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// 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 true;
}
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;
}
void coco_rsdos_image::impl::format(const meta_data &meta)
{
// formatting RS-DOS is easy - just fill everything with 0xFF
m_blockdev.fill(0xFF);
}
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
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