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+/*
+ * Copyright © 2018 Ebrahim Byagowi
+ * Copyright © 2018 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_AAT_LAYOUT_KERX_TABLE_HH
+#define HB_AAT_LAYOUT_KERX_TABLE_HH
+
+#include "hb-kern.hh"
+#include "hb-aat-layout-ankr-table.hh"
+
+/*
+ * kerx -- Extended Kerning
+ * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6kerx.html
+ */
+#define HB_AAT_TAG_kerx HB_TAG('k','e','r','x')
+
+
+namespace AAT {
+
+using namespace OT;
+
+
+static inline int
+kerxTupleKern (int value,
+ unsigned int tupleCount,
+ const void *base,
+ hb_aat_apply_context_t *c)
+{
+ if (likely (!tupleCount || !c)) return value;
+
+ unsigned int offset = value;
+ const FWORD *pv = &StructAtOffset<FWORD> (base, offset);
+ if (unlikely (!c->sanitizer.check_array (pv, tupleCount))) return 0;
+ hb_barrier ();
+ return *pv;
+}
+
+
+struct hb_glyph_pair_t
+{
+ hb_codepoint_t left;
+ hb_codepoint_t right;
+};
+
+struct KernPair
+{
+ int get_kerning () const { return value; }
+
+ int cmp (const hb_glyph_pair_t &o) const
+ {
+ int ret = left.cmp (o.left);
+ if (ret) return ret;
+ return right.cmp (o.right);
+ }
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ return_trace (c->check_struct (this));
+ }
+
+ protected:
+ HBGlyphID16 left;
+ HBGlyphID16 right;
+ FWORD value;
+ public:
+ DEFINE_SIZE_STATIC (6);
+};
+
+template <typename KernSubTableHeader>
+struct KerxSubTableFormat0
+{
+ int get_kerning (hb_codepoint_t left, hb_codepoint_t right,
+ hb_aat_apply_context_t *c = nullptr) const
+ {
+ hb_glyph_pair_t pair = {left, right};
+ int v = pairs.bsearch (pair).get_kerning ();
+ return kerxTupleKern (v, header.tuple_count (), this, c);
+ }
+
+ bool apply (hb_aat_apply_context_t *c) const
+ {
+ TRACE_APPLY (this);
+
+ if (!c->plan->requested_kerning)
+ return false;
+
+ if (header.coverage & header.Backwards)
+ return false;
+
+ accelerator_t accel (*this, c);
+ hb_kern_machine_t<accelerator_t> machine (accel, header.coverage & header.CrossStream);
+ machine.kern (c->font, c->buffer, c->plan->kern_mask);
+
+ return_trace (true);
+ }
+
+ struct accelerator_t
+ {
+ const KerxSubTableFormat0 &table;
+ hb_aat_apply_context_t *c;
+
+ accelerator_t (const KerxSubTableFormat0 &table_,
+ hb_aat_apply_context_t *c_) :
+ table (table_), c (c_) {}
+
+ int get_kerning (hb_codepoint_t left, hb_codepoint_t right) const
+ { return table.get_kerning (left, right, c); }
+ };
+
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ return_trace (likely (pairs.sanitize (c)));
+ }
+
+ protected:
+ KernSubTableHeader header;
+ BinSearchArrayOf<KernPair, typename KernSubTableHeader::Types::HBUINT>
+ pairs; /* Sorted kern records. */
+ public:
+ DEFINE_SIZE_ARRAY (KernSubTableHeader::static_size + 16, pairs);
+};
+
+
+template <bool extended>
+struct Format1Entry;
+
+template <>
+struct Format1Entry<true>
+{
+ enum Flags
+ {
+ Push = 0x8000, /* If set, push this glyph on the kerning stack. */
+ DontAdvance = 0x4000, /* If set, don't advance to the next glyph
+ * before going to the new state. */
+ Reset = 0x2000, /* If set, reset the kerning data (clear the stack) */
+ Reserved = 0x1FFF, /* Not used; set to 0. */
