httpunesc.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 <bin.h>
#include <httpd.h>

/*
 *  go from http with latin1 escapes to utf,
 *  we assume that anything >= Runeself is already in utf
 */
char *
httpunesc(HConnect *cc, char *s)
{
	char *t, *v;
	int c;
	Htmlesc *e;

	v = halloc(cc, UTFmax*strlen(s) + 1);
	for(t = v; c = *s;){
		if(c == '&'){
			if(s[1] == '#' && s[2] && s[3] && s[4] && s[5] == ';'){
				c = atoi(s+2);
				if(c < Runeself){
					*t++ = c;
					s += 6;
					continue;
				}
				if(c < 256 && c >= 161){
					e = &htmlesc[c-161];
					t += runetochar(t, &e->value);
					s += 6;
					continue;
				}
			} else {
				for(e = htmlesc; e->name != nil; e++)
					if(strncmp(e->name, s, strlen(e->name)) == 0)
						break;
				if(e->name != nil){
					t += runetochar(t, &e->value);
					s += strlen(e->name);
					continue;
				}
			}
		}
		*t++ = c;
		s++;
	}
	*t = 0;
	return v;
}