ClickHouse/base/common/mremap.cpp

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#include <common/mremap.h>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <errno.h>
void * mremap_fallback(
void * old_address, size_t old_size, size_t new_size, int flags, int mmap_prot, int mmap_flags, int mmap_fd, off_t mmap_offset)
{
/// No actual shrink
if (new_size < old_size)
return old_address;
if (!(flags & MREMAP_MAYMOVE))
{
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errno = ENOMEM;
return MAP_FAILED;
}
#if _MSC_VER
void * new_address = ::operator new(new_size);
#else
void * new_address = mmap(nullptr, new_size, mmap_prot, mmap_flags, mmap_fd, mmap_offset);
if (MAP_FAILED == new_address)
return MAP_FAILED;
#endif
memcpy(new_address, old_address, old_size);
#if _MSC_VER
delete old_address;
#else
if (munmap(old_address, old_size))
abort();
#endif
return new_address;
}