pypyodbc.py

# -*- coding: utf-8 -*-

# PyPyODBC is develped from RealPyODBC 0.1 beta released in 2004 by Michele Petrazzo. Thanks Michele.

# The MIT License (MIT)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated 
# documentation files (the "Software"), to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all copies or substantial portions 
# of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO 
# THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO #EVENT SHALL THE 
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
# DEALINGS IN THE SOFTWARE.

pooling = True
apilevel = '2.0'
paramstyle = 'qmark'
threadsafety = 1
version = '1.0.4'
lowercase=True

DEBUG = 0
# Comment out all "if DEBUG:" statements like below for production
#if DEBUG:print 'DEBUGGING'

import sys, os, datetime, ctypes, threading
from decimal import Decimal


py_ver = sys.version[:3]
py_v3 = py_ver >= '3.0'

if py_v3:
    long = int
    unicode = str
    str_8b = bytes
    buffer = memoryview
else:
    str_8b = str
if py_ver < '2.6':
    bytearray = str
    

if not hasattr(ctypes, 'c_ssize_t'):
    if ctypes.sizeof(ctypes.c_uint) == ctypes.sizeof(ctypes.c_void_p):
        ctypes.c_ssize_t = ctypes.c_int
    elif ctypes.sizeof(ctypes.c_ulong) == ctypes.sizeof(ctypes.c_void_p):
        ctypes.c_ssize_t = ctypes.c_long
    elif ctypes.sizeof(ctypes.c_ulonglong) == ctypes.sizeof(ctypes.c_void_p):
        ctypes.c_ssize_t = ctypes.c_longlong


lock = threading.Lock()
shared_env_h = None
SQLWCHAR_SIZE = ctypes.sizeof(ctypes.c_wchar)

#determin the size of Py_UNICODE
#sys.maxunicode > 65536 and 'UCS4' or 'UCS2'
UNICODE_SIZE = sys.maxunicode > 65536 and 4 or 2 


# Define ODBC constants. They are widly used in ODBC documents and programs
# They are defined in cpp header files: sql.h sqlext.h sqltypes.h sqlucode.h
# and you can get these files from the mingw32-runtime_3.13-1_all.deb package
SQL_ATTR_ODBC_VERSION, SQL_OV_ODBC2, SQL_OV_ODBC3 = 200, 2, 3
SQL_DRIVER_NOPROMPT = 0
SQL_ATTR_CONNECTION_POOLING = 201; SQL_CP_ONE_PER_HENV = 2

SQL_FETCH_NEXT, SQL_FETCH_FIRST, SQL_FETCH_LAST = 0x01, 0x02, 0x04
SQL_NULL_HANDLE, SQL_HANDLE_ENV, SQL_HANDLE_DBC, SQL_HANDLE_STMT = 0, 1, 2, 3
SQL_SUCCESS, SQL_SUCCESS_WITH_INFO = 0, 1
SQL_NO_DATA = 100; SQL_NO_TOTAL = -4
SQL_ATTR_ACCESS_MODE = SQL_ACCESS_MODE = 101
SQL_ATTR_AUTOCOMMIT = SQL_AUTOCOMMIT = 102

SQL_MODE_DEFAULT = SQL_MODE_READ_WRITE = 0; SQL_MODE_READ_ONLY = 1
SQL_AUTOCOMMIT_OFF, SQL_AUTOCOMMIT_ON = 0, 1
SQL_IS_UINTEGER = -5
SQL_ATTR_LOGIN_TIMEOUT = 103; SQL_ATTR_CONNECTION_TIMEOUT = 113
SQL_COMMIT, SQL_ROLLBACK = 0, 1

SQL_INDEX_UNIQUE,SQL_INDEX_ALL = 0,1
SQL_QUICK,SQL_ENSURE = 0,1
SQL_FETCH_NEXT = 1
SQL_COLUMN_DISPLAY_SIZE = 6
SQL_INVALID_HANDLE = -2
SQL_NO_DATA_FOUND = 100; SQL_NULL_DATA = -1; SQL_NTS = -3
SQL_HANDLE_DESCR = 4
SQL_TABLE_NAMES = 3
SQL_PARAM_INPUT = 1; SQL_PARAM_INPUT_OUTPUT = 2
SQL_PARAM_TYPE_UNKNOWN = 0
SQL_RESULT_COL = 3
SQL_PARAM_OUTPUT = 4
SQL_RETURN_VALUE = 5
SQL_PARAM_TYPE_DEFAULT = SQL_PARAM_INPUT_OUTPUT

