fix: buffer alloc and measure header size

crates/league-modpkg/src/lib.rs

@@ -4,6 +4,7 @@ use std::collections::HashMap;
 
 mod chunk;
 mod error;
+mod pkg_utils;
 mod read;
 
 #[derive(Debug, PartialEq)]

crates/league-modpkg/src/pkg_utils.rs

@@ -0,0 +1,3 @@
+impl Modpkg {
+    pub fn get
+}

crates/league-modpkg/src/read.rs

@@ -1,5 +1,6 @@
 use crate::{error::ModpkgError, Modpkg, ModpkgChunk, ModpkgMetadata};
 use byteorder::{ReadBytesExt as _, LE};
+use io_ext::measure;
 use std::{
     collections::{hash_map::Entry, HashMap},
     io::{BufReader, Read, Seek, SeekFrom},
@@ -9,37 +10,59 @@ impl Modpkg {
     pub const MAGIC: u64 = u64::from_le_bytes(*b"_modpkg_");
 
     pub fn read(reader: &mut BufReader<impl Read + Seek>) -> Result<Self, ModpkgError> {
-        let magic = reader.read_u64::<LE>()?;
-        if magic != Self::MAGIC {
-            return Err(ModpkgError::InvalidMagic(magic));
-        }
+        let (
+            real_header_size,
+            (
+                header_size,
+                metadata_size,
+                signature_size,
+                chunk_paths_size,
+                wad_paths_size,
+                layers_size,
+                chunk_count,
+            ),
+        ) = measure(reader, |reader| {
+            let magic = reader.read_u64::<LE>()?;
+            if magic != Self::MAGIC {
+                return Err(ModpkgError::InvalidMagic(magic));
+            }
 
-        let version = reader.read_u32::<LE>()?;
-        if version != 1 {
-            return Err(ModpkgError::InvalidVersion(version));
-        }
+            let version = reader.read_u32::<LE>()?;
+            if version != 1 {
+                return Err(ModpkgError::InvalidVersion(version));
+            }
 
-        let header_size = reader.read_u32::<LE>()?;
-        let metadata_size = reader.read_u32::<LE>()? as usize;
-        let signature_size = reader.read_u32::<LE>()? as usize;
-        let chunk_paths_size = reader.read_u32::<LE>()? as usize;
-        let wad_paths_size = reader.read_u32::<LE>()? as usize;
-        let layers_size = reader.read_u32::<LE>()? as usize;
-        let chunk_count = reader.read_u32::<LE>()?;
+            let header_size = reader.read_u32::<LE>()?;
+            let metadata_size = reader.read_u32::<LE>()? as usize;
+            let signature_size = reader.read_u32::<LE>()? as usize;
+            let chunk_paths_size = reader.read_u32::<LE>()? as usize;
+            let wad_paths_size = reader.read_u32::<LE>()? as usize;
+            let layers_size = reader.read_u32::<LE>()? as usize;
+            let chunk_count = reader.read_u32::<LE>()?;
 
-        let current_pos = reader.seek(SeekFrom::Current(0))?;
-        if header_size != current_pos as u32 {
+            Ok((
+                header_size,
+                metadata_size,
+                signature_size,
+                chunk_paths_size,
+                wad_paths_size,
+                layers_size,
+                chunk_count,
+            ))
+        })?;
+
+        if header_size != real_header_size as u32 {
             return Err(ModpkgError::InvalidHeaderSize {
                 header_size,
-                actual_size: current_pos,
+                actual_size: real_header_size,
             });
         }
 
-        let mut metadata = Vec::with_capacity(metadata_size);
-        let mut signature = Vec::with_capacity(signature_size);
-        let mut chunk_paths = Vec::with_capacity(chunk_paths_size);
-        let mut wad_paths = Vec::with_capacity(wad_paths_size);
-        let mut layers = Vec::with_capacity(layers_size);
+        let mut metadata = vec![0; metadata_size];
+        let mut signature = vec![0; signature_size];
+        let mut chunk_paths = vec![0; chunk_paths_size];
+        let mut wad_paths = vec![0; wad_paths_size];
+        let mut layers = vec![0; layers_size];
 
         reader.read_exact(&mut metadata)?;
         reader.read_exact(&mut signature)?;