Bitwise operations are operations that manipulate individual bits in binary representations of numbers. These operations work at the binary level,
treating numbers as sequences of 32 bits (in 32-bit environments) or 64 bits (in 64-bit environments). However, they should not be used in a boolean
context because they have different behaviors compared to logical operators when applied to boolean values:
- When applied to boolean values, bitwise AND (
&) and OR (|) perform bitwise operations on the binary
representation of the numbers. They treat the operands as 32-bit signed integers and manipulate their individual bits.
- Logical AND (
&&) and OR (||) are specifically designed for boolean operations. They return a boolean value
based on the truthiness or falsiness of the operands.&& returns true if both operands are truthy; otherwise, it
returns false. || operator returns true if at least one of the operands is truthy; otherwise, it returns
false.
Bitwise operators & and | can be easily mistaken for logical operators && and ||,
especially for those who are not familiar with the distinction between them or their specific use cases.
This rule raises an issue when & or | is used in a boolean context.
if (a & b) { /* ... */ } // Noncompliant: The operator & is used in a boolean context
You should use the logical variant of the bitwise operator, that is, && instead of & and ||
instead of |.
if (a && b) { /* ... */ }
Exceptions
When a file contains other bitwise operations, (^, <<, >>>, >>,
~, &=, ^=, |=, <<=, >>=, >>>=, and
& or | used with a numeric literal as the right operand) all issues in the file are ignored, because it is evidence that
bitwise operations were truly intended.
