to 1 within the byte.

set_bit(byte, bit_number, value)

Set the bit at the specified bit_number within the byte to the bit value.

Types

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bit()

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@type bit() :: 0..1
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bit_number()

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@type bit_number() :: 0..7
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single_byte_binary()

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@type single_byte_binary() :: <<_::8>>

Functions

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clear_bit(byte, bit_number)

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@spec clear_bit(byte() | single_byte_binary(), bit_number()) :: byte()

Set the specified bit to 0 within the byte.

Example 

iex> clear_bit(3, 0)
2

iex> clear_bit(<<3>>, 0)
<<2>>
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count_ones(byte)

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@spec count_ones(byte() | single_byte_binary()) :: non_neg_integer()

Returns the number of 1's in byte.

Example 

iex> count_ones(0x7f)
7

iex> count_ones(<<0x7F>>)
7
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count_zeroes(byte)

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@spec count_zeroes(byte() | single_byte_binary()) :: non_neg_integer()

Returns the number of 0's in byte.

Example 

iex> count_zeroes(0x7f)
1

iex> count_zeroes(<<0x7F>>)
1
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find_ones(byte)

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@spec find_ones(byte() | single_byte_binary()) :: [non_neg_integer()]

Find all the 1 bits in byte and return a list of bit_numbers.

Example 

iex> find_ones(0x0A)
[1, 3]

iex> find_ones(<<0x0A>>)
[1, 3]
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find_zeroes(byte)

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@spec find_zeroes(byte() | single_byte_binary()) :: [non_neg_integer()]

Find all the 0 bits in byte and return a list of bit_numbers.

Example 

iex> find_zeroes(0xFA)
[0, 2]

iex> find_zeroes(<<0xFA>>)
[0, 2]
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get_bit(byte, bit_number)

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@spec get_bit(byte() | single_byte_binary(), bit_number()) :: bit()

Get the bit at the specified bit_number within byte.

Example 

iex> get_bit(0x7f, 6)
1

iex> get_bit(<<0x7F>>, 6)
1
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get_bool(byte, bit_number)

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@spec get_bool(byte() | single_byte_binary(), bit_number()) :: boolean()

Return a bit out of a binary as a boolean value.

Example 

iex> get_bool(0x7f, 6)
true

iex> get_bool(<<0x7F>>, 6)
true
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is_bit(bit)

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is_bit_number(bit)

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is_byte(byte)

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set_bit(byte, bit_number)

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@spec set_bit(byte() | single_byte_binary(), bit_number()) :: byte()

Set a the specified bit_number to 1 within the byte.

Example 

iex> set_bit(0, 0)
1

iex> set_bit(<<0>>, 0)
<<1>>
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set_bit(byte, bit_number, value)

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@spec set_bit(byte() | single_byte_binary(), bit_number(), bit()) :: byte()

Set the bit at the specified bit_number within the byte to the bit value.

Example 

iex> set_bit(0, 1, 1)
2

iex> set_bit(<<0>>, 1, 1)
<<2>>

iex> set_bit(0, 1, true)
2

iex> set_bit(<<0>>, 1, true)
<<2>>