From f08fdedcee12c06e3ce9ac9bec363915978e8289 Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Sun, 23 Nov 2003 18:04:08 +0000
Subject: Plan 9's rc.

not a clear win over byron's,
but at least it has the right syntax.
---
 src/cmd/rc/getflags.c | 217 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 217 insertions(+)
 create mode 100644 src/cmd/rc/getflags.c

(limited to 'src/cmd/rc/getflags.c')

diff --git a/src/cmd/rc/getflags.c b/src/cmd/rc/getflags.c
new file mode 100644
index 00000000..c452067f
--- /dev/null
+++ b/src/cmd/rc/getflags.c
@@ -0,0 +1,217 @@
+/*% cyntax -DTEST % && cc -DTEST -go # %
+ */
+#include "rc.h"
+#include "getflags.h"
+#include "fns.h"
+char *flagset[]={"<flag>"};
+char **flag[NFLAG];
+char cmdline[NCMDLINE+1];
+char *cmdname;
+static char *flagarg="";
+static void reverse(char**, char**);
+static int scanflag(int, char*);
+static void errn(char*, int);
+static void errs(char*);
+static void errc(int);
+static int reason;
+#define	RESET	1
+#define	FEWARGS	2
+#define	FLAGSYN	3
+#define	BADFLAG	4
+static int badflag;
+int getflags(int argc, char *argv[], char *flags, int stop)
+{
+	char *s, *t;
+	int i, j, c, count;
+	flagarg=flags;
+	if(cmdname==0) cmdname=argv[0];
+	s=cmdline;
+	for(i=0;i!=argc;i++){
+		for(t=argv[i];*t;t++)
+			if(s!=&cmdline[NCMDLINE])
+				*s++=*t;
+		if(i!=argc-1 && s!=&cmdline[NCMDLINE])
+			*s++=' ';
+	}
+	*s='\0';
+	i=1;
+	while(i!=argc){
+		if(argv[i][0]!='-' || argv[i][1]=='\0'){
+			if(stop) return argc;
+			i++;
+			continue;
+		}
+		s=argv[i]+1;
+		while(*s){
+			c=*s++;
+			count=scanflag(c, flags);
+			if(count==-1) return -1;
+			if(flag[c]){ reason=RESET; badflag=c; return -1; }
+			if(count==0){
+				flag[c]=flagset;
+				if(*s=='\0'){
+					for(j=i+1;j<=argc;j++)
+						argv[j-1]=argv[j];
+					--argc;
+				}
+			}
+			else{
+				if(*s=='\0'){
+					for(j=i+1;j<=argc;j++)
+						argv[j-1]=argv[j];
+					--argc;
+					s=argv[i];
+				}
+				if(argc-i<count){
+					reason=FEWARGS;
+					badflag=c;
+					return -1;
+				}
+				reverse(argv+i, argv+argc);
+				reverse(argv+i, argv+argc-count);
+				reverse(argv+argc-count+1, argv+argc);
+				argc-=count;
+				flag[c]=argv+argc+1;
+				flag[c][0]=s;
+				s="";
+			}
+		}
+	}
+	return argc;
+}
+static void reverse(char **p, char **q)
+{
+	char *t;
+	for(;p<q;p++,--q){ t=*p; *p=*q; *q=t; }
+}
+static int scanflag(int c, char *f)
+{
+	int fc, count;
+	if(0<=c && c<NFLAG) while(*f){
+		if(*f==' '){
+			f++;
+			continue;
+		}
+		fc=*f++;
+		if(*f==':'){
+			f++;
+			if(*f<'0' || '9'<*f){ reason=FLAGSYN; return -1; }
+			count=0;
+			while('0'<=*f && *f<='9') count=count*10+*f++-'0';
+		}
+		else
+			count=0;
+		if(*f=='['){
+			do{
+				f++;
+				if(*f=='\0'){ reason=FLAGSYN; return -1; }
+			}while(*f!=']');
+			f++;
+		}
+		if(c==fc) return count;
+	}
+	reason=BADFLAG;
+	badflag=c;
+	return -1;
+}
+void usage(char *tail)
+{
+	char *s, *t, c;
+	int count, nflag=0;
+	switch(reason){
+	case RESET:
+		errs("Flag -");
+		errc(badflag);
+		errs(": set twice\n");
+		break;
+	case FEWARGS:
+		errs("Flag -");
+		errc(badflag);
+		errs(": too few arguments\n");
+		break;
+	case FLAGSYN:
+		errs("Bad argument to getflags!\n");
+		break;
+	case BADFLAG:
+		errs("Illegal flag -");
+		errc(badflag);
+		errc('\n');
+		break;
+	}
+	errs("Usage: ");
+	errs(cmdname);
+	for(s=flagarg;*s;){
+		c=*s;
+		if(*s++==' ') continue;
+		if(*s==':'){
+			s++;
+			count=0;
+			while('0'<=*s && *s<='9') count=count*10+*s++-'0';
+		}
+		else count=0;
+		if(count==0){
+			if(nflag==0) errs(" [-");
+			nflag++;
+			errc(c);
+		}
+		if(*s=='['){
+			s++;
+			while(*s!=']' && *s!='\0') s++;
+			if(*s==']') s++;
+		}
+	}
+	if(nflag) errs("]");
+	for(s=flagarg;*s;){
+		c=*s;
+		if(*s++==' ') continue;
+		if(*s==':'){
+			s++;
+			count=0;
+			while('0'<=*s && *s<='9') count=count*10+*s++-'0';
+		}
+		else count=0;
+		if(count!=0){
+			errs(" [-");
+			errc(c);
+			if(*s=='['){
+				s++;
+				t=s;
+				while(*s!=']' && *s!='\0') s++;
+				errs(" ");
+				errn(t, s-t);
+				if(*s==']') s++;
+			}
+			else
+				while(count--) errs(" arg");
+			errs("]");
+		}
+		else if(*s=='['){
+			s++;
+			while(*s!=']' && *s!='\0') s++;
+			if(*s==']') s++;
+		}
+	}
+	if(tail){
+		errs(" ");
+		errs(tail);
+	}
+	errs("\n");
+	Exit("bad flags");
+}
+static void errn(char *s, int count)
+{
+	while(count){ errc(*s++); --count; }
+}
+static void errs(char *s)
+{
+	while(*s) errc(*s++);
+}
+#define	NBUF	80
+static char buf[NBUF], *bufp=buf;
+static void errc(int c){
+	*bufp++=c;
+	if(bufp==&buf[NBUF] || c=='\n'){
+		Write(2, buf, bufp-buf);
+		bufp=buf;
+	}
+}
-- 
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