static char rcsver[] = "$Id: buffs.c,v 1.11 2001/12/05 22:32:40 saadat Exp $";
 
/**
 ** $Source: /tes/cvs/vanilla/buffs.c,v $
 **
 ** $Log: buffs.c,v $
 ** Revision 1.11  2001/12/05 22:32:40  saadat
 ** If a "-select" field is specified multiple times. The multiple
 ** instances are assumed to be ORing to each other's selection.  Thus
 ** "-select 'detector 1 3 detector 6 6'" will select detectors 1-3 and 6.
 **
 ** Added code for indexing fixed-length array fields.
 **
 ** Revision 1.10  2000/09/01 17:27:30  saadat
 ** Added type-4 indices. Index update fixes.
 ** Added bit-fields based index searching during query processing.
 **
 ** This version has both qsort()-based and bits-based index searching,
 ** switchable thru Makefile.
 **
 ** Revision 1.9  2000/08/04 00:52:14  saadat
 ** Added a preliminary version of logging/statistics gathering on normal
 ** termination through exit() and on receipt of the following signals:
 **              SIGSEGV, SIGBUS, SIGPIPE, SIGXCPU, SIGXFSZ
 **
 ** Revision 1.8  2000/07/26 00:26:46  saadat
 ** Added preliminary code to create/use indices for searching.
 **
 ** Fragment record access mechanism has also been changed
 ** from a simple pointer to a record-handle structure.
 **
 ** Revision 1.7  2000/07/07 17:15:22  saadat
 ** Added support for Windows MS Visual C++ memory-mapped file support.
 ** Removed some unused variables from various files.
 **
 ** Revision 1.6  2000/02/11 00:35:49  saadat
 ** Missed something in the last change. Fixed.
 **
 ** Revision 1.5  2000/02/10 22:14:40  saadat
 ** Bug fix in V3.3.6 was not working properly, fixed.
 **
 ** for(i=initial; (i<final) && cond1; i++){
 ** 	if (cond2){
 ** 		set cond1;
 ** 	}
 ** }
 ** < -- i here is 1+i at the point where cond1 was set
 ** 	  (and that was the problem)
 **
 ** Revision 1.4  2000/02/09 22:26:02  saadat
 ** Bug in find_jump() while searching for the appropriate
 ** fragment in a table (given a key). It was not checking
 ** the limit on the number of fragments available, thus
 ** leading to a core dump.
 **
 ** Revision 1.3  2000/01/06 20:58:57  saadat
 ** -select on array[i] selected on array[0] instead of array[i]. Fixed.
 **
 ** Revision 1.2  1999/12/20 19:04:43  saadat
 ** Fix for buffer management:
 ** While searching for the required sclk_time in a table, the buffer management
 ** routines skipped over the table-fragments by looking at the start and end
 ** key values. When the required fragment is found, the "end" pointer value
 ** was not being set properly, thus resulting in skip over certain set of
 ** records.
 **
 **
 **/


#include <malloc.h>
#include <sys/types.h>
#include <string.h>
#include <assert.h>
#include "header.h"
#include "mem.h"

/* Creates a new TBLBUFF object for a given table object. User
 * supplies the record count for the buffer and the overlap count.
 * IMPORTANT: The overlap count MUST be at least two times the size of
 * the largest possible keyblock.
 */

#define EOFRAG(rhnd) ((rhnd).frp >= (rhnd).tbuff->end)

TBLBUFF *
NewTblBuff(TABLE *t)
{
    RHND rhnd;
    TBLBUFF *b;

    b = calloc(sizeof(TBLBUFF), 1);
    if (b == NULL){ return NULL; }
    
    b->tbl = t;
    
    rhnd = RefillTblBuff(b);
    if (RPTR(rhnd) == NULL){
      free(b);
      return(NULL);
    }
    
    return(b);
}

void
SelectResetIdxPPFlag(
   SELECT **selects,
   int      ns
)
{
  int i;
  SELECT *s;

  for(i = 0; i < ns; i++){
    for(s = selects[i]; s != NULL; s = s->next){
        s->idxpp = 0;
    }
  }
}


