1 /*
   2  * Copyright © 2018 Adobe Inc.
   3  *
   4  *  This is part of HarfBuzz, a text shaping library.
   5  *
   6  * Permission is hereby granted, without written agreement and without
   7  * license or royalty fees, to use, copy, modify, and distribute this
   8  * software and its documentation for any purpose, provided that the
   9  * above copyright notice and the following two paragraphs appear in
  10  * all copies of this software.
  11  *
  12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  16  * DAMAGE.
  17  *
  18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  23  *
  24  * Adobe Author(s): Michiharu Ariza
  25  */
  26 
  27 #ifndef HB_OT_VORG_TABLE_HH
  28 #define HB_OT_VORG_TABLE_HH
  29 
  30 #include "hb-open-type.hh"
  31 
  32 /*
  33  * VORG -- Vertical Origin Table
  34  * https://docs.microsoft.com/en-us/typography/opentype/spec/vorg
  35  */
  36 #define HB_OT_TAG_VORG HB_TAG('V','O','R','G')
  37 
  38 namespace OT {
  39 
  40 struct VertOriginMetric
  41 {
  42   int cmp (hb_codepoint_t g) const { return glyph.cmp (g); }
  43 
  44   bool sanitize (hb_sanitize_context_t *c) const
  45   {
  46     TRACE_SANITIZE (this);
  47     return_trace (c->check_struct (this));
  48   }
  49 
  50   public:
  51   GlyphID       glyph;
  52   FWORD         vertOriginY;
  53 
  54   public:
  55   DEFINE_SIZE_STATIC (4);
  56 };
  57 
  58 struct VORG
  59 {
  60   static constexpr hb_tag_t tableTag = HB_OT_TAG_VORG;
  61 
  62   bool has_data () const { return version.to_int (); }
  63 
  64   int get_y_origin (hb_codepoint_t glyph) const
  65   {
  66     unsigned int i;
  67     if (!vertYOrigins.bfind (glyph, &i))
  68       return defaultVertOriginY;
  69     return vertYOrigins[i].vertOriginY;
  70   }
  71 
  72   bool _subset (const hb_subset_plan_t *plan HB_UNUSED,
  73                 const VORG *vorg_table,
  74                 const hb_vector_t<VertOriginMetric> &subset_metrics,
  75                 unsigned int dest_sz,
  76                 void *dest) const
  77   {
  78     hb_serialize_context_t c (dest, dest_sz);
  79 
  80     VORG *subset_table = c.start_serialize<VORG> ();
  81     if (unlikely (!c.extend_min (*subset_table)))
  82       return false;
  83 
  84     subset_table->version.major.set (1);
  85     subset_table->version.minor.set (0);
  86 
  87     subset_table->defaultVertOriginY.set (vorg_table->defaultVertOriginY);
  88     subset_table->vertYOrigins.len.set (subset_metrics.length);
  89 
  90     bool success = true;
  91     if (subset_metrics.length > 0)
  92     {
  93       unsigned int  size = VertOriginMetric::static_size * subset_metrics.length;
  94       VertOriginMetric  *metrics = c.allocate_size<VertOriginMetric> (size);
  95       if (likely (metrics != nullptr))
  96         memcpy (metrics, &subset_metrics[0], size);
  97       else
  98         success = false;
  99     }
 100     c.end_serialize ();
 101 
 102     return success;
 103   }
 104 
 105   bool subset (hb_subset_plan_t *plan) const
 106   {
 107     hb_blob_t *vorg_blob = hb_sanitize_context_t().reference_table<VORG> (plan->source);
 108     const VORG *vorg_table = vorg_blob->as<VORG> ();
 109 
 110     /* count the number of glyphs to be included in the subset table */
 111     hb_vector_t<VertOriginMetric> subset_metrics;
 112     subset_metrics.init ();
 113     unsigned int glyph = 0;
 114     unsigned int i = 0;
 115     while ((glyph < plan->glyphs.length) && (i < vertYOrigins.len))
 116     {
 117       if (plan->glyphs[glyph] > vertYOrigins[i].glyph)
 118         i++;
 119       else if (plan->glyphs[glyph] < vertYOrigins[i].glyph)
 120         glyph++;
 121       else
 122       {
 123         VertOriginMetric *metrics = subset_metrics.push ();
 124         metrics->glyph.set (glyph);
 125         metrics->vertOriginY.set (vertYOrigins[i].vertOriginY);
 126         glyph++;
 127         i++;
 128       }
 129     }
 130 
 131     /* alloc the new table */
 132     unsigned int dest_sz = VORG::min_size + VertOriginMetric::static_size * subset_metrics.length;
 133     void *dest = (void *) malloc (dest_sz);
 134     if (unlikely (!dest))
 135     {
 136       subset_metrics.fini ();
 137       hb_blob_destroy (vorg_blob);
 138       return false;
 139     }
 140 
 141     /* serialize the new table */
 142     if (!_subset (plan, vorg_table, subset_metrics, dest_sz, dest))
 143     {
 144       subset_metrics.fini ();
 145       free (dest);
 146       hb_blob_destroy (vorg_blob);
 147       return false;
 148     }
 149 
 150     hb_blob_t *result = hb_blob_create ((const char *)dest,
 151                                         dest_sz,
 152                                         HB_MEMORY_MODE_READONLY,
 153                                         dest,
 154                                         free);
 155     bool success = plan->add_table (HB_OT_TAG_VORG, result);
 156     hb_blob_destroy (result);
 157     subset_metrics.fini ();
 158     hb_blob_destroy (vorg_blob);
 159     return success;
 160   }
 161 
 162   bool sanitize (hb_sanitize_context_t *c) const
 163   {
 164     TRACE_SANITIZE (this);
 165     return_trace (c->check_struct (this) &&
 166                   version.major == 1 &&
 167                   vertYOrigins.sanitize (c));
 168   }
 169 
 170   protected:
 171   FixedVersion<>        version;                /* Version of VORG table. Set to 0x00010000u. */
 172   FWORD                 defaultVertOriginY;     /* The default vertical origin. */
 173   SortedArrayOf<VertOriginMetric>
 174                         vertYOrigins;           /* The array of vertical origins. */
 175 
 176   public:
 177   DEFINE_SIZE_ARRAY(8, vertYOrigins);
 178 };
 179 } /* namespace OT */
 180 
 181 #endif /* HB_OT_VORG_TABLE_HH */