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60 lines
1.5 KiB
C++
60 lines
1.5 KiB
C++
/*
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ISC License
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Copyright (c) 2023, Antonio SJ Musumeci <trapexit@spawn.link>
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#pragma once
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#include "fs_pread.hpp"
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namespace fs
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{
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static
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inline
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ssize_t
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preadn(int const fd_,
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void *buf_,
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size_t const count_,
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off_t const offset_,
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int *err_)
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{
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ssize_t rv;
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ssize_t count = count_;
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off_t offset = offset_;
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char const *buf = (char const *)buf_;
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*err_ = 0;
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while(count > 0)
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{
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rv = fs::pread(fd_,buf,count,offset);
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if(rv == 0)
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return (count_ - count);
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if(rv < 0)
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{
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*err_ = rv;
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return (count_ - count);
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}
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buf += rv;
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count -= rv;
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offset += rv;
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}
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return count_;
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}
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}
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