/*********************************************************************
 *   Copyright 2018, UCAR/Unidata
 *   See netcdf/COPYRIGHT file for copying and redistribution conditions.
 *********************************************************************/

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include "dapincludes.h"
#include "dceparselex.h"

#define DEBUG

#define LBRACE "{"
#define RBRACE "}"

static const char* opstrings[] = OPSTRINGS ;

static void ceallnodesr(DCEnode* node, NClist* allnodes, CEsort which);
static void dcedump(DCEnode* node, NCbytes* buf);
static void dcedumpraw(DCEnode* node, NCbytes* buf);
static void dcedumprawlist(NClist* list, NCbytes* buf);

#if 0 /*not currently used */
/* Parse incoming url constraints, if any,
   to check for syntactic correctness
*/ 
int
dapparseconstraints(char* constraints, DCEconstraint* dapconstraint)
{
    int ncstat = NC_NOERR;
    char* errmsg;

    assert(dapconstraint != NULL);
    nclistclear(dapconstraint->projections);
    nclistclear(dapconstraint->selections);

    ncstat = dapceparse(constraints,dapconstraint,&errmsg);
    if(ncstat) {
	nclog(NCLOGWARN,"DAP constraint parse failure: %s",errmsg);
	if(errmsg) free(errmsg);
        nclistclear(dapconstraint->projections);
        nclistclear(dapconstraint->selections);
    }

#ifdef DEBUG
fprintf(stderr,"constraint: %s",dcetostring((DCEnode*)dapconstraint));
#endif
    return ncstat;
}
#endif

#ifdef DEBUG1
static void
slicedump(const char* prefix, DCEslice* s)
{
#ifdef DCEVERBOSE
    fprintf(stderr,"%s: %s\n",prefix,dcetostring((DCEnode*)s));
#else
    size_t last = (s->first+s->length)-1;
    fprintf(stderr,"%s: [%lu:%lu:%lu p=%lu l=%lu c=%lu]\n",
	prefix,s->first,s->stride,last,s->last,s->length,s->count);
#endif
}
#endif


/*
Compose slice s1 with slice s2 -> sr
Compose means that the s2 constraint is applied
to the output of the s1 constraint.

Logical derivation of s1 compose s2 = sr
We have three index sequences to deal with,
where the sequence is the range [0..last].

1. the original data indices [0..N]
2. the indices resulting from applying slice s1;
   this will be a subset of #1 with the sequence
   [s1.first .. s1.last] where s1.last = s1.first + s1.length - 1
3. the indices resulting from applying s2:[0..s2.last] wrt
   to output of s2
   [s2.first .. s2.last]
   We can convert #3 into index sequence wrt
   #1 as follows
   [s2.first .. s2.last] -> [map(s2.first)..map(s2.last)]
   where map(int index) = s1.first + (s1.stride * index)
   Note that map(i) is undefined if map(i) > s1.last


So, we can compute the result (sr) stride and first as follows

. sr.stride = s1.stride * s2.stride

. sr.first   = map(s2.first) =  s1.first * (s1.stride * s2.first)
  This throws an exception if sr.first > s1.last

. compute the s1.last wrt original data
   last1 = s1.first + (s1.length - 1)

. compute the s2.last wrt s2
   last2 = s2.first + (s2.length - 1)

. compute candidate last wrt original index sequence
   lastx = map(last2) = s1.first + (s1.stride * last2)

. It is possible that lastx is outside of the range (s1.first..s1.last)
  so we take the min of last2 and lastx to ensure no overrun wrt s1
   sr.last = min(last1,lastx)

. If we want to be pedantic, we need to reduce
  sr.last so that it is on an exact multiple of sr.stride
  starting at sr.first
    delta = ((sr.last + (sr.stride-1)) / sr.stride) * sr.stride
    sr.last = sr.first + delta

. compute result length using sr.last
   sr.len = (sr.last + 1) - sr.first

Example 1:
0000000000111111111
0123456789012345678
 xxxxxxxxx
 0 1 2 3 4                s1=(f=1 st=2 len=9)
 0 1 2 3 4                s2=(f=0 st=1 len=5)
 xxxxxxxxxy
 0 1 3 4 5		  sr=(f=1 st=2 len=9..10)

Example 2:
0000000000111111111122222222223
0123456789012345678901234567890
 xxxxxxxxxxxxxxxxxxxxxxxxx
 0  1  2  3  4  5  6  7  8  _  _  _  s1=(f=1 st=3 len=25)
          0     1     2     3     4  s2=(f=3 st=2 len=5)
          xxxxxxxxxxxxxyyyyy
          0     1     2              sr=(f=10 st=6 l=13..17)

