src/common/caldefn.c

#ifndef lint
static const char       RCSid[] = "$Id: caldefn.c,v 2.33 2022/04/08 23:32:25 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;
#define  dname(ep)      ((ep)->v.kid->type == SYM ? \
                        (ep)->v.kid->v.name : \
                        (ep)->v.kid->v.kid->v.name)


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);
        else
            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) {
        for (ep = outchan; ep != NULL; ep = ep->sibling)
            epfree(ep);
        outchan = NULL;
    }
}


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((char *)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(dname(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:	2.34
Committed:	Tue Feb 7 20:28:16 2023 UTC (15 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.33:	+9 -2 lines
Log Message:	perf: added calls to flockfile()/funlockfile() for more efficient reading
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.34	static const char RCSid[] = "$Id: caldefn.c,v 2.33 2022/04/08 23:32:25 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	2.4	#define dname(ep) ((ep)->v.kid->type == SYM ? \
63	greg	1.1	(ep)->v.kid->v.name : \
64			(ep)->v.kid->v.kid->v.name)
65
66
67	greg	2.12	void
68	schorsch	2.16	fcompile( /* get definitions from a file */
69			char *fname
70			)
71	greg	1.1	{
72			FILE *fp;
73
74			if (fname == NULL)
75			fp = stdin;
76			else if ((fp = fopen(fname, "r")) == NULL) {
77			eputs(fname);
78			eputs(": cannot open\n");
79			quit(1);
80			}
81	greg	2.34	#ifdef getc_unlocked /* avoid stupid semaphores */
82			flockfile(fp);
83			#endif
84			initfile(fp, fname, 0);
85	greg	1.1	while (nextc != EOF)
86	greg	1.13	getstatement();
87	greg	1.1	if (fname != NULL)
88			fclose(fp);
89	greg	2.34	#ifdef getc_unlocked
90			else
91			funlockfile(fp);
92			#endif
93	greg	1.1	}
94
95
96	greg	2.12	void
97	schorsch	2.16	scompile( /* get definitions from a string */
98			char *str,
99			char *fn,
100			int ln
101			)
102	greg	1.1	{
103	greg	1.4	initstr(str, fn, ln);
104	greg	1.1	while (nextc != EOF)
105	greg	1.13	getstatement();
106	greg	1.1	}
107
108
109			double
110	schorsch	2.16	varvalue( /* return a variable's value */
111			char *vname
112			)
113	greg	1.1	{
114			return(dvalue(vname, dlookup(vname)));
115			}
116
117
118			double
119	schorsch	2.16	evariable( /* evaluate a variable */
120			EPNODE *ep
121			)
122	greg	1.1	{
123	greg	2.25	VARDEF *dp = ep->v.ln;
124	greg	1.1
125			return(dvalue(dp->name, dp->def));
126			}
127
128
129	greg	2.12	void
130	schorsch	2.16	varset( /* set a variable's value */
131			char *vname,
132			int assign,
133			double val
134			)
135	greg	1.1	{
136	greg	1.13	char *qname;
137	greg	2.25	EPNODE ep1, ep2;
138	greg	1.13	/* get qualified name */
139			qname = qualname(vname, 0);
140	greg	1.1	/* check for quick set */
141	greg	2.25	if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM &&
142			(ep1->type == ':') <= (assign == ':')) {
143	greg	1.1	ep2 = ep1->v.kid->sibling;
144			if (ep2->type == NUM) {
145			ep2->v.num = val;
