/*

 * Copyright © 2011,2014  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, Roozbeh Pournader

 */

#include "hb-private.hh"

#include "hb-ot.h"

#include "hb-font-private.hh"

#include "hb-ot-cmap-table.hh"

#include "hb-ot-cbdt-table.hh"

#include "hb-ot-glyf-table.hh"

#include "hb-ot-head-table.hh"

#include "hb-ot-hhea-table.hh"

#include "hb-ot-hmtx-table.hh"

#include "hb-ot-os2-table.hh"

//#include "hb-ot-post-table.hh"

struct hb_ot_face_metrics_accelerator_t

{

  unsigned int num_metrics;

  unsigned int num_advances;

  unsigned int default_advance;

  unsigned short ascender;

  unsigned short descender;

  unsigned short line_gap;

  bool has_font_extents;

  const OT::_mtx *table;

  hb_blob_t *blob;

  inline void init (hb_face_t *face,

                    hb_tag_t _hea_tag,

                    hb_tag_t _mtx_tag,

                    hb_tag_t os2_tag,

                    unsigned int default_advance = 0)

  {

    this->default_advance = default_advance ? default_advance : face->get_upem ();

    bool got_font_extents = false;

    if (os2_tag)

    {

      hb_blob_t *os2_blob = OT::Sanitizer<OT::os2>::sanitize (face->reference_table (os2_tag));

      const OT::os2 *os2 = OT::Sanitizer<OT::os2>::lock_instance (os2_blob);

#define USE_TYPO_METRICS (1u<<7)

      if (0 != (os2->fsSelection & USE_TYPO_METRICS))

      {

        this->ascender = os2->sTypoAscender;

        this->descender = os2->sTypoDescender;

        this->line_gap = os2->sTypoLineGap;

        got_font_extents = (this->ascender | this->descender) != 0;

      }

      hb_blob_destroy (os2_blob);

    }

    hb_blob_t *_hea_blob = OT::Sanitizer<OT::_hea>::sanitize (face->reference_table (_hea_tag));

    const OT::_hea *_hea = OT::Sanitizer<OT::_hea>::lock_instance (_hea_blob);

    this->num_advances = _hea->numberOfLongMetrics;

    if (!got_font_extents)

    {

      this->ascender = _hea->ascender;

      this->descender = _hea->descender;

      this->line_gap = _hea->lineGap;

      got_font_extents = (this->ascender | this->descender) != 0;

    }

    hb_blob_destroy (_hea_blob);

    this->has_font_extents = got_font_extents;

    this->blob = OT::Sanitizer<OT::_mtx>::sanitize (face->reference_table (_mtx_tag));

    /* Cap num_metrics() and num_advances() based on table length. */

    unsigned int len = hb_blob_get_length (this->blob);

    if (unlikely (this->num_advances * 4 > len))

      this->num_advances = len / 4;

    this->num_metrics = this->num_advances + (len - 4 * this->num_advances) / 2;

    /* We MUST set num_metrics to zero if num_advances is zero.

     * Our get_advance() depends on that. */

    if (unlikely (!this->num_advances))

    {

      this->num_metrics = this->num_advances = 0;

      hb_blob_destroy (this->blob);

      this->blob = hb_blob_get_empty ();

    }

    this->table = OT::Sanitizer<OT::_mtx>::lock_instance (this->blob);

  }

  inline void fini (void)

  {

    hb_blob_destroy (this->blob);

  }

  inline unsigned int get_advance (hb_codepoint_t glyph) const

  {

    if (unlikely (glyph >= this->num_metrics))

    {

      /* If this->num_metrics is zero, it means we don't have the metrics table

       * for this direction: return default advance.  Otherwise, it means that the

       * glyph index is out of bound: return zero. */

      if (this->num_metrics)

        return 0;

      else

        return this->default_advance;

    }

    if (glyph >= this->num_advances)

      glyph = this->num_advances - 1;

    return this->table->longMetric[glyph].advance;

  }

};

struct hb_ot_face_glyf_accelerator_t

{

  bool short_offset;

  unsigned int num_glyphs;

  const OT::loca *loca;

  const OT::glyf *glyf;

  hb_blob_t *loca_blob;

  hb_blob_t *glyf_blob;

  unsigned int glyf_len;

  inline void init (hb_face_t *face)

