Path: blob/master/thirdparty/harfbuzz/src/hb-bit-page.hh
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/*
* 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_PAGE_HH
#define HB_BIT_PAGE_HH
#include "hb.hh"
/* Compiler-assisted vectorization. */
/* Type behaving similar to vectorized vars defined using __attribute__((vector_size(...))),
* basically a fixed-size bitset. We can't use the compiler type because hb_vector_t cannot
* guarantee alignment requirements. */
template <typename elt_t, unsigned int byte_size>
struct hb_vector_size_t
{
elt_t& operator [] (unsigned int i) { return v[i]; }
const elt_t& operator [] (unsigned int i) const { return v[i]; }
void init0 ()
{
for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
v[i] = 0;
}
void init1 ()
{
for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
v[i] = (elt_t) -1;
}
template <typename Op>
hb_vector_size_t process (const Op& op) const
{
hb_vector_size_t r;
for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
r.v[i] = op (v[i]);
return r;
}
template <typename Op>
hb_vector_size_t process (const Op& op, const hb_vector_size_t &o) const
{
hb_vector_size_t r;
for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
r.v[i] = op (v[i], o.v[i]);
return r;
}
hb_vector_size_t operator | (const hb_vector_size_t &o) const
{ return process (hb_bitwise_or, o); }
hb_vector_size_t operator & (const hb_vector_size_t &o) const
{ return process (hb_bitwise_and, o); }
hb_vector_size_t operator ^ (const hb_vector_size_t &o) const
{ return process (hb_bitwise_xor, o); }
hb_vector_size_t operator ~ () const
{ return process (hb_bitwise_neg); }
operator bool () const
{
for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
if (v[i])
return true;
return false;
}
operator unsigned int () const
{
unsigned int r = 0;
for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
r += hb_popcount (v[i]);
return r;
}
bool operator == (const hb_vector_size_t &o) const
{
for (unsigned int i = 0; i < ARRAY_LENGTH (v); i++)
if (v[i] != o.v[i])
return false;
return true;
}
hb_array_t<const elt_t> iter () const
{ return hb_array (v); }
private:
static_assert (0 == byte_size % sizeof (elt_t), "");
elt_t v[byte_size / sizeof (elt_t)];
};
struct hb_bit_page_t
{
hb_bit_page_t () { init0 (); }
void init0 () { v.init0 (); population = 0; }
void init1 () { v.init1 (); population = PAGE_BITS; }
void dirty () { population = UINT_MAX; }
static inline constexpr unsigned len ()
{ return ARRAY_LENGTH_CONST (v); }
operator bool () const { return !is_empty (); }
bool is_empty () const
{
if (has_population ()) return !population;
bool empty = !v;
if (empty) population = 0;
return empty;
}
uint32_t hash () const
{
return hb_bytes_t ((const char *) &v, sizeof (v)).hash ();
}
void add (hb_codepoint_t g) { elt (g) |= mask (g); dirty (); }
void del (hb_codepoint_t g) { elt (g) &= ~mask (g); dirty (); }
void set (hb_codepoint_t g, bool value) { if (value) add (g); else del (g); }
bool get (hb_codepoint_t g) const { return elt (g) & mask (g); }
bool may_have (hb_codepoint_t g) const { return get (g); }
bool operator [] (hb_codepoint_t g) const { return get (g); }
bool operator () (hb_codepoint_t g) const { return get (g); }
void add_range (hb_codepoint_t a, hb_codepoint_t b)
{
elt_t *la = &elt (a);
elt_t *lb = &elt (b);
if (la == lb)
*la |= (mask (b) << 1) - mask(a);
else
{
*la |= ~(mask (a) - 1llu);
la++;
hb_memset (la, 0xff, (char *) lb - (char *) la);
*lb |= ((mask (b) << 1) - 1llu);
}
dirty ();
}
void del_range (hb_codepoint_t a, hb_codepoint_t b)
{
elt_t *la = &elt (a);
elt_t *lb = &elt (b);
if (la == lb)
*la &= ~((mask (b) << 1llu) - mask(a));
else
{
*la &= mask (a) - 1;
la++;
hb_memset (la, 0, (char *) lb - (char *) la);
*lb &= ~((mask (b) << 1) - 1llu);
}
dirty ();
}
void set_range (hb_codepoint_t a, hb_codepoint_t b, bool v)
{ if (v) add_range (a, b); else del_range (a, b); }
// Writes out page values to the array p. Returns the number of values
// written. At most size codepoints will be written.
unsigned int write (uint32_t base,
unsigned int start_value,
hb_codepoint_t *p,
unsigned int size) const
{
unsigned int start_v = start_value / ELT_BITS;
unsigned int start_bit = start_value & ELT_MASK;
unsigned int count = 0;
for (unsigned i = start_v; i < len () && count < size; i++)
{
elt_t bits = v[i];
uint32_t v_base = base | (i * ELT_BITS);
for (unsigned int j = start_bit; j < ELT_BITS && count < size; j++)
{
if ((elt_t(1) << j) & bits) {
*p++ = v_base | j;
count++;
}
}
start_bit = 0;
}
return count;
}
// Writes out the values NOT in this page to the array p. Returns the
// number of values written. At most size codepoints will be written.
// Returns the number of codepoints written. next_value holds the next value
// that should be written (if not present in this page). This is used to fill
// any missing value gaps between this page and the previous page, if any.
