fixed segfault when munging empty scripts

 * empty scripts are SciTECO scripts with an Hash-Bang line but no
   EOL characters.
   They are simply ignored now.
 * A test case cannot be added since 1) it's hard to create the test
   script with AT_DATA - we'd have to add it to the repo instead.
   2) If the bug is not occurring, SciTECO starts into interactive mode
   which cannot be inhibited unless the script is __not__ empty.
 * Skipping the Hash-Bang line is optimized now, saving one iteration
   of the macro just to find out it contains no CR (which is
   the most common case).

1 files changed, 10 insertions, 3 deletions

diff --git a/src/parser.cpp b/src/parser.cpp
index 1936837..97822e7 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -297,11 +297,17 @@ Execute::file(const gchar *filename, bool locals)
 
 	if (!g_file_get_contents(filename, &macro_str, NULL, &gerror))
 		throw GlibError(gerror);
+
 	/* only when executing files, ignore Hash-Bang line */
-	if (*macro_str == '#')
-		p = MAX(strchr(macro_str, '\r'), strchr(macro_str, '\n'))+1;
-	else
+	if (*macro_str == '#') {
+		p = strpbrk(macro_str, "\r\n");
+		if (G_UNLIKELY(!p))
+			/* empty script */
+			goto cleanup;
+		p++;
+	} else {
 		p = macro_str;
+	}
 
 	try {
 		macro(p, locals);
@@ -318,6 +324,7 @@ Execute::file(const gchar *filename, bool locals)
 		throw; /* forward */
 	}
 
+cleanup:
 	g_free(macro_str);
 }