  {

    hb_blob_t *head_blob = OT::Sanitizer<OT::head>::sanitize (face->reference_table (HB_OT_TAG_head));

    const OT::head *head = OT::Sanitizer<OT::head>::lock_instance (head_blob);

    if ((unsigned int) head->indexToLocFormat > 1 || head->glyphDataFormat != 0)

    {

      /* Unknown format.  Leave num_glyphs=0, that takes care of disabling us. */

      hb_blob_destroy (head_blob);

      return;

    }

    this->short_offset = 0 == head->indexToLocFormat;

    hb_blob_destroy (head_blob);

    this->loca_blob = OT::Sanitizer<OT::loca>::sanitize (face->reference_table (HB_OT_TAG_loca));

    this->loca = OT::Sanitizer<OT::loca>::lock_instance (this->loca_blob);

    this->glyf_blob = OT::Sanitizer<OT::glyf>::sanitize (face->reference_table (HB_OT_TAG_glyf));

    this->glyf = OT::Sanitizer<OT::glyf>::lock_instance (this->glyf_blob);

    this->num_glyphs = MAX (1u, hb_blob_get_length (this->loca_blob) / (this->short_offset ? 2 : 4)) - 1;

    this->glyf_len = hb_blob_get_length (this->glyf_blob);

  }

  inline void fini (void)

  {

    hb_blob_destroy (this->loca_blob);

    hb_blob_destroy (this->glyf_blob);

  }

  inline bool get_extents (hb_codepoint_t glyph,

                           hb_glyph_extents_t *extents) const

  {

    if (unlikely (glyph >= this->num_glyphs))

      return false;

    unsigned int start_offset, end_offset;

    if (this->short_offset)

    {

      start_offset = 2 * this->loca->u.shortsZ[glyph];

      end_offset   = 2 * this->loca->u.shortsZ[glyph + 1];

    }

    else

    {

      start_offset = this->loca->u.longsZ[glyph];

      end_offset   = this->loca->u.longsZ[glyph + 1];

    }

    if (start_offset > end_offset || end_offset > this->glyf_len)

      return false;

    if (end_offset - start_offset < OT::glyfGlyphHeader::static_size)

      return true; /* Empty glyph; zero extents. */

    const OT::glyfGlyphHeader &glyph_header = OT::StructAtOffset<OT::glyfGlyphHeader> (this->glyf, start_offset);

    extents->x_bearing = MIN (glyph_header.xMin, glyph_header.xMax);

    extents->y_bearing = MAX (glyph_header.yMin, glyph_header.yMax);

    extents->width     = MAX (glyph_header.xMin, glyph_header.xMax) - extents->x_bearing;

    extents->height    = MIN (glyph_header.yMin, glyph_header.yMax) - extents->y_bearing;

    return true;

  }

};

struct hb_ot_face_cbdt_accelerator_t

{

  hb_blob_t *cblc_blob;

  hb_blob_t *cbdt_blob;

  const OT::CBLC *cblc;

  const OT::CBDT *cbdt;

  unsigned int cbdt_len;

  float upem;

  inline void init (hb_face_t *face)

  {

    upem = face->get_upem();

    cblc_blob = OT::Sanitizer<OT::CBLC>::sanitize (face->reference_table (HB_OT_TAG_CBLC));

    cbdt_blob = OT::Sanitizer<OT::CBDT>::sanitize (face->reference_table (HB_OT_TAG_CBDT));

    cbdt_len = hb_blob_get_length (cbdt_blob);

    if (hb_blob_get_length (cblc_blob) == 0) {

      cblc = NULL;

      cbdt = NULL;

      return;  /* Not a bitmap font. */

    }

    cblc = OT::Sanitizer<OT::CBLC>::lock_instance (cblc_blob);

    cbdt = OT::Sanitizer<OT::CBDT>::lock_instance (cbdt_blob);

  }

  inline void fini (void)

  {

    hb_blob_destroy (this->cblc_blob);

    hb_blob_destroy (this->cbdt_blob);

  }

  inline bool get_extents (hb_codepoint_t glyph, hb_glyph_extents_t *extents) const

