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Diffstat (limited to 'src/3rdparty/harfbuzz-ng/src/hb-bit-set.hh')
| -rw-r--r-- | src/3rdparty/harfbuzz-ng/src/hb-bit-set.hh | 982 |
1 files changed, 982 insertions, 0 deletions
diff --git a/src/3rdparty/harfbuzz-ng/src/hb-bit-set.hh b/src/3rdparty/harfbuzz-ng/src/hb-bit-set.hh new file mode 100644 index 0000000000..5f4c6f0afe --- /dev/null +++ b/src/3rdparty/harfbuzz-ng/src/hb-bit-set.hh @@ -0,0 +1,982 @@ +/* + * Copyright © 2012,2017 Google, Inc. + * Copyright © 2021 Behdad Esfahbod + * + * 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_BIT_SET_HH +#define HB_BIT_SET_HH + +#include "hb.hh" +#include "hb-bit-page.hh" + + +struct hb_bit_set_t +{ + hb_bit_set_t () = default; + ~hb_bit_set_t () = default; + + hb_bit_set_t (const hb_bit_set_t& other) : hb_bit_set_t () { set (other, true); } + hb_bit_set_t ( hb_bit_set_t&& other) noexcept : hb_bit_set_t () { hb_swap (*this, other); } + hb_bit_set_t& operator= (const hb_bit_set_t& other) { set (other); return *this; } + hb_bit_set_t& operator= (hb_bit_set_t&& other) noexcept { hb_swap (*this, other); return *this; } + friend void swap (hb_bit_set_t &a, hb_bit_set_t &b) noexcept + { + if (likely (!a.successful || !b.successful)) + return; + hb_swap (a.population, b.population); + hb_swap (a.last_page_lookup, b.last_page_lookup); + hb_swap (a.page_map, b.page_map); + hb_swap (a.pages, b.pages); + } + + void init () + { + successful = true; + population = 0; + last_page_lookup = 0; + page_map.init (); + pages.init (); + } + void fini () + { + page_map.fini (); + pages.fini (); + } + + using page_t = hb_bit_page_t; + struct page_map_t + { + int cmp (const page_map_t &o) const { return cmp (o.major); } + int cmp (uint32_t o_major) const { return (int) o_major - (int) major; } + + uint32_t major; + uint32_t index; + }; + + bool successful = true; /* Allocations successful */ + mutable unsigned int population = 0; + mutable hb_atomic_int_t last_page_lookup = 0; + hb_sorted_vector_t<page_map_t> page_map; + hb_vector_t<page_t> pages; + + void err () { if (successful) successful = false; } /* TODO Remove */ + bool in_error () const { return !successful; } + + bool resize (unsigned int count, bool clear = true, bool exact_size = false) + { + if (unlikely (!successful)) return false; + + if (pages.length == 0 && count == 1) + exact_size = true; // Most sets are small and local + + if (unlikely (!pages.resize (count, clear, exact_size) || !page_map.resize (count, clear, exact_size))) + { + pages.resize (page_map.length, clear, exact_size); + successful = false; + return false; + } + return true; + } + + void alloc (unsigned sz) + { + sz >>= (page_t::PAGE_BITS_LOG_2 - 1); + pages.alloc (sz); + page_map.alloc (sz); + } + + void reset () + { + successful = true; + clear (); + } + + void clear () + { + resize (0); + if (likely (successful)) + population = 0; + } + bool is_empty () const + { + unsigned int count = pages.length; + for (unsigned int i = 0; i < count; i++) + if (!pages[i].is_empty ()) + return false; + return true; + } + explicit operator bool () const { return !is_empty (); } + + uint32_t hash () const + { + uint32_t h = 0; + for (auto &map : page_map) + { + auto &page = pages.arrayZ[map.index]; + if (unlikely (page.is_empty ())) continue; + h = h * 31 + hb_hash (map.major) + hb_hash (page); + } + return h; + } + + private: + void dirty () { population = UINT_MAX; } + public: + + void add (hb_codepoint_t g) + { + if (unlikely (!successful)) return; + if (unlikely (g == INVALID)) return; + dirty (); + page_t *page = page_for (g, true); if (unlikely (!page)) return; + page->add (g); + } + bool