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Sourcecode: postgresql-8.4 version File versions

btree_utils_var.c

/*
 * $PostgreSQL: pgsql/contrib/btree_gist/btree_utils_var.c,v 1.20 2008/06/19 00:46:02 alvherre Exp $ 
 */
#include "btree_gist.h"

#include <math.h>
#include <limits.h>
#include <float.h>

#include "btree_utils_var.h"
#include "utils/pg_locale.h"
#include "utils/builtins.h"
#include "utils/rel.h"

PG_FUNCTION_INFO_V1(gbt_var_decompress);
Datum       gbt_var_decompress(PG_FUNCTION_ARGS);


Datum
gbt_var_decompress(PG_FUNCTION_ARGS)
{
      GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
      GBT_VARKEY *key = (GBT_VARKEY *) DatumGetPointer(PG_DETOAST_DATUM(entry->key));

      if (key != (GBT_VARKEY *) DatumGetPointer(entry->key))
      {
            GISTENTRY  *retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));

            gistentryinit(*retval, PointerGetDatum(key),
                                entry->rel, entry->page,
                                entry->offset, FALSE);

            PG_RETURN_POINTER(retval);
      }

      PG_RETURN_POINTER(entry);
}

/* Returns a better readable representaion of variable key ( sets pointer ) */
GBT_VARKEY_R
gbt_var_key_readable(const GBT_VARKEY * k)
{

      GBT_VARKEY_R r;

      r.lower = (bytea *) &(((char *) k)[VARHDRSZ]);
      if (VARSIZE(k) > (VARHDRSZ + (VARSIZE(r.lower))))
            r.upper = (bytea *) &(((char *) k)[VARHDRSZ + INTALIGN(VARSIZE(r.lower))]);
      else
            r.upper = r.lower;
      return r;
}


GBT_VARKEY *
gbt_var_key_copy(const GBT_VARKEY_R * u, bool force_node)
{
      GBT_VARKEY *r = NULL;

      if (u->lower == u->upper && !force_node)
      {                                         /* leaf key mode */
            r = (GBT_VARKEY *) palloc(VARSIZE(u->lower) + VARHDRSZ);
            memcpy(VARDATA(r), u->lower, VARSIZE(u->lower));
            SET_VARSIZE(r, VARSIZE(u->lower) + VARHDRSZ);
      }
      else
      {                                         /* node key mode  */
            r = (GBT_VARKEY *) palloc(INTALIGN(VARSIZE(u->lower)) + VARSIZE(u->upper) + VARHDRSZ);
            memcpy(VARDATA(r), u->lower, VARSIZE(u->lower));
            memcpy(VARDATA(r) + INTALIGN(VARSIZE(u->lower)), u->upper, VARSIZE(u->upper));
            SET_VARSIZE(r, INTALIGN(VARSIZE(u->lower)) + VARSIZE(u->upper) + VARHDRSZ);
      }
      return r;
}


static GBT_VARKEY *
gbt_var_leaf2node(GBT_VARKEY * leaf, const gbtree_vinfo * tinfo)
{
      GBT_VARKEY *out = leaf;

      if (tinfo->f_l2n)
            out = (*tinfo->f_l2n) (leaf);

      return out;
}


/*
 * returns the common prefix length of a node key
*/
static int32
gbt_var_node_cp_len(const GBT_VARKEY * node, const gbtree_vinfo * tinfo)
{

      GBT_VARKEY_R r = gbt_var_key_readable(node);
      int32       i = 0;
      int32       l = 0;
      int32       t1len = VARSIZE(r.lower) - VARHDRSZ;
      int32       t2len = VARSIZE(r.upper) - VARHDRSZ;
      int32       ml = Min(t1len, t2len);

      char     *p1 = VARDATA(r.lower);
      char     *p2 = VARDATA(r.upper);

      if (ml == 0)
            return 0;

      while (i < ml)
      {
            if (tinfo->eml > 1 && l == 0)
            {

                  if ((l = pg_mblen(p1)) != pg_mblen(p2))
                  {
                        return i;
                  }
            }
            if (*p1 != *p2)
            {
                  if (tinfo->eml > 1)
                  {
                        return (i - l + 1);
                  }
                  else
                  {
                        return i;
                  }
            }

            p1++;
            p2++;
            l--;
            i++;
      }
      return (ml);                        /* lower == upper */
}