146	greg	1.8	ep1->type = assign;
147	greg	1.1	return;
148			}
149			}
150	greg	2.26	if (ep1 != NULL && esupport&E_REDEFW) {
151			wputs(qname);
152			if (ep1->type == ':')
153			wputs(": reset constant expression\n");
154			else
155			wputs(": reset expression\n");
156			}
157	greg	1.1	/* hand build definition */
158			ep1 = newnode();
159	greg	1.8	ep1->type = assign;
160	greg	1.1	ep2 = newnode();
161			ep2->type = SYM;
162			ep2->v.name = savestr(vname);
163			addekid(ep1, ep2);
164			ep2 = newnode();
165			ep2->type = NUM;
166			ep2->v.num = val;
167			addekid(ep1, ep2);
168	greg	2.25	if (assign == ':')
169			dremove(qname);
170			else
171			dclear(qname);
172	greg	1.13	dpush(qname, ep1);
173	greg	1.1	}
174
175
176	greg	2.12	void
177	schorsch	2.16	dclear( /* delete variable definitions of name */
178			char *name
179			)
180	greg	1.1	{
181	greg	2.25	EPNODE *ep;
182	greg	1.1
183	greg	1.8	while ((ep = dpop(name)) != NULL) {
184			if (ep->type == ':') {
185	greg	1.13	dpush(name, ep); /* don't clear constants */
186	greg	1.8	return;
187			}
188			epfree(ep);
189			}
190			}
191
192
193	greg	2.12	void
194	schorsch	2.16	dremove( /* delete all definitions of name */
195			char *name
196			)
197	greg	1.8	{
198	greg	2.25	EPNODE *ep;
199	greg	1.8
200	greg	1.1	while ((ep = dpop(name)) != NULL)
201			epfree(ep);
202			}
203
204
205	greg	2.12	int
206	greg	2.30	vardefined( /* return '=' or ':' if variable/constant defined */
207	schorsch	2.16	char *name
208			)
209	greg	1.1	{
210	greg	2.31	EPNODE *dp = dlookup(name);
211	greg	1.1
212	greg	2.31	if (dp == NULL \|\| dp->v.kid->type != SYM)
213	greg	2.30	return(0);
214	greg	2.31
215	greg	2.30	return(dp->type);
216	greg	1.1	}
217
218
219	greg	1.13	char *
220	greg	2.32	calcontext( /* set a new context path */
221	greg	2.25	char *ctx
222	schorsch	2.16	)
223	greg	1.13	{
224	greg	2.25	char *cpp;
225	greg	1.13
226			if (ctx == NULL)
227			return(context); /* just asking */
228	greg	2.6	while (*ctx == CNTXMARK)
229			ctx++; /* skip past marks */
230	greg	1.13	if (!*ctx) {
231	greg	2.6	context[0] = '\0'; /* empty means clear context */
232	greg	1.13	return(context);
233			}
234	greg	2.6	cpp = context; /* start context with mark */
235			*cpp++ = CNTXMARK;
236			do { /* carefully copy new context */
237	greg	2.11	if (cpp >= context+MAXCNTX)
238	greg	1.18	break; /* just copy what we can */
239	greg	1.13	if (isid(*ctx))
240			cpp++ = ctx++;
241			else {
242			*cpp++ = '_'; ctx++;
243			}
244			} while (*ctx);
245	greg	2.6	while (cpp[-1] == CNTXMARK) /* cannot end in context mark */
246			cpp--;
247	greg	1.13	*cpp = '\0';
248	greg	2.6	return(context);
249			}
250
251
252			char *
253	schorsch	2.16	pushcontext( /* push on another context */
254			char *ctx
255			)
256	greg	2.6	{
257	greg	2.11	char oldcontext[MAXCNTX+1];
258	greg	2.25	int n;
259	greg	2.6
260			strcpy(oldcontext, context); /* save old context */
261	greg	2.32	calcontext(ctx); /* set new context */
262	greg	2.6	n = strlen(context); /* tack on old */
263	greg	2.11	if (n+strlen(oldcontext) > MAXCNTX) {
264			strncpy(context+n, oldcontext, MAXCNTX-n);
265			context[MAXCNTX] = '\0';