+ };
+
+ struct EntryData
+ {
+ HBUINT16 kernActionIndex;/* Index into the kerning value array. If
+ * this index is 0xFFFF, then no kerning
+ * is to be performed. */
+ public:
+ DEFINE_SIZE_STATIC (2);
+ };
+
+ static bool performAction (const Entry<EntryData> &entry)
+ { return entry.data.kernActionIndex != 0xFFFF; }
+
+ static unsigned int kernActionIndex (const Entry<EntryData> &entry)
+ { return entry.data.kernActionIndex; }
+};
+template <>
+struct Format1Entry<false>
+{
+ enum Flags
+ {
+ Push = 0x8000, /* If set, push this glyph on the kerning stack. */
+ DontAdvance = 0x4000, /* If set, don't advance to the next glyph
+ * before going to the new state. */
+ Offset = 0x3FFF, /* Byte offset from beginning of subtable to the
+ * value table for the glyphs on the kerning stack. */
+
+ Reset = 0x0000, /* Not supported? */
+ };
+
+ typedef void EntryData;
+
+ static bool performAction (const Entry<EntryData> &entry)
+ { return entry.flags & Offset; }
+
+ static unsigned int kernActionIndex (const Entry<EntryData> &entry)
+ { return entry.flags & Offset; }
+};
+
+template <typename KernSubTableHeader>
+struct KerxSubTableFormat1
+{
+ typedef typename KernSubTableHeader::Types Types;
+ typedef typename Types::HBUINT HBUINT;
+
+ typedef Format1Entry<Types::extended> Format1EntryT;
+ typedef typename Format1EntryT::EntryData EntryData;
+
+ struct driver_context_t
+ {
+ static constexpr bool in_place = true;
+ enum
+ {
+ DontAdvance = Format1EntryT::DontAdvance,
+ };
+
+ driver_context_t (const KerxSubTableFormat1 *table_,
+ hb_aat_apply_context_t *c_) :
+ c (c_),
+ table (table_),
+ /* Apparently the offset kernAction is from the beginning of the state-machine,
+ * similar to offsets in morx table, NOT from beginning of this table, like
+ * other subtables in kerx. Discovered via testing. */
+ kernAction (&table->machine + table->kernAction),
+ depth (0),
+ crossStream (table->header.coverage & table->header.CrossStream) {}
+
+ bool is_actionable (StateTableDriver<Types, EntryData> *driver HB_UNUSED,
+ const Entry<EntryData> &entry)
+ { return Format1EntryT::performAction (entry); }
+ void transition (StateTableDriver<Types, EntryData> *driver,
+ const Entry<EntryData> &entry)
+ {
+ hb_buffer_t *buffer = driver->buffer;
+ unsigned int flags = entry.flags;
+
+ if (flags & Format1EntryT::Reset)
+ depth = 0;
+
+ if (flags & Format1EntryT::Push)
+ {
+ if (likely (depth < ARRAY_LENGTH (stack)))
+ stack[depth++] = buffer->idx;
+ else
+ depth = 0; /* Probably not what CoreText does, but better? */
+ }
+
+ if (Format1EntryT::performAction (entry) && depth)
+ {
+ unsigned int tuple_count = hb_max (1u, table->header.tuple_count ());
+
+ unsigned int kern_idx = Format1EntryT::kernActionIndex (entry);
+ kern_idx = Types::byteOffsetToIndex (kern_idx, &table->machine, kernAction.arrayZ);
+ const FWORD *actions = &kernAction[kern_idx];
+ if (!c->sanitizer.check_array (actions, depth, tuple_count))
+ {
+ depth = 0;
+ return;
+ }
+ hb_barrier ();
+
+ hb_mask_t kern_mask = c->plan->kern_mask;
+
+ /* From Apple 'kern' spec:
+ * "Each pops one glyph from the kerning stack and applies the kerning value to it.
