/****************************************************************************
 * RRDtool 1.2.23  Copyright by Tobi Oetiker, 1997-2007
 ****************************************************************************
 * rrd_rpncalc.h  RPN calculator functions
 ****************************************************************************/
#ifndef _RRD_RPNCALC_H
#define _RRD_RPNCALC_H

/* WARNING: if new operators are added, they MUST be added at the very end of the list.
 * This is because COMPUTE (CDEF) DS store OP nodes by number (name is not
 * an option due to limited par array size). OP nodes must have the same
 * numeric values, otherwise the stored numbers will mean something different. */
enum op_en {OP_NUMBER=0,OP_VARIABLE,OP_INF,OP_PREV,OP_NEGINF,
	    OP_UNKN,OP_NOW,OP_TIME,OP_ADD,OP_MOD,OP_SUB,OP_MUL,
	    OP_DIV,OP_SIN, OP_DUP, OP_EXC, OP_POP,
	    OP_COS,OP_LOG,OP_EXP,OP_LT,OP_LE,OP_GT,OP_GE,OP_EQ,OP_IF,
	    OP_MIN,OP_MAX,OP_LIMIT, OP_FLOOR, OP_CEIL,
	    OP_UN,OP_END,OP_LTIME,OP_NE,OP_ISINF,OP_PREV_OTHER,OP_COUNT,
           OP_ATAN,OP_SQRT,OP_SORT,OP_REV,OP_TREND,
           OP_ATAN2,OP_RAD2DEG,OP_DEG2RAD,
           OP_AVG,OP_ABS};

typedef struct rpnp_t {
    enum op_en   op;
    double val; /* value for a OP_NUMBER */
    long ptr; /* pointer into the gdes array for OP_VAR */
    double *data; /* pointer to the current value from OP_VAR DAS*/
    long ds_cnt;   /* data source count for data pointer */
    long step; /* time step for OP_VAR das */
} rpnp_t;

/* a compact representation of rpnp_t for computed data sources */
typedef struct rpn_cdefds_t {
    char op;  /* rpn operator type */
    short val; /* used by OP_NUMBER and OP_VARIABLE */
} rpn_cdefds_t;

/* limit imposed by sizeof(rpn_cdefs_t) and rrd.ds_def.par */
#define DS_CDEF_MAX_RPN_NODES 26 

typedef struct rpnstack_t {
    double *s;
    long dc_stacksize;
    long dc_stackblock;
} rpnstack_t;

void rpnstack_init(rpnstack_t *rpnstack);
void rpnstack_free(rpnstack_t *rpnstack);

void parseCDEF_DS(const char *def, rrd_t *rrd, int ds_idx);
long lookup_DS(void *rrd_vptr, char *ds_name);

short rpn_compact(rpnp_t *rpnp,rpn_cdefds_t **rpnc,short *count);
rpnp_t * rpn_expand(rpn_cdefds_t *rpnc);
void rpn_compact2str(rpn_cdefds_t *rpnc,ds_def_t *ds_def,char **str);
rpnp_t * rpn_parse(void *key_hash,const char *const expr, long (*lookup)(void *,char *));
short rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx, rrd_value_t *output, int output_idx);

#endif