diff --git a/.gitignore b/.gitignore
index aec297f..56512f7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 /target
 prod
+tarpaulin-report.html
diff --git a/Cargo.lock b/Cargo.lock
index 3863fda..3ce1f9a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -17,6 +17,7 @@ dependencies = [
  "derive_builder",
  "mime",
  "mime_guess",
+ "serde",
  "sha2",
  "walkdir",
 ]
@@ -186,6 +187,12 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "serde"
+version = "1.0.125"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "558dc50e1a5a5fa7112ca2ce4effcb321b0300c0d4ccf0776a9f60cd89031171"
+
 [[package]]
 name = "sha2"
 version = "0.9.3"
diff --git a/Cargo.toml b/Cargo.toml
index 73f2cea..c16f6b0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,3 +18,4 @@ sha2 = "0.9.3"
 derive_builder = "0.10.0"
 data-encoding = "2.3.2"
 walkdir = "2"
+serde = "1.0.125"
diff --git a/src/hash.rs b/src/hash.rs
index 49fe8f5..d81c2b5 100644
--- a/src/hash.rs
+++ b/src/hash.rs
@@ -5,7 +5,6 @@
 * License.
 */
 
-use std::collections::HashMap;
 use std::io::Error;
 use std::path::Path;
 use std::{fs, path::PathBuf};
@@ -13,6 +12,8 @@ use std::{fs, path::PathBuf};
 use derive_builder::Builder;
 use walkdir::WalkDir;
 
+use crate::map::Files;
+
 #[derive(Debug, Clone, Builder)]
 pub struct Buster {
     // source directory
@@ -52,8 +53,8 @@ impl Buster {
     // use [hash] when when they aren't
     //
     // doesn't process files for which mime is not resolved
-    pub fn try_hash(&self) -> Result<HashMap<String, String>, Error> {
-        let mut file_map: HashMap<String, String> = HashMap::default();
+    pub fn try_hash(&self) -> Result<Files, Error> {
+        let mut file_map: Files = Files::default();
         for entry in WalkDir::new(&self.source)
             .follow_links(self.follow_links)
             .into_iter()
@@ -76,10 +77,12 @@ impl Buster {
                         self.copy(path, &new_name);
 
                         let (source, destination) = self.gen_map(path, &&new_name);
-                        file_map.insert(
-                            source.to_str().unwrap().into(),
-                            destination.to_str().unwrap().into(),
-                        );
+                        file_map
+                            .add(
+                                source.to_str().unwrap().into(),
+                                destination.to_str().unwrap().into(),
+                            )
+                            .unwrap();
                     }
                 }
             }
@@ -90,8 +93,8 @@ impl Buster {
 
     // panics when mimetypes are detected. This way you'll know which files are ignored
     // from processing
-    pub fn hash(&self) -> Result<HashMap<String, String>, Error> {
-        let mut file_map: HashMap<String, String> = HashMap::default();
+    pub fn hash(&self) -> Result<Files, Error> {
+        let mut file_map: Files = Files::default();
 
         for entry in WalkDir::new(&self.source)
             .follow_links(self.follow_links)
@@ -118,10 +121,12 @@ impl Buster {
                         );
                         self.copy(path, &new_name);
                         let (source, destination) = self.gen_map(path, &&new_name);
-                        file_map.insert(
-                            source.to_str().unwrap().into(),
-                            destination.to_str().unwrap().into(),
-                        );
+                        file_map
+                            .add(
+                                source.to_str().unwrap().into(),
+                                destination.to_str().unwrap().into(),
+                            )
+                            .unwrap();
                     }
                 }
             }
@@ -205,9 +210,9 @@ mod tests {
             .unwrap();
 
         config.init().unwrap();
-        let mut map = config.hash().unwrap();
+        let mut files = config.hash().unwrap();
 
-        for (k, v) in map.drain() {
+        for (k, v) in files.map.drain() {
             let src = Path::new(&k);
             let dest = Path::new(&v);
 
@@ -234,9 +239,9 @@ mod tests {
             .unwrap();
 
         config.init().unwrap();
-        let mut map = config.hash().unwrap();
+        let mut files = config.try_hash().unwrap();
 
-        for (k, v) in map.drain() {
+        for (k, v) in files.map.drain() {
             let src = Path::new(&k);
             let dest = Path::new(&v);
 
diff --git a/src/lib.rs b/src/lib.rs
index 8a8ee45..86b1d72 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,4 +33,6 @@
 //! ```
 
 pub mod hash;
+pub mod map;
 pub use hash::BusterBuilder;
+pub use map::Files;
diff --git a/src/map.rs b/src/map.rs
new file mode 100644
index 0000000..c08b2bb
--- /dev/null
+++ b/src/map.rs
@@ -0,0 +1,76 @@
+/*
+* Copyright (C) 2021  Aravinth Manivannan <realaravinth@batsense.net>
+*
+* Use of this source code is governed by the Apache 2.0 and/or the MIT
+* License.
+*/
+
+use std::collections::HashMap;
+
+#[derive(Debug, Default, Clone)]
+pub struct Files {
+    pub map: HashMap<String, String>,
+    base_dir: String,
+}
+
+impl Files {
+    pub fn get<'a>(&'a self, path: &'a str) -> Option<&'a String> {
+        self.map.get(path)
+    }
+
+    pub fn add(&mut self, k: String, v: String) -> Result<(), &'static str> {
+        if self.map.contains_key(&k) {
+            Err("key exists")
+        } else {
+            self.map.insert(k, v);
+            Ok(())
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::hash::*;
+
+    use super::*;
+    use std::path::Path;
+
+    #[test]
+    fn get_works() {
+        let types = vec![
+            mime::IMAGE_PNG,
+            mime::IMAGE_SVG,
+            mime::IMAGE_JPEG,
+            mime::IMAGE_GIF,
+        ];
+
+        let config = BusterBuilder::default()
+            .source("./dist")
+            .result("/tmp/prod2")
+            .mime_types(types)
+            .copy(true)
+            .follow_links(true)
+            .build()
+            .unwrap();
+
+        config.init().unwrap();
+        let files = config.hash().unwrap();
+
+        assert!(file_exists("./dist/log-out.svg", &files));
+        assert!(file_exists(
+            "./dist/a/b/c/d/s/d/svg/credit-card.svg",
+            &files
+        ));
+
+        assert!(!file_exists("dist/log-out.svg", &files));
+        assert!(!file_exists("dist/a/b/c/d/s/d/svg/credit-card.svg", &files));
+    }
+
+    fn file_exists(path: &str, files: &Files) -> bool {
+        if let Some(file) = files.get(path) {
+            Path::new(file).exists()
+        } else {
+            false
+        }
+    }
+}