266	greg	2.6	} else
267			strcpy(context+n, oldcontext);
268			return(context);
269			}
270
271
272			char *
273	schorsch	2.16	popcontext(void) /* pop off top context */
274	greg	2.6	{
275	greg	2.25	char cp1, cp2;
276	greg	2.6
277			if (!context[0]) /* nothing left to pop */
278			return(context);
279			cp2 = context; /* find mark */
280			while (++cp2 && cp2 != CNTXMARK)
281			;
282			cp1 = context; /* copy tail to front */
283	schorsch	2.20	while ( (cp1++ = cp2++) )
284	greg	2.6	;
285	greg	1.13	return(context);
286			}
287
288
289			char *
290	schorsch	2.16	qualname( /* get qualified name */
291	greg	2.25	char *nam,
292	schorsch	2.16	int lvl
293			)
294	greg	1.13	{
295	schorsch	2.17	static char nambuf[RMAXWORD+1];
296	greg	2.25	char cp = nambuf, cpp;
297	greg	1.17	/* check for explicit local */
298	greg	1.15	if (*nam == CNTXMARK)
299	greg	1.17	if (lvl > 0) /* only action is to refuse search */
300			return(NULL);
301			else
302			nam++;
303			else if (nam == nambuf) /* check for repeat call */
304			return(lvl > 0 ? NULL : nam);
305	greg	1.13	/* copy name to static buffer */
306			while (*nam) {
307	schorsch	2.17	if (cp >= nambuf+RMAXWORD)
308	greg	1.13	goto toolong;
309	greg	1.17	cp++ = nam++;
310	greg	1.13	}
311	greg	1.17	/* check for explicit global */
312			if (cp > nambuf && cp[-1] == CNTXMARK) {
313	greg	1.13	if (lvl > 0)
314	greg	1.17	return(NULL);
315			*--cp = '\0';
316			return(nambuf); /* already qualified */
317			}
318			cpp = context; /* else skip the requested levels */
319			while (lvl-- > 0) {
320			if (!*cpp)
321			return(NULL); /* return NULL if past global level */
322			while (++cpp && cpp != CNTXMARK)
323			;
324			}
325	greg	1.13	while (cpp) { / copy context to static buffer */
326	schorsch	2.17	if (cp >= nambuf+RMAXWORD)
327	greg	1.13	goto toolong;
328			cp++ = cpp++;
329			}
330	greg	1.18	toolong:
331	greg	1.13	*cp = '\0';
332			return(nambuf); /* return qualified name */
333			}
334
335
336	greg	2.12	int
337	schorsch	2.16	incontext( /* is qualified name in current context? */
338	greg	2.25	char *qn
339	schorsch	2.16	)
340	greg	1.14	{
341	greg	2.9	if (!context[0]) /* global context accepts all */
342			return(1);
343	greg	1.14	while (qn && qn != CNTXMARK) /* find context mark */
344	greg	1.19	qn++;
345	greg	1.14	return(!strcmp(qn, context));
346			}
347
348
349	greg	2.12	void
350	schorsch	2.16	chanout( /* set output channels */
351			void (*cs)(int n, double v)
352			)
353	greg	1.1	{
354	greg	2.25	EPNODE *ep;
355	greg	1.1
356			for (ep = outchan; ep != NULL; ep = ep->sibling)
357	greg	1.6	(*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling));
358	greg	1.1
359			}
360
361
362	greg	2.12	void
363	schorsch	2.16	dcleanup( /* clear definitions (0->vars,1->output,2->consts) */
364			int lvl
365			)
366	greg	1.1	{
367	greg	2.25	int i;
368			VARDEF *vp;
369			EPNODE *ep;
370	greg	1.14	/* if context is global, clear all */
371	greg	1.1	for (i = 0; i < NHASH; i++)
372			for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
373	schorsch	2.19	if (incontext(vp->name)) {
374	greg	1.14	if (lvl >= 2)
