Refactored platform-specific code

Moved functions from .h to .cpp files

10 files changed, 410 insertions, 263 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index e6b3acd..cc181f2 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -55,11 +55,21 @@ if (${OPENAL_SOUND})
     )
 endif()
 
+# Platform-dependent implementation of system.h
+if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+    set(SYSTEM_CPP_MODULE "system_windows.cpp")
+elseif(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+    set(SYSTEM_CPP_MODULE "system_linux.cpp")
+else()
+    set(SYSTEM_CPP_MODULE "system_other.cpp")
+endif()
+
 # Source files
 set(SOURCES
 app/app.cpp
 app/main.cpp
 app/system.cpp
+app/${SYSTEM_CPP_MODULE}
 common/event.cpp
 common/image.cpp
 common/iman.cpp
diff --git a/src/app/system_linux.cpp b/src/app/system_linux.cpp
new file mode 100644
index 0000000..c6b6a6e
--- /dev/null
+++ b/src/app/system_linux.cpp
@@ -0,0 +1,79 @@
+// * This file is part of the COLOBOT source code
+// * Copyright (C) 2001-2008, Daniel ROUX & EPSITEC SA, www.epsitec.ch
+// * Copyright (C) 2012, Polish Portal of Colobot (PPC)
+// *
+// * 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 3 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, see  http://www.gnu.org/licenses/.
+
+#include "app/system_linux.h"
+
+#include <stdlib.h>
+
+
+SystemDialogResult SystemDialog_Linux(SystemDialogType type, const std::string& title, const std::string& message)
+{
+    std::string options = "";
+    switch (type)
+    {
+        case SDT_INFO:
+        default:
+            options = "--info";
+            break;
+        case SDT_WARNING:
+            options = "--warning";
+            break;
+        case SDT_ERROR:
+            options = "--error";
+            break;
+        case SDT_YES_NO:
+            options = "--question --ok-label=\"Yes\" --cancel-label=\"No\"";
+            break;
+        case SDT_OK_CANCEL:
+            options = "--question --ok-label=\"OK\" --cancel-label=\"Cancel\"";
+            break;
+    }
+
+    std::string command = "zenity " + options + " --text=\"" + message + "\" --title=\"" + title + "\"";
+    int code = system(command.c_str());
+
+    SystemDialogResult result = SDR_OK;
+    switch (type)
+    {
+        case SDT_YES_NO:
+            result = code ? SDR_NO : SDR_YES;
+            break;
+        case SDT_OK_CANCEL:
+            result = code ? SDR_CANCEL : SDR_OK;
+            break;
+        default:
+            break;
+    }
+
+    return result;
+}
+
+void GetCurrentTimeStamp_Linux(SystemTimeStamp *stamp)
+{
+    clock_gettime(CLOCK_MONOTONIC, &stamp->clockTime);
+}
+
+long long GetTimeStampExactResolution_Linux()
+{
+    return 1ll;
+}
+
+long long TimeStampExactDiff_Linux(SystemTimeStamp *before, SystemTimeStamp *after)
+{
+    return (after->clockTime.tv_nsec - before->clockTime.tv_nsec) +
+           (after->clockTime.tv_sec  - before->clockTime.tv_sec) * 1000000000ll;
+}
diff --git a/src/app/system_linux.h b/src/app/system_linux.h
index 69893de..bc07c31 100644
--- a/src/app/system_linux.h
+++ b/src/app/system_linux.h
@@ -20,20 +20,11 @@
  * \brief Linux-specific implementation of system functions
  */
 
-/* NOTE: code is contained in this header;
- * there is no separate .cpp module for simplicity */
+#include "app/system.h"
 
