src/common/caldefn.c

#ifndef lint
static const char       RCSid[] = "$Id: caldefn.c,v 2.35 2023/09/26 00:14:02 greg Exp $";
#endif
/*
 *  Store variable definitions.
 *
 *  7/1/85  Greg Ward
 *
 *  11/11/85  Added conditional compiles (OUTCHAN) for control output.
 *
 *  4/2/86  Added conditional compiles for function definitions (FUNCTION).
 *
 *  1/15/88  Added clock for caching of variable values.
 *
 *  11/16/88  Added VARDEF structure for hard linking.
 *
 *  5/31/90  Added conditional compile (REDEFW) for redefinition warning.
 *
 *  4/23/91  Added ':' assignment for constant expressions
 *
 *  8/7/91  Added optional context path to append to variable names
 *
 *  5/17/2001  Fixed clock counter wrapping behavior
 *
 *  2/19/03     Eliminated conditional compiles in favor of esupport extern.
 */

#include "copyright.h"

#include  <ctype.h>

#include  "rterror.h"
#include  "rtio.h"
#include  "rtmisc.h"
#include  "calcomp.h"

#ifndef  NHASH
#define  NHASH          521             /* hash size (a prime!) */
#endif

#define  hash(s)        (shash(s)%NHASH)

#define  newnode()      (EPNODE *)ecalloc(1, sizeof(EPNODE))

static double  dvalue(char  *name, EPNODE *d);

#define  MAXCLOCK       (1L<<31)        /* clock wrap value */

unsigned long  eclock = 0;              /* value storage timer */

#define  MAXCNTX        1023            /* maximum context length */

static char  context[MAXCNTX+1];        /* current context path */

static VARDEF  *hashtbl[NHASH];         /* definition list */
static int  htndx;                      /* index for */         
static VARDEF  *htpos;                  /* ...dfirst() and */
static EPNODE  *ochpos;                 /* ...dnext */
static EPNODE  *outchan;

EPNODE  *curfunc = NULL;


void
fcompile(                       /* get definitions from a file */
        char  *fname
)
{
    FILE  *fp;

    if (fname == NULL)
        fp = stdin;
    else if ((fp = fopen(fname, "r")) == NULL) {
        eputs(fname);
        eputs(": cannot open\n");
        quit(1);
    }
#ifdef getc_unlocked                    /* avoid stupid semaphores */
    flockfile(fp);
#endif
   initfile(fp, fname, 0);
    while (nextc != EOF)
        getstatement();
    if (fname != NULL)
        fclose(fp);
#ifdef getc_unlocked
    else
        funlockfile(fp);
#endif
}


void
scompile(               /* get definitions from a string */
        char  *str,
        char  *fn,
        int  ln
)
{
    initstr(str, fn, ln);
    while (nextc != EOF)
        getstatement();
}


double
varvalue(                       /* return a variable's value */
        char  *vname
)
{
    return(dvalue(vname, dlookup(vname)));
}


double
evariable(                      /* evaluate a variable */
        EPNODE  *ep
)
{
    VARDEF  *dp = ep->v.ln;

    return(dvalue(dp->name, dp->def));
}


void
varset(         /* set a variable's value */
        char  *vname,
        int  assign,
        double  val
)
{
    char  *qname;
    EPNODE  *ep1, *ep2;
                                        /* get qualified name */
    qname = qualname(vname, 0);
                                        /* check for quick set */
    if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM &&
                (ep1->type == ':') <= (assign == ':')) {
        ep2 = ep1->v.kid->sibling;
        if (ep2->type == NUM) {
            ep2->v.num = val;
            ep1->type = assign;
            return;
        }
    }
    if (ep1 != NULL && esupport&E_REDEFW) {
        wputs(qname);
        if (ep1->type == ':')
            wputs(": reset constant expression\n");
        else
            wputs(": reset expression\n");
    }
                                        /* hand build definition */
    ep1 = newnode();
    ep1->type = assign;
    ep2 = newnode();
    ep2->type = SYM;
    ep2->v.name = savestr(vname);
    addekid(ep1, ep2);
    ep2 = newnode();
    ep2->type = NUM;
    ep2->v.num = val;
    addekid(ep1, ep2);
    if (assign == ':')
        dremove(qname);
    else
        dclear(qname);
    dpush(qname, ep1);
}


void
dclear(                 /* delete variable definitions of name */
        char  *name
)
{
    EPNODE  *ep;

    while ((ep = dpop(name)) != NULL) {
        if (ep->type == ':') {
            dpush(name, ep);            /* don't clear constants */
            return;
        }
        epfree(ep);
    }
}


void
dremove(                        /* delete all definitions of name */
        char  *name
)
{
    EPNODE  *ep;

    while ((ep = dpop(name)) != NULL)
        epfree(ep);
}


int
vardefined(     /* return '=' or ':' if variable/constant defined */
        char  *name
)
{
    EPNODE  *dp = dlookup(name);

    if (dp == NULL || dp->v.kid->type != SYM)
        return(0);

    return(dp->type);
}


char *
calcontext(                     /* set a new context path */
        char  *ctx
)
{
    char  *cpp;

