Imported Upstream version 2.0.3

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+/*
+** 2001 September 16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This header file (together with is companion C source-code file
+** "os.c") attempt to abstract the underlying operating system so that
+** the SQLite library will work on both POSIX and windows systems.
+**
+** This header file is #include-ed by sqliteInt.h and thus ends up
+** being included by every source file.
+*/
+#ifndef _SQLITE_OS_H_
+#define _SQLITE_OS_H_
+
+/*
+** Figure out if we are dealing with Unix, Windows, or some other
+** operating system.  After the following block of preprocess macros,
+** all of SQLITE_OS_UNIX, SQLITE_OS_WIN, SQLITE_OS_OS2, and SQLITE_OS_OTHER 
+** will defined to either 1 or 0.  One of the four will be 1.  The other 
+** three will be 0.
+*/
+#if defined(SQLITE_OS_OTHER)
+# if SQLITE_OS_OTHER==1
+#   undef SQLITE_OS_UNIX
+#   define SQLITE_OS_UNIX 0
+#   undef SQLITE_OS_WIN
+#   define SQLITE_OS_WIN 0
+#   undef SQLITE_OS_OS2
+#   define SQLITE_OS_OS2 0
+# else
+#   undef SQLITE_OS_OTHER
+# endif
+#endif
+#if !defined(SQLITE_OS_UNIX) && !defined(SQLITE_OS_OTHER)
+# define SQLITE_OS_OTHER 0
+# ifndef SQLITE_OS_WIN
+#   if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__)
+#     define SQLITE_OS_WIN 1
+#     define SQLITE_OS_UNIX 0
+#     define SQLITE_OS_OS2 0
+#   elif defined(__EMX__) || defined(_OS2) || defined(OS2) || defined(_OS2_) || defined(__OS2__)
+#     define SQLITE_OS_WIN 0
+#     define SQLITE_OS_UNIX 0
+#     define SQLITE_OS_OS2 1
+#   else
+#     define SQLITE_OS_WIN 0
+#     define SQLITE_OS_UNIX 1
+#     define SQLITE_OS_OS2 0
+#  endif
+# else
+#  define SQLITE_OS_UNIX 0
+#  define SQLITE_OS_OS2 0
+# endif
+#else
+# ifndef SQLITE_OS_WIN
+#  define SQLITE_OS_WIN 0
+# endif
+#endif
+
+/*
+** Determine if we are dealing with WindowsCE - which has a much
+** reduced API.
+*/
+#if defined(_WIN32_WCE)
+# define SQLITE_OS_WINCE 1
+#else
+# define SQLITE_OS_WINCE 0
+#endif
+
+
+/*
+** Define the maximum size of a temporary filename
+*/
+#if SQLITE_OS_WIN
+# include <windows.h>
+# define SQLITE_TEMPNAME_SIZE (MAX_PATH+50)
+#elif SQLITE_OS_OS2
+# if (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3) && defined(OS2_HIGH_MEMORY)
+#  include <os2safe.h> /* has to be included before os2.h for linking to work */
+# endif
+# define INCL_DOSDATETIME
+# define INCL_DOSFILEMGR
+# define INCL_DOSERRORS
+# define INCL_DOSMISC
+# define INCL_DOSPROCESS
+# define INCL_DOSMODULEMGR
+# define INCL_DOSSEMAPHORES
+# include <os2.h>
+# include <uconv.h>
+# define SQLITE_TEMPNAME_SIZE (CCHMAXPATHCOMP)
+#else
+# define SQLITE_TEMPNAME_SIZE 200
+#endif
+
+/* If the SET_FULLSYNC macro is not defined above, then make it
+** a no-op
+*/
+#ifndef SET_FULLSYNC
+# define SET_FULLSYNC(x,y)
+#endif
+
+/*
+** The default size of a disk sector
+*/
+#ifndef SQLITE_DEFAULT_SECTOR_SIZE
+# define SQLITE_DEFAULT_SECTOR_SIZE 512
+#endif
+
+/*
+** Temporary files are named starting with this prefix followed by 16 random
+** alphanumeric characters, and no file extension. They are stored in the
+** OS's standard temporary file directory, and are deleted prior to exit.
