silk.num.u32.

When to use#

Use u32 when an unsigned 32-bit representation is part of the contract, including masks and encoded fields. Use usize for collection positions and allocation sizes tied to the target.

Details#

Each arithmetic operation has four forms with different overflow rules:

• The plain form, such as add, traps on overflow. Use it when overflow is a program error.

• The checked form, such as checkedAdd, returns None on overflow. Use it when input data controls the operands.

• The wrapping form, such as wrappingAdd, computes the result modulo 2^32.

• The saturating form, such as saturatingAdd, returns MIN or MAX on overflow.

Division and remainder by zero trap. checkedDivide and checkedRemainder return None. The shift count must be in the range 0 to BITS - 1. Otherwise, the program traps. A rotate reduces its count modulo BITS, so each count is valid. A right shift inserts zero bits.

A to conversion, such as toU8, traps if the value is out of the range of the destination type. A checkedTo conversion returns None instead. Conversion to f32 or f64 rounds to the nearest value if the integer has more significant bits than the float.

A wrappingTo conversion, such as wrappingToI16, never traps. It keeps the low bits of the two's complement form of the value, like a cast in C or Rust, so it truncates, sign-extends, or reinterprets bits.

countOnes, leadingZeros, and trailingZeros count the bits of the value. For zero, both zero counts return BITS.

parse reads decimal text. A sign is not valid. To write a value as text, use silk.text.format.Format.display or Format.displayWith with a Writer. Neither needs an Allocator.

Examples#

Extract one byte from a fixed-width field#

import silk.num.u32

pub fn main() -> i32 {
  let shifted = u32.shiftRight(0x00002A00, 8)
  let byte = u32.bitAnd(shifted, 0xFF)
  let result = u32.toI32(byte)
  if result != 42 {
    return 1
  }
  return 0
}

Parse decimal text and reject invalid text#

import silk.text.format { ParseError }
import silk.core.result { Result }
import silk.num.u32

pub fn main() -> i32 {
  let parsed = u32.parse("42") |> Result<u32, ParseError>.unwrapOr(0)
  let invalid = u32.parse("4x2") |> Result<u32, ParseError>.unwrapOr(0)
  if parsed != 42 || invalid != 0 {
    return 1
  }
  return 0
}

Import as u32 with import silk.num.u32.

Public declarations: 70.

MAX#

pub const MAX: u32

The largest u32 value.

MIN#

pub const MIN: u32

The smallest u32 value.

BITS#

pub const BITS: u32

The fixed width of u32, in bits.

toU8#

pub fn toU8(value: u32) -> u8

Converts value to u8. Traps if value is outside the u8 range. Use this function when an out-of-range value is a program error.

checkedToU8#

pub fn checkedToU8(value: u32) -> Option<u8>

Converts value to u8, or returns None if value is outside the u8 range. Use this function when an out-of-range value is input data.

toU16#

pub fn toU16(value: u32) -> u16

Converts value to u16. Traps if value is outside the u16 range. Use this function when an out-of-range value is a program error.

checkedToU16#

pub fn checkedToU16(value: u32) -> Option<u16>

Converts value to u16, or returns None if value is outside the u16 range. Use this function when an out-of-range value is input data.

toU32#

pub fn toU32(value: u32) -> u32

Returns value unchanged as u32. Use this function when generic conversion code can select u32 as both source and destination.

checkedToU32#

pub fn checkedToU32(value: u32) -> Option<u32>

Returns Some with value unchanged as u32. Use this function when generic checked-conversion code can select the same source and destination type.

toU64#

pub fn toU64(value: u32) -> u64

Converts value exactly to u64. Every u32 value is representable.

checkedToU64#

pub fn checkedToU64(value: u32) -> Option<u64>

Converts value exactly to u64 and returns Some. Every u32 value is representable.

toUsize#

pub fn toUsize(value: u32) -> usize

Converts value exactly to usize. Every u32 value is representable.

checkedToUsize#

pub fn checkedToUsize(value: u32) -> Option<usize>

Converts value exactly to usize and returns Some. Every u32 value is representable.

toI8#

pub fn toI8(value: u32) -> i8

Converts value to i8. Traps if value is outside the i8 range. Use this function when an out-of-range value is a program error.

checkedToI8#

pub fn checkedToI8(value: u32) -> Option<i8>

Converts value to i8, or returns None if value is outside the i8 range. Use this function when an out-of-range value is input data.

toI16#

pub fn toI16(value: u32) -> i16

Converts value to i16. Traps if value is outside the i16 range. Use this function when an out-of-range value is a program error.

checkedToI16#

pub fn checkedToI16(value: u32) -> Option<i16>

Converts value to i16, or returns None if value is outside the i16 range. Use this function when an out-of-range value is input data.

