udf_example.cpp
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上传日期:2022-05-23
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- /* Copyright (C) 2002 MySQL AB
- 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; either version 2 of the License, or
- (at your option) any later version.
- 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- /*
- ** example file of UDF (user definable functions) that are dynamicly loaded
- ** into the standard mysqld core.
- **
- ** The functions name, type and shared library is saved in the new system
- ** table 'func'. To be able to create new functions one must have write
- ** privilege for the database 'mysql'. If one starts MySQL with
- ** --skip-grant, then UDF initialization will also be skipped.
- **
- ** Syntax for the new commands are:
- ** create function <function_name> returns {string|real|integer}
- ** soname <name_of_shared_library>
- ** drop function <function_name>
- **
- ** Each defined function may have a xxxx_init function and a xxxx_deinit
- ** function. The init function should alloc memory for the function
- ** and tell the main function about the max length of the result
- ** (for string functions), number of decimals (for double functions) and
- ** if the result may be a null value.
- **
- ** If a function sets the 'error' argument to 1 the function will not be
- ** called anymore and mysqld will return NULL for all calls to this copy
- ** of the function.
- **
- ** All strings arguments to functions are given as string pointer + length
- ** to allow handling of binary data.
- ** Remember that all functions must be thread safe. This means that one is not
- ** allowed to alloc any global or static variables that changes!
- ** If one needs memory one should alloc this in the init function and free
- ** this on the __deinit function.
- **
- ** Note that the init and __deinit functions are only called once per
- ** SQL statement while the value function may be called many times
- **
- ** Function 'metaphon' returns a metaphon string of the string argument.
- ** This is something like a soundex string, but it's more tuned for English.
- **
- ** Function 'myfunc_double' returns summary of codes of all letters
- ** of arguments divided by summary length of all its arguments.
- **
- ** Function 'myfunc_int' returns summary length of all its arguments.
- **
- ** Function 'sequence' returns an sequence starting from a certain number
- **
- ** On the end is a couple of functions that converts hostnames to ip and
- ** vice versa.
- **
- ** A dynamicly loadable file should be compiled shared.
- ** (something like: gcc -shared -o my_func.so myfunc.cc).
- ** You can easily get all switches right by doing:
- ** cd sql ; make udf_example.o
- ** Take the compile line that make writes, remove the '-c' near the end of
- ** the line and add -shared -o udf_example.so to the end of the compile line.
- ** The resulting library (udf_example.so) should be copied to some dir
- ** searched by ld. (/usr/lib ?)
- ** If you are using gcc, then you should be able to create the udf_example.so
- ** by simply doing 'make udf_example.so'.
- **
- ** After the library is made one must notify mysqld about the new
- ** functions with the commands:
- **
- ** CREATE FUNCTION metaphon RETURNS STRING SONAME "udf_example.so";
- ** CREATE FUNCTION myfunc_double RETURNS REAL SONAME "udf_example.so";
- ** CREATE FUNCTION myfunc_int RETURNS INTEGER SONAME "udf_example.so";
- ** CREATE FUNCTION sequence RETURNS INTEGER SONAME "udf_example.so";
- ** CREATE FUNCTION lookup RETURNS STRING SONAME "udf_example.so";
- ** CREATE FUNCTION reverse_lookup RETURNS STRING SONAME "udf_example.so";
- ** CREATE AGGREGATE FUNCTION avgcost RETURNS REAL SONAME "udf_example.so";
- **
- ** After this the functions will work exactly like native MySQL functions.
- ** Functions should be created only once.
- **
- ** The functions can be deleted by:
- **
- ** DROP FUNCTION metaphon;
- ** DROP FUNCTION myfunc_double;
- ** DROP FUNCTION myfunc_int;
- ** DROP FUNCTION lookup;
- ** DROP FUNCTION reverse_lookup;
- ** DROP FUNCTION avgcost;
- **
- ** The CREATE FUNCTION and DROP FUNCTION update the func@mysql table. All
- ** Active function will be reloaded on every restart of server
- ** (if --skip-grant-tables is not given)
- **
- ** If you ge problems with undefined symbols when loading the shared
- ** library, you should verify that mysqld is compiled with the -rdynamic
- ** option.
