230 lines
7.0 KiB
C++
230 lines
7.0 KiB
C++
/*
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* Copyright © 2011,2012,2013 Google, Inc.
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* Copyright © 2021 Khaled Hosny
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Google Author(s): Behdad Esfahbod
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*/
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#ifndef HB_MS_FEATURE_RANGES_HH
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#define HB_MS_FEATURE_RANGES_HH
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#include "hb.hh"
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typedef struct hb_ms_feature_t {
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uint32_t tag_le;
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uint32_t value;
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} hb_ms_feature_t;
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typedef struct hb_ms_features_t {
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hb_ms_feature_t *features;
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uint32_t num_features;
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} hb_ms_features_t;
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struct hb_ms_active_feature_t {
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hb_ms_feature_t fea;
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unsigned int order;
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HB_INTERNAL static int cmp (const void *pa, const void *pb) {
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const auto *a = (const hb_ms_active_feature_t *) pa;
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const auto *b = (const hb_ms_active_feature_t *) pb;
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return a->fea.tag_le < b->fea.tag_le ? -1 : a->fea.tag_le > b->fea.tag_le ? 1 :
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a->order < b->order ? -1 : a->order > b->order ? 1 :
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a->fea.value < b->fea.value ? -1 : a->fea.value > b->fea.value ? 1 :
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0;
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}
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bool operator== (const hb_ms_active_feature_t& f) const
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{ return cmp (this, &f) == 0; }
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};
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struct hb_ms_feature_event_t {
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unsigned int index;
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bool start;
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hb_ms_active_feature_t feature;
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HB_INTERNAL static int cmp (const void *pa, const void *pb)
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{
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const auto *a = (const hb_ms_feature_event_t *) pa;
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const auto *b = (const hb_ms_feature_event_t *) pb;
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return a->index < b->index ? -1 : a->index > b->index ? 1 :
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a->start < b->start ? -1 : a->start > b->start ? 1 :
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hb_ms_active_feature_t::cmp (&a->feature, &b->feature);
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}
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};
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struct hb_ms_range_record_t {
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hb_ms_features_t features;
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unsigned int index_first; /* == start */
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unsigned int index_last; /* == end - 1 */
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};
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static inline bool
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hb_ms_setup_features (const hb_feature_t *features,
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unsigned int num_features,
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hb_vector_t<hb_ms_feature_t> &feature_records, /* OUT */
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hb_vector_t<hb_ms_range_record_t> &range_records /* OUT */)
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{
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feature_records.shrink(0);
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range_records.shrink(0);
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/* Sort features by start/end events. */
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hb_vector_t<hb_ms_feature_event_t> feature_events;
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for (unsigned int i = 0; i < num_features; i++)
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{
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hb_ms_active_feature_t feature;
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feature.fea.tag_le = hb_uint32_swap (features[i].tag);
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feature.fea.value = features[i].value;
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feature.order = i;
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hb_ms_feature_event_t *event;
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event = feature_events.push ();
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event->index = features[i].start;
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event->start = true;
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event->feature = feature;
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event = feature_events.push ();
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event->index = features[i].end;
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event->start = false;
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event->feature = feature;
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}
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feature_events.qsort ();
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/* Add a strategic final event. */
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{
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hb_ms_active_feature_t feature;
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feature.fea.tag_le = 0;
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feature.fea.value = 0;
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feature.order = num_features + 1;
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auto *event = feature_events.push ();
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event->index = 0; /* This value does magic. */
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event->start = false;
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event->feature = feature;
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}
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/* Scan events and save features for each range. */
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hb_vector_t<hb_ms_active_feature_t> active_features;
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unsigned int last_index = 0;
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for (unsigned int i = 0; i < feature_events.length; i++)
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{
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auto *event = &feature_events[i];
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if (event->index != last_index)
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{
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/* Save a snapshot of active features and the range. */
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auto *range = range_records.push ();
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auto offset = feature_records.length;
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active_features.qsort ();
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for (unsigned int j = 0; j < active_features.length; j++)
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{
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if (!j || active_features[j].fea.tag_le != feature_records[feature_records.length - 1].tag_le)
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{
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feature_records.push (active_features[j].fea);
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}
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else
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{
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/* Overrides value for existing feature. */
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feature_records[feature_records.length - 1].value = active_features[j].fea.value;
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}
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}
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/* Will convert to pointer after all is ready, since feature_records.array
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* may move as we grow it. */
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range->features.features = reinterpret_cast<hb_ms_feature_t *> (offset);
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range->features.num_features = feature_records.length - offset;
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range->index_first = last_index;
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range->index_last = event->index - 1;
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last_index = event->index;
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}
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if (event->start)
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{
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active_features.push (event->feature);
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}
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else
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{
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auto *feature = active_features.lsearch (event->feature);
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if (feature)
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active_features.remove (feature - active_features.arrayZ);
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}
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}
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if (!range_records.length) /* No active feature found. */
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num_features = 0;
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/* Fixup the pointers. */
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for (unsigned int i = 0; i < range_records.length; i++)
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{
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auto *range = &range_records[i];
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range->features.features = (hb_ms_feature_t *) feature_records + reinterpret_cast<uintptr_t> (range->features.features);
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}
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return !!num_features;
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}
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static inline void
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hb_ms_make_feature_ranges (hb_vector_t<hb_ms_feature_t> &feature_records,
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hb_vector_t<hb_ms_range_record_t> &range_records,
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unsigned int chars_offset,
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unsigned int chars_len,
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uint16_t *log_clusters,
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hb_vector_t<hb_ms_features_t*> &range_features, /* OUT */
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hb_vector_t<uint32_t> &range_counts /* OUT */)
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{
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range_features.shrink (0);
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range_counts.shrink (0);
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auto *last_range = &range_records[0];
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for (unsigned int i = chars_offset; i < chars_len; i++)
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{
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auto *range = last_range;
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while (log_clusters[i] < range->index_first)
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range--;
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while (log_clusters[i] > range->index_last)
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range++;
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if (!range_features.length ||
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&range->features != range_features[range_features.length - 1])
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{
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auto **features = range_features.push ();
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auto *c = range_counts.push ();
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if (unlikely (!features || !c))
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{
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range_features.shrink (0);
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range_counts.shrink (0);
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break;
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}
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*features = &range->features;
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*c = 1;
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}
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else
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{
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range_counts[range_counts.length - 1]++;
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}
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last_range = range;
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}
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}
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#endif /* HB_MS_FEATURE_RANGES_HH */
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