/**
* Copyright 2005-2007 ECMWF
*
* Licensed under the GNU Lesser General Public License which
* incorporates the terms and conditions of version 3 of the GNU
* General Public License.
* See LICENSE and gpl-3.0.txt for details.
*/

/**********************************
 *  Enrico Fucile
 **********************************/

#include "grib_api_internal.h"
/*
   This is used by make_class.pl

   START_CLASS_DEF
   CLASS      = accessor
   SUPER      = grib_accessor_class_long
   IMPLEMENTS = unpack_long
   IMPLEMENTS = pack_long
   IMPLEMENTS = init
   MEMBERS = const char* values
   MEMBERS = const char* binaryScaleFactor
   MEMBERS = const char* decimalScaleFactor
   MEMBERS = long bitsPerValue
   END_CLASS_DEF
 */

/* START_CLASS_IMP */

/*

Don't edit anything between START_CLASS_IMP and END_CLASS_IMP
Instead edit values between START_CLASS_DEF and END_CLASS_DEF
or edit "accessor.class" and rerun ./make_class.pl

*/

static int pack_long(grib_accessor*, const long* val,size_t *len);
static int unpack_long(grib_accessor*, long* val,size_t *len);
static void init(grib_accessor*,const long, grib_arguments* );
static void init_class(grib_accessor_class*);

typedef struct grib_accessor_second_order_bits_per_value {
    grib_accessor          att;
/* Members defined in gen */
/* Members defined in long */
/* Members defined in second_order_bits_per_value */
	const char* values;
	const char* binaryScaleFactor;
	const char* decimalScaleFactor;
	long bitsPerValue;
} grib_accessor_second_order_bits_per_value;

extern grib_accessor_class* grib_accessor_class_long;

static grib_accessor_class _grib_accessor_class_second_order_bits_per_value = {
    &grib_accessor_class_long,                      /* super                     */
    "second_order_bits_per_value",                      /* name                      */
    sizeof(grib_accessor_second_order_bits_per_value),  /* size                      */
    0,                           /* inited */
    &init_class,                 /* init_class */
    &init,                       /* init                      */
    0,                  /* post_init                      */
    0,                    /* free mem                       */
    0,                       /* describes himself         */
    0,                /* get length of section     */
    0,                /* get number of values      */
    0,                 /* get number of bytes      */
    0,                /* get offset to bytes           */
    0,            /* get native type               */
    0,                /* get sub_section                */
    0,               /* grib_pack procedures long      */
    0,               /* grib_pack procedures long      */
    &pack_long,                  /* grib_pack procedures long      */
    &unpack_long,                /* grib_unpack procedures long    */
    0,                /* grib_pack procedures double    */
    0,              /* grib_unpack procedures double  */
    0,                /* grib_pack procedures string    */
    0,              /* grib_unpack procedures string  */
    0,                 /* grib_pack procedures bytes     */
    0,               /* grib_unpack procedures bytes   */
    0,            /* pack_expression */
    0,              /* notify_change   */
    0,                /* update_size   */
    0,            /* preferred_size   */
    0,                    /* resize   */
    0,      /* nearest_smaller_value */
    0,                       /* next accessor    */
    0,                    /* compare vs. another accessor   */
    0,     /* unpack only ith value          */
    0,     /* unpack a subarray         */
    0,             		/* clear          */
};


grib_accessor_class* grib_accessor_class_second_order_bits_per_value = &_grib_accessor_class_second_order_bits_per_value;


static void init_class(grib_accessor_class* c)
{
	c->dump	=	(*(c->super))->dump;
	c->next_offset	=	(*(c->super))->next_offset;
	c->value_count	=	(*(c->super))->value_count;
	c->byte_count	=	(*(c->super))->byte_count;
	c->byte_offset	=	(*(c->super))->byte_offset;
	c->get_native_type	=	(*(c->super))->get_native_type;
	c->sub_section	=	(*(c->super))->sub_section;
	c->pack_missing	=	(*(c->super))->pack_missing;
	c->is_missing	=	(*(c->super))->is_missing;
	c->pack_double	=	(*(c->super))->pack_double;
	c->unpack_double	=	(*(c->super))->unpack_double;
	c->pack_string	=	(*(c->super))->pack_string;
	c->unpack_string	=	(*(c->super))->unpack_string;
	c->pack_bytes	=	(*(c->super))->pack_bytes;
	c->unpack_bytes	=	(*(c->super))->unpack_bytes;
	c->pack_expression	=	(*(c->super))->pack_expression;
	c->notify_change	=	(*(c->super))->notify_change;
	c->update_size	=	(*(c->super))->update_size;
	c->preferred_size	=	(*(c->super))->preferred_size;
	c->resize	=	(*(c->super))->resize;
	c->nearest_smaller_value	=	(*(c->super))->nearest_smaller_value;
	c->next	=	(*(c->super))->next;
	c->compare	=	(*(c->super))->compare;
	c->unpack_double_element	=	(*(c->super))->unpack_double_element;
	c->unpack_double_subarray	=	(*(c->super))->unpack_double_subarray;
	c->clear	=	(*(c->super))->clear;
}

