[aat] Implement feat table parsing (#947)

src/Makefile.sources

@@ -86,10 +86,11 @@ HB_OT_sources = \
 	hb-aat-layout-kerx-table.hh \
 	hb-aat-layout-morx-table.hh \
 	hb-aat-layout-trak-table.hh \
+	hb-aat-layout-private.hh \
+	hb-aat-feat-table.hh \
 	hb-aat-fmtx-table.hh \
 	hb-aat-gcid-table.hh \
 	hb-aat-ltag-table.hh \
-	hb-aat-layout-private.hh \
 	hb-ot-font.cc \
 	hb-ot-layout.cc \
 	hb-ot-layout-base-table.hh \

src/hb-aat-feat-table.hh

+/*
+ * Copyright © 2018  Ebrahim Byagowi
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+
+#ifndef HB_AAT_FEAT_TABLE_HH
+#define HB_AAT_FEAT_TABLE_HH
+
+#include "hb-aat-layout-common-private.hh"
+
+#define HB_AAT_TAG_feat HB_TAG('f','e','a','t')
+
+
+namespace AAT {
+
+struct FeatureName {
+
+  inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+      (base+settingTable).sanitize (c, nSettings, base));
+  }
+
+  enum {
+    Exclusive = 0x8000,		/* If set, the feature settings are mutually exclusive. */
+    NotDefault = 0x4000,	/* If clear, then the setting with an index of 0 in
+				 * the setting name array for this feature should
+				 * be taken as the default for the feature
+				 * (if one is required). If set, then bits 0-15 of this
+				 * featureFlags field contain the index of the setting
+				 * which is to be taken as the default. */
+    IndexMask = 0x00FF		/* If bits 30 and 31 are set, then these sixteen bits
+				 * indicate the index of the setting in the setting name
+				 * array for this feature which should be taken
+				 * as the default. */
+  };
+
+  struct SettingName
+  {
+    inline bool sanitize (hb_sanitize_context_t *c, const void *base HB_UNUSED) const
+    {
+      TRACE_SANITIZE (this);
+      return_trace (c->check_struct (this) &&
+	nameIndex > 255 && nameIndex < 32768);
+    }
+
+    protected:
+    HBUINT16	setting;	/* The setting. */
+    NameID	nameIndex;	/* The name table index for the setting's name.
+				 * The nameIndex must be greater than 255 and less than 32768. */
+    public:
+    DEFINE_SIZE_STATIC (4);
+  };
+
+  protected:
+  HBUINT16	feature;	/* Feature type. */
+  HBUINT16	nSettings;	/* The number of records in the setting name array. */
+  LOffsetTo<UnsizedArrayOf<SettingName> >
+	settingTable;		/* Offset in bytes from the beginning of this table to
+				 * this feature's setting name array. The actual type of
+				 * record this offset refers to will depend on the
+				 * exclusivity value, as described below. */
+  HBUINT16	featureFlags;	/* Single-bit flags associated with the feature type. */
+  HBINT16	nameIndex;	/* The name table index for the feature's name.
+				 * This index has values greater than 255 and
+				 * less than 32768. */
+  public:
+  DEFINE_SIZE_STATIC (12);
+};
+
+/*
+ * feat -- Feature name
+ * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6fmtx.html
+ */
+
+struct feat
+{
+  static const hb_tag_t tableTag = HB_AAT_TAG_feat;
+
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+      names.sanitize (c, featureNameCount, this));
+  }
+
+  protected:
+  FixedVersion<>version;	/* Version number of the feature name table
+				 * (0x00010000 for the current version). */
+  HBUINT16	featureNameCount;
+				/* The number of entries in the feature name array. */
+  HBUINT16	reserved1;	/* Reserved (set to zero). */
+  HBUINT32	reserved2;	/* Reserved (set to zero). */
+  UnsizedArrayOf<FeatureName>
+		names;		/* The feature name array. */
+  public:
+  DEFINE_SIZE_STATIC (24);
+};
+
+} /* namespace AAT */
+
+#endif /* HB_AAT_FEAT_TABLE_HH */

src/hb-aat-layout.cc

@@ -35,6 +35,7 @@
 #include "hb-aat-layout-kerx-table.hh"
 #include "hb-aat-layout-morx-table.hh"
 #include "hb-aat-layout-trak-table.hh"
+#include "hb-aat-feat-table.hh" // Just so we compile it; unused otherwise.
 #include "hb-aat-fmtx-table.hh" // Just so we compile it; unused otherwise.
 #include "hb-aat-gcid-table.hh" // Just so we compile it; unused otherwise.
 #include "hb-aat-ltag-table.hh" // Just so we compile it; unused otherwise.