49 lines
1.5 KiB
C
49 lines
1.5 KiB
C
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012, 2013, 2015.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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ioleast/readleast.c
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Reads at least as much data as requested or more.
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*******************************************************************************/
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#include <assert.h>
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#include <errno.h>
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#include <ioleast.h>
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#include <stdint.h>
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#include <unistd.h>
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size_t readleast(int fd, void* buf_ptr, size_t least, size_t max)
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{
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assert(least <= max);
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unsigned char* buf = (unsigned char*) buf_ptr;
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size_t done = 0;
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do
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{
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ssize_t amount = read(fd, buf + done, max - done);
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if ( amount < 0 )
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return done;
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if ( !amount && done < least )
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return errno = EEOF, done;
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if ( !amount )
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break;
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done += amount;
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} while ( done < least );
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return done;
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}
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