108 lines
2.8 KiB
C
108 lines
2.8 KiB
C
/* read.c -- read bytes from a input device.
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*
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* Copyright (c) 1995 Cygnus Support
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*
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* The authors hereby grant permission to use, copy, modify, distribute,
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* and license this software and its documentation for any purpose, provided
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* that existing copyright notices are retained in all copies and that this
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* notice is included verbatim in any distributions. No written agreement,
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* license, or royalty fee is required for any of the authorized uses.
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* Modifications to this software may be copyrighted by their authors
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* and need not follow the licensing terms described here, provided that
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* the new terms are clearly indicated on the first page of each file where
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* they apply.
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*/
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#include <errno.h>
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#include <unistd.h>
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#include "io.h"
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#undef erro
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extern int errno;
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ssize_t read(int fd, void *buf, size_t cnt)
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{
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_ssize_t ret;
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_ssize_t read_len, total_len;
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unsigned reduce_idx, finish_idx;
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unsigned iomode_flags;
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char *buffer = buf;
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int rc;
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int h;
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unsigned amount_read;
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int err;
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__io_handle *ioh;
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if( (fd < 0) || (fd >=64) )
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{
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errno = EBADF;
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return -1;
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};
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ioh = &__io_tab[fd];
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iomode_flags = ioh->mode;
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if( iomode_flags == 0 )
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{
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errno = EBADF;
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return( -1 );
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}
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if( !(iomode_flags & _READ) )
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{
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errno = EACCES;
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return( -1 );
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}
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if( iomode_flags & _BINARY ) /* if binary mode */
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{
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err = ioh->read(ioh->name, buffer, ioh->offset, cnt, &amount_read);
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ioh->offset+= amount_read;
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total_len = amount_read;
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if(err)
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if ( amount_read == 0)
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return (-1);
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}
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else
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{
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total_len = 0;
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read_len = cnt;
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do
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{
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err=ioh->read(ioh->name,buffer, ioh->offset, cnt, &amount_read);
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ioh->offset+=amount_read;
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if( amount_read == 0 )
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break; /* EOF */
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reduce_idx = 0;
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finish_idx = reduce_idx;
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for( ; reduce_idx < amount_read; ++reduce_idx )
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{
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if( buffer[ reduce_idx ] == 0x1a ) /* EOF */
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{
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lseek(fd, ((long)reduce_idx - (long)amount_read)+1L, SEEK_CUR );
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total_len += finish_idx;
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return( total_len );
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}
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if( buffer[ reduce_idx ] != '\r' )
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{
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buffer[ finish_idx++ ] = buffer[ reduce_idx ];
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};
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}
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total_len += finish_idx;
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buffer += finish_idx;
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read_len -= finish_idx;
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if( iomode_flags & _ISTTY )
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{
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break;
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}
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} while( read_len != 0 );
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}
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return( total_len );
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}
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