    if (ctx == NULL)
        return(context);                /* just asking */
    while (*ctx == CNTXMARK)
        ctx++;                          /* skip past marks */
    if (!*ctx) {
        context[0] = '\0';              /* empty means clear context */
        return(context);
    }
    cpp = context;                      /* start context with mark */
    *cpp++ = CNTXMARK;
    do {                                /* carefully copy new context */
        if (cpp >= context+MAXCNTX)
            break;                      /* just copy what we can */
        if (isid(*ctx))
            *cpp++ = *ctx++;
        else {
            *cpp++ = '_'; ctx++;
        }
    } while (*ctx);
    while (cpp[-1] == CNTXMARK)         /* cannot end in context mark */
        cpp--;
    *cpp = '\0';
    return(context);
}


char *
pushcontext(            /* push on another context */
        char  *ctx
)
{
    char  oldcontext[MAXCNTX+1];
    int  n;

    strcpy(oldcontext, context);        /* save old context */
    calcontext(ctx);                    /* set new context */
    n = strlen(context);                /* tack on old */
    if (n+strlen(oldcontext) > MAXCNTX) {
        strncpy(context+n, oldcontext, MAXCNTX-n);
        context[MAXCNTX] = '\0';
    } else
        strcpy(context+n, oldcontext);
    return(context);
}


char *
popcontext(void)                        /* pop off top context */
{
    char  *cp1, *cp2;

    if (!context[0])                    /* nothing left to pop */
        return(context);
    cp2 = context;                      /* find mark */
    while (*++cp2 && *cp2 != CNTXMARK)
        ;
    cp1 = context;                      /* copy tail to front */
    while ( (*cp1++ = *cp2++) )
        ;
    return(context);
}


char *
qualname(               /* get qualified name */
        char  *nam,
        int  lvl
)
{
    static char  nambuf[RMAXWORD+1];
    char  *cp = nambuf, *cpp;
                                /* check for explicit local */
    if (*nam == CNTXMARK) {
        if (lvl > 0)            /* only action is to refuse search */
            return(NULL);
        nam++;
    } else if (nam == nambuf)   /* check for repeat call */
        return(lvl > 0 ? NULL : nam);
                                /* copy name to static buffer */
    while (*nam) {
        if (cp >= nambuf+RMAXWORD)
                goto toolong;
        *cp++ = *nam++;
    }
                                /* check for explicit global */
    if (cp > nambuf && cp[-1] == CNTXMARK) {
        if (lvl > 0)
            return(NULL);
        *--cp = '\0';
        return(nambuf);         /* already qualified */
    }
    cpp = context;              /* else skip the requested levels */
    while (lvl-- > 0) {
        if (!*cpp)
            return(NULL);       /* return NULL if past global level */
        while (*++cpp && *cpp != CNTXMARK)
            ;
    }
    while (*cpp) {              /* copy context to static buffer */
        if (cp >= nambuf+RMAXWORD)
            goto toolong;
        *cp++ = *cpp++;
    }
toolong:
    *cp = '\0';
    return(nambuf);             /* return qualified name */
}


int
incontext(                      /* is qualified name in current context? */
        char  *qn
)
{
    if (!context[0])                    /* global context accepts all */
        return(1);
    while (*qn && *qn != CNTXMARK)      /* find context mark */
        qn++;
    return(!strcmp(qn, context));
}


void
chanout(                        /* set output channels */
        void  (*cs)(int n, double v)
)
{
    EPNODE  *ep;

    for (ep = outchan; ep != NULL; ep = ep->sibling)
        (*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling));

}


void
dcleanup(               /* clear definitions (0->vars,1->output,2->consts) */
        int  lvl
)
{
    int  i;
    VARDEF  *vp;
    EPNODE  *ep;
                                /* if context is global, clear all */
    for (i = 0; i < NHASH; i++)
        for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
            if (incontext(vp->name)) {
                if (lvl >= 2)
                    dremove(vp->name);
                else
                    dclear(vp->name);
            }
    if (lvl >= 1)
        while (outchan != NULL) {
            ep = outchan;
            outchan = ep->sibling;
            ep->sibling = NULL;
            epfree(ep);
        }
}


EPNODE *
dlookup(                        /* look up a definition */
        char  *name
)
{
    VARDEF  *vp;
    
    if ((vp = varlookup(name)) == NULL)
        return(NULL);
    return(vp->def);
}


VARDEF *
varlookup(                      /* look up a variable */
        char  *name
)
{
    int  lvl = 0;
    char  *qname;
    VARDEF  *vp;
                                /* find most qualified match */
    while ((qname = qualname(name, lvl++)) != NULL)
        for (vp = hashtbl[hash(qname)]; vp != NULL; vp = vp->next)
            if (!strcmp(vp->name, qname))
                return(vp);
    return(NULL);
}


VARDEF *
varinsert(                      /* get a link to a variable */
        char  *name
)
{
    VARDEF  *vp;
    int  hv;
    
    if ((vp = varlookup(name)) != NULL) {
        vp->nlinks++;
        return(vp);
    }
    vp = (VARDEF *)emalloc(sizeof(VARDEF));
    vp->lib = liblookup(name);
    if (vp->lib == NULL)                /* if name not in library */
        name = qualname(name, 0);       /* use fully qualified version */
    hv = hash(name);
    vp->name = savestr(name);
    vp->nlinks = 1;
    vp->def = NULL;
    vp->next = hashtbl[hv];
    hashtbl[hv] = vp;
    return(vp);
}


void
libupdate(                      /* update library links */
        char  *fn
)
{
    int  i;
    VARDEF  *vp;
                                        /* if fn is NULL then relink all */
    for (i = 0; i < NHASH; i++)
        for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
            if ((vp->lib != NULL) | (fn == NULL) || !strcmp(fn, vp->name))
                vp->lib = liblookup(vp->name);
}


void
varfree(                                /* release link to variable */
        VARDEF   *ln
)
{
    VARDEF  *vp;
    int  hv;

    if (--ln->nlinks > 0)
        return;                         /* still active */

    hv = hash(ln->name);
    vp = hashtbl[hv];
    if (vp == ln)
        hashtbl[hv] = vp->next;
    else {
        while (vp->next != ln)          /* must be in list */
                vp = vp->next;
        vp->next = ln->next;
    }
    freestr(ln->name);
    efree(ln);
}


