public SqliteDataReader ExecuteReader(CommandBehavior behavior, bool want_results, out int rows_affected)
{
Prepare();
// The SQL string may contain multiple sql commands, so the main
// thing to do is have Sqlite iterate through the commands.
// If want_results, only the last command is returned as a
// DataReader. Otherwise, no command is returned as a
// DataReader.
IntPtr psql; // pointer to SQL command
// Sqlite 2 docs say this: By default, SQLite assumes that all data uses a fixed-size 8-bit
// character (iso8859). But if you give the --enable-utf8 option to the configure script, then the
// library assumes UTF-8 variable sized characters. This makes a difference for the LIKE and GLOB
// operators and the LENGTH() and SUBSTR() functions. The static string sqlite_encoding will be set
// to either "UTF-8" or "iso8859" to indicate how the library was compiled. In addition, the sqlite.h
// header file will define one of the macros SQLITE_UTF8 or SQLITE_ISO8859, as appropriate.
//
// We have no way of knowing whether Sqlite 2 expects ISO8859 or UTF-8, but ISO8859 seems to be the
// default. Therefore, we need to use an ISO8859(-1) compatible encoding, like ANSI.
// OTOH, the user may want to specify the encoding of the bytes stored in the database, regardless
// of what Sqlite is treating them as,
// For Sqlite 3, we use the UTF-16 prepare function, so we need a UTF-16 string.
if (parent_conn.Version == 2)
{
psql = Sqlite.StringToHeap(sql.Trim(), parent_conn.Encoding);
}
else
{
psql = Marshal.StringToHGlobalUni(sql.Trim());
}
IntPtr pzTail = psql;
IntPtr errMsgPtr;
parent_conn.StartExec();
rows_affected = 0;
try {
while (true)
{
IntPtr pStmt;
GetNextStatement(pzTail, out pzTail, out pStmt);
if (pStmt == IntPtr.Zero)
{
throw new Exception();
}
// pzTail is positioned after the last byte in the
// statement, which will be the NULL character if
// this was the last statement.
bool last = Marshal.ReadByte(pzTail) == 0;
try {
if (parent_conn.Version == 3)
{
BindParameters3(pStmt);
}
if (last && want_results)
{
return(new SqliteDataReader(this, pStmt, parent_conn.Version));
}
ExecuteStatement(pStmt);
if (last) // rows_affected is only used if !want_results
{
rows_affected = NumChanges();
}
} finally {
if (parent_conn.Version == 3)
{
Sqlite.sqlite3_finalize(pStmt);
}
else
{
Sqlite.sqlite_finalize(pStmt, out errMsgPtr);
}
}
if (last)
{
break;
}
}
return(null);
} finally {
parent_conn.EndExec();
Marshal.FreeHGlobal(psql);
}
}