mod.rs - source
Description: Source of the Rust file `library/std/src/sys/helpers/mod.rs`.

#
std/sys/helpers/
mod.rs

    1//! Small helper functions used inside `sys`.
    2//!
    3//! If any of these have uses outside of `sys`, please move them to a different
    4//! module.
    5
    6#[cfg_attr(not(target_os = "linux"), allow(unused))] // Not used on all platforms.
    7mod small_c_string;
    8#[cfg_attr(not(target_os = "windows"), allow(unused))] // Not used on all platforms.
    9mod wstr;
    10
    11#[cfg(test)]
    12mod tests;
    13
    14#[cfg_attr(not(target_os = "linux"), allow(unused))] // Not used on all platforms.
    15pub use small_c_string::{run_path_with_cstr, run_with_cstr};
    16#[cfg_attr(not(target_os = "windows"), allow(unused))] // Not used on all platforms.
    17pub use wstr::WStrUnits;
    18
    19/// Computes `(value*numerator)/denom` without overflow, as long as both
    20/// `numerator*denom` and the overall result fit into `u64` (which is the case
    21/// for our time conversions).
    22#[cfg_attr(not(target_os = "windows"), allow(unused))] // Not used on all platforms.
    23pub fn mul_div_u64(value: u64, numerator: u64, denom: u64) -> u64 {
    24    let q = value / denom;
    25    let r = value % denom;
    26    // Decompose value as (value/denom*denom + value%denom),
    27    // substitute into (value*numerator)/denom and simplify.
    28    // r < denom, so (denom*numerator) is the upper bound of (r*numerator)
    29    q * numerator + r * numerator / denom
    30}
    31
    32#[cfg_attr(not(target_os = "linux"), allow(unused))] // Not used on all platforms.
    33pub fn ignore_notfound<T>(result: crate::io::Result<T>) -> crate::io::Result<()> {
    34    match result {
    35        Err(err) if err.kind() == crate::io::ErrorKind::NotFound => Ok(()),
    36        Ok(_) => Ok(()),
    37        Err(err) => Err(err),
    38    }
    39}