#include	"u.h"#include	"lib.h"#include	"dat.h"#include	"fns.h"#include	"error.h" /* * Generous estimate of number of fields, including terminal nil pointer */static intncmdfield(char *p, int n){	int white, nwhite;	char *ep;	int nf; 	if(p == nil)		return 1; 	nf = 0;	ep = p+n;	white = 1;	/* first text will start field */	while(p < ep){		nwhite = (strchr(" \t\r\n", *p++ & 0xFF) != 0);	/* UTF is irrelevant */		if(white && !nwhite)	/* beginning of field */			nf++;		white = nwhite;	}	return nf+1;	/* +1 for nil */} /* *  parse a command written to a device */Cmdbuf*parsecmd(char *p, int n){	Cmdbuf *volatile cb;	int nf;	char *sp; 	nf = ncmdfield(p, n); 	/* allocate Cmdbuf plus string pointers plus copy of string including \0 */	sp = smalloc(sizeof(*cb) + nf * sizeof(char*) + n + 1);	cb = (Cmdbuf*)sp;	cb->f = (char**)(&cb[1]);	cb->buf = (char*)(&cb->f[nf]); 	if(up!=nil && waserror()){		free(cb);		nexterror();	}	memmove(cb->buf, p, n);	if(up != nil)		poperror(); 	/* dump new line and null terminate */	if(n > 0 && cb->buf[n-1] == '\n')		n--;	cb->buf[n] = '\0'; 	cb->nf = tokenize(cb->buf, cb->f, nf-1);	cb->f[cb->nf] = nil; 	return cb;} /* * Reconstruct original message, for error diagnostic */voidcmderror(Cmdbuf *cb, char *s){	int i;	char *p, *e; 	p = up->genbuf;	e = p+ERRMAX-10;	p = seprint(p, e, "%s \"", s);	for(i=0; i<cb->nf; i++){		if(i > 0)			p = seprint(p, e, " ");		p = seprint(p, e, "%q", cb->f[i]);	}	strcpy(p, "\"");	error(up->genbuf);} /* * Look up entry in table */Cmdtab*lookupcmd(Cmdbuf *cb, Cmdtab *ctab, int nctab){	int i;	Cmdtab *ct; 	if(cb->nf == 0)		error("empty control message"); 	for(ct = ctab, i=0; i<nctab; i++, ct++){		if(strcmp(ct->cmd, "*") !=0)	/* wildcard always matches */		if(strcmp(ct->cmd, cb->f[0]) != 0)			continue;		if(ct->narg != 0 && ct->narg != cb->nf)			cmderror(cb, Ecmdargs);		return ct;	} 	cmderror(cb, "unknown control message");	return nil;}