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/******************************************************************************
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* *
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* License Agreement *
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* *
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* Copyright (c) 2004-2005 Altera Corporation, San Jose, California, USA. *
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* All rights reserved. *
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* *
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* Permission is hereby granted, free of charge, to any person obtaining a *
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* copy of this software and associated documentation files (the "Software"), *
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* to deal in the Software without restriction, including without limitation *
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* the rights to use, copy, modify, merge, publish, distribute, sublicense, *
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* and/or sell copies of the Software, and to permit persons to whom the *
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* Software is furnished to do so, subject to the following conditions: *
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* *
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* The above copyright notice and this permission notice shall be included in *
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* all copies or substantial portions of the Software. *
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* *
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER *
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* DEALINGS IN THE SOFTWARE. *
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* *
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* This agreement shall be governed in all respects by the laws of the State *
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* of California and by the laws of the United States of America. *
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* *
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* Altera does not recommend, suggest or require that this reference design *
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* file be used in conjunction or combination with any other product. *
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******************************************************************************/
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#include <unistd.h>
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#include "sys/alt_errno.h"
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#include "sys/alt_warning.h"
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#include "priv/alt_file.h"
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#include "os/alt_syscall.h"
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#ifdef ALT_USE_DIRECT_DRIVERS
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off_t ALT_LSEEK (int file, off_t ptr, int dir)
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{
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/* Generate a link time warning, should this function ever be called. */
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ALT_STUB_WARNING(lseek);
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/* Indicate an error */
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ALT_ERRNO = ENOSYS;
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return -1;
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}
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#else /* !ALT_USE_DIRECT_DRIVERS */
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/*
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* lseek() can be called to move the read/write pointer associated with the
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* file descriptor "file". This function simply vectors the call to the lseek()
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* function provided by the driver associated with the file descriptor.
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*
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* If the driver does not provide an implementation of lseek() an error is
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* indicated.
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*
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* lseek() corresponds to the standard lseek() function.
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*
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* ALT_LSEEK is mapped onto the lseek() system call in alt_syscall.h
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*
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*/
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off_t ALT_LSEEK (int file, off_t ptr, int dir)
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{
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alt_fd* fd;
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off_t rc = 0;
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/*
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* A common error case is that when the file descriptor was created, the call
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* to open() failed resulting in a negative file descriptor. This is trapped
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* below so that we don't try and process an invalid file descriptor.
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*/
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fd = (file < 0) ? NULL : &alt_fd_list[file];
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if (fd)
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{
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/*
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* If the device driver provides an implementation of the lseek() function,
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* then call that to process the request.
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*/
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if (fd->dev->lseek)
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{
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rc = fd->dev->lseek(fd, ptr, dir);
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}
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/*
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* Otherwise return an error.
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*/
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else
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{
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rc = -ENOTSUP;
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}
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}
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else
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{
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rc = -EBADFD;
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}
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if (rc < 0)
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{
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ALT_ERRNO = -rc;
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rc = -1;
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}
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return rc;
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}
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#endif /* ALT_USE_DIRECT_DRIVERS */
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