  {

    unsigned int x_ppem = upem, y_ppem = upem; /* TODO Use font ppem if available. */

    if (cblc == NULL)

      return false;  // Not a color bitmap font.

    const OT::IndexSubtableRecord *subtable_record = this->cblc->find_table(glyph, &x_ppem, &y_ppem);

    if (subtable_record == NULL)

      return false;

    if (subtable_record->get_extents (extents))

      return true;

    unsigned int image_offset = 0, image_length = 0, image_format = 0;

    if (!subtable_record->get_image_data (glyph, &image_offset, &image_length, &image_format))

      return false;

    {

      /* TODO Move the following into CBDT struct when adding more formats. */

      if (unlikely (image_offset > cbdt_len || cbdt_len - image_offset < image_length))

        return false;

      switch (image_format)

      {

        case 17: {

          if (unlikely (image_length < OT::GlyphBitmapDataFormat17::min_size))

            return false;

          const OT::GlyphBitmapDataFormat17& glyphFormat17 =

              OT::StructAtOffset<OT::GlyphBitmapDataFormat17> (this->cbdt, image_offset);

          glyphFormat17.glyphMetrics.get_extents (extents);

        }

        break;

        default:

          // TODO: Support other image formats.

          return false;

      }

    }

    /* Convert to the font units. */

    extents->x_bearing *= upem / (float) x_ppem;

    extents->y_bearing *= upem / (float) y_ppem;

    extents->width *= upem / (float) x_ppem;

    extents->height *= upem / (float) y_ppem;

    return true;

  }

};

typedef bool (*hb_cmap_get_glyph_func_t) (const void *obj,

                                          hb_codepoint_t codepoint,

                                          hb_codepoint_t *glyph);

template <typename Type>

static inline bool get_glyph_from (const void *obj,

                                   hb_codepoint_t codepoint,

                                   hb_codepoint_t *glyph)

{

  const Type *typed_obj = (const Type *) obj;

  return typed_obj->get_glyph (codepoint, glyph);

}

template <typename Type>

static inline bool get_glyph_from_symbol (const void *obj,

                                          hb_codepoint_t codepoint,

                                          hb_codepoint_t *glyph)

{

  const Type *typed_obj = (const Type *) obj;

  if (likely (typed_obj->get_glyph (codepoint, glyph)))

    return true;

  if (codepoint <= 0x00FFu)

  {

    /* For symbol-encoded OpenType fonts, we duplicate the

     * U+F000..F0FF range at U+0000..U+00FF.  That's what

     * Windows seems to do, and that's hinted about at:

     * http://www.microsoft.com/typography/otspec/recom.htm

     * under "Non-Standard (Symbol) Fonts". */

    return typed_obj->get_glyph (0xF000u + codepoint, glyph);

  }

  return false;

}

struct hb_ot_face_cmap_accelerator_t

{

  hb_cmap_get_glyph_func_t get_glyph_func;

  const void *get_glyph_data;

  OT::CmapSubtableFormat4::accelerator_t format4_accel;

  const OT::CmapSubtableFormat14 *uvs_table;

  hb_blob_t *blob;

  inline void init (hb_face_t *face)

  {

    this->blob = OT::Sanitizer<OT::cmap>::sanitize (face->reference_table (HB_OT_TAG_cmap));

    const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);

    const OT::CmapSubtable *subtable = NULL;

    const OT::CmapSubtableFormat14 *subtable_uvs = NULL;

    bool symbol = false;

    /* 32-bit subtables. */

    if (!subtable) subtable = cmap->find_subtable (3, 10);

    if (!subtable) subtable = cmap->find_subtable (0, 6);

    if (!subtable) subtable = cmap->find_subtable (0, 4);

    /* 16-bit subtables. */

    if (!subtable) subtable = cmap->find_subtable (3, 1);

    if (!subtable) subtable = cmap->find_subtable (0, 3);

    if (!subtable) subtable = cmap->find_subtable (0, 2);

    if (!subtable) subtable = cmap->find_subtable (0, 1);

    if (!subtable) subtable = cmap->find_subtable (0, 0);

    if (!subtable)

