Add some CP/M smarts to +3 disk analysis.

Storage/Disk/Encodings/MFM/Parser.cpp

@@ -71,3 +71,15 @@ const Sector *Parser::sector(int head, int track, uint8_t sector) {
 
 	return &stored_sector->second;
 }
+
+const Sector *Parser::any_sector(int head, int track) {
+	const Disk::Track::Address address(head, Storage::Disk::HeadPosition(track));
+	install_track(address);
+
+	const auto sectors = sectors_by_address_by_track_.find(address);
+	if(sectors == sectors_by_address_by_track_.end()) {
+		return nullptr;
+	}
+
+	return &sectors->second.begin()->second;
+}

Storage/Disk/Encodings/MFM/Parser.hpp

@@ -37,6 +37,14 @@ class Parser {
 		*/
 		const Storage::Encodings::MFM::Sector *sector(int head, int track, uint8_t sector);
 
+
+		/*!
+			Seeks to the physical track at @c head and @c track. Searches on it for any sector.
+
+			@returns a sector if one was found; @c nullptr otherwise.
+		*/
+		const Storage::Encodings::MFM::Sector *any_sector(int head, int track);
+
 		// TODO: set_sector.
 
 	private:

Storage/Disk/Parsers/CPM.hpp

@@ -24,6 +24,29 @@ struct ParameterBlock {
 	int first_sector;
 	uint16_t catalogue_allocation_bitmap;
 	int reserved_tracks;
+
+	// Some well-known formats.
+	static ParameterBlock cpc_data_format() {
+		Storage::Disk::CPM::ParameterBlock data_format;
+		data_format.sectors_per_track = 9;
+		data_format.tracks = 40;
+		data_format.block_size = 1024;
+		data_format.first_sector = 0xc1;
+		data_format.catalogue_allocation_bitmap = 0xc000;
+		data_format.reserved_tracks = 0;
+		return data_format;
+	}
+
+	static ParameterBlock cpc_system_format() {
+		Storage::Disk::CPM::ParameterBlock system_format;
+		system_format.sectors_per_track = 9;
+		system_format.tracks = 40;
+		system_format.block_size = 1024;
+		system_format.first_sector = 0x41;
+		system_format.catalogue_allocation_bitmap = 0xc000;
+		system_format.reserved_tracks = 2;
+		return system_format;
+	}
 };
 
 struct File {