toI32#

pub fn toI32(value: u32) -> i32

Converts value to i32. Traps if value is outside the i32 range. Use this function when an out-of-range value is a program error.

checkedToI32#

pub fn checkedToI32(value: u32) -> Option<i32>

Converts value to i32, or returns None if value is outside the i32 range. Use this function when an out-of-range value is input data.

toI64#

pub fn toI64(value: u32) -> i64

Converts value exactly to i64. Every u32 value is representable.

checkedToI64#

pub fn checkedToI64(value: u32) -> Option<i64>

Converts value exactly to i64 and returns Some. Every u32 value is representable.

toIsize#

pub fn toIsize(value: u32) -> isize

Converts value to isize. Traps if value is outside the isize range. Use this function when an out-of-range value is a program error.

checkedToIsize#

pub fn checkedToIsize(value: u32) -> Option<isize>

Converts value to isize, or returns None if value is outside the isize range. Use this function when an out-of-range value is input data.

toF32#

pub fn toF32(value: u32) -> f32

Converts value to the nearest f32 value, with ties to even. Only magnitudes below 2^24 are exactly representable, so a larger u32 rounds.

toF64#

pub fn toF64(value: u32) -> f64

Converts value exactly to f64. Every u32 value is below 2^53 and so is exactly representable.

wrappingToU8#

pub fn wrappingToU8(value: u32) -> u8

Converts value to u8 modulo 2^8. Keeps the low 8 bits of the two's complement form of value and reads them as u8, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

wrappingToU16#

pub fn wrappingToU16(value: u32) -> u16

Converts value to u16 modulo 2^16. Keeps the low 16 bits of the two's complement form of value and reads them as u16, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

wrappingToU32#

pub fn wrappingToU32(value: u32) -> u32

Returns value unchanged. Use this function when generic wrapping-conversion code can select u32 as both source and destination.

wrappingToU64#

pub fn wrappingToU64(value: u32) -> u64

Converts value to u64 modulo 2^64. Keeps the low 64 bits of the two's complement form of value and reads them as u64, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

wrappingToUsize#

pub fn wrappingToUsize(value: u32) -> usize

Converts value to usize modulo 2^usize.BITS. Keeps the low usize.BITS bits of the two's complement form of value and reads them as usize, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

wrappingToI8#

pub fn wrappingToI8(value: u32) -> i8

Converts value to i8 modulo 2^8. Keeps the low 8 bits of the two's complement form of value and reads them as i8, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

wrappingToI16#

pub fn wrappingToI16(value: u32) -> i16

Converts value to i16 modulo 2^16. Keeps the low 16 bits of the two's complement form of value and reads them as i16, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

wrappingToI32#

pub fn wrappingToI32(value: u32) -> i32

Converts value to i32 modulo 2^32. Keeps the low 32 bits of the two's complement form of value and reads them as i32, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

wrappingToI64#

pub fn wrappingToI64(value: u32) -> i64

Converts value to i64 modulo 2^64. Keeps the low 64 bits of the two's complement form of value and reads them as i64, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

wrappingToIsize#

pub fn wrappingToIsize(value: u32) -> isize

Converts value to isize modulo 2^isize.BITS. Keeps the low isize.BITS bits of the two's complement form of value and reads them as isize, so it never traps. Use this function for deliberate truncation, sign extension, or bit reinterpretation, such as reading a signed field.

add#

pub fn add(left: u32, right: u32) -> u32

Returns left + right and traps if the result is outside the u32 range. Use this function when overflow is a program error.

subtract#

pub fn subtract(left: u32, right: u32) -> u32

Returns left - right and traps if the result is outside the u32 range. Use this function when overflow is a program error.

multiply#

pub fn multiply(left: u32, right: u32) -> u32

Returns left * right and traps if the result is outside the u32 range. Use this function when overflow is a program error.

divide#

pub fn divide(left: u32, right: u32) -> u32

Returns left / right. Traps if right is zero. Use this function when a zero divisor is a program error.

remainder#

pub fn remainder(left: u32, right: u32) -> u32

Returns the remainder of left / right. Traps if right is zero. Use this function when a zero divisor is a program error.

bitAnd#

pub fn bitAnd(left: u32, right: u32) -> u32

Returns the bitwise AND of left and right.

bitOr#

pub fn bitOr(left: u32, right: u32) -> u32

Returns the bitwise OR of left and right.

bitXor#

pub fn bitXor(left: u32, right: u32) -> u32

Returns the bitwise exclusive OR of left and right.

bitNot#

pub fn bitNot(value: u32) -> u32

Returns value with each bit inverted.

shiftLeft#

pub fn shiftLeft(left: u32, right: u32) -> u32

Shifts left bits left by right positions. Traps if right is not less than BITS.

shiftRight#

pub fn shiftRight(left: u32, right: u32) -> u32

Shifts left bits right by right positions and inserts zero bits. Traps if right is not less than BITS.