RHND
RefillTblBuff(TBLBUFF *b)
{
    char *fname;
    RHND  rhnd;

    if (b->buf != NULL) {
        MemUnMapFile(b->buf, b->len);
        if (b->varbuf) {
            MemUnMapFile(b->varbuf, b->varlen);
            b->varbuf = NULL;
        }
#ifdef DEBUG
		/* Following debug info is misleading since b->fileidx may
			not always be sequential. It can take jumps of one or
			more. See find_jump() for details.  */
        fname = (char *)b->tbl->files->ptr[b->fileidx];
        fprintf(stderr, "Unmapping %s\n", fname);
#endif
        b->fileidx++;
    }

    if (b->fileidx >= b->tbl->files->number) {
      INITRHND(rhnd);
      /* rhnd.tbuff = NULL; */
      return rhnd;
    }

	if (b->frag) FreeFragment(b->frag);
    fname = (char *)b->tbl->files->ptr[b->fileidx];
    assert((b->frag = AllocFragment()) != NULL);
    b->frag->fraghead = LoadFragHead(fname, b->tbl);
    b->len = b->frag->fraghead->sbuf.st_size;

#ifdef DEBUG
    fprintf(stderr, "mapping: %s\n", fname);
#endif

	b->buf = MemMapFile(NULL, b->len, PROT_READ, MAP_PRIVATE, fname, O_RDONLY, 0);
	if (b->buf == NULL){
		fprintf(stderr, "vanilla: Memory Mapping %s failed. ", fname?fname:"(null)");
		perror("Reason");
		abort();
	}

    /*
    ** Reset any SELECT->idxpp flags that may have been set during the
    ** last fragment's index processing.
    */

    /*
    ** Load Fragment Index - If one exists!
    ** Set new index preprocessing flags.
    */
	 if (b->tbl->selects != NULL) {
		SelectResetIdxPPFlag(
            (SELECT **)list_data(b->tbl->selects),
            list_count(b->tbl->selects));
        
		 b->frag->fragidx = LoadFragIdxAndMarkUsedSelects(
             fname, b->tbl->selects, b->tbl->label->name,
             b->frag->fraghead->nrows);

#ifdef DEBUG
         if (b->frag->fragidx != NULL){
             fprintf(stderr, "%s being processed through index.\n", fname);
         }
#endif /* DEBUG */
	 }
    /* Adjust current pointer */
    
    b->curr = b->buf + b->frag->fraghead->offset;
    b->end = b->buf + b->len;
    b->reclen = b->tbl->label->reclen;

    rhnd.tbuff = b;
    rhnd.frp = b->curr;
    rhnd.irec = 0;

    /*
    ** If index selection resulted in zero number of records, then
    ** the data in the table fragment has already exhausted. Set
    ** the next fragment record to the end of file.
    */
    if (b->frag->fragidx != NULL){
	 	if (b->frag->fragidx->n == 0){
			SETEOFRAG(rhnd);
		}
		else {
			RPTR(rhnd) += b->reclen * b->frag->fragidx->idxsel[0];
		}
		rhnd.irec = 1;
    }

    return rhnd;
}

PTR
GiveMeVarPtr(PTR raw, TABLE *table, int offset)
{
    TBLBUFF *b = table->buff;
    struct stat sbuf;
    char *fname, buf[256], *p;

    fname = ((char **)(table->files->ptr))[b->fileidx];
    if (b->varbuf == NULL) {
        strcpy(buf, fname);
        p = &buf[strlen(buf)-4];
        strcpy(p, ".var");
        if (stat(buf, &sbuf) != 0) {
            p = &buf[strlen(buf)-4];
            strcpy(p, ".VAR");		/* try capital case */
            if (stat(buf, &sbuf) != 0) {
				fprintf(stderr, "Unable to open var file: %s\n", buf);
				return(NULL);
            }
        }

