SQLite

** threadsafe.  Failure to heed these warnings can lead to unpredictable
** behavior.
*/
int sqlite3_config(int op, ...){
  va_list ap;
  int rc = SQLITE_OK;

  /* sqlite3_config() normally returns SQLITE_MISUSE if it is invoked while
  ** the SQLite library is in use.  Except, a few selected opcodes
  ** are allowed.
  */
  if( sqlite3GlobalConfig.isInit ){
    static const u64 mAnytimeConfigOption = 0
       | MASKBIT64( SQLITE_CONFIG_LOG )
       | MASKBIT64( SQLITE_CONFIG_URI )
       | MASKBIT64( SQLITE_CONFIG_PCACHE_HDRSZ )
    ;
    if( op<0 || op>63 || (MASKBIT64(op) & mAnytimeConfigOption)==0 ){
      return SQLITE_MISUSE_BKPT;
    }
    testcase( op==SQLITE_CONFIG_LOG );
    testcase( op==SQLITE_CONFIG_URI );
    testcase( op==SQLITE_CONFIG_PCACHE_HDRSZ );
  }

  va_start(ap, op);
  switch( op ){

    /* Mutex configuration options are only available in a threadsafe
    ** compile.
    */

      ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
      ** filled with the currently defined memory allocation routines. */
      if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
      *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
      break;
    }
    case SQLITE_CONFIG_MEMSTATUS: {
      assert( !sqlite3GlobalConfig.isInit );  /* Cannot change at runtime */
      /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
      ** single argument of type int, interpreted as a boolean, which enables
      ** or disables the collection of memory allocation statistics. */
      sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
      break;
    }
    case SQLITE_CONFIG_SMALL_MALLOC: {

    */
    case SQLITE_CONFIG_LOG: {
      /* MSVC is picky about pulling func ptrs from va lists.
      ** http://support.microsoft.com/kb/47961
      ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
      */
      typedef void(*LOGFUNC_t)(void*,int,const char*);
      LOGFUNC_t xLog = va_arg(ap, LOGFUNC_t);
      void *pLogArg = va_arg(ap, void*);
      AtomicStore(&sqlite3GlobalConfig.xLog, xLog);
      AtomicStore(&sqlite3GlobalConfig.pLogArg, pLogArg);
      break;
    }

    /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
    ** can be changed at start-time using the
    ** sqlite3_config(SQLITE_CONFIG_URI,1) or
    ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
    */
    case SQLITE_CONFIG_URI: {
      /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
      ** argument of type int. If non-zero, then URI handling is globally
      ** enabled. If the parameter is zero, then URI handling is globally
      ** disabled. */
      int bOpenUri = va_arg(ap, int);
      AtomicStore(&sqlite3GlobalConfig.bOpenUri, bOpenUri);
      break;
    }

    case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
      /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
      ** option takes a single integer argument which is interpreted as a
      ** boolean in order to enable or disable the use of covering indices for

  const char *zVfs = zDefaultVfs;
  char *zFile;
  char c;
  int nUri = sqlite3Strlen30(zUri);

  assert( *pzErrMsg==0 );

  if( ((flags & SQLITE_OPEN_URI)                     /* IMP: R-48725-32206 */
       || AtomicLoad(&sqlite3GlobalConfig.bOpenUri)) /* IMP: R-51689-46548 */
   && nUri>=5 && memcmp(zUri, "file:", 5)==0         /* IMP: R-57884-37496 */
  ){
    char *zOpt;
    int eState;                   /* Parser state when parsing URI */
    int iIn;                      /* Input character index */
    int iOut = 0;                 /* Output character index */
    u64 nByte = nUri+8;           /* Bytes of space to allocate */

** applications and so this routine is usually not necessary.  It is
** provided to support rare applications with unusual needs.
**
** <b>The sqlite3_config() interface is not threadsafe. The application
** must ensure that no other SQLite interfaces are invoked by other
** threads while sqlite3_config() is running.</b>
**








** The first argument to sqlite3_config() is an integer
** [configuration option] that determines
** what property of SQLite is to be configured.  Subsequent arguments
** vary depending on the [configuration option]
** in the first argument.
**
** For most configuration options, the sqlite3_config() interface
** may only be invoked prior to library initialization using
** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
** The exceptional configuration options that may be invoked at any time
** are called "anytime configuration options".
** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
** [sqlite3_shutdown()] with a first argument that is not an anytime
** configuration option, then the sqlite3_config() call will return SQLITE_MISUSE.
** Note, however, that ^sqlite3_config() can be called as part of the
** implementation of an application-defined [sqlite3_os_init()].
**
** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
** ^If the option is unknown or SQLite is unable to set the option
** then this routine returns a non-zero [error code].
*/
int sqlite3_config(int, ...);

/*
** CAPI3REF: Configuration Options
** KEYWORDS: {configuration option}
**
** These constants are the available integer configuration options that
** can be passed as the first argument to the [sqlite3_config()] interface.
**
** Most of the configuration options for sqlite3_config()
** will only work if invoked prior to [sqlite3_initialize()] or after
** [sqlite3_shutdown()].  The few exceptions to this rule are called
** "anytime configuration options".
** ^Calling [sqlite3_config()] with a first argument that is not an
** anytime configuration option in between calls to [sqlite3_initialize()] and
** [sqlite3_shutdown()] is a no-op that returns SQLITE_MISUSE.
**
** The set of anytime configuration options can change (by insertions
** and/or deletions) from one release of SQLite to the next.
** As of SQLite version 3.42.0, the complete set of anytime configuration
** options is:
** <ul>
** <li> SQLITE_CONFIG_LOG
** <li> SQLITE_CONFIG_URI
** <li> SQLITE_CONFIG_PCACHE_HDRSZ
** </ul>
**
** New configuration options may be added in future releases of SQLite.
** Existing configuration options might be discontinued.  Applications
** should check the return code from [sqlite3_config()] to make sure that
** the call worked.  The [sqlite3_config()] interface will return a
** non-zero [error code] if a discontinued or unsupported configuration option
** is invoked.

#pragma warn -ccc /* Condition is always true or false */
#pragma warn -aus /* Assigned value is never used */
#pragma warn -csu /* Comparing signed and unsigned */
#pragma warn -spa /* Suspicious pointer arithmetic */
#endif

/*
** A few places in the code require atomic load/store of aligned
** integer values.
*/
#ifndef __has_extension
# define __has_extension(x) 0     /* compatibility with non-clang compilers */
#endif
#if GCC_VERSION>=4007000 || __has_extension(c_atomic) 
# define SQLITE_ATOMIC_INTRINSICS 1
# define AtomicLoad(PTR)       __atomic_load_n((PTR),__ATOMIC_RELAXED)