php addslashes函数

php addslashes函数最终对应的c函数为：

3244 PHPAPI char *php_addslashes_ex(char *str, int length, int *new_length, int should_free, int ignore_sybase TS RMLS_DC)

3245 {

3246 /* maximum string length, worst case situation */

3247 char *new_str;

3248 char *source, *target;

3249 char *end;

3250 int local_new_length;

3251

3252 if (!new_length) {

3253 new_length = &local_new_length;

3254 }

3255 if (!str) {

3256 *new_length = 0;

3257 return str;

3258 }

3259 new_str = (char *) safe_emalloc(2, (length ? length : (length = strlen(str))), 1);

3260 source = str;

3261 end = source + length;

3262 target = new_str;

3263

3264 if (!ignore_sybase && PG(magic_quotes_sybase)) {

3265 while (source

3266 switch (*source) {

3267 case '\0':

3268 *target++ = '\\';

3269 *target++ = '0';

3270 break;

3271 case '\'':

3272 *target++ = '\'';

3273 *target++ = '\'';

3274 break;

3275 default:

3276 *target++ = *source;

3277 break;

3278 }

3279 source++;

3280 }

3281 } else {

3282 while (source

3283 switch (*source) {

3284 case '\0':

3285 *target++ = '\\';

3286 *target++ = '0';

3287 break;

3288 case '\'':

3289 case '\"':

3290 case '\\':

3291 *target++ = '\\';

3292 /* break is missing *intentionally* */

3293 default:

3294 *target++ = *source;

3295 break;

3296 }

3297

3298 source++;

3299 }

3300 }

3301

3302 *target = 0;

3303 *new_length = target - new_str;

3304 if (should_free) {

3305 STR_FREE(str);

3306 }

3307 new_str = (char *) erealloc(new_str, *new_length + 1);

3308 return new_str;

3309 }

从上面看addslashes函数处理的是单字节的字节。

但是gbk编码是双字节的。而且5c又可以做双字节的低位。