- **
- ** If you can't get AGGREGATES to work, check that you have the column
- ** 'type' in the mysql.func table. If not, run 'mysql_fix_privilege_tables'.
- **
- */
- #ifdef STANDARD
- #include <stdio.h>
- #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>
- #endif
- #include <mysql.h>
- #include <m_ctype.h>
- #include <m_string.h> // To get strmov()
- static pthread_mutex_t LOCK_hostname;
- #ifdef HAVE_DLOPEN
- /* These must be right or mysqld will not find the symbol! */
- extern "C" {
- my_bool metaphon_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
- void metaphon_deinit(UDF_INIT *initid);
- char *metaphon(UDF_INIT *initid, UDF_ARGS *args, char *result,
- unsigned long *length, char *is_null, char *error);
- my_bool myfunc_double_init(UDF_INIT *, UDF_ARGS *args, char *message);
- double myfunc_double(UDF_INIT *initid, UDF_ARGS *args, char *is_null,
- char *error);
- longlong myfunc_int(UDF_INIT *initid, UDF_ARGS *args, char *is_null,
- char *error);
- my_bool sequence_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
- void sequence_deinit(UDF_INIT *initid);
- longlong sequence(UDF_INIT *initid, UDF_ARGS *args, char *is_null,
- char *error);
- my_bool avgcost_init( UDF_INIT* initid, UDF_ARGS* args, char* message );
- void avgcost_deinit( UDF_INIT* initid );
- void avgcost_reset( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
- void avgcost_clear( UDF_INIT* initid, char* is_null, char *error );
- void avgcost_add( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
- double avgcost( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char *error );
- }
- /*************************************************************************
- ** Example of init function
- ** Arguments:
- ** initid Points to a structure that the init function should fill.
- ** This argument is given to all other functions.
- ** my_bool maybe_null 1 if function can return NULL
- ** Default value is 1 if any of the arguments
- ** is declared maybe_null.
- ** unsigned int decimals Number of decimals.
- ** Default value is max decimals in any of the
- ** arguments.
- ** unsigned int max_length Length of string result.
- ** The default value for integer functions is 21
- ** The default value for real functions is 13+
- ** default number of decimals.
- ** The default value for string functions is
- ** the longest string argument.
- ** char *ptr; A pointer that the function can use.
- **
- ** args Points to a structure which contains:
- ** unsigned int arg_count Number of arguments
- ** enum Item_result *arg_type Types for each argument.
- ** Types are STRING_RESULT, REAL_RESULT
- ** and INT_RESULT.
- ** char **args Pointer to constant arguments.
- ** Contains 0 for not constant argument.
- ** unsigned long *lengths; max string length for each argument
- ** char *maybe_null Information of which arguments
- ** may be NULL
- **
- ** message Error message that should be passed to the user on fail.
- ** The message buffer is MYSQL_ERRMSG_SIZE big, but one should
- ** try to keep the error message less than 80 bytes long!
- **
- ** This function should return 1 if something goes wrong. In this case
- ** message should contain something usefull!
- **************************************************************************/
- #define MAXMETAPH 8
- my_bool metaphon_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
- {
- if (args->arg_count != 1 || args->arg_type[0] != STRING_RESULT)
- {
- strcpy(message,"Wrong arguments to metaphon; Use the source");
- return 1;
- }
- initid->max_length=MAXMETAPH;
- return 0;
- }
- /****************************************************************************
- ** Deinit function. This should free all resources allocated by
- ** this function.
- ** Arguments:
- ** initid Return value from xxxx_init
- ****************************************************************************/
- void metaphon_deinit(UDF_INIT *initid)
- {
- }
- /***************************************************************************
- ** UDF string function.