/*
 * returns true, if query matches prefix ( common prefix )
*/
static bool
gbt_bytea_pf_match(const bytea *pf, const bytea *query, const gbtree_vinfo * tinfo)
{

      bool        out = FALSE;
      int32       k = 0;
      int32       qlen = VARSIZE(query) - VARHDRSZ;
      int32       nlen = VARSIZE(pf) - VARHDRSZ;

      if (nlen <= qlen)
      {
            char     *q = VARDATA(query);
            char     *n = VARDATA(pf);

            if (tinfo->eml > 1)
            {
                  out = (varstr_cmp(q, nlen, n, nlen) == 0);
            }
            else
            {
                  out = TRUE;
                  for (k = 0; k < nlen; k++)
                  {
                        if (*n != *q)
                        {
                              out = FALSE;
                              break;
                        }
                        if (k < (nlen - 1))
                        {
                              q++;
                              n++;
                        }
                  }
            }
      }

      return out;
}


/*
 * returns true, if query matches node using common prefix
*/

static bool
gbt_var_node_pf_match(const GBT_VARKEY_R * node, const bytea *query, const gbtree_vinfo * tinfo)
{

      return (tinfo->trnc && (
                                          gbt_bytea_pf_match(node->lower, query, tinfo) ||
                                          gbt_bytea_pf_match(node->upper, query, tinfo)
                                          ));

}


/*
*  truncates / compresses the node key
*  cpf_length .. common prefix length
*/
static GBT_VARKEY *
gbt_var_node_truncate(const GBT_VARKEY * node, int32 cpf_length, const gbtree_vinfo * tinfo)
{
      GBT_VARKEY *out = NULL;
      GBT_VARKEY_R r = gbt_var_key_readable(node);
      int32       len1 = VARSIZE(r.lower) - VARHDRSZ;
      int32       len2 = VARSIZE(r.upper) - VARHDRSZ;
      int32       si;
      char     *out2;

      len1 = Min(len1, (cpf_length + 1));
      len2 = Min(len2, (cpf_length + 1));

      si = 2 * VARHDRSZ + INTALIGN(len1 + VARHDRSZ) + len2;
      out = (GBT_VARKEY *) palloc(si);
      SET_VARSIZE(out, si);

      memcpy(VARDATA(out), r.lower, len1 + VARHDRSZ);
      SET_VARSIZE(VARDATA(out), len1 + VARHDRSZ);

      out2 = VARDATA(out) + INTALIGN(len1 + VARHDRSZ);
      memcpy(out2, r.upper, len2 + VARHDRSZ);
      SET_VARSIZE(out2, len2 + VARHDRSZ);

      return out;
}



void
gbt_var_bin_union(Datum *u, GBT_VARKEY * e, const gbtree_vinfo * tinfo)
{

      GBT_VARKEY *nk = NULL;
      GBT_VARKEY *tmp = NULL;
      GBT_VARKEY_R nr;
      GBT_VARKEY_R eo = gbt_var_key_readable(e);

      if (eo.lower == eo.upper)     /* leaf */
      {
            tmp = gbt_var_leaf2node(e, tinfo);
            if (tmp != e)
                  eo = gbt_var_key_readable(tmp);
      }

      if (DatumGetPointer(*u))
      {

            GBT_VARKEY_R ro = gbt_var_key_readable((GBT_VARKEY *) DatumGetPointer(*u));

            if ((*tinfo->f_cmp) ((bytea *) ro.lower, (bytea *) eo.lower) > 0)
            {
                  nr.lower = eo.lower;
                  nr.upper = ro.upper;
                  nk = gbt_var_key_copy(&nr, TRUE);
            }

            if ((*tinfo->f_cmp) ((bytea *) ro.upper, (bytea *) eo.upper) < 0)
            {
                  nr.upper = eo.upper;
                  nr.lower = ro.lower;
                  nk = gbt_var_key_copy(&nr, TRUE);
            }

            if (nk)
                  *u = PointerGetDatum(nk);
      }
      else
      {
            nr.lower = eo.lower;
            nr.upper = eo.upper;
            *u = PointerGetDatum(gbt_var_key_copy(&nr, TRUE));
      }
}