rotateLeft#

pub fn rotateLeft(left: u32, right: u32) -> u32

Rotates the bits of left left by right positions. The count is reduced modulo BITS, so each count is valid.

rotateRight#

pub fn rotateRight(left: u32, right: u32) -> u32

Rotates the bits of left right by right positions. The count is reduced modulo BITS, so each count is valid.

countOnes#

pub fn countOnes(value: u32) -> u32

Returns the number of one bits in value.

leadingZeros#

pub fn leadingZeros(value: u32) -> u32

Returns the number of zero bits above the highest one bit of value. Returns BITS for zero.

trailingZeros#

pub fn trailingZeros(value: u32) -> u32

Returns the number of zero bits below the lowest one bit of value. Returns BITS for zero.

wrappingAdd#

pub fn wrappingAdd(left: u32, right: u32) -> u32

Returns left + right, wrapped to the u32 range. Use this function for deliberate modulo arithmetic.

wrappingSubtract#

pub fn wrappingSubtract(left: u32, right: u32) -> u32

Returns left - right, wrapped to the u32 range. Use this function for deliberate modulo arithmetic.

wrappingMultiply#

pub fn wrappingMultiply(left: u32, right: u32) -> u32

Returns left * right, wrapped to the u32 range. Use this function for deliberate modulo arithmetic.

saturatingAdd#

pub fn saturatingAdd(left: u32, right: u32) -> u32

Returns left + right, clamped to MIN or MAX. Use this function when a boundary value is the required overflow result.

saturatingSubtract#

pub fn saturatingSubtract(left: u32, right: u32) -> u32

Returns left - right, clamped to MIN or MAX. Use this function when a boundary value is the required overflow result.

saturatingMultiply#

pub fn saturatingMultiply(left: u32, right: u32) -> u32

Returns left * right, clamped to MIN or MAX. Use this function when a boundary value is the required overflow result.

multiplyHigh#

pub fn multiplyHigh(left: u32, right: u32) -> u32

Returns the high 32 bits of the exact 64-bit product left * right. It never overflows.

When to use#

Use this function with wrappingMultiply, which returns the low 32 bits, when an algorithm needs the full product, such as multi-word arithmetic, multiply-shift hashing, or division by a precomputed reciprocal.

checkedAdd#

pub fn checkedAdd(left: u32, right: u32) -> Option<u32>

Returns Some with left + right, or None if the result is outside the u32 range. Use this function when overflow is input data.

checkedSubtract#

pub fn checkedSubtract(left: u32, right: u32) -> Option<u32>

Returns Some with left - right, or None if the result is outside the u32 range. Use this function when overflow is input data.

checkedMultiply#

pub fn checkedMultiply(left: u32, right: u32) -> Option<u32>

Returns Some with left * right, or None if the result is outside the u32 range. Use this function when overflow is input data.

checkedDivide#

pub fn checkedDivide(left: u32, right: u32) -> Option<u32>

Returns Some with left / right, or None if right is zero. Use this function when a zero divisor is input data.

checkedRemainder#

pub fn checkedRemainder(left: u32, right: u32) -> Option<u32>

Returns Some with the remainder, or None if right is zero. Use this function when a zero divisor is input data.

equals#

pub fn equals(left: u32, right: u32) -> bool

Returns true if left and right are equal.

notEquals#

pub fn notEquals(left: u32, right: u32) -> bool

Returns true if left and right are not equal.

lessThan#

pub fn lessThan(left: u32, right: u32) -> bool

Returns true if left is less than right.

lessOrEqual#

pub fn lessOrEqual(left: u32, right: u32) -> bool

Returns true if left is less than or equal to right.

greaterThan#

pub fn greaterThan(left: u32, right: u32) -> bool

Returns true if left is greater than right.

greaterOrEqual#

pub fn greaterOrEqual(left: u32, right: u32) -> bool

Returns true if left is greater than or equal to right.

parse#

pub fn parse(text: string) -> Result<u32, ParseError>

Returns the u32 value of the decimal text text, or a ParseError.

Details#

The complete text must be one decimal number. This function does not skip spaces and does not accept digit separators.

Errors#

• ParseError with reason silk.text.format.NotANumber if text is empty, has a sign, contains a byte that is not a digit, or has bytes after the number. offset gives the byte position where the read stopped.

• ParseError with reason silk.text.format.OutOfRange if the number is outside the range of u32.

Category: Numbers.

Profiles: aarch64-apple-darwin, aarch64-unknown-linux-gnu, aarch64-unknown-linux-gnu-no-libc, x86_64-unknown-linux-gnu, x86_64-unknown-linux-gnu-no-libc, wasm32-unknown-unknown, wasm32-wasip1, wasm32-wasip2.