SQL_RESET_PARAMS = 3
SQL_UNBIND = 2
SQL_CLOSE = 0

SQL_TYPE_NULL = 0
SQL_DECIMAL = 3
SQL_FLOAT = 6
SQL_DATE = 9
SQL_TIME = 10
SQL_TIMESTAMP = 11
SQL_VARCHAR = 12
SQL_LONGVARCHAR = -1
SQL_VARBINARY = -3
SQL_LONGVARBINARY = -4
SQL_BIGINT = -5
SQL_WVARCHAR = -9
SQL_WLONGVARCHAR = -10
SQL_ALL_TYPES = 0
SQL_SIGNED_OFFSET = -20
SQL_SS_VARIANT = -150
SQL_SS_UDT = -151
SQL_SS_TIME2 = -154

SQL_C_CHAR =            SQL_CHAR =          1
SQL_C_NUMERIC =         SQL_NUMERIC =       2
SQL_C_LONG =            SQL_INTEGER =       4
SQL_C_SLONG =           SQL_C_LONG + SQL_SIGNED_OFFSET
SQL_C_SHORT =           SQL_SMALLINT =      5
SQL_C_FLOAT =           SQL_REAL =          7
SQL_C_DOUBLE =          SQL_DOUBLE =        8
SQL_C_TYPE_DATE =       SQL_TYPE_DATE =     91
SQL_C_TYPE_TIME =       SQL_TYPE_TIME =     92
SQL_C_BINARY =          SQL_BINARY =        -2
SQL_C_SBIGINT =         SQL_BIGINT + SQL_SIGNED_OFFSET        
SQL_C_TINYINT =         SQL_TINYINT =       -6
SQL_C_BIT =             SQL_BIT =           -7
SQL_C_WCHAR =           SQL_WCHAR =         -8
SQL_C_GUID =            SQL_GUID =          -11  
SQL_C_TYPE_TIMESTAMP =  SQL_TYPE_TIMESTAMP = 93
SQL_C_DEFAULT = 99

