diff --git a/lib/chalib.c b/lib/chalib.c
index 5d79e13..cddf51b 100644
--- a/lib/chalib.c
+++ b/lib/chalib.c
@@ -306,9 +306,14 @@ chasen_sparse_main(char *input, FILE *output)
      */
     while (*input) {
 	int c = 0, len, cursor;
-	if ((crlf = strpbrk(input, "\r\n")) == NULL)
+	if ((crlf = strpbrk(input, "\r\n")) == NULL) {
 	    len = strlen(input);
-	else {
+	    if (len >= CHA_INPUT_SIZE) {
+		len = CHA_INPUT_SIZE - 1;
+		crlf = input + CHA_INPUT_SIZE - 2;
+		c = 0;
+	    }
+	} else {
 	    len = crlf - input;
 	    c = *crlf;
 	    *crlf = '\0';