GISTENTRY *
gbt_var_compress(GISTENTRY *entry, const gbtree_vinfo * tinfo)
{

      GISTENTRY  *retval;

      if (entry->leafkey)
      {
            GBT_VARKEY *r = NULL;
            bytea    *leaf = (bytea *) DatumGetPointer(PG_DETOAST_DATUM(entry->key));
            GBT_VARKEY_R u;

            u.lower = u.upper = leaf;
            r = gbt_var_key_copy(&u, FALSE);

            retval = palloc(sizeof(GISTENTRY));
            gistentryinit(*retval, PointerGetDatum(r),
                                entry->rel, entry->page,
                                entry->offset, TRUE);
      }
      else
            retval = entry;

      return (retval);
}



GBT_VARKEY *
gbt_var_union(const GistEntryVector *entryvec, int32 *size, const gbtree_vinfo * tinfo)
{

      int               i = 0,
                        numranges = entryvec->n;
      GBT_VARKEY *cur;
      Datum       out;
      GBT_VARKEY_R rk;

      *size = sizeof(GBT_VARKEY);

      cur = (GBT_VARKEY *) DatumGetPointer(entryvec->vector[0].key);
      rk = gbt_var_key_readable(cur);
      out = PointerGetDatum(gbt_var_key_copy(&rk, TRUE));

      for (i = 1; i < numranges; i++)
      {
            cur = (GBT_VARKEY *) DatumGetPointer(entryvec->vector[i].key);
            gbt_var_bin_union(&out, cur, tinfo);
      }


      /* Truncate (=compress) key */
      if (tinfo->trnc)
      {
            int32       plen;
            GBT_VARKEY *trc = NULL;

            plen = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(out), tinfo);
            trc = gbt_var_node_truncate((GBT_VARKEY *) DatumGetPointer(out), plen + 1, tinfo);

            out = PointerGetDatum(trc);
      }

      return ((GBT_VARKEY *) DatumGetPointer(out));
}


bool
gbt_var_same(bool *result, const Datum d1, const Datum d2, const gbtree_vinfo * tinfo)
{

      GBT_VARKEY *t1 = (GBT_VARKEY *) DatumGetPointer(d1);
      GBT_VARKEY *t2 = (GBT_VARKEY *) DatumGetPointer(d2);
      GBT_VARKEY_R r1,
                        r2;

      r1 = gbt_var_key_readable(t1);
      r2 = gbt_var_key_readable(t2);

      if (t1 && t2)
      {
            *result = (((*tinfo->f_cmp) ((bytea *) r1.lower, (bytea *) r2.lower) == 0
                              && (*tinfo->f_cmp) ((bytea *) r1.upper, (bytea *) r2.upper) == 0) ? TRUE : FALSE);
      }
      else
            *result = (t1 == NULL && t2 == NULL) ? TRUE : FALSE;

      PG_RETURN_POINTER(result);
}



float *
gbt_var_penalty(float *res, const GISTENTRY *o, const GISTENTRY *n, const gbtree_vinfo * tinfo)
{

      GBT_VARKEY *orge = (GBT_VARKEY *) DatumGetPointer(o->key);
      GBT_VARKEY *newe = (GBT_VARKEY *) DatumGetPointer(n->key);
      GBT_VARKEY_R ok,
                        nk;
      GBT_VARKEY *tmp = NULL;