EPNODE *
dfirst(void)                    /* return pointer to first definition */
{
    htndx = 0;
    htpos = NULL;
    ochpos = outchan;
    return(dnext());
}


EPNODE *
dnext(void)                             /* return pointer to next definition */
{
    EPNODE  *ep;
    char  *nm;

    while (htndx < NHASH) {
        if (htpos == NULL)
                htpos = hashtbl[htndx++];
        while (htpos != NULL) {
            ep = htpos->def;
            nm = htpos->name;
            htpos = htpos->next;
            if (ep != NULL && incontext(nm))
                return(ep);
        }
    }
    if ((ep = ochpos) != NULL)
        ochpos = ep->sibling;
    return(ep);
}


EPNODE *
dpop(                   /* pop a definition */
        char  *name
)
{
    VARDEF  *vp;
    EPNODE  *dp;
    
    if ((vp = varlookup(name)) == NULL || vp->def == NULL)
        return(NULL);
    dp = vp->def;
    vp->def = dp->sibling;
    varfree(vp);
    return(dp);
}


void
dpush(                  /* push on a definition */
        char  *nm,
        EPNODE   *ep
)
{
    VARDEF  *vp;

    vp = varinsert(nm);
    ep->sibling = vp->def;
    vp->def = ep;
}


void
addchan(                        /* add an output channel assignment */
        EPNODE  *sp
)
{
    int  ch = sp->v.kid->v.chan;
    EPNODE  *ep, *epl;

    for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling)
        if (ep->v.kid->v.chan >= ch) {
            if (epl != NULL)
                epl->sibling = sp;
            else
                outchan = sp;
            if (ep->v.kid->v.chan > ch)
                sp->sibling = ep;
            else {
                sp->sibling = ep->sibling;
                epfree(ep);
            }
            return;
        }
    if (epl != NULL)
        epl->sibling = sp;
    else
        outchan = sp;
    sp->sibling = NULL;

}


void
getstatement(void)                      /* get next statement */
{
    EPNODE  *ep;
    char  *qname;
    VARDEF  *vdef;

    if (nextc == ';') {         /* empty statement */
        scan();
        return;
    }
    if (esupport&E_OUTCHAN &&
                nextc == '$') {         /* channel assignment */
        ep = getchan();
        addchan(ep);
    } else {                            /* ordinary definition */
        ep = getdefn();
        qname = qualname(dfn_name(ep), 0);
        if (esupport&E_REDEFW && (vdef = varlookup(qname)) != NULL) {
            if (vdef->def != NULL && epcmp(ep, vdef->def)) {
                wputs(qname);
                if (vdef->def->type == ':')
                    wputs(": redefined constant expression\n");
                else
                    wputs(": redefined\n");
            } else if (ep->v.kid->type == FUNC && vdef->lib != NULL) {
                wputs(qname);
                wputs(": definition hides library function\n");
            }
        }
        if (ep->type == ':')
            dremove(qname);
        else
            dclear(qname);
        dpush(qname, ep);
    }
    if (nextc != EOF) {
        if (nextc != ';')
            syntax("';' expected");
        scan();
    }
}


EPNODE *
getdefn(void)
        /* A -> SYM = E1 */
        /*      SYM : E1 */
        /*      FUNC(SYM,..) = E1 */
        /*      FUNC(SYM,..) : E1 */
{
    EPNODE  *ep1, *ep2;

    if (!isalpha(nextc) & (nextc != CNTXMARK))
        syntax("illegal variable name");

    ep1 = newnode();
    ep1->type = SYM;
    ep1->v.name = savestr(getname());

    if (esupport&E_FUNCTION && nextc == '(') {
        ep2 = newnode();
        ep2->type = FUNC;
        addekid(ep2, ep1);
        ep1 = ep2;
        do {
            scan();
            if (!isalpha(nextc))
                syntax("illegal parameter name");
            ep2 = newnode();
            ep2->type = SYM;
            ep2->v.name = savestr(getname());
            if (strchr(ep2->v.name, CNTXMARK) != NULL)
                syntax("illegal parameter name");
            addekid(ep1, ep2);
        } while (nextc == ',');
        if (nextc != ')')
            syntax("')' expected");
        scan();
        curfunc = ep1;
    }

    if ((nextc != '=') & (nextc != ':'))
        syntax("'=' or ':' expected");

    ep2 = newnode();
    ep2->type = nextc;
    scan();
    addekid(ep2, ep1);
    addekid(ep2, getE1());

    if (ep1->type == SYM && ep1->sibling->type != NUM) {
        ep1 = newnode();
        ep1->type = CLKT;
        ep1->v.tick = 0;
        addekid(ep2, ep1);
        ep1 = newnode();
        ep1->type = NUM;
        addekid(ep2, ep1);
    }
    curfunc = NULL;

    return(ep2);
}


EPNODE *
getchan(void)                   /* A -> $N = E1 */
{
    EPNODE  *ep1, *ep2;

    if (nextc != '$')
        syntax("missing '$'");
    scan();