+ * The end of the list is marked by an odd value... */
+ bool last = false;
+ while (!last && depth)
+ {
+ unsigned int idx = stack[--depth];
+ int v = *actions;
+ actions += tuple_count;
+ if (idx >= buffer->len) continue;
+
+ /* "The end of the list is marked by an odd value..." */
+ last = v & 1;
+ v &= ~1;
+
+ hb_glyph_position_t &o = buffer->pos[idx];
+
+ if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
+ {
+ if (crossStream)
+ {
+ /* The following flag is undocumented in the spec, but described
+ * in the 'kern' table example. */
+ if (v == -0x8000)
+ {
+ o.attach_type() = OT::Layout::GPOS_impl::ATTACH_TYPE_NONE;
+ o.attach_chain() = 0;
+ o.y_offset = 0;
+ }
+ else if (o.attach_type())
+ {
+ o.y_offset += c->font->em_scale_y (v);
+ buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
+ }
+ }
+ else if (buffer->info[idx].mask & kern_mask)
+ {
+ o.x_advance += c->font->em_scale_x (v);
+ o.x_offset += c->font->em_scale_x (v);
+ }
+ }
+ else
+ {
+ if (crossStream)
+ {
+ /* CoreText doesn't do crossStream kerning in vertical. We do. */
+ if (v == -0x8000)
+ {
+ o.attach_type() = OT::Layout::GPOS_impl::ATTACH_TYPE_NONE;
+ o.attach_chain() = 0;
+ o.x_offset = 0;
+ }
+ else if (o.attach_type())
+ {
+ o.x_offset += c->font->em_scale_x (v);
+ buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
+ }
+ }
+ else if (buffer->info[idx].mask & kern_mask)
+ {
+ o.y_advance += c->font->em_scale_y (v);
+ o.y_offset += c->font->em_scale_y (v);
+ }
+ }
+ }
+ }
+ }
+
+ private:
+ hb_aat_apply_context_t *c;
+ const KerxSubTableFormat1 *table;
+ const UnsizedArrayOf<FWORD> &kernAction;
+ unsigned int stack[8];
+ unsigned int depth;
+ bool crossStream;
+ };
+
+ bool apply (hb_aat_apply_context_t *c) const
+ {
+ TRACE_APPLY (this);
+
+ if (!c->plan->requested_kerning &&
+ !(header.coverage & header.CrossStream))
+ return false;
+
+ driver_context_t dc (this, c);
+
+ StateTableDriver<Types, EntryData> driver (machine, c->buffer, c->font->face);
+ driver.drive (&dc, c);
+
+ return_trace (true);
+ }
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ /* The rest of array sanitizations are done at run-time. */
+ return_trace (likely (c->check_struct (this) &&
+ machine.sanitize (c)));
+ }
+
+ protected:
+ KernSubTableHeader header;
+ StateTable<Types, EntryData> machine;
+ NNOffsetTo<UnsizedArrayOf<FWORD>, HBUINT> kernAction;
+ public:
+ DEFINE_SIZE_STATIC (KernSubTableHeader::static_size + 5 * sizeof (HBUINT));
+};
+
+template <typename KernSubTableHeader>
+struct KerxSubTableFormat2
+{
+ typedef typename KernSubTableHeader::Types Types;
+ typedef typename Types::HBUINT HBUINT;
+
+ int get_kerning (hb_codepoint_t left, hb_codepoint_t right,
+ hb_aat_apply_context_t *c) const
+ {
+ unsigned int num_glyphs = c->sanitizer.get_num_glyphs ();
+ unsigned int l = (this+leftClassTable).get_class (left, num_glyphs, 0);
+ unsigned int r = (this+rightClassTable).get_class (right, num_glyphs, 0);
+
+ const UnsizedArrayOf<FWORD> &arrayZ = this+array;
+ unsigned int kern_idx = l + r;
+ kern_idx = Types::offsetToIndex (kern_idx, this, arrayZ.arrayZ);
+ const FWORD *v = &arrayZ[kern_idx];
+ if (unlikely (!v->sanitize (&c->sanitizer))) return 0;
+ hb_barrier ();
+
+ return kerxTupleKern (*v, header.tuple_count (), this, c);
+ }
+
+ bool apply (hb_aat_apply_context_t *c) const
+ {
+ TRACE_APPLY (this);
+
+ if (!c->plan->requested_kerning)
+ return false;
+
+ if (header.coverage & header.Backwards)
+ return false;
+
