blame: use a helper function in blame_chunk()

The same code for splitting a blame_entry at a particular line was used
twice in blame_chunk(), and I'll use the helper again in an upcoming
patch.

Signed-off-by: Barret Rhoden <brho@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

blame.c

@@ -838,6 +838,27 @@ static struct blame_entry *reverse_blame(struct blame_entry *head,
 	return tail;
 }
 
+/*
+ * Splits a blame entry into two entries at 'len' lines.  The original 'e'
+ * consists of len lines, i.e. [e->lno, e->lno + len), and the second part,
+ * which is returned, consists of the remainder: [e->lno + len, e->lno +
+ * e->num_lines).  The caller needs to sort out the reference counting for the
+ * new entry's suspect.
+ */
+static struct blame_entry *split_blame_at(struct blame_entry *e, int len,
+					  struct blame_origin *new_suspect)
+{
+	struct blame_entry *n = xcalloc(1, sizeof(struct blame_entry));
+
+	n->suspect = new_suspect;
+	n->lno = e->lno + len;
+	n->s_lno = e->s_lno + len;
+	n->num_lines = e->num_lines - len;
+	e->num_lines = len;
+	e->score = 0;
+	return n;
+}
+
 /*
  * Process one hunk from the patch between the current suspect for
  * blame_entry e and its parent.  This first blames any unfinished
@@ -864,14 +885,9 @@ static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
 		 */
 		if (e->s_lno + e->num_lines > tlno) {
 			/* Move second half to a new record */
-			int len = tlno - e->s_lno;
-			struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
-			n->suspect = e->suspect;
-			n->lno = e->lno + len;
-			n->s_lno = e->s_lno + len;
-			n->num_lines = e->num_lines - len;
-			e->num_lines = len;
-			e->score = 0;
+			struct blame_entry *n;
+
+			n = split_blame_at(e, tlno - e->s_lno, e->suspect);
 			/* Push new record to diffp */
 			n->next = diffp;
 			diffp = n;
@@ -918,14 +934,10 @@ static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
 			 * Move second half to a new record to be
 			 * processed by later chunks
 			 */
-			int len = same - e->s_lno;
-			struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
-			n->suspect = blame_origin_incref(e->suspect);
-			n->lno = e->lno + len;
-			n->s_lno = e->s_lno + len;
-			n->num_lines = e->num_lines - len;
-			e->num_lines = len;
-			e->score = 0;
+			struct blame_entry *n;
+
+			n = split_blame_at(e, same - e->s_lno,
+					   blame_origin_incref(e->suspect));
 			/* Push new record to samep */
 			n->next = samep;
 			samep = n;