    ep1 = newnode();
    ep1->type = CHAN;
    ep1->v.chan = getinum();

    if (nextc != '=')
        syntax("'=' expected");
    scan();

    ep2 = newnode();
    ep2->type = '=';
    addekid(ep2, ep1);
    addekid(ep2, getE1());

    return(ep2);
}


/*
 *  The following routines are for internal use only:
 */


static double                   /* evaluate a variable */
dvalue(char *name, EPNODE *d)
{
    EPNODE  *ep1, *ep2;
    
    if (d == NULL || d->v.kid->type != SYM) {
        eputs(name);
        eputs(": undefined variable\n");
        quit(1);
    }
    ep1 = d->v.kid->sibling;                    /* get expression */
    if (ep1->type == NUM)
        return(ep1->v.num);                     /* return if number */
    if (esupport&E_RCONST && d->type == ':') {
        wputs(name);
        wputs(": assigned non-constant value\n");
    }
    ep2 = ep1->sibling;                         /* check time */
    if (eclock >= MAXCLOCK)
        eclock = 1;                             /* wrap clock counter */
    if (ep2->v.tick < MAXCLOCK &&
                (ep2->v.tick == 0) | (ep2->v.tick != eclock)) {
        ep2->v.tick = d->type == ':' ? MAXCLOCK : eclock;
        ep2 = ep2->sibling;
        ep2->v.num = evalue(ep1);               /* needs new value */
    } else
        ep2 = ep2->sibling;                     /* else reuse old value */