    	/* fd = open(buf, O_RDONLY | O_BINARY); */
        b->varlen = sbuf.st_size;
        /* b->varbuf = mmap(NULL, b->varlen, PROT_READ, MAP_PRIVATE, fd, 0); */
		b->varbuf = MemMapFile(NULL, b->varlen, PROT_READ, MAP_PRIVATE, buf, O_RDONLY, 0);
		if (b->varbuf == NULL){
			fprintf(stderr, "vanilla: Memory Mapping %s failed. ", buf?buf:"(null)");
			perror("Reason");
			abort();
		}
    }

    if (offset >= b->varlen){
        fprintf(stderr, "vanilla: VarPtr beyond EOF. File %s. Aborting...",
                (fname? fname: "(null)"));
        abort();
    }

    return(b->varbuf+offset);
}

short
ConvertVaxVarByteCount(PTR raw, VARDATA *vdata)  
{
    char buf[4];
    short s;

    memcpy(buf, raw, 2);
    s = ((short *)MSB2(buf))[0];

    return(s);
}


/* Returns the first record in a table. This will ONLY WORK if it's the
 * first operation performed on the table. Calling this function after
 * we've done find's on the table will give useless results.
 */
RHND
GetFirstRec(TABLE * t)
{
  RHND rhnd;

  INITRHND(rhnd);
  rhnd.tbuff = t->buff;
  
  if (t->buff == NULL) {
    t->buff = NewTblBuff(t);
    
    rhnd.tbuff = t->buff;
    if (rhnd.tbuff != NULL){
      RPTR(rhnd) = t->buff->curr;

		if (t->buff->frag->fragidx != NULL){
			if (t->buff->frag->fragidx->n > 0){
				RPTR(rhnd) += t->buff->reclen * t->buff->frag->fragidx->idxsel[0];
			}
			else {
				RPTR(rhnd) = t->buff->end;
			}
			rhnd.irec = 1;
		}
    }
  }

  return rhnd;
}

RHND
GetNextRec(RHND rhnd)
{
  int frec;
  
  if (rhnd.tbuff != NULL){
    if (rhnd.tbuff->frag->fragidx == NULL){
      RPTR(rhnd) += rhnd.tbuff->reclen;
    }
    else {
      if (rhnd.irec < rhnd.tbuff->frag->fragidx->n){
        frec = rhnd.tbuff->frag->fragidx->idxsel[rhnd.irec];
        RPTR(rhnd) = rhnd.tbuff->curr + frec * rhnd.tbuff->reclen;
        rhnd.irec ++;
      }
      else {
        RPTR(rhnd) = rhnd.tbuff->end;
      }
    }
  }

  return rhnd;
}

RHND
GetEndOfFrag(TBLBUFF *b)
{
  RHND rhnd;

  INITRHND(rhnd);
  
  rhnd.tbuff = b;
  if (rhnd.tbuff != NULL){
    SETEOFRAG(rhnd);
  }

  return rhnd;
}

/**
 **/

RHND
find_jump(TABLE * t, FIELD * f, DATA d, RHND beg, RHND end, int deep)
{
    TBLBUFF *b = t->buff;
    int refill = 0;

    /* Added by Mankan, 5/99 */          
    FRAGMENT *frag;
    char *fname;

    int fileidx;
    DATA ek;
    /* */

    if (RPTR(beg) == NULL)  {
        beg = GetFirstRec(t);
    	b = t->buff;
    }

    if (RPTR(end) == NULL) {
        end = GetEndOfFrag(t->buff);
        refill = 1;
    }

    while (1) {
        /* Added by Mankan 5/99 */
        /*
        ** See if this record can even be in this fragment.
        ** This is terribly slow because it has to load the ODL
        ** header of each file.  A file index would speed this up a lot
        */
        if (deep==0) {
            frag = b->frag;
            ek = *((DATA **)(frag->fraghead->end_keys->ptr))[0];

			if (CompareData(ek,d,f) < 0 ) {
				for(fileidx = b->fileidx+1; fileidx < b->tbl->files->number; fileidx++){

					fname = (char *)b->tbl->files->ptr[fileidx];
					assert((frag = AllocFragment()) != NULL);
                    frag->fraghead = LoadFragHead(fname, b->tbl);

					/* The following line is quite restrictive */
					ek = *((DATA **)(frag->fraghead->end_keys->ptr))[0];

