/*
 * contrib/btree_gist/btree_bit.c
 */
#include "postgres.h"

#include "btree_gist.h"
#include "btree_utils_var.h"
#include "utils/fmgrprotos.h"
#include "utils/sortsupport.h"
#include "utils/varbit.h"

/* GiST support functions */
PG_FUNCTION_INFO_V1(gbt_bit_compress);
PG_FUNCTION_INFO_V1(gbt_bit_union);
PG_FUNCTION_INFO_V1(gbt_bit_picksplit);
PG_FUNCTION_INFO_V1(gbt_bit_consistent);
PG_FUNCTION_INFO_V1(gbt_bit_penalty);
PG_FUNCTION_INFO_V1(gbt_bit_same);
PG_FUNCTION_INFO_V1(gbt_bit_sortsupport);
PG_FUNCTION_INFO_V1(gbt_varbit_sortsupport);


/* define for comparison */

static bool
gbt_bitgt(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(bitgt,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static bool
gbt_bitge(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(bitge,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static bool
gbt_biteq(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(biteq,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static bool
gbt_bitle(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(bitle,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static bool
gbt_bitlt(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetBool(DirectFunctionCall2(bitlt,
           PointerGetDatum(a),
           PointerGetDatum(b)));
}

static int32
gbt_bitcmp(const void *a, const void *b, Oid collation, FmgrInfo *flinfo)
{
 return DatumGetInt32(DirectFunctionCall2(byteacmp,
            PointerGetDatum(a),
            PointerGetDatum(b)));
}


static bytea *
gbt_bit_xfrm(bytea *leaf)
{
 bytea    *out = leaf;
 int   sz = VARBITBYTES(leaf) + VARHDRSZ;
 int   padded_sz = INTALIGN(sz);

 out = (bytea *) palloc(padded_sz);
 /* initialize the padding bytes to zero */
 while (sz < padded_sz)
  ((char *) out)[sz++] = 0;
 SET_VARSIZE(out, padded_sz);
 memcpy(VARDATA(out), VARBITS(leaf), VARBITBYTES(leaf));
 return out;
}




static GBT_VARKEY *
gbt_bit_l2n(GBT_VARKEY *leaf, FmgrInfo *flinfo)
{
 GBT_VARKEY *out = leaf;
 GBT_VARKEY_R r = gbt_var_key_readable(leaf);
 bytea    *o;

 o = gbt_bit_xfrm(r.lower);
 r.upper = r.lower = o;
 out = gbt_var_key_copy(&r);
 pfree(o);

 return out;
}

static const gbtree_vinfo tinfo =
{
 gbt_t_bit,
 0,
 true,
 gbt_bitgt,
 gbt_bitge,
 gbt_biteq,
 gbt_bitle,
 gbt_bitlt,
 gbt_bitcmp,
 gbt_bit_l2n
};


/**************************************************
 * GiST support functions
 **************************************************/

Datum
gbt_bit_compress(PG_FUNCTION_ARGS)
{
 GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);

 PG_RETURN_POINTER(gbt_var_compress(entry, &tinfo));
}

Datum
gbt_bit_consistent(PG_FUNCTION_ARGS)
{
 GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
 void    *query = DatumGetByteaP(PG_GETARG_DATUM(1));
 StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);

 /* Oid subtype = PG_GETARG_OID(3); */
 bool    *recheck = (bool *) PG_GETARG_POINTER(4);
 bool  retval;
 GBT_VARKEY *key = (GBT_VARKEY *) DatumGetPointer(entry->key);
 GBT_VARKEY_R r = gbt_var_key_readable(key);

 /* All cases served by this function are exact */
 *recheck = false;

 if (GIST_LEAF(entry))
  retval = gbt_var_consistent(&r, query, strategy, PG_GET_COLLATION(),
         true, &tinfo, fcinfo->flinfo);
 else
 {
  bytea    *q = gbt_bit_xfrm((bytea *) query);

  retval = gbt_var_consistent(&r, q, strategy, PG_GET_COLLATION(),
         false, &tinfo, fcinfo->flinfo);
 }
 PG_RETURN_BOOL(retval);
}

Datum
gbt_bit_union(PG_FUNCTION_ARGS)
{
 GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
 int32    *size = (int *) PG_GETARG_POINTER(1);

 PG_RETURN_POINTER(gbt_var_union(entryvec, size, PG_GET_COLLATION(),
         &tinfo, fcinfo->flinfo));
}

Datum
gbt_bit_picksplit(PG_FUNCTION_ARGS)
{
 GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
 GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);

 gbt_var_picksplit(entryvec, v, PG_GET_COLLATION(),
       &tinfo, fcinfo->flinfo);
 PG_RETURN_POINTER(v);
}

Datum
gbt_bit_same(PG_FUNCTION_ARGS)
{
 Datum  d1 = PG_GETARG_DATUM(0);
 Datum  d2 = PG_GETARG_DATUM(1);
 bool    *result = (bool *) PG_GETARG_POINTER(2);

 *result = gbt_var_same(d1, d2, PG_GET_COLLATION(), &tinfo, fcinfo->flinfo);
 PG_RETURN_POINTER(result);
}

Datum
gbt_bit_penalty(PG_FUNCTION_ARGS)
{
 GISTENTRY  *o = (GISTENTRY *) PG_GETARG_POINTER(0);
 GISTENTRY  *n = (GISTENTRY *) PG_GETARG_POINTER(1);
 float    *result = (float *) PG_GETARG_POINTER(2);

 PG_RETURN_POINTER(gbt_var_penalty(result, o, n, PG_GET_COLLATION(),
           &tinfo, fcinfo->flinfo));
}

static int
gbt_bit_ssup_cmp(Datum x, Datum y, SortSupport ssup)
{
 GBT_VARKEY *key1 = PG_DETOAST_DATUM(x);
 GBT_VARKEY *key2 = PG_DETOAST_DATUM(y);

 GBT_VARKEY_R arg1 = gbt_var_key_readable(key1);
 GBT_VARKEY_R arg2 = gbt_var_key_readable(key2);
 Datum  result;

 /* for leaf items we expect lower == upper, so only compare lower */
 result = DirectFunctionCall2(byteacmp,
         PointerGetDatum(arg1.lower),
         PointerGetDatum(arg2.lower));

 GBT_FREE_IF_COPY(key1, x);
 GBT_FREE_IF_COPY(key2, y);

 return DatumGetInt32(result);
}

Datum
gbt_bit_sortsupport(PG_FUNCTION_ARGS)
{
 SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);

 ssup->comparator = gbt_bit_ssup_cmp;
 ssup->ssup_extra = NULL;

 PG_RETURN_VOID();
}

Datum
gbt_varbit_sortsupport(PG_FUNCTION_ARGS)
{
 SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);

 ssup->comparator = gbt_bit_ssup_cmp;
 ssup->ssup_extra = NULL;

 PG_RETURN_VOID();
}