    return(ep2->v.num);
}
Revision:	2.36
Committed:	Tue Sep 26 18:33:14 2023 UTC (7 months, 3 weeks ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.35:	+5 -9 lines
Log Message:	style: minor code clean-ups
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.36	static const char RCSid[] = "$Id: caldefn.c,v 2.35 2023/09/26 00:14:02 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* Store variable definitions.
6			*
7			* 7/1/85 Greg Ward
8			*
9			* 11/11/85 Added conditional compiles (OUTCHAN) for control output.
10			*
11			* 4/2/86 Added conditional compiles for function definitions (FUNCTION).
12			*
13			* 1/15/88 Added clock for caching of variable values.
14			*
15			* 11/16/88 Added VARDEF structure for hard linking.
16	greg	1.2	*
17			* 5/31/90 Added conditional compile (REDEFW) for redefinition warning.
18	greg	1.8	*
19	greg	1.10	* 4/23/91 Added ':' assignment for constant expressions
20	greg	1.13	*
21			* 8/7/91 Added optional context path to append to variable names
22	greg	2.12	*
23			* 5/17/2001 Fixed clock counter wrapping behavior
24			*
25			* 2/19/03 Eliminated conditional compiles in favor of esupport extern.
26			*/
27
28	greg	2.13	#include "copyright.h"
29	greg	1.1
30			#include <ctype.h>
31
32	schorsch	2.18	#include "rterror.h"
33	schorsch	2.22	#include "rtio.h"
34	schorsch	2.21	#include "rtmisc.h"
35	greg	1.1	#include "calcomp.h"
36
37	greg	2.4	#ifndef NHASH
38			#define NHASH 521 /* hash size (a prime!) */
39	greg	1.1	#endif
40
41	greg	2.5	#define hash(s) (shash(s)%NHASH)
42
43	greg	2.4	#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE))
44	greg	1.1
45	schorsch	2.18	static double dvalue(char name, EPNODE d);
46	greg	1.1
47	greg	2.12	#define MAXCLOCK (1L<<31) /* clock wrap value */
48	greg	1.1
49	greg	2.8	unsigned long eclock = 0; /* value storage timer */
50	greg	1.1
51	greg	2.11	#define MAXCNTX 1023 /* maximum context length */
52	greg	1.13
53	greg	2.11	static char context[MAXCNTX+1]; /* current context path */
54
55	greg	1.1	static VARDEF hashtbl[NHASH]; / definition list */
56			static int htndx; /* index for */
57			static VARDEF htpos; / ...dfirst() and */
58			static EPNODE ochpos; / ...dnext */
59			static EPNODE *outchan;
60
61	greg	2.10	EPNODE *curfunc = NULL;
62	greg	1.1
63
64	greg	2.12	void
65	schorsch	2.16	fcompile( /* get definitions from a file */
66			char *fname
67			)
68	greg	1.1	{
69			FILE *fp;
70
71			if (fname == NULL)
72			fp = stdin;
73			else if ((fp = fopen(fname, "r")) == NULL) {
74			eputs(fname);
75			eputs(": cannot open\n");
76			quit(1);
77			}
78	greg	2.34	#ifdef getc_unlocked /* avoid stupid semaphores */
79			flockfile(fp);
80			#endif
81			initfile(fp, fname, 0);
82	greg	1.1	while (nextc != EOF)
83	greg	1.13	getstatement();
84	greg	1.1	if (fname != NULL)
85			fclose(fp);
86	greg	2.34	#ifdef getc_unlocked
87			else
88			funlockfile(fp);
89			#endif
90	greg	1.1	}
91
92
93	greg	2.12	void
94	schorsch	2.16	scompile( /* get definitions from a string */
95			char *str,
96			char *fn,
97			int ln
98			)
99	greg	1.1	{
100	greg	1.4	initstr(str, fn, ln);
101	greg	1.1	while (nextc != EOF)
102	greg	1.13	getstatement();
103	greg	1.1	}
104
105
106			double
107	schorsch	2.16	varvalue( /* return a variable's value */
108			char *vname
109			)
110	greg	1.1	{
111			return(dvalue(vname, dlookup(vname)));
112			}
113
114
115			double
116	schorsch	2.16	evariable( /* evaluate a variable */
117			EPNODE *ep
118			)
119	greg	1.1	{
120	greg	2.25	VARDEF *dp = ep->v.ln;
121	greg	1.1
122			return(dvalue(dp->name, dp->def));
123			}
124
125
126	greg	2.12	void
127	schorsch	2.16	varset( /* set a variable's value */
128			char *vname,
129			int assign,
130			double val
131			)
132	greg	1.1	{
133	greg	1.13	char *qname;
134	greg	2.25	EPNODE ep1, ep2;
135	greg	1.13	/* get qualified name */
136			qname = qualname(vname, 0);
137	greg	1.1	/* check for quick set */
138	greg	2.25	if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM &&
139			(ep1->type == ':') <= (assign == ':')) {
140	greg	1.1	ep2 = ep1->v.kid->sibling;
141			if (ep2->type == NUM) {
142			ep2->v.num = val;
143	greg	1.8	ep1->type = assign;
144	greg	1.1	return;
145			}
146			}
147	greg	2.26	if (ep1 != NULL && esupport&E_REDEFW) {
148			wputs(qname);
149			if (ep1->type == ':')
150			wputs(": reset constant expression\n");
151			else
152			wputs(": reset expression\n");
153			}
154	greg	1.1	/* hand build definition */
155			ep1 = newnode();
156	greg	1.8	ep1->type = assign;
157	greg	1.1	ep2 = newnode();
158			ep2->type = SYM;
159			ep2->v.name = savestr(vname);
160			addekid(ep1, ep2);
161			ep2 = newnode();
162			ep2->type = NUM;
163			ep2->v.num = val;
164			addekid(ep1, ep2);
165	greg	2.25	if (assign == ':')
166			dremove(qname);
167			else
168			dclear(qname);
169	greg	1.13	dpush(qname, ep1);
170	greg	1.1	}
171
172
173	greg	2.12	void
174	schorsch	2.16	dclear( /* delete variable definitions of name */
175			char *name