Example 3:
0000000000111111
0123456789012345
 xxxxxxxxx
 0 1 2 3 4 _ _            s1=(f=1 st=2 len=9)
     0 1 2 3 4            s2=(f=2 st=1 len=4)
     xxxxxy               ----------------------------
			  sr=(f=5 st=2 len=5..6)
Example 4:
0000000000111111111
0123456789012345678
 xxxxxxxxx
 0 1 2 3 4 _ _ _ _       s1=(f=1 st=2 len=9)
     0   1   2   3       s2=(f=2 st=2 len=4)
     xxxxxxyy
                          sr=(f=5 st=4 len=6..8)

Example 5:
00000000001
01234567890
xxx
012                       s1=(f=0 st=1 l=3)
012                       s2=(f=0 st=1 l=3)
xxx		          ----------------------------
012                       sr=(f=0 st=1 l=3)

Example 6:
00000
01234
xx
01                        s1=(f=0 st=1 l=2)
0                         s2=(f=0 st=1 l=1)
x		          ----------------------------
                          sr=(f=0 st=1 l=1)

*/

#define MAP(s1,i) ((s1)->first + ((s1)->stride*(i)))
#define XMIN(x,y) ((x) < (y) ? (x) : (y))
#define XMAX(x,y) ((x) > (y) ? (x) : (y))

int
dceslicecompose(DCEslice* s1, DCEslice* s2, DCEslice* result)
{
    int err = NC_NOERR;
    size_t lastx = 0;
    DCEslice sr; /* For back compatibility so s1 and result can be same object */
#ifdef DEBUG1
slicedump("compose: s1",s1);
slicedump("compose: s2",s2);
#endif
    sr.node.sort = CES_SLICE;
    sr.stride    = s1->stride * s2->stride;
    sr.first     = MAP(s1,s2->first);
    if(sr.first > s1->last)
	return NC_EINVALCOORDS;
    lastx        = MAP(s1,s2->last);
    sr.last      = XMIN(s1->last,lastx);
    sr.length    = (sr.last + 1) - sr.first;
    sr.declsize = XMAX(s1->declsize,s2->declsize); /* use max declsize */
    /* fill in other fields */
    sr.count = (sr.length + (sr.stride - 1))/sr.stride;
    *result = sr;
#ifdef DEBUG1
slicedump("compose: result",result);
#endif
    return err;
}

/*
Given two projection lists, merge
src into dst taking
overlapping projections into acct.
Dst will be modified.
*/

int
dcemergeprojectionlists(NClist* dst, NClist* src)
{
    int i;
    NClist* cat = nclistnew();
    int ncstat = NC_NOERR;

#ifdef DEBUG
fprintf(stderr,"dapmergeprojection: dst = %s\n",dcetostring((DCEnode*)dst));
fprintf(stderr,"dapmergeprojection: src = %s\n",dcetostring((DCEnode*)src));
#endif

    /* get dst concat clone(src) */
    nclistsetalloc(cat,nclistlength(dst)+nclistlength(src));
    for(i=0;i<nclistlength(dst);i++) {
	DCEprojection* p = (DCEprojection*)nclistget(dst,i);
	nclistpush(cat,(void*)p);
    }    
    for(i=0;i<nclistlength(src);i++) {
	DCEprojection* p = (DCEprojection*)nclistget(src,i);
	nclistpush(cat,(void*)dceclone((DCEnode*)p));
    }    

    nclistclear(dst);

    /* Repeatedly pull elements from the concat,
       merge with all duplicates, and stick into
       the dst
    */
    while(nclistlength(cat) > 0) {
	DCEprojection* target = (DCEprojection*)nclistremove(cat,0);
	if(target == NULL) continue;
        if(target->discrim != CES_VAR) continue;
        for(i=0;i<nclistlength(cat);i++) {
	    DCEprojection* p2 = (DCEprojection*)nclistget(cat,i);
	    if(p2 == NULL) continue;
	    if(p2->discrim != CES_VAR) continue;
	    if(dcesamepath(target->var->segments,
			   p2->var->segments)!=0) continue;
	    /* This entry matches our current target; merge  */
	    ncstat = dcemergeprojections(target,p2);
	    /* null out this merged entry and release it */
	    nclistset(cat,i,(void*)NULL);	    
	    dcefree((DCEnode*)p2);	    
	}		    
	/* Capture the clone */
	nclistpush(dst,(void*)target);
    }	    
    nclistfree(cat);
    return ncstat;
}

/* Modify merged projection to include "addition" projection */
int
dcemergeprojections(DCEprojection* merged, DCEprojection* addition)
{
    int ncstat = NC_NOERR;
    int i,j;

