Fix function ScrollViewCommand

The format string which builds the command only takes one or two
string arguments, so the function allocated too much memory and
passed too many arguments to snprintf.

This also fixes a compiler warning (clang).

Signed-off-by: Stefan Weil <sw@weilnetz.de>

Author: stweil

src/viewer/svutil.cpp

@@ -50,6 +50,7 @@ struct addrinfo {
 #include <iostream>
 #include <memory>
 #include <string>
+#include <vector>
 
 // Include automatically generated configuration file if running autoconf.
 #ifdef HAVE_CONFIG_H
@@ -301,19 +302,23 @@ static std::string ScrollViewCommand(std::string scrollview_path) {
   // this unnecessary.
   // Also the path has to be separated by ; on windows and : otherwise.
 #ifdef _WIN32
-  const char* cmd_template = "-Djava.library.path=%s -jar %s/ScrollView.jar";
+  const char cmd_template[] = "-Djava.library.path=%s -jar %s/ScrollView.jar";
 
 #else
-  const char* cmd_template =
+  const char cmd_template[] =
       "-c \"trap 'kill %%1' 0 1 2 ; java "
       "-Xms1024m -Xmx2048m -jar %s/ScrollView.jar"
       " & wait\"";
 #endif
-  size_t cmdlen = strlen(cmd_template) + 4 * strlen(scrollview_path.c_str()) + 1;
-  std::unique_ptr<char[]> cmd(new char[cmdlen]);
+  size_t cmdlen = sizeof(cmd_template) + 2 * scrollview_path.size() + 1;
+  std::vector<char> cmd(cmdlen);
   const char* sv_path = scrollview_path.c_str();
-  snprintf(cmd.get(), cmdlen, cmd_template, sv_path, sv_path, sv_path, sv_path);
-  std::string command(cmd.get());
+#ifdef _WIN32
+  snprintf(&cmd[0], cmdlen, cmd_template, sv_path, sv_path);
+#else
+  snprintf(&cmd[0], cmdlen, cmd_template, sv_path);
+#endif
+  std::string command(&cmd[0]);
   return command;
 }