#include <u.h>
#include <libc.h>
#include "base64.h"

void
usage(void)
{
	fprint(2, "base64decode [file]\n");
	exits("usage");
}

static void 
decode(int fd, char *name)
{
	int n, nb;
	long tot;
	char *buf, *outbuf;
	outbuf = nil;
	buf = nil;
	tot = 0;
	for(;;){
		buf = realloc(buf, tot+8192);
		if(buf == nil)
			sysfatal("realloc: %r");
		if((n = read(fd, buf+tot, 8192)) < 0)
			sysfatal("read: %r");
		if(n == 0)
			break;
		tot += n;
	}
	buf[tot] = 0;
	outbuf =  malloc(b64d_size(strlen(buf)));
	nb = b64_decode(buf, strlen(buf), outbuf);
	outbuf[nb] = 0;
	if((n=write(1,  outbuf, strlen(outbuf))) != strlen(outbuf))
		sysfatal("writing bytes failed");
}

void
main(int argc, char **argv)
{
	int fd;
	char *file;
	fd = 0;
	file = "stdin";
	ARGBEGIN{
	default:
		usage();
	}ARGEND
	if(argc != 0 && argc != 1)
		usage();
	if(argc == 1){
		file = argv[0];
 		if((fd = open(file, OREAD)) < 0)
			sysfatal("can'topen %s", file);
	}
	decode(fd, file);
}