obj.c

/*
 * obj - object handling primitives
 *
 * Copyright (C) 1999-2007,2021-2023  David I. Bell
 *
 * Calc is open software; you can redistribute it and/or modify it under
 * the terms of the version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * Calc 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.
 *
 * A copy of version 2.1 of the GNU Lesser General Public License is
 * distributed with calc under the filename COPYING-LGPL.  You should have
 * received a copy with calc; if not, write to Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Under source code control:   1990/02/15 01:48:19
 * File existed as early as:    before 1990
 *
 * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
 */
/*
 * "Object" handling primitives.
 * This simply means that user-specified routines are called to perform
 * the indicated operations.
 */


#include <stdio.h>
#include "calc.h"
#include "opcodes.h"
#include "func.h"
#include "symbol.h"
#include "str.h"
#include "strl.h"


#include "errtbl.h"
#include "banned.h"     /* include after system header <> includes */


/*
 * Types of values returned by calling object routines.
 */
#define A_VALUE 0       /* returns arbitrary value */
#define A_INT   1       /* returns integer value */
#define A_UNDEF 2       /* returns no value */

/*
 * Error handling actions for when the function is undefined.
 */
#define ERR_NONE        0       /* no special action */
#define ERR_PRINT       1       /* print element */
#define ERR_CMP 2       /* compare two values */
#define ERR_TEST        3       /* test value for nonzero */
#define ERR_POW 4       /* call generic power routine */
#define ERR_ONE 5       /* return number 1 */
#define ERR_INC 6       /* increment by one */
#define ERR_DEC 7       /* decrement by one */
#define ERR_SQUARE 8    /* square value */
#define ERR_VALUE 9     /* return value */
#define ERR_ASSIGN 10   /* assign value */


STATIC struct objectinfo {
        short args;     /* number of arguments */
        short retval;   /* type of return value */
        short error;    /* special action on errors */
        char *name;     /* name of function to call */
        char *comment;  /* useful comment if any */
} objectinfo[] = {
        {1, A_UNDEF, ERR_PRINT,
         "print",       "print value, default prints elements"},
        {1, A_VALUE, ERR_ONE,
         "one", "multiplicative identity, default is 1"},
        {1, A_INT,   ERR_TEST,
         "test", "logical test (false,true => 0,1), default tests elements"},
        {2, A_VALUE, ERR_NONE,
         "add", NULL},
        {2, A_VALUE, ERR_NONE,
         "sub", NULL},
        {1, A_VALUE, ERR_NONE,
         "neg", "negative"},
        {2, A_VALUE, ERR_NONE,
         "mul", NULL},
        {2, A_VALUE, ERR_NONE,
         "div", "non-integral division"},
        {1, A_VALUE, ERR_NONE,
         "inv", "multiplicative inverse"},
        {2, A_VALUE, ERR_NONE,
         "abs", "absolute value within given error"},
        {1, A_VALUE, ERR_NONE,
         "norm", "square of absolute value"},
        {1, A_VALUE, ERR_NONE,
         "conj", "conjugate"},
        {2, A_VALUE, ERR_POW,
         "pow", "integer power, default does multiply, square, inverse"},
        {1, A_VALUE, ERR_NONE,
         "sgn", "sign of value (-1, 0, 1)"},
        {2, A_INT,   ERR_CMP,
         "cmp", "equality (equal,nonequal => 0,1), default tests elements"},
        {2, A_VALUE, ERR_NONE,
         "rel", "relative order, positive for >, etc."},
        {3, A_VALUE, ERR_NONE,
         "quo", "integer quotient"},
        {3, A_VALUE, ERR_NONE,
         "mod", "remainder of division"},
        {1, A_VALUE, ERR_NONE,
         "int", "integer part"},
        {1, A_VALUE, ERR_NONE,
         "frac", "fractional part"},
        {1, A_VALUE, ERR_INC,
         "inc", "increment, default adds 1"},
        {1, A_VALUE, ERR_DEC,
         "dec", "decrement, default subtracts 1"},
        {1, A_VALUE, ERR_SQUARE,
         "square", "default multiplies by itself"},
        {2, A_VALUE, ERR_NONE,
         "scale", "multiply by power of 2"},
        {2, A_VALUE, ERR_NONE,
         "shift", "shift left by n bits (right if negative)"},
        {3, A_VALUE, ERR_NONE,
         "round", "round to given number of decimal places"},
        {3, A_VALUE, ERR_NONE,
         "bround", "round to given number of binary places"},
        {3, A_VALUE, ERR_NONE,
         "root", "root of value within given error"},
        {3, A_VALUE, ERR_NONE,
         "sqrt", "square root within given error"},
        {2, A_VALUE, ERR_NONE,
         "or",  "bitwise or"},
        {2, A_VALUE, ERR_NONE,
         "and", "bitwise and"},
        {1, A_VALUE, ERR_NONE,
         "not", "logical not"},
        {1, A_VALUE, ERR_NONE,
         "fact", "factorial or postfix !"},
        {1, A_VALUE, ERR_VALUE,
         "min", "value for min(...)"},
        {1, A_VALUE, ERR_VALUE,
         "max", "value for max(...)"},
        {1, A_VALUE, ERR_VALUE,
         "sum", "value for sum(...)"},
        {2, A_UNDEF, ERR_ASSIGN,
         "assign", "assign, defaults to a = b"},
        {2, A_VALUE, ERR_NONE,
         "xor", "value for binary ~"},
        {1, A_VALUE, ERR_NONE,
         "comp", "value for unary ~"},
        {1, A_VALUE, ERR_NONE,
         "content", "unary hash op"},
        {2, A_VALUE, ERR_NONE,
         "hashop",  "binary hash op"},
        {1, A_VALUE, ERR_NONE,
         "backslash", "unary backslash op"},
        {2, A_VALUE, ERR_NONE,
         "setminus", "binary backslash op"},
        {1, A_VALUE, ERR_NONE,
         "plus", "unary + op"},
        {0, 0, 0,
         NULL, NULL}
};