+** If sqlite is being embedded in another program, you may wish to change the
+** prefix to reflect your program's name, so that if your program exits
+** prematurely, old temporary files can be easily identified. This can be done
+** using -DSQLITE_TEMP_FILE_PREFIX=myprefix_ on the compiler command line.
+**
+** 2006-10-31:  The default prefix used to be "sqlite_".  But then
+** Mcafee started using SQLite in their anti-virus product and it
+** started putting files with the "sqlite" name in the c:/temp folder.
+** This annoyed many windows users.  Those users would then do a 
+** Google search for "sqlite", find the telephone numbers of the
+** developers and call to wake them up at night and complain.
+** For this reason, the default name prefix is changed to be "sqlite" 
+** spelled backwards.  So the temp files are still identified, but
+** anybody smart enough to figure out the code is also likely smart
+** enough to know that calling the developer will not help get rid
+** of the file.
+*/
+#ifndef SQLITE_TEMP_FILE_PREFIX
+# define SQLITE_TEMP_FILE_PREFIX "etilqs_"
+#endif
+
+/*
+** The following values may be passed as the second argument to
+** sqlite3OsLock(). The various locks exhibit the following semantics:
+**
+** SHARED:    Any number of processes may hold a SHARED lock simultaneously.
+** RESERVED:  A single process may hold a RESERVED lock on a file at
+**            any time. Other processes may hold and obtain new SHARED locks.
+** PENDING:   A single process may hold a PENDING lock on a file at
+**            any one time. Existing SHARED locks may persist, but no new
+**            SHARED locks may be obtained by other processes.
+** EXCLUSIVE: An EXCLUSIVE lock precludes all other locks.
+**
+** PENDING_LOCK may not be passed directly to sqlite3OsLock(). Instead, a
+** process that requests an EXCLUSIVE lock may actually obtain a PENDING
+** lock. This can be upgraded to an EXCLUSIVE lock by a subsequent call to
+** sqlite3OsLock().
+*/
+#define NO_LOCK         0
+#define SHARED_LOCK     1
+#define RESERVED_LOCK   2
+#define PENDING_LOCK    3
+#define EXCLUSIVE_LOCK  4
+
+/*
+** File Locking Notes:  (Mostly about windows but also some info for Unix)
+**
+** We cannot use LockFileEx() or UnlockFileEx() on Win95/98/ME because
+** those functions are not available.  So we use only LockFile() and
+** UnlockFile().
+**
+** LockFile() prevents not just writing but also reading by other processes.
+** A SHARED_LOCK is obtained by locking a single randomly-chosen 
+** byte out of a specific range of bytes. The lock byte is obtained at 
+** random so two separate readers can probably access the file at the 
+** same time, unless they are unlucky and choose the same lock byte.
+** An EXCLUSIVE_LOCK is obtained by locking all bytes in the range.
+** There can only be one writer.  A RESERVED_LOCK is obtained by locking
+** a single byte of the file that is designated as the reserved lock byte.
+** A PENDING_LOCK is obtained by locking a designated byte different from
+** the RESERVED_LOCK byte.
+**
+** On WinNT/2K/XP systems, LockFileEx() and UnlockFileEx() are available,
+** which means we can use reader/writer locks.  When reader/writer locks
+** are used, the lock is placed on the same range of bytes that is used
+** for probabilistic locking in Win95/98/ME.  Hence, the locking scheme
+** will support two or more Win95 readers or two or more WinNT readers.
+** But a single Win95 reader will lock out all WinNT readers and a single
+** WinNT reader will lock out all other Win95 readers.
+**
+** The following #defines specify the range of bytes used for locking.
+** SHARED_SIZE is the number of bytes available in the pool from which
+** a random byte is selected for a shared lock.  The pool of bytes for
+** shared locks begins at SHARED_FIRST. 
+**
+** The same locking strategy and
+** byte ranges are used for Unix.  This leaves open the possiblity of having
+** clients on win95, winNT, and unix all talking to the same shared file
+** and all locking correctly.  To do so would require that samba (or whatever
+** tool is being used for file sharing) implements locks correctly between
+** windows and unix.  I'm guessing that isn't likely to happen, but by
+** using the same locking range we are at least open to the possibility.
