/*

 * Copyright © 2007,2008,2009,2010  Red Hat, Inc.

 * Copyright © 2010,2012  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.

 *

 * Red Hat Author(s): Behdad Esfahbod

 * Google Author(s): Behdad Esfahbod

 */

#ifndef HB_OT_LAYOUT_GSUBGPOS_PRIVATE_HH

#define HB_OT_LAYOUT_GSUBGPOS_PRIVATE_HH

#include "hb-private.hh"

#include "hb-debug.hh"

#include "hb-buffer-private.hh"

#include "hb-ot-layout-gdef-table.hh"

#include "hb-set-private.hh"

namespace OT {

struct hb_closure_context_t :

       hb_dispatch_context_t<hb_closure_context_t, hb_void_t, HB_DEBUG_CLOSURE>

{

  inline const char *get_name (void) { return "CLOSURE"; }

  typedef return_t (*recurse_func_t) (hb_closure_context_t *c, unsigned int lookup_index);

  template <typename T>

  inline return_t dispatch (const T &obj) { obj.closure (this); return HB_VOID; }

  static return_t default_return_value (void) { return HB_VOID; }

  bool stop_sublookup_iteration (return_t r HB_UNUSED) const { return false; }

  return_t recurse (unsigned int lookup_index)

  {

    if (unlikely (nesting_level_left == 0 || !recurse_func))

      return default_return_value ();

    nesting_level_left--;

    recurse_func (this, lookup_index);

    nesting_level_left++;

    return HB_VOID;

  }

  hb_face_t *face;

  hb_set_t *glyphs;

  recurse_func_t recurse_func;

  unsigned int nesting_level_left;

  unsigned int debug_depth;

  hb_closure_context_t (hb_face_t *face_,

                        hb_set_t *glyphs_,

                        unsigned int nesting_level_left_ = HB_MAX_NESTING_LEVEL) :

                          face (face_),

                          glyphs (glyphs_),

                          recurse_func (nullptr),

                          nesting_level_left (nesting_level_left_),

  void set_recurse_func (recurse_func_t func) { recurse_func = func; }

};

struct hb_would_apply_context_t :

       hb_dispatch_context_t<hb_would_apply_context_t, bool, HB_DEBUG_WOULD_APPLY>

{

  inline const char *get_name (void) { return "WOULD_APPLY"; }

  template <typename T>

  inline return_t dispatch (const T &obj) { return obj.would_apply (this); }

  static return_t default_return_value (void) { return false; }

  bool stop_sublookup_iteration (return_t r) const { return r; }

  hb_face_t *face;

  const hb_codepoint_t *glyphs;

  unsigned int len;

  bool zero_context;

  unsigned int debug_depth;

  hb_would_apply_context_t (hb_face_t *face_,

                            const hb_codepoint_t *glyphs_,

                            unsigned int len_,

                            bool zero_context_) :

                              face (face_),

                              glyphs (glyphs_),

                              len (len_),

                              zero_context (zero_context_),

                              debug_depth (0) {}

};

struct hb_collect_glyphs_context_t :

       hb_dispatch_context_t<hb_collect_glyphs_context_t, hb_void_t, HB_DEBUG_COLLECT_GLYPHS>

{

  inline const char *get_name (void) { return "COLLECT_GLYPHS"; }

  typedef return_t (*recurse_func_t) (hb_collect_glyphs_context_t *c, unsigned int lookup_index);

  template <typename T>

  inline return_t dispatch (const T &obj) { obj.collect_glyphs (this); return HB_VOID; }

  static return_t default_return_value (void) { return HB_VOID; }

  bool stop_sublookup_iteration (return_t r HB_UNUSED) const { return false; }

  return_t recurse (unsigned int lookup_index)

  {

    if (unlikely (nesting_level_left == 0 || !recurse_func))

      return default_return_value ();

    /* Note that GPOS sets recurse_func to nullptr already, so it doesn't get

     * past the previous check.  For GSUB, we only want to collect the output

     * glyphs in the recursion.  If output is not requested, we can go home now.

     *

     * Note further, that the above is not exactly correct.  A recursed lookup

     * is allowed to match input that is not matched in the context, but that's

     * not how most fonts are built.  It's possible to relax that and recurse

     * with all sets here if it proves to be an issue.

