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BrianLeishman/bid.c

Last active Dec 20, 2017
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BID for MySQL (9-byte, time based ID generator)
/*
* Copyright (c) 2017, Brian Leishman
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* USAGE INSTRUCTIONS:
*
* make sure libmysqlclient-dev is installed:
* apt-get install libmysqlclient-dev
*
* Replace "/usr/lib/mysql/plugin" with your MySQL plugins directory (can be found by running "select @@plugin_dir;")
* gcc -I/usr/include/mysql -o bid.so -shared bid.c -fPIC && cp bid.so /usr/lib/mysql/plugin/bid.so
*
* Then, on the server:
* create function`bid`returns string soname'bid.so';
*
* And use/test like:
* select `bid`();
*
* Also, make sure to store in a "BINARY(9)" column type
*
* Yeet!
*
*/
#ifdef STANDARD
/* STANDARD is defined, don't use any mysql functions */
#include <string.h>
#ifdef __WIN__
typedef unsigned __int64 ulonglong; /* Microsofts 64 bit types */
typedef __int64 longlong;
#else
typedef unsigned long long ulonglong;
typedef long long longlong;
#endif /*__WIN__*/
#else
#include <my_global.h>
#include <my_sys.h>
#if defined(MYSQL_SERVER)
#include <m_string.h>
#else
/* when compiled as standalone */
#include <string.h>
#endif
#endif
#include <mysql.h>
#include <ctype.h>
#include <stdint.h>
#include <time.h>
#ifdef HAVE_DLOPEN
int randint(int n) {
//https://stackoverflow.com/a/822361/728236
if ((n - 1) == RAND_MAX) {
return rand();
} else {
// Chop off all of the values that would cause skew...
long end = RAND_MAX / n; // truncate skew
assert(end > 0L);
end *= n;
// ... and ignore results from rand() that fall above that limit.
// (Worst case the loop condition should succeed 50% of the time,
// so we can expect to bail out of this loop pretty quickly.)
int r;
while ((r = rand()) >= end);
return r % n;
}
}
my_bool bid_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
void bid_deinit(UDF_INIT *initid);
char *bid(UDF_INIT *initid __attribute__ ((unused)), UDF_ARGS *args, char *result, unsigned long *length, char *is_null, char *message __attribute__ ((unused)));
my_bool bid_init(UDF_INIT *initid, UDF_ARGS *args, char *message) {
initid->maybe_null = 0;
return 0;
}
char *bid(UDF_INIT *initid __attribute__ ((unused)), UDF_ARGS *args, char *result, unsigned long *length, char *is_null, char *message __attribute__ ((unused))) {
struct timespec ts;
unsigned char *bytes = malloc(sizeof (char) * (9));
timespec_get(&ts, TIME_UTC);
uint64_t Timestamp = ts.tv_sec * 1000000000 + ts.tv_nsec;
bytes[0] = (Timestamp >> 56) & 0xFF;
bytes[1] = (Timestamp >> 48) & 0xFF;
bytes[2] = (Timestamp >> 40) & 0xFF;
bytes[3] = (Timestamp >> 32) & 0xFF;
bytes[4] = (Timestamp >> 24) & 0xFF;
bytes[5] = (Timestamp >> 16) & 0xFF;
bytes[6] = (Timestamp >> 8) & 0xFF;
bytes[7] = Timestamp & 0xFF;
bytes[8] = randint(256) & 0xFF;
*length = 9;
return bytes;
}
#endif /* HAVE_DLOPEN */
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