Add helper_functions.cpp/hpp & unit tests

- add function which constructs a new std::string from a potentially not null
  terminated char *
- add unit tests

src/CMakeLists.txt

@@ -17,6 +17,7 @@ set( LIBEXIV2_SRC
     exif.cpp
     futils.cpp
     gifimage.cpp
+    helper_functions.cpp
     http.cpp
     image.cpp
     ini.cpp

src/helper_functions.cpp

@@ -0,0 +1,41 @@
+// ********************************************************* -*- C++ -*-
+/*
+ * Copyright (C) 2004-2018 Exiv2 authors
+ *
+ * This program is part of the Exiv2 distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
+ */
+/*!
+  @file    helper_functions.cpp
+  @brief   A collection of helper functions
+  @author  Dan Čermák (D4N)
+           <a href="mailto:dan.cermak@cgc-instruments.com">dan.cermak@cgc-instruments.com</a>
+  @date    25-May-18, D4N: created
+ */
+
+#include "helper_functions.hpp"
+
+#include <algorithm>
+
+
+std::string string_from_unterminated(const char* data, size_t data_length)
+{
+    const char* termination = std::find(data, data + data_length, 0);
+    // if find returned the end iterator => no \0 found
+    const size_t string_length = termination == data + data_length ? data_length : termination - data;
+
+    return std::string(data, string_length);
+}

src/helper_functions.hpp

@@ -0,0 +1,43 @@
+// ********************************************************* -*- C++ -*-
+/*
+ * Copyright (C) 2004-2018 Exiv2 authors
+ *
+ * This program is part of the Exiv2 distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, 5th Floor, Boston, MA 02110-1301 USA.
+ */
+/*!
+  @file    helper_functions.hpp
+  @brief   A collection of helper functions
+  @author  Dan Čermák (D4N)
+           <a href="mailto:dan.cermak@cgc-instruments.com">dan.cermak@cgc-instruments.com</a>
+  @date    25-May-18, D4N: created
+ */
+#ifndef HELPER_FUNCTIONS_HPP
+#define HELPER_FUNCTIONS_HPP
+
+#include <string>
+
+/*!
+  @brief Convert a (potentially not null terminated) array into a
+  std::string.
+
+  Convert a C style string that may or may not be null terminated safely
+  into a std::string. The string's termination is either set at the first \0
+  or after data_length characters.
+ */
+std::string string_from_unterminated(const char* data, size_t data_length);
+
+#endif  // HELPER_FUNCTIONS_HPP

unitTests/CMakeLists.txt

@@ -8,6 +8,7 @@ add_executable(unit_tests mainTestRunner.cpp
     test_XmpKey.cpp
     test_DateValue.cpp
     test_cr2header_int.cpp
+    test_helper_functions.cpp
 )
 
 #TODO Use GTest::GTest once we upgrade the minimum CMake version required

unitTests/test_helper_functions.cpp

@@ -0,0 +1,21 @@
+#include "helper_functions.hpp"
+
+#include "gtestwrapper.h"
+
+TEST(string_from_unterminated, terminatedArray)
+{
+    const char data[5] = {'a', 'b', 'c', 0, 'd'};
+    const std::string res = string_from_unterminated(data, 5);
+
+    ASSERT_EQ(res.size(), 3);
+    ASSERT_STREQ(res.c_str(), "abc");
+}
+
+TEST(string_from_unterminated, unterminatedArray)
+{
+    const char data[4] = {'a', 'b', 'c', 'd'};
+    const std::string res = string_from_unterminated(data, 4);
+
+    ASSERT_EQ(res.size(), 4);
+    ASSERT_STREQ(res.c_str(), "abcd");
+}