+ accelerator_t accel (*this, c);
+ hb_kern_machine_t<accelerator_t> machine (accel, header.coverage & header.CrossStream);
+ machine.kern (c->font, c->buffer, c->plan->kern_mask);
+
+ return_trace (true);
+ }
+
+ struct accelerator_t
+ {
+ const KerxSubTableFormat2 &table;
+ hb_aat_apply_context_t *c;
+
+ accelerator_t (const KerxSubTableFormat2 &table_,
+ hb_aat_apply_context_t *c_) :
+ table (table_), c (c_) {}
+
+ int get_kerning (hb_codepoint_t left, hb_codepoint_t right) const
+ { return table.get_kerning (left, right, c); }
+ };
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ return_trace (likely (c->check_struct (this) &&
+ leftClassTable.sanitize (c, this) &&
+ rightClassTable.sanitize (c, this) &&
+ hb_barrier () &&
+ c->check_range (this, array)));
+ }
+
+ protected:
+ KernSubTableHeader header;
+ HBUINT rowWidth; /* The width, in bytes, of a row in the table. */
+ NNOffsetTo<typename Types::ClassTypeWide, HBUINT>
+ leftClassTable; /* Offset from beginning of this subtable to
+ * left-hand class table. */
+ NNOffsetTo<typename Types::ClassTypeWide, HBUINT>
+ rightClassTable;/* Offset from beginning of this subtable to
+ * right-hand class table. */
+ NNOffsetTo<UnsizedArrayOf<FWORD>, HBUINT>
+ array; /* Offset from beginning of this subtable to
+ * the start of the kerning array. */
+ public:
+ DEFINE_SIZE_STATIC (KernSubTableHeader::static_size + 4 * sizeof (HBUINT));
+};
+
+template <typename KernSubTableHeader>
+struct KerxSubTableFormat4
+{
+ typedef ExtendedTypes Types;
+
+ struct EntryData
+ {
+ HBUINT16 ankrActionIndex;/* Either 0xFFFF (for no action) or the index of
+ * the action to perform. */
+ public:
+ DEFINE_SIZE_STATIC (2);
+ };
+
+ struct driver_context_t
+ {
+ static constexpr bool in_place = true;
+ enum Flags
+ {
+ Mark = 0x8000, /* If set, remember this glyph as the marked glyph. */
+ DontAdvance = 0x4000, /* If set, don't advance to the next glyph before
+ * going to the new state. */
+ Reserved = 0x3FFF, /* Not used; set to 0. */
+ };
+
+ enum SubTableFlags
+ {
+ ActionType = 0xC0000000, /* A two-bit field containing the action type. */
+ Unused = 0x3F000000, /* Unused - must be zero. */
+ Offset = 0x00FFFFFF, /* Masks the offset in bytes from the beginning
+ * of the subtable to the beginning of the control
+ * point table. */
+ };
+
+ driver_context_t (const KerxSubTableFormat4 *table,
+ hb_aat_apply_context_t *c_) :
+ c (c_),
+ action_type ((table->flags & ActionType) >> 30),
+ ankrData ((HBUINT16 *) ((const char *) &table->machine + (table->flags & Offset))),
+ mark_set (false),
+ mark (0) {}
+
+ bool is_actionable (StateTableDriver<Types, EntryData> *driver HB_UNUSED,
+ const Entry<EntryData> &entry)
+ { return entry.data.ankrActionIndex != 0xFFFF; }
+ void transition (StateTableDriver<Types, EntryData> *driver,
+ const Entry<EntryData> &entry)
+ {
+ hb_buffer_t *buffer = driver->buffer;
+
+ if (mark_set && entry.data.ankrActionIndex != 0xFFFF && buffer->idx < buffer->len)
+ {
+ hb_glyph_position_t &o = buffer->cur_pos();
+ switch (action_type)
+ {
+ case 0: /* Control Point Actions.*/
+ {
+ /* Indexed into glyph outline. */
+ /* Each action (record in ankrData) contains two 16-bit fields, so we must
+ double the ankrActionIndex to get the correct offset here. */
+ const HBUINT16 *data = &ankrData[entry.data.ankrActionIndex * 2];
+ if (!c->sanitizer.check_array (data, 2)) return;
+ hb_barrier ();
+ unsigned int markControlPoint = *data++;
+ unsigned int currControlPoint = *data++;
