An int of exactly 32 bits, regardless of the machine.
Side note: There's not much reason to want an int of at least 32 bits (i.e., 32 on 32-bit machines and 63 on 64-bit machines) because Int63
is basically just as efficient.
Overflow issues are not generally considered and explicitly handled. This may be more of an issue for 32-bit ints than 64-bit ints.
Int32.t
is boxed on both 32-bit and 64-bit machines.
include Sexplib0.Sexpable.S with type t := t
val t_sexp_grammar : t Sexplib0.Sexp_grammar.t
include Floatable.S with type t := t
val of_float : float -> t
val to_float : t -> float
include Intable.S with type t := t
val of_int_exn : int -> t
val to_int_exn : t -> int
include Identifiable.S with type t := t
include Sexplib0.Sexpable.S with type t := t
val t_of_sexp : Sexplib0__.Sexp.t -> t
val sexp_of_t : t -> Sexplib0__.Sexp.t
include Stringable.S with type t := t
val of_string : string -> t
val to_string : t -> string
include Comparable.S with type t := t
include Comparisons.S with type t := t
val equal : t -> t -> bool
val compare : t -> t -> int
compare t1 t2
returns 0 if t1
is equal to t2
, a negative integer if t1
is less than t2
, and a positive integer if t1
is greater than t2
.
val ascending : t -> t -> int
ascending
is identical to compare
. descending x y = ascending y x
. These are intended to be mnemonic when used like List.sort ~compare:ascending
and List.sort
~cmp:descending
, since they cause the list to be sorted in ascending or descending order, respectively.
val descending : t -> t -> int
val between : t -> low:t -> high:t -> bool
between t ~low ~high
means low <= t <= high
val clamp_exn : t -> min:t -> max:t -> t
clamp_exn t ~min ~max
returns t'
, the closest value to t
such that between t' ~low:min ~high:max
is true.
Raises if not (min <= max)
.
include Comparable.With_zero with type t := t
val is_positive : t -> bool
val is_non_negative : t -> bool
val is_negative : t -> bool
val is_non_positive : t -> bool
Returns Neg
, Zero
, or Pos
in a way consistent with the above functions.
val of_string_opt : string -> t option
val to_string_hum : ?delimiter:char -> t -> string
delimiter
is an underscore by default.
Infix operators and constants
Negation
There are two pairs of integer division and remainder functions, /%
and %
, and /
and rem
. They both satisfy the same equation relating the quotient and the remainder:
x = (x /% y) * y + (x % y);
x = (x / y) * y + (rem x y);
The functions return the same values if x
and y
are positive. They all raise if y = 0
.
The functions differ if x < 0
or y < 0
.
If y < 0
, then %
and /%
raise, whereas /
and rem
do not.
x % y
always returns a value between 0 and y - 1
, even when x < 0
. On the other hand, rem x y
returns a negative value if and only if x < 0
; that value satisfies abs (rem x y) <= abs y - 1
.
val (//) : t -> t -> float
Float division of integers.
val (lsl) : t -> int -> t
val (asr) : t -> int -> t
Other common functions
round
rounds an int to a multiple of a given to_multiple_of
argument, according to a direction dir
, with default dir
being `Nearest
. round
will raise if to_multiple_of <= 0
. If the result overflows (too far positive or too far negative), round
returns an incorrect result.
| `Down | rounds toward Int.neg_infinity |
| `Up | rounds toward Int.infinity |
| `Nearest | rounds to the nearest multiple, or `Up in case of a tie |
| `Zero | rounds toward zero |
Here are some examples for round ~to_multiple_of:10
for each direction:
| `Down | {10 .. 19} --> 10 | { 0 ... 9} --> 0 | {-10 ... -1} --> -10 |
| `Up | { 1 .. 10} --> 10 | {-9 ... 0} --> 0 | {-19 .. -10} --> -10 |
| `Zero | {10 .. 19} --> 10 | {-9 ... 9} --> 0 | {-19 .. -10} --> -10 |
| `Nearest | { 5 .. 14} --> 10 | {-5 ... 4} --> 0 | {-15 ... -6} --> -10 |
For convenience and performance, there are variants of round
with dir
hard-coded. If you are writing performance-critical code you should use these.
val round :
?dir:[ `Zero | `Nearest | `Up | `Down ] ->
t ->
to_multiple_of:t ->
t
val round_towards_zero : t -> to_multiple_of:t -> t
val round_down : t -> to_multiple_of:t -> t
val round_up : t -> to_multiple_of:t -> t
val round_nearest : t -> to_multiple_of:t -> t
Returns the absolute value of the argument. May be negative if the input is min_value
.
