Add MAX_INDENT for xml.

Otherwise we can get quadratic increase in size with deeply
nested structures.

See #355.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/xml.c b/src/xml.c
index 731bc01..f1dcfd2 100644
--- a/src/xml.c
+++ b/src/xml.c
@@ -10,6 +10,7 @@
 #include "houdini.h"
 
 #define BUFFER_SIZE 100
+#define MAX_INDENT 40
 
 // Functions to convert cmark_nodes to XML strings.
 
@@ -30,7 +31,7 @@ struct render_state {
 
 static CMARK_INLINE void indent(struct render_state *state) {
   int i;
-  for (i = 0; i < state->indent; i++) {
+  for (i = 0; i < state->indent && i < MAX_INDENT; i++) {
     cmark_strbuf_putc(state->xml, ' ');
   }
 }