 #include <sys/time.h>
-#include <time.h>
-#include <stdlib.h>
 
 
-SystemDialogResult SystemDialog_Linux(SystemDialogType type, const std::string& title, const std::string& message);
-
-void GetCurrentTimeStamp_Linux(SystemTimeStamp *stamp);
-long long GetTimeStampExactResolution_Linux();
-long long TimeStampExactDiff_Linux(SystemTimeStamp *before, SystemTimeStamp *after);
-
 struct SystemTimeStamp
 {
     timespec clockTime;
@@ -45,60 +36,8 @@ struct SystemTimeStamp
 };
 
 
-SystemDialogResult SystemDialog_Linux(SystemDialogType type, const std::string& title, const std::string& message)
-{
-    std::string options = "";
-    switch (type)
-    {
-        case SDT_INFO:
-        default:
-            options = "--info";
-            break;
-        case SDT_WARNING:
-            options = "--warning";
-            break;
-        case SDT_ERROR:
-            options = "--error";
-            break;
-        case SDT_YES_NO:
-            options = "--question --ok-label=\"Yes\" --cancel-label=\"No\"";
-            break;
-        case SDT_OK_CANCEL:
-            options = "--question --ok-label=\"OK\" --cancel-label=\"Cancel\"";
-            break;
-    }
-
-    std::string command = "zenity " + options + " --text=\"" + message + "\" --title=\"" + title + "\"";
-    int code = system(command.c_str());
-
-    SystemDialogResult result = SDR_OK;
-    switch (type)
-    {
-        case SDT_YES_NO:
-            result = code ? SDR_NO : SDR_YES;
-            break;
-        case SDT_OK_CANCEL:
-            result = code ? SDR_CANCEL : SDR_OK;
-            break;
-        default:
-            break;
-    }
-
-    return result;
-}
-
-void GetCurrentTimeStamp_Linux(SystemTimeStamp *stamp)
-{
-    clock_gettime(CLOCK_MONOTONIC, &stamp->clockTime);
-}
-
-long long GetTimeStampExactResolution_Linux()
-{
-    return 1ll;
-}
+SystemDialogResult SystemDialog_Linux(SystemDialogType type, const std::string& title, const std::string& message);
 
-long long TimeStampExactDiff_Linux(SystemTimeStamp *before, SystemTimeStamp *after)
-{
-    return (after->clockTime.tv_nsec - before->clockTime.tv_nsec) +
-           (after->clockTime.tv_sec  - before->clockTime.tv_sec) * 1000000000ll;
-}
+void GetCurrentTimeStamp_Linux(SystemTimeStamp *stamp);
+long long GetTimeStampExactResolution_Linux();
+long long TimeStampExactDiff_Linux(SystemTimeStamp *before, SystemTimeStamp *after);
diff --git a/src/app/system_other.cpp b/src/app/system_other.cpp
new file mode 100644
index 0000000..006bf6d
--- /dev/null
+++ b/src/app/system_other.cpp
@@ -0,0 +1,122 @@
+// * This file is part of the COLOBOT source code
+// * Copyright (C) 2001-2008, Daniel ROUX & EPSITEC SA, www.epsitec.ch
+// * Copyright (C) 2012, Polish Portal of Colobot (PPC)
+// *
+// * 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 3 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, see  http://www.gnu.org/licenses/.
