[var] Implement MVAR table

Unhooked. Untested.

src/Makefile.sources

@@ -112,6 +112,7 @@ HB_OT_sources = \
 	hb-ot-var-avar-table.hh \
 	hb-ot-var-fvar-table.hh \
 	hb-ot-var-hvar-table.hh \
+	hb-ot-var-mvar-table.hh \
 	$(NULL)
 
 HB_OT_headers = \

src/hb-font.cc

@@ -1627,7 +1627,7 @@ hb_font_set_var_coords_normalized (hb_font_t *font,
 }
 
 /**
- * hb_font_set_var_coords_normalized:
+ * hb_font_get_var_coords_normalized:
  *
  * Return value is valid as long as variation coordinates of the font
  * are not modified.

src/hb-ot-var-mvar-table.hh

@@ -0,0 +1,110 @@
+/*
+ * Copyright © 2017  Google, Inc.
+ *
+ *  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.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#ifndef HB_OT_VAR_MVAR_TABLE_HH
+#define HB_OT_VAR_MVAR_TABLE_HH
+
+#include "hb-ot-layout-common-private.hh"
+
+
+namespace OT {
+
+
+struct VariationValueRecord
+{
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this));
+  }
+
+  public:
+  Tag		valueTag;	/* Four-byte tag identifying a font-wide measure. */
+  ULONG		varIdx;		/* Outer/inner index into VariationStore item. */
+
+  public:
+  DEFINE_SIZE_STATIC (8);
+};
+
+
+/*
+ * MVAR -- Metrics Variations Table
+ */
+
+#define HB_OT_TAG_MVAR HB_TAG('M','V','A','R')
+
+struct MVAR
+{
+  static const hb_tag_t tableTag	= HB_OT_TAG_MVAR;
+
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (version.sanitize (c) &&
+		  likely (version.major == 1) &&
+		  c->check_struct (this) &&
+		  valueRecordSize >= VariationValueRecord::static_size &&
+		  varStore.sanitize (c, this) &&
+		  c->check_array (values, valueRecordSize, valueRecordCount));
+  }
+
+  inline float get_var (hb_tag_t tag,
+			int *coords, unsigned int coord_count) const
+  {
+    const VariationValueRecord *record;
+    record = (VariationValueRecord *) bsearch (&tag, values,
+					       valueRecordCount, valueRecordSize,
+					       (hb_compare_func_t) tag_compare);
+    if (!record)
+      return 0.;
+
+    return (this+varStore).get_delta (record->varIdx, coords, coord_count);
+  }
+
+protected:
+  static inline int tag_compare (const hb_tag_t *a, const Tag *b)
+  { return b->cmp (*a); }
+
+  protected:
+  FixedVersion<>version;	/* Version of the metrics variation table
+				 * initially set to 0x00010000u */
+  USHORT	reserved;	/* Not used; set to 0. */
+  USHORT	valueRecordSize;/* The size in bytes of each value record —
+				 * must be greater than zero. */
+  USHORT	valueRecordCount;/* The number of value records — may be zero. */
+  OffsetTo<VariationStore>
+		varStore;	/* Offset to item variation store table. */
+  BYTE		values[VAR];	/* Array of value records. The records must be
+				 * in binary order of their valueTag field. */
+
+  public:
+  DEFINE_SIZE_ARRAY (12, values);
+};
+
+} /* namespace OT */
+
+
+#endif /* HB_OT_VAR_MVAR_TABLE_HH */

src/hb-ot-var.cc

@@ -29,6 +29,7 @@
 #include "hb-ot-layout-private.hh"
 #include "hb-ot-var-avar-table.hh"
 #include "hb-ot-var-fvar-table.hh"
+#include "hb-ot-var-mvar-table.hh"
 #include "hb-ot-var.h"
 
 HB_SHAPER_DATA_ENSURE_DECLARE(ot, face)