From 354bb40e75d94466e91fe6960523612c9d17ccfb Mon Sep 17 00:00:00 2001 From: Karen Arutyunov Date: Thu, 2 Nov 2017 23:11:29 +0300 Subject: Add implementation --- mysql/mysys/my_bitmap.c | 672 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 672 insertions(+) create mode 100644 mysql/mysys/my_bitmap.c (limited to 'mysql/mysys/my_bitmap.c') diff --git a/mysql/mysys/my_bitmap.c b/mysql/mysys/my_bitmap.c new file mode 100644 index 0000000..10a345c --- /dev/null +++ b/mysql/mysys/my_bitmap.c @@ -0,0 +1,672 @@ +/* + Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */ + +/* + Handling of uchar arrays as large bitmaps. + + API limitations (or, rather asserted safety assumptions, + to encourage correct programming) + + * the internal size is a set of 32 bit words + * the number of bits specified in creation can be any number > 0 + a bitmap with zero bits can be created and initialized, but not used. + * there are THREAD safe versions of most calls called bitmap_lock_* + + TODO: + Make assembler THREAD safe versions of these using test-and-set instructions + + Original version created by Sergei Golubchik 2001 - 2004. + New version written and test program added and some changes to the interface + was made by Mikael Ronström 2005, with assistance of Tomas Ulin and Mats + Kindahl. +*/ + +#include "mysys_priv.h" +#include "my_sys.h" +#include +#include +#include + +void create_last_word_mask(MY_BITMAP *map) +{ + /* Get the number of used bits (1..8) in the last byte */ + unsigned int const used= 1U + ((map->n_bits-1U) & 0x7U); + + /* + Create a mask with the upper 'unused' bits set and the lower 'used' + bits clear. The bits within each byte is stored in big-endian order. + */ + unsigned char const mask= (~((1 << used) - 1)) & 255; + + /* + The first bytes are to be set to zero since they represent real bits + in the bitvector. The last bytes are set to 0xFF since they represent + bytes not used by the bitvector. Finally the last byte contains bits + as set by the mask above. + */ + unsigned char *ptr= (unsigned char*)&map->last_word_mask; + + /* Avoid out-of-bounds read/write if we have zero bits. */ + map->last_word_ptr= map->n_bits == 0 ? map->bitmap : + map->bitmap + no_words_in_map(map) - 1; + + switch (no_bytes_in_map(map) & 3) { + case 1: + map->last_word_mask= ~0U; + ptr[0]= mask; + return; + case 2: + map->last_word_mask= ~0U; + ptr[0]= 0; + ptr[1]= mask; + return; + case 3: + map->last_word_mask= 0U; + ptr[2]= mask; + ptr[3]= 0xFFU; + return; + case 0: + map->last_word_mask= 0U; + ptr[3]= mask; + return; + } +} + + +static inline void bitmap_lock(MY_BITMAP *map MY_ATTRIBUTE((unused))) +{ + if (map->mutex) + mysql_mutex_lock(map->mutex); +} + + +static inline void bitmap_unlock(MY_BITMAP *map MY_ATTRIBUTE((unused))) +{ + if (map->mutex) + mysql_mutex_unlock(map->mutex); +} + + +static inline uint get_first_set(uint32 value, uint word_pos) +{ + uchar *byte_ptr= (uchar*)&value; + uchar byte_value; + uint byte_pos, bit_pos; + + for (byte_pos=0; byte_pos < 4; byte_pos++, byte_ptr++) + { + byte_value= *byte_ptr; + if (byte_value) + { + for (bit_pos=0; ; bit_pos++) + if (byte_value & (1 << bit_pos)) + return (word_pos*32) + (byte_pos*8) + bit_pos; + } + } + return MY_BIT_NONE; +} + + +static inline uint get_first_not_set(uint32 value, uint word_pos) +{ + uchar *byte_ptr= (uchar*)&value; + uchar byte_value; + uint byte_pos, bit_pos; + + for (byte_pos=0; byte_pos < 4; byte_pos++, byte_ptr++) + { + byte_value= *byte_ptr; + if (byte_value != 0xFF) + { + for (bit_pos=0; ; bit_pos++) + if (!