separate partitions & partition tables

src/lib.rs

@@ -3,13 +3,17 @@
 extern crate alloc;
 
 use alloc::boxed::Box;
+use alloc::vec::Vec;
+
+// i chose this arbitrarily, but i don't think that many people will need to access over 67 million terabytes of data from a disk
+pub type Index = u64;
 
 /// # BlockDevice
 /// interface for accessing a block device, i.e. a device that can be randomly accessed in fixed-size blocks
 /// will be implemented in vapblock_* libraries
 pub trait BlockDevice {
-    /// moves the "cursor" to the given offset
-    fn seek(&mut self, offset: usize);
+    /// moves the "cursor" to the given offset, returns false on failure
+    fn seek(&mut self, offset: Index) -> bool;
     fn block_size(&self) -> usize;
     /// reads buf.len() bytes into buf, starting at the current offset
     /// returns the number of bytes read
@@ -22,11 +26,33 @@ pub trait BlockDevice {
     fn write_blocks(&mut self, buf: &[u8]) -> usize;
 }
 
+/// # BasicROPartition
+/// interface for a partition from a `BasicROPartitionTable`
+/// must implement `BlockDevice`
+pub trait BasicROPartition: BlockDevice {
+    /// returns a `&str` of this partition's type
+    /// implementation-specific
+    fn partition_type<'a>(&self) -> &'a str;
+    /// returns this partition's size in bytes
+    fn size(&self) -> Index;
+}
+
+/// # BasicROPartitionTable
+/// interface for basic interactions with a partition table over a block device
+pub trait BasicROPartitionTable<T: BasicROPartition, Sized> {
+    /// must be called before any other methods
+    fn init(&mut self, block_device: &mut dyn BlockDevice);
+    /// returns number of partitions
+    fn partition_count(&self) -> usize;
+    /// returns Vec of (partiton_name: &str, partition: BasicROPartition)
+    fn partitions<'a>(&self) -> Vec<(&'a str, &'a mut T)>;
+}
+
 /// # BasicROFile
 /// interface for basic interactions with a file on a BasicROFileSystem
 pub trait BasicROFile {
     /// moves the "cursor" to the given offset
-    fn seek(&mut self, offset: usize);
+    fn seek(&mut self, offset: Index);
     /// reads buf.len() bytes into buf, starting at the current offset
     /// returns the number of bytes read
     /// may return less than buf.len() if the end of the file is reached