From 0c509f61a3edcb2bc4d3f305def55e3d4bd3c34f Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Mon, 3 Jul 2017 08:34:49 -0700
Subject: [PATCH] use pointers in directory

---
 pitfall/fontkit/directory.rkt | 51 ++++++++++-------------------------
 pitfall/fontkit/subset.rkt    |  2 +-
 2 files changed, 15 insertions(+), 38 deletions(-)

diff --git a/pitfall/fontkit/directory.rkt b/pitfall/fontkit/directory.rkt
index a86ddcaf..c755dfe9 100644
--- a/pitfall/fontkit/directory.rkt
+++ b/pitfall/fontkit/directory.rkt
@@ -11,7 +11,7 @@ https://github.com/mbutterick/fontkit/blob/master/src/tables/directory.js
 (define TableEntry (+Struct
                     (dictify 'tag (+String 4)
                              'checkSum uint32be
-                             'offset uint32be
+                             'offset (+Pointer uint32be 'void (mhash 'type 'global))
                              'length uint32be)))
 
 ;; for stupid tags like 'cvt '
@@ -29,53 +29,30 @@ https://github.com/mbutterick/fontkit/blob/master/src/tables/directory.js
     this-res)
 
   (define/override (preEncode this-val stream)
-    (define preamble-length 12)
-    (define table-header-size (+ preamble-length
-                                 (* (length (hash-keys (· this-val tables))) (send TableEntry size))))
+    (define tables (for/list ([(tag table) (in-hash (· this-val tables))])
+                             (mhash 'tag (unescape-tag tag)
+                                    'checkSum 0
+                                    'offset (+VoidPointer (hash-ref table-codecs tag) table)
+                                    'length (send (hash-ref table-codecs tag) size table))))
 
-    (define-values (table-headers table-datas _)
-      (for/lists (ths tds lens)
-                 ([(tag table) (in-hash (· this-val tables))])
-
-                 (define table-data
-                   (let ([es (+EncodeStream)])
-                     (send (hash-ref table-codecs tag) encode es table)
-                     (send es dump)))
-
-                 (define table-header (mhash
-                                       'tag (unescape-tag tag)
-                                       'checkSum 0
-                                       'offset (apply + (cons table-header-size lens))
-                                       'length (bytes-length table-data)))
-        
-                 (values table-header table-data (bytes-length table-data))))
-
-
-    (define numTables (length table-headers))
+    (define numTables (length tables))
     (define searchRange (* (floor (log numTables 2)) 16))
     
     (hash-set*! this-val
                 'tag "true"
                 'numTables numTables
-                'tables table-headers
+                'tables tables
                 'searchRange searchRange
                 'entrySelector (floor (/ searchRange (log 2)))
-                'rangeShift (- (* numTables 16) searchRange)
-                'data table-datas)))
+                'rangeShift (- (* numTables 16) searchRange))))
 
-(define directory-common-dict (dictify 'tag (+String 4)
+(define Directory (+RDirectory (dictify 'tag (+String 4)
                                        'numTables uint16be
                                        'searchRange uint16be
                                        'entrySelector uint16be
                                        'rangeShift uint16be
-                                       'tables (+Array TableEntry 'numTables)))
-
-(define Directory (+RDirectory directory-common-dict))
+                                       'tables (+Array TableEntry 'numTables))))
                             
-;; we don't know what tables we might get
-;; so we represent as generic Buffer type,
-;; and convert the tables to bytes manually in preEncode
-(define EncodableDirectory (+RDirectory (append directory-common-dict (list (cons 'data (+Array (+RBuffer)))))))
 
 (define (directory-decode ip [options (mhash)])
   (send Directory decode (+DecodeStream (port->bytes ip))))
@@ -84,6 +61,6 @@ https://github.com/mbutterick/fontkit/blob/master/src/tables/directory.js
   (directory-decode (open-input-file ps)))
 
 #;(test-module
- (define ip (open-input-file charter-path))
- (define decoded-dir (deserialize (read (open-input-file charter-directory-path))))
- (check-equal? (directory-decode ip) decoded-dir))
\ No newline at end of file
+   (define ip (open-input-file charter-path))
+   (define decoded-dir (deserialize (read (open-input-file charter-directory-path))))
+   (check-equal? (directory-decode ip) decoded-dir))
\ No newline at end of file
diff --git a/pitfall/fontkit/subset.rkt b/pitfall/fontkit/subset.rkt
index 4dbe3c34..15c78b7d 100644
--- a/pitfall/fontkit/subset.rkt
+++ b/pitfall/fontkit/subset.rkt
@@ -124,7 +124,7 @@ https://github.com/mbutterick/fontkit/blob/master/src/subset/TTFSubset.js
   (define hhea (cloneDeep (send (· this font hhea) kv)))
   (dict-set! hhea 'numberOfMetrics (length (· this hmtx metrics)))
 
-  (send EncodableDirectory encode stream
+  (send Directory encode stream
         (mhash 'tables
                (mhash
                 'head head