Fix off-by-one type bug!

Ugh!

Also, we'll use memcpy instead of our reckless uint64_t
reinterpret_cast, it feels more correct this way (and the compiler
should see through it anyhow)

src/lib/bit_file/bitmatrix.h

@@ -18,25 +18,31 @@ class bitmatrix
  while (size >= 8)
  {
  // we're turning 1 uint64_t into 8 uint8_ts
- const uint64_t* hax = reinterpret_cast<const uint64_t*>(p);
- uint64_t mval = (*hax) & 0x101010101010101ULL;
+ uint64_t mval;
+ memcpy(&mval, p, sizeof mval);
+ mval = mval & 0x101010101010101ULL;
  const uint8_t* cv = reinterpret_cast<const uint8_t*>(&mval);
  // TODO: what about endianness???
- uint8_t val = cv[0] << 7 | cv[1] << 6 | cv[2] << 5 | cv[3] << 4 | cv[4] << 3 | cv[5] << 2 | cv[6] << 1 | cv[7];
+ uint8_t val = (
+ cv[0] << 7 | cv[1] << 6 | cv[2] << 5 | cv[3] << 4 | cv[4] << 3 | cv[5] << 2 |
+ cv[6] << 1 | cv[7]
+ );
  writer << val;
  p += 8;
  size -= 8;
  }
 
  // remainder
- uint8_t val = 0;
- while (size > 0)
+ if (size > 0)
  {
- val |= (*p > 0) << size;
- ++p;
- --size;
+ uint8_t val = 0;
+ while (size > 0) {
+ val |= (*p > 0) << size;
+ ++p;
+ --size;
+ }
+ writer << val;
  }
- writer << val;
  }
 
 public: