summaryrefslogtreecommitdiff
path: root/Build/source/libs/harfbuzz/harfbuzz-src/src/hb-ms-feature-ranges.hh
blob: d40fdeaa824796886737d83a23af0e54859f1a04 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
/*
 * Copyright © 2011,2012,2013  Google, Inc.
 * Copyright © 2021  Khaled Hosny
 *
 *  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_MS_FEATURE_RANGES_HH
#define HB_MS_FEATURE_RANGES_HH

#include "hb.hh"

typedef struct hb_ms_feature_t {
  uint32_t tag_le;
  uint32_t value;
} hb_ms_feature_t;

typedef struct hb_ms_features_t {
  hb_ms_feature_t *features;
  uint32_t         num_features;
} hb_ms_features_t;

struct hb_ms_active_feature_t {
  hb_ms_feature_t fea;
  unsigned int order;

  HB_INTERNAL static int cmp (const void *pa, const void *pb) {
    const auto *a = (const hb_ms_active_feature_t *) pa;
    const auto *b = (const hb_ms_active_feature_t *) pb;
    return a->fea.tag_le < b->fea.tag_le ? -1 : a->fea.tag_le > b->fea.tag_le ? 1 :
	   a->order < b->order ? -1 : a->order > b->order ? 1 :
	   a->fea.value < b->fea.value ? -1 : a->fea.value > b->fea.value ? 1 :
	   0;
  }
  bool operator== (const hb_ms_active_feature_t& f) const
  { return cmp (this, &f) == 0; }
};

struct hb_ms_feature_event_t {
  unsigned int index;
  bool start;
  hb_ms_active_feature_t feature;

  HB_INTERNAL static int cmp (const void *pa, const void *pb)
  {
    const auto *a = (const hb_ms_feature_event_t *) pa;
    const auto *b = (const hb_ms_feature_event_t *) pb;
    return a->index < b->index ? -1 : a->index > b->index ? 1 :
	   a->start < b->start ? -1 : a->start > b->start ? 1 :
	   hb_ms_active_feature_t::cmp (&a->feature, &b->feature);
  }
};

struct hb_ms_range_record_t {
  hb_ms_features_t features;
  unsigned int index_first; /* == start */
  unsigned int index_last;  /* == end - 1 */
};

static inline bool
hb_ms_setup_features (const hb_feature_t                *features,
		      unsigned int                       num_features,
		      hb_vector_t<hb_ms_feature_t>      &feature_records, /* OUT */
		      hb_vector_t<hb_ms_range_record_t> &range_records /* OUT */)
{
  feature_records.shrink(0);
  range_records.shrink(0);

  /* Sort features by start/end events. */
  hb_vector_t<hb_ms_feature_event_t> feature_events;
  for (unsigned int i = 0; i < num_features; i++)
  {
    hb_ms_active_feature_t feature;
    feature.fea.tag_le = hb_uint32_swap (features[i].tag);
    feature.fea.value = features[i].value;
    feature.order = i;

    hb_ms_feature_event_t *event;

    event = feature_events.push ();
    event->index = features[i].start;
    event->start = true;
    event->feature = feature;

    event = feature_events.push ();
    event->index = features[i].end;
    event->start = false;
    event->feature = feature;
  }
  feature_events.qsort ();
  /* Add a strategic final event. */
  {
    hb_ms_active_feature_t feature;
    feature.fea.tag_le = 0;
    feature.fea.value = 0;
    feature.order = num_features + 1;

    auto *event = feature_events.push ();
    event->index = 0; /* This value does magic. */
    event->start = false;
    event->feature = feature;
  }

  /* Scan events and save features for each range. */
  hb_vector_t<hb_ms_active_feature_t> active_features;
  unsigned int last_index = 0;
  for (unsigned int i = 0; i < feature_events.length; i++)
  {
    auto *event = &feature_events[i];

    if (event->index != last_index)
    {
      /* Save a snapshot of active features and the range. */
      auto *range = range_records.push ();
      auto offset = feature_records.length;

      active_features.qsort ();
      for (unsigned int j = 0; j < active_features.length; j++)
      {
        if (!j || active_features[j].fea.tag_le != feature_records[feature_records.length - 1].tag_le)
        {
          feature_records.push (active_features[j].fea);
        }
        else
        {
          /* Overrides value for existing feature. */
          feature_records[feature_records.length - 1].value = active_features[j].fea.value;
        }
      }

      /* Will convert to pointer after all is ready, since feature_records.array
       * may move as we grow it. */
      range->features.features = reinterpret_cast<hb_ms_feature_t *> (offset);
      range->features.num_features = feature_records.length - offset;
      range->index_first = last_index;
      range->index_last  = event->index - 1;

      last_index = event->index;
    }

    if (event->start)
    {
      active_features.push (event->feature);
    }
    else
    {
      auto *feature = active_features.lsearch (event->feature);
      if (feature)
        active_features.remove (feature - active_features.arrayZ);
    }
  }

  if (!range_records.length) /* No active feature found. */
    num_features = 0;

  /* Fixup the pointers. */
  for (unsigned int i = 0; i < range_records.length; i++)
  {
    auto *range = &range_records[i];
    range->features.features = (hb_ms_feature_t *) feature_records + reinterpret_cast<uintptr_t> (range->features.features);
  }

  return !!num_features;
}

static inline void
hb_ms_make_feature_ranges (hb_vector_t<hb_ms_feature_t>      &feature_records,
			   hb_vector_t<hb_ms_range_record_t> &range_records,
			   unsigned int                       chars_offset,
			   unsigned int                       chars_len,
			   uint16_t                          *log_clusters,
			   hb_vector_t<hb_ms_features_t*>    &range_features, /* OUT */
			   hb_vector_t<uint32_t>             &range_counts /* OUT */)
{
  range_features.shrink (0);
  range_counts.shrink (0);

  auto *last_range = &range_records[0];
  for (unsigned int i = chars_offset; i < chars_len; i++)
  {
    auto *range = last_range;
    while (log_clusters[i] < range->index_first)
      range--;
    while (log_clusters[i] > range->index_last)
      range++;
    if (!range_features.length ||
        &range->features != range_features[range_features.length - 1])
    {
      auto **features = range_features.push ();
      auto *c = range_counts.push ();
      if (unlikely (!features || !c))
      {
        range_features.shrink (0);
        range_counts.shrink (0);
        break;
      }
      *features = &range->features;
      *c = 1;
    }
    else
    {
      range_counts[range_counts.length - 1]++;
    }

    last_range = range;
  }
}

#endif /* HB_MS_FEATURE_RANGES_HH */