alloc_ref_from_str(): factor out a common pattern of alloc_ref from string

diff --git a/diffcore-delta.c b/diffcore-delta.c
index d9729e5ec27d2ff2bacf4ed930195f9293f8ca5a..e670f8512558c38d9a9d6e754cfc609b042b1195 100644 (file)
--- a/diffcore-delta.c
+++ b/diffcore-delta.c
@@ -46,22 +46,6 @@ struct spanhash_top {
        struct spanhash data[FLEX_ARRAY];
 };
 
-static struct spanhash *spanhash_find(struct spanhash_top *top,
-                                     unsigned int hashval)
-{
-       int sz = 1 << top->alloc_log2;
-       int bucket = hashval & (sz - 1);
-       while (1) {
-               struct spanhash *h = &(top->data[bucket++]);
-               if (!h->cnt)
-                       return NULL;
-               if (h->hashval == hashval)
-                       return h;
-               if (sz <= bucket)
-                       bucket = 0;
-       }
-}
-
 static struct spanhash_top *spanhash_rehash(struct spanhash_top *orig)
 {
        struct spanhash_top *new;
@@ -122,6 +106,20 @@ static struct spanhash_top *add_spanhash(struct spanhash_top *top,
        }
 }
 
+static int spanhash_cmp(const void *a_, const void *b_)
+{
+       const struct spanhash *a = a_;
+       const struct spanhash *b = b_;
+
+       /* A count of zero compares at the end.. */
+       if (!a->cnt)
+               return !b->cnt ? 0 : 1;
+       if (!b->cnt)
+               return -1;
+       return a->hashval < b->hashval ? -1 :
+               a->hashval > b->hashval ? 1 : 0;
+}
+
 static struct spanhash_top *hash_chars(struct diff_filespec *one)
 {
        int i, n;
@@ -158,6 +156,10 @@ static struct spanhash_top *hash_chars(struct diff_filespec *one)
                n = 0;
                accum1 = accum2 = 0;
        }
+       qsort(hash->data,
+               1ul << hash->alloc_log2,
+               sizeof(hash->data[0]),
+               spanhash_cmp);
        return hash;
 }
 
@@ -169,7 +171,7 @@ int diffcore_count_changes(struct diff_filespec *src,
                           unsigned long *src_copied,
                           unsigned long *literal_added)
 {
-       int i, ssz;
+       struct spanhash *s, *d;
        struct spanhash_top *src_count, *dst_count;
        unsigned long sc, la;
 
@@ -190,22 +192,26 @@ int diffcore_count_changes(struct diff_filespec *src,
        }
        sc = la = 0;
 
-       ssz = 1 << src_count->alloc_log2;
-       for (i = 0; i < ssz; i++) {
-               struct spanhash *s = &(src_count->data[i]);
-               struct spanhash *d;
+       s = src_count->data;
+       d = dst_count->data;
+       for (;;) {
                unsigned dst_cnt, src_cnt;
                if (!s->cnt)
-                       continue;
+                       break; /* we checked all in src */
+               while (d->cnt) {
+                       if (d->hashval >= s->hashval)
+                               break;
+                       d++;
+               }
                src_cnt = s->cnt;
-               d = spanhash_find(dst_count, s->hashval);
-               dst_cnt = d ? d->cnt : 0;
+               dst_cnt = d->hashval == s->hashval ? d->cnt : 0;
                if (src_cnt < dst_cnt) {
                        la += dst_cnt - src_cnt;
                        sc += src_cnt;
                }
                else
                        sc += dst_cnt;
+               s++;
        }
 
        if (!src_count_p)