Towards a mask allocator
This commit is contained in:
Behdad Esfahbod
parent
81c5e8724b
commit
0e235d0fc9
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@ -1,5 +1,5 @@
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/*
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* Copyright (C) 2009 Red Hat, Inc.
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* Copyright (C) 2009,2010 Red Hat, Inc.
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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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@ -28,6 +28,8 @@
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#include "hb-buffer-private.hh"
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#include "hb-open-type-private.hh"
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#include "hb-ot-layout.h"
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/* XXX vertical */
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@ -95,102 +97,159 @@ cmp_lookups (const void *p1, const void *p2)
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#define MAX_FEATURES 100
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struct feature_info {
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struct hb_mask_allocator_t {
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struct feature_info_t {
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hb_tag_t tag;
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unsigned int index;
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unsigned int value;
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bool global;
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static int
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cmp (const void *p1, const void *p2)
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{
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const feature_info_t *a = (const feature_info_t *) p1;
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const feature_info_t *b = (const feature_info_t *) p2;
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if (a->tag != b->tag)
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return a->tag < b->tag ? -1 : 1;
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return p1 < p2 ? -1 : 1;
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}
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};
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struct feature_map_t {
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hb_tag_t tag; /* should be first */
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unsigned int index;
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unsigned int shift;
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hb_mask_t mask;
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};
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struct feature_setup_state {
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hb_mask_t global_mask;
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unsigned int next_bit;
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unsigned int count;
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feature_info info[MAX_FEATURES];
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};
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static int
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cmp (const void *p1, const void *p2)
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{
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const feature_map_t *a = (const feature_map_t *) p1;
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const feature_map_t *b = (const feature_map_t *) p2;
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static void
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collect_feature_info(hb_buffer_t *buffer,
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hb_face_t *face,
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return a->tag < b->tag ? -1 : a->tag > b->tag ? 1 : 0;
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}
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};
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hb_mask_allocator_t (hb_face_t *face,
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hb_tag_t table_tag,
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unsigned int script_index,
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unsigned int language_index,
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const hb_feature_t &feature,
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feature_setup_state &fss,
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const hb_feature_t *features,
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unsigned int num_features)
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{
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if (fss.count == MAX_FEATURES)
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return; // FIXME - make the feature_info array growable?
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unsigned int num_features) :
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face (face),
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table_tag (table_tag),
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script_index (script_index),
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language_index (language_index),
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count (0)
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{
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if (!num_features)
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return;
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unsigned int i, feature_index;
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/* Add features in reverse order */
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for (unsigned int i = num_features - 1, count = 0; count < num_features; i--, count++) {
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const hb_feature_t *feature = &features[i];
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feature_info_t *info = &infos[count];
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info->tag = feature->tag;
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info->value = feature->value;
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info->global = (feature->start == 0 && feature->end == (unsigned int) -1);
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}
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}
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void add_binary_feature (hb_tag_t tag,
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bool global)
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{
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feature_info_t *info = &infos[count++];
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info->tag = tag;
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info->value = 1;
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info->global = global;
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}
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void compile (void)
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{
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global_mask = 0;
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next_bit = MASK_BITS_USED;
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if (!count)
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return;
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qsort (infos, count, sizeof (infos[0]), feature_info_t::cmp);
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unsigned int j = 0;
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for (unsigned int i = 1; i < count; i++)
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if (infos[i].tag != infos[j].tag)
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infos[++j] = infos[i];
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else {
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if (!infos[j].global)
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infos[j].value = MAX (infos[j].value, infos[i].value);
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}
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count = j + 1;
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/* Allocate bits now */
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j = 0;
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for (unsigned int i = 0; i < count; i++) {
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const feature_info_t *info = &infos[i];
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unsigned int bits_needed;
