implement Cgi; include "sys.m";	sys: Sys;	sprint: import sys;include "bufio.m";	bufio: Bufio;	Iobuf: import bufio;include "string.m";	str: String;include "env.m";	env: Env;include "dict.m";	dict: Dictionary;	Dict: import dict;include "cgi.m";  init(){	sys = load Sys Sys->PATH;	bufio = load Bufio Bufio->PATH;	str = load String String->PATH;	env = load Env Env->PATH;	dict = load Dictionary Dictionary->PATH;}  Fields.get(f: self ref Fields, name: string): string{	for(l := f.l; l != nil; l = tl l) {		(k, v, nil) := hd l;		if(k == name)			return v;	}	return nil;} Fields.getbytes(f: self ref Fields, name: string): array of byte{	for(l := f.l; l != nil; l = tl l) {		(k, nil, v) := hd l;		if(k == name)			return v;	}	return nil;} Fields.getdefault(f: self ref Fields, name, default: string): string{	for(l := f.l; l != nil; l = tl l) {		(k, v, nil) := hd l;		if(k == name)			return v;	}	return default;} Fields.getlist(f: self ref Fields, name: string): list of string{	r: list of string;	for(l := f.l; l != nil; l = tl l) {		(k, v, nil) := hd l;		if(k == name)			r = v :: r;	}	return r;} Fields.all(f: self ref Fields): list of (string, string, array of byte){	return f.l;} Fields.has(f: self ref Fields, name: string): int{	for(l := f.l; l != nil; l = tl l)		if((hd l).t0 == name)			return 1;	return 0;} hex(c: int): int{	if(c >= '0' && c <= '9')		return c - '0';	if(c >= 'A' && c <= 'F')		c += 'a' - 'A';	if(c >= 'a' && c <= 'f')		return 10 + c - 'a';	return -1;} decodebytes(s: string): array of byte{	sa := array of byte s;	ra := array[len sa] of byte;	si := 0;	ri := 0;	while(si < len sa) {		c: byte;		if(sa[si] == byte '%') {			if(si+2 < len sa) {				h1 := hex(int sa[si+1]);				h2 := hex(int sa[si+2]);				if(h1 < 0 || h2 < 0)					return nil;				c = byte ((h1 << 4) | h2);				si += 3;			} else				return nil;		} else if(sa[si] == byte '+') {			c = byte ' ';			si += 1;		} else {			c = sa[si];			si += 1;		}		ra[ri++] = c;	}	return ra[:ri];} decode(s: string): string{	return string decodebytes(s);} encodepath(s: string): string{	return _encode(s, "/");} encode(s: string): string{	return _encode(s, "");} _encode(s: string, okayspecial: string): string{	a := array of byte s;	r := "";	okay := "a-zA-Z0-9*_.-";	for(i := 0; i < len a; i++) {		c := int a[i];		if(str->in(c, okay) || str->in(c, okayspecial))			r += sprint("%c", c);		else if(c == ' ')			r += "+";		else			r += sprint("%%%02X", c);	}	return r;} pack(l: list of (string, string)): string{	r := "";	first := 1;	while(l != nil) {		(k, v) := hd l;		if(!first)			r += sprint("&");		r += sprint("%s=%s", encode(k), encode(v));		l = tl l;		first = 0;	}	return r;} htmlescape(s: string): string{	r := "";	for(i := 0; i < len s; i++)		case s[i] {		'<' =>	r += "&lt;";		'>' =>	r += "&gt;";		'&' =>	r += "&amp;";		'"' =>	r += "&quot;";		* =>	r += s[i:i+1];		}	return r;} tokenize(s, delims: string): list of string{	if(s == "")		return nil;	(token, remain) := str->splitstrl(s, delims);	if(remain != "")		remain = remain[1:];	return token :: tokenize(remain, delims);} readstr(fd: ref Sys->FD, n: int): string{        a := array[0] of byte;        buf := array[1024] of byte;        while(n > 0) {		want := len buf;		if(want > n)			want = n;                have := sys->read(fd, buf, want);                if(have == 0)			# premature eof                        return nil;                if(have < 0)			# xxx warn                        return nil;		anew := array[len a+have] of byte;		anew[:] = a;		anew[len a:] = buf[:have];		a = anew;                n -= have;        }        return string a;} # xxxreadall(fd: ref Sys->FD): string{        a := array[0] of byte;        buf := array[1024] of byte;        for(;;) {                have := sys->read(fd, buf, len buf);                if(have == 0)                        break;                if(have < 0)			# xxx error                        return nil;		anew := array[len a+have] of byte;		anew[:] = a;		anew[len a:] = buf[:have];		a = anew;        }        return string a;} unpackenv(): ref Fields{	qs := "";	method := env->getenv("REQUEST_METHOD");	if(method == nil || method == "GET" || method == "HEAD") {		qs = env->getenv("QUERY_STRING");	} else if(method == "POST") {		content := env->getenv("CONTENT_TYPE");		if(content != nil && content != "application/x-www-form-urlencoded")			# xxx it is probably multipart/form-data (used for files)			return nil;		length := env->getenv("CONTENT_LENGTH");		if(length != nil)			qs = readstr(sys->fildes(0), int length);		else			qs = readall(sys->fildes(0));	}	return unpack(qs);} unpack(s: string): ref Fields{	l: list of (string, string, array of byte);	pairs := tokenize(s, "&");	while(pairs != nil) {		pair := hd pairs;		pairs = tl pairs;		(k, v) := str->splitstrl(pair, "=");		if(v == nil)			continue;		v = v[1:];		k = decode(k);		vd := decodebytes(v);		l = (k, string vd, vd)::l;	}	return ref Fields(l);}