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128 lines
3.3 KiB
C++
128 lines
3.3 KiB
C++
// $Id: OS_NS_sys_uio.cpp 96519 2012-12-17 10:00:00Z johnnyw $
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#include "ace/OS_NS_sys_uio.h"
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#if !defined (ACE_HAS_INLINED_OSCALLS)
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# include "ace/OS_NS_sys_uio.inl"
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#endif /* ACE_HAS_INLINED_OSCALLS */
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#include "ace/OS_Memory.h"
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#include "ace/OS_NS_string.h"
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#include "ace/OS_NS_unistd.h"
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ACE_BEGIN_VERSIONED_NAMESPACE_DECL
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# if defined (ACE_LACKS_READV)
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// "Fake" readv for operating systems without it. Note that this is
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// thread-safe.
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ssize_t
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ACE_OS::readv_emulation (ACE_HANDLE handle,
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const iovec *iov,
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int n)
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{
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ACE_OS_TRACE ("ACE_OS::readv_emulation");
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// In case there's a single element, skip the memcpy.
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if (1 == n)
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return ACE_OS::read (handle, iov[0].iov_base, iov[0].iov_len);
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ssize_t length = 0;
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int i;
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for (i = 0; i < n; ++i)
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if (static_cast<int> (iov[i].iov_len) < 0)
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return -1;
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else
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length += iov[i].iov_len;
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char *buf;
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# if defined (ACE_HAS_ALLOCA)
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buf = (char *) alloca (length);
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# else
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ACE_NEW_RETURN (buf,
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char[length],
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-1);
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# endif /* !defined (ACE_HAS_ALLOCA) */
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length = ACE_OS::read (handle, buf, length);
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if (length != -1)
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{
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char *ptr = buf;
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ssize_t copyn = length;
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for (i = 0;
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i < n && copyn > 0;
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++i)
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{
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ACE_OS::memcpy (iov[i].iov_base, ptr,
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// iov_len is int on some platforms, size_t on others
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copyn > (int) iov[i].iov_len
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? (size_t) iov[i].iov_len
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: (size_t) copyn);
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ptr += iov[i].iov_len;
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copyn -= iov[i].iov_len;
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}
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}
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# if !defined (ACE_HAS_ALLOCA)
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delete [] buf;
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# endif /* !defined (ACE_HAS_ALLOCA) */
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return length;
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}
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# endif /* ACE_LACKS_READV */
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# if defined (ACE_LACKS_WRITEV)
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// "Fake" writev for operating systems without it. Note that this is
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// thread-safe.
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ssize_t
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ACE_OS::writev_emulation (ACE_HANDLE handle, const iovec *iov, int n)
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{
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ACE_OS_TRACE ("ACE_OS::writev_emulation");
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// To avoid having to allocate a temporary buffer to which all of
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// the data will be copied and then written, this implementation
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// performs incremental writes.
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ssize_t bytes_sent = 0;
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for (int i = 0; i < n; ++i)
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{
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ssize_t const result =
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ACE_OS::write (handle, iov[i].iov_base, iov[i].iov_len);
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if (result == -1)
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{
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// There is a subtle difference in behaviour depending on
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// whether or not any data was sent. If no data was sent,
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// then always return -1. Otherwise return bytes_sent.
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// This gives the caller an opportunity to keep track of
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// bytes that have already been sent.
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if (bytes_sent > 0)
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break;
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else
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return -1;
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}
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else
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{
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bytes_sent += result;
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// Do not continue on to the next loop iteration if the
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// amount of data sent was less than the amount data given.
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// This avoids a subtle problem where "holes" in the data
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// stream would occur if partial sends of a given buffer in
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// the iovec array occured.
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if (static_cast<size_t> (result) < iov[i].iov_len)
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break;
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}
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}
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return bytes_sent;
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}
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# endif /* ACE_LACKS_WRITEV */
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ACE_END_VERSIONED_NAMESPACE_DECL
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