SQLite

         notify.lo opcodes.lo os.lo os_unix.lo os_win.lo \
         pager.lo pcache.lo pcache1.lo pragma.lo prepare.lo printf.lo \
         random.lo resolve.lo rowset.lo rtree.lo \
         sqlite3session.lo select.lo sqlite3rbu.lo status.lo stmt.lo \
         table.lo threads.lo tokenize.lo treeview.lo trigger.lo \
         update.lo upsert.lo util.lo vacuum.lo \
         vdbeapi.lo vdbeaux.lo vdbeblob.lo vdbemem.lo vdbesort.lo \
         vdbetrace.lo wal.lo walker.lo where.lo wherecode.lo whereexpr.lo \

         window.lo utf.lo vtab.lo
# <</mark>>

# Object files for the amalgamation.
#
LIBOBJS1 = sqlite3.lo

      int i;

      if( !zDetail ) continue;
      nDetail = STRLEN(zDetail);

      for(i=0; i<nDetail; i++){
        const char *zIdx = 0;
        if( memcmp(&zDetail[i], " USING INDEX ", 13)==0 ){
          zIdx = &zDetail[i+13];

        }else if( memcmp(&zDetail[i], " USING COVERING INDEX ", 22)==0 ){

          zIdx = &zDetail[i+22];
        }
        if( zIdx ){
          const char *zSql;
          int nIdx = 0;
          while( zIdx[nIdx]!='\0' && (zIdx[nIdx]!=' ' || zIdx[nIdx+1]!='(') ){
            nIdx++;

2  COMPILATION AND USAGE

  The easiest way to compile and use the ICU extension is to build
  and use it as a dynamically loadable SQLite extension. To do this
  using gcc on *nix:


    gcc -shared icu.c `icu-config --ldflags` -o libSqliteIcu.so

  You may need to add "-I" flags so that gcc can find sqlite3ext.h
  and sqlite3.h. The resulting shared lib, libSqliteIcu.so, may be
  loaded into sqlite in the same way as any other dynamically loadable
  extension.

** This routine is called when the extension is loaded.
** Register the new VFS.
*/
int sqlite3MemdbInit(void){
  sqlite3_vfs *pLower = sqlite3_vfs_find(0);
  int sz = pLower->szOsFile;
  memdb_vfs.pAppData = pLower;
  /* In all known configurations of SQLite, the size of a default
  ** sqlite3_file is greater than the size of a memdb sqlite3_file.
  ** Should that ever change, remove the following NEVER() */



  if( NEVER(sz<sizeof(MemFile)) ) sz = sizeof(MemFile);
  memdb_vfs.szOsFile = sz;
  return sqlite3_vfs_register(&memdb_vfs, 0);
}
#endif /* SQLITE_ENABLE_DESERIALIZE */

  sqlite3_free(zTmpname);
  pFile->pMethod = pAppData ? pAppData->pMethod : &winIoMethod;
  pFile->pVfs = pVfs;
  pFile->h = h;
  if( isReadonly ){
    pFile->ctrlFlags |= WINFILE_RDONLY;
  }

  if( sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE) ){

    pFile->ctrlFlags |= WINFILE_PSOW;
  }
  pFile->lastErrno = NO_ERROR;
  pFile->zPath = zName;
#if SQLITE_MAX_MMAP_SIZE>0
  pFile->hMap = NULL;
  pFile->pMapRegion = 0;

    assert( desiredEnc==SQLITE_UTF8 );
    if( pMem->enc==SQLITE_UTF16LE ){
      /* UTF-16 Little-endian -> UTF-8 */
      while( zIn<zTerm ){
        c = *(zIn++);
        c += (*(zIn++))<<8;
        if( c>=0xd800 && c<0xe000 ){

          if( c>=0xdc00 || zIn>=zTerm ){
            c = 0xfffd;
          }else{
            int c2 = *(zIn++);
            c2 += (*(zIn++))<<8;
            if( c2<0xdc00 || c2>=0xe000 ){
              zIn -= 2;
              c = 0xfffd;
            }else{
              c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
            }
          }







        }
        WRITE_UTF8(z, c);
      }
    }else{
      /* UTF-16 Big-endian -> UTF-8 */
      while( zIn<zTerm ){
        c = (*(zIn++))<<8;
        c += *(zIn++);
        if( c>=0xd800 && c<0xe000 ){

          if( c>=0xdc00 || zIn>=zTerm ){
            c = 0xfffd;
          }else{
            int c2 = (*(zIn++))<<8;
            c2 += *(zIn++);
            if( c2<0xdc00 || c2>=0xe000 ){
              zIn -= 2;
              c = 0xfffd;
            }else{
              c = ((c&0x3ff)<<10) + (c2&0x3ff) + 0x10000;
            }
          }







