From 51300868df15467ac754212564eab607377791af Mon Sep 17 00:00:00 2001
From: Philipp <pengel@hs-nb.de>
Date: Sat, 19 Oct 2024 23:43:29 +0200
Subject: [PATCH] Added join function.

---
 src/dm_path.f90     | 30 ++++++++++++++++++++++++++++++
 test/dmtestpath.f90 | 20 ++++++++++++++++++--
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/src/dm_path.f90 b/src/dm_path.f90
index dae3340..c4b3e5e 100644
--- a/src/dm_path.f90
+++ b/src/dm_path.f90
@@ -5,8 +5,38 @@ module dm_path
     implicit none (type, external)
     private
 
+    public :: dm_path_join
     public :: dm_path_parsed
 contains
+    pure function dm_path_join(path1, path2) result(path)
+        !! Joins paths and adds `/` between them.
+        character(len=*), intent(in)  :: path1 !! First path.
+        character(len=*), intent(in)  :: path2 !! Second path.
+        character(len=:), allocatable :: path  !! Joined path.
+
+        integer :: n1, n2
+
+        n1 = len_trim(path1)
+        n2 = len_trim(path2)
+
+        if (n1 == 0 .and. n2 == 0) then
+            path = ''
+            return
+        else if (n1 == 0) then
+            path = path2(:n2)
+            return
+        else if (n2 == 0) then
+            path = path1(:n1)
+            return
+        end if
+
+        if (path1(n1:n1) /= '/' .and. path2(1:1) /= '/') then
+            path = path1(:n1) // '/' // path2(:n2)
+        else
+            path = path1(:n1) // path2(:n2)
+        end if
+    end function dm_path_join
+
     function dm_path_parsed(path) result(parsed)
         !! Returns a parsed path or an empty string on error. The following
         !! format descriptors are allowed:
diff --git a/test/dmtestpath.f90 b/test/dmtestpath.f90
index 3279b91..d16c16d 100644
--- a/test/dmtestpath.f90
+++ b/test/dmtestpath.f90
@@ -8,13 +8,14 @@ program dmtestpath
     implicit none (type, external)
 
     character(len=*), parameter :: TEST_NAME = 'dmtestpath'
-    integer,          parameter :: NTESTS    = 1
+    integer,          parameter :: NTESTS    = 2
 
     type(test_type) :: tests(NTESTS)
     logical         :: stats(NTESTS)
 
     tests = [ &
-        test_type('test01', test01) &
+        test_type('test01', test01), &
+        test_type('test02', test02)  &
     ]
 
     call dm_init()
@@ -35,4 +36,19 @@ logical function test01() result(stat)
 
         stat = TEST_PASSED
     end function test01
+
+    logical function test02() result(stat)
+        stat = TEST_FAILED
+
+        print *, 'Joining paths ...'
+
+        if (dm_path_join('a', 'b')  /= 'a/b') return
+        if (dm_path_join('a/', 'b') /= 'a/b') return
+        if (dm_path_join('a', '/b') /= 'a/b') return
+        if (dm_path_join('a', '')   /= 'a')   return
+        if (dm_path_join('', 'b')   /= 'b')   return
+        if (dm_path_join('', '')    /= '')    return
+
+        stat = TEST_PASSED
+    end function test02
 end program dmtestpath