+
+#include "app/system_other.h"
+
+
+SystemDialogResult SystemDialog_Other(SystemDialogType type, const std::string& title, const std::string& message)
+{
+    switch (type)
+    {
+        case SDT_INFO:
+            std::cout << "INFO: ";
+            break;
+        case SDT_WARNING:
+            std::cout << "WARNING:";
+            break;
+        case SDT_ERROR:
+            std::cout << "ERROR: ";
+            break;
+        case SDT_YES_NO:
+        case SDT_OK_CANCEL:
+            std::cout << "QUESTION: ";
+            break;
+    }
+
+    std::cout << message << std::endl;
+
+    std::string line;
+
+    SystemDialogResult result = SDR_OK;
+
+    bool done = false;
+    while (!done)
+    {
+        switch (type)
+        {
+            case SDT_INFO:
+            case SDT_WARNING:
+            case SDT_ERROR:
+                std::cout << "Press ENTER to continue";
+                break;
+
+            case SDT_YES_NO:
+                std::cout << "Type 'Y' for Yes or 'N' for No";
+                break;
+
+            case SDT_OK_CANCEL:
+                std::cout << "Type 'O' for OK or 'C' for Cancel";
+                break;
+        }
+
+        std::getline(std::cin, line);
+
+        switch (type)
+        {
+            case SDT_INFO:
+            case SDT_WARNING:
+            case SDT_ERROR:
+                done = true;
+                break;
+
+            case SDT_YES_NO:
+                if (line == "Y" || line == "y")
+                {
+                    result = SDR_YES;
+                    done = true;
+                }
+                else if (line == "N" || line == "n")
+                {
+                    result = SDR_NO;
+                    done = true;
+                }
+                break;
+
+            case SDT_OK_CANCEL:
+                if (line == "O" || line == "o")
+                {
+                    done = true;
+                    result = SDR_OK;
+                }
+                else if (line == "C" || line == "c")
+                {
+                    done = true;
+                    result = SDR_CANCEL;
+                }
+                break;
+        }
+    }
+
+    return result;
+}
+
+
+
+void GetCurrentTimeStamp_Other(SystemTimeStamp *stamp)
+{
+    stamp->sdlTicks = SDL_GetTicks();
+}
+
+long long GetTimeStampExactResolution_Other()
+{
+    return 1000000ll;
+}
+
+long long TimeStampExactDiff_Other(SystemTimeStamp *before, SystemTimeStamp *after)
+{
+    return (after->sdlTicks - before->sdlTicks) * 1000000ll;
+}
diff --git a/src/app/system_other.h b/src/app/system_other.h
index eff0c8a..6fb4b86 100644
--- a/src/app/system_other.h
+++ b/src/app/system_other.h
@@ -20,20 +20,13 @@
  * \brief Fallback code for other systems
  */
 
