From 36a6140ca9b9b304587a1fe96270df395027d4b8 Mon Sep 17 00:00:00 2001
From: mykola2312 <49044616+mykola2312@users.noreply.github.com>
Date: Tue, 29 Aug 2023 23:08:04 +0300
Subject: [PATCH] implement ReadStream

---
 src/fot.rs        |  7 ++++---
 src/fot/stream.rs | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 3 deletions(-)
 create mode 100644 src/fot/stream.rs

diff --git a/src/fot.rs b/src/fot.rs
index 8ae5475..60cdb9a 100644
--- a/src/fot.rs
+++ b/src/fot.rs
@@ -1,6 +1,7 @@
-mod raw;
 mod decoder;
-mod tag;
 mod fstring;
+mod raw;
+pub mod save;
+mod stream;
+mod tag;
 mod world;
-pub mod save;
\ No newline at end of file
diff --git a/src/fot/stream.rs b/src/fot/stream.rs
new file mode 100644
index 0000000..91aecba
--- /dev/null
+++ b/src/fot/stream.rs
@@ -0,0 +1,41 @@
+use super::decoder::Decoder;
+use super::raw::Raw;
+use anyhow::Result;
+use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
+use std::io::Cursor;
+
+pub struct ReadStream<'a> {
+    raw: &'a Raw,
+    rdr: Cursor<&'a [u8]>,
+}
+
+impl<'a> ReadStream<'a> {
+    fn new(raw: &Raw, offset: usize) -> ReadStream {
+        ReadStream {
+            raw: raw,
+            rdr: Cursor::new(&raw.mem[offset..]),
+        }
+    }
+
+    fn offset(&self) -> usize {
+        self.rdr.position() as usize
+    }
+
+    fn skip(&mut self, size: usize) {
+        self.rdr.set_position(self.rdr.position() + size as u64);
+    }
+
+    fn read<T: Decoder>(&mut self, size: usize) -> Result<T> {
+        let val = T::decode(&self.raw, self.offset(), size)?;
+        self.skip(val.get_enc_size());
+        Ok(val)
+    }
+
+    fn read_u16(&mut self) -> Result<u16> {
+        Ok(self.rdr.read_u16::<LittleEndian>()?)
+    }
+
+    fn read_u32(&mut self) -> Result<u32> {
+        Ok(self.rdr.read_u32::<LittleEndian>()?)
+    }
+}