- fixed_buf = xmalloc(imgoff + extra_chars);
- memcpy(fixed_buf, img->buf + try, imgoff);
- memcpy(fixed_buf + imgoff, preimage_eof, extra_chars);
- imgoff += extra_chars;
+ strbuf_init(&fixed, imgoff + extra_chars);
+ strbuf_add(&fixed, img->buf + try, imgoff);
+ strbuf_add(&fixed, preimage_eof, extra_chars);
+ fixed_buf = strbuf_detach(&fixed, &fixed_len);