Int8.md

Int8

Provides utility functions on 8-bit signed integers.

Note that most operations are available as built-in operators (e.g. 1 + 1).

Import from the base library to use this module.

import Int8 "mo:base/Int8";

Type Int8

type Int8 = Prim.Types.Int8

8-bit signed integers.

Value minimumValue

let minimumValue : Int8

Minimum 8-bit integer value, -2 ** 7.

Example:

Int8.minimumValue // => -128

Value maximumValue

let maximumValue : Int8

Maximum 8-bit integer value, +2 ** 7 - 1.

Example:

Int8.maximumValue // => +127

Value toInt

let toInt : Int8 -> Int

Converts an 8-bit signed integer to a signed integer with infinite precision.

Example:

Int8.toInt(123) // => 123 : Int

Value fromInt

let fromInt : Int -> Int8

Converts a signed integer with infinite precision to an 8-bit signed integer.

Traps on overflow/underflow.

Example:

Int8.fromInt(123) // => +123 : Int8

Value fromIntWrap

let fromIntWrap : Int -> Int8

Converts a signed integer with infinite precision to an 8-bit signed integer.

Wraps on overflow/underflow.

Example:

Int8.fromIntWrap(-123) // => -123 : Int

Value fromInt16

let fromInt16 : Int16 -> Int8

Converts a 16-bit signed integer to an 8-bit signed integer.

Traps on overflow/underflow.

Example:

Int8.fromInt16(123) // => +123 : Int8

Value toInt16

let toInt16 : Int8 -> Int16

Converts an 8-bit signed integer to a 16-bit signed integer.

Example:

Int8.toInt16(123) // => +123 : Int16

Value fromNat8

let fromNat8 : Nat8 -> Int8

Converts an unsigned 8-bit integer to a signed 8-bit integer.

Wraps on overflow/underflow.

Example:

Int8.fromNat8(123) // => +123 : Int8

Value toNat8

let toNat8 : Int8 -> Nat8

Converts a signed 8-bit integer to an unsigned 8-bit integer.

Wraps on overflow/underflow.

Example:

Int8.toNat8(-1) // => 255 : Nat8 // underflow

Function toText

func toText(x : Int8) : Text

Converts an integer number to its textual representation.

Example:

Int8.toText(-123) // => "-123"

Function abs

func abs(x : Int8) : Int8

Returns the absolute value of x.

Traps when x == -2 ** 7 (the minimum Int8 value).

Example:

Int8.abs(-123) // => +123

Function min

func min(x : Int8, y : Int8) : Int8

Returns the minimum of x and y.

Example:

Int8.min(+2, -3) // => -3

Function max

func max(x : Int8, y : Int8) : Int8

Returns the maximum of x and y.

Example:

Int8.max(+2, -3) // => +2

Function equal

func equal(x : Int8, y : Int8) : Bool

Equality function for Int8 types. This is equivalent to x == y.

Example:

Int8.equal(-1, -1); // => true

Note: The reason why this function is defined in this library (in addition to the existing == operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use == as a function value at the moment.

Example:

import Buffer "mo:base/Buffer";

let buffer1 = Buffer.Buffer<Int8>(1);
buffer1.add(-3);
let buffer2 = Buffer.Buffer<Int8>(1);
buffer2.add(-3);
Buffer.equal(buffer1, buffer2, Int8.equal) // => true

Function notEqual

func notEqual(x : Int8, y : Int8) : Bool

Inequality function for Int8 types. This is equivalent to x != y.

Example:

Int8.notEqual(-1, -2); // => true

Note: The reason why this function is defined in this library (in addition to the existing != operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use != as a function value at the moment.

Function less

func less(x : Int8, y : Int8) : Bool

"Less than" function for Int8 types. This is equivalent to x < y.

Example:

Int8.less(-2, 1); // => true

Note: The reason why this function is defined in this library (in addition to the existing < operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use < as a function value at the moment.

Function lessOrEqual

func lessOrEqual(x : Int8, y : Int8) : Bool

"Less than or equal" function for Int8 types. This is equivalent to x <= y.

Example:

Int8.lessOrEqual(-2, -2); // => true

Note: The reason why this function is defined in this library (in addition to the existing <= operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use <= as a function value at the moment.

Function greater

func greater(x : Int8, y : Int8) : Bool

"Greater than" function for Int8 types. This is equivalent to x > y.

Example:

Int8.greater(-2, -3); // => true

Note: The reason why this function is defined in this library (in addition to the existing > operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use > as a function value at the moment.

Function greaterOrEqual

func greaterOrEqual(x : Int8, y : Int8) : Bool

"Greater than or equal" function for Int8 types. This is equivalent to x >= y.

Example:

Int8.greaterOrEqual(-2, -2); // => true

Note: The reason why this function is defined in this library (in addition to the existing >= operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use >= as a function value at the moment.

Function compare

func compare(x : Int8, y : Int8) : {#less; #equal; #greater}

General-purpose comparison function for Int8. Returns the Order ( either #less, #equal, or #greater) of comparing x with y.