375			dremove(vp->name);
376			else
377			dclear(vp->name);
378	schorsch	2.19	}
379	greg	1.12	if (lvl >= 1) {
380	greg	1.9	for (ep = outchan; ep != NULL; ep = ep->sibling)
381			epfree(ep);
382			outchan = NULL;
383			}
384	greg	1.1	}
385
386
387			EPNODE *
388	schorsch	2.16	dlookup( /* look up a definition */
389			char *name
390			)
391	greg	1.1	{
392	greg	2.25	VARDEF *vp;
393	greg	1.1
394			if ((vp = varlookup(name)) == NULL)
395	greg	2.4	return(NULL);
396	greg	1.1	return(vp->def);
397			}
398
399
400			VARDEF *
401	schorsch	2.16	varlookup( /* look up a variable */
402			char *name
403			)
404	greg	1.1	{
405	greg	2.4	int lvl = 0;
406	greg	2.25	char *qname;
407			VARDEF *vp;
408	greg	2.4	/* find most qualified match */
409	greg	1.13	while ((qname = qualname(name, lvl++)) != NULL)
410			for (vp = hashtbl[hash(qname)]; vp != NULL; vp = vp->next)
411			if (!strcmp(vp->name, qname))
412			return(vp);
413	greg	1.1	return(NULL);
414			}
415
416
417			VARDEF *
418	schorsch	2.16	varinsert( /* get a link to a variable */
419			char *name
420			)
421	greg	1.1	{
422	greg	2.25	VARDEF *vp;
423	greg	2.4	int hv;
424	greg	1.1
425	greg	1.13	if ((vp = varlookup(name)) != NULL) {
426			vp->nlinks++;
427			return(vp);
428			}
429	greg	2.3	vp = (VARDEF *)emalloc(sizeof(VARDEF));
430			vp->lib = liblookup(name);
431			if (vp->lib == NULL) /* if name not in library */
432	greg	1.16	name = qualname(name, 0); /* use fully qualified version */
433	greg	1.1	hv = hash(name);
434			vp->name = savestr(name);
435			vp->nlinks = 1;
436			vp->def = NULL;
437			vp->next = hashtbl[hv];
438			hashtbl[hv] = vp;
439			return(vp);
440			}
441	greg	2.2
442
443	greg	2.12	void
444	schorsch	2.16	libupdate( /* update library links */
445			char *fn
446			)
447	greg	2.2	{
448	greg	2.25	int i;
449			VARDEF *vp;
450	greg	2.2	/* if fn is NULL then relink all */
451			for (i = 0; i < NHASH; i++)
452			for (vp = hashtbl[i]; vp != NULL; vp = vp->next)
453	greg	2.33	if ((vp->lib != NULL) \| (fn == NULL) \|\| !strcmp(fn, vp->name))
454	greg	2.2	vp->lib = liblookup(vp->name);
455			}
456	greg	1.1
457
458	greg	2.12	void
459	schorsch	2.16	varfree( /* release link to variable */
460	greg	2.25	VARDEF *ln
461	schorsch	2.16	)
462	greg	1.1	{
463	greg	2.25	VARDEF *vp;
464	greg	2.4	int hv;
465	greg	1.1
466			if (--ln->nlinks > 0)
467	greg	2.4	return; /* still active */
468	greg	1.1
469			hv = hash(ln->name);
470			vp = hashtbl[hv];
471			if (vp == ln)
472	greg	2.4	hashtbl[hv] = vp->next;
473	greg	1.1	else {
474	greg	2.4	while (vp->next != ln) /* must be in list */
475			vp = vp->next;
476			vp->next = ln->next;
477	greg	1.1	}
478			freestr(ln->name);
479			efree((char *)ln);
480			}
481
482
483			EPNODE *
484	schorsch	2.16	dfirst(void) /* return pointer to first definition */
485	greg	1.1	{
486			htndx = 0;
487			htpos = NULL;
488			ochpos = outchan;
489			return(dnext());
490			}
491
492
493			EPNODE *
494	schorsch	2.16	dnext(void) /* return pointer to next definition */
495	greg	1.1	{
496	greg	2.25	EPNODE *ep;
497			char *nm;
498	greg	1.1
499			while (htndx < NHASH) {
500	greg	2.4	if (htpos == NULL)
