Implement `NtfsVolumeInformation` and `NtfsVolumeName` structured values

1 files changed, 81 insertions, 0 deletions

diff --git a/src/structured_values/volume_name.rs b/src/structured_values/volume_name.rs
index 53769a7..72bd3bc 100644
--- a/src/structured_values/volume_name.rs
+++ b/src/structured_values/volume_name.rs
@@ -1,2 +1,83 @@
 // Copyright 2021 Colin Finck <colin@reactos.org>
 // SPDX-License-Identifier: GPL-2.0-or-later
+
+use crate::attribute::NtfsAttributeType;
+use crate::attribute_value::NtfsAttributeValueAttached;
+use crate::error::{NtfsError, Result};
+use crate::string::NtfsString;
+use binread::io::{Read, Seek, SeekFrom};
+use core::mem;
+
+/// The smallest VolumeName attribute has a name containing just a single character.
+const VOLUME_NAME_MIN_SIZE: u64 = mem::size_of::<u16>() as u64;
+
+/// The largest VolumeName attribute has a name containing 128 UTF-16 code points (256 bytes).
+const VOLUME_NAME_MAX_SIZE: u64 = 128 * mem::size_of::<u16>() as u64;
+
+#[derive(Clone, Debug)]
+pub struct NtfsVolumeName {
+    name_position: u64,
+    name_length: u16,
+}
+
+impl NtfsVolumeName {
+    pub(crate) fn new<T>(
+        attribute_position: u64,
+        value_attached: NtfsAttributeValueAttached<'_, T>,
+        value_length: u64,
+    ) -> Result<Self>
+    where
+        T: Read + Seek,
+    {
+        if value_length < VOLUME_NAME_MIN_SIZE {
+            return Err(NtfsError::InvalidAttributeSize {
+                position: attribute_position,
+                ty: NtfsAttributeType::VolumeName,
+                expected: VOLUME_NAME_MIN_SIZE,
+                actual: value_length,
+            });
+        } else if value_length > VOLUME_NAME_MAX_SIZE {
+            return Err(NtfsError::InvalidAttributeSize {
+                position: attribute_position,
+                ty: NtfsAttributeType::VolumeName,
+                expected: VOLUME_NAME_MAX_SIZE,
+                actual: value_length,
+            });
+        }
+
+        let name_position = value_attached.position();
+        let name_length = value_length as u16;
+
+        Ok(Self {
+            name_position,
+            name_length,
+        })
+    }
+
+    /// Returns the volume name length, in bytes.
+    ///
+    /// A volume name has a maximum length of 128 UTF-16 code points (256 bytes).
+    pub fn name_length(&self) -> usize {
+        self.name_length as usize
+    }
+
+    /// Reads the volume name into the given buffer, and returns an
+    /// [`NtfsString`] wrapping that buffer.
+    pub fn read_name<'a, T>(&self, fs: &mut T, buf: &'a mut [u8]) -> Result<NtfsString<'a>>
+    where
+        T: Read + Seek,
+    {
+        let name_length = self.name_length();
+        if buf.len() < name_length {
+            return Err(NtfsError::BufferTooSmall {
+                expected: name_length,
+                actual: buf.len(),
+            });
+        }
+
+        fs.seek(SeekFrom::Start(self.name_position))?;
+        fs.read_exact(&mut buf[..name_length])?;
+
+        Ok(NtfsString(&buf[..name_length]))
+    }
+}