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use core::mem::size_of;
use crate::errors::InvalidParams;
#[cfg(feature = "simple")]
use password_hash::{errors::InvalidValue, Error, ParamsString, PasswordHash};
#[derive(Clone, Copy, Debug)]
pub struct Params {
pub(crate) log_n: u8,
pub(crate) r: u32,
pub(crate) p: u32,
#[allow(dead_code)] pub(crate) len: usize,
}
impl Params {
pub const RECOMMENDED_LOG_N: u8 = 17;
pub const RECOMMENDED_R: u32 = 8;
pub const RECOMMENDED_P: u32 = 1;
pub const RECOMMENDED_LEN: usize = 32;
pub fn new(log_n: u8, r: u32, p: u32, len: usize) -> Result<Params, InvalidParams> {
let cond1 = (log_n as usize) < usize::BITS as usize;
let cond2 = size_of::<usize>() >= size_of::<u32>();
let cond3 = r <= usize::MAX as u32 && p < usize::MAX as u32;
let cond4 = (10..=64).contains(&len);
if !(r > 0 && p > 0 && cond1 && (cond2 || cond3) && cond4) {
return Err(InvalidParams);
}
let r = r as usize;
let p = p as usize;
let n: usize = 1 << log_n;
let r128 = r.checked_mul(128).ok_or(InvalidParams)?;
r128.checked_mul(n).ok_or(InvalidParams)?;
r128.checked_mul(p).ok_or(InvalidParams)?;
if (log_n as usize) >= r * 16 {
return Err(InvalidParams);
}
if r * p >= 0x4000_0000 {
return Err(InvalidParams);
}
Ok(Params {
log_n,
r: r as u32,
p: p as u32,
len,
})
}
pub fn recommended() -> Params {
Params {
log_n: Self::RECOMMENDED_LOG_N,
r: Self::RECOMMENDED_R,
p: Self::RECOMMENDED_P,
len: Self::RECOMMENDED_LEN,
}
}
pub fn log_n(&self) -> u8 {
self.log_n
}
pub fn r(&self) -> u32 {
self.r
}
pub fn p(&self) -> u32 {
self.p
}
}
impl Default for Params {
fn default() -> Params {
Params::recommended()
}
}
#[cfg(feature = "simple")]
#[cfg_attr(docsrs, doc(cfg(feature = "simple")))]
impl<'a> TryFrom<&'a PasswordHash<'a>> for Params {
type Error = password_hash::Error;
fn try_from(hash: &'a PasswordHash<'a>) -> Result<Self, password_hash::Error> {
let mut log_n = Self::RECOMMENDED_LOG_N;
let mut r = Self::RECOMMENDED_R;
let mut p = Self::RECOMMENDED_P;
if hash.version.is_some() {
return Err(Error::Version);
}
for (ident, value) in hash.params.iter() {
match ident.as_str() {
"ln" => {
log_n = value
.decimal()?
.try_into()
.map_err(|_| InvalidValue::Malformed.param_error())?
}
"r" => r = value.decimal()?,
"p" => p = value.decimal()?,
_ => return Err(password_hash::Error::ParamNameInvalid),
}
}
let len = hash
.hash
.map(|out| out.len())
.unwrap_or(Self::RECOMMENDED_LEN);
Params::new(log_n, r, p, len).map_err(|_| InvalidValue::Malformed.param_error())
}
}
#[cfg(feature = "simple")]
#[cfg_attr(docsrs, doc(cfg(feature = "simple")))]
impl TryFrom<Params> for ParamsString {
type Error = password_hash::Error;
fn try_from(input: Params) -> Result<ParamsString, password_hash::Error> {
let mut output = ParamsString::new();
output.add_decimal("ln", input.log_n as u32)?;
output.add_decimal("r", input.r)?;
output.add_decimal("p", input.p)?;
Ok(output)
}
}