diff options
Diffstat (limited to 'src/types.rs')
| -rw-r--r-- | src/types.rs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/src/types.rs b/src/types.rs index 563f353..842635c 100644 --- a/src/types.rs +++ b/src/types.rs @@ -1,11 +1,17 @@ // Copyright 2021 Colin Finck <colin@reactos.org> // SPDX-License-Identifier: GPL-2.0-or-later +// +//! Supplementary helper types. use crate::error::{NtfsError, Result}; use crate::ntfs::Ntfs; use binread::BinRead; use derive_more::{Binary, Display, From, LowerHex, Octal, UpperHex}; +/// A Logical Cluster Number (LCN). +/// +/// NTFS divides a filesystem into clusters of a given size (power of two), see [`Ntfs::cluster_size`]. +/// The LCN is an absolute cluster index into the filesystem. #[derive( Binary, BinRead, @@ -25,6 +31,7 @@ use derive_more::{Binary, Display, From, LowerHex, Octal, UpperHex}; pub struct Lcn(u64); impl Lcn { + /// Performs a checked addition of the given Virtual Cluster Number (VCN), returning a new 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) @@ -35,6 +42,7 @@ impl Lcn { } } + /// Returns the absolute byte position of this LCN within the filesystem. pub fn position(&self, ntfs: &Ntfs) -> Result<u64> { self.0 .checked_mul(ntfs.cluster_size() as u64) @@ -42,6 +50,11 @@ impl Lcn { } } +/// A Virtual Cluster Number (VCN). +/// +/// NTFS divides a filesystem into clusters of a given size (power of two), see [`Ntfs::cluster_size`]. +/// The VCN is a cluster index into the filesystem that is relative to a Logical Cluster Number (LCN) +/// or relative to the start of an attribute value. #[derive( Binary, BinRead, @@ -61,6 +74,7 @@ impl Lcn { pub struct Vcn(i64); impl Vcn { + /// Converts this VCN into a byte offset (with respect to the cluster size of the provided [`Ntfs`] filesystem). pub fn offset(&self, ntfs: &Ntfs) -> Result<i64> { self.0 .checked_mul(ntfs.cluster_size() as i64) |