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74 lines
2.2 KiB
C++
74 lines
2.2 KiB
C++
//
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// AppleGCR.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 21/04/2018.
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// Copyright © 2018 Thomas Harte. All rights reserved.
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//
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#ifndef AppleGCR_hpp
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#define AppleGCR_hpp
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#include <cstdint>
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#include "../../Disk/Track/PCMSegment.hpp"
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namespace Storage {
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namespace Encodings {
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namespace AppleGCR {
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/*!
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@returns the eight-bit 13-sector GCR encoding for the low five bits of @c value.
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*/
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// unsigned int five_and_three_encoding_for_value(int value);
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/*!
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@returns the eight-bit 16-sector GCR encoding for the low six bits of @c value.
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*/
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// unsigned int six_and_two_encoding_for_value(int value);
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/*!
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A block is defined to be five source bytes, which encodes to eight GCR bytes.
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*/
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// void encode_five_and_three_block(uint8_t *destination, uint8_t *source);
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/*!
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A block is defined to be three source bytes, which encodes to four GCR bytes.
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*/
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// void encode_six_and_two_block(uint8_t *destination, uint8_t *source);
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/*!
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@returns the four bit nibble for the five-bit GCR @c quintet if a valid GCR value; INT_MAX otherwise.
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*/
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// unsigned int decoding_from_quintet(unsigned int quintet);
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/*!
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@returns the byte composed by splitting the dectet into two qintets, decoding each and composing the resulting nibbles.
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*/
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// unsigned int decoding_from_dectet(unsigned int dectet);
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/// Describes the standard three-byte prologue that begins a header.
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const uint8_t header_prologue[3] = {0xd5, 0xaa, 0x96};
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/// Describes the standard three-byte prologue that begins a data section.
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const uint8_t data_prologue[3] = {0xd5, 0xaa, 0xad};
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/// Describes the epilogue that ends both data sections and headers.
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const uint8_t epilogue[3] = {0xde, 0xaa, 0xeb};
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/*!
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Produces the Apple-standard '4 and 4' per-sector header. This is the same
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for both the 13- and 16-sector formats, and is 112 bits long.
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*/
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Storage::Disk::PCMSegment header(uint8_t volume, uint8_t track, uint8_t sector);
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Storage::Disk::PCMSegment six_and_two_data(const uint8_t *source);
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Storage::Disk::PCMSegment six_and_two_sync(int length);
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Storage::Disk::PCMSegment five_and_three_data(const uint8_t *source);
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Storage::Disk::PCMSegment five_and_three_sync(int length);
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}
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}
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}
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#endif /* AppleGCR_hpp */
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