From d7236f05a9891a8a750b52f588724b6d0e877bfc Mon Sep 17 00:00:00 2001
From: Igor Katson <igor.katson@gmail.com>
Date: Tue, 20 Aug 2024 15:07:23 +0100
Subject: [PATCH] Add bitv module

---
 crates/librqbit/src/bitv.rs | 78 +++++++++++++++++++++++++++++++++++++
 crates/librqbit/src/lib.rs  |  1 +
 2 files changed, 79 insertions(+)
 create mode 100644 crates/librqbit/src/bitv.rs

diff --git a/crates/librqbit/src/bitv.rs b/crates/librqbit/src/bitv.rs
new file mode 100644
index 0000000..47c9cc8
--- /dev/null
+++ b/crates/librqbit/src/bitv.rs
@@ -0,0 +1,78 @@
+use std::fs::File;
+
+use anyhow::Context;
+use bitvec::{order::Lsb0, slice::BitSlice, vec::BitVec, view::AsBits, view::AsMutBits};
+
+pub trait BitV: Send {
+    fn as_slice(&self) -> &BitSlice<u8, Lsb0>;
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0>;
+    fn flush(&mut self) -> anyhow::Result<()>;
+    fn into_dyn(self) -> Box<dyn BitV>;
+}
+
+pub struct MmapBitV {
+    _file: File,
+    mmap: memmap2::MmapMut,
+}
+
+impl MmapBitV {
+    pub fn new(file: File) -> anyhow::Result<Self> {
+        let mmap =
+            unsafe { memmap2::MmapOptions::new().map_mut(&file) }.context("error mmapping file")?;
+        Ok(Self { mmap, _file: file })
+    }
+}
+
+impl BitV for BitVec<u8, Lsb0> {
+    fn as_slice(&self) -> &BitSlice<u8, Lsb0> {
+        self.as_bitslice()
+    }
+
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0> {
+        self.as_mut_bitslice()
+    }
+
+    fn flush(&mut self) -> anyhow::Result<()> {
+        Ok(())
+    }
+
+    fn into_dyn(self) -> Box<dyn BitV> {
+        Box::new(self)
+    }
+}
+
+impl BitV for MmapBitV {
+    fn as_slice(&self) -> &BitSlice<u8, Lsb0> {
+        self.mmap.as_bits()
+    }
+
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0> {
+        self.mmap.as_mut_bits()
+    }
+
+    fn flush(&mut self) -> anyhow::Result<()> {
+        Ok(self.mmap.flush()?)
+    }
+
+    fn into_dyn(self) -> Box<dyn BitV> {
+        Box::new(self)
+    }
+}
+
+impl BitV for Box<dyn BitV> {
+    fn as_slice(&self) -> &BitSlice<u8, Lsb0> {
+        (**self).as_slice()
+    }
+
+    fn as_slice_mut(&mut self) -> &mut BitSlice<u8, Lsb0> {
+        (**self).as_slice_mut()
+    }
+
+    fn flush(&mut self) -> anyhow::Result<()> {
+        (**self).flush()
+    }
+
+    fn into_dyn(self) -> Box<dyn BitV> {
+        self
+    }
+}
diff --git a/crates/librqbit/src/lib.rs b/crates/librqbit/src/lib.rs
index 16ea5be..b23e2dd 100644
--- a/crates/librqbit/src/lib.rs
+++ b/crates/librqbit/src/lib.rs
@@ -40,6 +40,7 @@ macro_rules! aframe {
 
 pub mod api;
 mod api_error;
+mod bitv;
 mod chunk_tracker;
 mod create_torrent_file;
 mod dht_utils;