+**
+** Locking in windows is manditory.  For this reason, we cannot store
+** actual data in the bytes used for locking.  The pager never allocates
+** the pages involved in locking therefore.  SHARED_SIZE is selected so
+** that all locks will fit on a single page even at the minimum page size.
+** PENDING_BYTE defines the beginning of the locks.  By default PENDING_BYTE
+** is set high so that we don't have to allocate an unused page except
+** for very large databases.  But one should test the page skipping logic 
+** by setting PENDING_BYTE low and running the entire regression suite.
+**
+** Changing the value of PENDING_BYTE results in a subtly incompatible
+** file format.  Depending on how it is changed, you might not notice
+** the incompatibility right away, even running a full regression test.
+** The default location of PENDING_BYTE is the first byte past the
+** 1GB boundary.
+**
+*/
+#ifdef SQLITE_OMIT_WSD
+# define PENDING_BYTE     (0x40000000)
+#else
+# define PENDING_BYTE      sqlite3PendingByte
+#endif
+#define RESERVED_BYTE     (PENDING_BYTE+1)
+#define SHARED_FIRST      (PENDING_BYTE+2)
+#define SHARED_SIZE       510
+
+/*
+** Wrapper around OS specific sqlite3_os_init() function.
+*/
+int sqlite3OsInit(void);
+
+/* 
+** Functions for accessing sqlite3_file methods 
+*/
+int sqlite3OsClose(sqlite3_file*);
+int sqlite3OsRead(sqlite3_file*, void*, int amt, i64 offset);
+int sqlite3OsWrite(sqlite3_file*, const void*, int amt, i64 offset);
+int sqlite3OsTruncate(sqlite3_file*, i64 size);
+int sqlite3OsSync(sqlite3_file*, int);
+int sqlite3OsFileSize(sqlite3_file*, i64 *pSize);
+int sqlite3OsLock(sqlite3_file*, int);
+int sqlite3OsUnlock(sqlite3_file*, int);
+int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
+int sqlite3OsFileControl(sqlite3_file*,int,void*);
+#define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
+int sqlite3OsSectorSize(sqlite3_file *id);
+int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
+int sqlite3OsShmMap(sqlite3_file *,int,int,int,void volatile **);
+int sqlite3OsShmLock(sqlite3_file *id, int, int, int);
+void sqlite3OsShmBarrier(sqlite3_file *id);
+int sqlite3OsShmUnmap(sqlite3_file *id, int);
+
+/* 
+** Functions for accessing sqlite3_vfs methods 
+*/
+int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *);
+int sqlite3OsDelete(sqlite3_vfs *, const char *, int);
+int sqlite3OsAccess(sqlite3_vfs *, const char *, int, int *pResOut);
+int sqlite3OsFullPathname(sqlite3_vfs *, const char *, int, char *);
+#ifndef SQLITE_OMIT_LOAD_EXTENSION
+void *sqlite3OsDlOpen(sqlite3_vfs *, const char *);
+void sqlite3OsDlError(sqlite3_vfs *, int, char *);
+void (*sqlite3OsDlSym(sqlite3_vfs *, void *, const char *))(void);
+void sqlite3OsDlClose(sqlite3_vfs *, void *);
+#endif /* SQLITE_OMIT_LOAD_EXTENSION */
+int sqlite3OsRandomness(sqlite3_vfs *, int, char *);
+int sqlite3OsSleep(sqlite3_vfs *, int);
+int sqlite3OsCurrentTimeInt64(sqlite3_vfs *, sqlite3_int64*);
+
+/*
+** Convenience functions for opening and closing files using 
+** sqlite3_malloc() to obtain space for the file-handle structure.
+*/
+int sqlite3OsOpenMalloc(sqlite3_vfs *, const char *, sqlite3_file **, int,int*);
+int sqlite3OsCloseFree(sqlite3_file *);
+
+#endif /* _SQLITE_OS_H_ */