mirror of
https://github.com/ziglang/zig.git
synced 2025-12-15 18:53:07 +00:00
4c16f9a3c3
This covers the majority of the functions as covered by the C99 specification for a math library. Code is adapted primarily from musl libc, with the pow and standard trigonometric functions adapted from the Go stdlib. Changes: - Remove assert expose in index and import as needed. - Add float log function and merge with existing base 2 integer implementation. See https://github.com/tiehuis/zig-fmath. See #374.
275 lines
8.0 KiB
Zig
275 lines
8.0 KiB
Zig
const assert = @import("../debug.zig").assert;
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const builtin = @import("builtin");
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pub const frexp = @import("frexp.zig").frexp;
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pub const Cmp = enum {
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Less,
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Equal,
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Greater,
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};
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pub fn min(x: var, y: var) -> @typeOf(x + y) {
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if (x < y) x else y
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}
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test "math.min" {
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assert(min(i32(-1), i32(2)) == -1);
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}
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pub fn max(x: var, y: var) -> @typeOf(x + y) {
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if (x > y) x else y
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}
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test "math.max" {
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assert(max(i32(-1), i32(2)) == 2);
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}
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error Overflow;
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pub fn mul(comptime T: type, a: T, b: T) -> %T {
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var answer: T = undefined;
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if (@mulWithOverflow(T, a, b, &answer)) error.Overflow else answer
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}
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error Overflow;
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pub fn add(comptime T: type, a: T, b: T) -> %T {
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var answer: T = undefined;
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if (@addWithOverflow(T, a, b, &answer)) error.Overflow else answer
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}
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error Overflow;
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pub fn sub(comptime T: type, a: T, b: T) -> %T {
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var answer: T = undefined;
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if (@subWithOverflow(T, a, b, &answer)) error.Overflow else answer
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}
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pub fn negate(x: var) -> %@typeOf(x) {
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return sub(@typeOf(x), 0, x);
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}
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error Overflow;
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pub fn shl(comptime T: type, a: T, b: T) -> %T {
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var answer: T = undefined;
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if (@shlWithOverflow(T, a, b, &answer)) error.Overflow else answer
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}
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test "math overflow functions" {
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testOverflow();
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comptime testOverflow();
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}
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fn testOverflow() {
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assert(%%mul(i32, 3, 4) == 12);
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assert(%%add(i32, 3, 4) == 7);
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assert(%%sub(i32, 3, 4) == -1);
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assert(%%shl(i32, 0b11, 4) == 0b110000);
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}
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error Overflow;
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pub fn absInt(x: var) -> %@typeOf(x) {
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const T = @typeOf(x);
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comptime assert(@typeId(T) == builtin.TypeId.Int); // must pass an integer to absInt
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comptime assert(T.is_signed); // must pass a signed integer to absInt
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if (x == @minValue(@typeOf(x)))
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return error.Overflow;
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{
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@setDebugSafety(this, false);
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return if (x < 0) -x else x;
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}
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}
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test "math.absInt" {
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testAbsInt();
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comptime testAbsInt();
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}
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fn testAbsInt() {
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assert(%%absInt(i32(-10)) == 10);
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assert(%%absInt(i32(10)) == 10);
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}
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pub const absFloat = @import("fabs.zig").fabs;
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error DivisionByZero;
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error Overflow;
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pub fn divTrunc(comptime T: type, numerator: T, denominator: T) -> %T {
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@setDebugSafety(this, false);
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if (denominator == 0)
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return error.DivisionByZero;
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if (@typeId(T) == builtin.TypeId.Int and T.is_signed and numerator == @minValue(T) and denominator == -1)
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return error.Overflow;
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return @divTrunc(numerator, denominator);
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}
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test "math.divTrunc" {
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testDivTrunc();
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comptime testDivTrunc();
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}
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fn testDivTrunc() {
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assert(%%divTrunc(i32, 5, 3) == 1);
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assert(%%divTrunc(i32, -5, 3) == -1);
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if (divTrunc(i8, -5, 0)) |_| unreachable else |err| assert(err == error.DivisionByZero);
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if (divTrunc(i8, -128, -1)) |_| unreachable else |err| assert(err == error.Overflow);
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assert(%%divTrunc(f32, 5.0, 3.0) == 1.0);
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assert(%%divTrunc(f32, -5.0, 3.0) == -1.0);
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}
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error DivisionByZero;
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error Overflow;
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pub fn divFloor(comptime T: type, numerator: T, denominator: T) -> %T {
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@setDebugSafety(this, false);
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if (denominator == 0)
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return error.DivisionByZero;
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if (@typeId(T) == builtin.TypeId.Int and T.is_signed and numerator == @minValue(T) and denominator == -1)
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return error.Overflow;
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return @divFloor(numerator, denominator);
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}
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test "math.divFloor" {
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testDivFloor();
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comptime testDivFloor();
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}
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fn testDivFloor() {
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assert(%%divFloor(i32, 5, 3) == 1);
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assert(%%divFloor(i32, -5, 3) == -2);
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if (divFloor(i8, -5, 0)) |_| unreachable else |err| assert(err == error.DivisionByZero);
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if (divFloor(i8, -128, -1)) |_| unreachable else |err| assert(err == error.Overflow);
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assert(%%divFloor(f32, 5.0, 3.0) == 1.0);
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assert(%%divFloor(f32, -5.0, 3.0) == -2.0);
