src/hb-set-private.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2012  Google, Inc.
  *
  *  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_SET_PRIVATE_HH
 #define HB_SET_PRIVATE_HH

 #include "hb-private.hh"
 #include "hb-set.h"
 #include "hb-object-private.hh"


 /*
  * The set digests here implement various "filters" that support
  * "approximate member query".  Conceptually these are like Bloom
  * Filter and Quotient Filter, however, much smaller, faster, and
  * designed to fit the requirements of our uses for glyph coverage
  * queries.  As a result, our filters have much higher.
  */

 template <typename mask_t, unsigned int shift>
 struct hb_set_digest_lowest_bits_t
 {
   ASSERT_POD ();

   static const unsigned int mask_bytes = sizeof (mask_t);
   static const unsigned int mask_bits = sizeof (mask_t) * 8;
   static const unsigned int num_bits = 0
 				     + (mask_bytes >= 1 ? 3 : 0)
 				     + (mask_bytes >= 2 ? 1 : 0)
 				     + (mask_bytes >= 4 ? 1 : 0)
 				     + (mask_bytes >= 8 ? 1 : 0)
 				     + (mask_bytes >= 16? 1 : 0)
 				     + 0;

   ASSERT_STATIC (shift < sizeof (hb_codepoint_t) * 8);
   ASSERT_STATIC (shift + num_bits <= sizeof (hb_codepoint_t) * 8);

   inline void init (void) {
     mask = 0;
   }

   inline void add (hb_codepoint_t g) {
     mask |= mask_for (g);
   }

   inline void add_range (hb_codepoint_t a, hb_codepoint_t b) {
     if ((b >> shift) - (a >> shift) >= mask_bits - 1)
       mask = (mask_t) -1;
     else {
       mask_t ma = mask_for (a);
       mask_t mb = mask_for (b);
       mask |= mb + (mb - ma) - (mb < ma);
     }
   }

   inline bool may_have (hb_codepoint_t g) const {
     return !!(mask & mask_for (g));
   }

   private:

   static inline mask_t mask_for (hb_codepoint_t g) {
     return ((mask_t) 1) << ((g >> shift) & (mask_bits - 1));
   }
   mask_t mask;
 };

 template <typename head_t, typename tail_t>
 struct hb_set_digest_combiner_t
 {
   ASSERT_POD ();

   inline void init (void) {
     head.init ();
     tail.init ();
   }

   inline void add (hb_codepoint_t g) {
     head.add (g);
     tail.add (g);
   }

   inline void add_range (hb_codepoint_t a, hb_codepoint_t b) {
     head.add_range (a, b);
     tail.add_range (a, b);
   }

   inline bool may_have (hb_codepoint_t g) const {
     return head.may_have (g) && tail.may_have (g);
   }

   private:
   head_t head;
   tail_t tail;
 };


 /*
  * hb_set_digest_t
  *
  * This is a combination of digests that performs "best".
  * There is not much science to this: it's a result of intuition
  * and testing.
  */
 typedef hb_set_digest_combiner_t
 <
   hb_set_digest_lowest_bits_t<unsigned long, 4>,
   hb_set_digest_combiner_t
   <
     hb_set_digest_lowest_bits_t<unsigned long, 0>,
     hb_set_digest_lowest_bits_t<unsigned long, 9>
   >
 > hb_set_digest_t;


 /*
  * hb_set_t
  */


 /* TODO Make this faster and memmory efficient. */

 struct hb_set_t
 {
   hb_object_header_t header;
   ASSERT_POD ();
   bool in_error;

