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Switched to more conventional runtime polymorphism, also now allowing encoders (shifters as were) to be obtained, as a slightly lower-level interface than vector-of-sectors.

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This commit is contained in:
Thomas Harte 2016-11-26 13:39:20 +08:00
parent b180f04c87
commit dcfdd73077
2 changed files with 61 additions and 47 deletions
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88
Storage/Disk/Encodings/MFM.cpp
View File

@ -13,24 +13,10 @@
using namespace Storage::Encodings::MFM;
template <class T> class Shifter {
class MFMEncoder: public Encoder {
public:
virtual void add_byte(uint8_t input) = 0;
virtual void add_index_address_mark() = 0;
virtual void add_ID_address_mark() = 0;
virtual void add_data_address_mark() = 0;
virtual void add_deleted_data_address_mark() = 0;
MFMEncoder(std::vector<uint8_t> &target) : Encoder(target) {}
protected:
/*!
Intended to be overridden by subclasses; should write value out as PCM data,
MSB first.
*/
void output_short(uint16_t value);
};
template <class T> class MFMShifter: public Shifter<T> {
public:
void add_byte(uint8_t input) {
uint16_t spread_value =
(uint16_t)(
@ -45,26 +31,26 @@ template <class T> class MFMShifter: public Shifter<T> {
);
uint16_t or_bits = (uint16_t)((spread_value << 1) | (spread_value >> 1) | (output_ << 15));
output_ = spread_value | ((~or_bits) & 0xaaaa);
static_cast<T *>(this)->output_short(output_);
output_short(output_);
}
void add_index_address_mark() {
static_cast<T *>(this)->output_short(output_ = MFMIndexAddressMark);
output_short(output_ = MFMIndexAddressMark);
add_byte(MFMIndexAddressByte);
}
void add_ID_address_mark() {
static_cast<T *>(this)->output_short(output_ = MFMAddressMark);
output_short(output_ = MFMAddressMark);
add_byte(MFMIDAddressByte);
}
void add_data_address_mark() {
static_cast<T *>(this)->output_short(output_ = MFMAddressMark);
output_short(output_ = MFMAddressMark);
add_byte(MFMDataAddressByte);
}
void add_deleted_data_address_mark() {
static_cast<T *>(this)->output_short(output_ = MFMAddressMark);
output_short(output_ = MFMAddressMark);
add_byte(MFMDeletedDataAddressByte);
}
@ -72,11 +58,13 @@ template <class T> class MFMShifter: public Shifter<T> {
uint16_t output_;
};
template <class T> class FMShifter: public Shifter<T> {
class FMEncoder: public Encoder {
// encodes each 16-bit part as clock, data, clock, data [...]
public:
FMEncoder(std::vector<uint8_t> &target) : Encoder(target) {}
void add_byte(uint8_t input) {
static_cast<T *>(this)->output_short(
output_short(
(uint16_t)(
((input & 0x01) << 0) |
((input & 0x02) << 1) |
@ -90,10 +78,10 @@ template <class T> class FMShifter: public Shifter<T> {
));
}
void add_index_address_mark() { static_cast<T *>(this)->output_short(FMIndexAddressMark); }
void add_ID_address_mark() { static_cast<T *>(this)->output_short(FMIDAddressMark); }
void add_data_address_mark() { static_cast<T *>(this)->output_short(FMDataAddressMark); }
void add_deleted_data_address_mark() { static_cast<T *>(this)->output_short(FMDeletedDataAddressMark); }
void add_index_address_mark() { output_short(FMIndexAddressMark); }
void add_ID_address_mark() { output_short(FMIDAddressMark); }
void add_data_address_mark() { output_short(FMDataAddressMark); }
void add_deleted_data_address_mark() { output_short(FMDeletedDataAddressMark); }
};
static uint8_t logarithmic_size_for_size(size_t size)
@ -118,7 +106,9 @@ template<class T> std::shared_ptr<Storage::Disk::Track>
size_t inter_sector_gap,
size_t expected_track_bytes)
{
T shifter;
Storage::Disk::PCMSegment segment;
segment.data.reserve(expected_track_bytes);
T shifter(segment.data);
NumberTheory::CRC16 crc_generator(0x1021, 0xffff);
// output the index mark
@ -174,26 +164,25 @@ template<class T> std::shared_ptr<Storage::Disk::Track>
for(int c = 0; c < inter_sector_gap; c++) shifter.add_byte(0x4e);
}
while(shifter.segment.data.size() < expected_track_bytes) shifter.add_byte(0x00);
while(segment.data.size() < expected_track_bytes) shifter.add_byte(0x00);
shifter.segment.number_of_bits = (unsigned int)(shifter.segment.data.size() * 8);
return std::shared_ptr<Storage::Disk::Track>(new Storage::Disk::PCMTrack(std::move(shifter.segment)));
segment.number_of_bits = (unsigned int)(segment.data.size() * 8);
return std::shared_ptr<Storage::Disk::Track>(new Storage::Disk::PCMTrack(std::move(segment)));
}
struct VectorReceiver {
void output_short(uint16_t value) {
segment.data.push_back(value >> 8);
segment.data.push_back(value & 0xff);
}
Storage::Disk::PCMSegment segment;
};
Encoder::Encoder(std::vector<uint8_t> &target) :
target_(target)
{}
void Encoder::output_short(uint16_t value)
{
target_.push_back(value >> 8);
target_.push_back(value & 0xff);
}
std::shared_ptr<Storage::Disk::Track> Storage::Encodings::MFM::GetFMTrackWithSectors(const std::vector<Sector> &sectors)
{
struct VectorShifter: public FMShifter<VectorShifter>, VectorReceiver {
using VectorReceiver::output_short;
};
return GetTrackWithSectors<VectorShifter>(
return GetTrackWithSectors<FMEncoder>(
sectors,
16, 0x00,
6, 0,
@ -204,10 +193,7 @@ std::shared_ptr<Storage::Disk::Track> Storage::Encodings::MFM::GetFMTrackWithSec
std::shared_ptr<Storage::Disk::Track> Storage::Encodings::MFM::GetMFMTrackWithSectors(const std::vector<Sector> &sectors)
{
struct VectorShifter: public MFMShifter<VectorShifter>, VectorReceiver {
using VectorReceiver::output_short;
};
return GetTrackWithSectors<VectorShifter>(
return GetTrackWithSectors<MFMEncoder>(
sectors,
50, 0x4e,
12, 22,
@ -215,3 +201,13 @@ std::shared_ptr<Storage::Disk::Track> Storage::Encodings::MFM::GetMFMTrackWithSe
32,
12500); // unintelligently: double the single-density bytes/rotation (or: 500kps @ 300 rpm)
}
std::unique_ptr<Encoder> Storage::Encodings::MFM::GetMFMEncoder(std::vector<uint8_t> &target)
{
return std::unique_ptr<Encoder>(new MFMEncoder(target));
}
std::unique_ptr<Encoder> Storage::Encodings::MFM::GetFMEncoder(std::vector<uint8_t> &target)
{
return std::unique_ptr<Encoder>(new FMEncoder(target));
}