add_range (hb_codepoint_t a, hb_codepoint_t b) + { + if (unlikely (!successful)) return true; /* https://github.com/harfbuzz/harfbuzz/issues/657 */ + if (unlikely (a > b || a == INVALID || b == INVALID)) return false; + dirty (); + unsigned int ma = get_major (a); + unsigned int mb = get_major (b); + if (ma == mb) + { + page_t *page = page_for (a, true); if (unlikely (!page)) return false; + page->add_range (a, b); + } + else + { + page_t *page = page_for (a, true); if (unlikely (!page)) return false; + page->add_range (a, major_start (ma + 1) - 1); + + for (unsigned int m = ma + 1; m < mb; m++) + { + page = page_for (major_start (m), true); if (unlikely (!page)) return false; + page->init1 (); + } + + page = page_for (b, true); if (unlikely (!page)) return false; + page->add_range (major_start (mb), b); + } + return true; + } + + /* Duplicated here from hb-machinery.hh to avoid including it. */ + template<typename Type> + static inline const Type& StructAtOffsetUnaligned(const void *P, unsigned int offset) + { +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wcast-align" + return * reinterpret_cast<const Type*> ((const char *) P + offset); +#pragma GCC diagnostic pop + } + + template <typename T> + void set_array (bool v, const T *array, unsigned int count, unsigned int stride=sizeof(T)) + { + if (unlikely (!successful)) return; + if (!count) return; + dirty (); + hb_codepoint_t g = *array; + while (count) + { + unsigned int m = get_major (g); + page_t *page = page_for (g, v); if (unlikely (v && !page)) return; + unsigned int start = major_start (m); + unsigned int end = major_start (m + 1); + do + { + if (g != INVALID && (v || page)) /* The v check is to optimize out the page check if v is true. */ + page->set (g, v); + + array = &StructAtOffsetUnaligned<T> (array, stride); + count--; + } + while (count && (g = *array, start <= g && g < end)); + } + } + + template <typename T> + void add_array (const T *array, unsigned int count, unsigned int stride=sizeof(T)) + { set_array (true, array, count, stride); } + template <typename T> + void add_array (const hb_array_t<const T>& arr) { add_array (&arr, arr.len ()); } + + template <typename T> + void del_array (const T *array, unsigned int count, unsigned int stride=sizeof(T)) + { set_array (false, array, count, stride); } + template <typename T> + void del_array (const hb_array_t<const T>& arr) { del_array (&arr, arr.len ()); } + + /* Might return false if array looks unsorted. + * Used for faster rejection of corrupt data. */ + template <typename T> + bool set_sorted_array (bool v, const T *array, unsigned int count, unsigned int stride=sizeof(T)) + { + if (unlikely (!successful)) return true; /* https://github.com/harfbuzz/harfbuzz/issues/657 */ + if (unlikely (!count)) return true; + dirty (); + hb_codepoint_t g = *array; + hb_codepoint_t last_g = g; + while (count) + { + unsigned int m = get_major (g); + page_t *page = page_for (g, v); if (unlikely (v && !page)) return false; + unsigned int end = major_start (m + 1); + do + { + /* If we try harder we can change the following comparison to <=; + * Not sure if it's worth it. */ + if (g < last_g) return false; + last_g = g; + + if (g != INVALID && (v || page)) /* The v check is to optimize out the page check if v is true. */ + page->add (g); + + array = &StructAtOffsetUnaligned<T> (array, stride); + count--; + } + while (count && (g = *array, g < end)); + } + return true; + } + + template <typename T> + bool add_sorted_array (const T *array, unsigned int count, unsigned int stride=sizeof(T)) + { return set_sorted_array (true, array, count, stride); } + template <typename T> + bool