Base.Int64
Source64-bit integers.
include Sexplib0.Sexpable.S with type t := t
include Identifiable.S with type t := t
include Comparable.S with type t := t
include Comparisons.S with type t := t
include Comparisons.Infix with type t := t
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
.
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.
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 Pretty_printer.S with type t := t
include Invariant.S with type t := t
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
.
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.
These are identical to land
, lor
, etc. except they're not infix and have different names.
The results are unspecified for negative shifts and shifts >= num_bits
.
The number of bits available in this integer type. Note that the integer representations are signed.
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
.
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
.
include module type of O
These functions return the least-significant bits of the input. In cases where optional conversions return Some x
, truncating conversions return x
.
bits_of_float
will always allocate its result on the heap unless the _unboxed
C function call is chosen by the compiler.
float_of_bits
will always allocate its result on the heap unless the _unboxed
C function call is chosen by the compiler.
See Int
's byte swap section for a description of Base's approach to exposing byte swap primitives.
As of writing, these operations do not sign extend unnecessarily on 64 bit machines, unlike their int32 counterparts, and hence, are more performant. See the Int32
module for more details of the overhead entailed by the int32 byteswap functions.