Check length before reading.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/blocks.c b/src/blocks.c
index 4acd899..777356a 100644
--- a/src/blocks.c
+++ b/src/blocks.c
@@ -561,10 +561,10 @@ S_process_line(cmark_parser *parser, const unsigned char *buffer, size_t bytes)
 
 	// Add a newline to the end if not present:
 	// TODO this breaks abstraction:
-	if (parser->curline->ptr[parser->curline->size - 1] == '\n') {
+	if (parser->curline->size && parser->curline->ptr[parser->curline->size - 1] == '\n') {
 		cmark_strbuf_truncate(parser->curline, parser->curline->size - 1);
 	}
-	if (parser->curline->ptr[parser->curline->size - 1] == '\r') {
+	if (parser->curline->size && parser->curline->ptr[parser->curline->size - 1] == '\r') {
 		cmark_strbuf_truncate(parser->curline, parser->curline->size - 1);
 	}
 	cmark_strbuf_putc(parser->curline, '\n');