// next_value is updated to one more than the last value present in this page.
unsigned int write_inverted (uint32_t base,
unsigned int start_value,
hb_codepoint_t *p,
unsigned int size,
hb_codepoint_t *next_value) const
{
unsigned int start_v = start_value / ELT_BITS;
unsigned int start_bit = start_value & ELT_MASK;
unsigned int count = 0;
for (unsigned i = start_v; i < len () && count < size; i++)
{
elt_t bits = v[i];
uint32_t v_offset = i * ELT_BITS;
for (unsigned int j = start_bit; j < ELT_BITS && count < size; j++)
{
if ((elt_t(1) << j) & bits)
{
hb_codepoint_t value = base | v_offset | j;
// Emit all the missing values from next_value up to value - 1.
for (hb_codepoint_t k = *next_value; k < value && count < size; k++)
{
*p++ = k;
count++;
}
// Skip over this value;
*next_value = value + 1;
}
}
start_bit = 0;
}
return count;
}
bool operator == (const hb_bit_page_t &other) const { return is_equal (other); }
bool is_equal (const hb_bit_page_t &other) const { return v == other.v; }
bool intersects (const hb_bit_page_t &other) const
{
for (unsigned i = 0; i < len (); i++)
if (v[i] & other.v[i])
return true;
return false;
}
bool may_intersect (const hb_bit_page_t &other) const
{ return intersects (other); }
bool operator <= (const hb_bit_page_t &larger_page) const { return is_subset (larger_page); }
bool is_subset (const hb_bit_page_t &larger_page) const
{
if (has_population () && larger_page.has_population () &&
population > larger_page.population)
return false;
for (unsigned i = 0; i < len (); i++)
if (~larger_page.v[i] & v[i])
return false;
return true;
}
bool has_population () const { return population != UINT_MAX; }
unsigned get_population () const
{
if (has_population ()) return population;
return population = v;
}
bool next (hb_codepoint_t *codepoint) const
{
unsigned int m = (*codepoint + 1) & MASK;
if (!m)
{
*codepoint = INVALID;
return false;
}
unsigned int i = m / ELT_BITS;
unsigned int j = m & ELT_MASK;
const elt_t vv = v[i] & ~((elt_t (1) << j) - 1);
for (const elt_t *p = &vv; i < len (); p = &v[++i])
if (*p)
{
*codepoint = i * ELT_BITS + elt_get_min (*p);
return true;
}
*codepoint = INVALID;
return false;
}
bool previous (hb_codepoint_t *codepoint) const
{
unsigned int m = (*codepoint - 1) & MASK;
if (m == MASK)
{
*codepoint = INVALID;
return false;
}
unsigned int i = m / ELT_BITS;
unsigned int j = m & ELT_MASK;
/* Fancy mask to avoid shifting by elt_t bitsize, which is undefined. */
const elt_t mask = j < 8 * sizeof (elt_t) - 1 ?
((elt_t (1) << (j + 1)) - 1) :
(elt_t) -1;
const elt_t vv = v[i] & mask;
const elt_t *p = &vv;
while (true)
{
if (*p)
{
*codepoint = i * ELT_BITS + elt_get_max (*p);
return true;
}
if ((int) i <= 0) break;
p = &v[--i];
}
*codepoint = INVALID;
return false;
}
hb_codepoint_t get_min () const
{
for (unsigned int i = 0; i < len (); i++)
if (v[i])
return i * ELT_BITS + elt_get_min (v[i]);
return INVALID;
}
hb_codepoint_t get_max () const
{
for (int i = len () - 1; i >= 0; i--)
if (v[i])
return i * ELT_BITS + elt_get_max (v[i]);
return 0;
}
static constexpr hb_codepoint_t INVALID = HB_SET_VALUE_INVALID;
typedef unsigned long long elt_t;
static constexpr unsigned PAGE_BITS_LOG_2 = 9; // 512 bits
static constexpr unsigned PAGE_BITS = 1 << PAGE_BITS_LOG_2;
static_assert (1 << PAGE_BITS_LOG_2 == PAGE_BITS, "");
static_assert ((PAGE_BITS & ((PAGE_BITS) - 1)) == 0, "");
static constexpr unsigned PAGE_BITMASK = PAGE_BITS - 1;
static unsigned int elt_get_min (const elt_t &elt) { return hb_ctz (elt); }
static unsigned int elt_get_max (const elt_t &elt) { return hb_bit_storage (elt) - 1; }
typedef hb_vector_size_t<elt_t, PAGE_BITS / 8> vector_t;
static constexpr unsigned ELT_BITS = sizeof (elt_t) * 8;
static constexpr unsigned ELT_MASK = ELT_BITS - 1;
static constexpr unsigned BITS = sizeof (vector_t) * 8;
static constexpr unsigned MASK = BITS - 1;
static_assert ((unsigned) PAGE_BITS == (unsigned) BITS, "");
elt_t &elt (hb_codepoint_t g) { return v[(g & MASK) / ELT_BITS]; }
const elt_t& elt (hb_codepoint_t g) const { return v[(g & MASK) / ELT_BITS]; }
static constexpr elt_t mask (hb_codepoint_t g) { return elt_t (1) << (g & ELT_MASK); }
mutable unsigned population;
vector_t v;
};
#endif /* HB_BIT_PAGE_HH */