From 2a89d061a01ab43df67459bfaaf578d7fb41fc54 Mon Sep 17 00:00:00 2001
From: Fabian Schmidt <fabschmidt96@gmail.com>
Date: Mon, 19 Aug 2024 10:57:18 +0200
Subject: [PATCH] Use FxHashMap for multi_threaded_smol.rs

---
 .../implementations/multi_threaded_smol.rs    | 29 +++++++++----------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/src/main/rust/src/implementations/multi_threaded_smol.rs b/src/main/rust/src/implementations/multi_threaded_smol.rs
index 85f8a7e..914df71 100644
--- a/src/main/rust/src/implementations/multi_threaded_smol.rs
+++ b/src/main/rust/src/implementations/multi_threaded_smol.rs
@@ -1,10 +1,9 @@
 use smol::fs::File;
 use smol::io::{AsyncBufReadExt, AsyncSeekExt, BufReader, SeekFrom};
+use rustc_hash::{FxHashMap as HashMap, FxBuildHasher};
 
 use crate::models::station_measurements::StationMeasurements;
 use crate::utils::parse;
-use crate::utils::parse::hashstr;
-use std::collections::HashMap;
 use std::sync::mpsc;
 use std::thread;
 use std::time::Instant;
@@ -15,8 +14,9 @@ pub fn run() {
     const FILE_PATH: &str = "../../../measurements.txt";
     let now = Instant::now();
     thread::scope(|s| {
-        let mut stations: HashMap<usize, (String, StationMeasurements)> =
-            HashMap::with_capacity(DEFAULT_HASHMAP_LENGTH);
+        let hasher = FxBuildHasher::default();
+        let mut stations: HashMap<String, StationMeasurements> =
+            HashMap::with_capacity_and_hasher(DEFAULT_HASHMAP_LENGTH, hasher);
         let (tx, rx) = mpsc::channel();
         let cores = thread::available_parallelism().unwrap().into();
         let bounds = smol::block_on(async {
@@ -57,8 +57,8 @@ pub fn run() {
                         .expect("File measurements.txt not found");
                     let mut reader = BufReader::new(&mut file);
                     reader.seek(SeekFrom::Start(currposition)).await.unwrap();
-                    let mut t_stations: HashMap<usize, (String, StationMeasurements)> =
-                        HashMap::with_capacity(DEFAULT_HASHMAP_LENGTH);
+                    let mut t_stations: HashMap<String, StationMeasurements> =
+                        HashMap::with_capacity_and_hasher(DEFAULT_HASHMAP_LENGTH, hasher);
                     let mut line = Vec::with_capacity(108);
                     loop {
                         let line_len = reader
@@ -69,11 +69,10 @@ pub fn run() {
                             break;
                         }
                         let (station, temp) = line.rsplit_once(|&byte| byte == b';').unwrap();
-                        let hash = hashstr(station);
                         let station = unsafe { String::from_utf8_unchecked(Vec::from(station)) };
                         let temp = parse::temp(temp.split_last().unwrap().1);
-                        let measurements_option = t_stations.get_mut(&hash);
-                        if let Some((_, measurements)) = measurements_option {
+                        let measurements_option = t_stations.get_mut(&station);
+                        if let Some(measurements) = measurements_option {
                             measurements.update(temp);
                         } else {
                             let measurements = StationMeasurements {
@@ -82,7 +81,7 @@ pub fn run() {
                                 count: 1,
                                 sum: temp,
                             };
-                            t_stations.insert(hash, (station, measurements));
+                            t_stations.insert(station, measurements);
                         }
                         currposition += line_len as u64;
                         if currposition >= end {
@@ -96,18 +95,18 @@ pub fn run() {
         }
         drop(tx);
         while let Ok(t_stations) = rx.recv() {
-            for (&hash, (station, measurements)) in t_stations.iter() {
-                let joined_measurements_options = stations.get_mut(&hash);
-                if let Some((_, joined_measurements)) = joined_measurements_options {
+            for (station, measurements) in t_stations.iter() {
+                let joined_measurements_options = stations.get_mut(station);
+                if let Some(joined_measurements) = joined_measurements_options {
                     joined_measurements.merge(measurements);
                 } else {
-                    stations.insert(hash, (station.to_owned(), *measurements));
+                    stations.insert(station.to_owned(), *measurements);
                 }
             }
         }
         let mut stations: Vec<String> = stations
             .iter()
-            .map(|(_, (station, measurements))| {
+            .map(|(station, measurements)| {
                 let measurements = measurements.to_string();
                 #[cfg(feature = "json")]
                 {