Code: static float *get_window(vorb *f, int len)
{
    len <<= 1;
    if (len == f->blocksize_0) return f->window[0];
    if (len == f->blocksize_1) return f->window[1];
   assert(0);
    return NULL;
 }

Commit Message: Fix seven bugs discovered and fixed by ForAllSecure:

CVE-2019-13217: heap buffer overflow in start_decoder()
CVE-2019-13218: stack buffer overflow in compute_codewords()
CVE-2019-13219: uninitialized memory in vorbis_decode_packet_rest()
CVE-2019-13220: out-of-range read in draw_line()
CVE-2019-13221: issue with large 1D codebooks in lookup1_values()
CVE-2019-13222: unchecked NULL returned by get_window()
CVE-2019-13223: division by zero in predict_point()
CWE ID: CWE-20
static float *get_window(vorb *f, int len)
{
    len <<= 1;
    if (len == f->blocksize_0) return f->window[0];
    if (len == f->blocksize_1) return f->window[1];
    return NULL;
 }