    ASSERT((merged->discrim == CES_VAR && addition->discrim == CES_VAR));
    ASSERT((nclistlength(merged->var->segments) == nclistlength(addition->var->segments)));    
    for(i=0;i<nclistlength(merged->var->segments);i++) {
	DCEsegment* mergedseg = (DCEsegment*)nclistget(merged->var->segments,i);
	DCEsegment* addedseg = (DCEsegment*)nclistget(addition->var->segments,i);
	/* If one segment has larger rank, then copy the extra slices unchanged */
	for(j=0;j<addedseg->rank;j++) {
	    if(j < mergedseg->rank)
	        dceslicecompose(mergedseg->slices+j,addedseg->slices+j,mergedseg->slices+j);
	    else
		mergedseg->slices[j] = addedseg->slices[j];
	}
	if(addedseg->rank > mergedseg->rank)
	    mergedseg->rank = addedseg->rank;
    }
    return ncstat;
}

/* Convert a DCEprojection instance into a string
   that can be used with the url
*/

char*
dcebuildprojectionstring(NClist* projections)
{
    char* pstring;
    NCbytes* buf = ncbytesnew();
    dcelisttobuffer(projections,buf,",");
    pstring = ncbytesdup(buf);
    ncbytesfree(buf);
    return pstring;
}

char*
dcebuildselectionstring(NClist* selections)
{
    NCbytes* buf = ncbytesnew();
    char* sstring;
    dcelisttobuffer(selections,buf,",");
    sstring = ncbytesdup(buf);
    ncbytesfree(buf);
    return sstring;
}

char*
dcebuildconstraintstring(DCEconstraint* constraints)
{
    NCbytes* buf = ncbytesnew();
    char* result = NULL;
    dcetobuffer((DCEnode*)constraints,buf);
    result = ncbytesdup(buf);
    ncbytesfree(buf);
    return result;
}

DCEnode*
dceclone(DCEnode* node)
{
    DCEnode* result = NULL;

    result = (DCEnode*)dcecreate(node->sort);
    if(result == NULL) goto done;

    switch (node->sort) {

    case CES_SLICE: {
	DCEslice* clone = (DCEslice*)result;
	DCEslice* orig = (DCEslice*)node;
	*clone = *orig;
    } break;

    case CES_SEGMENT: {
	DCEsegment* clone = (DCEsegment*)result;
	DCEsegment* orig = (DCEsegment*)node;
	*clone = *orig;	
        clone->name = nulldup(orig->name);
	if(orig->rank > 0)
	    memcpy(clone->slices,orig->slices,orig->rank*sizeof(DCEslice));
    } break;

    case CES_VAR: {
	DCEvar* clone = (DCEvar*)result;
	DCEvar* orig = (DCEvar*)node;
	*clone = *orig;
	clone->segments = dceclonelist(clone->segments);
    } break;

    case CES_FCN: {
	DCEfcn* clone = (DCEfcn*)result;
	DCEfcn* orig = (DCEfcn*)node;
	*clone = *orig;
        clone->name = nulldup(orig->name);
	clone->args = dceclonelist(orig->args);
    } break;

    case CES_CONST: {
	DCEconstant* clone = (DCEconstant*)result;
	DCEconstant* orig = (DCEconstant*)node;
	*clone = *orig;
        if(clone->discrim ==  CES_STR)
	    clone->text = nulldup(clone->text);
    } break;

    case CES_VALUE: {
	DCEvalue* clone = (DCEvalue*)result;
	DCEvalue* orig = (DCEvalue*)node;
	*clone = *orig;
        switch (clone->discrim) {
        case CES_CONST:
	    clone->constant = (DCEconstant*)dceclone((DCEnode*)orig->constant); break;
        case CES_VAR:
	    clone->var = (DCEvar*)dceclone((DCEnode*)orig->var); break;
        case CES_FCN:
	    clone->fcn = (DCEfcn*)dceclone((DCEnode*)orig->fcn); break;
        default: assert(0);
        }
    } break;

    case CES_PROJECT: {
	DCEprojection* clone = (DCEprojection*)result;
	DCEprojection* orig = (DCEprojection*)node;
	*clone = *orig;	
	switch (orig->discrim) {
	case CES_VAR:
            clone->var = (DCEvar*)dceclone((DCEnode*)orig->var); break;
	case CES_FCN:
            clone->fcn = (DCEfcn*)dceclone((DCEnode*)orig->fcn); break;
	default: assert(0);
	}
    } break;

    case CES_SELECT: {
	DCEselection* clone = (DCEselection*)result;
	DCEselection* orig = (DCEselection*)node;
	*clone = *orig;	
	clone->lhs = (DCEvalue*)dceclone((DCEnode*)orig->lhs);
	clone->rhs = dceclonelist(orig->rhs);
    } break;

