/* 
	lib_mysqludf_str - string functions
	Copyright (C) 2007  Roland Bouman 
	web: http://www.xcdsql.org/MySQL/UDF/ 
	email: mysqludfs@gmail.com

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.
	
	This library 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
	Lesser General Public License for more details.
	
	You should have received a copy of the GNU Lesser General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
	
*/

#if defined(_WIN32) || defined(_WIN64) || defined(__WIN32__) || defined(WIN32)
#define DLLEXP __declspec(dllexport) 
#else
#define DLLEXP
#endif

#ifdef STANDARD
#include <string.h>
#include <stdlib.h>
#include <time.h>
#ifdef __WIN__
typedef unsigned __int64 ulonglong;
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>
#include <stdlib.h>

#include <ctype.h>

#ifdef HAVE_DLOPEN

#define LIBVERSION "lib_mysqludf_str version 0.0.1"

#ifdef	__cplusplus
extern "C" {
#endif

/**
 * lib_mysqludf_statistics_info
 */
DLLEXP 
my_bool lib_mysqludf_str_info_init(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *message
);

DLLEXP 
void lib_mysqludf_str_info_deinit(
	UDF_INIT *initid
);

DLLEXP 
char* lib_mysqludf_str_info(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char* result
,	unsigned long* length
,	char *is_null
,	char *error
);

/**
 * lib_mysqludf_str_agg
 */
DLLEXP 
my_bool str_agg_init(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *message
);

DLLEXP 
void str_agg_deinit(
	UDF_INIT *initid
);

DLLEXP 
char* str_agg(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *result
,	unsigned long *length
,	char *is_null
,	char *error
);

DLLEXP 
char* str_agg_reset(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *is_null
,	char *error
);

DLLEXP 
char* str_agg_clear(
	UDF_INIT *initid
,	char *is_null
,	char *error
);

DLLEXP 
char* str_agg_add(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *is_null
,	char *error
);

#ifdef	__cplusplus
}
#endif

/**
 * lib_mysqludf_stat_info
 */
my_bool lib_mysqludf_str_info_init(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *message
){
	my_bool status;
	if(args->arg_count!=0){
		strcpy(
			message
		,	"No arguments allowed (udf: lib_mysqludf_str_info)"
		);
		status = 1;
	} else {
		status = 0;
	}
	initid->const_item = 1;
	return status;
}
void lib_mysqludf_str_info_deinit(
	UDF_INIT *initid
){
	//intentionally empty
}
char* lib_mysqludf_str_info(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char* result
,	unsigned long* length
,	char *is_null
,	char *error
){
	strcpy(result,LIBVERSION);
	*length = strlen(LIBVERSION);
	return result;
}

/**
 * lib_mysqludf_str_agg
 */
typedef struct st_str_agg {
	unsigned long chunk_length;			//the allocation unit
	unsigned long result_length;		//the length of the contents in the buffer
	unsigned long result_max_length;	//the length of the buffer
	char * result;						//the buffer
} STR_AGG;


my_bool str_agg_init(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *message
){
	int unsigned i;
	if(args->arg_count==0){
		strcpy(
			message
		,	"Expected one or more string arguments (udf: lib_mysqludf_str_agg)"
		);
		return 1;
	} 
	if((initid->ptr = malloc(65535))==NULL){
		strcpy(
			message
		,	"Could not allocate memory (udf: str_agg_init)"
		);
		return 1;
	}
	initid->max_length = 65535 - sizeof(unsigned long) + 1;
	for (i=0; i<args->arg_count; i++){
		args->arg_type[i] = STRING_RESULT;
	}
	return 0;
}
void str_agg_deinit(
	UDF_INIT *initid
){
	if(initid->ptr!=NULL){
		free(initid->ptr);
	}
}
char* str_agg_reset(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *is_null
,	char *error
){
	str_agg_clear(
		initid
	,	is_null
	,	error
	);
	str_agg_add(
		initid
	,	args
	,	is_null
	,	error
	);
	return NULL;	//I hope this is what should be returned...
}
char* str_agg_clear(
	UDF_INIT *initid
,	char *is_null
,	char *error
){		
	*initid->ptr = (char)0;
	unsigned long *result_length_ptr = (unsigned long*)(initid->ptr+1);
	*result_length_ptr = 0;
	return NULL;
}
char* str_agg_add(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *is_null
,	char *error
){
	if(*initid->ptr==0){
		unsigned long *result_length_ptr = (unsigned long*)(initid->ptr + 1);
		char * buffer = initid->ptr + 1 + sizeof(unsigned long) + *result_length_ptr;
		int unsigned i;	
		unsigned long arg_length;
		for(i=0
		;	i<args->arg_count
		;	i++
		){
			arg_length = args->lengths[i];
			if((*result_length_ptr += arg_length)<initid->max_length){
				memcpy(buffer,args->args[i],arg_length);
				buffer += arg_length;
			} else {
				*initid->ptr = (char)1;
				*result_length_ptr -= arg_length;
			}
		}
	}
	return NULL;
}

char* str_agg(
	UDF_INIT *initid
,	UDF_ARGS *args
,	char *result
,	unsigned long *length
,	char *is_null
,	char *error
){
	*length = *((unsigned long*)(initid->ptr+1));	 
	return initid->ptr + 1 + sizeof(unsigned long); 
}

#endif /* HAVE_DLOPEN */