-/* NOTE: code is contained in this header;
- * there is no separate .cpp module for simplicity */
+#include "app/system.h"
 
 #include <SDL/SDL.h>
 
 #include <iostream>
 
 
-SystemDialogResult SystemDialog_Other(SystemDialogType type, const std::string& title, const std::string& message);
-
-void GetCurrentTimeStamp_Other(SystemTimeStamp *stamp);
-long long GetTimeStampExactResolution_Other();
-long long TimeStampExactDiff_Other(SystemTimeStamp *before, SystemTimeStamp *after);
-
 struct SystemTimeStamp
 {
     Uint32 sdlTicks;
@@ -45,105 +38,8 @@ struct SystemTimeStamp
 };
 
 
-SystemDialogResult SystemDialog_Other(SystemDialogType type, const std::string& title, const std::string& message)
-{
-    switch (type)
-    {
-        case SDT_INFO:
-            std::cout << "INFO: ";
-            break;
-        case SDT_WARNING:
-            std::cout << "WARNING:";
-            break;
-        case SDT_ERROR:
-            std::cout << "ERROR: ";
-            break;
-        case SDT_YES_NO:
-        case SDT_OK_CANCEL:
-            std::cout << "QUESTION: ";
-            break;
-    }
-
-    std::cout << message << std::endl;
-
-    std::string line;
-
-    SystemDialogResult result = SDR_OK;
-
-    bool done = false;
-    while (!done)
-    {
-        switch (type)
-        {
-            case SDT_INFO:
-            case SDT_WARNING:
-            case SDT_ERROR:
-                std::cout << "Press ENTER to continue";
-                break;
-
-            case SDT_YES_NO:
-                std::cout << "Type 'Y' for Yes or 'N' for No";
-                break;
-
-            case SDT_OK_CANCEL:
-                std::cout << "Type 'O' for OK or 'C' for Cancel";
-                break;
-        }
-
-        std::getline(std::cin, line);
-
-        switch (type)
-        {
-            case SDT_INFO:
-            case SDT_WARNING:
-            case SDT_ERROR:
-                done = true;
-                break;
-
-            case SDT_YES_NO:
-                if (line == "Y" || line == "y")
-                {
-                    result = SDR_YES;
-                    done = true;
-                }
-                else if (line == "N" || line == "n")
-                {
-                    result = SDR_NO;
-                    done = true;
-                }
-                break;
-
-            case SDT_OK_CANCEL:
-                if (line == "O" || line == "o")
-                {
-                    done = true;
-                    result = SDR_OK;
-                }
-                else if (line == "C" || line == "c")
-                {
-                    done = true;
-                    result = SDR_CANCEL;
-                }
-                break;
-        }
-    }
-
-    return result;
-}
-
-
-
-void GetCurrentTimeStamp_Other(SystemTimeStamp *stamp)
-{
-    stamp->sdlTicks = SDL_GetTicks();
-}
-
-long long GetTimeStampExactResolution_Other()
-{
-    return 1000000ll;
-}
+SystemDialogResult SystemDialog_Other(SystemDialogType type, const std::string& title, const std::string& message);
 