Successor and predecessor functions
Exponentiation
pow base exponent
returns base
raised to the power of exponent
. It is OK if base <= 0
. pow
raises if exponent < 0
, or an integer overflow would occur.
Bit-wise logical operations
val bit_and : t -> t -> t
These are identical to land
, lor
, etc. except they're not infix and have different names.
val bit_xor : t -> t -> t
Returns the number of 1 bits in the binary representation of the input.
Bit-shifting operations
The results are unspecified for negative shifts and shifts >= num_bits
.
val shift_left : t -> int -> t
Shifts left, filling in with zeroes.
val shift_right : t -> int -> t
Shifts right, preserving the sign of the input.
Increment and decrement functions for integer references
val decr : t Stdlib.ref -> unit
val incr : t Stdlib.ref -> unit
val of_int32_exn : int32 -> t
val to_int32_exn : t -> int32
val of_int64_exn : int64 -> t
val to_int64 : t -> int64
val of_nativeint_exn : nativeint -> t
val to_nativeint_exn : t -> nativeint
val of_float_unchecked : float -> t
of_float_unchecked
truncates the given floating point number to an integer, rounding towards zero. The result is unspecified if the argument is nan or falls outside the range of representable integers.
The number of bits available in this integer type. Note that the integer representations are signed.
The largest representable integer.
The smallest representable integer.
val (lsr) : t -> int -> t
Same as shift_right_logical
.
val shift_right_logical : t -> int -> t
Shifts right, filling in with zeroes, which will not preserve the sign of the input.
ceil_pow2 x
returns the smallest power of 2 that is greater than or equal to x
. The implementation may only be called for x > 0
. Example: ceil_pow2 17 = 32
floor_pow2 x
returns the largest power of 2 that is less than or equal to x
. The implementation may only be called for x > 0
. Example: floor_pow2 17 = 16
ceil_log2 x
returns the ceiling of log-base-2 of x
, and raises if x <= 0
.
val floor_log2 : t -> int
floor_log2 x
returns the floor of log-base-2 of x
, and raises if x <= 0
.
is_pow2 x
returns true iff x
is a power of 2. is_pow2
raises if x <= 0
.
Returns the number of leading zeros in the binary representation of the input, as an integer between 0 and one less than num_bits
.
The results are unspecified for t = 0
.
Returns the number of trailing zeros in the binary representation of the input, as an integer between 0 and one less than num_bits
.
The results are unspecified for t = 0
.
A sub-module designed to be opened to make working with ints more convenient.
Conversion functions
val of_int : int -> t option
val to_int : t -> int option
val of_int32 : int32 -> t
val to_int32 : t -> int32
val of_nativeint : nativeint -> t option
val to_nativeint : t -> nativeint
val of_int64 : int64 -> t option
Truncating conversions
These functions return the least-significant bits of the input. In cases where optional conversions return Some x
, truncating conversions return x
.
val of_int_trunc : int -> t
val to_int_trunc : t -> int
val of_nativeint_trunc : nativeint -> t
val of_int64_trunc : int64 -> t
Low-level float conversions
val bits_of_float : float -> t
Rounds a regular 64-bit OCaml float to a 32-bit IEEE-754 "single" float, and returns its bit representation. We make no promises about the exact rounding behavior, or what happens in case of over- or underflow.
val float_of_bits : t -> float
Creates a 32-bit IEEE-754 "single" float from the given bits, and converts it to a regular 64-bit OCaml float.
Byte swap operations
See Int
's byte swap section for a description of Base's approach to exposing byte swap primitives.
When compiling for 64-bit machines, if signedness of the output value does not matter, use byteswap functions for int64
, if possible, for better performance. As of writing, 32-bit byte swap operations on 64-bit machines have extra overhead for moving to 32-bit registers and sign-extending values when returning to 64-bit registers.
The x86 instruction sequence that demonstrates the overhead is in base/bench/bench_int.ml