     */

    if (output == hb_set_get_empty ())

      return HB_VOID;

    /* Return if new lookup was recursed to before. */

    if (recursed_lookups->has (lookup_index))

      return HB_VOID;

    hb_set_t *old_before = before;

    hb_set_t *old_input  = input;

    hb_set_t *old_after  = after;

    before = input = after = hb_set_get_empty ();

    nesting_level_left--;

    recurse_func (this, lookup_index);

    nesting_level_left++;

    before = old_before;

    input  = old_input;

    after  = old_after;

    recursed_lookups->add (lookup_index);

    return HB_VOID;

  }

  hb_face_t *face;

  hb_set_t *before;

  hb_set_t *input;

  hb_set_t *after;

  hb_set_t *output;

  recurse_func_t recurse_func;

  hb_set_t *recursed_lookups;

  unsigned int nesting_level_left;

  unsigned int debug_depth;

  hb_collect_glyphs_context_t (hb_face_t *face_,

                               hb_set_t  *glyphs_before, /* OUT. May be nullptr */

                               hb_set_t  *glyphs_input,  /* OUT. May be nullptr */

                               hb_set_t  *glyphs_after,  /* OUT. May be nullptr */

                               hb_set_t  *glyphs_output, /* OUT. May be nullptr */

                               unsigned int nesting_level_left_ = HB_MAX_NESTING_LEVEL) :

                              face (face_),

                              before (glyphs_before ? glyphs_before : hb_set_get_empty ()),

                              input  (glyphs_input  ? glyphs_input  : hb_set_get_empty ()),

                              after  (glyphs_after  ? glyphs_after  : hb_set_get_empty ()),

                              output (glyphs_output ? glyphs_output : hb_set_get_empty ()),

                              recurse_func (nullptr),

                              recursed_lookups (nullptr),

                              nesting_level_left (nesting_level_left_),

                              debug_depth (0)

  {

    recursed_lookups = hb_set_create ();

  }

  ~hb_collect_glyphs_context_t (void)

  {

    hb_set_destroy (recursed_lookups);

  }

  void set_recurse_func (recurse_func_t func) { recurse_func = func; }

};

/* XXX Can we remove this? */

template <typename set_t>

struct hb_add_coverage_context_t :

       hb_dispatch_context_t<hb_add_coverage_context_t<set_t>, const Coverage &, HB_DEBUG_GET_COVERAGE>

{

  inline const char *get_name (void) { return "GET_COVERAGE"; }

  typedef const Coverage &return_t;

  template <typename T>

  inline return_t dispatch (const T &obj) { return obj.get_coverage (); }

  static return_t default_return_value (void) { return Null(Coverage); }

  bool stop_sublookup_iteration (return_t r) const

  {

    r.add_coverage (set);

    return false;

  }

  hb_add_coverage_context_t (set_t *set_) :

                            set (set_),

                            debug_depth (0) {}

  set_t *set;

  unsigned int debug_depth;

};

struct hb_ot_apply_context_t :

       hb_dispatch_context_t<hb_ot_apply_context_t, bool, HB_DEBUG_APPLY>

{

  struct matcher_t

  {

    inline matcher_t (void) :

             lookup_props (0),

             ignore_zwnj (false),

             ignore_zwj (false),

             mask (-1),

#define arg1(arg) (arg) /* Remove the macro to see why it's needed! */

             syllable arg1(0),

#undef arg1

             match_func (nullptr),

             match_data (nullptr) {};

    typedef bool (*match_func_t) (hb_codepoint_t glyph_id, const HBUINT16 &value, const void *data);

    inline void set_ignore_zwnj (bool ignore_zwnj_) { ignore_zwnj = ignore_zwnj_; }

    inline void set_ignore_zwj (bool ignore_zwj_) { ignore_zwj = ignore_zwj_; }

    inline void set_lookup_props (unsigned int lookup_props_) { lookup_props = lookup_props_; }

    inline void set_mask (hb_mask_t mask_) { mask = mask_; }

    inline void set_syllable (uint8_t syllable_)  { syllable = syllable_; }

    inline void set_match_func (match_func_t match_func_,

                                const void *match_data_)

