1 files changed, 63 insertions, 0 deletions
diff --git a/src/types.rs b/src/types.rs
new file mode 100644
index 0000000..d327484
--- /dev/null
+++ b/src/types.rs
@@ -0,0 +1,63 @@
+// Copyright 2021 Colin Finck <colin@reactos.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use crate::error::{NtfsError, Result};
+use crate::ntfs::Ntfs;
+use binread::BinRead;
+use core::fmt;
+
+#[derive(BinRead, Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub struct Lcn(u64);
+
+impl Lcn {
+    pub fn checked_add(&self, vcn: Vcn) -> Option<Lcn> {
+        if vcn.0 >= 0 {
+            self.0.checked_add(vcn.0 as u64).map(Into::into)
+        } else {
+            self.0
+                .checked_sub(vcn.0.wrapping_neg() as u64)
+                .map(Into::into)
+        }
+    }
+
+    pub fn position(&self, ntfs: &Ntfs) -> Result<u64> {
+        self.0
+            .checked_mul(ntfs.cluster_size() as u64)
+            .ok_or(NtfsError::LcnTooBig { lcn: *self })
+    }
+}
+
+impl fmt::Display for Lcn {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+impl From<u64> for Lcn {
+    fn from(value: u64) -> Self {
+        Self(value)
+    }
+}
+
+#[derive(BinRead, Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub struct Vcn(i64);
+
+impl Vcn {
+    pub fn offset(&self, ntfs: &Ntfs) -> Result<i64> {
+        self.0
+            .checked_mul(ntfs.cluster_size() as i64)
+            .ok_or(NtfsError::VcnTooBig { vcn: *self })
+    }
+}
+
+impl fmt::Display for Vcn {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+impl From<i64> for Vcn {
+    fn from(value: i64) -> Self {
+        Self(value)
+    }
+}