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Revise the API for user-defined functions. (CVS 398)

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FossilOrigin-Name: 633951f0fa11c91f93aa2862df84691750c01e73
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drh
2002-02-27 19:00:20 +00:00
parent 4e0f995347
commit 1350b030c1
10 changed files with 331 additions and 146 deletions
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76
src/sqlite.h.in
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@@ -12,7 +12,7 @@
** This header file defines the interface that the SQLite library
** presents to client programs.
**
** @(#) $Id: sqlite.h.in,v 1.26 2002/02/23 23:45:45 drh Exp $
** @(#) $Id: sqlite.h.in,v 1.27 2002/02/27 19:00:22 drh Exp $
*/
#ifndef _SQLITE_H_
#define _SQLITE_H_
@@ -362,40 +362,80 @@ int sqlite_get_table_vprintf(
va_list ap /* Arguments to the format string */
);
/*
** A pointer to the following structure is used to communicate with
** the implementations of user-defined functions.
*/
typedef struct sqlite_func sqlite_func;
/*
** Use the following routines to create new user-defined functions. See
** the documentation for details.
*/
int sqlite_create_function(
sqlite*, /* Database where the new function is registered */
const char *zName, /* Name of the new function */
int nArg, /* Number of arguments. -1 means any number */
void (*xFunc)(void*,int,const char**) /* C code to implement the function */
sqlite*, /* Database where the new function is registered */
const char *zName, /* Name of the new function */
int nArg, /* Number of arguments. -1 means any number */
void (*xFunc)(sqlite_func*,int,const char**), /* C code to implement */
void *pUserData /* Available via the sqlite_user_data() call */
);
int sqlite_create_aggregate(
sqlite*, /* Database where the new function is registered */
const char *zName, /* Name of the function */
int nArg, /* Number of arguments */
void *(*xStep)(void*,int,const char**), /* Called for each row */
void (*xFinalize)(void*,void*) /* Called once to get final result */
sqlite*, /* Database where the new function is registered */
const char *zName, /* Name of the function */
int nArg, /* Number of arguments */
void (*xStep)(sqlite_func*,int,const char**), /* Called for each row */
void (*xFinalize)(sqlite_func*), /* Called once to get final result */
void *pUserData /* Available via the sqlite_user_data() call */
);
/*
** The user function implementations call one of the following four routines
** in order to return their results. The first parameter to each of these
** routines is a copy of the first argument to xFunc() or the second argument
** to xFinalize(). The second parameter to these routines is the result
** to be returned. A NULL can be passed as the second parameter to
** sqlite_set_result_string() in order to return a NULL result.
** routines is a copy of the first argument to xFunc() or xFinialize()
** The second parameter to these routines is the result to be returned.
** A NULL can be passed as the second parameter to sqlite_set_result_string()
** in order to return a NULL result.
**
** The 3rd argument to _string and _error is the number of characters to
** take from the string. If this argument is negative, then all characters
** up to and including the first '\000' are used.
**
** The sqlite_set_result_string() function allocates a buffer to hold the
** result and returns a pointer to this buffer. The calling routine
** (that is, the implmentation of a user function) can alter the content
** of this buffer if desired.
*/
char *sqlite_set_result_string(void*,const char*,int);
void sqlite_set_result_int(void*,int);
void sqlite_set_result_double(void*,double);
void sqlite_set_result_error(void*,const char*,int);
char *sqlite_set_result_string(sqlite_func*,const char*,int);
void sqlite_set_result_int(sqlite_func*,int);
void sqlite_set_result_double(sqlite_func*,double);
void sqlite_set_result_error(sqlite_func*,const char*,int);
/*
** The pUserData parameter to the sqlite_create_function() and
** sqlite_create_aggregate() routines used to register user functions
** is available to the implementation of the function using this
** call.
*/
void *sqlite_user_data(sqlite_func*);
/*
** User aggregate functions use the following routine to allocate
** a structure for storing their context. The first time this routine
** is called for a particular aggregate, a new structure of size nBytes
** is allocated, zeroed, and returned. On subsequent calls (for the
** same aggregate instance) the same buffer is returned. The implementation
** of the aggregate can use the returned buffer to accumulate data.
**
** The buffer allocated is freed automatically be SQLite.
*/
void *sqlite_aggregate_context(sqlite_func*, int nBytes);
/*
** The next return returns the number of calls to xStep for a particular
** aggregate function instance. The current call to xStep counts so the
** function always returns at least 1.
*/
int sqlite_aggregate_count(sqlite_func*);
#ifdef __cplusplus
} /* End of the 'extern "C"' block */