62 lines
1.2 KiB
C
62 lines
1.2 KiB
C
/* lseek for MMIXware.
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Copyright (C) 2001 Hans-Peter Nilsson.
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Permission to use, copy, modify, and distribute this software is freely
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granted, provided that this notice is preserved with no changes.
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THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE. */
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#include <_ansi.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/unistd.h>
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#include "sys/syscall.h"
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#include <errno.h>
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off_t
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_lseek (int file,
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off_t ptr,
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int dir)
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{
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off_t simoff = dir == SEEK_END ? -(ptr + 1) : ptr;
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long ret;
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if ((unsigned int) file >= 32 || _MMIX_allocated_filehandle[file] == 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 (dir == SEEK_CUR)
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{
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long curpos = TRAP2f (SYS_Ftell, file, 0);
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if (curpos == -1)
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{
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errno = EIO;
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return -1;
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}
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ptr += (off_t) curpos;
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}
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ret = TRAP2f (SYS_Fseek, file, simoff);
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if (ret == -1)
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{
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return -1;
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errno = EIO;
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}
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ret = TRAP2f (SYS_Ftell, file, 0);
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if (ret == -1)
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{
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errno = EIO;
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return -1;
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}
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return ret;
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}
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