bitwise (ex_stdlib v0.2.0)
View SourceBitwise operations module inspired by Elixir's Bitwise module.
This module provides a set of functions for performing bitwise operations on integers. All functions work only on integers, otherwise a badarg error is raised.
Examples:
% Bitwise AND
1 = bitwise:bit_and(9, 3),
% Bitwise OR
11 = bitwise:bit_or(9, 3),
% Bitwise XOR
10 = bitwise:bit_xor(9, 3),
% Bitwise NOT
-3 = bitwise:bit_not(2),
% Left shift
4 = bitwise:bit_shift_left(1, 2),
% Right shift
0 = bitwise:bit_shift_right(1, 2).Summary
Functions
Calculates the bitwise AND of its arguments.
Calculates the bitwise NOT of the argument.
Calculates the bitwise OR of its arguments.
Calculates the result of an arithmetic left bitshift.
Calculates the result of an arithmetic right bitshift.
Calculates the bitwise XOR of its arguments.
Clears a specific bit to 0 in an integer.
Counts the number of leading zero bits in an integer.
Counts the number of set bits (1s) in an integer.
Counts the number of trailing zero bits in an integer.
Counts the number of zero bits in the lower bits of an integer.
Rotates bits to the left by a specified number of positions.
Rotates bits to the right by a specified number of positions.
Sets a specific bit to 1 in an integer.
Tests if a specific bit is set in an integer.
Toggles a specific bit in an integer.
Types
-type integer_type() :: integer().
Functions
Calculates the bitwise AND of its arguments.
Equivalent to Erlang's band/2. Returns a new integer with bits set only where both arguments have the corresponding bit set.
Examples:
1 = bitwise:bit_and(9, 3), % 1001 & 0011 = 0001
0 = bitwise:bit_and(5, 2). % 0101 & 0010 = 0000Calculates the bitwise NOT of the argument.
Equivalent to Erlang's bnot/1. The result is the bitwise complement of the input integer.
Examples:
-3 = bitwise:bit_not(2),
1 = bitwise:bit_and(bitwise:bit_not(2), 3).Calculates the bitwise OR of its arguments.
Equivalent to Erlang's bor/2. Returns a new integer with bits set where either argument has the corresponding bit set.
Examples:
11 = bitwise:bit_or(9, 3), % 1001 | 0011 = 1011
7 = bitwise:bit_or(5, 2). % 0101 | 0010 = 0111Calculates the result of an arithmetic left bitshift.
Equivalent to Erlang's bsl/2. Shifts the bits of the first argument to the left by the number of positions specified by the second argument. A negative shift amount results in a right shift.
Examples:
4 = bitwise:bit_shift_left(1, 2), % 0001 << 2 = 0100
0 = bitwise:bit_shift_left(1, -2), % 0001 >> 2 = 0000
-4 = bitwise:bit_shift_left(-1, 2), % Arithmetic shift preserves sign
-1 = bitwise:bit_shift_left(-1, -2).Calculates the result of an arithmetic right bitshift.
Equivalent to Erlang's bsr/2. Shifts the bits of the first argument to the right by the number of positions specified by the second argument. A negative shift amount results in a left shift.
Examples:
0 = bitwise:bit_shift_right(1, 2), % 0001 >> 2 = 0000
4 = bitwise:bit_shift_right(1, -2), % 0001 << 2 = 0100
-1 = bitwise:bit_shift_right(-1, 2), % Arithmetic shift preserves sign
-4 = bitwise:bit_shift_right(-1, -2).Calculates the bitwise XOR of its arguments.
Equivalent to Erlang's bxor/2. Returns a new integer with bits set where exactly one of the arguments has the corresponding bit set.
Examples:
10 = bitwise:bit_xor(9, 3), % 1001 ^ 0011 = 1010
7 = bitwise:bit_xor(5, 2). % 0101 ^ 0010 = 0111-spec clear_bit(integer(), non_neg_integer()) -> integer().
Clears a specific bit to 0 in an integer.
Sets the bit at the specified position (0-indexed from the right) to 0. Position 0 is the least significant bit.
