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https://github.com/MariaDB/server.git
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228 lines
7.2 KiB
C++
228 lines
7.2 KiB
C++
/* Copyright (c) 2003, 2013, Oracle and/or its affiliates
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Copyright (c) 2009, 2013, Monty Program Ab.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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/*
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Implementation of a bitmap type.
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The idea with this is to be able to handle any constant number of bits but
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also be able to use 32 or 64 bits bitmaps very efficiently
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*/
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#ifndef SQL_BITMAP_INCLUDED
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#define SQL_BITMAP_INCLUDED
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#include <my_sys.h>
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#include <my_bitmap.h>
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template <uint default_width> class Bitmap
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{
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MY_BITMAP map;
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uint32 buffer[(default_width+31)/32];
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public:
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Bitmap() { init(); }
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Bitmap(const Bitmap& from) { *this=from; }
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explicit Bitmap(uint prefix_to_set) { init(prefix_to_set); }
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void init() { my_bitmap_init(&map, buffer, default_width, 0); }
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void init(uint prefix_to_set) { init(); set_prefix(prefix_to_set); }
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uint length() const { return default_width; }
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Bitmap& operator=(const Bitmap& map2)
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{
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init();
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memcpy(buffer, map2.buffer, sizeof(buffer));
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return *this;
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}
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void set_bit(uint n) { bitmap_set_bit(&map, n); }
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void clear_bit(uint n) { bitmap_clear_bit(&map, n); }
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void set_prefix(uint n) { bitmap_set_prefix(&map, n); }
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void set_all() { bitmap_set_all(&map); }
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void clear_all() { bitmap_clear_all(&map); }
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void intersect(Bitmap& map2) { bitmap_intersect(&map, &map2.map); }
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void intersect(ulonglong map2buff)
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{
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// Use a spearate temporary buffer, as bitmap_init() clears all the bits.
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ulonglong buf2;
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MY_BITMAP map2;
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my_bitmap_init(&map2, (uint32 *) &buf2, sizeof(ulonglong) * 8, 0);
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// Store the original bits.
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if (sizeof(ulonglong) >= 8)
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{
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int8store(const_cast<uchar *>(static_cast<uchar *>
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(static_cast<void *>(&buf2))),
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map2buff);
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}
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else
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{
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DBUG_ASSERT(sizeof(buffer) >= 4);
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int4store(const_cast<uchar *>(static_cast<uchar *>
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(static_cast<void *>(&buf2))),
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static_cast<uint32>(map2buff));
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}
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bitmap_intersect(&map, &map2);
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}
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/* Use highest bit for all bits above sizeof(ulonglong)*8. */
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void intersect_extended(ulonglong map2buff)
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{
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intersect(map2buff);
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if (map.n_bits > sizeof(ulonglong) * 8)
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bitmap_set_above(&map, sizeof(ulonglong),
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MY_TEST(map2buff & (1LL << (sizeof(ulonglong) * 8 - 1))));
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}
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void subtract(Bitmap& map2) { bitmap_subtract(&map, &map2.map); }
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void merge(Bitmap& map2) { bitmap_union(&map, &map2.map); }
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bool is_set(uint n) const { return bitmap_is_set(&map, n); }
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bool is_prefix(uint n) const { return bitmap_is_prefix(&map, n); }
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bool is_clear_all() const { return bitmap_is_clear_all(&map); }
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bool is_set_all() const { return bitmap_is_set_all(&map); }
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bool is_subset(const Bitmap& map2) const { return bitmap_is_subset(&map, &map2.map); }
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bool is_overlapping(const Bitmap& map2) const { return bitmap_is_overlapping(&map, &map2.map); }
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bool operator==(const Bitmap& map2) const { return bitmap_cmp(&map, &map2.map); }
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bool operator!=(const Bitmap& map2) const { return !(*this == map2); }
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char *print(char *buf) const
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{
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char *s=buf;
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const uchar *e=(uchar *)buffer, *b=e+sizeof(buffer)-1;
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while (!*b && b>e)
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b--;
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if ((*s=_dig_vec_upper[*b >> 4]) != '0')
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s++;
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*s++=_dig_vec_upper[*b & 15];
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while (--b>=e)
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{
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*s++=_dig_vec_upper[*b >> 4];
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*s++=_dig_vec_upper[*b & 15];
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}
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*s=0;
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return buf;
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}
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ulonglong to_ulonglong() const
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{
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if (sizeof(buffer) >= 8)
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return uint8korr(static_cast<const uchar *>
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(static_cast<const void *>(buffer)));
