331 lines
9.3 KiB
C++
331 lines
9.3 KiB
C++
/*
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* Copyright © 2012,2017 Google, Inc.
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* Copyright © 2021 Behdad Esfahbod
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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_BIT_PAGE_HH
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#define HB_BIT_PAGE_HH
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#include "hb.hh"
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/* Compiler-assisted vectorization. */
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/* Type behaving similar to vectorized vars defined using __attribute__((vector_size(...))),
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* basically a fixed-size bitset. */
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template <typename elt_t, unsigned int byte_size>
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struct hb_vector_size_t
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{
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elt_t& operator [] (unsigned int i) { return v[i]; }
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const elt_t& operator [] (unsigned int i) const { return v[i]; }
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void clear (unsigned char v = 0) { hb_memset (this, v, sizeof (*this)); }
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template <typename Op>
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hb_vector_size_t process (const Op& op) const
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{
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hb_vector_size_t r;
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for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
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r.v[i] = op (v[i]);
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return r;
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}
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template <typename Op>
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hb_vector_size_t process (const Op& op, const hb_vector_size_t &o) const
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{
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hb_vector_size_t r;
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for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
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r.v[i] = op (v[i], o.v[i]);
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return r;
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}
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hb_vector_size_t operator | (const hb_vector_size_t &o) const
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{ return process (hb_bitwise_or, o); }
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hb_vector_size_t operator & (const hb_vector_size_t &o) const
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{ return process (hb_bitwise_and, o); }
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hb_vector_size_t operator ^ (const hb_vector_size_t &o) const
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{ return process (hb_bitwise_xor, o); }
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hb_vector_size_t operator ~ () const
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{ return process (hb_bitwise_neg); }
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hb_array_t<const elt_t> iter () const
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{ return hb_array (v); }
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private:
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static_assert (0 == byte_size % sizeof (elt_t), "");
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elt_t v[byte_size / sizeof (elt_t)];
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};
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struct hb_bit_page_t
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{
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void init0 () { v.clear (); }
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void init1 () { v.clear (0xFF); }
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constexpr unsigned len () const
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{ return ARRAY_LENGTH_CONST (v); }
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bool is_empty () const
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{
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return
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+ hb_iter (v)
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| hb_none
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;
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}
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uint32_t hash () const
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{
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return
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+ hb_iter (v)
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| hb_reduce ([] (uint32_t h, const elt_t &_) { return h * 31 + hb_hash (_); }, (uint32_t) 0u)
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;
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}
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void add (hb_codepoint_t g) { elt (g) |= mask (g); }
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void del (hb_codepoint_t g) { elt (g) &= ~mask (g); }
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void set (hb_codepoint_t g, bool value) { if (value) add (g); else del (g); }
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bool get (hb_codepoint_t g) const { return elt (g) & mask (g); }
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void add_range (hb_codepoint_t a, hb_codepoint_t b)
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{
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elt_t *la = &elt (a);
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elt_t *lb = &elt (b);
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if (la == lb)
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*la |= (mask (b) << 1) - mask(a);
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else
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{
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*la |= ~(mask (a) - 1);
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la++;
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hb_memset (la, 0xff, (char *) lb - (char *) la);
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*lb |= ((mask (b) << 1) - 1);
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}
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}
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void del_range (hb_codepoint_t a, hb_codepoint_t b)
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{
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elt_t *la = &elt (a);
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elt_t *lb = &elt (b);
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if (la == lb)
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*la &= ~((mask (b) << 1) - mask(a));
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else
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{
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*la &= mask (a) - 1;
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la++;
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hb_memset (la, 0, (char *) lb - (char *) la);
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*lb &= ~((mask (b) << 1) - 1);
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}
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}
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void set_range (hb_codepoint_t a, hb_codepoint_t b, bool v)
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{ if (v) add_range (a, b); else del_range (a, b); }
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// Writes out page values to the array p. Returns the number of values
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// written. At most size codepoints will be written.
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unsigned int write (uint32_t base,
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unsigned int start_value,
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hb_codepoint_t *p,
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unsigned int size) const
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{
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unsigned int start_v = start_value / ELT_BITS;
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unsigned int start_bit = start_value & ELT_MASK;
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unsigned int count = 0;
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for (unsigned i = start_v; i < len () && count < size; i++)
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{
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elt_t bits = v[i];
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uint32_t v_base = base | (i * ELT_BITS);
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for (unsigned int j = start_bit; j < ELT_BITS && count < size; j++)
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{
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if ((elt_t(1) << j) & bits) {
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*p++ = v_base | j;
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count++;
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}
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}
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start_bit = 0;
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}
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return count;
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}
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// Writes out the values NOT in this page to the array p. Returns the
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// number of values written. At most size codepoints will be written.
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// Returns the number of codepoints written. next_value holds the next value
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// that should be written (if not present in this page). This is used to fill
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// any missing value gaps between this page and the previous page, if any.
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// next_value is updated to one more than the last value present in this page.
