Add new path API for os2

core/os/os2/path_posixfs.odin

@@ -0,0 +1,78 @@
+#+private
+#+build linux, darwin, netbsd, freebsd, openbsd, wasi
+package os2
+
+// This implementation is for all systems that have POSIX-compliant filesystem paths.
+
+import "base:runtime"
+import "core:strings"
+import "core:sys/posix"
+
+_are_paths_identical :: proc(a, b: string) -> (identical: bool) {
+	return a == b
+}
+
+_clean_path_handle_start :: proc(path: string, buffer: []u8) -> (rooted: bool, start: int) {
+	// Preserve rooted paths.
+	if _is_path_separator(path[0]) {
+		rooted = true
+		buffer[0] = _Path_Separator
+		start = 1
+	}
+	return
+}
+
+_is_absolute_path :: proc(path: string) -> bool {
+	return len(path) > 0 && _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_cstr := strings.clone_to_cstring(rel, temp_allocator())
+	path_ptr := posix.realpath(rel_cstr, nil)
+	if path_ptr == nil {
+		return "", Platform_Error(posix.errno())
+	}
+	defer posix.free(path_ptr)
+
+	path_str := strings.clone(string(path_ptr), allocator)
+	return path_str, nil
+}
+
+_get_relative_path_handle_start :: proc(base, target: string) -> bool {
+	base_rooted   := len(base)   > 0 && _is_path_separator(base[0])
+	target_rooted := len(target) > 0 && _is_path_separator(target[0])
+	return base_rooted == target_rooted
+}
+
+_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 base[i:j] == target[i:j] {
+				i = j
+			} else {
+				break
+			}
+		}
+	}
+	return i
+}
+
+_split_path :: proc(path: string) -> (dir, file: string) {
+	i := len(path) - 1
+	for i >= 0 && !_is_path_separator(path[i]) {
+		i -= 1
+	}
+	if i == 0 {
+		return path[:i+1], path[i+1:]
+	} else if i > 0 {
+		return path[:i], path[i+1:]
+	}
+	return "", path
+}