/*
 * param.h - Parameters and values
 *
 * Copyright 2012 by Werner Almesberger
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */


#ifndef PARAM_H
#define	PARAM_H

#include <stdio.h>

#include "bitset.h"
#include "relop.h"


/*
 * Parameter types:
 *
 * "name"	arbitrary name
 * "set"	names from an ordered list
 * "abs"	absolute numeric value
 * "rel"	numeric value relative to another parameter
 */


struct equiv {
	const char *name;
	struct equiv *next;
};

struct names {
	struct equiv *equiv;	/* equivalent value(s) */
	struct names *next;	/* next/greater value */
};

struct param_ops;

struct format {
	const struct param_ops *ops;
	union {
		const struct names *set;
		const char *abs;	/* unit name; NULL if dimensionless */
		const struct format *rel;
	} u;
};

struct value {
	union {
		const char *s;
		struct bitset set;
		double abs;
		struct rel_value {
			double plus, minus;	/* rel: 100% = 1 */
			int fract;	/* 0: abs. offset; 1: fract. offs. */
		} rel;
	} u;
};

/*
 * When using "struct param" to store (string) variables not associated to a
 * field, then u.name contains the variable name, "op" contains the relational
 * operator (default rel_eq), and value.u.s contains the variable's value.
 *
 * If the variable is "$", then u.name is set to NULL.
 */

struct param {
	union {
		const char *name;
		const struct field *field;
	} u;
	enum relop op;
	struct value value;
	struct param *next;
};

struct param_ops {
	int (*eval)(const struct format *fmt, const char *s,
	    struct value *res);
	int (*comp)(const struct value *a, enum relop relop,
	    const struct value *b);
	void (*dump)(FILE *file, const struct format *fmt,
	    const struct value *v);
};


void register_nameset(const char *name, const struct names *set);
const struct names *find_nameset(const char *name);
const char *nameset_rev_lookup(const struct names *first_name);

int eval_name(const struct format *fmt, const char *s, struct value *res);
int eval_set(const struct format *fmt, const char *s, struct value *res);
int eval_abs(const struct format *fmt, const char *s, struct value *res);
int eval_rel(const struct format *fmt, const char *s, struct value *res);
int evaluate(const struct format *fmt, const char *s, struct value *res);

int comp_name(const struct value *a, enum relop relop, const struct value *b);
int comp_set(const struct value *a, enum relop relop, const struct value *b);
int comp_abs(const struct value *a, enum relop relop, const struct value *b);
int comp_rel(const struct value *a, enum relop relop, const struct value *b);
int compare(const struct format *fmt,
    const struct value *a, enum relop relop, const struct value *b);

void dump_name(FILE *file, const struct format *fmt, const struct value *v);
void dump_set(FILE *file, const struct format *fmt, const struct value *v);
void dump_abs(FILE *file, const struct format *fmt, const struct value *v);
void dump_rel(FILE *file, const struct format *fmt, const struct value *v);
void dump_param(FILE *file, const struct format *fmt, const struct value *v);

extern const struct param_ops param_ops_name;
extern const struct param_ops param_ops_set;
extern const struct param_ops param_ops_abs;
extern const struct param_ops param_ops_rel;

struct param *make_var(const char *name, enum relop op, const char *val);
const char *var_lookup(const struct param *vars, const char *name);
struct param *merge_vars(const struct param *a, const struct param *b);
void free_vars(struct param *vars);

#endif /* !PARAM_H */