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DBUG_ASSERT(sizeof(buffer) >= 4);
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return (ulonglong)
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uint4korr(static_cast<const uchar *>
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(static_cast<const void *>(buffer)));
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}
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uint bits_set()
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{
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return bitmap_bits_set(&map);
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}
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class Iterator
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{
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Bitmap ↦
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uint no;
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public:
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Iterator(Bitmap<default_width> &map2): map(map2), no(0) {}
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int operator++(int) {
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if (no == default_width) return BITMAP_END;
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while (!map.is_set(no))
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{
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if ((++no) == default_width) return BITMAP_END;
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}
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return no ++;
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}
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enum { BITMAP_END= default_width };
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};
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};
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/* An iterator to quickly walk over bits in ulonglong bitmap. */
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class Table_map_iterator
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{
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ulonglong bmp;
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uint no;
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public:
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Table_map_iterator(ulonglong t) : bmp(t), no(0) {}
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uint next_bit()
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{
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static const uchar last_bit[16]= {32, 0, 1, 0,
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2, 0, 1, 0,
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3, 0, 1, 0,
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2, 0, 1, 0};
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uint bit;
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while ((bit= last_bit[bmp & 0xF]) == 32)
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{
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no += 4;
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bmp= bmp >> 4;
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if (!bmp)
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return BITMAP_END;
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}
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bmp &= ~(1ULL << bit);
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return no + bit;
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}
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uint operator++(int) { return next_bit(); }
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enum { BITMAP_END= 64 };
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};
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template <> class Bitmap<64>
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{
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ulonglong map;
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public:
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Bitmap<64>() { }
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explicit Bitmap<64>(uint prefix_to_set) { set_prefix(prefix_to_set); }
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void init() { }
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void init(uint prefix_to_set) { set_prefix(prefix_to_set); }
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uint length() const { return 64; }
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void set_bit(uint n) { map|= ((ulonglong)1) << n; }
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void clear_bit(uint n) { map&= ~(((ulonglong)1) << n); }
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void set_prefix(uint n)
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{
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if (n >= length())
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set_all();
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else
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map= (((ulonglong)1) << n)-1;
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}
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void set_all() { map=~(ulonglong)0; }
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void clear_all() { map=(ulonglong)0; }
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void intersect(Bitmap<64>& map2) { map&= map2.map; }
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void intersect(ulonglong map2) { map&= map2; }
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void intersect_extended(ulonglong map2) { map&= map2; }
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void subtract(Bitmap<64>& map2) { map&= ~map2.map; }
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void merge(Bitmap<64>& map2) { map|= map2.map; }
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bool is_set(uint n) const { return MY_TEST(map & (((ulonglong) 1) << n)); }
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bool is_prefix(uint n) const { return map == (((ulonglong)1) << n)-1; }
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bool is_clear_all() const { return map == (ulonglong)0; }
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bool is_set_all() const { return map == ~(ulonglong)0; }
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bool is_subset(const Bitmap<64>& map2) const { return !(map & ~map2.map); }
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bool is_overlapping(const Bitmap<64>& map2) const { return (map & map2.map)!= 0; }
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bool operator==(const Bitmap<64>& map2) const { return map == map2.map; }
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char *print(char *buf) const {
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longlong2str(longlong(map), buf, 16);
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return buf;
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}
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ulonglong to_ulonglong() const { return map; }
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class Iterator : public Table_map_iterator
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{
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public:
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Iterator(Bitmap<64> &map2) : Table_map_iterator(map2.map) {}
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};
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uint bits_set()
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{
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//TODO: use my_count_bits()
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uint res= 0, i= 0;
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for (; i < 64 ; i++)
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{
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if (map & ((ulonglong)1<<i))
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res++;
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}
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return res;
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}
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};
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#endif /* SQL_BITMAP_INCLUDED */
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