//
// $Id$
//

//
// Sphinx UDF function example
//
// Linux
// gcc -fPIC -shared -o udfexample.so udfexample.c
// CREATE FUNCTION sequence RETURNS INT SONAME 'udfexample.so';
// CREATE FUNCTION strtoint RETURNS INT SONAME 'udfexample.so';
// CREATE FUNCTION avgmva RETURNS FLOAT SONAME 'udfexample.so';
//
// Windows
// cl /MTd /LD udfexample.c
// CREATE FUNCTION sequence RETURNS INT SONAME 'udfexample.dll';
// CREATE FUNCTION strtoint RETURNS INT SONAME 'udfexample.dll';
// CREATE FUNCTION avgmva RETURNS FLOAT SONAME 'udfexample.dll';
//

#include "sphinxudf.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#ifdef _MSC_VER
#define snprintf _snprintf
#define DLLEXPORT __declspec(dllexport)
#else
#define DLLEXPORT
#endif

/// UDF initialization
/// gets called on every query, when query begins
/// args are filled with values for a particular query
DLLEXPORT int sequence_init ( SPH_UDF_INIT * init, SPH_UDF_ARGS * args, char * error_message )
{
	// check argument count
	if ( args->arg_count > 1 )
	{
		snprintf ( error_message, SPH_UDF_ERROR_LEN, "SEQUENCE() takes either 0 or 1 arguments" );
		return 1;
	}

	// check argument type
	if ( args->arg_count && args->arg_types[0]!=SPH_UDF_TYPE_UINT32 )
    {
		snprintf ( error_message, SPH_UDF_ERROR_LEN, "SEQUENCE() requires 1st argument to be uint" );
		return 1;
	}

	// allocate and init counter storage
	init->func_data = (void*) malloc ( sizeof(int) );
	if ( !init->func_data )
	{
		snprintf ( error_message, SPH_UDF_ERROR_LEN, "malloc() failed" );
		return 1;
	}
	*(int*)init->func_data = 1;

	// all done
	return 0;
}


/// UDF deinitialization
/// gets called on every query, when query ends
DLLEXPORT void sequence_deinit ( SPH_UDF_INIT * init )
{
	// deallocate storage
	if ( init->func_data )
	{
		free ( init->func_data );
		init->func_data = NULL;
	}
}


/// UDF implementation
/// gets called for every row, unless optimized away
DLLEXPORT sphinx_int64_t sequence ( SPH_UDF_INIT * init, SPH_UDF_ARGS * args, char * error_flag )
{
	int res = (*(int*)init->func_data)++;
	if ( args->arg_count )
		res += *(int*)args->arg_values[0];
	return res;
}

//////////////////////////////////////////////////////////////////////////

DLLEXPORT int strtoint_init ( SPH_UDF_INIT * init, SPH_UDF_ARGS * args, char * error_message )
{
	if ( args->arg_count!=1 || args->arg_types[0]!=SPH_UDF_TYPE_STRING )
	{
		snprintf ( error_message, SPH_UDF_ERROR_LEN, "STRTOINT() requires 1 string argument" );
		return 1;
	}
	return 0;
}

DLLEXPORT sphinx_int64_t strtoint ( SPH_UDF_INIT * init, SPH_UDF_ARGS * args, char * error_flag )
{
	const char * s = args->arg_values[0];
	int len = args->str_lengths[0], res = 0;

	while ( len>0 && *s>='0' && *s<='9' )
	{
		res += *s - '0';
		len--;
	}

	return res;
}

//////////////////////////////////////////////////////////////////////////

DLLEXPORT int avgmva_init ( SPH_UDF_INIT * init, SPH_UDF_ARGS * args, char * error_message )
{
	if ( args->arg_count!=1 || args->arg_types[0]!=SPH_UDF_TYPE_UINT32SET )
	{
		snprintf ( error_message, SPH_UDF_ERROR_LEN, "STRTOINT() requires 1 MVA argument" );
		return 1;
	}
	return 0;
}

DLLEXPORT double avgmva ( SPH_UDF_INIT * init, SPH_UDF_ARGS * args, char * error_flag )
{
	unsigned int * mva = (unsigned int *) args->arg_values[0];
	double res = 0;
	int i, n;

	if ( !mva )
		return res;

	n = *mva++;
	for ( i=0; i<n; i++, mva++ )
		res += *mva;

	return res/n;
}

//
// $Id$
//