   inline void init (void) {
     header.init ();
     clear ();
   }
   inline void fini (void) {
   }
   inline void clear (void) {
     if (unlikely (hb_object_is_inert (this)))
       return;
     in_error = false;
     memset (elts, 0, sizeof elts);
   }
   inline bool is_empty (void) const {
     for (unsigned int i = 0; i < ARRAY_LENGTH (elts); i++)
       if (elts[i])
         return false;
     return true;
   }
   inline void add (hb_codepoint_t g)
   {
     if (unlikely (in_error)) return;
     if (unlikely (g == SENTINEL)) return;
     if (unlikely (g > MAX_G)) return;
     elt (g) |= mask (g);
   }
   inline void add_range (hb_codepoint_t a, hb_codepoint_t b)
   {
     if (unlikely (in_error)) return;
     /* TODO Speedup */
     for (unsigned int i = a; i < b + 1; i++)
       add (i);
   }
   inline void del (hb_codepoint_t g)
   {
     if (unlikely (in_error)) return;
     if (unlikely (g > MAX_G)) return;
     elt (g) &= ~mask (g);
   }
   inline void del_range (hb_codepoint_t a, hb_codepoint_t b)
   {
     if (unlikely (in_error)) return;
     /* TODO Speedup */
     for (unsigned int i = a; i < b + 1; i++)
       del (i);
   }
   inline bool has (hb_codepoint_t g) const
   {
     if (unlikely (g > MAX_G)) return false;
     return !!(elt (g) & mask (g));
   }
   inline bool intersects (hb_codepoint_t first,
 			  hb_codepoint_t last) const
   {
     if (unlikely (first > MAX_G)) return false;
     if (unlikely (last  > MAX_G)) last = MAX_G;
     unsigned int end = last + 1;
     for (hb_codepoint_t i = first; i < end; i++)
       if (has (i))
         return true;
     return false;
   }
   inline bool is_equal (const hb_set_t *other) const
   {
     for (unsigned int i = 0; i < ELTS; i++)
       if (elts[i] != other->elts[i])
         return false;
     return true;
   }
   inline void set (const hb_set_t *other)
   {
     if (unlikely (in_error)) return;
     for (unsigned int i = 0; i < ELTS; i++)
       elts[i] = other->elts[i];
   }
   inline void union_ (const hb_set_t *other)
   {
     if (unlikely (in_error)) return;
     for (unsigned int i = 0; i < ELTS; i++)
       elts[i] |= other->elts[i];
   }
   inline void intersect (const hb_set_t *other)
   {
     if (unlikely (in_error)) return;
     for (unsigned int i = 0; i < ELTS; i++)
       elts[i] &= other->elts[i];
   }
   inline void subtract (const hb_set_t *other)
   {
     if (unlikely (in_error)) return;
     for (unsigned int i = 0; i < ELTS; i++)
       elts[i] &= ~other->elts[i];
   }
   inline void symmetric_difference (const hb_set_t *other)
   {
     if (unlikely (in_error)) return;
     for (unsigned int i = 0; i < ELTS; i++)
       elts[i] ^= other->elts[i];
   }
   inline void invert (void)
   {
     if (unlikely (in_error)) return;
     for (unsigned int i = 0; i < ELTS; i++)
       elts[i] = ~elts[i];
   }
   inline bool next (hb_codepoint_t *codepoint) const
   {
     if (unlikely (*codepoint == SENTINEL)) {
       hb_codepoint_t i = get_min ();
       if (i != SENTINEL) {
         *codepoint = i;
 	return true;
       } else
         return false;
     }
     for (hb_codepoint_t i = *codepoint + 1; i < MAX_G + 1; i++)
       if (has (i)) {
         *codepoint = i;
 	return true;
       }
     return false;
   }
   inline bool next_range (hb_codepoint_t *first, hb_codepoint_t *last) const
   {
     hb_codepoint_t i;

     i = *last;
     if (!next (&i))
       return false;

     *last = *first = i;
     while (next (&i) && i == *last + 1)
       (*last)++;

     return true;
   }

   inline unsigned int get_population (void) const
   {
     unsigned int count = 0;
     for (unsigned int i = 0; i < ELTS; i++)
       count += _hb_popcount32 (elts[i]);
     return count;
   }
   inline hb_codepoint_t get_min (void) const
   {
     for (unsigned int i = 0; i < ELTS; i++)
       if (elts[i])
 	for (unsigned int j = 0; j < BITS; j++)
 	  if (elts[i] & (1 << j))
 	    return i * BITS + j;
     return SENTINEL;
   }
   inline hb_codepoint_t get_max (void) const
   {
     for (unsigned int i = ELTS; i; i--)
       if (elts[i - 1])
 	for (unsigned int j = BITS; j; j--)
 	  if (elts[i - 1] & (1 << (j - 1)))
 	    return (i - 1) * BITS + (j - 1);
     return SENTINEL;
   }

   typedef uint32_t elt_t;
   static const unsigned int MAX_G = 65536 - 1; /* XXX Fix this... */
   static const unsigned int SHIFT = 5;
   static const unsigned int BITS = (1 << SHIFT);
   static const unsigned int MASK = BITS - 1;
   static const unsigned int ELTS = (MAX_G + 1 + (BITS - 1)) / BITS;
   static  const hb_codepoint_t SENTINEL = (hb_codepoint_t) -1;

   elt_t &elt (hb_codepoint_t g) { return elts[g >> SHIFT]; }
   elt_t elt (hb_codepoint_t g) const { return elts[g >> SHIFT]; }
   elt_t mask (hb_codepoint_t g) const { return elt_t (1) << (g & MASK); }

   elt_t elts[ELTS]; /* XXX 8kb */

   ASSERT_STATIC (sizeof (elt_t) * 8 == BITS);
   ASSERT_STATIC (sizeof (elt_t) * 8 * ELTS > MAX_G);
 };