/* END_CLASS_IMP */

static unsigned long nbits[32]={
                0x1, 0x2, 0x4, 0x8, 0x10, 0x20,
                0x40, 0x80, 0x100, 0x200, 0x400, 0x800,
                0x1000, 0x2000, 0x4000, 0x8000, 0x10000, 0x20000,
                0x40000, 0x80000, 0x100000, 0x200000, 0x400000, 0x800000,
                0x1000000, 0x2000000, 0x4000000, 0x8000000, 0x10000000, 0x20000000,
                0x40000000, 0x80000000
};

GRIB_INLINE static long number_of_bits(unsigned long x) {
    unsigned long *n=nbits;
    long i=0;
    while (x>=*n) {n++;i++;}
    return i;
}

static void init(grib_accessor* a,const long l, grib_arguments* c)
{
  int n=0;
  grib_accessor_second_order_bits_per_value* self = (grib_accessor_second_order_bits_per_value*)a;
  self->values = grib_arguments_get_name(a->parent->h,c,n++);
  self->binaryScaleFactor = grib_arguments_get_name(a->parent->h,c,n++);
  self->decimalScaleFactor = grib_arguments_get_name(a->parent->h,c,n++);
  self->bitsPerValue=0;
  
  a->length=0;
}

static int pack_long(grib_accessor* a, const long* val,size_t *len)
{
	grib_accessor_second_order_bits_per_value* self = (grib_accessor_second_order_bits_per_value*)a;
  	self->bitsPerValue=(long)*val;
	*len=1;

	return 0;
}

static int  unpack_long(grib_accessor* a, long* val, size_t *len)
{
  int ret=GRIB_SUCCESS;
  size_t size=0;
  size_t i;
  double max,min,d,b;
  double *values=0;
  long binaryScaleFactor,decimalScaleFactor;

  grib_accessor_second_order_bits_per_value* self = (grib_accessor_second_order_bits_per_value*)a;
  if (self->bitsPerValue) {
	*val=self->bitsPerValue;
  	return GRIB_SUCCESS;
  }

  if((ret = grib_get_size(a->parent->h, self->values,&size)) != GRIB_SUCCESS) {
	*val=self->bitsPerValue;
    return GRIB_SUCCESS;
  }

  if((ret = grib_get_long(a->parent->h, self->binaryScaleFactor,&binaryScaleFactor)) != GRIB_SUCCESS)
    return ret;

  if((ret = grib_get_long_internal(a->parent->h, self->decimalScaleFactor,&decimalScaleFactor)) != GRIB_SUCCESS)
    return ret;

  values=grib_context_malloc_clear(a->parent->h->context,sizeof(double)*size);
  if (!values) {
  	grib_context_log(a->parent->h->context,GRIB_LOG_FATAL,"%s unable to allocate %ld bytes",
		a->name,(long)size);
	return GRIB_OUT_OF_MEMORY;
  }
  if((ret = grib_get_double_array_internal(a->parent->h, self->values,values,&size)) != GRIB_SUCCESS)
    return ret;

  max=values[0];
  min=max;
  for (i=1;i<size;i++) {
  	if (max<values[i]) max=values[i];
	if (min>values[i]) min=values[i];
  }

  d=grib_power(-decimalScaleFactor,10);
  b=grib_power(-binaryScaleFactor,2);

  /* self->bitsPerValue=(long)ceil(log((double)((max-min)*d+1))/log(2.0))-binaryScaleFactor; */
  self->bitsPerValue=number_of_bits((unsigned long)(fabs(max-min)*b*d));
  *val=self->bitsPerValue;

  grib_context_free(a->parent->h->context,values);

  return ret;
}

