71 lines
2.7 KiB
C++
71 lines
2.7 KiB
C++
#include "icsneo/disk/diskreaddriver.h"
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#include <cstring>
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using namespace icsneo;
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using namespace icsneo::Disk;
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optional<uint64_t> ReadDriver::readLogicalDisk(Communication& com, device_eventhandler_t report,
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uint64_t pos, uint8_t* into, uint64_t amount, std::chrono::milliseconds timeout) {
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if(amount == 0)
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return 0;
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optional<uint64_t> ret;
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// Read into here if we can't read directly into the user buffer
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// That would be the case either if we don't want some at the
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// beginning or end of the block.
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std::vector<uint8_t> alignedReadBuffer;
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pos += vsaOffset;
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const uint32_t idealBlockSize = getBlockSizeBounds().second;
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const uint64_t startBlock = pos / idealBlockSize;
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const uint32_t posWithinFirstBlock = static_cast<uint32_t>(pos % idealBlockSize);
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uint64_t blocks = amount / idealBlockSize + (amount % idealBlockSize ? 1 : 0);
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if(blocks * idealBlockSize - posWithinFirstBlock < amount)
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blocks++; // We need one more block to get the last partial block's worth
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uint64_t blocksProcessed = 0;
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while(blocksProcessed < blocks && timeout >= std::chrono::milliseconds::zero()) {
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const uint64_t currentBlock = startBlock + blocksProcessed;
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uint64_t intoOffset = blocksProcessed * idealBlockSize;;
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if(intoOffset < posWithinFirstBlock)
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intoOffset = 0;
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else
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intoOffset -= posWithinFirstBlock;
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const uint32_t posWithinCurrentBlock = (blocksProcessed ? 0 : posWithinFirstBlock);
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uint32_t curAmt = idealBlockSize - posWithinCurrentBlock;
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const auto amountLeft = amount - ret.value_or(0);
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if(curAmt > amountLeft)
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curAmt = static_cast<uint32_t>(amountLeft);
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const bool useAlignedReadBuffer = (posWithinCurrentBlock != 0 || curAmt != idealBlockSize);
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if(useAlignedReadBuffer && alignedReadBuffer.size() < idealBlockSize)
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alignedReadBuffer.resize(idealBlockSize);
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auto start = std::chrono::high_resolution_clock::now();
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auto readAmount = readLogicalDiskAligned(com, report, currentBlock * idealBlockSize,
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useAlignedReadBuffer ? alignedReadBuffer.data() : (into + intoOffset), idealBlockSize, timeout);
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timeout -= std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::high_resolution_clock::now() - start);
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if(!readAmount.has_value() || *readAmount < curAmt) {
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if(timeout < std::chrono::milliseconds::zero())
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report(APIEvent::Type::Timeout, APIEvent::Severity::Error);
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else
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report((blocksProcessed || readAmount.value_or(0u) != 0u) ? APIEvent::Type::EOFReached :
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APIEvent::Type::ParameterOutOfRange, APIEvent::Severity::Error);
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break;
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}
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if(useAlignedReadBuffer)
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memcpy(into + intoOffset, alignedReadBuffer.data() + posWithinCurrentBlock, curAmt);
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if(!ret)
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ret.emplace();
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*ret += std::min<uint64_t>(*readAmount, curAmt);
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blocksProcessed++;
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}
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return ret;
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} |