+ hb_position_t markX = 0;
+ hb_position_t markY = 0;
+ hb_position_t currX = 0;
+ hb_position_t currY = 0;
+ if (!c->font->get_glyph_contour_point_for_origin (c->buffer->info[mark].codepoint,
+ markControlPoint,
+ HB_DIRECTION_LTR /*XXX*/,
+ &markX, &markY) ||
+ !c->font->get_glyph_contour_point_for_origin (c->buffer->cur ().codepoint,
+ currControlPoint,
+ HB_DIRECTION_LTR /*XXX*/,
+ &currX, &currY))
+ return;
+
+ o.x_offset = markX - currX;
+ o.y_offset = markY - currY;
+ }
+ break;
+
+ case 1: /* Anchor Point Actions. */
+ {
+ /* Indexed into 'ankr' table. */
+ /* Each action (record in ankrData) contains two 16-bit fields, so we must
+ double the ankrActionIndex to get the correct offset here. */
+ const HBUINT16 *data = &ankrData[entry.data.ankrActionIndex * 2];
+ if (!c->sanitizer.check_array (data, 2)) return;
+ hb_barrier ();
+ unsigned int markAnchorPoint = *data++;
+ unsigned int currAnchorPoint = *data++;
+ const Anchor &markAnchor = c->ankr_table->get_anchor (c->buffer->info[mark].codepoint,
+ markAnchorPoint,
+ c->sanitizer.get_num_glyphs ());
+ const Anchor &currAnchor = c->ankr_table->get_anchor (c->buffer->cur ().codepoint,
+ currAnchorPoint,
+ c->sanitizer.get_num_glyphs ());
+
+ o.x_offset = c->font->em_scale_x (markAnchor.xCoordinate) - c->font->em_scale_x (currAnchor.xCoordinate);
+ o.y_offset = c->font->em_scale_y (markAnchor.yCoordinate) - c->font->em_scale_y (currAnchor.yCoordinate);
+ }
+ break;
+
+ case 2: /* Control Point Coordinate Actions. */
+ {
+ /* Each action contains four 16-bit fields, so we multiply the ankrActionIndex
+ by 4 to get the correct offset for the given action. */
+ const FWORD *data = (const FWORD *) &ankrData[entry.data.ankrActionIndex * 4];
+ if (!c->sanitizer.check_array (data, 4)) return;
+ hb_barrier ();
+ int markX = *data++;
+ int markY = *data++;
+ int currX = *data++;
+ int currY = *data++;
+
+ o.x_offset = c->font->em_scale_x (markX) - c->font->em_scale_x (currX);
+ o.y_offset = c->font->em_scale_y (markY) - c->font->em_scale_y (currY);
+ }
+ break;
+ }
+ o.attach_type() = OT::Layout::GPOS_impl::ATTACH_TYPE_MARK;
+ o.attach_chain() = (int) mark - (int) buffer->idx;
+ buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
+ }
+
+ if (entry.flags & Mark)
+ {
+ mark_set = true;
+ mark = buffer->idx;
+ }
+ }
+
+ private:
+ hb_aat_apply_context_t *c;
+ unsigned int action_type;
+ const HBUINT16 *ankrData;
+ bool mark_set;
+ unsigned int mark;
+ };
+
+ bool apply (hb_aat_apply_context_t *c) const
+ {
+ TRACE_APPLY (this);
+
+ driver_context_t dc (this, c);
+
+ StateTableDriver<Types, EntryData> driver (machine, c->buffer, c->font->face);
+ driver.drive (&dc, c);
+
+ return_trace (true);
+ }
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ /* The rest of array sanitizations are done at run-time. */
+ return_trace (likely (c->check_struct (this) &&
+ machine.sanitize (c)));
+ }
+
+ protected:
+ KernSubTableHeader header;
+ StateTable<Types, EntryData> machine;
+ HBUINT32 flags;
+ public:
+ DEFINE_SIZE_STATIC (KernSubTableHeader::static_size + 20);
+};
+
+template <typename KernSubTableHeader>
+struct KerxSubTableFormat6
+{
+ enum Flags
+ {
+ ValuesAreLong = 0x00000001,
+ };
+
+ bool is_long () const { return flags & ValuesAreLong; }
+
+ int get_kerning (hb_codepoint_t left, hb_codepoint_t right,
+ hb_aat_apply_context_t *c) const
+ {
+ unsigned int num_glyphs = c->sanitizer.get_num_glyphs ();
+ if (is_long ())
+ {
+ const typename U::Long &t = u.l;