    { match_func = match_func_; match_data = match_data_; }

    enum may_match_t {

      MATCH_NO,

      MATCH_YES,

      MATCH_MAYBE

    };

    inline may_match_t may_match (const hb_glyph_info_t &info,

                                  const HBUINT16          *glyph_data) const

    {

      if (!(info.mask & mask) ||

          (syllable && syllable != info.syllable ()))

        return MATCH_NO;

      if (match_func)

        return match_func (info.codepoint, *glyph_data, match_data) ? MATCH_YES : MATCH_NO;

      return MATCH_MAYBE;

    }

    enum may_skip_t {

      SKIP_NO,

      SKIP_YES,

      SKIP_MAYBE

    };

    inline may_skip_t

    may_skip (const hb_ot_apply_context_t *c,

              const hb_glyph_info_t    &info) const

    {

      if (!c->check_glyph_property (&info, lookup_props))

        return SKIP_YES;

      if (unlikely (_hb_glyph_info_is_default_ignorable_and_not_hidden (&info) &&

                    (ignore_zwnj || !_hb_glyph_info_is_zwnj (&info)) &&

                    (ignore_zwj || !_hb_glyph_info_is_zwj (&info))))

        return SKIP_MAYBE;

      return SKIP_NO;

    }

    protected:

    unsigned int lookup_props;

    bool ignore_zwnj;

    bool ignore_zwj;

    hb_mask_t mask;

    uint8_t syllable;

    match_func_t match_func;

    const void *match_data;

  };

  struct skipping_iterator_t

  {

    inline void init (hb_ot_apply_context_t *c_, bool context_match = false)

    {

      c = c_;

      match_glyph_data = nullptr;

      matcher.set_match_func (nullptr, nullptr);

      matcher.set_lookup_props (c->lookup_props);

      /* Ignore ZWNJ if we are matching GSUB context, or matching GPOS. */

      matcher.set_ignore_zwnj (c->table_index == 1 || (context_match && c->auto_zwnj));

      /* Ignore ZWJ if we are matching GSUB context, or matching GPOS, or if asked to. */

      matcher.set_ignore_zwj  (c->table_index == 1 || (context_match || c->auto_zwj));

      matcher.set_mask (context_match ? -1 : c->lookup_mask);

    }

    inline void set_lookup_props (unsigned int lookup_props)

    {

      matcher.set_lookup_props (lookup_props);

    }

    inline void set_match_func (matcher_t::match_func_t match_func_,

                                const void *match_data_,

                                const HBUINT16 glyph_data[])

    {

      matcher.set_match_func (match_func_, match_data_);

      match_glyph_data = glyph_data;

    }

    inline void reset (unsigned int start_index_,

                       unsigned int num_items_)

    {

      idx = start_index_;

      num_items = num_items_;

      end = c->buffer->len;

      matcher.set_syllable (start_index_ == c->buffer->idx ? c->buffer->cur().syllable () : 0);

    }

    inline void reject (void) { num_items++; match_glyph_data--; }

    inline matcher_t::may_skip_t

    may_skip (const hb_glyph_info_t    &info) const

    {

      return matcher.may_skip (c, info);

    }

    inline bool next (void)

    {

      assert (num_items > 0);

      while (idx + num_items < end)

      {

        idx++;

        const hb_glyph_info_t &info = c->buffer->info[idx];

        matcher_t::may_skip_t skip = matcher.may_skip (c, info);

        if (unlikely (skip == matcher_t::SKIP_YES))

          continue;

        matcher_t::may_match_t match = matcher.may_match (info, match_glyph_data);

        if (match == matcher_t::MATCH_YES ||

            (match == matcher_t::MATCH_MAYBE &&

             skip == matcher_t::SKIP_NO))

        {

          num_items--;

          match_glyph_data++;

          return true;

        }

        if (skip == matcher_t::SKIP_NO)

          return false;

      }

      return false;

    }

    inline bool prev (void)

    {

      assert (num_items > 0);

      while (idx >= num_items)

