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#include <IO/StdIStreamFromMemory.h>
namespace DB
{
StdIStreamFromMemory::MemoryBuf::MemoryBuf(char * begin_, size_t size_)
: begin(begin_)
, size(size_)
{
this->setg(begin, begin, begin + size);
}
StdIStreamFromMemory::MemoryBuf::int_type StdIStreamFromMemory::MemoryBuf::underflow()
{
if (gptr() < egptr())
return traits_type::to_int_type(*gptr());
return traits_type::eof();
}
StdIStreamFromMemory::MemoryBuf::pos_type
StdIStreamFromMemory::MemoryBuf::seekoff(off_type off, std::ios_base::seekdir way,
std::ios_base::openmode mode)
{
bool out_mode = (std::ios_base::out & mode) != 0;
if (out_mode)
return off_type(-1);
off_type ret(-1);
if (way == std::ios_base::beg)
ret = 0;
else if (way == std::ios_base::cur)
ret = gptr() - begin;
else if (way == std::ios_base::end)
ret = size;
if (ret == off_type(-1))
return ret;
ret += off;
if (!(ret >= 0 && size_t(ret) <= size))
return off_type(-1);
this->setg(begin, begin + ret, begin + size);
return pos_type(ret);
}
StdIStreamFromMemory::MemoryBuf::pos_type StdIStreamFromMemory::MemoryBuf::seekpos(pos_type sp,
std::ios_base::openmode mode)
{
return seekoff(off_type(sp), std::ios_base::beg, mode);
}
StdIStreamFromMemory::StdIStreamFromMemory(char * begin_, size_t size_)
: std::iostream(nullptr)
, mem_buf(begin_, size_)
{
init(&mem_buf);
}
}
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