[gasp] Implement the table parsing

May or may not be used in https://github.com/harfbuzz/harfbuzz/pull/1432

src/Makefile.sources

@@ -59,6 +59,7 @@ HB_BASE_sources = \
 	hb-ot-face.cc \
 	hb-ot-face.hh \
 	hb-ot-font.cc \
+	hb-ot-gasp-table.hh \
 	hb-ot-glyf-table.hh \
 	hb-ot-hdmx-table.hh \
 	hb-ot-head-table.hh \

src/hb-ot-gasp-table.hh

@@ -0,0 +1,84 @@
+/*
+ * 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_OT_GASP_TABLE_HH
+#define HB_OT_GASP_TABLE_HH
+
+#include "hb-open-type.hh"
+#include "hb-ot-hhea-table.hh"
+#include "hb-ot-os2-table.hh"
+#include "hb-ot-var-hvar-table.hh"
+
+/*
+ * gasp -- Grid-fitting and Scan-conversion Procedure
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/gasp
+ */
+#define HB_OT_TAG_gasp HB_TAG('g','a','s','p')
+
+
+namespace OT {
+
+struct GaspRange
+{
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this));
+  }
+
+  public:
+  HBUINT16 	rangeMaxPPEM;	/* Upper limit of range, in PPEM */
+  HBUINT16 	rangeGaspBehavior;
+				/* Flags describing desired rasterizer behavior. */
+  public:
+  DEFINE_SIZE_STATIC (4);
+};
+
+struct gasp
+{
+  enum { tableTag = HB_OT_TAG_gasp };
+
+  inline const GaspRange &get_gasp_range (unsigned int i) const
+  { return gaspRanges[i]; }
+
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  gaspRanges.sanitize (c));
+  }
+
+  protected:
+  HBUINT16	version;	/* Version number (set to 1) */
+  ArrayOf<GaspRange>
+		gaspRanges;	/* Number of records to follow
+				 * Sorted by ppem */
+  public:
+  DEFINE_SIZE_ARRAY (4, gaspRanges);
+};
+
+} /* namespace OT */
+
+
+#endif /* HB_OT_GASP_TABLE_HH */

src/hb-ot-layout.cc

@@ -35,11 +35,12 @@
 #include "hb-map.hh"
 
 #include "hb-ot-kern-table.hh"
+#include "hb-ot-gasp-table.hh" // Just so we compile it; unused otherwise.
 #include "hb-ot-layout-gdef-table.hh"
 #include "hb-ot-layout-gsub-table.hh"
 #include "hb-ot-layout-gpos-table.hh"
-#include "hb-ot-layout-base-table.hh" // Just so we compile it; unused otherwise
+#include "hb-ot-layout-base-table.hh" // Just so we compile it; unused otherwise.
-#include "hb-ot-layout-jstf-table.hh" // Just so we compile it; unused otherwise
+#include "hb-ot-layout-jstf-table.hh" // Just so we compile it; unused otherwise.
 #include "hb-ot-name-table.hh"
 #include "hb-ot-os2-table.hh"