(byte_value & (1 << bit_pos))) + return (word_pos*32) + (byte_pos*8) + bit_pos; + } + } + return MY_BIT_NONE; +} + + +my_bool bitmap_init(MY_BITMAP *map, my_bitmap_map *buf, uint n_bits, + my_bool thread_safe MY_ATTRIBUTE((unused))) +{ + DBUG_ENTER("bitmap_init"); + if (!buf) + { + uint size_in_bytes= bitmap_buffer_size(n_bits); + uint extra= 0; + + if (thread_safe) + { + size_in_bytes= ALIGN_SIZE(size_in_bytes); + extra= sizeof(mysql_mutex_t); + } + map->mutex= 0; + + if (!(buf= (my_bitmap_map*) my_malloc(key_memory_MY_BITMAP_bitmap, + size_in_bytes+extra, MYF(MY_WME)))) + DBUG_RETURN(1); + + if (thread_safe) + { + map->mutex= (mysql_mutex_t *) ((char*) buf + size_in_bytes); + mysql_mutex_init(key_BITMAP_mutex, map->mutex, MY_MUTEX_INIT_FAST); + } + + } + + else + { + DBUG_ASSERT(thread_safe == 0); + map->mutex= NULL; + } + + + map->bitmap= buf; + map->n_bits= n_bits; + create_last_word_mask(map); + bitmap_clear_all(map); + DBUG_RETURN(0); +} + + +void bitmap_free(MY_BITMAP *map) +{ + DBUG_ENTER("bitmap_free"); + if (map->bitmap) + { + if (map->mutex) + mysql_mutex_destroy(map->mutex); + + my_free(map->bitmap); + map->bitmap=0; + } + DBUG_VOID_RETURN; +} + + +/* + test if bit already set and set it if it was not (thread unsafe method) + + SYNOPSIS + bitmap_fast_test_and_set() + MAP bit map struct + BIT bit number + + RETURN + 0 bit was not set + !=0 bit was set +*/ + +my_bool bitmap_fast_test_and_set(MY_BITMAP *map, uint bitmap_bit) +{ + uchar *value= ((uchar*) map->bitmap) + (bitmap_bit / 8); + uchar bit= 1 << ((bitmap_bit) & 7); + uchar res= (*value) & bit; + *value|= bit; + return res; +} + + +/* + test if bit already set and set it if it was not (thread safe method) + + SYNOPSIS + bitmap_fast_test_and_set() + map bit map struct + bitmap_bit bit number + + RETURN + 0 bit was not set + !=0 bit was set +*/ + +my_bool bitmap_test_and_set(MY_BITMAP *map, uint bitmap_bit) +{ + my_bool res; + DBUG_ASSERT(map->bitmap && bitmap_bit < map->n_bits); + bitmap_lock(map); + res= bitmap_fast_test_and_set(map, bitmap_bit); + bitmap_unlock(map); + return res; +} + +/* + test if bit already set and clear it if it was set(thread unsafe method) + + SYNOPSIS + bitmap_fast_test_and_set() + MAP bit map struct + BIT bit number + + RETURN + 0 bit was not set + !=0 bit was set +*/ + +my_bool bitmap_fast_test_and_clear(MY_BITMAP *map, uint bitmap_bit) +{ + uchar *byte= (uchar*) map->bitmap + (bitmap_bit / 8); + uchar bit= 1 << ((bitmap_bit) & 7); + uchar res= (*byte) & bit; + *byte&= ~bit; + return res; +} + + +my_bool bitmap_test_and_clear(MY_BITMAP *map, uint bitmap_bit) +{ + my_bool res; + DBUG_ASSERT(map->bitmap && bitmap_bit < map->n_bits); + bitmap_lock(map); + res= bitmap_fast_test_and_clear(map, bitmap_bit); + bitmap_unlock(map); + return res; +} + + +uint bitmap_set_next(MY_BITMAP *map) +{ + uint bit_found; + DBUG_ASSERT(map->bitmap); + if ((bit_found= bitmap_get_first(map)) != MY_BIT_NONE) + bitmap_set_bit(map, bit_found); + return bit_found; +} + + +/** + Set the specified number of bits in the bitmap buffer. + + @param map [IN] Bitmap + @param prefix_size [IN] Number of bits to be set + + @return void +*/ +void bitmap_set_prefix(MY_BITMAP *map, uint prefix_size) +{ + uint prefix_bytes, prefix_bits, d; + uchar *m= (uchar *)map->bitmap; + + DBUG_ASSERT(map->bitmap && + (prefix_size <= map->n_bits || prefix_size == (uint) ~0)); + set_if_smaller(prefix_size, map->n_bits); + if ((prefix_bytes= prefix_size / 8)) + memset(m, 0xff, prefix_bytes); + m+= prefix_bytes; + if ((prefix_bits= prefix_size & 7)) + { + *(m++)= (1 << prefix_bits)-1; + // As the prefix bits are set, lets count this byte too as a prefix byte. + prefix_bytes ++; + } + if ((d= no_bytes_in_map(map)-prefix_bytes)) + memset(m, 0, d); +} + + +my_bool bitmap_is_prefix(const MY_BITMAP *map, uint prefix_size) +{ + uint prefix_bits= prefix_size % 32; + my_bitmap_map *word_ptr= map->bitmap, last_word; + my_bitmap_map *end_prefix= word_ptr + prefix_size / 32; + DBUG_ASSERT(word_ptr && prefix_size <= map->n_bits); + + /* 1: Words that should be filled with 1 */ + for (; word_ptr < end_prefix; word_ptr++) + if (*word_ptr != 0xFFFFFFFF) + return FALSE; + + DBUG_ASSERT(map->n_bits > 0); + last_word= *map->last_word_ptr & ~map->last_word_mask; + + /* 2: Word which contains the end of the prefix (if any) */ + if (prefix_bits) + { + if (word_ptr == map->last_word_ptr) + return uint4korr((uchar*)&last_word) == (uint32)((1 << prefix_bits) - 1); + else if (uint4korr((uchar*)word_ptr) != (uint32)((1 << prefix_bits) - 1)) + return FALSE; + word_ptr++; + } + + /* 3: Words that should be filled with 0 */ + for (; word_ptr < map->last_word_ptr; word_ptr++) + if (*word_ptr != 0) + return FALSE; + + /* + We can end up here in two situations: + 1) We went through the whole bitmap in step 1. This will happen if the + whole bitmap is filled with 1 and prefix_size is a multiple of 32 + (i.e. the prefix does not end in the middle of a word). + In this case word_ptr will be larger than map->last_word_ptr. + 2) We have gone through steps 1-3 and just need to check that also + the last word is 0. + */ + return word_ptr > map->last_word_ptr || last_word == 0; +} + + +my_bool bitmap_is_set_all(const MY_BITMAP *map) +{ + my_bitmap_map *data_ptr= map->bitmap; + my_bitmap_map *end= map->last_word_ptr; + + DBUG_ASSERT(map->n_bits > 0); + for (; data_ptr < end; data_ptr++) + if (*data_ptr != 0xFFFFFFFF) + return FALSE; + if ((*map->last_word_ptr | map->last_word_mask) != 0xFFFFFFFF) + return FALSE; + return TRUE; +} + + +my_bool bitmap_is_clear_all(const MY_BITMAP *map) +{ + my_bitmap_map *data_ptr= map->bitmap; + my_bitmap_map *end= map->last_word_ptr; + + DBUG_ASSERT(map->n_bits > 0); + for (; data_ptr < end; data_ptr++) + if (*data_ptr) + return FALSE; + if (*map->last_word_ptr & ~map->last_word_mask) + return FALSE; + return TRUE; +} + +/* Return TRUE if map1 is a subset of map2 */ + +my_bool bitmap_is_subset(const MY_BITMAP *map1, const MY_BITMAP *map2) +{ + my_bitmap_map *m1= map1->bitmap, *m2= map2->bitmap, *end; + + DBUG_ASSERT(map1->bitmap && map2->bitmap && + map1->n_bits==map2->n_bits); + + end= map1->last_word_ptr; + for (; m1 < end; m1++, m2++) + if (*m1 & ~(*m2)) + return FALSE; + + DBUG_ASSERT(map1->n_bits > 0); + DBUG_ASSERT(map2->n_bits > 0); + + if ((*map1->last_word_ptr & ~map1->last_word_mask) & + ~(*map2->last_word_ptr & ~map2->last_word_mask)) + return FALSE; + return TRUE; +} + +/* True if bitmaps has any common bits */ + +my_bool bitmap_is_overlapping(const MY_BITMAP *map1, const MY_BITMAP *map2) +{ + my_bitmap_map *m1= map1->bitmap, *m2= map2->bitmap, *end; + + DBUG_ASSERT(map1->bitmap && map2->bitmap && + map1->n_bits==map2->n_bits); + + DBUG_ASSERT(map1->n_bits > 0); + DBUG_ASSERT(map2->n_bits > 0); + + end= map1->last_word_ptr; + for (; m1 < end; m1++, m2++) + if (*m1 & *m2) + return TRUE; + + if ((*map1->last_word_ptr & ~map1->last_word_mask) & + (*map2->last_word_ptr & ~map2->last_word_mask)) + return TRUE; + return FALSE; +} + + +void bitmap_intersect(MY_BITMAP *map, const MY_BITMAP *map2) +{ + my_bitmap_map *to= map->bitmap, *from= map2->bitmap, *end; + uint len= no_words_in_map(map), len2 = no_words_in_map(map2); + + DBUG_ASSERT(map->bitmap && map2->bitmap); + + end= to + MY_MIN(len, len2); + for (; to < end; to++, from++) + *to &= *from; + + if (len >= len2) + map->bitmap[len2 - 1] &= ~map2->last_word_mask; + + if (len2 < len) + { + end+=len-len2; + for (; to < end; to++) + *to= 0; + } +} + + +/* + Set/clear all bits above a bit. + + SYNOPSIS + bitmap_set_above() + map RETURN The bitmap to change. + from_byte The bitmap buffer byte offset to start with. + use_bit The bit value (1/0) to use for all upper bits. + + NOTE + You can only set/clear full bytes. + The function is meant for the situation that you copy a smaller bitmap + to a bigger bitmap. Bitmap lengths are always multiple of eigth (the + size of a byte). Using 'from_byte' saves multiplication and division + by eight during parameter passing. + + RETURN + void +*/ + +void bitmap_set_above(MY_BITMAP *map, uint from_byte, uint use_bit) +{ + uchar use_byte= use_bit ? 0xff : 0; + uchar *to= (uchar *)map->bitmap + from_byte; + uchar *end= (uchar *)map->bitmap + (map->n_bits+7)/8; + + for (; to < end; to++) + *to= use_byte; +} + + +void bitmap_subtract(MY_BITMAP *map, const MY_BITMAP *map2) +{ + my_bitmap_map *to= map->bitmap, *from= map2->bitmap, *end; + DBUG_ASSERT(map->bitmap && map2->bitmap && + map->n_bits==map2->n_bits); + DBUG_ASSERT(map->n_bits > 0); + end= map->last_word_ptr; + + for (; to <= end; to++, from++) + *to &= ~(*from); +} + + +void bitmap_union(MY_BITMAP *map, const MY_BITMAP *map2) +{ + my_bitmap_map *to= map->bitmap, *from= map2->bitmap, *end; + DBUG_ASSERT(map->bitmap && map2->bitmap && + map->n_bits==map2->n_bits); + DBUG_ASSERT(map->n_bits > 0); + end= map->last_word_ptr; + + for (; to <= end; to++, from++) + *to |= *from; +} + + +void bitmap_xor(MY_BITMAP *map, const MY_BITMAP *map2) +{ + my_bitmap_map *to= map->bitmap, *from= map2->bitmap, *end; + DBUG_ASSERT(map->bitmap && map2->bitmap && + map->n_bits==map2->n_bits); + DBUG_ASSERT(map->n_bits > 0); + end= map->last_word_ptr; + + for (; to <= end; to++, from++) + *to ^= *from; +} + + +void bitmap_invert(MY_BITMAP *map) +{ + my_bitmap_map *to= map->bitmap, *end; + DBUG_ASSERT(map->bitmap); + DBUG_ASSERT(map->n_bits > 