 #endif /* HB_SET_PRIVATE_HH */
	/*
	* Copyright © 2012 Google, Inc.
	*
	* 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_SET_PRIVATE_HH
	#define HB_SET_PRIVATE_HH

	#include "hb-private.hh"
	#include "hb-set.h"
	#include "hb-object-private.hh"


	/*
	* The set digests here implement various "filters" that support
	* "approximate member query". Conceptually these are like Bloom
	* Filter and Quotient Filter, however, much smaller, faster, and
	* designed to fit the requirements of our uses for glyph coverage
	* queries. As a result, our filters have much higher.
	*/

	template <typename mask_t, unsigned int shift>
	struct hb_set_digest_lowest_bits_t
	{
	ASSERT_POD ();

	static const unsigned int mask_bytes = sizeof (mask_t);
	static const unsigned int mask_bits = sizeof (mask_t) * 8;
	static const unsigned int num_bits = 0
	+ (mask_bytes >= 1 ? 3 : 0)
	+ (mask_bytes >= 2 ? 1 : 0)
	+ (mask_bytes >= 4 ? 1 : 0)
	+ (mask_bytes >= 8 ? 1 : 0)
	+ (mask_bytes >= 16? 1 : 0)
	+ 0;

	ASSERT_STATIC (shift < sizeof (hb_codepoint_t) * 8);
	ASSERT_STATIC (shift + num_bits <= sizeof (hb_codepoint_t) * 8);

	inline void init (void) {
	mask = 0;
	}

	inline void add (hb_codepoint_t g) {
	mask \|= mask_for (g);
	}

	inline void add_range (hb_codepoint_t a, hb_codepoint_t b) {
	if ((b >> shift) - (a >> shift) >= mask_bits - 1)
	mask = (mask_t) -1;
	else {
	mask_t ma = mask_for (a);
	mask_t mb = mask_for (b);
	mask \|= mb + (mb - ma) - (mb < ma);
	}
	}

	inline bool may_have (hb_codepoint_t g) const {
	return !!(mask & mask_for (g));
	}

	private:

	static inline mask_t mask_for (hb_codepoint_t g) {
	return ((mask_t) 1) << ((g >> shift) & (mask_bits - 1));
	}
	mask_t mask;
	};

	template <typename head_t, typename tail_t>
	struct hb_set_digest_combiner_t
	{
	ASSERT_POD ();

	inline void init (void) {
	head.init ();
	tail.init ();
	}

	inline void add (hb_codepoint_t g) {
	head.add (g);
	tail.add (g);
	}

	inline void add_range (hb_codepoint_t a, hb_codepoint_t b) {
	head.add_range (a, b);
	tail.add_range (a, b);
	}

	inline bool may_have (hb_codepoint_t g) const {
	return head.may_have (g) && tail.may_have (g);
	}

	private:
	head_t head;
	tail_t tail;
	};


	/*
	* hb_set_digest_t
	*
	* This is a combination of digests that performs "best".
	* There is not much science to this: it's a result of intuition
	* and testing.
	*/
	typedef hb_set_digest_combiner_t
	<
	hb_set_digest_lowest_bits_t<unsigned long, 4>,
	hb_set_digest_combiner_t
	<
	hb_set_digest_lowest_bits_t<unsigned long, 0>,
	hb_set_digest_lowest_bits_t<unsigned long, 9>
	>
	> hb_set_digest_t;



	/*
	* hb_set_t
	*/


	/* TODO Make this faster and memmory efficient. */

	struct hb_set_t
	{
	hb_object_header_t header;
	ASSERT_POD ();
	bool in_error;