- ** Arguments:
- ** initid Structure filled by xxx_init
- ** args The same structure as to xxx_init. This structure
- ** contains values for all parameters.
- ** Note that the functions MUST check and convert all
- ** to the type it wants! Null values are represented by
- ** a NULL pointer
- ** result Possible buffer to save result. At least 255 byte long.
- ** length Pointer to length of the above buffer. In this the function
- ** should save the result length
- ** is_null If the result is null, one should store 1 here.
- ** error If something goes fatally wrong one should store 1 here.
- **
- ** This function should return a pointer to the result string.
- ** Normally this is 'result' but may also be an alloced string.
- ***************************************************************************/
- /* Character coding array */
- static char codes[26] = {
- 1,16,4,16,9,2,4,16,9,2,0,2,2,2,1,4,0,2,4,4,1,0,0,0,8,0
- /* A B C D E F G H I J K L M N O P Q R S T U V W X Y Z*/
- };
- /*--- Macros to access character coding array -------------*/
- #define ISVOWEL(x) (codes[(x) - 'A'] & 1) /* AEIOU */
- /* Following letters are not changed */
- #define NOCHANGE(x) (codes[(x) - 'A'] & 2) /* FJLMNR */
- /* These form diphthongs when preceding H */
- #define AFFECTH(x) (codes[(x) - 'A'] & 4) /* CGPST */
- /* These make C and G soft */
- #define MAKESOFT(x) (codes[(x) - 'A'] & 8) /* EIY */
- /* These prevent GH from becoming F */
- #define NOGHTOF(x) (codes[(x) - 'A'] & 16) /* BDH */
- char *metaphon(UDF_INIT *initid, UDF_ARGS *args, char *result,
- unsigned long *length, char *is_null, char *error)
- {
- const char *word=args->args[0];
- if (!word) // Null argument
- {
- *is_null=1;
- return 0;
- }
- const char *w_end=word+args->lengths[0];
- char *org_result=result;
- char *n, *n_start, *n_end; /* pointers to string */
- char *metaph, *metaph_end; /* pointers to metaph */
- char ntrans[32]; /* word with uppercase letters */
- char newm[8]; /* new metaph for comparison */
- int KSflag; /* state flag for X to KS */
- /*--------------------------------------------------------
- * Copy word to internal buffer, dropping non-alphabetic
- * characters and converting to uppercase.
- *-------------------------------------------------------*/
- for (n = ntrans + 1, n_end = ntrans + sizeof(ntrans)-2;
- word != w_end && n < n_end; word++ )
- if ( my_isalpha ( &my_charset_latin1, *word ))
- *n++ = my_toupper ( &my_charset_latin1, *word );
- if ( n == ntrans + 1 ) /* return empty string if 0 bytes */
- {
- *length=0;
- return result;
- }
- n_end = n; /* set n_end to end of string */
- ntrans[0] = 'Z'; /* ntrans[0] should be a neutral char */
- n[0]=n[1]=0; /* pad with nulls */
- n = ntrans + 1; /* assign pointer to start */
- /*------------------------------------------------------------
- * check for all prefixes:
- * PN KN GN AE WR WH and X at start.