0); + end= map->last_word_ptr; + + for (; to <= end; to++) + *to ^= 0xFFFFFFFF; +} + + +uint bitmap_bits_set(const MY_BITMAP *map) +{ + my_bitmap_map *data_ptr= map->bitmap; + my_bitmap_map *end= map->last_word_ptr; + uint res= 0; + DBUG_ASSERT(map->bitmap); + DBUG_ASSERT(map->n_bits > 0); + + for (; data_ptr < end; data_ptr++) + res+= my_count_bits_uint32(*data_ptr); + + /*Reset last bits to zero*/ + res+= my_count_bits_uint32(*map->last_word_ptr & ~map->last_word_mask); + return res; +} + + +void bitmap_copy(MY_BITMAP *map, const MY_BITMAP *map2) +{ + my_bitmap_map *to= map->bitmap, *from= map2->bitmap, *end; + DBUG_ASSERT(map->bitmap && map2->bitmap && + map->n_bits==map2->n_bits); + DBUG_ASSERT(map->n_bits > 0); + end= map->last_word_ptr; + + for (; to <= end; to++, from++) + *to = *from; +} + + +uint bitmap_get_first_set(const MY_BITMAP *map) +{ + uint word_pos; + my_bitmap_map *data_ptr, *end= map->last_word_ptr; + + DBUG_ASSERT(map->bitmap); + DBUG_ASSERT(map->n_bits > 0); + data_ptr= map->bitmap; + + for (word_pos=0; data_ptr < end; data_ptr++, word_pos++) + if (*data_ptr) + return get_first_set(*data_ptr, word_pos); + + return get_first_set(*map->last_word_ptr & ~map->last_word_mask, word_pos); +} + + +/** + Get the next set bit. + + @param map Bitmap + @param bitmap_bit Bit to start search from + + @return Index to first bit set after bitmap_bit +*/ + +uint bitmap_get_next_set(const MY_BITMAP *map, uint bitmap_bit) +{ + uint word_pos, byte_to_mask, i; + my_bitmap_map first_word; + unsigned char *ptr= (unsigned char*) &first_word; + my_bitmap_map *data_ptr, *end= map->last_word_ptr; + + DBUG_ASSERT(map->bitmap); + DBUG_ASSERT(map->n_bits > 0); + + /* Look for the next bit */ + bitmap_bit++; + if (bitmap_bit >= map->n_bits) + return MY_BIT_NONE; + word_pos= bitmap_bit / 32; + data_ptr= map->bitmap + word_pos; + first_word= *data_ptr; + + /* Mask out previous bits */ + byte_to_mask= (bitmap_bit % 32) / 8; + for (i= 0; i < byte_to_mask; i++) + ptr[i]= 0; + ptr[byte_to_mask]&= 0xFFU << (bitmap_bit & 7); + + if (data_ptr == end) + return get_first_set(first_word & ~map->last_word_mask, word_pos); + + if (first_word) + return get_first_set(first_word, word_pos); + + for (data_ptr++, word_pos++; data_ptr < end; data_ptr++, word_pos++) + if (*data_ptr) + return get_first_set(*data_ptr, word_pos); + + return get_first_set(*end & ~map->last_word_mask, word_pos); +} + + +uint bitmap_get_first(const MY_BITMAP *map) +{ + uint word_pos; + my_bitmap_map *data_ptr, *end= map->last_word_ptr; + + DBUG_ASSERT(map->bitmap); + DBUG_ASSERT(map->n_bits > 0); + data_ptr= map->bitmap; + + for (word_pos=0; data_ptr < end; data_ptr++, word_pos++) + if (*data_ptr != 0xFFFFFFFF) + return get_first_not_set(*data_ptr, word_pos); + + return get_first_not_set(*map->last_word_ptr | map->last_word_mask, word_pos); +} + + +uint bitmap_lock_set_next(MY_BITMAP *map) +{ + uint bit_found; + bitmap_lock(map); + bit_found= bitmap_set_next(map); + bitmap_unlock(map); + return bit_found; +} + + +void bitmap_lock_clear_bit(MY_BITMAP *map, uint bitmap_bit) +{ + bitmap_lock(map); + DBUG_ASSERT(map->bitmap && bitmap_bit < map->n_bits); + bitmap_clear_bit(map, bitmap_bit); + bitmap_unlock(map); +} -- cgit v1.1