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}
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error DivisionByZero;
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error Overflow;
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error UnexpectedRemainder;
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pub fn divExact(comptime T: type, numerator: T, denominator: T) -> %T {
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@setDebugSafety(this, false);
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if (denominator == 0)
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return error.DivisionByZero;
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if (@typeId(T) == builtin.TypeId.Int and T.is_signed and numerator == @minValue(T) and denominator == -1)
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return error.Overflow;
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const result = @divTrunc(numerator, denominator);
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if (result * denominator != numerator)
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return error.UnexpectedRemainder;
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return result;
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}
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test "math.divExact" {
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testDivExact();
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comptime testDivExact();
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}
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fn testDivExact() {
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assert(%%divExact(i32, 10, 5) == 2);
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assert(%%divExact(i32, -10, 5) == -2);
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if (divExact(i8, -5, 0)) |_| unreachable else |err| assert(err == error.DivisionByZero);
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if (divExact(i8, -128, -1)) |_| unreachable else |err| assert(err == error.Overflow);
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if (divExact(i32, 5, 2)) |_| unreachable else |err| assert(err == error.UnexpectedRemainder);
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assert(%%divExact(f32, 10.0, 5.0) == 2.0);
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assert(%%divExact(f32, -10.0, 5.0) == -2.0);
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if (divExact(f32, 5.0, 2.0)) |_| unreachable else |err| assert(err == error.UnexpectedRemainder);
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}
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error DivisionByZero;
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error NegativeDenominator;
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pub fn mod(comptime T: type, numerator: T, denominator: T) -> %T {
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@setDebugSafety(this, false);
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if (denominator == 0)
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return error.DivisionByZero;
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if (denominator < 0)
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return error.NegativeDenominator;
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return @mod(numerator, denominator);
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}
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test "math.mod" {
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testMod();
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comptime testMod();
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}
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fn testMod() {
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assert(%%mod(i32, -5, 3) == 1);
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assert(%%mod(i32, 5, 3) == 2);
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if (mod(i32, 10, -1)) |_| unreachable else |err| assert(err == error.NegativeDenominator);
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if (mod(i32, 10, 0)) |_| unreachable else |err| assert(err == error.DivisionByZero);
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assert(%%mod(f32, -5, 3) == 1);
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assert(%%mod(f32, 5, 3) == 2);
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if (mod(f32, 10, -1)) |_| unreachable else |err| assert(err == error.NegativeDenominator);
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if (mod(f32, 10, 0)) |_| unreachable else |err| assert(err == error.DivisionByZero);
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}
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error DivisionByZero;
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error NegativeDenominator;
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pub fn rem(comptime T: type, numerator: T, denominator: T) -> %T {
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@setDebugSafety(this, false);
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if (denominator == 0)
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return error.DivisionByZero;
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if (denominator < 0)
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return error.NegativeDenominator;
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return @rem(numerator, denominator);
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}
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test "math.rem" {
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testRem();
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comptime testRem();
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}
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fn testRem() {
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assert(%%rem(i32, -5, 3) == -2);
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assert(%%rem(i32, 5, 3) == 2);
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if (rem(i32, 10, -1)) |_| unreachable else |err| assert(err == error.NegativeDenominator);
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if (rem(i32, 10, 0)) |_| unreachable else |err| assert(err == error.DivisionByZero);
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assert(%%rem(f32, -5, 3) == -2);
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assert(%%rem(f32, 5, 3) == 2);
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if (rem(f32, 10, -1)) |_| unreachable else |err| assert(err == error.NegativeDenominator);
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if (rem(f32, 10, 0)) |_| unreachable else |err| assert(err == error.DivisionByZero);
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}
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/// Returns the absolute value of the integer parameter.
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/// Result is an unsigned integer.
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pub fn absCast(x: var) -> @IntType(false, @typeOf(x).bit_count) {
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const uint = @IntType(false, @typeOf(x).bit_count);
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if (x >= 0)
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return uint(x);
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return uint(-(x + 1)) + 1;
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}
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test "math.absCast" {
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assert(absCast(i32(-999)) == 999);
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assert(@typeOf(absCast(i32(-999))) == u32);
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assert(absCast(i32(999)) == 999);
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assert(@typeOf(absCast(i32(999))) == u32);
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assert(absCast(i32(@minValue(i32))) == -@minValue(i32));
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assert(@typeOf(absCast(i32(@minValue(i32)))) == u32);
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}
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/// Returns the negation of the integer parameter.
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/// Result is a signed integer.
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error Overflow;
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pub fn negateCast(x: var) -> %@IntType(true, @typeOf(x).bit_count) {
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if (@typeOf(x).is_signed)
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return negate(x);
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const int = @IntType(true, @typeOf(x).bit_count);
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if (x > -@minValue(int))
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return error.Overflow;
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if (x == -@minValue(int))
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return @minValue(int);
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return -int(x);
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}
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test "math.negateCast" {
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assert(%%negateCast(u32(999)) == -999);
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assert(@typeOf(%%negateCast(u32(999))) == i32);
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assert(%%negateCast(u32(-@minValue(i32))) == @minValue(i32));
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assert(@typeOf(%%negateCast(u32(-@minValue(i32)))) == i32);
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if (negateCast(u32(@maxValue(i32) + 10))) |_| unreachable else |err| assert(err == error.Overflow);
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}
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