Examples:
8 = bitwise:clear_bit(9, 0), % 1001 -> 1000
8 = bitwise:clear_bit(12, 2), % 1100 -> 1000
8 = bitwise:clear_bit(8, 0). % 1000 -> 1000 (already clear)-spec count_leading_zeros(integer()) -> non_neg_integer().
Counts the number of leading zero bits in an integer.
Counts the number of consecutive zero bits from the most significant bit. For zero, returns the word size (32 bits).
Examples:
28 = bitwise:count_leading_zeros(15), % 0000...01111 has 28 leading zeros
31 = bitwise:count_leading_zeros(1), % 0000...00001 has 31 leading zeros
32 = bitwise:count_leading_zeros(0). % all zeros-spec count_ones(integer()) -> non_neg_integer().
Counts the number of set bits (1s) in an integer.
Uses a population count algorithm to efficiently count the number of 1 bits in the binary representation of the integer.
Examples:
2 = bitwise:count_ones(3), % 0011 has 2 ones
4 = bitwise:count_ones(15), % 1111 has 4 ones
0 = bitwise:count_ones(0). % 0000 has 0 ones-spec count_trailing_zeros(integer()) -> non_neg_integer().
Counts the number of trailing zero bits in an integer.
Counts the number of consecutive zero bits from the least significant bit. For zero, returns the word size (32 bits).
Examples:
2 = bitwise:count_trailing_zeros(12), % 1100 has 2 trailing zeros
0 = bitwise:count_trailing_zeros(15), % 1111 has 0 trailing zeros
32 = bitwise:count_trailing_zeros(0). % all zeros-spec count_zeros(integer()) -> non_neg_integer().
Counts the number of zero bits in the lower bits of an integer.
For positive integers, counts zeros in the binary representation. The exact behavior for negative numbers depends on the word size.
Examples:
2 = bitwise:count_zeros(12), % 1100 has 2 trailing zeros
0 = bitwise:count_zeros(15), % 1111 has 0 zeros-spec rotate_left(integer(), non_neg_integer()) -> integer().
Rotates bits to the left by a specified number of positions.
Performs a circular left shift within a 32-bit word. Bits that are shifted out from the left are rotated back in from the right.
Examples:
24 = bitwise:rotate_left(3, 3), % 0011 rotated left 3 -> 11000 (24)
6 = bitwise:rotate_left(3, 1). % 0011 rotated left 1 -> 0110 (6)-spec rotate_right(integer(), non_neg_integer()) -> integer().
Rotates bits to the right by a specified number of positions.
Performs a circular right shift within a 32-bit word. Bits that are shifted out from the right are rotated back in from the left.
Examples:
6 = bitwise:rotate_right(12, 1), % 1100 rotated right 1 -> 0110 (6)
3 = bitwise:rotate_right(12, 2). % 1100 rotated right 2 -> 0011 (3)-spec set_bit(integer(), non_neg_integer()) -> integer().
Sets a specific bit to 1 in an integer.
Sets the bit at the specified position (0-indexed from the right) to 1. Position 0 is the least significant bit.
Examples:
9 = bitwise:set_bit(8, 0), % 1000 -> 1001
12 = bitwise:set_bit(8, 2), % 1000 -> 1100
8 = bitwise:set_bit(8, 3). % 1000 -> 1000 (already set)-spec test_bit(integer(), non_neg_integer()) -> boolean().
Tests if a specific bit is set in an integer.
Returns true if the bit at the specified position (0-indexed from the right) is set to 1, false otherwise. Position 0 is the least significant bit.
Examples:
false = bitwise:test_bit(8, 0), % 1000 bit 0 is 0
true = bitwise:test_bit(9, 0), % 1001 bit 0 is 1
true = bitwise:test_bit(8, 3). % 1000 bit 3 is 1-spec toggle_bit(integer(), non_neg_integer()) -> integer().
Toggles a specific bit in an integer.
Flips the bit at the specified position (0-indexed from the right). Position 0 is the least significant bit.
Examples:
9 = bitwise:toggle_bit(8, 0), % 1000 -> 1001
8 = bitwise:toggle_bit(12, 2), % 1100 -> 1000
0 = bitwise:toggle_bit(8, 3). % 1000 -> 0000