variable.h

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/* Copyright (C) 2017-2018 Chris Piker <chris-piker@uiowa.edu>
 *
 * This file is part of libdas2, the Core Das2 C Library.
 *
 * Libdas2 is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License version 2.1 as published
 * by the Free Software Foundation.
 *
 * Libdas2 is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
 * more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * version 2.1 along with libdas2; if not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _das_variable_h_
#define _das_variable_h_

#include <das2/array.h>
#include <das2/datum.h>

#include "units.h"

#ifdef __cplusplus
extern "C" {
#endif
   
enum var_type { 
   D2V_DATUM, D2V_SEQUENCE, D2V_ARRAY, D2V_UNARY_OP, D2V_BINARY_OP
};

#define MAP_0  0, (NULL)
#define MAP_1(I)  1, (int8_t[1]){I}
#define MAP_2(I,J)  2, (int8_t[2]){I,J}
#define MAP_3(I,J,K)  3, (int8_t[3]){I,J,K}
#define MAP_4(I,J,K,L)  4, (int8_t[4]){I,J,K,L}
#define MAP_5(I,J,K,L,M)  5, (int8_t[5]){I,J,K,L,M}
#define MAP_6(I,J,K,L,M,N)  6, (int8_t[6]){I,J,K,L,M,N}
#define MAP_7(I,J,K,L,M,N,O)  7, (int8_t[7]){I,J,K,L,M,N,O}

/* Internal function for merging variable, and dimension shapes.  Different
 * rules apply for arrays to variable shape merges.
 * 
 * Combinding index rules:
 * 
 *    '*' + '-'    = '*'
 *    '*' + Number = Number      ('*' means undefined length, represented by)
 *    '-' + Number = Number      ('-' means no dependency,    negative nums )
 *    Big Number + Small Number = Small Number
 * 
 */
void das_varindex_merge(int nRank, ptrdiff_t* pDest, ptrdiff_t* pSrc);

/* Internal function for merging length in a particular dimension. */
ptrdiff_t das_varlength_merge(ptrdiff_t nLeft, ptrdiff_t nRight);

#define D2V_EXP_UNITS 0x02
#define D2V_EXP_RANGE 0x04

typedef struct das_variable{
   enum var_type vartype;  /* CONST, ARRAY, SEQUENCE, UNARY_OP, BINARY_OP ... */
   das_val_type  vt;  /* vtByte, vtText, vtTime ... */
   size_t        vsize;  /* The size in bytes of each value in the variable
                            * for strings this yields the unusual value of 
                            * sizeof(void*) */
   
   /* The units of this variable, since it is possible to create variables
    * in all kinds of ways (not just backing arrays) we have to have our
    * own units storage location.  Transforming backing arrays such that they
    * are no longer in the units they had when the variable was created will
    * NOT automatically update this variable. */
   das_units   units;  
   
   /* Reference count on this variable.  Needed to make sure it's not
    * deleted out from under us. */
   int nRef;
   
   /* Position of the first internal index.  Any array indices after
    * this point will be considered to be internal indices and will not
    * be reported in the shape function */
   int iFirstInternal;
   
   /* Get the external shape of this variable */
   int (*shape)(const struct das_variable* pThis, ptrdiff_t* pShape);
   
   /* Get the external length of this variable at a partial index */
   ptrdiff_t (*lengthIn)(
      const struct das_variable* pThis, int nIdx, ptrdiff_t* pLoc
   );
   
   bool (*get)(
      const struct das_variable* pThis, ptrdiff_t* pIdx, das_datum* pDatum
   );
   
   int (*incRef)(struct das_variable* pThis);
   
   int (*decRef)(struct das_variable* pThis);
   
   /* Write an expression (i.e. a representation) of this variable to a 
    * buffer.
    * 
    * 
    * @param uFlags - D2V_EXP_UNITS include units in the expression
    *                 D2V_EXP_RANGE include the range in the expression
    * 
    * @returns The write point to add more text to the buffer
    */
   char* (*expression)(const struct das_variable* pThis, char* sBuf, int nLen, 
                       unsigned int uFlags);
} DasVar;


DasVar* new_DasVarUnary(const char* sOp, const DasVar* pVar);

/* Internal version for use by the expression lexer */
DasVar* new_DasVarUnary_tok(int nOpTok, const DasVar* pVar);

DasVar* new_DasVarBinary(DasVar* pLeft, const char* sOp, DasVar* pRight);


DasVar* new_DasConstant(das_val_type vt, size_t sz, const void* val, das_units units);


DasVar* new_DasVarSeq(
   const char* sId, das_val_type vt, size_t vSz, const void* pMin, 
   const void* pInterval, int8_t* pMap, das_units units
);

DasVar* new_DasVarArray(DasAry* pAry, int iInternal, int8_t* pMap);

DasAry* DasVarAry_getArray(DasVar* pThis);

DasVar* new_DasVarEval(const DasVar* pVar);

bool DasVar_orthoginal(const DasVar* pThis, const DasVar* pOther);


int DasVar_shape(const DasVar* pThis, ptrdiff_t* pShape);

ptrdiff_t DasVar_lengthIn(const DasVar* pThis, int nIdx, ptrdiff_t* pLoc);

char* DasVar_toStr(const DasVar* pThis, char* sBuf, int nLen);


bool DasVar_getDatum(const DasVar* pThis, ptrdiff_t* pIdx, das_datum* pDatum);


bool DasVar_isComposite(const DasVar* pVar);



void dec_DasVar(DasVar* pThis);


#ifdef __cplusplus
}
#endif

#endif /* _das_variable_h */