- *----------------------------------------------------------*/
- switch ( *n ) {
- case 'P':
- case 'K':
- case 'G':
- if ( n[1] == 'N')
- *n++ = 0;
- break;
- case 'A':
- if ( n[1] == 'E')
- *n++ = 0;
- break;
- case 'W':
- if ( n[1] == 'R' )
- *n++ = 0;
- else
- if ( *(n + 1) == 'H')
- {
- n[1] = *n;
- *n++ = 0;
- }
- break;
- case 'X':
- *n = 'S';
- break;
- }
- /*------------------------------------------------------------
- * Now, loop step through string, stopping at end of string
- * or when the computed metaph is MAXMETAPH characters long
- *----------------------------------------------------------*/
- KSflag = 0; /* state flag for KS translation */
- for (metaph_end = result + MAXMETAPH, n_start = n;
- n <= n_end && result < metaph_end; n++ )
- {
- if ( KSflag )
- {
- KSflag = 0;
- *result++ = *n;
- }
- else
- {
- /* drop duplicates except for CC */
- if ( *( n - 1 ) == *n && *n != 'C' )
- continue;
- /* check for F J L M N R or first letter vowel */
- if ( NOCHANGE ( *n ) ||
- ( n == n_start && ISVOWEL ( *n )))
- *result++ = *n;
- else
- switch ( *n ) {
- case 'B': /* check for -MB */
- if ( n < n_end || *( n - 1 ) != 'M' )
- *result++ = *n;
- break;
- case 'C': /* C = X ("sh" sound) in CH and CIA */
- /* = S in CE CI and CY */
- /* dropped in SCI SCE SCY */
- /* else K */
- if ( *( n - 1 ) != 'S' ||
- !MAKESOFT ( n[1]))
- {
- if ( n[1] == 'I' && n[2] == 'A' )
- *result++ = 'X';
- else
- if ( MAKESOFT ( n[1]))
- *result++ = 'S';
- else
- if ( n[1] == 'H' )
- *result++ = (( n == n_start &&
- !ISVOWEL ( n[2])) ||
- *( n - 1 ) == 'S' ) ?
- (char)'K' : (char)'X';
- else
- *result++ = 'K';
- }
- break;
- case 'D': /* J before DGE, DGI, DGY, else T */
- *result++ =
- ( n[1] == 'G' &&
- MAKESOFT ( n[2])) ?
- (char)'J' : (char)'T';
- break;
- case 'G': /* complicated, see table in text */
- if (( n[1] != 'H' || ISVOWEL ( n[2]))
- && (
- n[1] != 'N' ||
- (
- (n + 1) < n_end &&
- (
- n[2] != 'E' ||
- *( n + 3 ) != 'D'
- )
- )
- )
- && (
- *( n - 1 ) != 'D' ||
- !MAKESOFT ( n[1])
- )
- )
- *result++ =
- ( MAKESOFT ( *( n + 1 )) &&
- n[2] != 'G' ) ?
- (char)'J' : (char)'K';
- else
- if ( n[1] == 'H' &&
- !NOGHTOF( *( n - 3 )) &&
- *( n - 4 ) != 'H')
- *result++ = 'F';
- break;
- case 'H': /* H if before a vowel and not after */
- /* C, G, P, S, T */
- if ( !AFFECTH ( *( n - 1 )) &&
- ( !ISVOWEL ( *( n - 1 )) ||
- ISVOWEL ( n[1])))
- *result++ = 'H';
- break;
- case 'K': /* K = K, except dropped after C */
- if ( *( n - 1 ) != 'C')
- *result++ = 'K';
- break;
- case 'P': /* PH = F, else P = P */
- *result++ = *( n + 1 ) == 'H'
- ? (char)'F' : (char)'P';
- break;
- case 'Q': /* Q = K (U after Q is already gone */
- *result++ = 'K';
- break;
- case 'S': /* SH, SIO, SIA = X ("sh" sound) */
- *result++ = ( n[1] == 'H' ||
- ( *(n + 1) == 'I' &&
- ( n[2] == 'O' ||
- n[2] == 'A'))) ?
