piece-table: Don't allocate in piece_table_to_string

`piece_table_to_string` now receives a buffer and we also provide a
function that returns the length of the piece table.

TODO: the `piece_table_to_string` adds null termination, that makes the
buffer needed `piece_table_length(pt) + 1`. This we should document or
do more obvious.

2 files changed, 12 insertions, 7 deletions

diff --git a/src/piece-table.c b/src/piece-table.c
index a8ddd1e..b29f3be 100644
--- a/src/piece-table.c
+++ b/src/piece-table.c
@@ -415,15 +415,19 @@ piece_table_index (piece_table *pt, size_t pos)
                            pt->cached->start + pos - pt->cached_offset);
 }
 
-char *
-piece_table_to_string (piece_table *pt)
+void
+piece_table_to_string (piece_table *pt, char *buf)
 {
   size_t i;
-  char *ret = malloc (sizeof (*ret) * pt->length + 1);
   for (i = 0; i < pt->length; i++)
     {
-      ret[i] = piece_table_index(pt, i);
+      buf[i] = piece_table_index (pt, i);
     }
-  ret[i] = '\0';
-  return ret;
+  buf[i] = '\0';
+}
+
+size_t
+piece_table_length (piece_table *pt)
+{
+  return pt->length;
 }
diff --git a/src/piece-table.h b/src/piece-table.h
index c9d6601..e90d2fa 100644
--- a/src/piece-table.h
+++ b/src/piece-table.h
@@ -29,6 +29,7 @@ char piece_table_index (piece_table *pt, size_t pos);
 void piece_table_insert (piece_table *pt, size_t pos, char *in, size_t len);
 void piece_table_delete (piece_table *pt, size_t pos, size_t len);
 
-char *piece_table_to_string (piece_table *pt);
+void piece_table_to_string (piece_table *pt, char *buf);
+size_t piece_table_length (piece_table *pt);
 
 #endif