      *res = 0.0;

      nk = gbt_var_key_readable(newe);
      if (nk.lower == nk.upper)     /* leaf */
      {
            tmp = gbt_var_leaf2node(newe, tinfo);
            if (tmp != newe)
                  nk = gbt_var_key_readable(tmp);
      }
      ok = gbt_var_key_readable(orge);

      if ((VARSIZE(ok.lower) - VARHDRSZ) == 0 && (VARSIZE(ok.upper) - VARHDRSZ) == 0)
            *res = 0.0;
      else if (!(
                     (
                        ((*tinfo->f_cmp) (nk.lower, ok.lower) >= 0 || gbt_bytea_pf_match(ok.lower, nk.lower, tinfo)) &&
                        ((*tinfo->f_cmp) (nk.upper, ok.upper) <= 0 || gbt_bytea_pf_match(ok.upper, nk.upper, tinfo))
                        )
                     ))
      {
            Datum       d = PointerGetDatum(0);
            double            dres = 0.0;
            int32       ol,
                              ul;

            gbt_var_bin_union(&d, orge, tinfo);
            ol = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(d), tinfo);
            gbt_var_bin_union(&d, newe, tinfo);
            ul = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(d), tinfo);

            if (ul < ol)
            {
                  dres = (ol - ul); /* lost of common prefix len */
            }
            else
            {
                  GBT_VARKEY_R uk = gbt_var_key_readable((GBT_VARKEY *) DatumGetPointer(d));

                  char        tmp[4];

                  tmp[0] = ((VARSIZE(ok.lower) - VARHDRSZ) == ul) ? (CHAR_MIN) : (VARDATA(ok.lower)[ul]);
                  tmp[1] = ((VARSIZE(uk.lower) - VARHDRSZ) == ul) ? (CHAR_MIN) : (VARDATA(uk.lower)[ul]);
                  tmp[2] = ((VARSIZE(ok.upper) - VARHDRSZ) == ul) ? (CHAR_MIN) : (VARDATA(ok.upper)[ul]);
                  tmp[3] = ((VARSIZE(uk.upper) - VARHDRSZ) == ul) ? (CHAR_MIN) : (VARDATA(uk.upper)[ul]);
                  dres = (tmp[0] - tmp[1]) +
                        (tmp[3] - tmp[2]);
                  dres /= 256.0;
            }

            *res += FLT_MIN;
            *res += (float) (dres / ((double) (ol + 1)));
            *res *= (FLT_MAX / (o->rel->rd_att->natts + 1));
      }

      return res;
}


static int
gbt_vsrt_cmp(const void *a, const void *b, void *arg)
{
      GBT_VARKEY_R ar = gbt_var_key_readable(((const Vsrt *) a)->t);
      GBT_VARKEY_R br = gbt_var_key_readable(((const Vsrt *) b)->t);
      const gbtree_vinfo *tinfo = (const gbtree_vinfo *) arg;

      return (*tinfo->f_cmp) (ar.lower, br.lower);
}

GIST_SPLITVEC *
gbt_var_picksplit(const GistEntryVector *entryvec, GIST_SPLITVEC *v, const gbtree_vinfo * tinfo)
{
      OffsetNumber i,
                        maxoff = entryvec->n - 1;
      Vsrt     *arr;
      int               svcntr = 0,
                        nbytes;
      char     *cur;
      GBT_VARKEY **sv = NULL;

      arr = (Vsrt *) palloc((maxoff + 1) * sizeof(Vsrt));
      nbytes = (maxoff + 2) * sizeof(OffsetNumber);
      v->spl_left = (OffsetNumber *) palloc(nbytes);
      v->spl_right = (OffsetNumber *) palloc(nbytes);
      v->spl_ldatum = PointerGetDatum(0);
      v->spl_rdatum = PointerGetDatum(0);
      v->spl_nleft = 0;
      v->spl_nright = 0;

      sv = palloc(sizeof(bytea *) * (maxoff + 1));

      /* Sort entries */

      for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
      {
            GBT_VARKEY_R ro;

            cur = (char *) DatumGetPointer(entryvec->vector[i].key);
            ro = gbt_var_key_readable((GBT_VARKEY *) cur);
            if (ro.lower == ro.upper)           /* leaf */
            {
                  sv[svcntr] = gbt_var_leaf2node((GBT_VARKEY *) cur, tinfo);
                  arr[i].t = sv[svcntr];
                  if (sv[svcntr] != (GBT_VARKEY *) cur)
                        svcntr++;
            }
            else
                  arr[i].t = (GBT_VARKEY *) cur;
            arr[i].i = i;
      }