501			htpos = hashtbl[htndx++];
502			while (htpos != NULL) {
503			ep = htpos->def;
504	greg	1.19	nm = htpos->name;
505	greg	2.4	htpos = htpos->next;
506			if (ep != NULL && incontext(nm))
507			return(ep);
508			}
509	greg	1.1	}
510			if ((ep = ochpos) != NULL)
511	greg	2.4	ochpos = ep->sibling;
512	greg	1.1	return(ep);
513			}
514
515
516			EPNODE *
517	schorsch	2.16	dpop( /* pop a definition */
518			char *name
519			)
520	greg	1.1	{
521	greg	2.25	VARDEF *vp;
522			EPNODE *dp;
523	greg	1.1
524			if ((vp = varlookup(name)) == NULL \|\| vp->def == NULL)
525	greg	2.4	return(NULL);
526	greg	1.1	dp = vp->def;
527			vp->def = dp->sibling;
528			varfree(vp);
529			return(dp);
530			}
531
532
533	greg	2.12	void
534	schorsch	2.16	dpush( /* push on a definition */
535			char *nm,
536	greg	2.25	EPNODE *ep
537	schorsch	2.16	)
538	greg	1.1	{
539	greg	2.25	VARDEF *vp;
540	greg	1.1
541	greg	1.13	vp = varinsert(nm);
542	greg	1.1	ep->sibling = vp->def;
543			vp->def = ep;
544			}
545
546
547	greg	2.12	void
548	schorsch	2.16	addchan( /* add an output channel assignment */
549			EPNODE *sp
550			)
551	greg	1.1	{
552	greg	2.4	int ch = sp->v.kid->v.chan;
553	greg	2.25	EPNODE ep, epl;
554	greg	1.1
555			for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling)
556			if (ep->v.kid->v.chan >= ch) {
557			if (epl != NULL)
558			epl->sibling = sp;
559			else
560			outchan = sp;
561			if (ep->v.kid->v.chan > ch)
562			sp->sibling = ep;
563			else {
564			sp->sibling = ep->sibling;
565			epfree(ep);
566			}
567			return;
568			}
569			if (epl != NULL)
570			epl->sibling = sp;
571			else
572			outchan = sp;
573			sp->sibling = NULL;
574
575			}
576
577
578	greg	2.12	void
579	schorsch	2.16	getstatement(void) /* get next statement */
580	greg	1.1	{
581	greg	2.25	EPNODE *ep;
582	greg	1.13	char *qname;
583	greg	2.25	VARDEF *vdef;
584	greg	1.1
585			if (nextc == ';') { /* empty statement */
586			scan();
587			return;
588			}
589	greg	2.12	if (esupport&E_OUTCHAN &&
590			nextc == '$') { /* channel assignment */
591	greg	1.1	ep = getchan();
592			addchan(ep);
593	greg	2.12	} else { /* ordinary definition */
594	greg	1.1	ep = getdefn();
595	greg	1.13	qname = qualname(dname(ep), 0);
596	schorsch	2.19	if (esupport&E_REDEFW && (vdef = varlookup(qname)) != NULL) {
597	greg	2.7	if (vdef->def != NULL && epcmp(ep, vdef->def)) {
598	greg	1.16	wputs(qname);
599			if (vdef->def->type == ':')
600			wputs(": redefined constant expression\n");
601			else
602			wputs(": redefined\n");
603	greg	2.12	} else if (ep->v.kid->type == FUNC && vdef->lib != NULL) {
604	greg	1.16	wputs(qname);
605			wputs(": definition hides library function\n");
606			}
607	schorsch	2.19	}
608	greg	1.10	if (ep->type == ':')
609	greg	1.13	dremove(qname);
610	greg	1.10	else
611	greg	1.13	dclear(qname);
612			dpush(qname, ep);
613	greg	1.1	}
614			if (nextc != EOF) {
615			if (nextc != ';')
616			syntax("';' expected");
617			scan();
618			}
619			}
620
621
622			EPNODE *
623	schorsch	2.16	getdefn(void)
624			/* A -> SYM = E1 */
625			/* SYM : E1 */
626			/* FUNC(SYM,..) = E1 */
627			/* FUNC(SYM,..) : E1 */
628	greg	1.1	{