STATIC STRINGHEAD objectnames;  /* names of objects */
STATIC STRINGHEAD elements;     /* element names for parts of objects */
STATIC OBJECTACTIONS **objects; /* table of actions for objects */

#define OBJALLOC 16
STATIC long maxobjcount = 0;

S_FUNC VALUE objpowi(VALUE *vp, NUMBER *q);
S_FUNC bool objtest(OBJECT *op);
S_FUNC bool objcmp(OBJECT *op1, OBJECT *op2);
S_FUNC void objprint(OBJECT *op);


/*
 * Show all the routine names available for objects.
 */
void
showobjfuncs(void)
{
        register struct objectinfo *oip;

        printf("\nThe following object routines are definable.\n");
        printf("Note: xx represents the actual object type name.\n\n");
        printf("Name    Args    Comments\n");
        for (oip = objectinfo; oip->name; oip++) {
                printf("xx_%-8s %d      %s\n", oip->name, oip->args,
                        oip->comment ? oip->comment : "");
        }
        printf("\n");
}


/*
 * Call the appropriate user-defined routine to handle an object action.
 * Returns the value that the routine returned.
 */
VALUE
objcall(int action, VALUE *v1, VALUE *v2, VALUE *v3)
{
        FUNC *fp;               /* function to call */
        STATIC OBJECTACTIONS *oap; /* object to call for */
        struct objectinfo *oip; /* information about action */
        long index;             /* index of function (negative if undefined) */
        VALUE val;              /* return value */
        VALUE tmp;              /* temp value */
        char name[SYMBOLSIZE+1+1];      /* full name of user routine to call */
        size_t namestr_len;     /* length of the namestr() return string */
        char *namestr_ret;      /* namestr() return string */
        size_t opi_name_len;    /* length of the oip name */

        /* initialize name */
        memset(name, 0, sizeof(name));