176			)
177	greg	1.1	{
178	greg	2.25	EPNODE *ep;
179	greg	1.1
180	greg	1.8	while ((ep = dpop(name)) != NULL) {
181			if (ep->type == ':') {
182	greg	1.13	dpush(name, ep); /* don't clear constants */
183	greg	1.8	return;
184			}
185			epfree(ep);
186			}
187			}
188
189
190	greg	2.12	void
191	schorsch	2.16	dremove( /* delete all definitions of name */
192			char *name
193			)
194	greg	1.8	{
195	greg	2.25	EPNODE *ep;
196	greg	1.8
197	greg	1.1	while ((ep = dpop(name)) != NULL)
198			epfree(ep);
199			}
200
201
202	greg	2.12	int
203	greg	2.30	vardefined( /* return '=' or ':' if variable/constant defined */
204	schorsch	2.16	char *name
205			)
206	greg	1.1	{
207	greg	2.31	EPNODE *dp = dlookup(name);
208	greg	1.1
209	greg	2.31	if (dp == NULL \|\| dp->v.kid->type != SYM)
210	greg	2.30	return(0);
211	greg	2.31
212	greg	2.30	return(dp->type);
213	greg	1.1	}
214
215
216	greg	1.13	char *
217	greg	2.32	calcontext( /* set a new context path */
218	greg	2.25	char *ctx
219	schorsch	2.16	)
220	greg	1.13	{
221	greg	2.25	char *cpp;
222	greg	1.13
223			if (ctx == NULL)
224			return(context); /* just asking */
225	greg	2.6	while (*ctx == CNTXMARK)
226			ctx++; /* skip past marks */
227	greg	1.13	if (!*ctx) {
228	greg	2.6	context[0] = '\0'; /* empty means clear context */
229	greg	1.13	return(context);
230			}
231	greg	2.6	cpp = context; /* start context with mark */
232			*cpp++ = CNTXMARK;
233			do { /* carefully copy new context */
234	greg	2.11	if (cpp >= context+MAXCNTX)
235	greg	1.18	break; /* just copy what we can */
236	greg	1.13	if (isid(*ctx))
237			cpp++ = ctx++;
238			else {
239			*cpp++ = '_'; ctx++;
240			}
241			} while (*ctx);
242	greg	2.6	while (cpp[-1] == CNTXMARK) /* cannot end in context mark */
243			cpp--;
244	greg	1.13	*cpp = '\0';
245	greg	2.6	return(context);
246			}
247
248
249			char *
250	schorsch	2.16	pushcontext( /* push on another context */
251			char *ctx
252			)
253	greg	2.6	{
254	greg	2.11	char oldcontext[MAXCNTX+1];
255	greg	2.25	int n;
256	greg	2.6
257			strcpy(oldcontext, context); /* save old context */
258	greg	2.32	calcontext(ctx); /* set new context */
259	greg	2.6	n = strlen(context); /* tack on old */
260	greg	2.11	if (n+strlen(oldcontext) > MAXCNTX) {
261			strncpy(context+n, oldcontext, MAXCNTX-n);
262			context[MAXCNTX] = '\0';
263	greg	2.6	} else
264			strcpy(context+n, oldcontext);
265			return(context);
266			}
267
268
269			char *
270	schorsch	2.16	popcontext(void) /* pop off top context */
271	greg	2.6	{
272	greg	2.25	char cp1, cp2;
273	greg	2.6
274			if (!context[0]) /* nothing left to pop */
275			return(context);
276			cp2 = context; /* find mark */
277			while (++cp2 && cp2 != CNTXMARK)
278			;
279			cp1 = context; /* copy tail to front */
280	schorsch	2.20	while ( (cp1++ = cp2++) )
281	greg	2.6	;
282	greg	1.13	return(context);
283			}
284
285
286			char *
287	schorsch	2.16	qualname( /* get qualified name */
288	greg	2.25	char *nam,
289	schorsch	2.16	int lvl
290			)
291	greg	1.13	{
292	schorsch	2.17	static char nambuf[RMAXWORD+1];
293	greg	2.25	char cp = nambuf, cpp;
294	greg	1.17	/* check for explicit local */
295	greg	2.36	if (*nam == CNTXMARK) {
296	greg	1.17	if (lvl > 0) /* only action is to refuse search */
297			return(NULL);
298	greg	2.36	nam++;
299			} else if (nam == nambuf) /* check for repeat call */
300	greg	1.17	return(lvl > 0 ? NULL : nam);
301	greg	1.13	/* copy name to static buffer */
302			while (*nam) {
303	schorsch	2.17	if (cp >= nambuf+RMAXWORD)
304	greg	1.13	goto toolong;
305	greg	1.17	cp++ = nam++;
306	greg	1.13	}
307	greg	1.17	/* check for explicit global */
308			if (cp > nambuf && cp[-1] == CNTXMARK) {
309	greg	1.13	if (lvl > 0)
310	greg	1.17	return(NULL);
311			*--cp = '\0';
312			return(nambuf); /* already qualified */
313			}
314			cpp = context; /* else skip the requested levels */
315			while (lvl-- > 0) {
316			if (!*cpp)
317			return(NULL); /* return NULL if past global level */
318			while (++cpp && cpp != CNTXMARK)
319			;
320			}
321	greg	1.13	while (cpp) { / copy context to static buffer */
322	schorsch	2.17	if (cp >= nambuf+RMAXWORD)
323	greg	1.13	goto toolong;
324			cp++ = cpp++;
325			}
326	greg	1.18	toolong:
327	greg	1.13	*cp = '\0';
328			return(nambuf); /* return qualified name */
329			}
330
331
332	greg	2.12	int
333	schorsch	2.16	incontext( /* is qualified name in current context? */
334	greg	2.25	char *qn
335	schorsch	2.16	)
336	greg	1.14	{
337	greg	2.9	if (!context[0]) /* global context accepts all */
338			return(1);
339	greg	1.14	while (qn && qn != CNTXMARK) /* find context mark */
340	greg	1.19	qn++;
341	greg	1.14	return(!strcmp(qn, context));
342			}
343
344
345	greg	2.12	void
346	schorsch	2.16	chanout( /* set output channels */
347			void (*cs)(int n, double v)
348			)
349	greg	1.1	{
350	greg	2.25	EPNODE *ep;
351	greg	1.1
352			for (ep = outchan; ep != NULL; ep = ep->sibling)
353	greg	1.6	(*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling));
