47 lines
975 B
C++
47 lines
975 B
C++
#include <sys/uio.h>
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#include <unistd.h>
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ssize_t readv(int fildes, const struct iovec* iov, int iovcnt)
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{
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size_t result = 0;
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for (int i = 0; i < iovcnt; i++)
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{
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uint8_t* base = static_cast<uint8_t*>(iov->iov_base);
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size_t nread = 0;
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while (nread < iov[i].iov_len)
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{
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const ssize_t ret = read(fildes, base + nread, iov[i].iov_len - nread);
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if (ret == -1 && result == 0)
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return -1;
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if (ret <= 0)
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return result;
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nread += ret;
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}
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result += nread;
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}
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return result;
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}
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ssize_t writev(int fildes, const struct iovec* iov, int iovcnt)
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{
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size_t result = 0;
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for (int i = 0; i < iovcnt; i++)
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{
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const uint8_t* base = static_cast<const uint8_t*>(iov->iov_base);
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size_t nwrite = 0;
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while (nwrite < iov[i].iov_len)
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{
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const ssize_t ret = write(fildes, base + nwrite, iov[i].iov_len - nwrite);
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if (ret == -1 && result == 0)
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return -1;
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if (ret <= 0)
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return result;
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nwrite += ret;
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}
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result += nwrite;
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}
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return result;
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}
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