text: #include "stdio_impl.h"
  #include <string.h>
  
  size_t __string_read(FILE *f, unsigned char *buf, size_t len)
  {
  	char *src = f->cookie;
  	size_t k = len+256;
  	char *end = memchr(src, 0, k);
  	if (end) k = end-src;
  	if (k < len) len = k;
  	memcpy(buf, src, len);
  	f->rpos = (void *)(src+len);
  	f->rend = (void *)(src+k);
  	f->cookie = src+k;
  	return len;
  }
  