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49 lines
1.5 KiB
C++
49 lines
1.5 KiB
C++
#include <DB/IO/copyData.h>
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namespace DB
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{
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static void copyDataImpl(ReadBuffer & from, WriteBuffer & to, bool check_bytes, size_t bytes, std::atomic<bool> * is_cancelled)
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{
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/// Если дочитали до конца буфера, eof() либо заполнит буфер новыми данными и переместит курсор в начало, либо вернёт false.
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while (bytes > 0 && !from.eof())
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{
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if (is_cancelled && *is_cancelled)
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return;
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/// buffer() - кусок данных, доступных для чтения; position() - курсор места, до которого уже дочитали.
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size_t count = std::min(bytes, static_cast<size_t>(from.buffer().end() - from.position()));
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to.write(from.position(), count);
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from.position() += count;
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bytes -= count;
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}
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if (check_bytes && bytes > 0)
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throw Exception("Attempt to read after EOF.", ErrorCodes::ATTEMPT_TO_READ_AFTER_EOF);
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}
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void copyData(ReadBuffer & from, WriteBuffer & to)
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{
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copyDataImpl(from, to, false, std::numeric_limits<size_t>::max(), nullptr);
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}
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void copyData(ReadBuffer & from, WriteBuffer & to, std::atomic<bool> & is_cancelled)
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{
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copyDataImpl(from, to, false, std::numeric_limits<size_t>::max(), &is_cancelled);
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}
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void copyData(ReadBuffer & from, WriteBuffer & to, size_t bytes)
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{
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copyDataImpl(from, to, true, bytes, nullptr);
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}
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void copyData(ReadBuffer & from, WriteBuffer & to, size_t bytes, std::atomic<bool> & is_cancelled)
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{
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copyDataImpl(from, to, true, bytes, &is_cancelled);
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}
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}
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