From 06c7cafe7fd3875d4af497d100de527681233241 Mon Sep 17 00:00:00 2001
From: RockerBot <rockerbotmail@gmail.com>
Date: Sat, 22 Oct 2022 01:35:09 +0530
Subject: [PATCH] chunked file input

followed same documentation
---
 src/algorithms.rs | 38 ++++++++++++++++++++++++++++++++------
 1 file changed, 32 insertions(+), 6 deletions(-)

diff --git a/src/algorithms.rs b/src/algorithms.rs
index 52b95e9..b7eeee0 100644
--- a/src/algorithms.rs
+++ b/src/algorithms.rs
@@ -1,16 +1,42 @@
-use md5;
-use sha2::{Digest, Sha256};
+use md5::Context;
+use sha2::{Digest as shaDigest, Sha256};
+use std::io::{ prelude::*, BufReader};
 
 pub fn calc_sha256(filepath: &str) -> String {
-    let file_as_bytes = std::fs::read(filepath).unwrap();
-    let hash = Sha256::digest(file_as_bytes);
+    // breaks file into lines and cumulatively calculates the hash
+    let file = std::fs::File::open(filepath).unwrap();
+    let reader = BufReader::new(file);
+
+    let mut hasher = Sha256::new();
+    for line in reader.lines(){
+        match line {
+            Ok(a) => {
+                hasher.update(a.as_bytes());
+                hasher.update(b"\n");
+            },
+            _ => break,
+        };
+    }
+    let hash = hasher.finalize();
 
     format!("{:x}", hash)
 }
 
 pub fn calc_md5(filepath: &str) -> String {
-    let file_as_bytes = std::fs::read(filepath).unwrap();
-    let hash = md5::compute(file_as_bytes);
+    let file = std::fs::File::open(filepath).unwrap();
+    let reader = BufReader::new(file);
+
 
+    let mut hasher = Context::new();
+    for line in reader.lines(){
+        match line {
+            Ok(a) => {
+                hasher.consume(a.as_bytes());
+                hasher.consume(b"\n");
+            },
+            _ => break,
+        };
+    }
+    let hash = hasher.compute();
     format!("{:x}", hash)
 }