    case CES_CONSTRAINT: {
	DCEconstraint* clone = (DCEconstraint*)result;
	DCEconstraint* orig = (DCEconstraint*)node;
	*clone = *orig;	
	clone->projections = dceclonelist(orig->projections);	
	clone->selections = dceclonelist(orig->selections);
    } break;

    default:
	assert(0);
    }

done:
    return result;
}

NClist*
dceclonelist(NClist* list)
{
    int i;
    NClist* clone;
    if(list == NULL) return NULL;
    clone = nclistnew();
    for(i=0;i<nclistlength(list);i++) {
	DCEnode* node = (DCEnode*)nclistget(list,i);
	DCEnode* newnode = dceclone((DCEnode*)node);
	nclistpush(clone,(void*)newnode);
    }
    return clone;
}

void
dcefree(DCEnode* node)
{
    if(node == NULL) return;

    switch (node->sort) {

    case CES_VAR: {
	DCEvar* target = (DCEvar*)node;
	dcefreelist(target->segments);	
    } break;

    case CES_FCN: {
	DCEfcn* target = (DCEfcn*)node;
	dcefreelist(target->args);	
        nullfree(target->name);
    } break;

    case CES_CONST: {
	DCEconstant* target = (DCEconstant*)node;
	if(target->discrim == CES_STR)
	    nullfree(target->text);
    } break;

    case CES_VALUE: {
	DCEvalue* target = (DCEvalue*)node;
	switch(target->discrim) {
        case CES_CONST: dcefree((DCEnode*)target->constant); break;    
        case CES_VAR: dcefree((DCEnode*)target->var); break;    
        case CES_FCN: dcefree((DCEnode*)target->fcn); break;    
        default: assert(0);
        }
    } break;

    case CES_PROJECT: {
	DCEprojection* target = (DCEprojection*)node;
	switch (target->discrim) {
	case CES_VAR: dcefree((DCEnode*)target->var); break;
	case CES_FCN: dcefree((DCEnode*)target->fcn); break;
	default: assert(0);
	}
    } break;

    case CES_SELECT: {
	DCEselection* target = (DCEselection*)node;
	dcefreelist(target->rhs);
	dcefree((DCEnode*)target->lhs);
    } break;

    case CES_CONSTRAINT: {
	DCEconstraint* target = (DCEconstraint*)node;
	dcefreelist(target->projections);
	dcefreelist(target->selections);
    } break;

    case CES_SEGMENT: {
	DCEsegment* target = (DCEsegment*)node;
	target->rank = 0;
        nullfree(target->name);
    } break;

    case CES_SLICE: {
    } break;

    default:
	assert(0);
    }

    /* final action */
    free(node);
}

void
dcefreelist(NClist* list)
{
    int i;
    if(list == NULL) return;
    for(i=0;i<nclistlength(list);i++) {
	DCEnode* node = (DCEnode*)nclistget(list,i);
	dcefree((DCEnode*)node);
    }
    nclistfree(list);
}

char*
dcetostring(DCEnode* node)
{
    char* s;
    NCbytes* buf = ncbytesnew();
    dcetobuffer(node,buf);
    s = ncbytesextract(buf);
    ncbytesfree(buf);
    return s;
}

/* Mostly for debugging */
char*
dcerawtostring(void* node)
{
    char* s;
    NCbytes* buf = ncbytesnew();
    dcedumpraw((DCEnode*)node,buf);
    s = ncbytesextract(buf);
    ncbytesfree(buf);
    return s;
}

char*
dcerawlisttostring(NClist* list)
{
    char* s;
    NCbytes* buf = ncbytesnew();
    dcedumprawlist(list,buf);
    s = ncbytesextract(buf);
    ncbytesfree(buf);
    return s;
}

void
dcetobuffer(DCEnode* node, NCbytes* buf)
{
    dcedump(node,buf);
}

static void
dcedump(DCEnode* node, NCbytes* buf)
{
    char tmp[1024];

    if(buf == NULL) return;
    if(node == NULL) {ncbytescat(buf,"<null>"); return;}

    switch (node->sort) {

    case CES_SLICE: {
	    DCEslice* slice = (DCEslice*)node;
	    size_t last = (slice->first+slice->length)-1;
            if(slice->count == 1) {
                snprintf(tmp,sizeof(tmp),"[%lu]",
	            (unsigned long)slice->first);
            } else if(slice->stride == 1) {
                snprintf(tmp,sizeof(tmp),"[%lu:%lu]",
	            (unsigned long)slice->first,
	            (unsigned long)last);
            } else {
	        snprintf(tmp,sizeof(tmp),"[%lu:%lu:%lu]",
		    (unsigned long)slice->first,
		    (unsigned long)slice->stride,
		    (unsigned long)last);
	    }
            ncbytescat(buf,tmp);
    } break;

