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Speed up StorePath::to_string()

Browse source 
1.81% -> 0.56%
This commit is contained in:
Eelco Dolstra 2019-12-10 20:48:36 +01:00
parent f64b58b45e
commit f800d450b7
3 changed files with 24 additions and 8 deletions
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9
nix-rust/src/c.rs
View file

@ -1,6 +1,7 @@
use super::{
error,
foreign::{self, CBox},
store::path,
store::StorePath,
util,
};
@ -53,8 +54,12 @@ pub unsafe extern "C" fn ffi_StorePath_drop(self_: *mut StorePath) {
}
#[no_mangle]
pub extern "C" fn ffi_StorePath_to_string(self_: &StorePath) -> String {
format!("{}", self_)
pub extern "C" fn ffi_StorePath_to_string(self_: &StorePath) -> Vec<u8> {
let mut buf = vec![0; path::STORE_PATH_HASH_CHARS + 1 + self_.name.name().len()];
util::base32::encode_into(self_.hash.hash(), &mut buf[0..path::STORE_PATH_HASH_CHARS]);
buf[path::STORE_PATH_HASH_CHARS] = b'-';
buf[path::STORE_PATH_HASH_CHARS + 1..].clone_from_slice(self_.name.name().as_bytes());
buf
}
#[no_mangle]

4
nix-rust/src/store/path.rs
View file

@ -70,7 +70,9 @@ impl StorePathHash {
impl fmt::Display for StorePathHash {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(&base32::encode(&self.0))
let mut buf = vec![0; STORE_PATH_HASH_CHARS];
base32::encode_into(&self.0, &mut buf);
f.write_str(std::str::from_utf8(&buf).unwrap())
}
}

19
nix-rust/src/util/base32.rs
View file

@ -25,27 +25,36 @@ lazy_static! {
}
pub fn encode(input: &[u8]) -> String {
let mut res = String::new();
res.reserve(encoded_len(input.len()));
let mut buf = vec![0; encoded_len(input.len())];
encode_into(input, &mut buf);
std::str::from_utf8(&buf).unwrap().to_string()
}
pub fn encode_into(input: &[u8], output: &mut [u8]) {
let len = encoded_len(input.len());
assert_eq!(len, output.len());
let mut nr_bits_left: usize = 0;
let mut bits_left: u16 = 0;
let mut pos = len;
for b in input {
bits_left |= (*b as u16) << nr_bits_left;
nr_bits_left += 8;
while nr_bits_left > 5 {
res.push(BASE32_CHARS[(bits_left & 0x1f) as usize] as char);
output[pos - 1] = BASE32_CHARS[(bits_left & 0x1f) as usize];
pos -= 1;
bits_left >>= 5;
nr_bits_left -= 5;
}
}
if nr_bits_left > 0 {
res.push(BASE32_CHARS[(bits_left & 0x1f) as usize] as char);
output[pos - 1] = BASE32_CHARS[(bits_left & 0x1f) as usize];
pos -= 1;
}
res.chars().rev().collect()
assert_eq!(pos, 0);
}
pub fn decode(input: &str) -> Result<Vec<u8>, crate::Error> {