    {

      subtable = cmap->find_subtable (3, 0);

      if (subtable) symbol = true;

    }

    /* Meh. */

    if (!subtable) subtable = &OT::Null(OT::CmapSubtable);

    /* UVS subtable. */

    if (!subtable_uvs)

    {

      const OT::CmapSubtable *st = cmap->find_subtable (0, 5);

      if (st && st->u.format == 14)

        subtable_uvs = &st->u.format14;

    }

    /* Meh. */

    if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtableFormat14);

    this->uvs_table = subtable_uvs;

    this->get_glyph_data = subtable;

    if (unlikely (symbol))

      this->get_glyph_func = get_glyph_from_symbol<OT::CmapSubtable>;

    else

      switch (subtable->u.format) {

      /* Accelerate format 4 and format 12. */

      default: this->get_glyph_func = get_glyph_from<OT::CmapSubtable>;         break;

      case 12: this->get_glyph_func = get_glyph_from<OT::CmapSubtableFormat12>; break;

      case  4:

        {

          this->format4_accel.init (&subtable->u.format4);

          this->get_glyph_data = &this->format4_accel;

          this->get_glyph_func = this->format4_accel.get_glyph_func;

        }

        break;

      }

  }

  inline void fini (void)

  {

    hb_blob_destroy (this->blob);

  }

  inline bool get_nominal_glyph (hb_codepoint_t  unicode,

                                 hb_codepoint_t *glyph) const

  {

    return this->get_glyph_func (this->get_glyph_data, unicode, glyph);

  }

  inline bool get_variation_glyph (hb_codepoint_t  unicode,

                                   hb_codepoint_t  variation_selector,

                                   hb_codepoint_t *glyph) const

  {

    switch (this->uvs_table->get_glyph_variant (unicode,

                                                variation_selector,

                                                glyph))

    {

      case OT::GLYPH_VARIANT_NOT_FOUND:         return false;

      case OT::GLYPH_VARIANT_FOUND:             return true;

      case OT::GLYPH_VARIANT_USE_DEFAULT:       break;

    }

    return get_nominal_glyph (unicode, glyph);

  }

};

template <typename T>

struct hb_lazy_loader_t

{

  inline void init (hb_face_t *face_)

  {

    face = face_;

    instance = NULL;

  }

  inline void fini (void)

  {

    if (instance && instance != &OT::Null(T))

    {

      instance->fini();

      free (instance);

    }

  }

  inline const T* operator-> (void) const

  {

  retry:

    T *p = (T *) hb_atomic_ptr_get (&instance);

    if (unlikely (!p))

    {

      p = (T *) calloc (1, sizeof (T));

      if (unlikely (!p))

        return &OT::Null(T);

      p->init (face);

      if (unlikely (!hb_atomic_ptr_cmpexch (const_cast<T **>(&instance), NULL, p)))

      {

        p->fini ();

        goto retry;

      }

    }

    return p;

  }

  private:

  hb_face_t *face;

  T *instance;

};

struct hb_ot_font_t

{

  hb_ot_face_cmap_accelerator_t cmap;

  hb_ot_face_metrics_accelerator_t h_metrics;

  hb_ot_face_metrics_accelerator_t v_metrics;

  hb_lazy_loader_t<hb_ot_face_glyf_accelerator_t> glyf;

  hb_lazy_loader_t<hb_ot_face_cbdt_accelerator_t> cbdt;

};

static hb_ot_font_t *

_hb_ot_font_create (hb_face_t *face)

{

  hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));

  if (unlikely (!ot_font))

    return NULL;

  ot_font->cmap.init (face);

  ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, HB_OT_TAG_os2);

  ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, HB_TAG_NONE,

                           ot_font->h_metrics.ascender - ot_font->h_metrics.descender); /* TODO Can we do this lazily? */

  ot_font->glyf.init (face);

  ot_font->cbdt.init (face);

  return ot_font;

}

static void

_hb_ot_font_destroy (hb_ot_font_t *ot_font)

{

  ot_font->cmap.fini ();

  ot_font->h_metrics.fini ();

  ot_font->v_metrics.fini ();

  ot_font->glyf.fini ();

  ot_font->cbdt.fini ();

  free (ot_font);

}

static hb_bool_t