354	greg	1.1
355			}
356
357
358	greg	2.12	void
359	schorsch	2.16	dcleanup( /* clear definitions (0->vars,1->output,2->consts) */
360			int lvl
361			)
362	greg	1.1	{
363	greg	2.25	int i;
364			VARDEF *vp;
365			EPNODE *ep;
366	greg	1.14	/* if context is global, clear all */
367	greg	1.1	for (i = 0; i < NHASH; i++)
368			for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
369	schorsch	2.19	if (incontext(vp->name)) {
370	greg	1.14	if (lvl >= 2)
371			dremove(vp->name);
372			else
373			dclear(vp->name);
374	schorsch	2.19	}
375	greg	2.35	if (lvl >= 1)
376			while (outchan != NULL) {
377			ep = outchan;
378			outchan = ep->sibling;
379			ep->sibling = NULL;
380	greg	1.9	epfree(ep);
381	greg	2.35	}
382	greg	1.1	}
383
384
385			EPNODE *
386	schorsch	2.16	dlookup( /* look up a definition */
387			char *name
388			)
389	greg	1.1	{
390	greg	2.25	VARDEF *vp;
391	greg	1.1
392			if ((vp = varlookup(name)) == NULL)
393	greg	2.4	return(NULL);
394	greg	1.1	return(vp->def);
395			}
396
397
398			VARDEF *
399	schorsch	2.16	varlookup( /* look up a variable */
400			char *name
401			)
402	greg	1.1	{
403	greg	2.4	int lvl = 0;
404	greg	2.25	char *qname;
405			VARDEF *vp;
406	greg	2.4	/* find most qualified match */
407	greg	1.13	while ((qname = qualname(name, lvl++)) != NULL)
408			for (vp = hashtbl[hash(qname)]; vp != NULL; vp = vp->next)
409			if (!strcmp(vp->name, qname))
410			return(vp);
411	greg	1.1	return(NULL);
412			}
413
414
415			VARDEF *
416	schorsch	2.16	varinsert( /* get a link to a variable */
417			char *name
418			)
419	greg	1.1	{
420	greg	2.25	VARDEF *vp;
421	greg	2.4	int hv;
422	greg	1.1
423	greg	1.13	if ((vp = varlookup(name)) != NULL) {
424			vp->nlinks++;
425			return(vp);
426			}
427	greg	2.3	vp = (VARDEF *)emalloc(sizeof(VARDEF));
428			vp->lib = liblookup(name);
429			if (vp->lib == NULL) /* if name not in library */
430	greg	1.16	name = qualname(name, 0); /* use fully qualified version */
431	greg	1.1	hv = hash(name);
432			vp->name = savestr(name);
433			vp->nlinks = 1;
434			vp->def = NULL;
435			vp->next = hashtbl[hv];
436			hashtbl[hv] = vp;
437			return(vp);
438			}
439	greg	2.2
440
441	greg	2.12	void
442	schorsch	2.16	libupdate( /* update library links */
443			char *fn
444			)
445	greg	2.2	{
446	greg	2.25	int i;
447			VARDEF *vp;
448	greg	2.2	/* if fn is NULL then relink all */
449			for (i = 0; i < NHASH; i++)
450			for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
451	greg	2.33	if ((vp->lib != NULL) \| (fn == NULL) \|\| !strcmp(fn, vp->name))
452	greg	2.2	vp->lib = liblookup(vp->name);
453			}
454	greg	1.1
455
456	greg	2.12	void
457	schorsch	2.16	varfree( /* release link to variable */
458	greg	2.25	VARDEF *ln
459	schorsch	2.16	)
460	greg	1.1	{
461	greg	2.25	VARDEF *vp;
462	greg	2.4	int hv;
463	greg	1.1
464			if (--ln->nlinks > 0)
465	greg	2.4	return; /* still active */
466	greg	1.1
467			hv = hash(ln->name);
468			vp = hashtbl[hv];
469			if (vp == ln)
470	greg	2.4	hashtbl[hv] = vp->next;
471	greg	1.1	else {
472	greg	2.4	while (vp->next != ln) /* must be in list */
473			vp = vp->next;
474			vp->next = ln->next;
475	greg	1.1	}
476			freestr(ln->name);
477	greg	2.35	efree(ln);
478	greg	1.1	}
479
480
481			EPNODE *
482	schorsch	2.16	dfirst(void) /* return pointer to first definition */
483	greg	1.1	{
484			htndx = 0;
485			htpos = NULL;
486			ochpos = outchan;
487			return(dnext());
488			}
489
490
491			EPNODE *
492	schorsch	2.16	dnext(void) /* return pointer to next definition */
493	greg	1.1	{
494	greg	2.25	EPNODE *ep;
495			char *nm;
496	greg	1.1
497			while (htndx < NHASH) {
498	greg	2.4	if (htpos == NULL)
499			htpos = hashtbl[htndx++];
500			while (htpos != NULL) {
501			ep = htpos->def;
502	greg	1.19	nm = htpos->name;
503	greg	2.4	htpos = htpos->next;
504			if (ep != NULL && incontext(nm))
505			return(ep);
506			}
507	greg	1.1	}
508			if ((ep = ochpos) != NULL)
509	greg	2.4	ochpos = ep->sibling;
510	greg	1.1	return(ep);
511			}
512
513
514			EPNODE *
515	schorsch	2.16	dpop( /* pop a definition */
516			char *name
517			)
518	greg	1.1	{
519	greg	2.25	VARDEF *vp;
520			EPNODE *dp;
521	greg	1.1
522			if ((vp = varlookup(name)) == NULL \|\| vp->def == NULL)
523	greg	2.4	return(NULL);
524	greg	1.1	dp = vp->def;
525			vp->def = dp->sibling;
526			varfree(vp);
527			return(dp);
528			}
529
530
531	greg	2.12	void
532	schorsch	2.16	dpush( /* push on a definition */
533			char *nm,
534	greg	2.25	EPNODE *ep
535	schorsch	2.16	)
536	greg	1.1	{
537	greg	2.25	VARDEF *vp;
538	greg	1.1
539	greg	1.13	vp = varinsert(nm);
540	greg	1.1	ep->sibling = vp->def;
541			vp->def = ep;
542			}
543
544
545	greg	2.12	void
546	schorsch	2.16	addchan( /* add an output channel assignment */
547			EPNODE *sp
548			)
549	greg	1.1	{
550	greg	2.4	int ch = sp->v.kid->v.chan;
551	greg	2.25	EPNODE ep, epl;
552	greg	1.1
553			for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling)
554			if (ep->v.kid->v.chan >= ch) {
