/*
* 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"
/* Variations of this code exist in hb-coretext.cc as well
* as hb-aat-map.cc... */
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_ordered (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 */
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