Added ability to read WAD directory

src/lib.rs

@@ -0,0 +1,8 @@
+#[cfg(test)]
+mod tests;
+
+mod lumps;
+mod utils;
+mod wad;
+
+pub use wad::WADFile;

src/tests/helpers.rs

@@ -0,0 +1,15 @@
+use crate::utils::*;
+
+#[test]
+pub fn valid_wad() {
+    let wad_path = String::from("WADs/doom1.wad");
+
+    assert!(validate_wad(wad_path.as_str()).unwrap_or(false));
+}
+
+#[test]
+pub fn wad_path_invalid() {
+    let wad_path = String::from("WADs/invalid.wad");
+
+    assert!(!validate_wad(wad_path.as_str()).unwrap_or(false));
+}

src/tests/mod.rs

@@ -0,0 +1,5 @@
+#[cfg(test)]
+mod wad;
+
+#[cfg(test)]
+mod helpers;

src/tests/wad.rs

@@ -0,0 +1,36 @@
+use crate::WADFile;
+
+#[test]
+pub fn successful_wad_id() {
+    let wad_file = WADFile::new(String::from("WADs/doom1.wad"));
+
+    assert_eq!(wad_file.wad_id, "IWAD");
+}
+
+#[test]
+pub fn correct_lumps() {
+    let wad_file = WADFile::new(String::from("WADs/doom1.wad"));
+
+    assert_eq!(wad_file.num_lumps, 1264);
+}
+
+#[test]
+pub fn correct_dir_size() {
+    let wad_file = WADFile::new(String::from("WADs/doom1.wad"));
+
+    assert_eq!(wad_file.directory.len(), 1264);
+}
+
+#[test]
+pub fn correct_lump_name() {
+    let wad_file = WADFile::new(String::from("WADs/doom1.wad"));
+
+    assert_eq!(wad_file.directory[0].name, "PLAYPAL");
+}
+
+#[test]
+pub fn read_level_lump() {
+    let wad_file = WADFile::new(String::from("WADs/doom1.wad"));
+
+    assert_eq!(wad_file.directory[6].name, "E1M1");
+}

src/utils/helpers.rs

@@ -0,0 +1,43 @@
+use std::{
+    fs::File,
+    io::{self, Read},
+    path::Path,
+};
+
+/// Validates a WAD file to make sure that it is a legitimate file
+///
+/// Parameters:
+/// - path: &str - Path to the WAD to validate
+pub fn validate_wad(path: &str) -> io::Result<bool> {
+    let wad_file = Path::new(path);
+
+    // Check to see if the WAD exists
+    if !(wad_file.exists()) {
+        // Return back false because we didn't pass a valid file
+        return Ok(false);
+    }
+
+    // If the file exists open it and read the first 4 bytes
+    // of the file and see if we get "IWAD" or "PWAD"
+    let mut file = File::open(wad_file)?;
+    let mut magic = [0u8; 4];
+    file.read_exact(&mut magic)?;
+
+    // Now we return based on what we found
+    Ok(magic == *b"IWAD" || magic == *b"PWAD")
+}
+
+pub fn read_ascii(bytes: &[u8]) -> String {
+    std::str::from_utf8(&bytes[..bytes.len()])
+        .unwrap_or("")
+        .trim_end_matches('\0')
+        .to_string()
+}
+
+pub fn read_u32_le(bytes: &[u8]) -> u32 {
+    if bytes.len() < 4 {
+        0
+    } else {
+        u32::from_le_bytes(bytes[..4].try_into().unwrap())
+    }
+}

src/utils/mod.rs

@@ -0,0 +1,6 @@
+mod error;
+mod helpers;
+
+pub use helpers::read_ascii;
+pub use helpers::read_u32_le;
+pub use helpers::validate_wad;

src/wad/directory.rs

@@ -0,0 +1,5 @@
+pub struct Directory {
+    pub filepos: u32,
+    pub size: u32,
+    pub name: String,
+}

src/wad/header.rs

@@ -0,0 +1,21 @@
+pub struct Header {
+    pub wad_id: String,
+    pub num_lumps: u32,
+    pub dir_offset: u32,
+}
+
+use crate::utils::{read_ascii, read_u32_le};
+
+impl Header {
+    pub fn read_data(data: &[u8]) -> Self {
+        let id = read_ascii(&data[..4]);
+        let lumps = read_u32_le(&data[4..8]);
+        let offset = read_u32_le(&data[8..12]);
+
+        Self {
+            wad_id: id,
+            num_lumps: lumps,
+            dir_offset: offset,
+        }
+    }
+}

src/wad/mod.rs

@@ -0,0 +1,5 @@
+mod directory;
+mod header;
+mod wadfile;
+
+pub use wadfile::WADFile;

src/wad/wadfile.rs

@@ -0,0 +1,54 @@
+use std::{fs::File, io::Read, path::Path};
+
+use super::{directory::Directory, header::Header};
+use crate::utils::{read_ascii, read_u32_le, validate_wad};
+
+pub struct WADFile {
+    pub path: String,
+    pub wad_id: String,
+    pub num_lumps: u32,
+    pub dir_offset: u32,
+    pub directory: Vec<Directory>,
+    pub wad_data: Vec<u8>,
+}
+
+impl WADFile {
+    pub fn new(path: String) -> Self {
+        if !(validate_wad(path.as_str()).unwrap()) {
+            panic!();
+        }
+
+        let file_path = Path::new(path.as_str());
+        let mut wad_file = File::open(file_path).unwrap();
+        let file_size = wad_file.metadata().unwrap().len() as usize;
+        let mut file_buffer: Vec<u8> = Vec::with_capacity(file_size);
+
+        wad_file.read_to_end(&mut file_buffer).unwrap();
+
+        let wad_header = Header::read_data(&file_buffer[0..12]);
+
+        let mut wad_dir: Vec<Directory> = Vec::with_capacity(wad_header.num_lumps as usize);
+        let offset = wad_header.dir_offset;
+
+        for entry in 0..wad_header.num_lumps {
+            let startpos = (offset + 16 * entry) as usize;
+            let filepos = read_u32_le(&file_buffer[startpos..startpos + 4]);
+            let size = read_u32_le(&file_buffer[startpos + 4..startpos + 8]);
+            let name = read_ascii(&file_buffer[startpos + 8..startpos + 16]);
+            wad_dir.push(Directory {
+                filepos,
+                name,
+                size,
+            });
+        }
+
+        Self {
+            path,
+            wad_id: wad_header.wad_id,
+            num_lumps: wad_header.num_lumps,
+            dir_offset: wad_header.dir_offset,
+            directory: wad_dir,
+            wad_data: file_buffer,
+        }
+    }
+}