From dcfdd73077325eae067eab2f1a3882d8ce1a3e2c Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sat, 26 Nov 2016 13:39:20 +0800
Subject: [PATCH] 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.
---
Storage/Disk/Encodings/MFM.cpp | 88 ++++++++++++++++------------------
Storage/Disk/Encodings/MFM.hpp | 20 +++++++-
2 files changed, 61 insertions(+), 47 deletions(-)
diff --git a/Storage/Disk/Encodings/MFM.cpp b/Storage/Disk/Encodings/MFM.cpp
index 949588528..8c864ff53 100644
--- a/Storage/Disk/Encodings/MFM.cpp
+++ b/Storage/Disk/Encodings/MFM.cpp
@@ -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> §ors)
{
- 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> §ors)
{
- 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));
+}
diff --git a/Storage/Disk/Encodings/MFM.hpp b/Storage/Disk/Encodings/MFM.hpp
index affb2fb78..57e4b11da 100644
--- a/Storage/Disk/Encodings/MFM.hpp
+++ b/Storage/Disk/Encodings/MFM.hpp
@@ -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> §ors);
std::shared_ptr<Storage::Disk::Track> GetFMTrackWithSectors(const std::vector<Sector> §ors);
+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);
+
}
}
}