---

yaml
---
r: 154575
b: refs/heads/try2
c: 9a43492
h: refs/heads/master
i:
  154573: bd8bd4f
  154571: 2d20b71
  154567: 6952a2f
  154559: c0c9791
v: v3

Author: nham

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 9419e9265950a16f873dbed49c715fd7ea4e08e7
+refs/heads/try2: 9a43492f59bfc38ed819e361c3cf99aa7b972e15
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/libcore/str.rs

@@ -439,9 +439,13 @@ impl TwoWaySearcher {
         let byteset = needle.iter()
                             .fold(0, |a, &b| (1 << ((b & 0x3f) as uint)) | a);
 
-        // Check if the needle is periodic. If so, during searching when we
-        // find a mismatch, we must only advance the position by the length
-        // of the period, not the length of the entire needle
+
+        // The logic here (calculating critPos and period, the final if statement to see which
+        // period to use for the TwoWaySearcher) is essentially an implementation of the
+        // "small-period" function from the paper (p. 670)
+        //
+        // In the paper they check whether `needle.slice_to(critPos)` is a suffix of
+        // `needle.slice(critPos, critPos + period)`, which is precisely what this does
         if needle.slice_to(critPos) == needle.slice(period, period + critPos) {
             TwoWaySearcher {
                 critPos: critPos,
@@ -513,6 +517,9 @@ impl TwoWaySearcher {
         }
     }
 
+    // returns (i, p) where i is the "critical position", the starting index of
+    // of maximal suffix, and p is the period of the suffix
+    // see p. 668 of the paper
     #[inline]
     fn maximal_suffix(arr: &[u8], reversed: bool) -> (uint, uint) {
         let mut left = -1; // Corresponds to i in the paper