Add new path API for os2

core/os/os2/path_windows.odin

@@ -1,8 +1,10 @@
 #+private
 package os2
 
-import win32 "core:sys/windows"
+import "base:intrinsics"
 import "base:runtime"
+import "core:strings"
+import win32 "core:sys/windows"
 
 _Path_Separator        :: '\\'
 _Path_Separator_String :: "\\"
@@ -217,7 +219,7 @@ _fix_long_path_internal :: proc(path: string) -> string {
 		return path
 	}
 
-	if !_is_abs(path) { // relative path
+	if !_is_absolute_path(path) { // relative path
 		return path
 	}
 
@@ -257,3 +259,93 @@ _fix_long_path_internal :: proc(path: string) -> string {
 
 	return string(path_buf[:w])
 }
+
+_are_paths_identical :: strings.equal_fold
+
+_clean_path_handle_start :: proc(path: string, buffer: []u8) -> (rooted: bool, start: int) {
+	// Preserve rooted paths.
+	start = _volume_name_len(path)
+	if start > 0 {
+		rooted = true
+		if len(path) > start && _is_path_separator(path[start]) {
+			// Take `C:` to `C:\`.
+			start += 1
+		}
+		intrinsics.mem_copy_non_overlapping(raw_data(buffer), raw_data(path), start)
+	}
+	return
+}
+
+_is_absolute_path :: proc(path: string) -> bool {
+	if _is_reserved_name(path) {
+		return true
+	}
+	l := _volume_name_len(path)
+	if l == 0 {
+		return false
+	}
+
+	path := path
+	path = path[l:]
+	if path == "" {
+		return false
+	}
+	return _is_path_separator(path[0])
+}
+
+_get_absolute_path :: proc(path: string, allocator: runtime.Allocator) -> (absolute_path: string, err: Error) {
+	rel := path
+	if rel == "" {
+		rel = "."
+	}
+	TEMP_ALLOCATOR_GUARD()
+	rel_utf16 := win32.utf8_to_utf16(rel, temp_allocator())
+	n := win32.GetFullPathNameW(raw_data(rel_utf16), 0, nil, nil)
+	if n == 0 {
+		return "", Platform_Error(win32.GetLastError())
+	}
+
+	buf := make([]u16, n, temp_allocator()) or_return
+	n = win32.GetFullPathNameW(raw_data(rel_utf16), u32(n), raw_data(buf), nil)
+	if n == 0 {
+		return "", Platform_Error(win32.GetLastError())
+	}
+
+	return win32.utf16_to_utf8(buf, allocator)
+}
+
+_get_relative_path_handle_start :: proc(base, target: string) -> bool {
+	base_root   := base[:_volume_name_len(base)]
+	target_root := target[:_volume_name_len(target)]
+	return strings.equal_fold(base_root, target_root)
+}
+
+_get_common_path_len :: proc(base, target: string) -> int {
+	i := 0
+	end := min(len(base), len(target))
+	for j in 0..=end {
+		if j == end || _is_path_separator(base[j]) {
+			if strings.equal_fold(base[i:j], target[i:j]) {
+				i = j
+			} else {
+				break
+			}
+		}
+	}
+	return i
+}
+
+_split_path :: proc(path: string) -> (dir, file: string) {
+	vol_len := _volume_name_len(path)
+
+	i := len(path) - 1
+	for i >= vol_len && !_is_path_separator(path[i]) {
+		i -= 1
+	}
+	if i == vol_len {
+		return path[:i+1], path[i+1:]
+	} else if i > vol_len {
+		return path[:i], path[i+1:]
+	}
+	return "", path
+}