        /* initialize VALUEs */
        val.v_subtype = V_NOSUBTYPE;
        tmp.v_subtype = V_NOSUBTYPE;

        if ((unsigned)action > OBJ_MAXFUNC) {
                math_error("Illegal action for object call");
                not_reached();
        }
        oip = &objectinfo[action];
        if (v1->v_type == V_OBJ) {
                oap = v1->v_obj->o_actions;
        } else if (v2->v_type == V_OBJ) {
                oap = v2->v_obj->o_actions;
        } else {
                math_error("Object routine called with non-object");
                not_reached();
        }
        index = oap->oa_indices[action];
        if (index < 0) {
                namestr_ret = namestr(&objectnames, oap->oa_index);
                if (namestr_ret == NULL) {
                        math_error("namestr returned NULL!!!");
                        not_reached();
                }
                namestr_len = strlen(namestr_ret);
                opi_name_len = strlen(oip->name);
                if (namestr_len > (size_t)SYMBOLSIZE-1-opi_name_len) {
                        math_error("namestr returned a strong too long!!!");
                        not_reached();
                }
                name[0] = '\0';
                strlcpy(name, namestr_ret, namestr_len+1);
                strlcat(name, "_", sizeof(name));
                strlcat(name, oip->name, sizeof(name));
                index = adduserfunc(name);
                oap->oa_indices[action] = index;
        }
        fp = NULL;
        if (index >= 0)
                fp = findfunc(index);
        if (fp == NULL) {
                switch (oip->error) {
                case ERR_PRINT:
                        objprint(v1->v_obj);
                        val.v_type = V_NULL;
                        break;
                case ERR_CMP:
                        val.v_type = V_INT;
                        if (v1->v_type != v2->v_type) {
                                val.v_int = 1;
                                return val;
                        }
                        val.v_int = objcmp(v1->v_obj, v2->v_obj);
                        break;
                case ERR_TEST:
                        val.v_type = V_INT;
                        val.v_int = objtest(v1->v_obj);
                        break;
                case ERR_POW:
                        if (v2->v_type != V_NUM) {
                                math_error("Non-real power");
                                not_reached();
                        }
                        val = objpowi(v1, v2->v_num);
                        break;
                case ERR_ONE:
                        val.v_type = V_NUM;
                        val.v_num = qlink(&_qone_);
                        break;
                case ERR_INC:
                        tmp.v_type = V_NUM;
                        tmp.v_num = &_qone_;
                        val = objcall(OBJ_ADD, v1, &tmp, NULL_VALUE);
                        break;
                case ERR_DEC:
                        tmp.v_type = V_NUM;
                        tmp.v_num = &_qone_;
                        val = objcall(OBJ_SUB, v1, &tmp, NULL_VALUE);
                        break;
                case ERR_SQUARE:
                        val = objcall(OBJ_MUL, v1, v1, NULL_VALUE);
                        break;
                case ERR_VALUE:
                        copyvalue(v1, &val);
                        break;
                case ERR_ASSIGN:
                        copyvalue(v2, &tmp);
                        tmp.v_subtype |= v1->v_subtype;
                        freevalue(v1);
                        *v1 = tmp;
                        val.v_type = V_NULL;
                        break;
                default:
                        math_error("Function \"%s\" is undefined",
                                    namefunc(index));
                        not_reached();
                }
                return val;
        }
        switch (oip->args) {
        case 0:
                break;
        case 1:
                ++stack;
                stack->v_addr = v1;
                stack->v_type = V_ADDR;
                break;
        case 2:
                ++stack;
                stack->v_addr = v1;
                stack->v_type = V_ADDR;
                ++stack;
                stack->v_addr = v2;
                stack->v_type = V_ADDR;
                break;
        case 3:
                ++stack;
                stack->v_addr = v1;
                stack->v_type = V_ADDR;
                ++stack;
                stack->v_addr = v2;
                stack->v_type = V_ADDR;
                ++stack;
                stack->v_addr = v3;
                stack->v_type = V_ADDR;
                break;
        default:
                math_error("Bad number of args to calculate");
                not_reached();
        }
        calculate(fp, oip->args);
        switch (oip->retval) {
        case A_VALUE:
                return *stack--;
        case A_UNDEF:
                freevalue(stack--);
                val.v_type = V_NULL;
                break;
        case A_INT:
                if ((stack->v_type != V_NUM) || qisfrac(stack->v_num)) {
                        math_error("Integer return value required");
                        not_reached();
                }
                index = qtoi(stack->v_num);
                qfree(stack->v_num);
                stack--;
                val.v_type = V_INT;
                val.v_int = index;
                break;
        default:
                math_error("Bad object return");
                not_reached();
        }
        return val;
}


