src/path_parsing.rs in faster_path-0.2.2 vs src/path_parsing.rs in faster_path-0.2.3

@@ -1,55 +1,32 @@
+extern crate memchr;
+use self::memchr::memrchr;
 use std::path::MAIN_SEPARATOR;
+use std::str;
 
-static SEP: u8 = MAIN_SEPARATOR as u8;
+pub const SEP: u8 = MAIN_SEPARATOR as u8;
+lazy_static! {
+  pub static ref SEP_STR: &'static str = str::from_utf8(&[SEP]).unwrap();
+}
 
 pub fn extract_last_path_segment(path: &str) -> &str {
-  // Works with bytes directly because MAIN_SEPARATOR is always in the ASCII 7-bit range so we can
-  // avoid the overhead of full UTF-8 processing.
-  // See src/benches/path_parsing.rs for benchmarks of different approaches.
-  let ptr = path.as_ptr();
-  let mut i = path.len() as isize - 1;
-  while i >= 0 {
-    let c = unsafe { *ptr.offset(i) };
-    if c != SEP { break; };
-    i -= 1;
-  }
-  let end = (i + 1) as usize;
-  while i >= 0 {
-    let c = unsafe { *ptr.offset(i) };
-    if c == SEP {
-      return &path[(i + 1) as usize..end];
-    };
-    i -= 1;
-  }
-  &path[..end]
+  let end = (last_non_sep_i(path) + 1) as usize;
+  &path[memrchr(SEP, &path.as_bytes()[..end]).unwrap_or(0)..end]
 }
 
-
 // Returns the byte offset of the last byte preceding a MAIN_SEPARATOR.
 pub fn last_non_sep_i(path: &str) -> isize {
   last_non_sep_i_before(path, path.len() as isize - 1)
 }
 
 // Returns the byte offset of the last byte preceding a MAIN_SEPARATOR before the given end offset.
 pub fn last_non_sep_i_before(path: &str, end: isize) -> isize {
+  // Works with bytes directly because MAIN_SEPARATOR is always in the ASCII 7-bit range so we can
+  // avoid the overhead of full UTF-8 processing.
   let ptr = path.as_ptr();
   let mut i = end;
   while i >= 0 {
     if unsafe { *ptr.offset(i) } != SEP { break; };
     i -= 1;
   }
   i
-}
-
-// Returns the byte offset of the last MAIN_SEPARATOR before the given end offset.
-pub fn last_sep_i(path: &str, end: isize) -> isize {
-  let ptr = path.as_ptr();
-  let mut i = end - 1;
-  while i >= 0 {
-    if unsafe { *ptr.offset(i) } == SEP {
-      return i;
-    };
-    i -= 1;
-  }
-  -1
 }