unicode.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#include <u.h>
#include <libc.h>
#include <bio.h>

char	usage[] = "unicode { [-t] hex hex ... | hexmin-hexmax ... | [-n] char ... }";
char	hex[] = "0123456789abcdefABCDEF";
int	numout = 0;
int	text = 0;
char	*err;
Biobuf	bout;

char	*range(char*[]);
char	*nums(char*[]);
char	*chars(char*[]);

void
main(int argc, char *argv[])
{
	ARGBEGIN{
	case 'n':
		numout = 1;
		break;
	case 't':
		text = 1;
		break;
	}ARGEND
	Binit(&bout, 1, OWRITE);
	if(argc == 0){
		fprint(2, "usage: %s\n", usage);
		exits("usage");
	}
	if(!numout && utfrune(argv[0], '-'))
		exits(range(argv));
	if(numout || strchr(hex, argv[0][0])==0)
		exits(nums(argv));
	exits(chars(argv));
}

char*
range(char *argv[])
{
	char *q;
	int min, max;
	int i;

	while(*argv){
		q = *argv;
		if(strchr(hex, q[0]) == 0){
    err:
			fprint(2, "unicode: bad range %s\n", *argv);
			return "bad range";
		}
		min = strtoul(q, &q, 16);
		if(min<0 || min>0xFFFF || *q!='-')
			goto err;
		q++;
		if(strchr(hex, *q) == 0)
			goto err;
		max = strtoul(q, &q, 16);
		if(max<0 || max>0xFFFF || max<min || *q!=0)
			goto err;
		i = 0;
		do{
			Bprint(&bout, "%.4x %C", min, min);
			i++;
			if(min==max || (i&7)==0)
				Bprint(&bout, "\n");
			else
				Bprint(&bout, "\t");
			min++;
		}while(min<=max);
		argv++;
	}
	return 0;
}

char*
nums(char *argv[])
{
	char *q;
	Rune r;
	int w;

	while(*argv){
		q = *argv;
		while(*q){
			w = chartorune(&r, q);
			if(r==0x80 && (q[0]&0xFF)!=0x80){
				fprint(2, "unicode: invalid utf string %s\n", *argv);
				return "bad utf";
			}
			Bprint(&bout, "%.4x\n", r);
			q += w;
		}
		argv++;
	}
	return 0;
}

char*
chars(char *argv[])
{
	char *q;
	int m;

	while(*argv){
		q = *argv;
		if(strchr(hex, q[0]) == 0){
    err:
			fprint(2, "unicode: bad unicode value %s\n", *argv);
			return "bad char";
		}
		m = strtoul(q, &q, 16);
		if(m<0 || m>0xFFFF || *q!=0)
			goto err;
		Bprint(&bout, "%C", m);
		if(!text)
			Bprint(&bout, "\n");
		argv++;
	}
	return 0;
}