ClickHouse/dbms/IO/ReadBufferFromMemory.cpp

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#include "ReadBufferFromMemory.h"
namespace DB
{
namespace ErrorCodes
{
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extern const int CANNOT_SEEK_THROUGH_FILE;
extern const int SEEK_POSITION_OUT_OF_BOUND;
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}
off_t ReadBufferFromMemory::seek(off_t offset, int whence)
{
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if (whence == SEEK_SET)
{
if (offset >= 0 && working_buffer.begin() + offset < working_buffer.end())
{
pos = working_buffer.begin() + offset;
return size_t(pos - working_buffer.begin());
}
else
throw Exception(
"Seek position is out of bounds. "
"Offset: "
+ std::to_string(offset) + ", Max: " + std::to_string(size_t(working_buffer.end() - working_buffer.begin())),
ErrorCodes::SEEK_POSITION_OUT_OF_BOUND);
}
else if (whence == SEEK_CUR)
{
Position new_pos = pos + offset;
if (new_pos >= working_buffer.begin() && new_pos < working_buffer.end())
{
pos = new_pos;
return size_t(pos - working_buffer.begin());
}
else
throw Exception(
"Seek position is out of bounds. "
"Offset: "
+ std::to_string(offset) + ", Max: " + std::to_string(size_t(working_buffer.end() - working_buffer.begin())),
ErrorCodes::SEEK_POSITION_OUT_OF_BOUND);
}
else
throw Exception("Only SEEK_SET and SEEK_CUR seek modes allowed.", ErrorCodes::CANNOT_SEEK_THROUGH_FILE);
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}
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off_t ReadBufferFromMemory::getPosition()
{
return pos - working_buffer.begin();
}
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}