b483db4868
closes #373
270 lines
7.9 KiB
Zig
270 lines
7.9 KiB
Zig
const assert = @import("debug.zig").assert;
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const builtin = @import("builtin");
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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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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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pub fn log(comptime base: usize, value: var) -> @typeOf(value) {
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const T = @typeOf(value);
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switch (@typeId(T)) {
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builtin.TypeId.Int => {
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if (base == 2) {
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return T.bit_count - 1 - @clz(value);
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} else {
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@compileError("TODO implement log for non base 2 integers");
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}
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},
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builtin.TypeId.Float => {
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@compileError("TODO implement log for floats");
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},
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else => {
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@compileError("log expects integer or float, found '" ++ @typeName(T) ++ "'");
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},
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}
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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 fn absFloat(x: var) -> @typeOf(x) {
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comptime assert(@typeId(@typeOf(x)) == builtin.TypeId.Float);
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return if (x < 0) -x else x;
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}
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test "math.absFloat" {
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testAbsFloat();
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comptime testAbsFloat();
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}
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fn testAbsFloat() {
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assert(absFloat(f32(-10.0)) == 10.0);
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assert(absFloat(f32(10.0)) == 10.0);
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}
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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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fn isNan(comptime T: type, x: T) -> bool {
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assert(@typeId(T) == builtin.TypeId.Float);
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const bits = floatBits(x);
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if (T == f32) {
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return (bits & 0x7fffffff) > 0x7f800000;
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} else if (T == f64) {
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return (bits & (@maxValue(u64) >> 1)) > (u64(0x7ff) << 52);
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} else {
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unreachable;
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}
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}
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fn floatBits(comptime T: type, x: T) -> @IntType(false, T.bit_count) {
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assert(@typeId(T) == builtin.TypeId.Float);
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const uint = @IntType(false, T.bit_count);
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return *@intToPtr(&const uint, &x);
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}
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