- (char)'X' : (char)'S';
- break;
- case 'T': /* TIO, TIA = X ("sh" sound) */
- /* TH = 0, ("th" sound ) */
- if ( *( n + 1 ) == 'I' && ( n[2] == 'O'
- || n[2] == 'A') )
- *result++ = 'X';
- else
- if ( n[1] == 'H' )
- *result++ = '0';
- else
- if ( *( n + 1) != 'C' || n[2] != 'H')
- *result++ = 'T';
- break;
- case 'V': /* V = F */
- *result++ = 'F';
- break;
- case 'W': /* only exist if a vowel follows */
- case 'Y':
- if ( ISVOWEL ( n[1]))
- *result++ = *n;
- break;
- case 'X': /* X = KS, except at start */
- if ( n == n_start )
- *result++ = 'S';
- else
- {
- *result++ = 'K'; /* insert K, then S */
- KSflag = 1; /* this flag will cause S to be
- inserted on next pass thru loop */
- }
- break;
- case 'Z':
- *result++ = 'S';
- break;
- }
- }
- }
- *length= (ulong) (result - org_result);
- return org_result;
- }
- /***************************************************************************
- ** UDF double function.
- ** Arguments:
- ** initid Structure filled by xxx_init
- ** args The same structure as to xxx_init. This structure
- ** contains values for all parameters.
- ** Note that the functions MUST check and convert all
- ** to the type it wants! Null values are represented by
- ** a NULL pointer
- ** is_null If the result is null, one should store 1 here.
- ** error If something goes fatally wrong one should store 1 here.
- **
- ** This function should return the result.
- ***************************************************************************/
- my_bool myfunc_double_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
- {
- if (!args->arg_count)
- {
- strcpy(message,"myfunc_double must have at least on argument");
- return 1;
- }
- /*
- ** As this function wants to have everything as strings, force all arguments
- ** to strings.
- */
- for (uint i=0 ; i < args->arg_count; i++)
- args->arg_type[i]=STRING_RESULT;
- initid->maybe_null=1; // The result may be null
- initid->decimals=2; // We want 2 decimals in the result
- initid->max_length=6; // 3 digits + . + 2 decimals
- return 0;
- }
- double myfunc_double(UDF_INIT *initid, UDF_ARGS *args, char *is_null,
- char *error)
- {
- unsigned long val = 0;
- unsigned long v = 0;
- for (uint i = 0; i < args->arg_count; i++)
- {
- if (args->args[i] == NULL)
- continue;
- val += args->lengths[i];
- for (uint j=args->lengths[i] ; j-- > 0 ;)
- v += args->args[i][j];
- }
- if (val)
- return (double) v/ (double) val;
- *is_null=1;
- return 0.0;
- }
- /***************************************************************************
- ** UDF long long function.
- ** Arguments:
- ** initid Return value from xxxx_init
- ** args The same structure as to xxx_init. This structure
- ** contains values for all parameters.
- ** Note that the functions MUST check and convert all
- ** to the type it wants! Null values are represented by
- ** a NULL pointer
- ** is_null If the result is null, one should store 1 here.
- ** error If something goes fatally wrong one should store 1 here.
- **
- ** This function should return the result as a long long
- ***************************************************************************/
- /* This function returns the sum of all arguments */
- longlong myfunc_int(UDF_INIT *initid, UDF_ARGS *args, char *is_null,
- char *error)
- {
- longlong val = 0;
- for (uint i = 0; i < args->arg_count; i++)
- {
- if (args->args[i] == NULL)
- continue;
- switch (args->arg_type[i]) {
- case STRING_RESULT: // Add string lengths
- val += args->lengths[i];
- break;
- case INT_RESULT: // Add numbers
- val += *((longlong*) args->args[i]);
- break;
- case REAL_RESULT: // Add numers as longlong
- val += (longlong) *((double*) args->args[i]);
- break;
- default:
- break;
- }
- }
- return val;
- }
- /*
- Simple example of how to get a sequences starting from the first argument
- or 1 if no arguments have been given
- */
- my_bool sequence_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
- {
- if (args->arg_count > 1)
- {
- strmov(message,"This function takes none or 1 argument");
- return 1;
- }
- if (args->arg_count)
- args->arg_type[0]= INT_RESULT; // Force argument to int
- if (!(initid->ptr=(char*) malloc(sizeof(longlong))))
- {
- strmov(message,"Couldn't allocate memory");
- return 1;
- }
- bzero(initid->ptr,sizeof(longlong));
- /*
- Fool MySQL to think that this function is a constant
- This will ensure that MySQL only evalutes the function
- when the rows are sent to the client and not before any ORDER BY
- clauses
- */
- initid->const_item=1;
- return 0;
- }
- void sequence_deinit(UDF_INIT *initid)
- {
- if (initid->ptr)
- free(initid->ptr);
- }
- longlong sequence(UDF_INIT *initid, UDF_ARGS *args, char *is_null,
- char *error)
- {
- ulonglong val=0;
- if (args->arg_count)
- val= *((longlong*) args->args[0]);
- return ++*((longlong*) initid->ptr) + val;
- }
- /****************************************************************************
- ** Some functions that handles IP and hostname conversions
- ** The orignal function was from Zeev Suraski.
