Digitizer Block: Remove minor code duplication

[alexxcons]

The number of (enabled) AI/DI ports on the Digitizer on different occasions is counted by looping on all AI's / DI's. Here an example:

gr-digitizers/lib/digitizer_block_impl.cc

Lines 615 to 626 in 19061f7

	int num_enabled_ai_channels = 0;
	int num_enabled_di_ports = 0;
	for (auto i = 0; i < d_ai_channels; i++) {
	if (d_channel_settings[i].enabled) {
	num_enabled_ai_channels++;
	}
	}
	for (auto i = 0; i < d_ports; i++) {
	if (d_port_settings[i].enabled) {
	num_enabled_di_ports++;
	}
	}

Instead, provide a method which returns the number

[wirew0rm]

the counting functions already exist in the file:

gr-digitizers/lib/digitizer_block_impl.cc

Line 448 in 19061f7

digitizer_block_impl::get_enabled_aichan_count() const

gr-digitizers/lib/digitizer_block_impl.cc

Line 509 in 19061f7

digitizer_block_impl::get_enabled_diport_count() const

[RalphSteinhagen]

The number of (enabled) AI/DI ports on the Digitizer on different occasions is counted by looping on all AI's / DI's. Here an example:

gr-digitizers/lib/digitizer_block_impl.cc

Lines 615 to 626 in 19061f7

	int num_enabled_ai_channels = 0;
	int num_enabled_di_ports = 0;
	for (auto i = 0; i < d_ai_channels; i++) {
	if (d_channel_settings[i].enabled) {
	num_enabled_ai_channels++;
	}
	}
	for (auto i = 0; i < d_ports; i++) {
	if (d_port_settings[i].enabled) {
	num_enabled_di_ports++;
	}
	}

Instead, provide a method which returns the number

Your assessment is correct and std::accumulate is your friend, e.g.

auto nEnabled = std::accumulate(V.begin(), V.end(), 0, [](int a, int b){ return pred(b) ? a+b: a; });

The quoted code is pre-C++11 and C-like which we should start modernising ...