Change string->nfc to return immutable value, and optimize a bit.

diff --git a/src/runtime/ustring.scm b/src/runtime/ustring.scm
index ee7c65f6dc7f43edb04c9792f84ff606dbcb8c6c..521c74d9092bd44195cfff7b1c613940c630e9ab 100644 (file)
--- a/src/runtime/ustring.scm
+++ b/src/runtime/ustring.scm
@@ -474,6 +474,16 @@ USA.
     ((1) (max-loop cp1-ref))
     ((2) (max-loop cp2-ref))
     (else (max-loop cp3-ref))))
+
+(define (%string->immutable string)
+  (unpack-slice string
+    (lambda (string* start end)
+      (let ((result
+            (immutable-ustring-allocate
+             (fix:- end start)
+             (%general-max-cp string* start end))))
+       (%general-copy! result 0 string* start end)
+       result))))
 \f
 ;;;; Streaming builder
 
@@ -818,26 +828,6 @@ USA.
 \f
 ;;;; Normalization
 
-(define (string->nfd string)
-  (if (string-in-nfd? string)
-      (if (and (ustring? string) (not (ustring-mutable? string)))
-         string
-         (unpack-slice string
-           (lambda (string* start end)
-             (let ((result
-                    (immutable-ustring-allocate
-                     (fix:- end start)
-                     (%general-max-cp string* start end))))
-               (%general-copy! result 0 string* start end)
-               (ustring-in-nfd! result)
-               result))))
-      (canonical-decomposition&ordering string
-       (lambda (string* n max-cp)
-         (let ((result (immutable-ustring-allocate n max-cp)))
-           (%general-copy! result 0 string* 0 n)
-           (ustring-in-nfd! result)
-           result)))))
-
 (define (string-in-nfd? string)
   (cond ((or (legacy-string? string) (ustring? string))
         (if (ustring-mutable? string)
@@ -848,14 +838,6 @@ USA.
        (else
         (error:not-a string? string 'string-in-nfd?))))
 
-(define (string->nfc string)
-  (if (string-in-nfc? string)
-      string
-      (canonical-composition (string->nfd string))))
-
-(define (string->nfc-cf string)
-  (string->nfc (string-foldcase string)))
-
 (define (string-in-nfc? string)
   (cond ((legacy-string? string)
         #t)
@@ -864,9 +846,7 @@ USA.
             (ustring-nfc-qc? string 0 (ustring-length string))
             (ustring-in-nfc? string)))
        ((slice? string)
-        (ustring-nfc-qc? (slice-string string)
-                         (slice-start string)
-                         (slice-end string)))
+        (unpack-slice string ustring-nfc-qc?))
        (else
         (error:not-a string? string 'string-in-nfc?))))
 
@@ -898,6 +878,42 @@ USA.
 (define %ustring-nfc-qc? (string-nqc-loop #x300 char-nfc-quick-check?))
 (define %ustring-nfd-qc? (string-nqc-loop #xC0 char-nfd-quick-check?))
 \f
+(define (string->nfd string)
+  (cond ((and (ustring? string)
+             (ustring-in-nfd? string))
+        string)
+       ((string-in-nfd? string)
+        (let ((result (%string->immutable string)))
+          (ustring-in-nfd! result)
+          result))
+       (else
+        (canonical-decomposition&ordering string
+          (lambda (string* n max-cp)
+            (let ((result (immutable-ustring-allocate n max-cp)))
+              (%general-copy! result 0 string* 0 n)
+              (ustring-in-nfd! result)
+              result))))))
+
+(define (string->nfc string)
+  (cond ((and (ustring? string)
+             (ustring-in-nfc? string))
+        string)
+       ((string-in-nfc? string)
+        (let ((result (%string->immutable string)))
+          (ustring-in-nfc! result)
+          result))
+       (else
+        (canonical-composition
+         (if (string-in-nfd? string)
+             string
+             (canonical-decomposition&ordering string
+               (lambda (string* n max-cp)
+                 (declare (ignore n max-cp))
+                 string*)))))))
+
+(define (string->nfc-cf string)
+  (string->nfc (string-foldcase string)))
+\f
 (define (canonical-decomposition&ordering string k)
   (let ((end (string-length string))
        (builder (make-string-builder 'result 'mutable)))