+irc::dynamicbitmask::dynamicbitmask() : bits_size(4)
+{
+ /* We start with 4 bytes allocated which is room
+ * for 4 items. Something makes me doubt its worth
+ * allocating less than 4 bytes.
+ */
+ bits = new unsigned char[bits_size];
+ memset(bits, 0, bits_size);
+}
+
+irc::dynamicbitmask::~dynamicbitmask()
+{
+ /* Tidy up the entire used memory on delete */
+ delete[] bits;
+}
+
+irc::bitfield irc::dynamicbitmask::Allocate()
+{
+ /* Yeah, this isnt too efficient, however a module or the core
+ * should only be allocating bitfields on load, the Toggle and
+ * Get methods are O(1) as these are called much more often.
+ */
+ unsigned char* freebits = this->GetFreeBits();
+ for (unsigned char i = 0; i < bits_size; i++)
+ {
+ /* Yes, this is right. You'll notice we terminate the loop when !current_pos,
+ * this is because we logic shift our bit off the end of unsigned char, and its
+ * lost, making the loop counter 0 when we're done.
+ */
+ for (unsigned char current_pos = 1; current_pos; current_pos = current_pos << 1)
+ {
+ if (!(freebits[i] & current_pos))
+ {
+ freebits[i] |= current_pos;
+ return std::make_pair(i, current_pos);
+ }
+ }
+ }
+ /* We dont have any free space left, increase by one */
+
+ if (bits_size == 255)
+ /* Oh dear, cant grow it any further */
+ throw std::bad_alloc();
+
+ unsigned char old_bits_size = bits_size;
+ bits_size++;
+ /* Allocate new bitfield space */
+ unsigned char* temp_bits = new unsigned char[bits_size];
+ unsigned char* temp_freebits = new unsigned char[bits_size];
+ /* Copy the old data in */
+ memcpy(temp_bits, bits, old_bits_size);
+ memcpy(temp_freebits, freebits, old_bits_size);
+ /* Delete the old data pointers */
+ delete[] bits;
+ delete[] freebits;
+ /* Swap the pointers over so now the new
+ * pointers point to our member values
+ */
+ bits = temp_bits;
+ freebits = temp_freebits;
+ this->SetFreeBits(freebits);
+ /* Initialize the new byte on the end of
+ * the bitfields, pre-allocate the one bit
+ * for this allocation
+ */
+ bits[old_bits_size] = 0;
+ freebits[old_bits_size] = 1;
+ /* We already know where we just allocated
+ * the bitfield, so no loop needed
+ */
+ return std::make_pair(old_bits_size, 1);
+}
+
+bool irc::dynamicbitmask::Deallocate(irc::bitfield &pos)
+{
+ /* We dont bother to shrink the bitfield
+ * on deallocation, the most we could do
+ * is save one byte (!) and this would cost
+ * us a loop (ugly O(n) stuff) so we just
+ * clear the bit and leave the memory
+ * claimed -- nobody will care about one
+ * byte.
+ */
+ if (pos.first < bits_size)
+ {
+ this->GetFreeBits()[pos.first] &= ~pos.second;
+ return true;
+ }
+ /* They gave a bitfield outside of the
+ * length of our array. BAD programmer.
+ */
+ return false;
+}
+
+void irc::dynamicbitmask::Toggle(irc::bitfield &pos, bool state)
+{
+ /* Range check the value */
+ if (pos.first < bits_size)
+ {
+ if (state)
+ /* Set state, OR the state in */
+ bits[pos.first] |= pos.second;
+ else
+ /* Clear state, AND the !state out */
+ bits[pos.first] &= ~pos.second;
+ }
+}
+
+bool irc::dynamicbitmask::Get(irc::bitfield &pos)
+{
+ /* Range check the value */
+ if (pos.first < bits_size)
+ return (bits[pos.first] & pos.second);
+ else
+ /* We can't return false, otherwise we can't
+ * distinguish between failure and a cleared bit!
+ * Our only sensible choice is to throw (ew).
+ */
+ throw ModuleException("irc::dynamicbitmask::Get(): Invalid bitfield, out of range");
+}
+
+unsigned char irc::dynamicbitmask::GetSize()
+{
+ return bits_size;
+}
+