- **
- ** CREATE FUNCTION lookup RETURNS STRING SONAME "udf_example.so";
- ** CREATE FUNCTION reverse_lookup RETURNS STRING SONAME "udf_example.so";
- **
- ****************************************************************************/
- #include <sys/socket.h>
- #include <netinet/in.h>
- #include <arpa/inet.h>
- #include <netdb.h>
- extern "C" {
- my_bool lookup_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
- void lookup_deinit(UDF_INIT *initid);
- char *lookup(UDF_INIT *initid, UDF_ARGS *args, char *result,
- unsigned long *length, char *null_value, char *error);
- my_bool reverse_lookup_init(UDF_INIT *initid, UDF_ARGS *args, char *message);
- void reverse_lookup_deinit(UDF_INIT *initid);
- char *reverse_lookup(UDF_INIT *initid, UDF_ARGS *args, char *result,
- unsigned long *length, char *null_value, char *error);
- }
- /****************************************************************************
- ** lookup IP for an hostname.
- **
- ** This code assumes that gethostbyname_r exists and inet_ntoa() is thread
- ** safe (As it is in Solaris)
- ****************************************************************************/
- my_bool lookup_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
- {
- if (args->arg_count != 1 || args->arg_type[0] != STRING_RESULT)
- {
- strmov(message,"Wrong arguments to lookup; Use the source");
- return 1;
- }
- initid->max_length=11;
- initid->maybe_null=1;
- #if !defined(HAVE_GETHOSTBYADDR_R) || !defined(HAVE_SOLARIS_STYLE_GETHOST)
- (void) pthread_mutex_init(&LOCK_hostname,MY_MUTEX_INIT_SLOW);
- #endif
- return 0;
- }
- void lookup_deinit(UDF_INIT *initid)
- {
- #if !defined(HAVE_GETHOSTBYADDR_R) || !defined(HAVE_SOLARIS_STYLE_GETHOST)
- (void) pthread_mutex_destroy(&LOCK_hostname);
- #endif
- }
- char *lookup(UDF_INIT *initid, UDF_ARGS *args, char *result,
- unsigned long *res_length, char *null_value, char *error)
- {
- uint length;
- int tmp_errno;
- char name_buff[256],hostname_buff[2048];
- struct hostent tmp_hostent,*hostent;
- if (!args->args[0] || !(length=args->lengths[0]))
- {
- *null_value=1;
- return 0;
- }
- if (length >= sizeof(name_buff))
- length=sizeof(name_buff)-1;
- memcpy(name_buff,args->args[0],length);
- name_buff[length]=0;
- #if defined(HAVE_GETHOSTBYADDR_R) && defined(HAVE_SOLARIS_STYLE_GETHOST)
- if (!(hostent=gethostbyname_r(name_buff,&tmp_hostent,hostname_buff,
- sizeof(hostname_buff), &tmp_errno)))
- {
- *null_value=1;
- return 0;
- }
- #else
- VOID(pthread_mutex_lock(&LOCK_hostname));
- if (!(hostent= gethostbyname((char*) name_buff)))
- {
- VOID(pthread_mutex_unlock(&LOCK_hostname));
- *null_value= 1;
- return 0;
- }
- VOID(pthread_mutex_unlock(&LOCK_hostname));
- #endif
- struct in_addr in;
- memcpy_fixed((char*) &in,(char*) *hostent->h_addr_list, sizeof(in.s_addr));
- *res_length= (ulong) (strmov(result, inet_ntoa(in)) - result);
- return result;
- }
- /****************************************************************************
- ** return hostname for an IP number.
