From cd7e77e1b474cbffaea2b2abe234e8eea7929c32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Harabie=C5=84?= <rafalh1992@o2.pl>
Date: Mon, 25 Jun 2018 00:22:34 +0200
Subject: [PATCH] Rename directory entry flags and add some internal docs

---
 src/dir.rs       | 10 +++++-----
 src/dir_entry.rs | 43 +++++++++++++++++++++++++------------------
 2 files changed, 30 insertions(+), 23 deletions(-)

diff --git a/src/dir.rs b/src/dir.rs
index f167ad8..e20117e 100644
--- a/src/dir.rs
+++ b/src/dir.rs
@@ -280,7 +280,7 @@ impl <'a, T: ReadWriteSeek + 'a> Dir<'a, T> {
         for _ in 0..num {
             let mut data = DirEntryData::deserialize(&mut stream)?;
             trace!("removing dir entry {:?}", data);
-            data.set_free();
+            data.set_deleted();
             stream.seek(SeekFrom::Current(-(DIR_ENTRY_SIZE as i64)))?;
             data.serialize(&mut stream)?;
         }
@@ -335,7 +335,7 @@ impl <'a, T: ReadWriteSeek + 'a> Dir<'a, T> {
         for _ in 0..num {
             let mut data = DirEntryData::deserialize(&mut stream)?;
             trace!("removing LFN entry {:?}", data);
-            data.set_free();
+            data.set_deleted();
             stream.seek(SeekFrom::Current(-(DIR_ENTRY_SIZE as i64)))?;
             data.serialize(&mut stream)?;
         }
@@ -359,7 +359,7 @@ impl <'a, T: ReadWriteSeek + 'a> Dir<'a, T> {
                 }
                 stream.seek(io::SeekFrom::Start(first_free as u64 * DIR_ENTRY_SIZE))?;
                 return Ok(stream);
-            } else if raw_entry.is_free() {
+            } else if raw_entry.is_deleted() {
                 // free entry - calculate number of free entries in a row
                 if num_free == 0 {
                     first_free = i;
@@ -470,7 +470,7 @@ impl <'a, T: ReadWriteSeek> DirIter<'a, T> {
                         return Ok(None);
                     }
                     // Check if this is deleted or volume ID entry
-                    if data.is_free() || data.is_volume() {
+                    if data.is_deleted() || data.is_volume() {
                         #[cfg(feature = "alloc")]
                         lfn_buf.clear();
                         begin_offset = offset;
@@ -495,7 +495,7 @@ impl <'a, T: ReadWriteSeek> DirIter<'a, T> {
                 },
                 DirEntryData::Lfn(data) => {
                     // Check if this is deleted entry
-                    if data.is_free() {
+                    if data.is_deleted() {
                         #[cfg(feature = "alloc")]
                         lfn_buf.clear();
                         begin_offset = offset;
diff --git a/src/dir_entry.rs b/src/dir_entry.rs
index 0f67ca8..b80b9b0 100644
--- a/src/dir_entry.rs
+++ b/src/dir_entry.rs
@@ -34,11 +34,18 @@ bitflags! {
     }
 }
 
-pub(crate) const LFN_PART_LEN: usize = 13;
+// Size of single directory entry in bytes
 pub(crate) const DIR_ENTRY_SIZE: u64 = 32;
-pub(crate) const DIR_ENTRY_FREE_FLAG: u8 = 0xE5;
+
+// Directory entry flags available in first byte of the short name
+pub(crate) const DIR_ENTRY_DELETED_FLAG: u8 = 0xE5;
+pub(crate) const DIR_ENTRY_REALLY_E5_FLAG: u8 = 0x05;
+
+// Length in characters of a LFN fragment packed in one directory entry
+pub(crate) const LFN_PART_LEN: usize = 13;
+
+// Bit used in order field to mark last LFN entry
 pub(crate) const LFN_ENTRY_LAST_FLAG: u8 = 0x40;
-pub(crate) const LFN_ENTRY_REALLY_E5_FLAG: u8 = 0x05;
 
 /// Decoded file short name
 #[derive(Clone, Debug, Default)]
@@ -66,7 +73,7 @@ impl ShortName {
             name_len
         };
         // FAT encodes character 0xE5 as 0x05 because 0xE5 marks deleted files
-        if name[0] == LFN_ENTRY_REALLY_E5_FLAG {
+        if name[0] == DIR_ENTRY_REALLY_E5_FLAG {
             name[0] = 0xE5;
         }
         // Short names in FAT filesystem are encoded in OEM code-page
@@ -272,12 +279,12 @@ impl DirFileEntryData {
         Ok(())
     }
 
-    pub(crate) fn is_free(&self) -> bool {
-        self.name[0] == DIR_ENTRY_FREE_FLAG
+    pub(crate) fn is_deleted(&self) -> bool {
+        self.name[0] == DIR_ENTRY_DELETED_FLAG
     }
 
-    pub(crate) fn set_free(&mut self) {
-        self.name[0] = DIR_ENTRY_FREE_FLAG;
+    pub(crate) fn set_deleted(&mut self) {
+        self.name[0] = DIR_ENTRY_DELETED_FLAG;
     }
 
     pub(crate) fn is_end(&self) -> bool {
@@ -352,12 +359,12 @@ impl DirLfnEntryData {
         self.checksum
     }
 
-    pub(crate) fn is_free(&self) -> bool {
-        self.order == DIR_ENTRY_FREE_FLAG
+    pub(crate) fn is_deleted(&self) -> bool {
+        self.order == DIR_ENTRY_DELETED_FLAG
     }
 
-    pub(crate) fn set_free(&mut self) {
-        self.order = DIR_ENTRY_FREE_FLAG;
+    pub(crate) fn set_deleted(&mut self) {
+        self.order = DIR_ENTRY_DELETED_FLAG;
     }
 
     pub(crate) fn is_end(&self) -> bool {
@@ -428,17 +435,17 @@ impl DirEntryData {
         }
     }
 
-    pub(crate) fn is_free(&self) -> bool {
+    pub(crate) fn is_deleted(&self) -> bool {
         match self {
-            &DirEntryData::File(ref file) => file.is_free(),
-            &DirEntryData::Lfn(ref lfn) => lfn.is_free(),
+            &DirEntryData::File(ref file) => file.is_deleted(),
+            &DirEntryData::Lfn(ref lfn) => lfn.is_deleted(),
         }
     }
 
-    pub(crate) fn set_free(&mut self) {
+    pub(crate) fn set_deleted(&mut self) {
         match self {
-            &mut DirEntryData::File(ref mut file) => file.set_free(),
-            &mut DirEntryData::Lfn(ref mut lfn) => lfn.set_free(),
+            &mut DirEntryData::File(ref mut file) => file.set_deleted(),
+            &mut DirEntryData::Lfn(ref mut lfn) => lfn.set_deleted(),
         }
     }