/* extensible Strings */typedef struct String {	char *base;	/* base of String */	char *end;	/* end of allocated space+1 */	char *ptr;	/* ptr into String */} String; #define s_putc(s,c)\	if (s->ptr<s->end) *(s->ptr)++ = c; else s_grow(s,c)#define s_terminate(s)\	if (s->ptr<s->end) *s->ptr = 0; else{ s_grow(s,0); s->ptr--; }#define s_restart(s) (s->ptr = s->base , s)#define s_reset(s) (s ? (*(s->ptr = s->base) = '\0' , s) : s_new())#define s_clone(s) s_copy(s->ptr)#define s_to_c(s) s->base extern String	*s_alloc(void);extern void	s_simplegrow(String*, int);extern int	s_grow(String*, int);extern String	*s_new(void);extern void	s_free(String*);extern String	*s_append(String*, char*);extern String	*s_nappend(String*, char*, int);extern String	*s_array(char*, int);extern String	*s_copy(char*);extern String	*s_parse(String*, String*);extern void	s_tolower(String*); #ifdef BGETCextern int	s_read(Biobuf*, String*, int);extern char	*s_read_line(Biobuf*, String*);extern char	*s_getline(Biobuf*, String*);#endif BGETC