Add 'is_absolute_path()' function

Also, the 'get_relative_path(pathA, pathB)' function has been made
case-insensitive. This is done to correctly calculate common folders
in case one of the entered paths has a case difference.

Author: Gasparoken

base/fs.cpp

@@ -1,5 +1,5 @@
 // LAF Base Library
-// Copyright (c) 2021-2024 Igara Studio S.A.
+// Copyright (c) 2021-2025 Igara Studio S.A.
 // Copyright (c) 2001-2018 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -35,6 +35,17 @@ const std::string::value_type* path_separators = "\\/";
 const std::string::value_type* path_separators = "/";
 #endif
 
+bool is_absolute_path(const std::string& path)
+{
+#ifdef LAF_WINDOWS
+  return (path.size() > 2 && std::isalpha(path[0]) && path[1] == ':' && path[2] == path_separator)
+         // Network path (UNC)
+         || (path.size() > 1 && path[0] == path_separator && path[1] == path_separator);
+#else
+  return !path.empty() && path[0] == path_separator;
+#endif
+}
+
 void make_all_directories(const std::string& path)
 {
   std::vector<std::string> parts;
@@ -194,7 +205,8 @@ std::string get_relative_path(const std::string& filename, const std::string& ba
   auto itFrom = baseDirs.begin();
   auto itTo = toParts.begin();
 
-  while (itFrom != baseDirs.end() && itTo != toParts.end() && *itFrom == *itTo) {
+  while (itFrom != baseDirs.end() && itTo != toParts.end() &&
+         base::string_to_lower(*itFrom) == base::string_to_lower((*itTo))) {
     ++itFrom;
     ++itTo;
   }

base/fs.h

@@ -1,5 +1,5 @@
 // LAF Base Library
-// Copyright (c) 2020-2024 Igara Studio S.A.
+// Copyright (c) 2020-2025 Igara Studio S.A.
 // Copyright (c) 2001-2018 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -28,6 +28,7 @@ extern const std::string::value_type* path_separators;
 
 bool is_file(const std::string& path);
 bool is_directory(const std::string& path);
+bool is_absolute_path(const std::string& path);
 
 size_t file_size(const std::string& path);
 

base/fs_tests.cpp

@@ -258,6 +258,31 @@ TEST(FS, GetAbsolutePath)
 #endif
 }
 
+TEST(FS, IsAbsolutePath)
+{
+  EXPECT_FALSE(is_absolute_path(""));
+  EXPECT_FALSE(is_absolute_path("a"));
+  EXPECT_FALSE(is_absolute_path("./a"));
+  EXPECT_FALSE(is_absolute_path("../a"));
+  EXPECT_FALSE(is_absolute_path("."));
+  EXPECT_FALSE(is_absolute_path("./."));
+  EXPECT_FALSE(is_absolute_path("./a/.."));
+  EXPECT_FALSE(is_absolute_path(".\\//."));
+
+#if LAF_WINDOWS
+  EXPECT_TRUE(is_absolute_path("C:\\path\\..\\file"));
+  EXPECT_TRUE(is_absolute_path("\\\\network\\path"));
+  EXPECT_FALSE(is_absolute_path("C:user\\name\\"));
+  EXPECT_FALSE(is_absolute_path("C\\user\\name\\"));
+  EXPECT_FALSE(is_absolute_path("\\user\\path\\"));
+  EXPECT_FALSE(is_absolute_path(".:\\user\\name"));
+  EXPECT_FALSE(is_absolute_path("\\:\\user\\name"));
+#else
+  EXPECT_TRUE(is_absolute_path("/path/../file"));
+  EXPECT_FALSE(is_absolute_path("path/../file"));
+#endif
+}
+
 TEST(FS, GetCanonicalPath)
 {
   const auto cp = get_current_path();

base/fs_unix.h

@@ -1,5 +1,5 @@
 // LAF Base Library
-// Copyright (c) 2021-2024 Igara Studio S.A.
+// Copyright (c) 2021-2025 Igara Studio S.A.
 // Copyright (c) 2001-2018 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -212,9 +212,8 @@ std::string get_canonical_path(const std::string& path)
 
 std::string get_absolute_path(const std::string& path)
 {
-  std::string full = path;
-  if (!full.empty() && full[0] != '/')
-    full = join_path(get_current_path(), full);
+  std::string full(is_absolute_path(path) ?
+                   path : join_path(get_current_path(), path));
   full = normalize_path(full);
   if (!full.empty() && full.back() == path_separator)
     full.erase(full.size() - 1);

base/fs_win32.h

@@ -160,11 +160,8 @@ std::string get_canonical_path(const std::string& path)
 
 std::string get_absolute_path(const std::string& path)
 {
-  std::string full;
-  if (path.size() > 2 && path[1] != ':')
-    full = base::join_path(base::get_current_path(), path);
-  else
-    full = path;
+  std::string full(base::is_absolute_path(path) ?
+                   path : base::join_path(base::get_current_path(), path));
 
   TCHAR buffer[MAX_PATH + 1] = {};
   GetFullPathName(from_utf8(full).c_str(), sizeof(buffer) / sizeof(TCHAR), buffer, nullptr);