/* Runtime types.

Copyright (C) 2015, 2016, 2017 Paul Boddie <paul@boddie.org.uk>

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 3 of the License, or (at your option) any later

version.

This program 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 General Public License for more

details.

You should have received a copy of the GNU General Public License along with

this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef __TYPES_H__

#define __TYPES_H__

/* Define code and position types, populated by enum values defined for each

   program specifically. */

#include <stdint.h>

/* Include the special instance position value. The pos member of __obj refers

   to the special type attribute for classes, indicating which position holds

   the attribute describing the class type. For instances, it is set to the same

   attribute position as __class__ and is defined in the following file. */

#include "instancepos.h"

typedef uint16_t __code;

typedef uint16_t __pos;

typedef uint16_t __pcode;

typedef uint16_t __ppos;

/* Attribute tables are lists of codes confirming the presence of attributes. */

typedef struct __table

{

    const __pos size;

    const __code attrs[];

} __table;

/* Parameter tables are lists of codes confirming the presence of parameters, as

   well as the positions of those parameters in the list for a given function.

*/

typedef struct __param

{

    __code code;

    __pos pos;

} __param;

typedef struct __ptable

{

    const __ppos min, max, size;

    const __param params[];

} __ptable;

/* Attributes are values referring to objects or encoding other information.

   Objects are collections of attributes.

   Object references are references to tables and collections of attributes.

   Attribute references are references to single attributes. */

typedef struct __obj __obj;

typedef struct __fragment __fragment;

typedef union __attr __attr;

typedef __obj * __ref;

typedef union __attr

{

    /* General attribute members. */

    __ref value;                /* attribute value */

    int intvalue;               /* integer value data ((integer << 1) | 1) */

    /* Special case attribute members. */

    const __ptable * ptable;    /* parameter table */

    struct {

        __pcode code;           /* parameter table code for key */

        __ppos pos;             /* parameter table position for key */

    };

    __attr (*fn)();             /* callable details */

    float floatvalue;          	/* floating point value */

    char * strvalue;            /* string value */

    __fragment * seqvalue;      /* sequence data */

    void * datavalue;           /* object-specific data */

} __attr;

typedef struct __obj

{

    const __table * table;      /* attribute table */

    __ppos pos;                 /* position of attribute indicating class */

    __attr attrs[];             /* attributes */

} __obj;

#define __INSTANCE_SIZE(NUMBER) ((NUMBER) * sizeof(__attr) + sizeof(__table *) + sizeof(__ppos))

/* Fragments are simple collections of attributes employed by sequence types.

   They provide the basis of lists and tuples. */

typedef struct __fragment

{

    unsigned int size, capacity;

    __attr attrs[];

} __fragment;

#define __FRAGMENT_SIZE(NUMBER) ((NUMBER) * sizeof(__attr) + 2 * sizeof(unsigned int))

/* Attribute interpretation. */

#define __INTEGER(ATTR) ((ATTR).intvalue % 2)

/* Attribute value setting. */

#define __ATTRVALUE(VALUE) ((__attr) {.value=VALUE})

#define __NULL __ATTRVALUE(0)

#define __SETNULL(ATTR) ((ATTR).value = 0)

/* Attribute as instance setting. */

#define __INTVALUE(VALUE) ((__attr) {.intvalue=((VALUE) << 1) | 1})

#define __TOINT(ATTR) ((ATTR).intvalue >> 1)

#define __MAXINT ((1 << ((sizeof(__attr) * 8) - 2)) - 1)

#define __MININT (-(1 << ((sizeof(__attr) * 8) - 2)))

/* Argument lists. */

#define __ARGS(...) ((__attr[]) {__VA_ARGS__})

#define __KWARGS(...) ((__param[]) {__VA_ARGS__})

/* Attribute codes and positions for attribute names. */

#define __ATTRCODE(ATTRNAME) __code_##ATTRNAME

#define __ATTRPOS(ATTRNAME) __pos_##ATTRNAME

#define __PARAMCODE(PARAMNAME) __pcode_##PARAMNAME

#define __PARAMPOS(PARAMNAME) __ppos_##PARAMNAME

#endif /* __TYPES_H__ */