+ unsigned int l = (this+t.rowIndexTable).get_value_or_null (left, num_glyphs);
+ unsigned int r = (this+t.columnIndexTable).get_value_or_null (right, num_glyphs);
+ unsigned int offset = l + r;
+ if (unlikely (offset < l)) return 0; /* Addition overflow. */
+ if (unlikely (hb_unsigned_mul_overflows (offset, sizeof (FWORD32)))) return 0;
+ const FWORD32 *v = &StructAtOffset<FWORD32> (&(this+t.array), offset * sizeof (FWORD32));
+ if (unlikely (!v->sanitize (&c->sanitizer))) return 0;
+ hb_barrier ();
+ return kerxTupleKern (*v, header.tuple_count (), &(this+vector), c);
+ }
+ else
+ {
+ const typename U::Short &t = u.s;
+ unsigned int l = (this+t.rowIndexTable).get_value_or_null (left, num_glyphs);
+ unsigned int r = (this+t.columnIndexTable).get_value_or_null (right, num_glyphs);
+ unsigned int offset = l + r;
+ const FWORD *v = &StructAtOffset<FWORD> (&(this+t.array), offset * sizeof (FWORD));
+ if (unlikely (!v->sanitize (&c->sanitizer))) return 0;
+ hb_barrier ();
+ return kerxTupleKern (*v, header.tuple_count (), &(this+vector), c);
+ }
+ }
+
+ bool apply (hb_aat_apply_context_t *c) const
+ {
+ TRACE_APPLY (this);
+
+ if (!c->plan->requested_kerning)
+ return false;
+
+ if (header.coverage & header.Backwards)
+ return false;
+
+ accelerator_t accel (*this, c);
+ hb_kern_machine_t<accelerator_t> machine (accel, header.coverage & header.CrossStream);
+ machine.kern (c->font, c->buffer, c->plan->kern_mask);
+
+ return_trace (true);
+ }
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ return_trace (likely (c->check_struct (this) &&
+ hb_barrier () &&
+ (is_long () ?
+ (
+ u.l.rowIndexTable.sanitize (c, this) &&
+ u.l.columnIndexTable.sanitize (c, this) &&
+ c->check_range (this, u.l.array)
+ ) : (
+ u.s.rowIndexTable.sanitize (c, this) &&
+ u.s.columnIndexTable.sanitize (c, this) &&
+ c->check_range (this, u.s.array)
+ )) &&
+ (header.tuple_count () == 0 ||
+ c->check_range (this, vector))));
+ }
+
+ struct accelerator_t
+ {
+ const KerxSubTableFormat6 &table;
+ hb_aat_apply_context_t *c;
+
+ accelerator_t (const KerxSubTableFormat6 &table_,
+ hb_aat_apply_context_t *c_) :
+ table (table_), c (c_) {}
+
+ int get_kerning (hb_codepoint_t left, hb_codepoint_t right) const
+ { return table.get_kerning (left, right, c); }
+ };
+
+ protected:
+ KernSubTableHeader header;
+ HBUINT32 flags;
+ HBUINT16 rowCount;
+ HBUINT16 columnCount;
+ union U
+ {
+ struct Long
+ {
+ NNOffset32To<Lookup<HBUINT32>> rowIndexTable;
+ NNOffset32To<Lookup<HBUINT32>> columnIndexTable;
+ NNOffset32To<UnsizedArrayOf<FWORD32>> array;
+ } l;
+ struct Short
+ {
+ NNOffset32To<Lookup<HBUINT16>> rowIndexTable;
+ NNOffset32To<Lookup<HBUINT16>> columnIndexTable;
+ NNOffset32To<UnsizedArrayOf<FWORD>> array;
+ } s;
+ } u;
+ NNOffset32To<UnsizedArrayOf<FWORD>> vector;
+ public:
+ DEFINE_SIZE_STATIC (KernSubTableHeader::static_size + 24);
+};
+
+
+struct KerxSubTableHeader
+{
+ typedef ExtendedTypes Types;
+
+ unsigned tuple_count () const { return tupleCount; }
+ bool is_horizontal () const { return !(coverage & Vertical); }
+
+ enum Coverage
+ {
+ Vertical = 0x80000000u, /* Set if table has vertical kerning values. */
+ CrossStream = 0x40000000u, /* Set if table has cross-stream kerning values. */
+ Variation = 0x20000000u, /* Set if table has variation kerning values. */
+ Backwards = 0x10000000u, /* If clear, process the glyphs forwards, that
+ * is, from first to last in the glyph stream.
+ * If we, process them from last to first.