    case CES_SEGMENT: {
	DCEsegment* segment = (DCEsegment*)node;
	char* name = (segment->name?segment->name:"<unknown>");
        int rank = segment->rank;
	int i;
	name = nulldup(name);
	ncbytescat(buf,name);
	nullfree(name);
        if(!dceiswholesegment(segment)) {
            for(i=0;i<rank;i++) {
	        DCEslice* slice = segment->slices+i;
                dcetobuffer((DCEnode*)slice,buf);
	    }
	}
    } break;

    case CES_VAR: {
	DCEvar* var = (DCEvar*)node;
	dcelisttobuffer(var->segments,buf,".");
    } break;

    case CES_FCN: {
	DCEfcn* fcn = (DCEfcn*)node;
        ncbytescat(buf,fcn->name);
        ncbytescat(buf,"(");
	dcelisttobuffer(fcn->args,buf,",");
        ncbytescat(buf,")");
    } break;

    case CES_CONST: {
	DCEconstant* value = (DCEconstant*)node;
        switch (value->discrim) {
        case CES_STR:
	    ncbytescat(buf,value->text);
	    break;		
        case CES_INT:
            snprintf(tmp,sizeof(tmp),"%lld",value->intvalue);
            ncbytescat(buf,tmp);
    	break;
        case CES_FLOAT:
            snprintf(tmp,sizeof(tmp),"%g",value->floatvalue);
            ncbytescat(buf,tmp);
	    break;
        default: assert(0);
	}
    } break;

    case CES_VALUE: {
	DCEvalue* value = (DCEvalue*)node;
        switch (value->discrim) {
        case CES_CONST:
    	    dcetobuffer((DCEnode*)value->constant,buf);
      	    break;		
        case CES_VAR:
    	    dcetobuffer((DCEnode*)value->var,buf);
    	    break;
        case CES_FCN:
    	    dcetobuffer((DCEnode*)value->fcn,buf);
    	    break;
        default: assert(0);
        }
    } break;

    case CES_PROJECT: {
	DCEprojection* target = (DCEprojection*)node;
	switch (target->discrim) {
	case CES_VAR:
	    dcetobuffer((DCEnode*)target->var,buf);
	    break;
	case CES_FCN: dcetobuffer((DCEnode*)target->fcn,buf); break;
	default: assert(0);
	}
    } break;

    case CES_SELECT: {
	DCEselection* sel = (DCEselection*)node;
	dcetobuffer((DCEnode*)sel->lhs,buf);
        if(sel->operator == CES_NIL) break;
        ncbytescat(buf,opstrings[(int)sel->operator]);
        if(nclistlength(sel->rhs) > 1)
            ncbytescat(buf,"{");
	dcelisttobuffer(sel->rhs,buf,",");
        if(nclistlength(sel->rhs) > 1)
	    ncbytescat(buf,"}");
    } break;

    case CES_CONSTRAINT: {
	DCEconstraint* con = (DCEconstraint*)node;
        if(con->projections != NULL && nclistlength(con->projections) > 0) {
            dcelisttobuffer(con->projections,buf,",");
	}
        if(con->selections != NULL && nclistlength(con->selections) > 0) {
	    ncbytescat(buf,"&"); /* because & is really a prefix */
            dcelisttobuffer(con->selections,buf,"&");
	}
    } break;

    case CES_NIL: {
	ncbytescat(buf,"<nil>");
    } break;

    default:
	assert(0);
    }
}

char*
dcelisttostring(NClist* list, char* sep)
{
    char* s;
    NCbytes* buf = ncbytesnew();
    dcelisttobuffer(list,buf,sep);
    s = ncbytesextract(buf);
    ncbytesfree(buf);
    return s;
}

void
dcelisttobuffer(NClist* list, NCbytes* buf, char* sep)
{
    int i;
    if(list == NULL || buf == NULL) return;
    if(sep == NULL) sep = ",";
    for(i=0;i<nclistlength(list);i++) {
	DCEnode* node = (DCEnode*)nclistget(list,i);
	if(node == NULL) continue;
	if(i>0) ncbytescat(buf,sep);
	dcetobuffer((DCEnode*)node,buf);
    }
}