- ** The functions can take as arguments a string "xxx.xxx.xxx.xxx" or
- ** four numbers.
- ****************************************************************************/
- my_bool reverse_lookup_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
- {
- if (args->arg_count == 1)
- args->arg_type[0]= STRING_RESULT;
- else if (args->arg_count == 4)
- args->arg_type[0]=args->arg_type[1]=args->arg_type[2]=args->arg_type[3]=
- INT_RESULT;
- else
- {
- strmov(message,
- "Wrong number of arguments to reverse_lookup; Use the source");
- return 1;
- }
- initid->max_length=32;
- initid->maybe_null=1;
- #if !defined(HAVE_GETHOSTBYADDR_R) || !defined(HAVE_SOLARIS_STYLE_GETHOST)
- (void) pthread_mutex_init(&LOCK_hostname,MY_MUTEX_INIT_SLOW);
- #endif
- return 0;
- }
- void reverse_lookup_deinit(UDF_INIT *initid)
- {
- #if !defined(HAVE_GETHOSTBYADDR_R) || !defined(HAVE_SOLARIS_STYLE_GETHOST)
- (void) pthread_mutex_destroy(&LOCK_hostname);
- #endif
- }
- char *reverse_lookup(UDF_INIT *initid, UDF_ARGS *args, char *result,
- unsigned long *res_length, char *null_value, char *error)
- {
- char name_buff[256];
- struct hostent tmp_hostent;
- uint length;
- if (args->arg_count == 4)
- {
- if (!args->args[0] || !args->args[1] ||!args->args[2] ||!args->args[3])
- {
- *null_value=1;
- return 0;
- }
- sprintf(result,"%d.%d.%d.%d",
- (int) *((longlong*) args->args[0]),
- (int) *((longlong*) args->args[1]),
- (int) *((longlong*) args->args[2]),
- (int) *((longlong*) args->args[3]));
- }
- else
- { // string argument
- if (!args->args[0]) // Return NULL for NULL values
- {
- *null_value=1;
- return 0;
- }
- length=args->lengths[0];
- if (length >= (uint) *res_length-1)
- length=(uint) *res_length;
- memcpy(result,args->args[0],length);
- result[length]=0;
- }
- unsigned long taddr = inet_addr(result);
- if (taddr == (unsigned long) -1L)
- {
- *null_value=1;
- return 0;
- }
- struct hostent *hp;
- #if defined(HAVE_GETHOSTBYADDR_R) && defined(HAVE_SOLARIS_STYLE_GETHOST)
- int tmp_errno;
- if (!(hp=gethostbyaddr_r((char*) &taddr,sizeof(taddr), AF_INET,
- &tmp_hostent, name_buff,sizeof(name_buff),
- &tmp_errno)))
- {
- *null_value=1;
- return 0;
- }
- #else
- VOID(pthread_mutex_lock(&LOCK_hostname));
- if (!(hp= gethostbyaddr((char*) &taddr, sizeof(taddr), AF_INET)))
- {
- VOID(pthread_mutex_unlock(&LOCK_hostname));
- *null_value= 1;
- return 0;
- }
- VOID(pthread_mutex_unlock(&LOCK_hostname));
- #endif
- *res_length=(ulong) (strmov(result,hp->h_name) - result);
- return result;
- }
- /*
- ** Syntax for the new aggregate commands are:
- ** create aggregate function <function_name> returns {string|real|integer}
- ** soname <name_of_shared_library>
- **
- ** Syntax for avgcost: avgcost( t.quantity, t.price )
- ** with t.quantity=integer, t.price=double
- ** (this example is provided by Andreas F. Bobak <bobak@relog.ch>)
- */
- struct avgcost_data
- {
- ulonglong count;
- longlong totalquantity;
- double totalprice;
- };
- /*
- ** Average Cost Aggregate Function.