555			if (epl != NULL)
556			epl->sibling = sp;
557			else
558			outchan = sp;
559			if (ep->v.kid->v.chan > ch)
560			sp->sibling = ep;
561			else {
562			sp->sibling = ep->sibling;
563			epfree(ep);
564			}
565			return;
566			}
567			if (epl != NULL)
568			epl->sibling = sp;
569			else
570			outchan = sp;
571			sp->sibling = NULL;
572
573			}
574
575
576	greg	2.12	void
577	schorsch	2.16	getstatement(void) /* get next statement */
578	greg	1.1	{
579	greg	2.25	EPNODE *ep;
580	greg	1.13	char *qname;
581	greg	2.25	VARDEF *vdef;
582	greg	1.1
583			if (nextc == ';') { /* empty statement */
584			scan();
585			return;
586			}
587	greg	2.12	if (esupport&E_OUTCHAN &&
588			nextc == '$') { /* channel assignment */
589	greg	1.1	ep = getchan();
590			addchan(ep);
591	greg	2.12	} else { /* ordinary definition */
592	greg	1.1	ep = getdefn();
593	greg	2.36	qname = qualname(dfn_name(ep), 0);
594	schorsch	2.19	if (esupport&E_REDEFW && (vdef = varlookup(qname)) != NULL) {
595	greg	2.7	if (vdef->def != NULL && epcmp(ep, vdef->def)) {
596	greg	1.16	wputs(qname);
597			if (vdef->def->type == ':')
598			wputs(": redefined constant expression\n");
599			else
600			wputs(": redefined\n");
601	greg	2.12	} else if (ep->v.kid->type == FUNC && vdef->lib != NULL) {
602	greg	1.16	wputs(qname);
603			wputs(": definition hides library function\n");
604			}
605	schorsch	2.19	}
606	greg	1.10	if (ep->type == ':')
607	greg	1.13	dremove(qname);
608	greg	1.10	else
609	greg	1.13	dclear(qname);
610			dpush(qname, ep);
611	greg	1.1	}
612			if (nextc != EOF) {
613			if (nextc != ';')
614			syntax("';' expected");
615			scan();
616			}
617			}
618
619
620			EPNODE *
621	schorsch	2.16	getdefn(void)
622			/* A -> SYM = E1 */
623			/* SYM : E1 */
624			/* FUNC(SYM,..) = E1 */
625			/* FUNC(SYM,..) : E1 */
626	greg	1.1	{
627	greg	2.25	EPNODE ep1, ep2;
628	greg	1.1
629	greg	2.33	if (!isalpha(nextc) & (nextc != CNTXMARK))
630	greg	1.1	syntax("illegal variable name");
631
632			ep1 = newnode();
633			ep1->type = SYM;
634			ep1->v.name = savestr(getname());
635
636	greg	2.12	if (esupport&E_FUNCTION && nextc == '(') {
637	greg	1.1	ep2 = newnode();
638			ep2->type = FUNC;
639			addekid(ep2, ep1);
640			ep1 = ep2;
641			do {
642			scan();
643			if (!isalpha(nextc))
644	greg	2.24	syntax("illegal parameter name");
645	greg	1.1	ep2 = newnode();
646			ep2->type = SYM;
647			ep2->v.name = savestr(getname());
648	greg	2.29	if (strchr(ep2->v.name, CNTXMARK) != NULL)
649			syntax("illegal parameter name");
650	greg	1.1	addekid(ep1, ep2);
651			} while (nextc == ',');
652			if (nextc != ')')
653			syntax("')' expected");
654			scan();
655			curfunc = ep1;
656	greg	2.10	}
657	greg	1.1
658	greg	2.33	if ((nextc != '=') & (nextc != ':'))
659	greg	1.8	syntax("'=' or ':' expected");
660	greg	1.1
661			ep2 = newnode();
662	greg	1.8	ep2->type = nextc;
663			scan();
664	greg	1.1	addekid(ep2, ep1);
665			addekid(ep2, getE1());
666
667	greg	2.12	if (ep1->type == SYM && ep1->sibling->type != NUM) {
668	greg	1.1	ep1 = newnode();
669	greg	2.23	ep1->type = CLKT;
670	greg	2.8	ep1->v.tick = 0;
671	greg	1.1	addekid(ep2, ep1);
672			ep1 = newnode();
673			ep1->type = NUM;
674			addekid(ep2, ep1);
675			}
676	greg	2.10	curfunc = NULL;
677	greg	1.1
678			return(ep2);
679			}
680
681
682			EPNODE *
683	schorsch	2.16	getchan(void) /* A -> $N = E1 */
684	greg	1.1	{
685	greg	2.25	EPNODE ep1, ep2;
686	greg	1.1
687			if (nextc != '$')
688			syntax("missing '$'");
689			scan();
690
691			ep1 = newnode();
692			ep1->type = CHAN;
693			ep1->v.chan = getinum();
694
695			if (nextc != '=')
696			syntax("'=' expected");
697			scan();
698
699			ep2 = newnode();
700			ep2->type = '=';
701			addekid(ep2, ep1);
702			addekid(ep2, getE1());
703
704			return(ep2);
705			}
706
707
708
709			/*
710			* The following routines are for internal use only:
711			*/
712
713
714	schorsch	2.18	static double /* evaluate a variable */
715	greg	2.28	dvalue(char name, EPNODE d)
716	greg	1.1	{
717	greg	2.25	EPNODE ep1, ep2;
718	greg	1.1
719			if (d == NULL \|\| d->v.kid->type != SYM) {
720			eputs(name);
721			eputs(": undefined variable\n");
722			quit(1);
723			}
724			ep1 = d->v.kid->sibling; /* get expression */
725	greg	1.5	if (ep1->type == NUM)
726			return(ep1->v.num); /* return if number */
727	greg	2.28	if (esupport&E_RCONST && d->type == ':') {
728			wputs(name);
729			wputs(": assigned non-constant value\n");
730			}
731	greg	1.1	ep2 = ep1->sibling; /* check time */
732	greg	2.12	if (eclock >= MAXCLOCK)
733			eclock = 1; /* wrap clock counter */
734			if (ep2->v.tick < MAXCLOCK &&
735	schorsch	2.20	(ep2->v.tick == 0) \| (ep2->v.tick != eclock)) {
736	greg	2.12	ep2->v.tick = d->type == ':' ? MAXCLOCK : eclock;
737	greg	1.1	ep2 = ep2->sibling;
738	greg	1.5	ep2->v.num = evalue(ep1); /* needs new value */
739	greg	1.1	} else
740	greg	1.5	ep2 = ep2->sibling; /* else reuse old value */
741	greg	1.1
742			return(ep2->v.num);
743			}