/*
 * Print the elements of an object in short and unambiguous format.
 * This is the default routine if the user's is not defined.
 *
 * given:
 *      op              object being printed
 */
S_FUNC void
objprint(OBJECT *op)
{
        int count;              /* number of elements */
        int i;                  /* index */

        count = op->o_actions->oa_count;
        math_fmt("obj %s {", namestr(&objectnames, op->o_actions->oa_index));
        for (i = 0; i < count; i++) {
                if (i)
                        math_str(", ");
                printvalue(&op->o_table[i], PRINT_SHORT | PRINT_UNAMBIG);
        }
        math_chr('}');
}


/*
 * Test an object for being "nonzero".
 * This is the default routine if the user's is not defined.
 * Returns true if any of the elements are "nonzero".
 */
S_FUNC bool
objtest(OBJECT *op)
{
        int i;                  /* loop counter */

        i = op->o_actions->oa_count;
        while (--i >= 0) {
                if (testvalue(&op->o_table[i]))
                        return true;
        }
        return false;
}


/*
 * Compare two objects for equality, returning true if they differ.
 * This is the default routine if the user's is not defined.
 * For equality, all elements must be equal.
 */
S_FUNC bool
objcmp(OBJECT *op1, OBJECT *op2)
{
        int i;                  /* loop counter */

        if (op1->o_actions != op2->o_actions)
                return true;
        i = op1->o_actions->oa_count;
        while (--i >= 0) {
                if (comparevalue(&op1->o_table[i], &op2->o_table[i]))
                        return true;
        }
        return false;
}


/*
 * Raise an object to an integral power.
 * This is the default routine if the user's is not defined.
 * Negative powers mean the positive power of the inverse.
 * Zero means the multiplicative identity.
 *
 * given:
 *      vp              value to be powered
 *      q               power to raise number to
 */
S_FUNC VALUE
objpowi(VALUE *vp, NUMBER *q)
{
        VALUE res, tmp;
        long power;             /* power to raise to */
        FULL bit;               /* current bit value */

        if (qisfrac(q)) {
                math_error("Raising object to non-integral power");
                not_reached();
        }
        if (zge31b(q->num)) {
                math_error("Raising object to very large power");
                not_reached();
        }
        power = ztolong(q->num);
        if (qisneg(q))
                power = -power;
        /*
         * Handle some low powers specially
         */
        if ((power <= 2) && (power >= -2)) {
                switch ((int) power) {
                case 0:
                        return objcall(OBJ_ONE, vp, NULL_VALUE, NULL_VALUE);
                case 1:
                        res.v_obj = objcopy(vp->v_obj);
                        res.v_type = V_OBJ;
                        res.v_subtype = V_NOSUBTYPE;
                        return res;
                case -1:
                        return objcall(OBJ_INV, vp, NULL_VALUE, NULL_VALUE);
                case 2:
                        return objcall(OBJ_SQUARE, vp, NULL_VALUE, NULL_VALUE);
                }
        }
        if (power < 0)
                power = -power;
        /*
         * Compute the power by squaring and multiplying.
         * This uses the left to right method of power raising.
         */
        bit = TOPFULL;
        while ((bit & power) == 0)
                bit >>= 1L;
        bit >>= 1L;
        res = objcall(OBJ_SQUARE, vp, NULL_VALUE, NULL_VALUE);
        if (bit & power) {
                tmp = objcall(OBJ_MUL, &res, vp, NULL_VALUE);
                objfree(res.v_obj);
                res = tmp;
        }
        bit >>= 1L;
        while (bit) {
                tmp = objcall(OBJ_SQUARE, &res, NULL_VALUE, NULL_VALUE);
                objfree(res.v_obj);
                res = tmp;
                if (bit & power) {
                        tmp = objcall(OBJ_MUL, &res, vp, NULL_VALUE);
                        objfree(res.v_obj);
                        res = tmp;
                }
                bit >>= 1L;
        }
        if (qisneg(q)) {
                tmp = objcall(OBJ_INV, &res, NULL_VALUE, NULL_VALUE);
                objfree(res.v_obj);
                return tmp;
        }
        return res;
}