add_sorted_array (const hb_sorted_array_t<const T>& arr) { return add_sorted_array (&arr, arr.len ()); } + + template <typename T> + bool del_sorted_array (const T *array, unsigned int count, unsigned int stride=sizeof(T)) + { return set_sorted_array (false, array, count, stride); } + template <typename T> + bool del_sorted_array (const hb_sorted_array_t<const T>& arr) { return del_sorted_array (&arr, arr.len ()); } + + void del (hb_codepoint_t g) + { + if (unlikely (!successful)) return; + page_t *page = page_for (g); + if (!page) + return; + dirty (); + page->del (g); + } + + private: + void del_pages (int ds, int de) + { + if (ds <= de) + { + // Pre-allocate the workspace that compact() will need so we can bail on allocation failure + // before attempting to rewrite the page map. + hb_vector_t<unsigned> compact_workspace; + if (unlikely (!allocate_compact_workspace (compact_workspace))) return; + + unsigned int write_index = 0; + for (unsigned int i = 0; i < page_map.length; i++) + { + int m = (int) page_map[i].major; + if (m < ds || de < m) + page_map[write_index++] = page_map[i]; + } + compact (compact_workspace, write_index); + resize (write_index); + } + } + + + public: + void del_range (hb_codepoint_t a, hb_codepoint_t b) + { + if (unlikely (!successful)) return; + if (unlikely (a > b || a == INVALID)) return; + dirty (); + unsigned int ma = get_major (a); + unsigned int mb = get_major (b); + /* Delete pages from ds through de if ds <= de. */ + int ds = (a == major_start (ma))? (int) ma: (int) (ma + 1); + int de = (b + 1 == major_start (mb + 1))? (int) mb: ((int) mb - 1); + if (ds > de || (int) ma < ds) + { + page_t *page = page_for (a); + if (page) + { + if (ma == mb) + page->del_range (a, b); + else + page->del_range (a, major_start (ma + 1) - 1); + } + } + if (de < (int) mb && ma != mb) + { + page_t *page = page_for (b); + if (page) + page->del_range (major_start (mb), b); + } + del_pages (ds, de); + } + + bool get (hb_codepoint_t g) const + { + const page_t *page = page_for (g); + if (!page) + return false; + return page->get (g); + } + + /* Has interface. */ + bool operator [] (hb_codepoint_t k) const { return get (k); } + bool has (hb_codepoint_t k) const { return (*this)[k]; } + /* Predicate. */ + bool operator () (hb_codepoint_t k) const { return has (k); } + + /* Sink interface. */ + hb_bit_set_t& operator << (hb_codepoint_t v) + { add (v); return *this; } + hb_bit_set_t& operator << (const hb_codepoint_pair_t& range) + { add_range (range.first, range.second); return *this; } + + bool intersects (hb_codepoint_t first, hb_codepoint_t last) const + { + hb_codepoint_t c = first - 1; + return next (&c) && c <= last; + } + void set (const hb_bit_set_t &other, bool exact_size = false) + { + if (unlikely (!successful)) return; + unsigned int count = other.pages.length; + if (unlikely (!resize (count, false, exact_size))) + return; + population = other.population; + + page_map = other.page_map; + pages = other.pages; + } + + bool is_equal (const hb_bit_set_t &other) const + { + if (has_population () && other.has_population () && + population != other.population) + return false; + + unsigned int na = pages.length; + unsigned int nb = other.pages.length; + + unsigned int a = 0, b = 0; + for (; a < na && b < nb; ) + { + if (page_at (a).is_empty ()) { a++; continue; } + if (other.page_at (b).is_empty ()) { b++; continue; } + if (page_map[a].major != other.page_map[b].major || + !page_at (a).is_equal (other.page_at (b))) + return false; + a++; + b++; + } + for (; a < na; a++) + if (!page_at (a).is_empty ()) { return false; } + for (; b < nb; b++) + if (!other.page_at (b).is_empty ()) { return false; } + + return true; + } + + bool is_subset (const hb_bit_set_t &larger_set) const + { + if (has_population () && larger_set.has_population () && + population > larger_set.population) + return false; + + uint32_t spi = 0; + for (uint32_t lpi = 0; spi < page_map.length && lpi < larger_set.page_map.length; lpi++) + { + uint32_t spm = page_map[spi].major; + uint32_t lpm = larger_set.page_map[lpi].major; + auto sp = page_at (spi); + + if (spm < lpm && !sp.is_empty ()) + return false; + + if (lpm < spm) + continue; + + auto lp = larger_set.page_at (lpi); + if (!sp.is_subset (lp)) + return false; + + spi++; + } + + while (spi < page_map.length) + if (!page_at (spi++).is_empty ()) + return false; + + return true; + } + + private: + bool allocate_compact_workspace (hb_vector_t<unsigned>& workspace) + { + if (unlikely (!workspace.resize_exact (pages.length))) + { + successful = false; + return false; + } + + return true; + } + + /* + * workspace should be a pre-sized vector allocated to hold at exactly pages.length + * elements. + */ + void compact (hb_vector_t<unsigned>& workspace, + unsigned int length) + { + assert(workspace.length == pages.length); + hb_vector_t<unsigned>& old_index_to_page_map_index = workspace; + + hb_fill (old_index_to_page_map_index.writer(), 0xFFFFFFFF); + for (unsigned i = 0; i < length; i++) + old_index_to_page_map_index[page_map[i].index] = i; + + compact_pages (old_index_to_page_map_index); + } + void compact_pages (const hb_vector_t<unsigned>& old_index_to_page_map_index) + { + unsigned int write_index = 0; + for (unsigned int i = 0; i < pages.length; i++) + { + if (old_index_to_page_map_index[i] == 0xFFFFFFFF) continue; + + if (write_index < i) + pages[write_index] = pages[i]; + + page_map[old_index_to_page_map_index[i]].index = write_index; + write_index++; + } + } + public: + + void process_ (hb_bit_page_t::vector_t (*op) (const hb_bit_page_t::vector_t &, const hb_bit_page_t::vector_t &), + bool passthru_left, bool passthru_right, + const hb_bit_set_t &other) + { + if (unlikely (!successful)) return; + + dirty (); + + unsigned int na = pages.length; + unsigned int nb = other.pages.length; + unsigned int next_page = na; + + unsigned int count = 0, newCount = 0; + unsigned int a = 0, b = 0; + unsigned int write_index = 0; + + // Pre-allocate the workspace that compact() will need so we can bail on allocation failure + // before attempting to rewrite the page map. + hb_vector_t<unsigned> compact_workspace; + if (!passthru_left && unlikely (!allocate_compact_workspace (compact_workspace))) return; + + for (; a < na && b < nb; ) + { + if (page_map[a].major == other.page_map[b].major) + { + if (!passthru_left) + { + // Move page_map entries that we're keeping from the left side set + // to the front of the page_map vector. This isn't necessary if + // passthru_left is set since no left side pages will be removed + // in that case. + if (write_index < a) + page_map[write_index] = page_map[a]; + write_index++; + } + + count++; + a++; + b++; + } + else if (page_map[a].major < other.page_map[b].major) + { + if (passthru_left) + count++; + a++; + } + else + { + if (passthru_right) + count++; + b++; + } + } + if (passthru_left) + count += na - a; + if (passthru_right) + count += nb - b; + + if (!passthru_left) + { + na = write_index; + next_page = write_index; + compact (compact_workspace, write_index); + } + + if (unlikely (!resize (count))) + return; + + newCount = count; + + /* Process in-place backward. */ + a = na; + b = nb; + for (; a && b; ) + { + if (page_map.arrayZ[a - 1].major == other.page_map.arrayZ[b - 