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kamailio/lib/srdb1/db_res.h

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/*
* Copyright (C) 2001-2003 FhG Fokus
* Copyright (C) 2007-2008 1&1 Internet AG
*
* This file is part of Kamailio, a free SIP server.
*
* Kamailio 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
*
* Kamailio 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
*/
/**
* \file lib/srdb1/db_res.h
* \brief Data structure that represents a result from a query.
*
* Data structure that represents a result from a database query,
* it also provides some convenience macros and some memory management
* functions for result structures.
* \ingroup db1
*/
#ifndef DB1_RES_H
#define DB1_RES_H
#include "db_key.h"
#include "db_val.h"
struct db_row;
/**
* This type represents a result returned by db_query function (see below). The
* result can consist of zero or more rows (see db_row_t description).
*
* Note: A variable of type db1_res_t returned by db_query function uses dynamicaly
* allocated memory, don't forget to call db_free_result if you don't need the
* variable anymore. You will encounter memory leaks if you fail to do this!
*
* In addition to zero or more rows, each db1_res_t object contains also an array
* of db_key_t objects. The objects represent keys (names of columns). *
*/
typedef struct db1_res {
struct {
db_key_t* names; /**< Column names */
db_type_t* types; /**< Column types */
int n; /**< Number of columns */
} col;
struct db_row* rows; /**< Rows */
int n; /**< Number of rows in current fetch */
int res_rows; /**< Number of total rows in query */
int last_row; /**< Last row */
void* ptr; /**< For use by DB modules */
} db1_res_t;
/** Return the column names */
#define RES_NAMES(re) ((re)->col.names)
/** Return the column types */
#define RES_TYPES(re) ((re)->col.types)
/** Return the number of columns */
#define RES_COL_N(re) ((re)->col.n)
/** Return the result rows */
#define RES_ROWS(re) ((re)->rows)
/** Return the number of current result rows */
#define RES_ROW_N(re) ((re)->n)
/** Return the last row of the result */
#define RES_LAST_ROW(re) ((re)->last_row)
/** Return the number of total result rows */
#define RES_NUM_ROWS(re) ((re)->res_rows)
/** Return the module-specific pointer */
#define RES_PTR(re) ((re)->ptr)
/**
* Release memory used by rows in a result structure.
* \param _r the result that should be released
* \return zero on success, negative on errors
*/
int db_free_rows(db1_res_t* _r);
/**
* Release memory used by columns. This methods assumes that the string values
* holding the column names are in memory allocated from the database driver,
* and thus must be not freed here.
* \param _r the result that should be released
* \return zero on success, negative on errors
*/
int db_free_columns(db1_res_t* _r);
/**
* Create a new result structure and initialize it.
* \return a pointer to the new result on success, NULL on errors
*/
db1_res_t* db_new_result(void);
/**
* Release memory used by a result structure.
* \return zero on success, negative on errors
*/
int db_free_result(db1_res_t* _r);
/**
* Allocate storage for column names and type in existing result structure.
* If no more memory is available for the allocation of the types then the
* already allocated memory for the names is freed.
* \param _r filled result set
* \param cols number of columns
* \return zero on success, negative on errors
*/
int db_allocate_columns(db1_res_t* _r, const unsigned int cols);
/**
* Allocate memory for rows.
* \param _res result set
* \return zero on success, negative on errors
*/
int db_allocate_rows(db1_res_t* _res);
/**
* Reallocate memory for rows.
* \param _res result set
* \param _nsize new number of rows in result set
* \return zero on success, negative on errors
*/
int db_reallocate_rows(db1_res_t* _res, int _nsize);
#endif /* DB1_RES_H */