Example:

Int8.compare(-3, 2) // => #less

This function can be used as value for a high order function, such as a sort function.

Example:

import Array "mo:base/Array";
Array.sort([1, -2, -3] : [Int8], Int8.compare) // => [-3, -2, 1]

Function neg

func neg(x : Int8) : Int8

Returns the negation of x, -x.

Traps on overflow, i.e. for neg(-2 ** 7).

Example:

Int8.neg(123) // => -123

Note: The reason why this function is defined in this library (in addition to the existing - operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use - as a function value at the moment.

Function add

func add(x : Int8, y : Int8) : Int8

Returns the sum of x and y, x + y.

Traps on overflow/underflow.

Example:

Int8.add(100, 23) // => +123

Note: The reason why this function is defined in this library (in addition to the existing + operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use + as a function value at the moment.

Example:

import Array "mo:base/Array";
Array.foldLeft<Int8, Int8>([1, -2, -3], 0, Int8.add) // => -4

Function sub

func sub(x : Int8, y : Int8) : Int8

Returns the difference of x and y, x - y.

Traps on overflow/underflow.

Example:

Int8.sub(123, 23) // => +100

Note: The reason why this function is defined in this library (in addition to the existing - operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use - as a function value at the moment.

Example:

import Array "mo:base/Array";
Array.foldLeft<Int8, Int8>([1, -2, -3], 0, Int8.sub) // => 4

Function mul

func mul(x : Int8, y : Int8) : Int8

Returns the product of x and y, x * y.

Traps on overflow/underflow.

Example:

Int8.mul(12, 10) // => +120

Note: The reason why this function is defined in this library (in addition to the existing * operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use * as a function value at the moment.

Example:

import Array "mo:base/Array";
Array.foldLeft<Int8, Int8>([1, -2, -3], 1, Int8.mul) // => 6

Function div

func div(x : Int8, y : Int8) : Int8

Returns the signed integer division of x by y, x / y. Rounds the quotient towards zero, which is the same as truncating the decimal places of the quotient.

Traps when y is zero.

Example:

Int8.div(123, 10) // => +12

Note: The reason why this function is defined in this library (in addition to the existing / operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use / as a function value at the moment.

Function rem

func rem(x : Int8, y : Int8) : Int8

Returns the remainder of the signed integer division of x by y, x % y, which is defined as x - x / y * y.

Traps when y is zero.

Example:

Int8.rem(123, 10) // => +3

Note: The reason why this function is defined in this library (in addition to the existing % operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use % as a function value at the moment.

Function pow

func pow(x : Int8, y : Int8) : Int8

Returns x to the power of y, x ** y.

Traps on overflow/underflow and when y < 0 or y >= 8.

Example:

Int8.pow(2, 6) // => +64

Note: The reason why this function is defined in this library (in addition to the existing ** operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use ** as a function value at the moment.

Function bitnot

func bitnot(x : Int8) : Int8

Returns the bitwise negation of x, ^x.

Example:

Int8.bitnot(-16 /* 0xf0 */) // => +15 // 0x0f

Note: The reason why this function is defined in this library (in addition to the existing ^ operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use ^ as a function value at the moment.

Function bitand

func bitand(x : Int8, y : Int8) : Int8

Returns the bitwise "and" of x and y, x & y.

Example:

Int8.bitand(0x1f, 0x70) // => +16 // 0x10

Note: The reason why this function is defined in this library (in addition to the existing & operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use & as a function value at the moment.

Function bitor

func bitor(x : Int8, y : Int8) : Int8

Returns the bitwise "or" of x and y, x | y.

Example:

Int8.bitor(0x0f, 0x70) // => +127 // 0x7f

Note: The reason why this function is defined in this library (in addition to the existing | operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use | as a function value at the moment.

Function bitxor

func bitxor(x : Int8, y : Int8) : Int8

Returns the bitwise "exclusive or" of x and y, x ^ y.

Example:

Int8.bitxor(0x70, 0x7f) // => +15 // 0x0f

Note: The reason why this function is defined in this library (in addition to the existing ^ operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use ^ as a function value at the moment.

Function bitshiftLeft

func bitshiftLeft(x : Int8, y : Int8) : Int8

Returns the bitwise left shift of x by y, x << y. The right bits of the shift filled with zeros. Left-overflowing bits, including the sign bit, are discarded.

For y >= 8, the semantics is the same as for bitshiftLeft(x, y % 8). For y < 0, the semantics is the same as for bitshiftLeft(x, y + y % 8).

Example:

Int8.bitshiftLeft(1, 4) // => +16 // 0x10 equivalent to `2 ** 4`.

Note: The reason why this function is defined in this library (in addition to the existing << operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use << as a function value at the moment.

Function bitshiftRight

func bitshiftRight(x : Int8, y : Int8) : Int8

Returns the signed bitwise right shift of x by y, x >> y. The sign bit is retained and the left side is filled with the sign bit. Right-underflowing bits are discarded, i.e. not rotated to the left side.