+ * This flag only applies to state-table based
+ * 'kerx' subtables (types 1 and 4). */
+ Reserved = 0x0FFFFF00u, /* Reserved, set to zero. */
+ SubtableType= 0x000000FFu, /* Subtable type. */
+ };
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ return_trace (c->check_struct (this));
+ }
+
+ public:
+ HBUINT32 length;
+ HBUINT32 coverage;
+ HBUINT32 tupleCount;
+ public:
+ DEFINE_SIZE_STATIC (12);
+};
+
+struct KerxSubTable
+{
+ friend struct kerx;
+
+ unsigned int get_size () const { return u.header.length; }
+ unsigned int get_type () const { return u.header.coverage & u.header.SubtableType; }
+
+ template <typename context_t, typename ...Ts>
+ typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
+ {
+ unsigned int subtable_type = get_type ();
+ TRACE_DISPATCH (this, subtable_type);
+ switch (subtable_type) {
+ case 0: return_trace (c->dispatch (u.format0, std::forward<Ts> (ds)...));
+ case 1: return_trace (c->dispatch (u.format1, std::forward<Ts> (ds)...));
+ case 2: return_trace (c->dispatch (u.format2, std::forward<Ts> (ds)...));
+ case 4: return_trace (c->dispatch (u.format4, std::forward<Ts> (ds)...));
+ case 6: return_trace (c->dispatch (u.format6, std::forward<Ts> (ds)...));
+ default: return_trace (c->default_return_value ());
+ }
+ }
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ if (!(u.header.sanitize (c) &&
+ hb_barrier () &&
+ u.header.length >= u.header.static_size &&
+ c->check_range (this, u.header.length)))
+ return_trace (false);
+
+ return_trace (dispatch (c));
+ }
+
+ public:
+ union {
+ KerxSubTableHeader header;
+ KerxSubTableFormat0<KerxSubTableHeader> format0;
+ KerxSubTableFormat1<KerxSubTableHeader> format1;
+ KerxSubTableFormat2<KerxSubTableHeader> format2;
+ KerxSubTableFormat4<KerxSubTableHeader> format4;
+ KerxSubTableFormat6<KerxSubTableHeader> format6;
+ } u;
+ public:
+ DEFINE_SIZE_MIN (12);
+};
+
+
+/*
+ * The 'kerx' Table
+ */
+
+template <typename T>
+struct KerxTable
+{
+ /* https://en.wikipedia.org/wiki/Curiously_recurring_template_pattern */
+ const T* thiz () const { return static_cast<const T *> (this); }
+
+ bool has_state_machine () const
+ {
+ typedef typename T::SubTable SubTable;
+
+ const SubTable *st = &thiz()->firstSubTable;
+ unsigned int count = thiz()->tableCount;
+ for (unsigned int i = 0; i < count; i++)
+ {
+ if (st->get_type () == 1)
+ return true;
+ st = &StructAfter<SubTable> (*st);
+ }
+ return false;
+ }
+
+ bool has_cross_stream () const
+ {
+ typedef typename T::SubTable SubTable;
+
+ const SubTable *st = &thiz()->firstSubTable;
+ unsigned int count = thiz()->tableCount;
+ for (unsigned int i = 0; i < count; i++)
+ {
+ if (st->u.header.coverage & st->u.header.CrossStream)
+ return true;
+ st = &StructAfter<SubTable> (*st);
+ }
+ return false;
+ }
+
+ int get_h_kerning (hb_codepoint_t left, hb_codepoint_t right) const
+ {
+ typedef typename T::SubTable SubTable;
+
+ int v = 0;
+ const SubTable *st = &thiz()->firstSubTable;
+ unsigned int count = thiz()->tableCount;
+ for (unsigned int i = 0; i < count; i++)
+ {
+ if ((st->u.header.coverage & (st->u.header.Variation | st->u.header.CrossStream)) ||
+ !st->u.header.is_horizontal ())
+ continue;
+ v += st->get_kerning (left, right);
+ st = &StructAfter<SubTable> (*st);
+ }
+ return v;
+ }
+
+ bool apply (AAT::hb_aat_apply_context_t *c) const
+ {
+ c->buffer->unsafe_to_concat ();
+
+ typedef typename T::SubTable SubTable;
+
+ bool ret = false;
+ bool seenCrossStream = false;
+ c->set_lookup_index (0);
+ const SubTable *st = &thiz()->firstSubTable;
+ unsigned int count = thiz()->tableCount;