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unsigned int write_inverted (uint32_t base,
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unsigned int start_value,
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hb_codepoint_t *p,
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unsigned int size,
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hb_codepoint_t *next_value) const
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{
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unsigned int start_v = start_value / ELT_BITS;
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unsigned int start_bit = start_value & ELT_MASK;
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unsigned int count = 0;
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for (unsigned i = start_v; i < len () && count < size; i++)
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{
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elt_t bits = v[i];
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uint32_t v_offset = i * ELT_BITS;
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for (unsigned int j = start_bit; j < ELT_BITS && count < size; j++)
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{
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if ((elt_t(1) << j) & bits)
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{
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hb_codepoint_t value = base | v_offset | j;
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// Emit all the missing values from next_value up to value - 1.
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for (hb_codepoint_t k = *next_value; k < value && count < size; k++)
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{
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*p++ = k;
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count++;
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}
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// Skip over this value;
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*next_value = value + 1;
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}
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}
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start_bit = 0;
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}
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return count;
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}
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bool is_equal (const hb_bit_page_t &other) const
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{
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for (unsigned i = 0; i < len (); i++)
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if (v[i] != other.v[i])
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return false;
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return true;
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}
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bool is_subset (const hb_bit_page_t &larger_page) const
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{
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for (unsigned i = 0; i < len (); i++)
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if (~larger_page.v[i] & v[i])
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return false;
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return true;
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}
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unsigned int get_population () const
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{
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return
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+ hb_iter (v)
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| hb_reduce ([] (unsigned pop, const elt_t &_) { return pop + hb_popcount (_); }, 0u)
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;
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}
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bool next (hb_codepoint_t *codepoint) const
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{
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unsigned int m = (*codepoint + 1) & MASK;
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if (!m)
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{
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*codepoint = INVALID;
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return false;
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}
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unsigned int i = m / ELT_BITS;
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unsigned int j = m & ELT_MASK;
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const elt_t vv = v[i] & ~((elt_t (1) << j) - 1);
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for (const elt_t *p = &vv; i < len (); p = &v[++i])
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if (*p)
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{
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*codepoint = i * ELT_BITS + elt_get_min (*p);
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return true;
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}
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*codepoint = INVALID;
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return false;
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}
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bool previous (hb_codepoint_t *codepoint) const
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{
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unsigned int m = (*codepoint - 1) & MASK;
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if (m == MASK)
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{
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*codepoint = INVALID;
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return false;
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}
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unsigned int i = m / ELT_BITS;
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unsigned int j = m & ELT_MASK;
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/* Fancy mask to avoid shifting by elt_t bitsize, which is undefined. */
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const elt_t mask = j < 8 * sizeof (elt_t) - 1 ?
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((elt_t (1) << (j + 1)) - 1) :
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(elt_t) -1;
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const elt_t vv = v[i] & mask;
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const elt_t *p = &vv;
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while (true)
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{
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if (*p)
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{
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*codepoint = i * ELT_BITS + elt_get_max (*p);
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return true;
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}
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if ((int) i <= 0) break;
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p = &v[--i];
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}
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*codepoint = INVALID;
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return false;
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}
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hb_codepoint_t get_min () const
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{
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for (unsigned int i = 0; i < len (); i++)
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if (v[i])
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return i * ELT_BITS + elt_get_min (v[i]);
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return INVALID;
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}
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hb_codepoint_t get_max () const
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{
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for (int i = len () - 1; i >= 0; i--)
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if (v[i])
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return i * ELT_BITS + elt_get_max (v[i]);
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return 0;
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}
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static constexpr hb_codepoint_t INVALID = HB_SET_VALUE_INVALID;
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typedef unsigned long long elt_t;
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static constexpr unsigned PAGE_BITS = 512;
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static_assert ((PAGE_BITS & ((PAGE_BITS) - 1)) == 0, "");
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static constexpr unsigned PAGE_BITS_LOG_2 = 9;
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static_assert (1 << PAGE_BITS_LOG_2 == PAGE_BITS, "");
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static constexpr unsigned PAGE_BITMASK = PAGE_BITS - 1;
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static unsigned int elt_get_min (const elt_t &elt) { return hb_ctz (elt); }
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static unsigned int elt_get_max (const elt_t &elt) { return hb_bit_storage (elt) - 1; }
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typedef hb_vector_size_t<elt_t, PAGE_BITS / 8> vector_t;
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static constexpr unsigned ELT_BITS = sizeof (elt_t) * 8;
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static constexpr unsigned ELT_MASK = ELT_BITS - 1;
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static constexpr unsigned BITS = sizeof (vector_t) * 8;
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static constexpr unsigned MASK = BITS - 1;
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static_assert ((unsigned) PAGE_BITS == (unsigned) BITS, "");
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elt_t &elt (hb_codepoint_t g) { return v[(g & MASK) / ELT_BITS]; }
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const elt_t& elt (hb_codepoint_t g) const { return v[(g & MASK) / ELT_BITS]; }
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static constexpr elt_t mask (hb_codepoint_t g) { return elt_t (1) << (g & ELT_MASK); }
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vector_t v;
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};
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static_assert (hb_bit_page_t::PAGE_BITS == sizeof (hb_bit_page_t) * 8, "");
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#endif /* HB_BIT_PAGE_HH */
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