20
Storage/Disk/Encodings/MFM.hpp
View File

@ -29,7 +29,6 @@ const uint8_t MFMIDAddressByte = 0xfe;
const uint8_t MFMDataAddressByte = 0xfb;
const uint8_t MFMDeletedDataAddressByte = 0xf8;
struct Sector {
uint8_t track, side, sector;
std::vector<uint8_t> data;
@ -38,6 +37,25 @@ struct Sector {
std::shared_ptr<Storage::Disk::Track> GetMFMTrackWithSectors(const std::vector<Sector> &sectors);
std::shared_ptr<Storage::Disk::Track> GetFMTrackWithSectors(const std::vector<Sector> &sectors);
class Encoder {
public:
Encoder(std::vector<uint8_t> &target);
virtual void add_byte(uint8_t input) = 0;
virtual void add_index_address_mark() = 0;
virtual void add_ID_address_mark() = 0;
virtual void add_data_address_mark() = 0;
virtual void add_deleted_data_address_mark() = 0;
protected:
void output_short(uint16_t value);
private:
std::vector<uint8_t> &target_;
};
std::unique_ptr<Encoder> GetMFMEncoder(std::vector<uint8_t> &target);
std::unique_ptr<Encoder> GetFMEncoder(std::vector<uint8_t> &target);
}
}
}