SQL_DESC_DISPLAY_SIZE = SQL_COLUMN_DISPLAY_SIZE



# Below defines The constants for sqlgetinfo method, and their coresponding return types
SQL_QUALIFIER_LOCATION = 114
SQL_QUALIFIER_NAME_SEPARATOR = 41
SQL_QUALIFIER_TERM = 42
SQL_QUALIFIER_USAGE = 92
SQL_OWNER_TERM = 39
SQL_OWNER_USAGE = 91
SQL_ACCESSIBLE_PROCEDURES = 20
SQL_ACCESSIBLE_TABLES = 19
SQL_ACTIVE_ENVIRONMENTS = 116
SQL_AGGREGATE_FUNCTIONS = 169
SQL_ALTER_DOMAIN = 117
SQL_ALTER_TABLE = 86
SQL_ASYNC_MODE = 10021
SQL_BATCH_ROW_COUNT = 120
SQL_BATCH_SUPPORT = 121
SQL_BOOKMARK_PERSISTENCE = 82
SQL_CATALOG_LOCATION = SQL_QUALIFIER_LOCATION
SQL_CATALOG_NAME = 10003
SQL_CATALOG_NAME_SEPARATOR = SQL_QUALIFIER_NAME_SEPARATOR
SQL_CATALOG_TERM = SQL_QUALIFIER_TERM
SQL_CATALOG_USAGE = SQL_QUALIFIER_USAGE
SQL_COLLATION_SEQ = 10004
SQL_COLUMN_ALIAS = 87
SQL_CONCAT_NULL_BEHAVIOR = 22
SQL_CONVERT_FUNCTIONS = 48
SQL_CONVERT_VARCHAR = 70
SQL_CORRELATION_NAME = 74
SQL_CREATE_ASSERTION = 127
SQL_CREATE_CHARACTER_SET = 128
SQL_CREATE_COLLATION = 129
SQL_CREATE_DOMAIN = 130
SQL_CREATE_SCHEMA = 131
SQL_CREATE_TABLE = 132
SQL_CREATE_TRANSLATION = 133
SQL_CREATE_VIEW = 134
SQL_CURSOR_COMMIT_BEHAVIOR = 23
SQL_CURSOR_ROLLBACK_BEHAVIOR = 24
SQL_DATABASE_NAME = 16
SQL_DATA_SOURCE_NAME = 2
SQL_DATA_SOURCE_READ_ONLY = 25
SQL_DATETIME_LITERALS = 119
SQL_DBMS_NAME = 17
SQL_DBMS_VER = 18
SQL_DDL_INDEX = 170
SQL_DEFAULT_TXN_ISOLATION = 26
SQL_DESCRIBE_PARAMETER = 10002
SQL_DM_VER = 171
SQL_DRIVER_NAME = 6
SQL_DRIVER_ODBC_VER = 77
SQL_DRIVER_VER = 7
SQL_DROP_ASSERTION = 136
SQL_DROP_CHARACTER_SET = 137
SQL_DROP_COLLATION = 138
SQL_DROP_DOMAIN = 139
SQL_DROP_SCHEMA = 140
SQL_DROP_TABLE = 141
SQL_DROP_TRANSLATION = 142
SQL_DROP_VIEW = 143
SQL_DYNAMIC_CURSOR_ATTRIBUTES1 = 144
SQL_DYNAMIC_CURSOR_ATTRIBUTES2 = 145
SQL_EXPRESSIONS_IN_ORDERBY = 27
SQL_FILE_USAGE = 84
SQL_FORWARD_ONLY_CURSOR_ATTRIBUTES1 = 146
SQL_FORWARD_ONLY_CURSOR_ATTRIBUTES2 = 147
SQL_GETDATA_EXTENSIONS = 81
SQL_GROUP_BY = 88
SQL_IDENTIFIER_CASE = 28
SQL_IDENTIFIER_QUOTE_CHAR = 29
SQL_INDEX_KEYWORDS = 148
SQL_INFO_SCHEMA_VIEWS = 149
SQL_INSERT_STATEMENT = 172
SQL_INTEGRITY = 73
SQL_KEYSET_CURSOR_ATTRIBUTES1 = 150
SQL_KEYSET_CURSOR_ATTRIBUTES2 = 151
SQL_KEYWORDS = 89
SQL_LIKE_ESCAPE_CLAUSE = 113
SQL_MAX_ASYNC_CONCURRENT_STATEMENTS = 10022
SQL_MAX_BINARY_LITERAL_LEN = 112
SQL_MAX_CATALOG_NAME_LEN = 34
SQL_MAX_CHAR_LITERAL_LEN = 108
SQL_MAX_COLUMNS_IN_GROUP_BY = 97
SQL_MAX_COLUMNS_IN_INDEX = 98
SQL_MAX_COLUMNS_IN_ORDER_BY = 99
SQL_MAX_COLUMNS_IN_SELECT = 100
SQL_MAX_COLUMNS_IN_TABLE = 101
SQL_MAX_COLUMN_NAME_LEN = 30
SQL_MAX_CONCURRENT_ACTIVITIES = 1
SQL_MAX_CURSOR_NAME_LEN = 31
SQL_MAX_DRIVER_CONNECTIONS = 0
SQL_MAX_IDENTIFIER_LEN = 10005
SQL_MAX_INDEX_SIZE = 102
SQL_MAX_PROCEDURE_NAME_LEN = 33
SQL_MAX_ROW_SIZE = 104
SQL_MAX_ROW_SIZE_INCLUDES_LONG = 103
SQL_MAX_SCHEMA_NAME_LEN = 32
SQL_MAX_STATEMENT_LEN = 105
SQL_MAX_TABLES_IN_SELECT = 106
SQL_MAX_TABLE_NAME_LEN = 35
SQL_MAX_USER_NAME_LEN = 107
SQL_MULTIPLE_ACTIVE_TXN = 37
SQL_MULT_RESULT_SETS = 36
SQL_NEED_LONG_DATA_LEN = 111
SQL_NON_NULLABLE_COLUMNS = 75
SQL_NULL_COLLATION = 85
SQL_NUMERIC_FUNCTIONS = 49
SQL_ODBC_INTERFACE_CONFORMANCE = 152
SQL_ODBC_VER = 10
SQL_OJ_CAPABILITIES = 65003
SQL_ORDER_BY_COLUMNS_IN_SELECT = 90
SQL_PARAM_ARRAY_ROW_COUNTS = 153
SQL_PARAM_ARRAY_SELECTS = 154
SQL_PROCEDURES = 21
SQL_PROCEDURE_TERM = 40
SQL_QUOTED_IDENTIFIER_CASE = 93
SQL_ROW_UPDATES = 11
SQL_SCHEMA_TERM = SQL_OWNER_TERM
SQL_SCHEMA_USAGE = SQL_OWNER_USAGE
SQL_SCROLL_OPTIONS = 44
SQL_SEARCH_PATTERN_ESCAPE = 14
SQL_SERVER_NAME = 13
SQL_SPECIAL_CHARACTERS = 94
SQL_SQL92_DATETIME_FUNCTIONS = 155
SQL_SQL92_FOREIGN_KEY_DELETE_RULE = 156
SQL_SQL92_FOREIGN_KEY_UPDATE_RULE = 157
SQL_SQL92_GRANT = 158
SQL_SQL92_NUMERIC_VALUE_FUNCTIONS = 159
SQL_SQL92_PREDICATES = 160
SQL_SQL92_RELATIONAL_JOIN_OPERATORS = 161
SQL_SQL92_REVOKE = 162
SQL_SQL92_ROW_VALUE_CONSTRUCTOR = 163
SQL_SQL92_STRING_FUNCTIONS = 164
SQL_SQL92_VALUE_EXPRESSIONS = 165
SQL_SQL_CONFORMANCE = 118
SQL_STANDARD_CLI_CONFORMANCE = 166
SQL_STATIC_CURSOR_ATTRIBUTES1 = 167
SQL_STATIC_CURSOR_ATTRIBUTES2 = 168
SQL_STRING_FUNCTIONS = 50
SQL_SUBQUERIES = 95
SQL_SYSTEM_FUNCTIONS = 51
SQL_TABLE_TERM = 45
SQL_TIMEDATE_ADD_INTERVALS = 109
SQL_TIMEDATE_DIFF_INTERVALS = 110
SQL_TIMEDATE_FUNCTIONS = 52
SQL_TXN_CAPABLE = 46
SQL_TXN_ISOLATION_OPTION = 72
SQL_UNION = 96
SQL_USER_NAME = 47
SQL_XOPEN_CLI_YEAR = 10000


