Files
ruby/doc/string/bit_set_p.rdoc
HASUMI Hitoshi 2461caebba [Feature #22118] Introduce Basic Bit Operations into String (#17353)
This patch adds the following methods to String class:

* String#bit_get(offset, lsb_first: true) -> 1 | 0 | nil
* String#bit_set?(offset, lsb_first: true) -> true | false | nil
* String#bit_set(offset, lsb_first: true) -> self
* String#bit_clear(offset, lsb_first: true) -> self
* String#bit_flip(offset, lsb_first: true) -> self
* String#bit_count -> Integer
* String#bitwise_not -> String
* String#bitwise_not! -> self
* String#bitwise_and(other) -> String
* String#bitwise_and!(other) -> self
* String#bitwise_or(other) -> String
* String#bitwise_or!(other) -> self
* String#bitwise_xor(other) -> String
* String#bitwise_xor!(other) -> self

Other than implementation, tests, specs, and docs are added.

Link: [Feature #22118]

## Note

In `string.c`, I wrote some big macro that create method functions and helper
functions:

* STR_DEFINE_BINARY_BITWISE_METHOD
* STR_DEFINE_UNARY_BITWISE_KERNEL
* STR_DEFINE_BINARY_BITWISE_KERNEL

While using macros like this reduces maintainability, I believe it's acceptable
because there are no plans to extend the `bitwise_*` methods beyond this
proposal, and the logic is stable.

On the other hand, other methods such as `bit_get` and `bit_count` are planned to
have argument extensions in the future.
2026-08-06 21:40:37 +09:00

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Returns +true+ or +false+ for whether the bit at zero-based bit +offset+ is set:
s = "\xAA" # 0b10101010
s.bit_set?(0) # => false
s.bit_set?(1) # => true
Returns +nil+ if +offset+ is beyond the end of +self+:
s.bit_set?(8) # => nil
By default, bits within each byte are numbered from least-significant to
most-significant. If +lsb_first+ is +false+, byte order is unchanged but bits
within each byte are numbered from most-significant to least-significant:
s.bit_set?(0, lsb_first: false) # => true
s.bit_set?(1, lsb_first: false) # => false
Raises +IndexError+ if +offset+ is negative.
Raises +ArgumentError+ if +offset+ is too large to be represented.
Raises +ArgumentError+ if +lsb_first+ is neither +true+ nor +false+.