// license:BSD-3-Clause // copyright-holders:Nathan Woods /*************************************************************************** fs_coco_rsdos.cpp Management of CoCo "RS-DOS" floppy images ***************************************************************************/ #include "fs_coco_rsdos.h" #include "coco_rawdsk.h" #include "util/corestr.h" #include "util/strformat.h" #include #include #include using namespace fs; namespace fs { const coco_rsdos_image COCO_RSDOS; } namespace { class coco_rsdos_impl : public filesystem_t { public: coco_rsdos_impl(fsblk_t &blockdev); virtual ~coco_rsdos_impl() = default; struct rsdos_dirent { char m_filename[11]; u8 m_filetype; u8 m_asciiflag; u8 m_first_granule; u8 m_last_sector_bytes_msb; u8 m_last_sector_bytes_lsb; }; struct rsdos_dirent_sector { struct { rsdos_dirent m_dirent; u8 m_unused[16]; } m_entries[4]; }; class granule_iterator { public: granule_iterator(coco_rsdos_impl &fs, const rsdos_dirent &dirent); bool next(u8 &granule, u16 &byte_count); private: fsblk_t::block_t m_granule_map; std::optional m_current_granule; u8 m_maximum_granules; u16 m_last_sector_bytes; std::bitset<256> m_visited_granules; }; virtual std::pair metadata(const std::vector &path) override; virtual std::pair> directory_contents(const std::vector &path) override; virtual std::pair> file_read(const std::vector &path) override; virtual err_t format(const meta_data &meta) override; static bool validate_filename(std::string_view name); private: fsblk_t::block_t read_sector(int track, int sector) const; u8 maximum_granules() const; std::optional dirent_from_path(const std::vector &path); void iterate_directory_entries(const std::function &callback); meta_data get_metadata_from_dirent(const rsdos_dirent &dirent); static std::string get_filename_from_dirent(const rsdos_dirent &dirent); }; } // anonymous namespace //------------------------------------------------- // name //------------------------------------------------- const char *coco_rsdos_image::name() const { return "coco_rsdos"; } //------------------------------------------------- // description //------------------------------------------------- const char *coco_rsdos_image::description() const { return "CoCo RS-DOS"; } //------------------------------------------------- // enumerate_f //------------------------------------------------- void coco_rsdos_image::enumerate_f(floppy_enumerator &fe) const { fe.add(FLOPPY_COCO_RAWDSK_FORMAT, floppy_image::FF_525, floppy_image::SSSD, 161280, "coco_rawdsk_rsdos_35", "CoCo Raw Disk RS-DOS single-sided 35 tracks"); fe.add(FLOPPY_COCO_RAWDSK_FORMAT, floppy_image::FF_525, floppy_image::SSSD, 184320, "coco_rawdsk_rsdos_40", "CoCo Raw Disk RS-DOS single-sided 40 tracks"); } //------------------------------------------------- // can_format //------------------------------------------------- bool coco_rsdos_image::can_format() const { return true; } //------------------------------------------------- // can_read //------------------------------------------------- bool coco_rsdos_image::can_read() const { return true; } //------------------------------------------------- // can_write //------------------------------------------------- bool coco_rsdos_image::can_write() const { return false; } //------------------------------------------------- // has_rsrc //------------------------------------------------- bool coco_rsdos_image::has_rsrc() const { return false; } //------------------------------------------------- // file_meta_description //------------------------------------------------- std::vector coco_rsdos_image::file_meta_description() const { std::vector results; results.emplace_back(meta_description(meta_name::name, "", false, [](const meta_value &m) { return coco_rsdos_impl::validate_filename(m.as_string()); }, "File name, 8.3")); results.emplace_back(meta_description(meta_name::file_type, 0, true, nullptr, "Type of the file")); results.emplace_back(meta_description(meta_name::ascii_flag, "B", true, nullptr, "Ascii or binary flag")); results.emplace_back(meta_description(meta_name::size_in_blocks, 0, true, nullptr, "Number of granules used by the file")); results.emplace_back(meta_description(meta_name::length, 0, true, nullptr, "Size of the file in bytes")); return results; } //------------------------------------------------- // mount //------------------------------------------------- std::unique_ptr coco_rsdos_image::mount(fsblk_t &blockdev) const { return std::make_unique(blockdev); } //------------------------------------------------- // validate_filename //------------------------------------------------- bool coco_rsdos_impl::validate_filename(std::string_view name) { auto pos = name.find('.'); auto stem_length = pos != std::string::npos ? pos : name.size(); auto ext_length = pos != std::string::npos ? name.size() - pos - 1 : 0; return stem_length > 0 && stem_length <= 8 && ext_length <= 3; } //------------------------------------------------- // coco_rsdos_impl ctor //------------------------------------------------- coco_rsdos_impl::coco_rsdos_impl(fsblk_t &blockdev) : filesystem_t(blockdev, 256) { } //------------------------------------------------- // coco_rsdos_impl::metadata //------------------------------------------------- std::pair coco_rsdos_impl::metadata(const std::vector &path) { // attempt to find the file const std::optional dirent = dirent_from_path(path); if (!dirent) return std::make_pair(ERR_NOT_FOUND, meta_data()); return std::make_pair(ERR_OK, get_metadata_from_dirent(*dirent)); } //------------------------------------------------- // coco_rsdos_impl::directory_contents //------------------------------------------------- std::pair> coco_rsdos_impl::directory_contents(const std::vector &path) { std::vector results; auto callback = [this, &results](const rsdos_dirent &dirent) { results.emplace_back(dir_entry_type::file, get_metadata_from_dirent(dirent)); return false; }; iterate_directory_entries(callback); return std::make_pair(ERR_OK, std::move(results)); } //------------------------------------------------- // coco_rsdos_impl::file_read //------------------------------------------------- std::pair> coco_rsdos_impl::file_read(const std::vector &path) { // attempt to find the file const std::optional dirent = dirent_from_path(path); if (!dirent) return std::make_pair(ERR_NOT_FOUND, std::vector()); std::vector result; u8 granule; u16 byte_count; granule_iterator iter(*this, *dirent); while (iter.next(granule, byte_count)) { // resize the results size_t current_size = result.size(); result.resize(current_size + byte_count); // determine which track and sector this granule starts at int track = granule / 2 + (granule >= 34 ? 1 : 0); int sector = granule % 2 * 9 + 1; // and read all the sectors while (byte_count > 0) { // read this sector auto block = read_sector(track, sector); const u8 *data = block.rodata(); u16 data_length = std::min(byte_count, u16(256)); // and append it to the results memcpy(result.data() + current_size, data, data_length); // and advance current_size += data_length; byte_count -= data_length; sector++; } } return std::make_pair(ERR_OK, std::move(result)); } //------------------------------------------------- // coco_rsdos_impl::format //------------------------------------------------- err_t coco_rsdos_impl::format(const meta_data &meta) { // formatting RS-DOS is easy - just fill everything with 0xFF m_blockdev.fill(0xFF); return ERR_OK; } //------------------------------------------------- // fsblk_t::block_t coco_rsdos_impl::read_sector //------------------------------------------------- fsblk_t::block_t coco_rsdos_impl::read_sector(int track, int sector) const { // the CoCo RS-DOS world thinks in terms of tracks/sectors, but we have a block device // abstraction return m_blockdev.get(track * 18 + sector - 1); } //------------------------------------------------- // coco_rsdos_impl::maximum_granules //------------------------------------------------- u8 coco_rsdos_impl::maximum_granules() const { u32 sector_count = m_blockdev.block_count(); u32 granule_count = (sector_count / 9) - 2; return granule_count <= 0xFF ? u8(granule_count) : 0xFF; } //------------------------------------------------- // coco_rsdos_impl::dirent_from_path //------------------------------------------------- std::optional coco_rsdos_impl::dirent_from_path(const std::vector &path) { if (path.size() != 1) return { }; const std::string &target = path[0]; std::optional result; auto callback = [&result, &target](const rsdos_dirent &dirent) { bool found = get_filename_from_dirent(dirent) == target; if (found) result = dirent; return found; }; iterate_directory_entries(callback); return result; } //------------------------------------------------- // coco_rsdos_impl::iterate_directory_entries //------------------------------------------------- void coco_rsdos_impl::iterate_directory_entries(const std::function &callback) { bool done = false; for (int dir_sector = 3; !done && dir_sector <= 18; dir_sector++) { // read this directory sector auto dir_block = read_sector(17, dir_sector); const rsdos_dirent_sector §or = *reinterpret_cast(dir_block.rodata()); // and loop through all entries for (const auto &ent : sector.m_entries) { // 0xFF marks the end of the directory if (ent.m_dirent.m_filename[0] == '\xFF') { done = true; } else { // 0x00 marks a deleted file if (ent.m_dirent.m_filename[0] != '\0') done = callback(ent.m_dirent); } if (done) break; } } } //------------------------------------------------- // coco_rsdos_impl::get_metadata_from_dirent //------------------------------------------------- meta_data coco_rsdos_impl::get_metadata_from_dirent(const rsdos_dirent &dirent) { u32 file_size = 0; int granule_count = 0; // we need to iterate on the file to determine the size and granule/block count u8 granule; u16 byte_count; granule_iterator iter(*this, dirent); while (iter.next(granule, byte_count)) { granule_count++; file_size += byte_count; } // determine the file name std::string name = get_filename_from_dirent(dirent); // turn the ASCII flag to a single character (this reflects what the user sees when doing a directory listing on a real CoCo) char file_type_char = 'B' + dirent.m_asciiflag; // build the metadata and return it meta_data result; result.set(meta_name::name, std::move(name)); result.set(meta_name::file_type, dirent.m_filetype); result.set(meta_name::ascii_flag, std::string(1, file_type_char)); result.set(meta_name::size_in_blocks, granule_count); result.set(meta_name::length, file_size); return result; } //------------------------------------------------- // coco_rsdos_impl::get_filename_from_dirent //------------------------------------------------- std::string coco_rsdos_impl::get_filename_from_dirent(const rsdos_dirent &dirent) { std::string_view stem = strtrimrightspace(std::string_view(&dirent.m_filename[0], 8)); std::string_view ext = strtrimrightspace(std::string_view(&dirent.m_filename[8], 3)); return util::string_format("%s.%s", stem, ext); } //------------------------------------------------- // coco_rsdos_impl::granule_iterator ctor //------------------------------------------------- coco_rsdos_impl::granule_iterator::granule_iterator(coco_rsdos_impl &fs, const rsdos_dirent &dirent) : m_granule_map(fs.read_sector(17, 2)) , m_current_granule(dirent.m_first_granule) , m_maximum_granules(fs.maximum_granules()) , m_last_sector_bytes((u16(dirent.m_last_sector_bytes_msb) << 8) | dirent.m_last_sector_bytes_lsb) { // visit the first granule m_visited_granules.set(dirent.m_first_granule); } //------------------------------------------------- // coco_rsdos_impl::granule_iterator::next //------------------------------------------------- bool coco_rsdos_impl::granule_iterator::next(u8 &granule, u16 &byte_count) { bool success = false; granule = ~0; byte_count = 0; if (m_current_granule) { std::optional next_granule; const u8 *granule_map_data = m_granule_map.rodata(); if (granule_map_data[*m_current_granule] < m_maximum_granules) { // this entry points to the next granule success = true; granule = *m_current_granule; byte_count = 9 * 256; next_granule = granule_map_data[*m_current_granule]; // check for cycles, which should only happen if the disk is corrupt (or not in RS-DOS format) if (m_visited_granules[*next_granule]) next_granule = std::nullopt; // this is corrupt! else m_visited_granules.set(*next_granule); } else if (granule_map_data[*m_current_granule] >= 0xC0 && granule_map_data[*m_current_granule] <= 0xC9) { // this is the last granule in the file success = true; granule = *m_current_granule; u16 sector_count = std::max(granule_map_data[*m_current_granule], u8(0xC1)) - 0xC1; byte_count = sector_count * 256 + m_last_sector_bytes; next_granule = std::nullopt; } else { // should not happen; but we'll treat this as an EOF next_granule = std::nullopt; } m_current_granule = next_granule; } return success; }