Load FST using memory-mapped file

Signed-off-by: Keshav Priyadarshi <[email protected]>

Author: keshav-space

Cargo.lock

@@ -23,6 +23,7 @@ crate-type = ["rlib"]
 
 [dependencies]
 fst = "0.4.7"
+memmap2 = "0.9.9"
 once_cell = "1.21"
 
 [[bin]]

Cargo.toml

@@ -1,10 +1,16 @@
 use fst::Set;
+use memmap2::Mmap;
 use once_cell::sync::Lazy;
+use std::env;
+use std::fs::File;
+use std::path::Path;
 
-static FST_BYTES: &[u8] = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/purls.fst"));
-
-static VALIDATOR: Lazy<Set<&[u8]>> =
-    Lazy::new(|| Set::new(FST_BYTES).expect("Failed to load FST from embedded bytes"));
+static VALIDATOR: Lazy<Set<Mmap>> = Lazy::new(|| {
+    let path = Path::new(env!("CARGO_MANIFEST_DIR")).join("purls.fst");
+    let file = File::open(path).expect("Failed to open FST file");
+    let mmap = unsafe { Mmap::map(&file).expect("Failed to mmap FST file") };
+    Set::new(mmap).expect("Failed to load FST from mmap")
+});
 
 pub fn validate(packageurl: &str) -> bool {
     let trimmed_packageurl = packageurl.trim_end_matches("/");