Bitmaskar

Bitmaskar, or bitmasks, are patterns of bits used to select or modify specific bits within a binary value. They are a fundamental tool in low-level programming, enabling efficient manipulation of flags, fields, and small integers.

A mask expresses which bit positions should be affected via bitwise operations. Common operators are AND, OR, XOR, and NOT. Testing a bit is usually done with value & mask; if the result is nonzero, the bit is set. Setting a bit uses value |= mask; clearing uses value &= ~mask; toggling uses value ^= mask. Often masks are created by shifting a 1 into the desired position (for example, 1 << n).

Bitmasks can be single-bit masks (one bit set) or multi-bit masks that cover several adjacent bits. They are frequently written in hexadecimal for readability and used to extract or modify bitfields in packed data, hardware registers, file permissions, and protocol headers.

Common applications include representing feature flags, permission sets, status registers, and compact network or file metadata. Mask design should consider integer width (8, 16, 32, or 64-bit) and language specifics, such as signedness and operator behavior. In languages with arbitrary-precision integers, masks can be of any size but still rely on the same principles.