/*
 *	Macro control for make
 */


#include "h.h"


struct macro   *macrohead;


struct macro   *
getmp(name)
    char           *name;
{
    register struct macro *rp;

    for (rp = macrohead; rp; rp = rp->m_next)
	if (strcmp(name, rp->m_name) == 0)
	    return rp;
    return (struct macro *) 0;
}


char           *
getmacro(name)
    char           *name;
{
    struct macro   *mp;

    if (mp = getmp(name))
	return mp->m_val;
    else
	return "";
}


struct macro   *
setmacro(name, val)
    char           *name;
    char           *val;
{
    register struct macro *rp;
    register char  *cp;


    /* Replace macro definition if it exists  */
    for (rp = macrohead; rp; rp = rp->m_next)
	if (strcmp(name, rp->m_name) == 0) {
	    free(rp->m_val);	/* Free space from old  */
	    break;
	}
    if (!rp) {			/* If not defined, allocate space for new  */
	if ((rp = (struct macro *) malloc(sizeof(struct macro)))
	    == (struct macro *) 0)
	    fatal("No memory for macro");

	rp->m_next = macrohead;
	macrohead = rp;
	rp->m_flag = FALSE;

	if ((cp = malloc((unsigned) strlen(name) + 1)) == (char *) 0)
	    fatal("No memory for macro");
	strcpy(cp, name);
	rp->m_name = cp;
    }
    if ((cp = malloc((unsigned) strlen(val) + 1)) == (char *) 0)
	fatal("No memory for macro");
    strcpy(cp, val);		/* Copy in new value  */
    rp->m_val = cp;

    return rp;
}


/*
 *	Do the dirty work for expand
 */
void
doexp(to, from, len, buf)
    char          **to;
    char           *from;
    int            *len;
    char           *buf;
{
    register char  *rp;
    register char  *p;
    register char  *q;
    register struct macro *mp;


    rp = from;
    p = *to;
    while (*rp) {
	if (*rp != '$') {
	    *p++ = *rp++;
	    (*len)--;
	} else {
	    q = buf;
	    if (*++rp == '{')
		while (*++rp && *rp != '}')
		    *q++ = *rp;
	    else if (*rp == '(')
		while (*++rp && *rp != ')')
		    *q++ = *rp;
	    else if (!*rp) {
		*p++ = '$';
		break;
	    } else
		*q++ = *rp;
	    *q = '\0';
	    if (*rp)
		rp++;
	    if (!(mp = getmp(buf)))
		mp = setmacro(buf, "");
	    if (mp->m_flag)
		fatal("Infinitely recursive macro %s", mp->m_name);
	    mp->m_flag = TRUE;
	    *to = p;
	    doexp(to, mp->m_val, len, buf);
	    p = *to;
	    mp->m_flag = FALSE;
	}
	if (*len <= 0)
	    error("Expanded line too line");
    }
    *p = '\0';
    *to = p;
}


/*
 *	Expand any macros in str.
 */
void
expand(str)
    char           *str;
{
    static char     a[LZ];
    static char     b[LZ];
    char           *p = str;
    int             len = LZ - 1;

    strcpy(a, str);
    doexp(&p, a, &len, b);
}