/*
 * Define a (possibly) new class of objects.
 * The list of indexes for the element names is also specified here,
 * and the number of elements defined for the object.
 *
 * given:
 *      name            name of object type
 *      indices         table of indices for elements
 *      count           number of elements defined for the object
 */
int
defineobject(char *name, int indices[], int count)
{
        OBJECTACTIONS *oap;     /* object definition structure */
        STRINGHEAD *hp;
        OBJECTACTIONS **newobjects;
        int index;

        hp = &objectnames;
        if (hp->h_list == NULL)
                initstr(hp);
        index = findstr(hp, name);
        if (index >= 0) {
                /*
                 * Object is already defined.  Give an error unless this
                 * new definition is exactly the same as the old one.
                 */
                oap = objects[index];
                if (oap->oa_count == count) {
                        for (index = 0; ; index++) {
                                if (index >= count)
                                        return 0;
                                if (oap->oa_elements[index] != indices[index])
                                        break;
                        }
                }
                return 1;
        }

        if (hp->h_count >= maxobjcount) {
                if (maxobjcount == 0) {
                        newobjects = (OBJECTACTIONS **) malloc(
                                OBJALLOC * sizeof(OBJECTACTIONS *));
                        maxobjcount = OBJALLOC;
                } else {
                        maxobjcount += OBJALLOC;
                        newobjects = (OBJECTACTIONS **) realloc(objects,
                                maxobjcount * sizeof(OBJECTACTIONS *));
                }
                if (newobjects == NULL) {
                        math_error("Allocation failure for new object type");
                        not_reached();
                }
                objects = newobjects;
        }

        oap = (OBJECTACTIONS *) malloc(objectactionsize(count));
        if (oap == NULL) {
                math_error("Cannot allocate object type #0");
                not_reached();
        }
        name = addstr(hp, name);
        if (name == NULL) {
                math_error("Cannot allocate object type #1");
                not_reached();
        }
        oap->oa_count = count;
        for (index = OBJ_MAXFUNC; index >= 0; index--)
                oap->oa_indices[index] = -1;
        for (index = 0; index < count; index++)
                oap->oa_elements[index] = indices[index];
        index = findstr(hp, name);
        oap->oa_index = index;
        objects[index] = oap;
        return 0;
}


/*
 * Check an object name to see if it is currently defined.
 * If so, the index for the object type is returned.
 * If the object name is currently unknown, then -1 is returned.
 */
int
checkobject(char *name)
{
        STRINGHEAD *hp;

        hp = &objectnames;
        if (hp->h_list == NULL)
                return -1;
        return findstr(hp, name);
}


/*
 * Define a (possibly) new element name for an object.
 * Returns an index which identifies the element name.
 */
int
addelement(char *name)
{
        STRINGHEAD *hp;
        int index;

        hp = &elements;
        if (hp->h_list == NULL)
                initstr(hp);
        index = findstr(hp, name);
        if (index >= 0)
                return index;
        if (addstr(hp, name) == NULL) {
                math_error("Cannot allocate element name");
                not_reached();
        }
        return findstr(hp, name);
}