	inline void init (void) {
	header.init ();
	clear ();
	}
	inline void fini (void) {
	}
	inline void clear (void) {
	if (unlikely (hb_object_is_inert (this)))
	return;
	in_error = false;
	memset (elts, 0, sizeof elts);
	}
	inline bool is_empty (void) const {
	for (unsigned int i = 0; i < ARRAY_LENGTH (elts); i++)
	if (elts[i])
	return false;
	return true;
	}
	inline void add (hb_codepoint_t g)
	{
	if (unlikely (in_error)) return;
	if (unlikely (g == SENTINEL)) return;
	if (unlikely (g > MAX_G)) return;
	elt (g) \|= mask (g);
	}
	inline void add_range (hb_codepoint_t a, hb_codepoint_t b)
	{
	if (unlikely (in_error)) return;
	/* TODO Speedup */
	for (unsigned int i = a; i < b + 1; i++)
	add (i);
	}
	inline void del (hb_codepoint_t g)
	{
	if (unlikely (in_error)) return;
	if (unlikely (g > MAX_G)) return;
	elt (g) &= ~mask (g);
	}
	inline void del_range (hb_codepoint_t a, hb_codepoint_t b)
	{
	if (unlikely (in_error)) return;
	/* TODO Speedup */
	for (unsigned int i = a; i < b + 1; i++)
	del (i);
	}
	inline bool has (hb_codepoint_t g) const
	{
	if (unlikely (g > MAX_G)) return false;
	return !!(elt (g) & mask (g));
	}
	inline bool intersects (hb_codepoint_t first,
	hb_codepoint_t last) const
	{
	if (unlikely (first > MAX_G)) return false;
	if (unlikely (last > MAX_G)) last = MAX_G;
	unsigned int end = last + 1;
	for (hb_codepoint_t i = first; i < end; i++)
	if (has (i))
	return true;
	return false;
	}
	inline bool is_equal (const hb_set_t *other) const
	{
	for (unsigned int i = 0; i < ELTS; i++)
	if (elts[i] != other->elts[i])
	return false;
	return true;
	}
	inline void set (const hb_set_t *other)
	{
	if (unlikely (in_error)) return;
	for (unsigned int i = 0; i < ELTS; i++)
	elts[i] = other->elts[i];
	}
	inline void union_ (const hb_set_t *other)
	{
	if (unlikely (in_error)) return;
	for (unsigned int i = 0; i < ELTS; i++)
	elts[i] \|= other->elts[i];
	}
	inline void intersect (const hb_set_t *other)
	{
	if (unlikely (in_error)) return;
	for (unsigned int i = 0; i < ELTS; i++)
	elts[i] &= other->elts[i];
	}
	inline void subtract (const hb_set_t *other)
	{
	if (unlikely (in_error)) return;
	for (unsigned int i = 0; i < ELTS; i++)
	elts[i] &= ~other->elts[i];
	}
	inline void symmetric_difference (const hb_set_t *other)
	{
	if (unlikely (in_error)) return;
	for (unsigned int i = 0; i < ELTS; i++)
	elts[i] ^= other->elts[i];
	}
	inline void invert (void)
	{
	if (unlikely (in_error)) return;
	for (unsigned int i = 0; i < ELTS; i++)
	elts[i] = ~elts[i];
	}
	inline bool next (hb_codepoint_t *codepoint) const
	{
	if (unlikely (*codepoint == SENTINEL)) {
	hb_codepoint_t i = get_min ();
	if (i != SENTINEL) {
	*codepoint = i;
	return true;
	} else
	return false;
	}
	for (hb_codepoint_t i = *codepoint + 1; i < MAX_G + 1; i++)
	if (has (i)) {
	*codepoint = i;
	return true;
	}
	return false;
	}
	inline bool next_range (hb_codepoint_t first, hb_codepoint_t last) const
	{
	hb_codepoint_t i;

	i = *last;
	if (!next (&i))
	return false;

	last = first = i;
	while (next (&i) && i == *last + 1)
	(*last)++;

	return true;
	}

	inline unsigned int get_population (void) const
	{
	unsigned int count = 0;
	for (unsigned int i = 0; i < ELTS; i++)
	count += _hb_popcount32 (elts[i]);
	return count;
	}
	inline hb_codepoint_t get_min (void) const
	{
	for (unsigned int i = 0; i < ELTS; i++)
	if (elts[i])
	for (unsigned int j = 0; j < BITS; j++)
	if (elts[i] & (1 << j))
	return i * BITS + j;
	return SENTINEL;
	}
	inline hb_codepoint_t get_max (void) const
	{
	for (unsigned int i = ELTS; i; i--)
	if (elts[i - 1])
	for (unsigned int j = BITS; j; j--)
	if (elts[i - 1] & (1 << (j - 1)))
	return (i - 1) * BITS + (j - 1);
	return SENTINEL;
	}

	typedef uint32_t elt_t;
	static const unsigned int MAX_G = 65536 - 1; /* XXX Fix this... */
	static const unsigned int SHIFT = 5;
	static const unsigned int BITS = (1 << SHIFT);
	static const unsigned int MASK = BITS - 1;
	static const unsigned int ELTS = (MAX_G + 1 + (BITS - 1)) / BITS;
	static const hb_codepoint_t SENTINEL = (hb_codepoint_t) -1;

	elt_t &elt (hb_codepoint_t g) { return elts[g >> SHIFT]; }
	elt_t elt (hb_codepoint_t g) const { return elts[g >> SHIFT]; }
	elt_t mask (hb_codepoint_t g) const { return elt_t (1) << (g & MASK); }

	elt_t elts[ELTS]; /* XXX 8kb */

	ASSERT_STATIC (sizeof (elt_t) * 8 == BITS);
	ASSERT_STATIC (sizeof (elt_t) * 8 * ELTS > MAX_G);
	};



	#endif /* HB_SET_PRIVATE_HH */