- */
- my_bool
- avgcost_init( UDF_INIT* initid, UDF_ARGS* args, char* message )
- {
- struct avgcost_data* data;
- if (args->arg_count != 2)
- {
- strcpy(
- message,
- "wrong number of arguments: AVGCOST() requires two arguments"
- );
- return 1;
- }
- if ((args->arg_type[0] != INT_RESULT) || (args->arg_type[1] != REAL_RESULT) )
- {
- strcpy(
- message,
- "wrong argument type: AVGCOST() requires an INT and a REAL"
- );
- return 1;
- }
- /*
- ** force arguments to double.
- */
- /*args->arg_type[0] = REAL_RESULT;
- args->arg_type[1] = REAL_RESULT;*/
- initid->maybe_null = 0; // The result may be null
- initid->decimals = 4; // We want 4 decimals in the result
- initid->max_length = 20; // 6 digits + . + 10 decimals
- data = new struct avgcost_data;
- data->totalquantity = 0;
- data->totalprice = 0.0;
- initid->ptr = (char*)data;
- return 0;
- }
- void
- avgcost_deinit( UDF_INIT* initid )
- {
- delete initid->ptr;
- }
- /* This is only for MySQL 4.0 compability */
- void
- avgcost_reset(UDF_INIT* initid, UDF_ARGS* args, char* is_null, char* message)
- {
- avgcost_clear(initid, is_null, message);
- avgcost_add(initid, args, is_null, message);
- }
- /* This is needed to get things to work in MySQL 4.1.1 and above */
- void
- avgcost_clear(UDF_INIT* initid, char* is_null, char* message)
- {
- struct avgcost_data* data = (struct avgcost_data*)initid->ptr;
- data->totalprice= 0.0;
- data->totalquantity= 0;
- data->count= 0;
- }
- void
- avgcost_add(UDF_INIT* initid, UDF_ARGS* args, char* is_null, char* message)
- {
- if (args->args[0] && args->args[1])
- {
- struct avgcost_data* data = (struct avgcost_data*)initid->ptr;
- longlong quantity = *((longlong*)args->args[0]);
- longlong newquantity = data->totalquantity + quantity;
- double price = *((double*)args->args[1]);
- data->count++;
- if ( ((data->totalquantity >= 0) && (quantity < 0))
- || ((data->totalquantity < 0) && (quantity > 0)) )
- {
- /*
- ** passing from + to - or from - to +
- */
- if ( ((quantity < 0) && (newquantity < 0))
- || ((quantity > 0) && (newquantity > 0)) )
- {
- data->totalprice = price * double(newquantity);
- }
- /*
- ** sub q if totalq > 0
- ** add q if totalq < 0
- */
- else
- {
- price = data->totalprice / double(data->totalquantity);
- data->totalprice = price * double(newquantity);
- }
- data->totalquantity = newquantity;
- }
- else
- {
- data->totalquantity += quantity;
- data->totalprice += price * double(quantity);
- }
- if (data->totalquantity == 0)
- data->totalprice = 0.0;
- }
- }
- double
- avgcost( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char* error )
- {
- struct avgcost_data* data = (struct avgcost_data*)initid->ptr;
- if (!data->count || !data->totalquantity)
- {
- *is_null = 1;
- return 0.0;
- }
- *is_null = 0;
- return data->totalprice/double(data->totalquantity);
- }
- #endif /* HAVE_DLOPEN */