For y >= 8, the semantics is the same as for bitshiftRight(x, y % 8). For y < 0, the semantics is the same as for bitshiftRight (x, y + y % 8).

Example:

Int8.bitshiftRight(64, 4) // => +4 // equivalent to `64 / (2 ** 4)`

Note: The reason why this function is defined in this library (in addition to the existing >> operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use >> as a function value at the moment.

Function bitrotLeft

func bitrotLeft(x : Int8, y : Int8) : Int8

Returns the bitwise left rotatation of x by y, x <<> y. Each left-overflowing bit is inserted again on the right side. The sign bit is rotated like other bits, i.e. the rotation interprets the number as unsigned.

Changes the direction of rotation for negative y. For y >= 8, the semantics is the same as for bitrotLeft(x, y % 8).

Example:

Int8.bitrotLeft(0x11 /* 0b0001_0001 */, 2) // => +68 // 0b0100_0100 == 0x44.

Note: The reason why this function is defined in this library (in addition to the existing <<> operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use <<> as a function value at the moment.

Function bitrotRight

func bitrotRight(x : Int8, y : Int8) : Int8

Returns the bitwise right rotation of x by y, x <>> y. Each right-underflowing bit is inserted again on the right side. The sign bit is rotated like other bits, i.e. the rotation interprets the number as unsigned.

Changes the direction of rotation for negative y. For y >= 8, the semantics is the same as for bitrotRight(x, y % 8).

Example:

Int8.bitrotRight(0x11 /* 0b0001_0001 */, 1) // => -120 // 0b1000_1000 == 0x88.

Note: The reason why this function is defined in this library (in addition to the existing <>> operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use <>> as a function value at the moment.

Function bittest

func bittest(x : Int8, p : Nat) : Bool

Returns the value of bit p in x, x & 2**p == 2**p. If p >= 8, the semantics is the same as for bittest(x, p % 8). This is equivalent to checking if the p-th bit is set in x, using 0 indexing.

Example:

Int8.bittest(64, 6) // => true

Function bitset

func bitset(x : Int8, p : Nat) : Int8

Returns the value of setting bit p in x to 1. If p >= 8, the semantics is the same as for bitset(x, p % 8).

Example:

Int8.bitset(0, 6) // => +64

Function bitclear

func bitclear(x : Int8, p : Nat) : Int8

Returns the value of clearing bit p in x to 0. If p >= 8, the semantics is the same as for bitclear(x, p % 8).

Example:

Int8.bitclear(-1, 6) // => -65

Function bitflip

func bitflip(x : Int8, p : Nat) : Int8

Returns the value of flipping bit p in x. If p >= 8, the semantics is the same as for bitclear(x, p % 8).

Example:

Int8.bitflip(127, 6) // => +63

Value bitcountNonZero

let bitcountNonZero : (x : Int8) -> Int8

Returns the count of non-zero bits in x.

Example:

Int8.bitcountNonZero(0x0f) // => +4

Value bitcountLeadingZero

let bitcountLeadingZero : (x : Int8) -> Int8

Returns the count of leading zero bits in x.

Example:

Int8.bitcountLeadingZero(0x08) // => +4

Value bitcountTrailingZero

let bitcountTrailingZero : (x : Int8) -> Int8

Returns the count of trailing zero bits in x.

Example:

Int8.bitcountTrailingZero(0x10) // => +4

Function addWrap

func addWrap(x : Int8, y : Int8) : Int8

Returns the sum of x and y, x +% y.

Wraps on overflow/underflow.

Example:

Int8.addWrap(2 ** 6, 2 ** 6) // => -128 // overflow

Note: The reason why this function is defined in this library (in addition to the existing +% operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use +% as a function value at the moment.

Function subWrap

func subWrap(x : Int8, y : Int8) : Int8

Returns the difference of x and y, x -% y.

Wraps on overflow/underflow.

Example:

Int8.subWrap(-2 ** 7, 1) // => +127 // underflow

Note: The reason why this function is defined in this library (in addition to the existing -% operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use -% as a function value at the moment.

Function mulWrap

func mulWrap(x : Int8, y : Int8) : Int8

Returns the product of x and y, x *% y. Wraps on overflow.

Wraps on overflow/underflow.

Example:

Int8.mulWrap(2 ** 4, 2 ** 4) // => 0 // overflow

Note: The reason why this function is defined in this library (in addition to the existing *% operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use *% as a function value at the moment.

Function powWrap

func powWrap(x : Int8, y : Int8) : Int8

Returns x to the power of y, x **% y.

Wraps on overflow/underflow. Traps if y < 0 or y >= 8.

Example:

Int8.powWrap(2, 7) // => -128 // overflow

Note: The reason why this function is defined in this library (in addition to the existing **% operator) is so that you can use it as a function value to pass to a higher order function. It is not possible to use **% as a function value at the moment.