629	greg	2.25	EPNODE ep1, ep2;
630	greg	1.1
631	greg	2.33	if (!isalpha(nextc) & (nextc != CNTXMARK))
632	greg	1.1	syntax("illegal variable name");
633
634			ep1 = newnode();
635			ep1->type = SYM;
636			ep1->v.name = savestr(getname());
637
638	greg	2.12	if (esupport&E_FUNCTION && nextc == '(') {
639	greg	1.1	ep2 = newnode();
640			ep2->type = FUNC;
641			addekid(ep2, ep1);
642			ep1 = ep2;
643			do {
644			scan();
645			if (!isalpha(nextc))
646	greg	2.24	syntax("illegal parameter name");
647	greg	1.1	ep2 = newnode();
648			ep2->type = SYM;
649			ep2->v.name = savestr(getname());
650	greg	2.29	if (strchr(ep2->v.name, CNTXMARK) != NULL)
651			syntax("illegal parameter name");
652	greg	1.1	addekid(ep1, ep2);
653			} while (nextc == ',');
654			if (nextc != ')')
655			syntax("')' expected");
656			scan();
657			curfunc = ep1;
658	greg	2.10	}
659	greg	1.1
660	greg	2.33	if ((nextc != '=') & (nextc != ':'))
661	greg	1.8	syntax("'=' or ':' expected");
662	greg	1.1
663			ep2 = newnode();
664	greg	1.8	ep2->type = nextc;
665			scan();
666	greg	1.1	addekid(ep2, ep1);
667			addekid(ep2, getE1());
668
669	greg	2.12	if (ep1->type == SYM && ep1->sibling->type != NUM) {
670	greg	1.1	ep1 = newnode();
671	greg	2.23	ep1->type = CLKT;
672	greg	2.8	ep1->v.tick = 0;
673	greg	1.1	addekid(ep2, ep1);
674			ep1 = newnode();
675			ep1->type = NUM;
676			addekid(ep2, ep1);
677			}
678	greg	2.10	curfunc = NULL;
679	greg	1.1
680			return(ep2);
681			}
682
683
684			EPNODE *
685	schorsch	2.16	getchan(void) /* A -> $N = E1 */
686	greg	1.1	{
687	greg	2.25	EPNODE ep1, ep2;
688	greg	1.1
689			if (nextc != '$')
690			syntax("missing '$'");
691			scan();
692
693			ep1 = newnode();
694			ep1->type = CHAN;
695			ep1->v.chan = getinum();
696
697			if (nextc != '=')
698			syntax("'=' expected");
699			scan();
700
701			ep2 = newnode();
702			ep2->type = '=';
703			addekid(ep2, ep1);
704			addekid(ep2, getE1());
705
706			return(ep2);
707			}
708
709
710
711			/*
712			* The following routines are for internal use only:
713			*/
714
715
716	schorsch	2.18	static double /* evaluate a variable */
717	greg	2.28	dvalue(char name, EPNODE d)
718	greg	1.1	{
719	greg	2.25	EPNODE ep1, ep2;
720	greg	1.1
721			if (d == NULL \|\| d->v.kid->type != SYM) {
722			eputs(name);
723			eputs(": undefined variable\n");
724			quit(1);
725			}
726			ep1 = d->v.kid->sibling; /* get expression */
727	greg	1.5	if (ep1->type == NUM)
728			return(ep1->v.num); /* return if number */
729	greg	2.28	if (esupport&E_RCONST && d->type == ':') {
730			wputs(name);
731			wputs(": assigned non-constant value\n");
732			}
733	greg	1.1	ep2 = ep1->sibling; /* check time */
734	greg	2.12	if (eclock >= MAXCLOCK)
735			eclock = 1; /* wrap clock counter */
736			if (ep2->v.tick < MAXCLOCK &&
737	schorsch	2.20	(ep2->v.tick == 0) \| (ep2->v.tick != eclock)) {
738	greg	2.12	ep2->v.tick = d->type == ':' ? MAXCLOCK : eclock;
739	greg	1.1	ep2 = ep2->sibling;
740	greg	1.5	ep2->v.num = evalue(ep1); /* needs new value */
741	greg	1.1	} else
742	greg	1.5	ep2 = ep2->sibling; /* else reuse old value */
743	greg	1.1
744			return(ep2->v.num);
745			}