1].major) + { + a--; + b--; + count--; + page_map.arrayZ[count] = page_map.arrayZ[a]; + page_at (count).v = op (page_at (a).v, other.page_at (b).v); + page_at (count).dirty (); + } + else if (page_map.arrayZ[a - 1].major > other.page_map.arrayZ[b - 1].major) + { + a--; + if (passthru_left) + { + count--; + page_map.arrayZ[count] = page_map.arrayZ[a]; + } + } + else + { + b--; + if (passthru_right) + { + count--; + page_map.arrayZ[count].major = other.page_map.arrayZ[b].major; + page_map.arrayZ[count].index = next_page++; + page_at (count) = other.page_at (b); + } + } + } + if (passthru_left) + while (a) + { + a--; + count--; + page_map.arrayZ[count] = page_map.arrayZ[a]; + } + if (passthru_right) + while (b) + { + b--; + count--; + page_map.arrayZ[count].major = other.page_map.arrayZ[b].major; + page_map.arrayZ[count].index = next_page++; + page_at (count) = other.page_at (b); + } + assert (!count); + resize (newCount); + } + template <typename Op> + static hb_bit_page_t::vector_t + op_ (const hb_bit_page_t::vector_t &a, const hb_bit_page_t::vector_t &b) + { return Op{} (a, b); } + template <typename Op> + void process (const Op& op, const hb_bit_set_t &other) + { + process_ (op_<Op>, op (1, 0), op (0, 1), other); + } + + void union_ (const hb_bit_set_t &other) { process (hb_bitwise_or, other); } + void intersect (const hb_bit_set_t &other) { process (hb_bitwise_and, other); } + void subtract (const hb_bit_set_t &other) { process (hb_bitwise_gt, other); } + void symmetric_difference (const hb_bit_set_t &other) { process (hb_bitwise_xor, other); } + + bool next (hb_codepoint_t *codepoint) const + { + if (unlikely (*codepoint == INVALID)) { + *codepoint = get_min (); + return *codepoint != INVALID; + } + + const auto* page_map_array = page_map.arrayZ; + unsigned int major = get_major (*codepoint); + unsigned int i = last_page_lookup; + + if (unlikely (i >= page_map.length || page_map_array[i].major != major)) + { + page_map.bfind (major, &i, HB_NOT_FOUND_STORE_CLOSEST); + if (i >= page_map.length) { + *codepoint = INVALID; + return false; + } + last_page_lookup = i; + } + + const auto* pages_array = pages.arrayZ; + const page_map_t ¤t = page_map_array[i]; + if (likely (current.major == major)) + { + if (pages_array[current.index].next (codepoint)) + { + *codepoint += current.major * page_t::PAGE_BITS; + return true; + } + i++; + } + + for (; i < page_map.length; i++) + { + const page_map_t ¤t = page_map_array[i]; + hb_codepoint_t m = pages_array[current.index].get_min (); + if (m != INVALID) + { + *codepoint = current.major * page_t::PAGE_BITS + m; + last_page_lookup = i; + return true; + } + } + *codepoint = INVALID; + return false; + } + bool previous (hb_codepoint_t *codepoint) const + { + if (unlikely (*codepoint == INVALID)) { + *codepoint = get_max (); + return *codepoint != INVALID; + } + + page_map_t map = {get_major (*codepoint), 0}; + unsigned int i; + page_map.bfind (map, &i, HB_NOT_FOUND_STORE_CLOSEST); + if (i < page_map.length && page_map.arrayZ[i].major == map.major) + { + if (pages[page_map.arrayZ[i].index].previous (codepoint)) + { + *codepoint += page_map.arrayZ[i].major * page_t::PAGE_BITS; + return true; + } + } + i--; + for (; (int) i >= 0; i--) + { + hb_codepoint_t m = pages.arrayZ[page_map.arrayZ[i].index].get_max (); + if (m != INVALID) + { + *codepoint = page_map.arrayZ[i].major * page_t::PAGE_BITS + m; + return true; + } + } + *codepoint = INVALID; + return false; + } + bool next_range (hb_codepoint_t *first, hb_codepoint_t *last) const + { + hb_codepoint_t i; + + i = *last; + if (!next (&i)) + { + *last = *first = INVALID; + return false; + } + + /* TODO Speed up. */ + *last = *first = i; + while (next (&i) && i == *last + 1) + (*last)++; + + return true; + } + bool previous_range (hb_codepoint_t *first, hb_codepoint_t *last) const + { + hb_codepoint_t i; + + i = *first; + if (!previous (&i)) + { + *last = *first = INVALID; + return false; + } + + /* TODO Speed up. */ + *last = *first = i; + while (previous (&i) && i == *first - 1) + (*first)--; + + return true; + } + + unsigned int next_many (hb_codepoint_t codepoint, + hb_codepoint_t *out, + unsigned int size) const + { + // By default, start at the first bit of the first page of values. + unsigned int start_page = 0; + unsigned int start_page_value = 0; + if (unlikely (codepoint != INVALID)) + { + const auto* page_map_array = page_map.arrayZ; + unsigned int major = get_major (codepoint); + unsigned int i = last_page_lookup; + if (unlikely (i >= page_map.length || page_map_array[i].major != major)) + { + page_map.bfind (major, &i, HB_NOT_FOUND_STORE_CLOSEST); + if (i >= page_map.length) + return 0; // codepoint is greater than our max element. + } + start_page = i; + start_page_value = page_remainder (codepoint + 1); + if (unlikely (start_page_value == 0)) + { + // The export-after value was last in the page. Start on next page. + start_page++; + start_page_value = 0; + } + } + + unsigned int initial_size = size; + for (unsigned int i = start_page; i < page_map.length && size; i++) + { + uint32_t base = major_start (page_map[i].major); + unsigned int n = pages[page_map[i].index].write (base, start_page_value, out, size); + out += n; + size -= n; + start_page_value = 0; + } + return initial_size - size; + } + + unsigned int next_many_inverted (hb_codepoint_t codepoint, + hb_codepoint_t *out, + unsigned int size) const + { + unsigned int initial_size = size; + // By default, start at the first bit of the first page of values. + unsigned int start_page = 0; + unsigned int start_page_value = 0; + if (unlikely (codepoint != INVALID)) + { + const auto* page_map_array = page_map.arrayZ; + unsigned int major = get_major (codepoint); + unsigned int i = last_page_lookup; + if (unlikely (i >= page_map.length || page_map_array[i].major != major)) + { + page_map.bfind(major, &i, HB_NOT_FOUND_STORE_CLOSEST); + if (unlikely (i >= page_map.length)) + { + // codepoint is greater than our max element. + while (++codepoint != INVALID && size) + { + *out++ = codepoint; + size--; + } + return initial_size - size; + } + } + start_page = i; + start_page_value = page_remainder (codepoint + 1); + if (unlikely (start_page_value == 0)) + { + // The export-after value was last in the page. Start on next page. + start_page++; + start_page_value = 0; + } + } + + hb_codepoint_t next_value = codepoint + 1; + for (unsigned int i=start_page; i<page_map.length && size; i++) + { + uint32_t base = major_start (page_map[i].major); + unsigned int n = pages[page_map[i].index].write_inverted (base, start_page_value, out, size, &next_value); + out += n; + size -= n; + start_page_value = 0; + } + while (next_value < HB_SET_VALUE_INVALID && size) { + *out++ = next_value++; + size--; + } + return initial_size - size; + } + + bool has_population () const { return population != UINT_MAX; } + unsigned int get_population () const + { + if (has_population ()) + return population; + + unsigned int pop = 0; + unsigned int count = pages.length; + for (unsigned int i = 0; i < count; i++) + pop += pages[i].get_population (); + + population = pop; + return pop; + } + hb_codepoint_t get_min () const + { + unsigned count = pages.length; + for (unsigned i = 0; i < count; i++) + { + const auto& map = page_map[i]; + const auto& page = pages[map.index]; + + if (!page.is_empty ()) + return map.major * page_t::PAGE_BITS + page.get_min (); + } + return INVALID; + } + hb_codepoint_t get_max () const + { + unsigned count = pages.length; + for (signed i = count - 1; i >= 0; i--) + { + const auto& map = page_map[(unsigned) i]; + const auto& page = pages[map.index]; + + if (!page.is_empty ()) + return map.major * page_t::PAGE_BITS + page.get_max (); + } + return INVALID; + } + + static constexpr hb_codepoint_t INVALID = page_t::INVALID; + + /* + * Iterator implementation. + */ + struct iter_t : hb_iter_with_fallback_t<iter_t, hb_codepoint_t> + { + static constexpr bool is_sorted_iterator = true; + static constexpr bool has_fast_len = true; + iter_t (const hb_bit_set_t &s_ = Null (hb_bit_set_t), + bool init = true) : s (&s_), v (INVALID), l(0) + { + if (init) + { + l = s->get_population () + 1; + __next__ (); + } + } + + typedef hb_codepoint_t __item_t__; + hb_codepoint_t __item__ () const { return v; } + bool __more__ () const { return v != INVALID; } + void __next__ () { s->next (&v); if (l) l--; } + void __prev__ () { s->previous (&v); } + unsigned __len__ () const { return l; } + iter_t end () const { return iter_t (*s, false); } + bool operator != (const iter_t& o) const + { return s != o.s || v != o.v; } + + protected: + const hb_bit_set_t *s; + hb_codepoint_t v; + unsigned l; + }; + iter_t iter () const { return iter_t (*this); } + operator iter_t () const { return iter (); } + + protected: + + page_t *page_for (hb_codepoint_t g, bool insert = false) + { + unsigned major = get_major (g); + + /* The extra page_map length is necessary; can't just rely on vector here, + * since the next check would be tricked because a null page also has + * major==0, which we can't distinguish from an actually major==0 page... */ + unsigned i = last_page_lookup; + if (likely (i < page_map.length)) + { + auto &cached_page = page_map.arrayZ[i]; + if (cached_page.major == major) + return &pages.arrayZ[cached_page.index]; + } + + page_map_t map = {major, pages.length}; + if (!page_map.bfind (map, &i, HB_NOT_FOUND_STORE_CLOSEST)) + { + if (!insert) + return nullptr; + + if (unlikely (!resize (pages.length + 1))) + return nullptr; + + pages.arrayZ[map.index].init0 (); + memmove (page_map.arrayZ + i + 1, + page_map.arrayZ + i, + (page_map.length - 1 - i) * page_map.item_size); + page_map.arrayZ[i] = map; + } + + last_page_lookup = i; + return &pages.arrayZ[page_map.arrayZ[i].index]; + } + const page_t *page_for (hb_codepoint_t g) const + { + unsigned major = get_major (g); + + /* The extra page_map length is necessary; can't just rely on vector here, + * since the next check would be tricked because a null page also has + * major==0, which we can't distinguish from an actually major==0 page... */ + unsigned i = last_page_lookup; + if (likely (i < page_map.length)) + { + auto &cached_page = page_map.arrayZ[i]; + if (cached_page.major == major) + return &pages.arrayZ[cached_page.index]; + } + + page_map_t key = {major}; + if (!page_map.bfind (key, &i)) + return nullptr; + + last_page_lookup = i; + return &pages.arrayZ[page_map[i].index]; + } + page_t &page_at (unsigned int i) + { + assert (i < page_map.length); + return pages.arrayZ[page_map.arrayZ[i].index]; + } + const page_t &page_at (unsigned int i) const + { + assert (i < page_map.length); + return pages.arrayZ[page_map.arrayZ[i].index]; + } + unsigned int get_major (hb_codepoint_t g) const { return g >> page_t::PAGE_BITS_LOG_2; } + unsigned int page_remainder (hb_codepoint_t g) const { return g & page_t::PAGE_BITMASK; } + hb_codepoint_t major_start (unsigned int major) const { return major << page_t::PAGE_BITS_LOG_2; } +}; + + +#endif /* HB_BIT_SET_HH */ |