-long long TimeStampExactDiff_Other(SystemTimeStamp *before, SystemTimeStamp *after)
-{
-    return (after->sdlTicks - before->sdlTicks) * 1000000ll;
-}
+void GetCurrentTimeStamp_Other(SystemTimeStamp *stamp);
+long long GetTimeStampExactResolution_Other();
+long long TimeStampExactDiff_Other(SystemTimeStamp *before, SystemTimeStamp *after);
diff --git a/src/app/system_windows.cpp b/src/app/system_windows.cpp
new file mode 100644
index 0000000..34fa57e
--- /dev/null
+++ b/src/app/system_windows.cpp
@@ -0,0 +1,98 @@
+// * This file is part of the COLOBOT source code
+// * Copyright (C) 2001-2008, Daniel ROUX & EPSITEC SA, www.epsitec.ch
+// * Copyright (C) 2012, Polish Portal of Colobot (PPC)
+// *
+// * 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 3 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, see  http://www.gnu.org/licenses/.
+
+#include "app/system_windows.h"
+
+
+// Convert a wide Unicode string to an UTF8 string
+std::string UTF8_Encode_Windows(const std::wstring &wstr)
+{
+    int size_needed = WideCharToMultiByte(CP_UTF8, 0, &wstr[0], static_cast<int>(wstr.size()), NULL, 0, NULL, NULL);
+    std::string strTo(size_needed, 0);
+    WideCharToMultiByte(CP_UTF8, 0, &wstr[0], static_cast<int>(wstr.size()), &strTo[0], size_needed, NULL, NULL);
+    return strTo;
+}
+
+// Convert an UTF8 string to a wide Unicode String
+std::wstring UTF8_Decode_Windows(const std::string &str)
+{
+    int size_needed = MultiByteToWideChar(CP_UTF8, 0, &str[0], static_cast<int>(str.size()), NULL, 0);
+    std::wstring wstrTo(size_needed, 0);
+    MultiByteToWideChar(CP_UTF8, 0, &str[0], static_cast<int>(str.size()), &wstrTo[0], size_needed);
+    return wstrTo;
+}
+
+SystemDialogResult SystemDialog_Windows(SystemDialogType type, const std::string& title, const std::string& message)
+{
+    unsigned int windowsType = 0;
+    std::wstring windowsMessage = UTF8_Decode_Windows(message);
+    std::wstring windowsTitle = UTF8_Decode_Windows(title);
+
+    switch (type)
+    {
+        case SDT_INFO:
+        default:
+            windowsType = MB_ICONINFORMATION|MB_OK;
+            break;
+        case SDT_WARNING:
+            windowsType = MB_ICONWARNING|MB_OK;
+            break;
+        case SDT_ERROR:
+            windowsType = MB_ICONERROR|MB_OK;
+            break;
+        case SDT_YES_NO:
+            windowsType = MB_ICONQUESTION|MB_YESNO;
+            break;
+        case SDT_OK_CANCEL:
+            windowsType = MB_ICONWARNING|MB_OKCANCEL;
+            break;
+    }
+
+    switch (MessageBoxW(NULL, windowsMessage.c_str(), windowsTitle.c_str(), windowsType))
+    {
+        case IDOK:
+            return SDR_OK;
+        case IDCANCEL:
+            return SDR_CANCEL;
+        case IDYES:
+            return SDR_YES;
+        case IDNO:
+            return SDR_NO;
+        default:
+            break;
+    }
+
+    return SDR_OK;
+}
+
+
+void GetCurrentTimeStamp_Windows(SystemTimeStamp *stamp)
+{
+    GetSystemTimeAsFileTime(&stamp->fileTime);
+}
+
+long long GetTimeStampExactResolution_Windows()
+{
+    return 100ll;
+}
+
+long long TimeStampExactDiff_Windows(SystemTimeStamp *before, SystemTimeStamp *after)
+{
+    long long tH = (1ll << 32) * (after->fileTime.dwHighDateTime - before->fileTime.dwHighDateTime);
+    long long tL = after->fileTime.dwLowDateTime - before->fileTime.dwLowDateTime;
+    return (tH + tL) * 100ll;
+}
diff --git a/src/app/system_windows.h b/src/app/system_windows.h
index c9743e6..804d064 100644
--- a/src/app/system_windows.h
+++ b/src/app/system_windows.h
@@ -20,20 +20,11 @@
  * \brief Windows-specific implementation of system functions
  */
 