      /* sort */
      qsort_arg((void *) &arr[FirstOffsetNumber],
                    maxoff - FirstOffsetNumber + 1,
                    sizeof(Vsrt),
                    gbt_vsrt_cmp,
                    (void *) tinfo);

      /* We do simply create two parts */

      for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
      {
            if (i <= (maxoff - FirstOffsetNumber + 1) / 2)
            {
                  gbt_var_bin_union(&v->spl_ldatum, arr[i].t, tinfo);
                  v->spl_left[v->spl_nleft] = arr[i].i;
                  v->spl_nleft++;
            }
            else
            {
                  gbt_var_bin_union(&v->spl_rdatum, arr[i].t, tinfo);
                  v->spl_right[v->spl_nright] = arr[i].i;
                  v->spl_nright++;
            }
      }

      /* Truncate (=compress) key */
      if (tinfo->trnc)
      {
            int32       ll = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(v->spl_ldatum), tinfo);
            int32       lr = gbt_var_node_cp_len((GBT_VARKEY *) DatumGetPointer(v->spl_rdatum), tinfo);
            GBT_VARKEY *dl;
            GBT_VARKEY *dr;

            ll = Max(ll, lr);
            ll++;

            dl = gbt_var_node_truncate((GBT_VARKEY *) DatumGetPointer(v->spl_ldatum), ll, tinfo);
            dr = gbt_var_node_truncate((GBT_VARKEY *) DatumGetPointer(v->spl_rdatum), ll, tinfo);
            v->spl_ldatum = PointerGetDatum(dl);
            v->spl_rdatum = PointerGetDatum(dr);
      }

      return v;
}


/*
 * The GiST consistent method
 */
bool
gbt_var_consistent(
                           GBT_VARKEY_R * key,
                           const void *query,
                           const StrategyNumber *strategy,
                           bool is_leaf,
                           const gbtree_vinfo * tinfo
)
{
      bool        retval = FALSE;

      switch (*strategy)
      {
            case BTLessEqualStrategyNumber:
                  if (is_leaf)
                        retval = (*tinfo->f_ge) (query, (void *) key->lower);
                  else
                        retval = (*tinfo->f_cmp) ((bytea *) query, key->lower) >= 0
                              || gbt_var_node_pf_match(key, query, tinfo);
                  break;
            case BTLessStrategyNumber:
                  if (is_leaf)
                        retval = (*tinfo->f_gt) (query, (void *) key->lower);
                  else
                        retval = (*tinfo->f_cmp) ((bytea *) query, key->lower) >= 0
                              || gbt_var_node_pf_match(key, query, tinfo);
                  break;
            case BTEqualStrategyNumber:
                  if (is_leaf)
                        retval = (*tinfo->f_eq) (query, (void *) key->lower);
                  else
                        retval = (
                                      (
                                    (*tinfo->f_cmp) (key->lower, (bytea *) query) <= 0 &&
                          (*tinfo->f_cmp) ((bytea *) query, (void *) key->upper) <= 0
                                       ) || gbt_var_node_pf_match(key, query, tinfo)
                              );
                  break;
            case BTGreaterStrategyNumber:
                  if (is_leaf)
                        retval = (*tinfo->f_lt) (query, (void *) key->upper);
                  else
                        retval = (*tinfo->f_cmp) ((bytea *) query, key->upper) <= 0
                              || gbt_var_node_pf_match(key, query, tinfo);
                  break;
            case BTGreaterEqualStrategyNumber:
                  if (is_leaf)
                        retval = (*tinfo->f_le) (query, (void *) key->upper);
                  else
                        retval = (*tinfo->f_cmp) ((bytea *) query, key->upper) <= 0
                              || gbt_var_node_pf_match(key, query, tinfo);
                  break;
            default:
                  retval = FALSE;
      }

      return (retval);
}

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