/* Collect all nodes within a specified constraint tree */
/* Caller frees result */
NClist*
dceallnodes(DCEnode* node, CEsort which)
{
    NClist* allnodes = nclistnew();
    ceallnodesr(node,allnodes,which);
    return allnodes;
}

static void
ceallnodesr(DCEnode* node, NClist* allnodes, CEsort which)
{
    int i;
    if(node == NULL) return;
    if(nclistcontains(allnodes,(void*)node)) return;
    if(which == CES_NIL || node->sort == which)
        nclistpush(allnodes,(void*)node);
    switch(node->sort) {
    case CES_FCN: {
	DCEfcn* fcn = (DCEfcn*)node;
	for(i=0;i<nclistlength(fcn->args);i++) {
	    ceallnodesr((DCEnode*)nclistget(fcn->args,i),allnodes,which);
	}
    } break;
    case CES_VAR: {
	DCEvar* var = (DCEvar*)node;
	for(i=0;i<nclistlength(var->segments);i++) {
	    ceallnodesr((DCEnode*)nclistget(var->segments,i),allnodes,which);
	}
    } break;
    case CES_VALUE: {
	DCEvalue* value = (DCEvalue*)node;
	if(value->discrim == CES_VAR)
	    ceallnodesr((DCEnode*)value->var,allnodes,which);
	else if(value->discrim == CES_FCN)
	    ceallnodesr((DCEnode*)value->fcn,allnodes,which);
	else
	    ceallnodesr((DCEnode*)value->constant,allnodes,which);
    } break;
    case CES_SELECT: {
	DCEselection* selection = (DCEselection*)node;
        ceallnodesr((DCEnode*)selection->lhs,allnodes,which);
	for(i=0;i<nclistlength(selection->rhs);i++)
            ceallnodesr((DCEnode*)nclistget(selection->rhs,i),allnodes,which);
    } break;
    case CES_PROJECT: {
	DCEprojection* projection = (DCEprojection*)node;
	if(projection->discrim == CES_VAR)
	    ceallnodesr((DCEnode*)projection->var,allnodes,which);
	else
	    ceallnodesr((DCEnode*)projection->fcn,allnodes,which);
    } break;
    case CES_CONSTRAINT: {
	DCEconstraint* constraint = (DCEconstraint*)node;
	for(i=0;i<nclistlength(constraint->projections);i++)
	    ceallnodesr((DCEnode*)nclistget(constraint->projections,i),allnodes,which);
	for(i=0;i<nclistlength(constraint->selections);i++)
	    ceallnodesr((DCEnode*)nclistget(constraint->selections,i),allnodes,which);
    } break;

    /* All others have no subnodes */
    default:
	break;
    }
}

DCEnode*
dcecreate(CEsort sort)
{
    DCEnode* node = NULL;

    switch (sort) {

    case CES_SLICE: {
	DCEslice* target = (DCEslice*)calloc(1,sizeof(DCEslice));
	if(target == NULL) return NULL;
	node = (DCEnode*)target;
    } break;

    case CES_SEGMENT: {
	int i;
	DCEsegment* target = (DCEsegment*)calloc(1,sizeof(DCEsegment));
	if(target == NULL) return NULL;
	/* Initialize the sort of the slices */
	for(i=0;i<NC_MAX_VAR_DIMS;i++)
	    target->slices[i].node.sort = CES_SLICE;		
	node = (DCEnode*)target;
    } break;

    case CES_CONST: {
	DCEconstant* target = (DCEconstant*)calloc(1,sizeof(DCEconstant));
	if(target == NULL) return NULL;
	node = (DCEnode*)target;
	target->discrim = CES_NIL;
    } break;

    case CES_VALUE: {
	DCEvalue* target = (DCEvalue*)calloc(1,sizeof(DCEvalue));
	if(target == NULL) return NULL;
	node = (DCEnode*)target;
	target->discrim = CES_NIL;
    } break;

    case CES_VAR: {
	DCEvar* target = (DCEvar*)calloc(1,sizeof(DCEvar));
	if(target == NULL) return NULL;
	node = (DCEnode*)target;
    } break;

    case CES_FCN: {
	DCEfcn* target = (DCEfcn*)calloc(1,sizeof(DCEfcn));
	if(target == NULL) return NULL;
	node = (DCEnode*)target;
    } break;

    case CES_PROJECT: {
	DCEprojection* target = (DCEprojection*)calloc(1,sizeof(DCEprojection));
	if(target == NULL) return NULL;
	node = (DCEnode*)target;
    } break;

    case CES_SELECT: {
	DCEselection* target = (DCEselection*)calloc(1,sizeof(DCEselection));
	if(target == NULL) return NULL;
	node = (DCEnode*)target;
	target->operator = CEO_NIL;
    } break;

    case CES_CONSTRAINT: {
	DCEconstraint* target = (DCEconstraint*)calloc(1,sizeof(DCEconstraint));
	if(target == NULL) return NULL;
	node = (DCEnode*)target;
    } break;

    default:
	assert(0);
    }

    /* final action */
    node->sort = sort;
    return node;
}

int
dceiswholeslice(DCEslice* slice)
{
    if(slice->first != 0
       || slice->stride != 1
       || slice->length != slice->declsize) return 0;
    return 1;
}

int
dceiswholesegment(DCEsegment* seg)
{
    int i,whole;
    
    if(!seg->slicesdefined) return 0; /* actually, we don't know */
    whole = 1; /* assume so */
    for(i=0;i<seg->rank;i++) {
	if(!dceiswholeslice(&seg->slices[i])) {whole = 0; break;}	
    }
    return whole;
}

void
dcemakewholeslice(DCEslice* slice, size_t declsize)
{
    slice->first = 0;
    slice->stride = 1;
    slice->length = declsize;
    slice->declsize = declsize;
    slice->count = declsize;
    slice->last = slice->length - 1;
}