-/* NOTE: code is contained in this header;
- * there is no separate .cpp module for simplicity */
+#include "app/system.h"
 
 #include <windows.h>
 
 
-std::string UTF8_Encode_Windows(const std::wstring &wstr);
-std::wstring UTF8_Decode_Windows(const std::string &str);
-SystemDialogResult SystemDialog_Windows(SystemDialogType type, const std::string& title, const std::string& message);
-
-void GetCurrentTimeStamp_Windows(SystemTimeStamp *stamp);
-long long GetTimeStampExactResolution_Windows();
-long long TimeStampExactDiff_Windows(SystemTimeStamp *before, SystemTimeStamp *after);
-
 struct SystemTimeStamp
 {
     FILETIME fileTime;
@@ -44,82 +35,10 @@ struct SystemTimeStamp
     }
 };
 
+std::string UTF8_Encode_Windows(const std::wstring &wstr);
+std::wstring UTF8_Decode_Windows(const std::string &str);
+SystemDialogResult SystemDialog_Windows(SystemDialogType type, const std::string& title, const std::string& message);
 
-// Convert a wide Unicode string to an UTF8 string
-std::string UTF8_Encode_Windows(const std::wstring &wstr)
-{
-    int size_needed = WideCharToMultiByte(CP_UTF8, 0, &wstr[0], static_cast<int>(wstr.size()), NULL, 0, NULL, NULL);
-    std::string strTo(size_needed, 0);
-    WideCharToMultiByte(CP_UTF8, 0, &wstr[0], static_cast<int>(wstr.size()), &strTo[0], size_needed, NULL, NULL);
-    return strTo;
-}
-
-// Convert an UTF8 string to a wide Unicode String
-std::wstring UTF8_Decode_Windows(const std::string &str)
-{
-    int size_needed = MultiByteToWideChar(CP_UTF8, 0, &str[0], static_cast<int>(str.size()), NULL, 0);
-    std::wstring wstrTo(size_needed, 0);
-    MultiByteToWideChar(CP_UTF8, 0, &str[0], static_cast<int>(str.size()), &wstrTo[0], size_needed);
-    return wstrTo;
-}
-
-SystemDialogResult SystemDialog_Windows(SystemDialogType type, const std::string& title, const std::string& message)
-{
-    unsigned int windowsType = 0;
-    std::wstring windowsMessage = UTF8_Decode_Windows(message);
-    std::wstring windowsTitle = UTF8_Decode_Windows(title);
-
-    switch (type)
-    {
-        case SDT_INFO:
-        default:
-            windowsType = MB_ICONINFORMATION|MB_OK;
-            break;
-        case SDT_WARNING:
-            windowsType = MB_ICONWARNING|MB_OK;
-            break;
-        case SDT_ERROR:
-            windowsType = MB_ICONERROR|MB_OK;
-            break;
-        case SDT_YES_NO:
-            windowsType = MB_ICONQUESTION|MB_YESNO;
-            break;
-        case SDT_OK_CANCEL:
-            windowsType = MB_ICONWARNING|MB_OKCANCEL;
-            break;
-    }
-
-    switch (MessageBoxW(NULL, windowsMessage.c_str(), windowsTitle.c_str(), windowsType))
-    {
-        case IDOK:
-            return SDR_OK;
-        case IDCANCEL:
-            return SDR_CANCEL;
-        case IDYES:
-            return SDR_YES;
-        case IDNO:
-            return SDR_NO;
-        default:
-            break;
-    }
-
-    return SDR_OK;
-}
-
-
-void GetCurrentTimeStamp_Windows(SystemTimeStamp *stamp)
-{
-    GetSystemTimeAsFileTime(&stamp->fileTime);
-}
-
-long long GetTimeStampExactResolution_Windows()
-{
-    return 100ll;
-}
-
-long long TimeStampExactDiff_Windows(SystemTimeStamp *before, SystemTimeStamp *after)
-{
-    long long tH = (1ll << 32) * (after->fileTime.dwHighDateTime - before->fileTime.dwHighDateTime);
-    long long tL = after->fileTime.dwLowDateTime - before->fileTime.dwLowDateTime;
-    return (tH + tL) * 100ll;
-}
+void GetCurrentTimeStamp_Windows(SystemTimeStamp *stamp);
+long long GetTimeStampExactResolution_Windows();
+long long TimeStampExactDiff_Windows(SystemTimeStamp *before, SystemTimeStamp *after);
diff --git a/test/envs/opengl/CMakeLists.txt b/test/envs/opengl/CMakeLists.txt
index 3de5466..d6c3a37 100644
--- a/test/envs/opengl/CMakeLists.txt
+++ b/test/envs/opengl/CMakeLists.txt
@@ -2,6 +2,14 @@ set(SRC_DIR ${colobot_SOURCE_DIR}/src)
 
 configure_file(${SRC_DIR}/common/config.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/common/config.h)
 
+# Platform-dependent implementation of system.h
+if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+    set(SYSTEM_CPP_MODULE "system_windows.cpp")
+elseif(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+    set(SYSTEM_CPP_MODULE "system_linux.cpp")
+else()
+    set(SYSTEM_CPP_MODULE "system_other.cpp")
+endif()
 
 set(TEXTURE_SOURCES
 ${SRC_DIR}/graphics/opengl/gldevice.cpp
@@ -17,6 +25,7 @@ ${SRC_DIR}/common/logger.cpp
 ${SRC_DIR}/common/image.cpp
 ${SRC_DIR}/common/stringutils.cpp
 ${SRC_DIR}/app/system.cpp
+${SRC_DIR}/app/${SYSTEM_CPP_MODULE}
 model_test.cpp
 )
 
@@ -25,6 +34,7 @@ ${SRC_DIR}/graphics/opengl/gldevice.cpp
 ${SRC_DIR}/common/logger.cpp
 ${SRC_DIR}/common/image.cpp
 ${SRC_DIR}/app/system.cpp
+${SRC_DIR}/app/${SYSTEM_CPP_MODULE}
 transform_test.cpp
 )
 
