Behdad Esfahbod
4 years ago
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0c3e02ee2d
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9b390f8c40
4 changed files with 221 additions and 183 deletions
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/*
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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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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 (bool inverted = false) const |
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{ |
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for (unsigned int i = 0; i < len (); i++) |
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if (elt_maybe_invert (v[i], inverted)) |
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return false; |
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return true; |
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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 v) { if (v) 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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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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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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bool is_equal (const hb_bit_page_t &other) const |
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{ |
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return 0 == hb_memcmp (&v, &other.v, sizeof (v)); |
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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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unsigned int pop = 0; |
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for (unsigned int i = 0; i < len (); i++) |
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pop += hb_popcount (v[i]); |
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return pop; |
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} |
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bool next (hb_codepoint_t *codepoint, bool inverted = false) 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 (elt_t p = elt_maybe_invert (vv, inverted); |
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i < len (); |
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p = elt_maybe_invert (v[++i], inverted)) |
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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, bool inverted = false) 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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elt_t p = elt_maybe_invert (vv, inverted); |
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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 = elt_maybe_invert (v[--i], inverted); |
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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 (bool inverted = false) const |
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{ |
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for (unsigned int i = 0; i < len (); i++) |
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{ |
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elt_t e = elt_maybe_invert (v[i], inverted); |
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if (e) |
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return i * ELT_BITS + elt_get_min (e); |
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} |
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return INVALID; |
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} |
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hb_codepoint_t get_max (bool inverted = false) const |
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{ |
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for (int i = len () - 1; i >= 0; i--) |
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{ |
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elt_t e = elt_maybe_invert (v[i], inverted); |
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if (e) |
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return i * ELT_BITS + elt_get_max (e); |
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} |
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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 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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static elt_t elt_maybe_invert (elt_t elt, bool inverted) { return inverted ? ~elt : elt; } |
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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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