void write_var(std::fstream &stream, T variable)
{
static_assert(std::is_signed<T>::value == false, "Value must be unsigned");
constexpr const BYTE ZERO_BITTED = std::numeric_limits<BYTE>::max() / 2;
constexpr const BYTE ONE_BITTED = ZERO_BITTED + 1;
loop:
{
if ((variable & ~ZERO_BITTED) == 0)
{
stream.put(static_cast<BYTE>(variable));
return;
}
else
{
stream.put(static_cast<BYTE>((variable & ZERO_BITTED) | ONE_BITTED));
variable >>= 7;
}
}
goto loop;
}
uint64_t erase (const size_t offset, std::fstream &lib)
{
// ar header format:
// offset, length, description
// 0 16 File name, ASCII
// 16 12 File modification timestamp, Decimal
// 28 6 Owner ID, Decimal
// 34 6 Group ID, Decimal
// 40 8 File mode, Octal
// 48 10 File size in bytes, Decimal
// 58 2 File magic, 0x60 0x0A
// we will use this a lot. this are right-padded.
const char zero = 0x30;
const char pad = 0x20;
// first of all, archive creation timestamp goes to zero
lib.seekp (static_cast<int64_t> (offset + 16));
lib.put (zero);
for (size_t i = 0; i < 11; ++i)
lib.put (pad);
// now the uid:
lib.seekp (static_cast<int64_t> (offset + 28));
lib.put (zero);
for (size_t i = 0; i < 5; ++i)
lib.put (pad);
// and gid
lib.seekp (static_cast<int64_t> (offset + 34));
lib.put (zero);
for (size_t i = 0; i < 5; ++i)
lib.put (pad);
// return the size:
lib.seekg (static_cast<int64_t> (offset + 48));
char size[10];
lib.read (size, 10);
for (ssize_t i = 9; i >= 0; --i) {
if (size[i] == pad)
size[i] = '\0';
}
uint64_t ret = static_cast<uint64_t> (std::atol (size));
if (ret % 2 != 0)
++ret; // everything is aligned to uint16_t, but file size is the
// actual file size.
ret += 60; // add header size
return ret;
}