/*
 * Return the index which identifies an element name.
 * Returns minus one if the element name is unknown.
 *
 * given:
 *      name            element name
 */
int
findelement(char *name)
{
        if (elements.h_list == NULL)
                return -1;
        return findstr(&elements, name);
}


/*
 * Returns the name of object type with specified index
 */
char *
objtypename(unsigned long index)
{
        return namestr(&objectnames, (long)index);
}


/*
 * Return the value table offset to be used for an object element name.
 * This converts the element index from the element table into an offset
 * into the object value array.  Returns -1 if the element index is unknown.
 */
int
objoffset(OBJECT *op, long index)
{
        register OBJECTACTIONS *oap;
        int offset;                     /* offset into value array */

        oap = op->o_actions;
        for (offset = oap->oa_count - 1; offset >= 0; offset--) {
                if (oap->oa_elements[offset] == index)
                        return offset;
        }
        return -1;
}


/*
 * Allocate a new object structure with the specified index.
 */
OBJECT *
objalloc(long index)
{
        OBJECTACTIONS *oap;
        OBJECT *op;
        VALUE *vp;
        int i;

        if (index < 0 || index > maxobjcount) {
                math_error("Allocating bad object index");
                not_reached();
        }
        oap = objects[index];
        if (oap == NULL) {
                math_error("Object type not defined");
                not_reached();
        }
        i = oap->oa_count;
        if (i < USUAL_ELEMENTS)
                i = USUAL_ELEMENTS;
        if (i == USUAL_ELEMENTS)
                op = (OBJECT *) malloc(sizeof(OBJECT));
        else
                op = (OBJECT *) malloc(objectsize(i));
        if (op == NULL) {
                math_error("Cannot allocate object");
                not_reached();
        }
        op->o_actions = oap;
        vp = op->o_table;
        for (i = oap->oa_count; i-- > 0; vp++) {
                vp->v_num = qlink(&_qzero_);
                vp->v_type = V_NUM;
                vp->v_subtype = V_NOSUBTYPE;
        }
        return op;
}


/*
 * Free an object structure.
 */
void
objfree(OBJECT *op)
{
        VALUE *vp;
        int i;

        vp = op->o_table;
        for (i = op->o_actions->oa_count; i-- > 0; vp++) {
                if (vp->v_type == V_NUM) {
                        qfree(vp->v_num);
                } else {
                        freevalue(vp);
                }
        }
        if (op->o_actions->oa_count <= USUAL_ELEMENTS)
                free(op);
        else
                free((char *) op);
}


/*
 * Copy an object value
 */
OBJECT *
objcopy(OBJECT *op)
{
        VALUE *v1, *v2;
        OBJECT *np;
        int i;

        i = op->o_actions->oa_count;
        if (i < USUAL_ELEMENTS)
                i = USUAL_ELEMENTS;
        if (i == USUAL_ELEMENTS)
                np = (OBJECT *) malloc(sizeof(OBJECT));
        else
                np = (OBJECT *) malloc(objectsize(i));
        if (np == NULL) {
                math_error("Cannot allocate object");
                not_reached();
        }
        np->o_actions = op->o_actions;
        v1 = op->o_table;
        v2 = np->o_table;
        for (i = op->o_actions->oa_count; i-- > 0; v1++, v2++) {
                copyvalue(v1, v2);
        }
        return np;
}


/*
 * Show object types that have been defined.
 */
void
showobjtypes(void)
{
        STRINGHEAD *hp;
        OBJECTACTIONS *oap;
        STRINGHEAD *ep;
        int index, i;

        hp = &objectnames;
        ep = &elements;
        if (hp->h_count == 0) {
                printf("No object types defined\n");
                return;
        }
        for (index = 0; index < hp->h_count; index++) {
                oap = objects[index];
                printf("\t%s\t{", namestr(&objectnames, index));
                for (i = 0; i < oap->oa_count; i++) {
                        if (i) printf(",");
                        printf("%s", namestr(ep, oap->oa_elements[i]));
                }
                printf("}\n");
        }

}


/* END CODE */