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2.2M
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void HeapBypassAllocator::unmap(void *address, bsls::Types::size_type size)
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{
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VirtualFree(address, 0, MEM_RELEASE);
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}
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} // close package namespace
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#else
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#error unsupported platform
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#endif
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namespace bdlma {
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// PRIVATE MANIPULATORS
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int HeapBypassAllocator::replenish(bsls::Types::size_type size)
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{
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// round size up to a multiple of page size
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const bsls::Types::size_type pageMask = d_pageSize - 1;
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// '%' can be very slow -- if 'd_pageSize' is a power of 2, use '&'
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const bsls::Types::size_type mod =
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!(d_pageSize & pageMask) ? (size & pageMask)
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: size % d_pageSize;
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if (0 != mod) {
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size += d_pageSize - mod;
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}
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BufferHeader *newBuffer = (BufferHeader *)(void *)map(size);
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if (0 == newBuffer) {
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return -1; // RETURN
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}
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if (d_currentBuffer_p) {
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d_currentBuffer_p->d_nextBuffer = newBuffer;
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}
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else {
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d_firstBuffer_p = newBuffer;
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}
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d_currentBuffer_p = newBuffer;
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d_endOfBuffer_p = (char *)newBuffer + size;
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newBuffer->d_nextBuffer = 0;
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newBuffer->d_size = size;
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d_cursor_p = (char *)(newBuffer + 1);
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return 0;
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}
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// CREATORS
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HeapBypassAllocator::HeapBypassAllocator()
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: d_firstBuffer_p(0)
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, d_currentBuffer_p(0)
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, d_cursor_p(0)
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, d_endOfBuffer_p(0)
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, d_alignment(bsls::AlignmentUtil::BSLS_MAX_ALIGNMENT)
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{
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#if defined(BSLS_PLATFORM_OS_UNIX)
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d_pageSize = ::sysconf(_SC_PAGESIZE);
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#else // Windows
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SYSTEM_INFO si;
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GetSystemInfo(&si);
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d_pageSize = si.dwAllocationGranularity;
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#endif
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#ifdef BSLS_PLATFORM_OS_HPUX
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// 128-bit alignment is required on HP-UX for bdesu_stacktrace,
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// 'BSLS_MAX_ALIGNMENT' at the time of this writing is only 64 bits on
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// HP-UX, which causes bus traps on alignment errors.
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struct {
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char d_dummyChar;
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__float80 d_dummyFloat80;
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} s;
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d_alignment = (char *)&s.d_dummyFloat80 - &s.d_dummyChar;
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#endif
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BSLS_ASSERT(d_alignment >= bsls::AlignmentUtil::BSLS_MAX_ALIGNMENT);
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BSLS_ASSERT(0 == (d_alignment & (d_alignment - 1))); // is power of 2
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}
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HeapBypassAllocator::~HeapBypassAllocator()
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{
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BufferHeader *buffer = d_firstBuffer_p;
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while (buffer) {
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BufferHeader *nextBuffer = buffer->d_nextBuffer;
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unmap(buffer, buffer->d_size);
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buffer = nextBuffer;
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}
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}
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// MANIPULATORS
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void *HeapBypassAllocator::allocate(bsls::Types::size_type size)
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{
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d_cursor_p = d_cursor_p + bsls::AlignmentUtil::calculateAlignmentOffset(
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d_cursor_p, static_cast<int>(d_alignment));
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if (d_endOfBuffer_p < d_cursor_p + size) {
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bsls::Types::size_type blockSize =
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size + d_alignment + sizeof(BufferHeader);
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int sts = replenish(blockSize); // 'replenish' will round up to
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// multiple of 'd_pageSize'
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