[gsoc-diff] reduce number of mallocs for gd-ptr

cha_alloc.diff

diff --git a/xdiff/xhistogram.c b/xdiff/xhistogram.c
index acb43d1..0bca160 100644
--- a/xdiff/xhistogram.c
+++ b/xdiff/xhistogram.c
@@ -14,6 +14,7 @@ struct histindex {
 		struct record *next;
 	} **records, /* an ocurrence */
 	  **line_map; /* map of line to record chain */
+	chastore_t rcha;
 	unsigned int *next_ptrs;
 	unsigned int table_bits,
 		     records_size,
@@ -92,8 +93,7 @@ static int scanA(struct histindex *index, int line1, int count1)
 			return -1;
 
 		/* first occurrence, create occurrence chain */
-		if (!(rec = (struct record *)
-			xdl_malloc(sizeof(struct record))))
+		if (!(rec = xdl_cha_alloc(&index->rcha)))
 			return -1;
 		rec->ptr = ptr;
 		rec->cnt = 1;
@@ -274,6 +274,10 @@ static int histogram_diff(xpparam_t const *xpp, xdfenv_t *env,
 		goto cleanup;
 	memset(index.next_ptrs, 0, sz);
 
+	index.rcha.head = NULL;
+	if (!xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1))
+		goto cleanup;
+
 	index.ptr_shift = line1;
 	index.max_chain_length = 64;
 
@@ -303,6 +307,7 @@ cleanup:
 	xdl_free(index.records);
 	xdl_free(index.line_map);
 	xdl_free(index.next_ptrs);
+	xdl_cha_free(&index.rcha);
 
 	return result;
 }