+ for (unsigned int i = 0; i < count; i++)
+ {
+ bool reverse;
+
+ if (!T::Types::extended && (st->u.header.coverage & st->u.header.Variation))
+ goto skip;
+
+ if (HB_DIRECTION_IS_HORIZONTAL (c->buffer->props.direction) != st->u.header.is_horizontal ())
+ goto skip;
+
+ reverse = bool (st->u.header.coverage & st->u.header.Backwards) !=
+ HB_DIRECTION_IS_BACKWARD (c->buffer->props.direction);
+
+ if (!c->buffer->message (c->font, "start subtable %u", c->lookup_index))
+ goto skip;
+
+ if (!seenCrossStream &&
+ (st->u.header.coverage & st->u.header.CrossStream))
+ {
+ /* Attach all glyphs into a chain. */
+ seenCrossStream = true;
+ hb_glyph_position_t *pos = c->buffer->pos;
+ unsigned int count = c->buffer->len;
+ for (unsigned int i = 0; i < count; i++)
+ {
+ pos[i].attach_type() = OT::Layout::GPOS_impl::ATTACH_TYPE_CURSIVE;
+ pos[i].attach_chain() = HB_DIRECTION_IS_FORWARD (c->buffer->props.direction) ? -1 : +1;
+ /* We intentionally don't set HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT,
+ * since there needs to be a non-zero attachment for post-positioning to
+ * be needed. */
+ }
+ }
+
+ if (reverse)
+ c->buffer->reverse ();
+
+ {
+ /* See comment in sanitize() for conditional here. */
+ hb_sanitize_with_object_t with (&c->sanitizer, i < count - 1 ? st : (const SubTable *) nullptr);
+ ret |= st->dispatch (c);
+ }
+
+ if (reverse)
+ c->buffer->reverse ();
+
+ (void) c->buffer->message (c->font, "end subtable %u", c->lookup_index);
+
+ skip:
+ st = &StructAfter<SubTable> (*st);
+ c->set_lookup_index (c->lookup_index + 1);
+ }
+
+ return ret;
+ }
+
+ bool sanitize (hb_sanitize_context_t *c) const
+ {
+ TRACE_SANITIZE (this);
+ if (unlikely (!(thiz()->version.sanitize (c) &&
+ hb_barrier () &&
+ (unsigned) thiz()->version >= (unsigned) T::minVersion &&
+ thiz()->tableCount.sanitize (c))))
+ return_trace (false);
+
+ typedef typename T::SubTable SubTable;
+
+ const SubTable *st = &thiz()->firstSubTable;
+ unsigned int count = thiz()->tableCount;
+ for (unsigned int i = 0; i < count; i++)
+ {
+ if (unlikely (!st->u.header.sanitize (c)))
+ return_trace (false);
+ hb_barrier ();
+ /* OpenType kern table has 2-byte subtable lengths. That's limiting.
+ * MS implementation also only supports one subtable, of format 0,
+ * anyway. Certain versions of some fonts, like Calibry, contain
+ * kern subtable that exceeds 64kb. Looks like, the subtable length
+ * is simply ignored. Which makes sense. It's only needed if you
+ * have multiple subtables. To handle such fonts, we just ignore
+ * the length for the last subtable. */
+ hb_sanitize_with_object_t with (c, i < count - 1 ? st : (const SubTable *) nullptr);
+
+ if (unlikely (!st->sanitize (c)))
+ return_trace (false);
+
+ st = &StructAfter<SubTable> (*st);
+ }
+
+ return_trace (true);
+ }
+};
+
+struct kerx : KerxTable<kerx>
+{
+ friend struct KerxTable<kerx>;
+
+ static constexpr hb_tag_t tableTag = HB_AAT_TAG_kerx;
+ static constexpr unsigned minVersion = 2u;
+
+ typedef KerxSubTableHeader SubTableHeader;
+ typedef SubTableHeader::Types Types;
+ typedef KerxSubTable SubTable;
+
+ bool has_data () const { return version; }
+
+ protected:
+ HBUINT16 version; /* The version number of the extended kerning table
+ * (currently 2, 3, or 4). */
+ HBUINT16 unused; /* Set to 0. */
+ HBUINT32 tableCount; /* The number of subtables included in the extended kerning
+ * table. */
+ SubTable firstSubTable; /* Subtables. */
+/*subtableGlyphCoverageArray*/ /* Only if version >= 3. We don't use. */
+
+ public:
+ DEFINE_SIZE_MIN (8);
+};
+
+
+} /* namespace AAT */
+
+
+#endif /* HB_AAT_LAYOUT_KERX_TABLE_HH */