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if (info->global && info->value == 1)
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/* Uses the global bit */
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bits_needed = 0;
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else
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bits_needed = _hb_bit_storage (info->value);
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if (!info->value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
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continue; /* Feature disabled, or not enough bits. */
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unsigned int feature_index;
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if (!hb_ot_layout_language_find_feature (face, table_tag, script_index, language_index,
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feature.tag, &feature_index))
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return;
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fss.info[fss.count].tag = feature.tag;
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fss.info[fss.count].index = feature_index;
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// check if we have already allocated mask bits for this feature tag
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for (i = 0; i < fss.count; ++i)
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{
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if (fss.info[i].tag == feature.tag)
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{
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fss.info[fss.count].mask = fss.info[i].mask;
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fss.info[fss.count].value = feature.value << _hb_ctz(fss.info[fss.count].mask);
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if (feature.start == 0 && feature.end == (unsigned int) -1)
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fss.global_mask |= fss.info[fss.count].value;
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else
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buffer->set_masks(fss.info[fss.count].value, fss.info[fss.count].mask, feature.start, feature.end);
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++fss.count;
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return;
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}
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}
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// check if the feature occurs in remaining user features, as it might have a larger value there
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hb_bool_t always_on = (feature.value == 1 && feature.start == 0 && feature.end == (unsigned int)-1);
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unsigned int max_value = feature.value;
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for (i = 0; i < num_features; ++i)
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{
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if (features[i].tag != feature.tag)
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info->tag, &feature_index))
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continue;
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if (features[i].value > max_value)
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max_value = features[i].value;
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else if (features[i].value == 0 && features[i].start == 0 && features[i].end == (unsigned int)-1)
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max_value = 0;
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feature_map_t *map = &maps[j++];
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map->tag = info->tag;
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map->index = feature_index;
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if (info->global && info->value == 1) {
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/* Uses the global bit */
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map->shift = 0;
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map->mask = 1;
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} else {
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map->shift = next_bit;
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map->mask = (1 << (next_bit + bits_needed)) - (1 << next_bit);
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next_bit += bits_needed;
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}
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if (always_on && max_value == 1)
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{
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fss.info[fss.count].value = 1;
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fss.info[fss.count].mask = 1;
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fss.global_mask |= 1;
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++fss.count;
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return;
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if (info->global && map->mask != 1)
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global_mask |= map->mask;
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}
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count = j;
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}
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// need to allocate specific mask bit(s) for this feature
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unsigned int bits_needed = _hb_bit_storage(max_value);
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if (!bits_needed || fss.next_bit + bits_needed > 8 * sizeof (hb_mask_t))
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{
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fss.info[fss.count].value = 0;
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fss.info[fss.count].mask = 0;
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++fss.count;
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return; // feature is disabled, just omit it; or
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// not enough bits available in the mask, ignore this feature :(
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hb_mask_t get_global_mask (void) { return global_mask; }
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const feature_map_t *find_feature (hb_tag_t tag) const {
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static const feature_map_t off_map = { HB_TAG_NONE, Index::NOT_FOUND_INDEX, 0, 0 };
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const feature_map_t *map = (const feature_map_t *) bsearch (&tag, maps, count, sizeof (maps[0]), feature_map_t::cmp);
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return map ? map : &off_map;
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}
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// store the newly-allocated mask (in case further feature requests use the same tag)
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// and shift the value into the right position
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fss.info[fss.count].value = feature.value << fss.next_bit;
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fss.info[fss.count].mask = (1 << (fss.next_bit + bits_needed)) - (1 << fss.next_bit);
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if (feature.start == 0 && feature.end == (unsigned int) -1)
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fss.global_mask |= fss.info[fss.count].value;
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else
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buffer->set_masks(fss.info[fss.count].value, fss.info[fss.count].mask, feature.start, feature.end);
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fss.next_bit += bits_needed;
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++fss.count;
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}
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private:
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hb_face_t *face;
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hb_tag_t table_tag;
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unsigned int script_index;
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unsigned int language_index;
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unsigned int count;
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feature_info_t infos[MAX_FEATURES];
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feature_map_t maps[MAX_FEATURES];
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hb_mask_t global_mask;