        }
        WRITE_UTF8(z, c);
      }
    }
    pMem->n = (int)(z - zOut);
  }
  *z = 0;

    }while( aData<aEnd );
  }

  aOut[0] = s1;
  aOut[1] = s2;
}





static void walShmBarrier(Wal *pWal){
  if( pWal->exclusiveMode!=WAL_HEAPMEMORY_MODE ){
    sqlite3OsShmBarrier(pWal->pDbFd);
  }
}














/*
** Write the header information in pWal->hdr into the wal-index.
**
** The checksum on pWal->hdr is updated before it is written.
*/
static void walIndexWriteHdr(Wal *pWal){
  volatile WalIndexHdr *aHdr = walIndexHdr(pWal);
  const int nCksum = offsetof(WalIndexHdr, aCksum);

  assert( pWal->writeLock );
  pWal->hdr.isInit = 1;
  assert( pWal->hdr.iVersion==WAL_VERSION1||pWal->hdr.iVersion==WAL_VERSION2 );
  walChecksumBytes(1, (u8*)&pWal->hdr, nCksum, 0, pWal->hdr.aCksum);

  memcpy((void*)&aHdr[1], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
  walShmBarrier(pWal);
  memcpy((void*)&aHdr[0], (const void*)&pWal->hdr, sizeof(WalIndexHdr));
}

/*
** This function encodes a single frame header and writes it to a buffer

    ** Frames beyond mxSafeFrame might overwrite database pages that are in 
    ** use by active readers and thus cannot be backfilled from the WAL.
    */
    if( bWal2==0 ){
      mxSafeFrame = pWal->hdr.mxFrame;
      mxPage = pWal->hdr.nPage;
      for(i=1; i<WAL_NREADER; i++){
        /* Thread-sanitizer reports that the following is an unsafe read,
        ** as some other thread may be in the process of updating the value
        ** of the aReadMark[] slot. The assumption here is that if that is
        ** happening, the other client may only be increasing the value,
        ** not decreasing it. So assuming either that either the "old" or
        ** "new" version of the value is read, and not some arbitrary value
        ** that would never be written by a real client, things are still 
        ** safe.
        **
        ** Astute readers have pointed out that the assumption stated in the
        ** last sentence of the previous paragraph is not guaranteed to be
        ** true for all conforming systems.  However, the assumption is true
        ** for all compilers and architectures in common use today (circa
        ** 2019-11-27) and the alternatives are both slow and complex, and
        ** so we will continue to go with the current design for now.  If this
        ** bothers you, or if you really are running on a system where aligned
        ** 32-bit reads and writes are not atomic, then you can simply avoid
        ** the use of WAL mode, or only use WAL mode together with
        ** PRAGMA locking_mode=EXCLUSIVE and all will be well.
        */
        u32 y = pInfo->aReadMark[i];
        if( mxSafeFrame>y ){
          assert( y<=pWal->hdr.mxFrame );
          rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(i), 1);
          if( rc==SQLITE_OK ){
            pInfo->aReadMark[i] = (i==1 ? mxSafeFrame : READMARK_NOT_USED);

            walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
          }else if( rc==SQLITE_BUSY ){
            mxSafeFrame = y;
            xBusy = 0;
          }else{
            goto walcheckpoint_out;
          }

** If and only if the read is consistent and the header is different from
** pWal->hdr, then pWal->hdr is updated to the content of the new header
** and *pChanged is set to 1.
**
** If the checksum cannot be verified return non-zero. If the header
** is read successfully and the checksum verified, return zero.
*/
static int walIndexTryHdr(Wal *pWal, int *pChanged){
  WalIndexHdr h1;                 /* Copy of the header content */

  if( walIndexLoadHdr(pWal, &h1) ){
    return 1;
  }

  if( memcmp(&pWal->hdr, &h1, sizeof(WalIndexHdr)) ){

  sqlite3 db :memory:
  db eval {
    PRAGMA encoding=UTF8;
    CREATE TABLE t1(x);
    INSERT INTO t1 VALUES(hex_to_utf16be('D800'));
    SELECT hex(x) FROM t1;
  }
} {EFBFBD}
do_test tkt-3fe89-1.2 {
  db eval {
    DELETE FROM t1;
    INSERT INTO t1 VALUES(hex_to_utf16le('00D8'));
    SELECT hex(x) FROM t1;
  }
} {EFBFBD}
do_test tkt-3fe89-1.3 {
  db eval {
    DELETE FROM t1;
    INSERT INTO t1 VALUES(hex_to_utf16be('DFFF'));
    SELECT hex(x) FROM t1;
  }
} {EFBFBD}
do_test tkt-3fe89-1.4 {
  db eval {
    DELETE FROM t1;
    INSERT INTO t1 VALUES(hex_to_utf16le('FFDF'));
    SELECT hex(x) FROM t1;
  }
} {EFBFBD}


finish_test