                    /* If a fragment containing the required key value (as
                       stored in variable "d") is found, load it and
                       continue with the processing */
                    if (CompareData(ek,d,f) >= 0){
								FreeFragment(frag);
								break;
						  }

					FreeFragment(frag);
				}

				if (fileidx < b->tbl->files->number){
                  /* A fragment potentially containing the required key is
                     found, so unmap the previous fragment and load this
                     instead. */
					#ifdef DEBUG
						fprintf(stderr, "Unmapping %s...\n",
								((char **)b->tbl->files->ptr)[b->fileidx]);
					#endif

					/* Save the fragment serial no (being referred to as fileidx here)
						that contains the required key value */
					/* Note: RefillTblBuff() increments b->fileidx before using it, that's
						why b->fileidx is one less than the actual fileidx */
					b->fileidx = fileidx - 1;

					/* Load data from the selected fragment */
					beg = RefillTblBuff(b);
					end = GetEndOfFrag(b);
				}
				else {
					/* List of fragments exhausted */
					#ifdef DEBUG
					fprintf(stderr, "find_jump[list-exhausted] %s...\n",
						((char **)b->tbl->files->ptr)[b->tbl->files->number-1]);
					#endif

                    RPTR(beg) = NULL;
					return beg;
				}
			}
        }

        /* */
        while (RPTR(beg) < RPTR(end) && CompareData(ConvertFieldData(RPTR(beg),f),d,f) < 0) {
          /* beg += b->reclen; */
            beg = GetNextRec(beg);

#ifdef DEBUG
            fprintf(stderr, "find_jump[1], ");
            fprintf(stderr, "%d / %d  %s\n", 
                    (RPTR(beg) - b->buf)/b->reclen,
                    (RPTR(end) - b->buf)/b->reclen,
                    b->tbl->files->ptr[b->fileidx]);
#endif
        }
        if (RPTR(beg) >= RPTR(end)) {
          if (refill) {
            beg = RefillTblBuff(b);
            if (RPTR(beg) == NULL){ return beg; }
            end = GetEndOfFrag(b);
#ifdef DEBUG
            printf("find_jump[2], refill %s\n", 
                   (char *)b->tbl->files->ptr[b->fileidx]);
#endif
            continue;
          } else {
            RPTR(beg) = NULL;
            return beg;
          }
        }
#ifdef DEBUG
        fprintf(stderr, "find_jump[3], match ");
        fprintf(stderr, "%d %s\n",(RPTR(beg) - b->buf)/b->reclen,
                b->tbl->files->ptr[b->fileidx]);
#endif
        return(beg);
    }
}    


RHND
find_until(TABLE * t, FIELD * f, RHND beg, RHND end)
{
    TBLBUFF *b  = t->buff;
    DATA d = ConvertFieldData(RPTR(beg), f);

    if (RPTR(end) == NULL){ end = GetEndOfFrag(b); }

    while ((beg = GetNextRec(beg), RPTR(beg) < RPTR(end)) && 
           EquivalentData(ConvertFieldData(RPTR(beg), f), d, f))  {
#ifdef DEBUG		   
        fprintf(stderr, "find_until: ");
        fprintf(stderr, "%d  %s\n",(RPTR(beg) - b->buf)/b->reclen, 
                b->tbl->files->ptr[b->fileidx]);
#endif
    }
    return(beg);
}



/**
 ** Returns non-zero if the data "d" maches the SELECTion
 ** criteria enforced on the field "s->field".
 **/
int
matchesSelectionCriteria(DATA d, SELECT *s)
{
    do {
        /**
         ** Selection criteria is matched if the following holds:
         **          d >= s->low
         **          d <= s->high
         **/

        /** The following was the actual condition that
         ** has been replaced.
         !(CompareData(d, s[i]->low, s[i]->field) < 0 ||
         CompareData(d, s[i]->high, s[i]->field) > 0)
        **/
        
        if (CompareData(d, s->low, s->field) >= 0 &&
            CompareData(d, s->high, s->field) <= 0){

            return 1;
        }
        s = s->next;
    }while(s);

    return 0;
}




RHND
find_select(TABLE * t, RHND beg, RHND end)
{
  DATA d;
  SELECT **s;
  int i, n, count = 0;
  TBLBUFF *b = t->buff;
  int refill = 0;
  RHND last;

