Skip to main content

BITOP

Performs bitwise operations between multiple bitmaps and stores the result in a destination key.

Syntax​

BITOP operation destkey key [key ...]

Parameters​

  • operation: The bitwise operation to perform. Options are:
    • AND: Bitwise AND
    • OR: Bitwise OR
    • XOR: Bitwise XOR
    • NOT: Bitwise NOT (unary operation)
  • destkey: The key where the result of the bitwise operation will be stored.
  • key: One or more keys to perform the bitwise operation on. These are the source bitmaps.

Details​

  • Available since: 2.6.0
  • Time complexity: O(N) where N is the size of the bitmaps.
  • ACL categories: @write, @bitmap, @slow

The BITOP command performs bitwise operations on one or more bitmaps and stores the result in a new key. It supports several bitwise operations including AND, OR, XOR, and NOT. The command operates on byte-level granularity and the result will be of the same length as the longest input bitmap.

Operation Types​

  • AND: Performs a bitwise AND between all input bitmaps and stores the result in destkey.
  • OR: Performs a bitwise OR between all input bitmaps and stores the result in destkey.
  • XOR: Performs a bitwise XOR between all input bitmaps and stores the result in destkey.
  • NOT: Performs a bitwise NOT on a single input bitmap and stores the result in destkey.

Examples​

Bitwise AND Operation​

Assume we have the following keys with bitmap values:

SETBIT mykey1 0 1
SETBIT mykey1 1 1
SETBIT mykey2 0 1
SETBIT mykey2 1 0

To perform a bitwise AND operation between mykey1 and mykey2 and store the result in resultkey:

BITOP AND resultkey mykey1 mykey2

The value of resultkey will be 01, as the bitwise AND operation results in 01.

Bitwise OR Operation​

To perform a bitwise OR operation between mykey1 and mykey2:

BITOP OR resultkey mykey1 mykey2

The value of resultkey will be 11, as the bitwise OR operation results in 11.

Bitwise XOR Operation​

To perform a bitwise XOR operation between mykey1 and mykey2:

BITOP XOR resultkey mykey1 mykey2

The value of resultkey will be 11, as the bitwise XOR operation results in 11.

Bitwise NOT Operation​

To perform a bitwise NOT operation on mykey1:

BITOP NOT resultkey mykey1

The result will be the bitwise NOT of mykey1. If mykey1 had a value of 01, the result will be the complement, which depends on the bit-width (e.g., 10 for an 8-bit width).

Edge Cases​

  • If destkey already exists, it will be overwritten with the result.
  • If key does not exist, it is treated as an empty bitmap.
  • If NOT operation is used, only a single key should be specified.

RESP2/RESP3 Reply​

  • Integer reply: the length of the resulting bitmap in bytes.