Plan 9's rc.

not a clear win over byron's,
but at least it has the right syntax.

src/cmd/rc/io.c

@@ -0,0 +1,179 @@
+#include "rc.h"
+#include "exec.h"
+#include "io.h"
+#include "fns.h"
+int pfmtnest=0;
+void pfmt(io *f, char *fmt, ...){
+	va_list ap;
+	char err[ERRMAX];
+	va_start(ap, fmt);
+	pfmtnest++;
+	for(;*fmt;fmt++)
+		if(*fmt!='%') pchr(f, *fmt);
+		else switch(*++fmt){
+		case '\0': va_end(ap); return;
+		case 'c': pchr(f, va_arg(ap, int)); break;
+		case 'd': pdec(f, va_arg(ap, int)); break;
+		case 'o': poct(f, va_arg(ap, unsigned)); break;
+		case 'p': phex(f, (long)va_arg(ap, char *)); break; /*unportable*/
+		case 'Q': pquo(f, va_arg(ap, char *)); break;
+		case 'q': pwrd(f, va_arg(ap, char *)); break;
+		case 'r': errstr(err, sizeof err); pstr(f, err); break;
+		case 's': pstr(f, va_arg(ap, char *)); break;
+		case 't': pcmd(f, va_arg(ap, struct tree *)); break;
+		case 'v': pval(f, va_arg(ap, struct word *)); break;
+		default: pchr(f, *fmt); break;
+		}
+	va_end(ap);
+	if(--pfmtnest==0) flush(f);
+}
+void pchr(io *b, int c)
+{
+	if(b->bufp==b->ebuf) fullbuf(b, c);
+	else *b->bufp++=c;
+}
+int rchr(io *b)
+{
+	if(b->bufp==b->ebuf) return emptybuf(b);
+	return *b->bufp++ & 0xFF;
+}
+
+void pquo(io *f, char *s)
+{
+	pchr(f, '\'');
+	for(;*s;s++)
+		if(*s=='\'') pfmt(f, "''");
+		else pchr(f, *s);
+	pchr(f, '\'');
+}
+void pwrd(io *f, char *s)
+{
+	char *t;
+	for(t=s;*t;t++) if(!wordchr(*t)) break;
+	if(t==s || *t) pquo(f, s);
+	else pstr(f, s);
+}
+void phex(io *f, long p)
+{
+	int n;
+	for(n=28;n>=0;n-=4) pchr(f, "0123456789ABCDEF"[(p>>n)&0xF]);
+}
+void pstr(io *f, char *s)
+{
+	if(s==0) s="(null)";
+	while(*s) pchr(f, *s++);
+}
+void pdec(io *f, long n)
+{
+	if(n<0){
+		n=-n;
+		if(n>=0){
+			pchr(f, '-');
+			pdec(f, n);
+			return;
+		}
+		/* n is two's complement minimum integer */
+		n=1-n;
+		pchr(f, '-');
+		pdec(f, n/10);
+		pchr(f, n%10+'1');
+		return;
+	}
+	if(n>9) pdec(f, n/10);
+	pchr(f, n%10+'0');
+}
+void poct(io *f, ulong n)
+{
+	if(n>7) poct(f, n>>3);
+	pchr(f, (n&7)+'0');
+}
+void pval(io *f, word *a)
+{
+	if(a){
+		while(a->next && a->next->word){
+			pwrd(f, a->word);
+			pchr(f, ' ');
+			a=a->next;
+		}
+		pwrd(f, a->word);
+	}
+}
+int fullbuf(io *f, int c)
+{
+	flush(f);
+	return *f->bufp++=c;
+}
+void flush(io *f)
+{
+	int n;
+	char *s;
+	if(f->strp){
+		n=f->ebuf-f->strp;
+		f->strp=realloc(f->strp, n+101);
+		if(f->strp==0) panic("Can't realloc %d bytes in flush!", n+101);
+		f->bufp=f->strp+n;
+		f->ebuf=f->bufp+100;
+		for(s=f->bufp;s<=f->ebuf;s++) *s='\0';
+	}
+	else{
+		n=f->bufp-f->buf;
+		if(n && Write(f->fd, f->buf, n) < 0){
+			Write(3, "Write error\n", 12);
+			if(ntrap) dotrap();
+		}
+		f->bufp=f->buf;
+		f->ebuf=f->buf+NBUF;
+	}
+}
+io *openfd(int fd){
+	io *f=new(struct io);
+	f->fd=fd;
+	f->bufp=f->ebuf=f->buf;
+	f->strp=0;
+	return f;
+}
+io *openstr(void){
+	io *f=new(struct io);
+	char *s;
+	f->fd=-1;
+	f->bufp=f->strp=emalloc(101);
+	f->ebuf=f->bufp+100;
+	for(s=f->bufp;s<=f->ebuf;s++) *s='\0';
+	return f;
+}
+/*
+ * Open a corebuffer to read.  EOF occurs after reading len
+ * characters from buf.
+ */
+io *opencore(char *s, int len)
+{
+	io *f=new(struct io);
+	char *buf=emalloc(len);
+	f->fd= -1 /*open("/dev/null", 0)*/;
+	f->bufp=f->strp=buf;
+	f->ebuf=buf+len;
+	Memcpy(buf, s, len);
+	return f;
+}
+void rewind(io *io)
+{
+	if(io->fd==-1) io->bufp=io->strp;
+	else{
+		io->bufp=io->ebuf=io->buf;
+		Seek(io->fd, 0L, 0);
+	}
+}
+void closeio(io *io)
+{
+	if(io->fd>=0) close(io->fd);
+	if(io->strp) efree(io->strp);
+	efree((char *)io);
+}
+int emptybuf(io *f)
+{
+	int n;
+	if(f->fd==-1 || (n=Read(f->fd, f->buf, NBUF))<=0) return EOF;
+	f->bufp=f->buf;
+	f->ebuf=f->buf+n;
+	return *f->bufp++&0xff;
+}