[aat] Implement bsln table parsing (#943)

src/Makefile.sources

@@ -82,6 +82,7 @@ HB_OT_sources = \
 	hb-aat-layout.cc \
 	hb-aat-layout-common-private.hh \
 	hb-aat-layout-ankr-table.hh \
+	hb-aat-layout-bsln-table.hh \
 	hb-aat-layout-kerx-table.hh \
 	hb-aat-layout-morx-table.hh \
 	hb-aat-layout-trak-table.hh \

src/hb-aat-layout-bsln-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_LAYOUT_BSLN_TABLE_HH
+#define HB_AAT_LAYOUT_BSLN_TABLE_HH
+
+#include "hb-aat-layout-common-private.hh"
+
+#define HB_AAT_TAG_bsln HB_TAG('b','s','l','n')
+
+
+namespace AAT {
+
+struct BaselineTableFormat0Part
+{
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this));
+  }
+
+  protected:
+  // Roman, Ideographic centered, Ideographic low, Hanging and Math
+  // are the default defined ones, but any other maybe accessed also.
+  HBINT16	deltas[32];	/* These are the FUnit distance deltas from
+				 * the font's natural baseline to the other
+				 * baselines used in the font. */
+  public:
+  DEFINE_SIZE_STATIC (64);
+};
+
+struct BaselineTableFormat1Part
+{
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && lookupTable.sanitize (c));
+  }
+
+  protected:
+  HBINT16	deltas[32];	/* ditto */
+  Lookup<HBUINT16>
+		lookupTable;	/* Lookup table that maps glyphs to their
+				 * baseline values. */
+  public:
+  DEFINE_SIZE_MIN (66);
+};
+
+struct BaselineTableFormat2Part
+{
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this));
+  }
+
+  protected:
+  GlyphID	stdGlyph;	/* The specific glyph index number in this
+				 * font that is used to set the baseline values.
+				 * This is the standard glyph.
+				 * This glyph must contain a set of control points
+				 * (whose numbers are contained in the ctlPoints field)
+				 * that are used to determine baseline distances. */
+  HBUINT16	ctlPoints[32];	/* Set of control point numbers,
+				 * associated with the standard glyph.
+				 * A value of 0xFFFF means there is no corresponding
+				 * control point in the standard glyph. */
+  public:
+  DEFINE_SIZE_STATIC (66);
+};
+
+struct BaselineTableFormat3Part
+{
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && lookupTable.sanitize (c));
+  }
+
+  protected:
+  GlyphID	stdGlyph;	/* ditto */
+  HBUINT16	ctlPoints[32];	/* ditto */
+  Lookup<HBUINT16>
+		lookupTable;	/* Lookup table that maps glyphs to their
+				 * baseline values. */
+  public:
+  DEFINE_SIZE_MIN (68);
+};
+
+/*
+ * bsln -- Baseline table
+ * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6bsln.html
+ */
+
+struct bsln
+{
+  static const hb_tag_t tableTag = HB_AAT_TAG_bsln;
+
+  inline bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    if (!(c->check_struct (this) && defaultBaseline < 32))
+      return_trace (false);
+
+    switch (format) {
+    case 0: return_trace (parts.format0.sanitize (c));
+    case 1: return_trace (parts.format1.sanitize (c));
+    case 2: return_trace (parts.format2.sanitize (c));
+    case 3: return_trace (parts.format3.sanitize (c));
+    default:return_trace (true);
+    }
+  }
+
+  protected:
+  FixedVersion<>version;	/* Version number of the Baseline table. */
+  HBUINT16	format;		/* Format of the baseline table. Only one baseline
+				 * format may be selected for the font. */
+  HBUINT16	defaultBaseline;/* Default baseline value for all glyphs.
+				 * This value can be from 0 through 31. */
+  union {
+  // Distance-Based Formats
+  BaselineTableFormat0Part	format0;
+  BaselineTableFormat1Part	format1;
+  // Control Point-based Formats
+  BaselineTableFormat2Part	format2;
+  BaselineTableFormat3Part	format3;
+  } parts;
+  public:
+  DEFINE_SIZE_MIN (8);
+};
+
+} /* namespace AAT */
+
+
+#endif /* HB_AAT_LAYOUT_BSLN_TABLE_HH */

src/hb-aat-layout.cc

@@ -31,10 +31,11 @@
 
 #include "hb-aat-layout-private.hh"
 #include "hb-aat-layout-ankr-table.hh"
+#include "hb-aat-layout-bsln-table.hh" // Just so we compile it; unused otherwise.
 #include "hb-aat-layout-kerx-table.hh"
 #include "hb-aat-layout-morx-table.hh"
 #include "hb-aat-layout-trak-table.hh"
-#include "hb-aat-fmtx-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-ltag-table.hh" // Just so we compile it; unused otherwise.
 
 /*