Speed up approximate search for matching ChangeLog entries.

diff --git a/ChangeLog b/ChangeLog
index 0fdae2cf6d0c95418643ac9bba9bfcfba3aa2b1c..3919830a9dfc941abce52af98a52d6b7a3d9cbb7 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2009-07-02  Bruno Haible  <bruno@clisp.org>
+
+       Speed up approximate search for matching ChangeLog entries.
+       * lib/git-merge-changelog.c (entry_fstrcmp): Add a lower_bound
+       argument. Call fstrcmp_bounded instead of fstrcmp.
+       (compute_mapping, try_split_merged_entry, main): Update callers.
+
 2009-07-02  Bruno Haible  <bruno@clisp.org>
 
        * lib/git-merge-changelog.c (main): Add comment about git cherry-pick.

diff --git a/lib/git-merge-changelog.c b/lib/git-merge-changelog.c
index 7db745306c282c10b99d9c0ad10b7f19f0b49f00..986b8c832dc9c0c0898c3bad3ac14c0d1e8f6eca 100644 (file)
--- a/lib/git-merge-changelog.c
+++ b/lib/git-merge-changelog.c
@@ -211,9 +211,12 @@ entry_hashcode (const void *elt)
 
 /* Perform a fuzzy comparison of two ChangeLog entries.
    Return a similarity measure of the two entries, a value between 0 and 1.
-   0 stands for very distinct, 1 for identical.  */
+   0 stands for very distinct, 1 for identical.
+   If the result is < LOWER_BOUND, an arbitrary other value < LOWER_BOUND can
+   be returned.  */
 static double
-entry_fstrcmp (const struct entry *entry1, const struct entry *entry2)
+entry_fstrcmp (const struct entry *entry1, const struct entry *entry2,
+              double lower_bound)
 {
   /* fstrcmp works only on NUL terminated strings.  */
   char *memory;
@@ -233,7 +236,8 @@ entry_fstrcmp (const struct entry *entry1, const struct entry *entry2)
     p += entry2->length;
     *p++ = '\0';
   }
-  similarity = fstrcmp (memory, memory + entry1->length + 1);
+  similarity =
+    fstrcmp_bounded (memory, memory + entry1->length + 1, lower_bound);
   freea (memory);
   return similarity;
 }
@@ -410,7 +414,8 @@ compute_mapping (struct changelog_file *file1, struct changelog_file *file2,
        for (j = n2 - 1; j >= 0; j--)
          if (index_mapping_reverse[j] < 0)
            {
-             double similarity = entry_fstrcmp (entry_i, file2->entries[j]);
+             double similarity =
+               entry_fstrcmp (entry_i, file2->entries[j], best_j_similarity);
              if (similarity > best_j_similarity)
                {
                  best_j = j;
@@ -429,7 +434,8 @@ compute_mapping (struct changelog_file *file1, struct changelog_file *file2,
              if (index_mapping[ii] < 0)
                {
                  double similarity =
-                   entry_fstrcmp (file1->entries[ii], entry_j);
+                   entry_fstrcmp (file1->entries[ii], entry_j,
+                                  best_i_similarity);
                  if (similarity > best_i_similarity)
                    {
                      best_i = i;
@@ -729,7 +735,8 @@ try_split_merged_entry (const struct entry *old_entry,
 
       new_body.string = new_entry->string + split_offset;
       new_body.length = new_entry->length - split_offset;
-      similarity = entry_fstrcmp (&old_body, &new_body);
+      similarity =
+       entry_fstrcmp (&old_body, &new_body, best_similarity);
       if (similarity > best_similarity)
        {
          best_split_offset = split_offset;
@@ -1219,7 +1226,8 @@ There is NO WARRANTY, to the extent permitted by law.\n\
                            size_t i;
                            for (i = edit->i1 + 1; i <= edit->i2; i++)
                              if (entry_fstrcmp (ancestor_file.entries[i],
-                                                modified_file.entries[i + edit->j2 - edit->i2])
+                                                modified_file.entries[i + edit->j2 - edit->i2],
+                                                FSTRCMP_THRESHOLD)
                                  < FSTRCMP_THRESHOLD)
                                {
                                  simple_merged = false;
@@ -1300,7 +1308,8 @@ There is NO WARRANTY, to the extent permitted by law.\n\
                        simple = true;
                        for (i = edit->i1; i <= edit->i2; i++)
                          if (entry_fstrcmp (ancestor_file.entries[i],
-                                            modified_file.entries[i + edit->j2 - edit->i2])
+                                            modified_file.entries[i + edit->j2 - edit->i2],
+                                            FSTRCMP_THRESHOLD)
                              < FSTRCMP_THRESHOLD)
                            {
                              simple = false;