//! Simple, shared algorithms for slices and iterators.

use crate::num::Integer;

/// Copy bytes from source to destination.

///

/// This is only used in our compact and radix integer formatted, so

/// performance isn't the highest consideration here.

#[inline(always)]

#[cfg(any(feature = "write-floats", feature = "write-integers"))]

pub fn copy_to_dst<T: Copy, Bytes: AsRef<[T]>>(dst: &mut [T], src: Bytes) -> usize {

    let src = src.as_ref();

    dst[..src.len()].copy_from_slice(src);

    src.len()

}

/// Count the number of trailing characters equal to a given value.

#[inline(always)]

#[cfg(any(feature = "write-floats", feature = "write-integers"))]

pub fn rtrim_char_count(slc: &[u8], c: u8) -> usize {

    slc.iter().rev().take_while(|&&si| si == c).count()

}

/// Count the number of leading characters equal to a given value.

#[inline(always)]

#[cfg(any(feature = "write-floats", feature = "write-integers"))]

pub fn ltrim_char_count(slc: &[u8], c: u8) -> usize {

    slc.iter().take_while(|&&si| si == c).count()

}

/// Check to see if parsing the float cannot possible overflow.

///

/// This allows major optimizations for those types, since we can skip checked

/// arithmetic. Adapted from the rust [corelib][`core`].

///

/// [`core`]: <https://doc.rust-lang.org/1.81.0/src/core/num/mod.rs.html#1389>

#[inline(always)]

pub fn cannot_overflow<T: Integer>(length: usize, radix: u32) -> bool {

    length <= T::overflow_digits(radix)

}