      {

        idx--;

        const hb_glyph_info_t &info = c->buffer->out_info[idx];

        matcher_t::may_skip_t skip = matcher.may_skip (c, info);

        if (unlikely (skip == matcher_t::SKIP_YES))

          continue;

        matcher_t::may_match_t match = matcher.may_match (info, match_glyph_data);

        if (match == matcher_t::MATCH_YES ||

            (match == matcher_t::MATCH_MAYBE &&

             skip == matcher_t::SKIP_NO))

        {

          num_items--;

          match_glyph_data++;

          return true;

        }

        if (skip == matcher_t::SKIP_NO)

          return false;

      }

      return false;

    }

    unsigned int idx;

    protected:

    hb_ot_apply_context_t *c;

    matcher_t matcher;

    const HBUINT16 *match_glyph_data;

    unsigned int num_items;

    unsigned int end;

  };

  inline const char *get_name (void) { return "APPLY"; }

  typedef return_t (*recurse_func_t) (hb_ot_apply_context_t *c, unsigned int lookup_index);

  template <typename T>

  inline return_t dispatch (const T &obj) { return obj.apply (this); }

  static return_t default_return_value (void) { return false; }

  bool stop_sublookup_iteration (return_t r) const { return r; }

  return_t recurse (unsigned int sub_lookup_index)

  {

    if (unlikely (nesting_level_left == 0 || !recurse_func || buffer->max_ops-- <= 0))

      return default_return_value ();

    nesting_level_left--;

    bool ret = recurse_func (this, sub_lookup_index);

    nesting_level_left++;

    return ret;

  }

  skipping_iterator_t iter_input, iter_context;

  hb_font_t *font;

  hb_face_t *face;

  hb_buffer_t *buffer;

  recurse_func_t recurse_func;

  const GDEF &gdef;

  const VariationStore &var_store;

  hb_direction_t direction;

  hb_mask_t lookup_mask;

  unsigned int table_index; /* GSUB/GPOS */

  unsigned int lookup_index;

  unsigned int lookup_props;

  unsigned int nesting_level_left;

  unsigned int debug_depth;

  bool auto_zwnj;

  bool auto_zwj;

  bool has_glyph_classes;

  hb_ot_apply_context_t (unsigned int table_index_,

                      hb_font_t *font_,

                      hb_buffer_t *buffer_) :

                        iter_input (), iter_context (),

                        font (font_), face (font->face), buffer (buffer_),

                        recurse_func (nullptr),

                        gdef (*hb_ot_layout_from_face (face)->gdef),

                        var_store (gdef.get_var_store ()),

                        direction (buffer_->props.direction),

                        lookup_mask (1),

                        table_index (table_index_),

                        lookup_index ((unsigned int) -1),

                        lookup_props (0),

                        nesting_level_left (HB_MAX_NESTING_LEVEL),

                        debug_depth (0),

                        auto_zwnj (true),

                        auto_zwj (true),

                        has_glyph_classes (gdef.has_glyph_classes ()) {}

  inline void set_lookup_mask (hb_mask_t mask) { lookup_mask = mask; }

  inline void set_auto_zwj (bool auto_zwj_) { auto_zwj = auto_zwj_; }

  inline void set_auto_zwnj (bool auto_zwnj_) { auto_zwnj = auto_zwnj_; }

  inline void set_recurse_func (recurse_func_t func) { recurse_func = func; }

  inline void set_lookup_index (unsigned int lookup_index_) { lookup_index = lookup_index_; }

  inline void set_lookup_props (unsigned int lookup_props_)

  {

    lookup_props = lookup_props_;

    iter_input.init (this, false);

    iter_context.init (this, true);

  }

  inline bool

  match_properties_mark (hb_codepoint_t  glyph,

                         unsigned int    glyph_props,

                         unsigned int    match_props) const

  {

    /* If using mark filtering sets, the high short of

     * match_props has the set index.

     */

    if (match_props & LookupFlag::UseMarkFilteringSet)

      return gdef.mark_set_covers (match_props >> 16, glyph);

    /* The second byte of match_props has the meaning

     * "ignore marks of attachment type different than

     * the attachment type specified."

     */

    if (match_props & LookupFlag::MarkAttachmentType)

      return (match_props & LookupFlag::MarkAttachmentType) == (glyph_props & LookupFlag::MarkAttachmentType);

    return true;

  }