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unsigned int next_bit;
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};
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static void
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setup_lookups (hb_face_t *face,
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@ -218,29 +277,53 @@ setup_lookups (hb_face_t *face,
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&feature_index))
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add_feature (face, table_tag, feature_index, 1, lookups, num_lookups, room_lookups);
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// for features that may be turned on/off or have value > 1,
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// we need to allocate bits in the mask
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feature_setup_state fss;
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fss.global_mask = 0;
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fss.next_bit = MASK_BITS_USED;
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fss.count = 0;
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hb_feature_t feature = { 0, 1, 0, (unsigned int)-1 };
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hb_mask_allocator_t allocator (face, table_tag, script_index, language_index, features, num_features);
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switch (original_direction) {
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case HB_DIRECTION_LTR:
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feature.tag = HB_TAG ('l','t','r','a');
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collect_feature_info(buffer, face, table_tag, script_index, language_index,
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feature, fss, features, num_features);
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feature.tag = HB_TAG ('l','t','r','m');
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collect_feature_info(buffer, face, table_tag, script_index, language_index,
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feature, fss, features, num_features);
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allocator.add_binary_feature (HB_TAG ('l','t','r','a'), true);
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allocator.add_binary_feature (HB_TAG ('l','t','r','m'), true);
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break;
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case HB_DIRECTION_RTL:
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feature.tag = HB_TAG ('r','t','l','a');
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collect_feature_info(buffer, face, table_tag, script_index, language_index,
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feature, fss, features, num_features);
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allocator.add_binary_feature (HB_TAG ('r','t','l','a'), true);
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//allocator.add_binary_feature (HB_TAG ('r','t','l','m'), false);
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allocator.add_binary_feature (HB_TAG ('r','t','l','m'), true);
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break;
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case HB_DIRECTION_TTB:
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case HB_DIRECTION_BTT:
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default:
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break;
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}
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for (i = 0; i < ARRAY_LENGTH (default_features); i++)
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allocator.add_binary_feature (default_features[i], true);
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/* Compile features */
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allocator.compile ();
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/* Gather lookup indices for features and set buffer masks at the same time */
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const hb_mask_allocator_t::feature_map_t *map;
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hb_mask_t global_mask = allocator.get_global_mask ();
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if (global_mask)
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buffer->set_masks (global_mask, global_mask, 0, (unsigned int) -1);
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switch (original_direction) {
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case HB_DIRECTION_LTR:
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map = allocator.find_feature (HB_TAG ('l','t','r','a'));
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add_feature (face, table_tag, map->index, map->mask, lookups, num_lookups, room_lookups);
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map = allocator.find_feature (HB_TAG ('l','t','r','m'));
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add_feature (face, table_tag, map->index, map->mask, lookups, num_lookups, room_lookups);
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break;
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case HB_DIRECTION_RTL:
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map = allocator.find_feature (HB_TAG ('r','t','l','a'));
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add_feature (face, table_tag, map->index, map->mask, lookups, num_lookups, room_lookups);
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//map = allocator.find_feature (HB_TAG ('r','t','l','m'));
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add_feature (face, table_tag, map->index, MASK_RTLM, lookups, num_lookups, room_lookups);
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break;
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case HB_DIRECTION_TTB:
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case HB_DIRECTION_BTT:
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@ -250,23 +333,21 @@ setup_lookups (hb_face_t *face,
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for (i = 0; i < ARRAY_LENGTH (default_features); i++)
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{
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feature.tag = default_features[i];
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collect_feature_info(buffer, face, table_tag, script_index, language_index,
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feature, fss, features, num_features);
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map = allocator.find_feature (default_features[i]);
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add_feature (face, table_tag, map->index, map->mask, lookups, num_lookups, room_lookups);
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}
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for (i = 0; i < num_features; i++)
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{
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collect_feature_info(buffer, face, table_tag, script_index, language_index,
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features[i], fss, features + i + 1, num_features - i - 1);
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hb_feature_t *feature = &features[i];
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map = allocator.find_feature (feature->tag);
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add_feature (face, table_tag, map->index, map->mask, lookups, num_lookups, room_lookups);
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if (!(feature->start == 0 && feature->end == (unsigned int)-1))
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buffer->set_masks (features[i].value << map->shift, map->mask, feature->start, feature->end);
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}
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for (i = 0; i < fss.count; ++i)
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if (fss.info[i].mask)
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add_feature (face, table_tag, fss.info[i].index, fss.info[i].mask, lookups, num_lookups, room_lookups);
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if (fss.global_mask > 1) // the 0x01 bit was set by clear_masks()
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buffer->set_masks (fss.global_mask, fss.global_mask, 0, (unsigned int) -1);
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/* Sort lookups and merge duplicates */
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qsort (lookups, *num_lookups, sizeof (lookups[0]), cmp_lookups);
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