@@ -33,6 +43,7 @@ ${SRC_DIR}/graphics/opengl/gldevice.cpp
 ${SRC_DIR}/common/logger.cpp
 ${SRC_DIR}/common/image.cpp
 ${SRC_DIR}/app/system.cpp
+${SRC_DIR}/app/${SYSTEM_CPP_MODULE}
 light_test.cpp
 )
 
diff --git a/test/unit/CMakeLists.txt b/test/unit/CMakeLists.txt
index 575f5c0..34027b8 100644
--- a/test/unit/CMakeLists.txt
+++ b/test/unit/CMakeLists.txt
@@ -15,10 +15,20 @@ endif()
 # Configure file
 configure_file(${SRC_DIR}/common/config.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/common/config.h)
 
+# Platform-dependent implementation of system.h
+if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+    set(SYSTEM_CPP_MODULE "system_windows.cpp")
+elseif(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+    set(SYSTEM_CPP_MODULE "system_linux.cpp")
+else()
+    set(SYSTEM_CPP_MODULE "system_other.cpp")
+endif()
+
 # Code sources
 set(COLOBOT_SOURCES
 ${SRC_DIR}/app/app.cpp
 ${SRC_DIR}/app/system.cpp
+${SRC_DIR}/app/${SYSTEM_CPP_MODULE}
 ${SRC_DIR}/common/event.cpp
 ${SRC_DIR}/common/image.cpp
 ${SRC_DIR}/common/iman.cpp
@@ -159,12 +169,24 @@ if (${OPENAL_SOUND})
     endif()
 endif()
 
+
+# Platform-dependent tests
+if (${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+    #TODO: set(PLATFORM_TESTS app/system_windows_test.cpp)
+elseif(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+    set(PLATFORM_TESTS app/system_linux_test.cpp)
+else()
+    #TODO: set(PLATFORM_TESTS app/system_other_test.cpp)
+endif()
+
+# Tests
 set(UT_SOURCES
 main.cpp
 graphics/engine/lightman_test.cpp
 math/geometry_test.cpp
 math/matrix_test.cpp
 math/vector_test.cpp
+${PLATFORM_TESTS}
 )
 
 include_directories(
diff --git a/test/unit/app/system_linux_test.cpp b/test/unit/app/system_linux_test.cpp
new file mode 100644
index 0000000..fe89399
--- /dev/null
+++ b/test/unit/app/system_linux_test.cpp
@@ -0,0 +1,51 @@
+#include "app/system.h"
+#include "app/system_linux.h"
+
+#include <gtest/gtest.h>
+
+TEST(SystemLinuxTest, TimeStampDiff)
+{
+    const long long SEC = 1000000000;
+
+    SystemTimeStamp before, after;
+
+    before.clockTime.tv_sec = 1;
+    before.clockTime.tv_nsec = 100;
+
+    after.clockTime.tv_sec = 1;
+    after.clockTime.tv_nsec = 900;
+
+    long long tDiff = TimeStampExactDiff_Linux(&before, &after);
+    EXPECT_EQ( 800, tDiff);
+
+    tDiff = TimeStampExactDiff_Linux(&after, &before);
+    EXPECT_EQ(-800, tDiff);
+
+    // -------
+
+    before.clockTime.tv_sec = 2;
+    before.clockTime.tv_nsec = 200;
+
+    after.clockTime.tv_sec = 3;
+    after.clockTime.tv_nsec = 500;
+
+    tDiff = TimeStampExactDiff_Linux(&before, &after);
+    EXPECT_EQ( SEC + 300, tDiff);
+
+    tDiff = TimeStampExactDiff_Linux(&after, &before);
+    EXPECT_EQ(-SEC - 300, tDiff);
+
+    // -------
+
+    before.clockTime.tv_sec = 3;
+    before.clockTime.tv_nsec = 200;
+
+    after.clockTime.tv_sec = 4;
+    after.clockTime.tv_nsec = 100;
+
+    tDiff = TimeStampExactDiff_Linux(&before, &after);
+    EXPECT_EQ( SEC - 100, tDiff);
+
+    tDiff = TimeStampExactDiff_Linux(&after, &before);
+    EXPECT_EQ(-SEC + 100, tDiff);
+}