commit 6fd1293e4aab31a3ff06230f2b23a8008186583f
Author: trivernis <trivernis@protonmail.com>
Date:   Fri Sep 25 19:21:11 2020 +0200

    Add subcommand to get the number of chunks inside a world folder
    
    Signed-off-by: trivernis <trivernis@protonmail.com>

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diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..f9a4f2a
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "minecraft-regions-tool"
+version = "0.1.0"
+authors = ["trivernis <trivernis@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+byteorder = "1.3.4"
+structopt = "0.3.18"
+scheduled-thread-pool = "0.2.5"
+num_cpus = "1.13.0"
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..10883dc
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,2 @@
+pub mod region_file;
+pub mod world_folder;
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..8d3af3d
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,28 @@
+use minecraft_regions_tool::world_folder::WorldFolder;
+use std::path::PathBuf;
+use structopt::StructOpt;
+
+#[derive(StructOpt, Debug)]
+struct Opt {
+    /// Path to the world folder
+    #[structopt(parse(from_os_str))]
+    input: PathBuf,
+
+    #[structopt(subcommand)]
+    sub_command: SubCommand,
+}
+
+#[derive(StructOpt, Debug)]
+#[structopt()]
+enum SubCommand {
+    /// Return the total number of chunks in the world
+    Count,
+}
+
+fn main() {
+    let opt: Opt = Opt::from_args();
+    let world = WorldFolder::new(opt.input);
+    match opt.sub_command {
+        SubCommand::Count => println!("Chunk Count: {}", world.count_chunks().unwrap()),
+    }
+}
diff --git a/src/region_file.rs b/src/region_file.rs
new file mode 100644
index 0000000..e473668
--- /dev/null
+++ b/src/region_file.rs
@@ -0,0 +1,91 @@
+use byteorder::{BigEndian, ByteOrder};
+use std::io::{Read, Result};
+
+const BLOCK_SIZE: usize = 4096;
+
+pub struct RegionFile {
+    reader: Box<dyn Read>,
+    locations: Locations,
+    timestamps: Timestamps,
+}
+
+impl RegionFile {
+    pub fn new(reader: Box<dyn Read>) -> Result<Self> {
+        let mut locations_raw = [0u8; BLOCK_SIZE];
+        let mut timestamps_raw = [0u8; BLOCK_SIZE];
+        let mut reader = reader;
+        reader.read_exact(&mut locations_raw)?;
+        reader.read_exact(&mut timestamps_raw)?;
+
+        Ok(Self {
+            locations: Locations::from_bytes(&locations_raw),
+            timestamps: Timestamps::from_bytes(&timestamps_raw),
+            reader,
+        })
+    }
+
+    /// Returns the number of chunks in the file
+    pub fn count_chunks(&self) -> usize {
+        let mut count = 0;
+        for x in 0..32 {
+            for z in 0..32 {
+                if !(self.locations.get_chunk_offset(x, z) == Some(0)
+                    && self.locations.get_chunk_sectors(x, z) == Some(0))
+                {
+                    count += 1;
+                }
+            }
+        }
+
+        return count;
+    }
+}
+
+#[derive(Debug)]
+pub struct Locations {
+    inner: Vec<(u32, u8)>,
+}
+
+impl Locations {
+    pub fn from_bytes(bytes: &[u8; BLOCK_SIZE]) -> Self {
+        let mut locations = Vec::new();
+
+        for i in (0..BLOCK_SIZE - 1).step_by(4) {
+            let mut offset = BigEndian::read_u32(&bytes[i..i + 4]);
+            offset = offset >> 1;
+            let count = bytes[i + 3];
+            locations.push((offset, count));
+        }
+
+        Self { inner: locations }
+    }
+
+    /// Returns the offset of a chunk
+    pub fn get_chunk_offset(&self, x: usize, z: usize) -> Option<u32> {
+        let index = x % 32 + (z % 32) * 32;
+        self.inner.get(index).map(|e| (*e).0)
+    }
+
+    /// Returns the number of sectors for a chunk
+    pub fn get_chunk_sectors(&self, x: usize, z: usize) -> Option<u8> {
+        let index = x % 32 + (z % 32) * 32;
+        self.inner.get(index).map(|e| (*e).1)
+    }
+}
+
+#[derive(Debug)]
+pub struct Timestamps {
+    inner: Vec<u32>,
+}
+
+impl Timestamps {
+    pub fn from_bytes(bytes: &[u8; BLOCK_SIZE]) -> Self {
+        let mut timestamps = Vec::new();
+
+        for i in (0..BLOCK_SIZE - 1).step_by(4) {
+            timestamps.push(BigEndian::read_u32(&bytes[i..i + 4]))
+        }
+
+        Self { inner: timestamps }
+    }
+}
diff --git a/src/world_folder.rs b/src/world_folder.rs
new file mode 100644
index 0000000..bdbf964
--- /dev/null
+++ b/src/world_folder.rs
@@ -0,0 +1,33 @@
+use crate::region_file::RegionFile;
+use std::ffi::OsStr;
+use std::fs;
+use std::fs::File;
+use std::io;
+use std::io::BufReader;
+use std::path::PathBuf;
+
+pub struct WorldFolder {
+    path: PathBuf,
+}
+
+impl WorldFolder {
+    pub fn new(path: PathBuf) -> Self {
+        Self { path }
+    }
+
+    pub fn count_chunks(&self) -> io::Result<u64> {
+        let mut count = 0u64;
+        let region_file_path = self.path.join(PathBuf::from("region"));
+
+        for file in fs::read_dir(region_file_path)? {
+            let file_path = file?.path();
+            if file_path.extension() == Some(OsStr::new("mca")) {
+                let f = File::open(file_path)?;
+                let region_file = RegionFile::new(Box::new(BufReader::new(f)))?;
+                count += region_file.count_chunks() as u64;
+            }
+        }
+
+        Ok(count)
+    }
+}