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88 lines
1.7 KiB
C
88 lines
1.7 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1997-2002
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* Sleepycat Software. All rights reserved.
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*/
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#include "db_config.h"
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#ifndef lint
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static const char revid[] = "$Id: os_seek.c,v 11.17 2002/08/06 04:56:20 bostic Exp $";
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#endif /* not lint */
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#include "db_int.h"
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/*
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* __os_seek --
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* Seek to a page/byte offset in the file.
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*/
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int
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__os_seek(dbenv, fhp, pgsize, pageno, relative, isrewind, db_whence)
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DB_ENV *dbenv;
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DB_FH *fhp;
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size_t pgsize;
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db_pgno_t pageno;
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u_int32_t relative;
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int isrewind;
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DB_OS_SEEK db_whence;
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{
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/* Yes, this really is how Microsoft have designed their API */
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union {
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__int64 bigint;
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struct {
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unsigned long low;
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long high;
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};
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} offset;
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int ret, whence;
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DWORD from;
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if (DB_GLOBAL(j_seek) != NULL) {
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switch (db_whence) {
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case DB_OS_SEEK_CUR:
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whence = SEEK_CUR;
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break;
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case DB_OS_SEEK_END:
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whence = SEEK_END;
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break;
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case DB_OS_SEEK_SET:
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whence = SEEK_SET;
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break;
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default:
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return (EINVAL);
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}
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ret = DB_GLOBAL(j_seek)(fhp->fd, pgsize, pageno,
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relative, isrewind, whence);
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} else {
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switch (db_whence) {
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case DB_OS_SEEK_CUR:
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from = FILE_CURRENT;
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break;
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case DB_OS_SEEK_END:
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from = FILE_END;
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break;
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case DB_OS_SEEK_SET:
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from = FILE_BEGIN;
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break;
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default:
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return (EINVAL);
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}
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offset.bigint = (__int64)pgsize * pageno + relative;
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if (isrewind)
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offset.bigint = -offset.bigint;
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ret = (SetFilePointer(fhp->handle,
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offset.low, &offset.high, from) == (DWORD) - 1) ?
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__os_win32_errno() : 0;
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}
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if (ret != 0)
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__db_err(dbenv, "seek: %lu %d %d: %s",
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(u_long)pgsize * pageno + relative,
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isrewind, db_whence, strerror(ret));
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return (ret);
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}
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