Fixed loading of tilesets and images from tilemaps to correctly use relative paths.

src/util.c

@@ -1,5 +1,6 @@
 #include <limits.h>
 #include <stdlib.h>
+#include <errno.h>
 
 #include <SDL3/SDL.h>
 #include <SDL3_image/SDL_image.h>
@@ -9,6 +10,72 @@
 #include <akgl/heap.h>
 #include <akgl/registry.h>
 #include <akgl/game.h>
+#include <akgl/staticstring.h>
+
+#include <akstdlib.h>
+
+akerr_ErrorContext *akgl_path_relative_root(char *root, char *path, akgl_String *dst)
+{
+    PREPARE_ERROR(e);
+    akgl_String *pathbuf;
+    akgl_String *strbuf;
+    char *result;
+    int rootlen;
+    int pathlen;
+    int count;
+    
+    FAIL_ZERO_RETURN(e, root, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, path, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, dst, AKERR_NULLPOINTER, "NULL argument");
+
+    PASS(e, akgl_heap_next_string(&strbuf));
+    PASS(e, akgl_heap_next_string(&pathbuf));
+    
+    ATTEMPT {
+	// Is it relative to the root?
+	rootlen = strlen(root);
+	pathlen = strlen(path);
+	if ( (rootlen + pathlen) >= AKGL_MAX_STRING_LENGTH ) {
+	    FAIL_RETURN(e, AKERR_OUTOFBOUNDS, "Total path length (%d) is greater than maximum akgl_String length (%d)", (rootlen + pathlen), AKGL_MAX_STRING_LENGTH);
+	}
+	CATCH(e, aksl_sprintf(&count, (char *)&pathbuf->data, "%s/%s", root, path));
+	CATCH(e, aksl_realpath((char *)&pathbuf->data, (char *)&strbuf->data));
+	CATCH(e, akgl_string_copy(strbuf, dst, 0)); 
+    } CLEANUP {
+	IGNORE(akgl_heap_release_string(strbuf));
+	IGNORE(akgl_heap_release_string(pathbuf));
+    } PROCESS(e) {
+    } FINISH(e, true);
+    SUCCEED_RETURN(e);
+}
+
+akerr_ErrorContext *akgl_path_relative(char *root, char *path, akgl_String *dst)
+{
+    PREPARE_ERROR(e);
+    akgl_String *strbuf;
+    char *result;
+    
+    FAIL_ZERO_RETURN(e, root, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, path, AKERR_NULLPOINTER, "NULL argument");
+    FAIL_ZERO_RETURN(e, dst, AKERR_NULLPOINTER, "NULL argument");
+
+    PASS(e, akgl_heap_next_string(&strbuf));
+    
+    ATTEMPT {
+	// Is path relative to our current working directory?
+	CATCH(e, aksl_realpath(path, (char *)&strbuf->data));
+	// Yes it is. strbuf->data contains the absolute path.
+	CATCH(e, akgl_string_copy(strbuf, dst, 0)); 
+    } CLEANUP {
+	IGNORE(akgl_heap_release_string(strbuf));
+    } PROCESS(e) {
+    } HANDLE(e, ENOENT) {
+	// Path is not relative to our current working directory
+	// Noop - execution proceeds after the break
+	return akgl_path_relative_root(root, path, dst);
+    } FINISH(e, true);
+    SUCCEED_RETURN(e);
+}
 
 akerr_ErrorContext *akgl_rectangle_points(RectanglePoints *dest, SDL_FRect *rect)
 {