diff options
author | 2022-01-03 03:47:01 -0500 | |
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committer | 2022-01-03 09:47:01 +0100 | |
commit | fbff8a2483f0fd6eea53995fdf189817f81435d8 (patch) | |
tree | 7e2a641d018198bdcebd332b070bb74cf5f65cd2 /src/lib/formats/fs_coco_rsdos.cpp | |
parent | 53d6b930ef0b871aa041040fce22ee09bb74678d (diff) |
Reimplemented support for the CoCo's RS-DOS filesystem on top of the "fsmgr" framework (currently read only) (#9080)
* Reimplemented support for the CoCo's RS-DOS filesystem on top of the "fsmgr" framework (currently read only)
* Added support for file_type and ascii_flag metadata, minor bug fix decoding file allocation table entries
* Creating a "CoCo Raw Disk" format and changing the CoCo RS-DOS filesystem to use it
* 1. Adding COCO_RAWDSK to all.cpp
2. Fixing sector order on CoCo raw disk
Diffstat (limited to 'src/lib/formats/fs_coco_rsdos.cpp')
-rw-r--r-- | src/lib/formats/fs_coco_rsdos.cpp | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/src/lib/formats/fs_coco_rsdos.cpp b/src/lib/formats/fs_coco_rsdos.cpp new file mode 100644 index 00000000000..99c36bb97e6 --- /dev/null +++ b/src/lib/formats/fs_coco_rsdos.cpp @@ -0,0 +1,297 @@ +// 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 <optional> +#include <string_view> + +namespace fs { + +const coco_rsdos_image COCO_RSDOS; + +const char *coco_rsdos_image::name() const +{ + return "coco_rsdos"; +} + +const char *coco_rsdos_image::description() const +{ + return "CoCo RS-DOS"; +} + +void coco_rsdos_image::enumerate_f(floppy_enumerator &fe, u32 form_factor, const std::vector<u32> &variants) const +{ + if (has(form_factor, variants, floppy_image::FF_525, floppy_image::SSDD)) + { + fe.add(FLOPPY_COCO_RAWDSK_FORMAT, 161280, "coco_rawdsk_rsdos_35", "CoCo Raw Disk RS-DOS single-sided 35 tracks"); + fe.add(FLOPPY_COCO_RAWDSK_FORMAT, 184320, "coco_rawdsk_rsdos_40", "CoCo Raw Disk RS-DOS single-sided 40 tracks"); + } +} + +bool coco_rsdos_image::can_format() const +{ + return false; +} + +bool coco_rsdos_image::can_read() const +{ + return true; +} + +bool coco_rsdos_image::can_write() const +{ + return false; +} + +bool coco_rsdos_image::has_rsrc() const +{ + return false; +} + +std::vector<meta_description> coco_rsdos_image::file_meta_description() const +{ + std::vector<meta_description> results; + results.emplace_back(meta_description(meta_name::name, meta_type::string, "", false, [](const meta_value &m) { return validate_filename(m.as_string()); }, "File name, 8.3")); + results.emplace_back(meta_description(meta_name::file_type, meta_type::number, 0, true, nullptr, "Type of the file")); + results.emplace_back(meta_description(meta_name::ascii_flag, meta_type::string, 0, true, nullptr, "Ascii or binary flag")); + results.emplace_back(meta_description(meta_name::size_in_blocks, meta_type::number, 0, true, nullptr, "Number of granules used by the file")); + results.emplace_back(meta_description(meta_name::length, meta_type::number, 0, true, nullptr, "Size of the file in bytes")); + return results; +} + +std::unique_ptr<filesystem_t> coco_rsdos_image::mount(fsblk_t &blockdev) const +{ + return std::make_unique<impl>(blockdev); +} + +bool coco_rsdos_image::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_image::impl::impl(fsblk_t &blockdev) + : filesystem_t(blockdev, 256) +{ +} + +meta_data coco_rsdos_image::impl::metadata() +{ + return meta_data(); +} + +filesystem_t::dir_t coco_rsdos_image::impl::root() +{ + if (!m_root) + m_root = new root_dir(*this); + return m_root.strong(); +} + +void coco_rsdos_image::impl::drop_root_ref() +{ + m_root = nullptr; +} + +fsblk_t::block_t coco_rsdos_image::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); +} + +u8 coco_rsdos_image::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; +} + +std::string coco_rsdos_image::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); +} + +void coco_rsdos_image::impl::root_dir::drop_weak_references() +{ + m_fs.drop_root_ref(); +} + +meta_data coco_rsdos_image::impl::root_dir::metadata() +{ + return meta_data(); +} + +std::vector<dir_entry> coco_rsdos_image::impl::root_dir::contents() +{ + u64 key = 0; + std::vector<dir_entry> results; + for (int dir_sector = 3; dir_sector <= 18; dir_sector++) + { + // read this directory sector + auto dir_block = m_fs.read_sector(17, dir_sector); + const rsdos_dirent_sector §or = *reinterpret_cast<const rsdos_dirent_sector *>(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') + return results; + + // 0x00 marks a deleted file + if (ent.m_dirent.m_filename[0] != '\0') + results.emplace_back(get_filename_from_dirent(ent.m_dirent), dir_entry_type::file, key); + + key++; + } + } + return results; +} + +filesystem_t::file_t coco_rsdos_image::impl::root_dir::file_get(u64 key) +{ + auto dir_block = m_fs.read_sector(17, 3 + key / 4); + const rsdos_dirent_sector §or = *reinterpret_cast<const rsdos_dirent_sector *>(dir_block.rodata()); + const rsdos_dirent &ent = sector.m_entries[key % 4].m_dirent; + return file_t(new file(m_fs, rsdos_dirent(ent))); +} + +filesystem_t::dir_t coco_rsdos_image::impl::root_dir::dir_get(u64 key) +{ + throw std::logic_error("Directories not supported"); +} + +coco_rsdos_image::impl::granule_iterator::granule_iterator(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) +{ +} + +bool coco_rsdos_image::impl::granule_iterator::next(u8 &granule, u16 &byte_count) +{ + bool success = false; + granule = ~0; + byte_count = 0; + + if (m_current_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; + m_current_granule = granule_map_data[*m_current_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; + m_current_granule = std::nullopt; + } + else + { + // should not happen; but we'll treat this as an EOF + m_current_granule = std::nullopt; + } + } + return success; +} + +coco_rsdos_image::impl::file::file(impl &fs, rsdos_dirent &&dirent) + : m_fs(fs) + , m_dirent(std::move(dirent)) +{ +} + +void coco_rsdos_image::impl::file::drop_weak_references() +{ +} + +meta_data coco_rsdos_image::impl::file::metadata() +{ + 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(m_fs, m_dirent); + while (iter.next(granule, byte_count)) + { + granule_count++; + file_size += byte_count; + } + + // 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' + m_dirent.m_asciiflag; + + // build the metadata and return it + meta_data result; + result.set(meta_name::name, get_filename_from_dirent(m_dirent)); + result.set(meta_name::file_type, m_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; +} + +std::vector<u8> coco_rsdos_image::impl::file::read_all() +{ + std::vector<u8> result; + + u8 granule; + u16 byte_count; + granule_iterator iter(m_fs, m_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 = m_fs.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 result; +} + +} // namespace fs |