/* Remove slicing from terminal segment of p */
void
dcemakewholeprojection(DCEprojection* p)
{
    /* Remove the slicing (if any) from the last segment */
    if(p->discrim == CES_VAR && p->var != NULL && p->var->segments != NULL) {
        int lastindex = nclistlength(p->var->segments) - 1;
        DCEsegment* lastseg = (DCEsegment*)nclistget(p->var->segments,lastindex);
        lastseg->rank = 0;
    }   
}

int
dcesamepath(NClist* list1, NClist* list2)
{
    int i;
    int len = nclistlength(list1);
    if(len != nclistlength(list2)) return 0;
    for(i=0;i<len;i++) {
	DCEsegment* s1 = (DCEsegment*)nclistget(list1,i);
	DCEsegment* s2 = (DCEsegment*)nclistget(list2,i);
	if(strcmp(s1->name,s2->name) != 0) return 0;
    }
    return 1;
}

void
dcesegment_transpose(DCEsegment* segment,
				 size_t* start,
				 size_t* count,
				 size_t* stride,
				 size_t* sizes
				)
{
    int i;
    if(segment != NULL && sizes != NULL) {
        for(i=0;i<segment->rank;i++) {
	    if(start != NULL) start[i] = segment->slices[i].first;
	    if(count != NULL) count[i] = segment->slices[i].count;
	    if(stride != NULL) stride[i] = (size_t)segment->slices[i].stride;
	    if(sizes != NULL) sizes[i] = segment->slices[i].declsize;
	}
    }	
}

/* Compute segment size for subset of slices */
size_t
dcesegmentsize(DCEsegment* seg, size_t start, size_t stop)
{
    int i, count;
    if(!seg->slicesdefined) return 0; /* actually, we don't know */
    for(count=1,i=start;i<stop;i++) {
	count *= seg->slices[i].count;
    }
    return count;
}

/* Return the index of the leftmost slice
   starting at start and up to, but not including
   stop, such that it and all slices to the right
   are "safe". Safe means dceiswholeslice() is true.
   In effect, we can read the safe index set as a
   single chunk. Return stop if there is no safe index.
*/

size_t
dcesafeindex(DCEsegment* seg, size_t start, size_t stop)
{
    size_t safe;
    if(!seg->slicesdefined) return stop; /* actually, we don't know */
    if(stop == 0) return stop;
    /* watch out because safe is unsigned */
    for(safe=stop-1;safe>start;safe--) {
	if(!dceiswholeslice(&seg->slices[safe])) return safe+1;
    }
    return dceiswholeslice(&seg->slices[start]) ? start /*every slice is safe*/
                                                 : start+1 ;
}


static const char*
dcesortname(CEsort sort)
{
    switch (sort) {
    case CES_SLICE: return "SLICE";
    case CES_SEGMENT: return "SEGMENT";
    case CES_VAR: return "VAR";
    case CES_FCN: return "FCN";
    case CES_CONST: return "CONST";
    case CES_VALUE: return "VALUE";
    case CES_PROJECT: return "PROJECT";
    case CES_SELECT: return "SELECT";
    case CES_CONSTRAINT: return "CONSTRAINT";
    case CES_STR: return "STR";
    case CES_INT: return "INT";
    case CES_FLOAT: return "FLOAT";
    default: break;
    }
    return "UNKNOWN";
}

static void
dcedumpraw(DCEnode* node, NCbytes* buf)
{
    int i;
    char tmp[1024];

    if(buf == NULL) return;
    if(node == NULL) {ncbytescat(buf,"<null>"); return;}

    ncbytescat(buf,LBRACE);
    ncbytescat(buf,(char*)dcesortname(node->sort));

    switch (node->sort) {

    case CES_SLICE: {
	    DCEslice* slice = (DCEslice*)node;
	    snprintf(tmp,sizeof(tmp),
		    " [first=%lu stride=%lu last=%lu len=%lu count=%lu size=%lu]",
		    (unsigned long)slice->first,
		    (unsigned long)slice->stride,
		    (unsigned long)slice->last,
		    (unsigned long)slice->length,
		    (unsigned long)slice->count,
		    (unsigned long)slice->declsize);
            ncbytescat(buf,tmp);
    } break;

    case CES_SEGMENT: {
	DCEsegment* segment = (DCEsegment*)node;
        int rank = segment->rank;
	char* name = (segment->name?segment->name:"<unknown>");
	ncbytescat(buf," name=");
	ncbytescat(buf,name);
        snprintf(tmp,sizeof(tmp)," rank=%lu",(unsigned long)rank);
	ncbytescat(buf,tmp);
        ncbytescat(buf," defined=");
        ncbytescat(buf,(segment->slicesdefined?"1":"0"));
        ncbytescat(buf," declized=");
        ncbytescat(buf,(segment->slicesdeclized?"1":"0"));
	if(rank > 0) {
            ncbytescat(buf," slices=");
            for(i=0;i<rank;i++) {
	        DCEslice* slice = segment->slices+i;
                dcedumpraw((DCEnode*)slice,buf);
	    }
	}
    } break;

    case CES_VAR: {
	DCEvar* var = (DCEvar*)node;
        ncbytescat(buf," segments=");
	dcedumprawlist(var->segments,buf);
    } break;

    case CES_FCN: {
	DCEfcn* fcn = (DCEfcn*)node;
	ncbytescat(buf," name=");
        ncbytescat(buf,fcn->name);
        ncbytescat(buf,"args=");
	dcedumprawlist(fcn->args,buf);
    } break;

    case CES_CONST: {
	DCEconstant* value = (DCEconstant*)node;
	ncbytescat(buf," discrim=");
	ncbytescat(buf,dcesortname(value->discrim));
	ncbytescat(buf," value=");
        switch (value->discrim) {
        case CES_STR:
	    ncbytescat(buf,"|");
	    ncbytescat(buf,value->text);
	    ncbytescat(buf,"|");
	    break;		
        case CES_INT:
            snprintf(tmp,sizeof(tmp),"%lld",value->intvalue);
            ncbytescat(buf,tmp);
    	break;
        case CES_FLOAT:
            snprintf(tmp,sizeof(tmp),"%g",value->floatvalue);
            ncbytescat(buf,tmp);
	    break;
        default: assert(0);
	}
    } break;

    case CES_VALUE: {
	DCEvalue* value = (DCEvalue*)node;
	ncbytescat(buf," discrim=");
	ncbytescat(buf,dcesortname(value->discrim));
        switch (value->discrim) {
        case CES_CONST:
    	    dcedumpraw((DCEnode*)value->constant,buf);
      	    break;		
        case CES_VAR:
    	    dcedumpraw((DCEnode*)value->var,buf);
    	    break;
        case CES_FCN:
    	    dcedumpraw((DCEnode*)value->fcn,buf);
    	    break;
        default: assert(0);
        }
    } break;

    case CES_PROJECT: {
	DCEprojection* target = (DCEprojection*)node;
	ncbytescat(buf," discrim=");
	ncbytescat(buf,dcesortname(target->discrim));
	switch (target->discrim) {
	case CES_VAR:
	    dcedumpraw((DCEnode*)target->var,buf);
	    break;
	case CES_FCN:
	    dcedumpraw((DCEnode*)target->fcn,buf);
	    break;
	default: assert(0);
	}
    } break;

    case CES_SELECT: {
	DCEselection* sel = (DCEselection*)node;
	ncbytescat(buf," ");
	dcedumpraw((DCEnode*)sel->lhs,buf);
        if(sel->operator == CES_NIL) break;
        ncbytescat(buf,opstrings[(int)sel->operator]);
        if(nclistlength(sel->rhs) > 1)
            ncbytescat(buf,"{");
	dcedumprawlist(sel->rhs,buf);
        if(nclistlength(sel->rhs) > 1)
	    ncbytescat(buf,"}");
    } break;

    case CES_CONSTRAINT: {
	DCEconstraint* con = (DCEconstraint*)node;
        if(con->projections != NULL && nclistlength(con->projections) > 0) {
	    ncbytescat(buf,"projections=");	
            dcedumprawlist(con->projections,buf);
	}
        if(con->selections != NULL && nclistlength(con->selections) > 0) {
	    ncbytescat(buf,"selections=");	
            dcedumprawlist(con->selections,buf);
	}
    } break;

    case CES_NIL: {
	ncbytescat(buf,"<nil>");
    } break;

    default:
	assert(0);
    }
    ncbytescat(buf,RBRACE);
}

static void
dcedumprawlist(NClist* list, NCbytes* buf)
{
    int i;
    if(list == NULL || buf == NULL) return;
    ncbytescat(buf,"(");
    for(i=0;i<nclistlength(list);i++) {
	DCEnode* node = (DCEnode*)nclistget(list,i);
	if(node == NULL) continue;
	if(i>0) ncbytescat(buf,",");
	dcedumpraw((DCEnode*)node,buf);
    }
    ncbytescat(buf,")");
}