  INITRHND(last);

  if (t->selects == NULL)  return(beg);
  s = (SELECT **)t->selects->ptr;
  n = t->selects->number;


  if (RPTR(end) == NULL) {
    RPTR(end) = b->end;
    refill = 1;
  }

  /**
   ** "i" contains a (mod n) index into the SELECTs. Where
   ** "n" is the size of the SELECT list attached to the
   ** current TABLE.
   ** On each SELECT match, the match count (i.e. the var
   ** "count") is incremented.
   ** If match fails at some point, the count is reset.
   ** Once the match count reaches "n" the selection is
   ** deemed successful.
   ** Resuming the search from the current index "i"
   ** means that at least the i'th SELECT is already
   ** matched.
   **/
  i = 0;
  
  while (1) {
    while (RPTR(beg) < RPTR(end)) {
      /*
      ** If the records for the current select i.e., s[i] have
      ** already been pruned during index processing, then, bypass
      ** this select. Otherwise, process it.
      */
      if (!s[i]->idxpp){
        d = ConvertData(RPTR(beg) + s[i]->start, s[i]->field);

        /*
        if (CompareData(d, s[i]->low, s[i]->field) < 0 ||
            CompareData(d, s[i]->high, s[i]->field) > 0)  {
        */
        if (!matchesSelectionCriteria(d, s[i])){
          beg = GetNextRec(beg);
          /* beg += b->reclen; */

          /*
          ** Selection mismatch, continue the-"while" until a
          ** match is found.
          */
          continue;
        }
      }
      
      /*
      ** Current selection matched.
      ** If the selection s[(i-1)%n] did not match on the same
      ** record, reset the number of selects ("count") matched.
      */
      if (RPTR(beg) != RPTR(last)) {
        last = beg; 
        count = 0;
      }
      i = (i+1)%n;
      if (++count == n) {
#ifdef DEBUG
        fprintf(stderr, "find_select[2]: match, ");
        fprintf(stderr, "%d  %s\n",(RPTR(beg) - b->buf)/b->reclen,
                b->tbl->files->ptr[b->fileidx]);
#endif
        return(beg);
      }
    }
    if (refill) {
      beg = RefillTblBuff(b);
      if (RPTR(beg) == NULL) return beg;
      end = GetEndOfFrag(b);
#ifdef DEBUG
      fprintf(stderr, "find_select[3]: refill  %s\n",
              b->tbl->files->ptr[b->fileidx]);
#endif
    } else {
      RPTR(beg) = NULL;
      return beg;
    }
  }

  /* unreachable */
}

/**
 ** Get the maximum value of the next record across all tables.
 ** This function also moves us across a fragment boundary (and sets up the
 ** first fragment) when necessary.
 **/
DATA *
maxFieldVal(SLICE * s, int dim, TABLE **tbl, DATA *maxValue)
{
  int i, rv = 0;
  DATA value;
  RHND beg;
  
  for (i = 0; i < dim; i++) {
    if (s[i].party_key == NULL)
      continue;
    
    if (RPTR(s[i].start_rec) == NULL) {		 /* No buffer loaded yet */
      s[i].start_rec = GetFirstRec(tbl[i]);
    } else if (RPTR(s[i].start_rec) == tbl[i]->buff->buf + tbl[i]->buff->len) {
      /* EOF of current bufer */
      beg = RefillTblBuff(tbl[i]->buff);
      if (RPTR(beg) == NULL) return NULL;
      s[i].start_rec = beg;
    }
    
    value = ConvertFieldData(RPTR(s[i].start_rec), s[i].party_key);
    
    if (!rv) {
      *maxValue = value;
      rv++;
    } else if (CompareData(value, *maxValue, s[i].party_key) > 0)
      *maxValue = value;
  }
  return maxValue;
}

/*
PTR
find_select(TABLE * t, PTR beg, PTR end)

find_select checks all the selects in a table, 
and returns the next record that satisfies.

If we had an index for the file, we could join the relevant blocks for each
field used, and have a list of rows ready to go.

*/