parsing leveldb txindex

I'm trying to parse the LevelDB txindex, i.e. fetch raw transaction data given a transaction hash.

I'm reading a key-value pair from LevelDB with 't' + hash_bytes, and e.g. for transaction 444b7ecbda319e184da1a3d68968e6e0ca9346ddcf7afd0e2b887a7949128805 the key's value is

80 58 8f c4 c8 66 80 9b 24

Now, if I'm reading the bitcoin source correctly, this should be three varints:

nFile
nPos
nTxOffset

If I'm correctly decoding them, the 3 values are: 216 34694374 20004 -- which looks good. However, the data at offset 34694374 + 20004 in file 216 is unexpected:

version: 4293214589
inCount: 93952409796607

It looks like either I'm decoding the varints the wrong way or I'm calculating the file offset wrongly?

The varint read+decode code is mostly a direct port from C:

Code:

  def varint(s):
      n = 0
      while True:
          ch = read1(s)
          n = (n << 7) | (ch & 0x7f)
          if ch & 0x80:
              n += 1
          else:
              return n