aInfoTypes = {
SQL_ACCESSIBLE_PROCEDURES : 'GI_YESNO',SQL_ACCESSIBLE_TABLES : 'GI_YESNO',SQL_ACTIVE_ENVIRONMENTS : 'GI_USMALLINT',
SQL_AGGREGATE_FUNCTIONS : 'GI_UINTEGER',SQL_ALTER_DOMAIN : 'GI_UINTEGER',
SQL_ALTER_TABLE : 'GI_UINTEGER',SQL_ASYNC_MODE : 'GI_UINTEGER',SQL_BATCH_ROW_COUNT : 'GI_UINTEGER',
SQL_BATCH_SUPPORT : 'GI_UINTEGER',SQL_BOOKMARK_PERSISTENCE : 'GI_UINTEGER',SQL_CATALOG_LOCATION : 'GI_USMALLINT',
SQL_CATALOG_NAME : 'GI_YESNO',SQL_CATALOG_NAME_SEPARATOR : 'GI_STRING',SQL_CATALOG_TERM : 'GI_STRING',
SQL_CATALOG_USAGE : 'GI_UINTEGER',SQL_COLLATION_SEQ : 'GI_STRING',SQL_COLUMN_ALIAS : 'GI_YESNO',
SQL_CONCAT_NULL_BEHAVIOR : 'GI_USMALLINT',SQL_CONVERT_FUNCTIONS : 'GI_UINTEGER',SQL_CONVERT_VARCHAR : 'GI_UINTEGER',
SQL_CORRELATION_NAME : 'GI_USMALLINT',SQL_CREATE_ASSERTION : 'GI_UINTEGER',SQL_CREATE_CHARACTER_SET : 'GI_UINTEGER',
SQL_CREATE_COLLATION : 'GI_UINTEGER',SQL_CREATE_DOMAIN : 'GI_UINTEGER',SQL_CREATE_SCHEMA : 'GI_UINTEGER',
SQL_CREATE_TABLE : 'GI_UINTEGER',SQL_CREATE_TRANSLATION : 'GI_UINTEGER',SQL_CREATE_VIEW : 'GI_UINTEGER',
SQL_CURSOR_COMMIT_BEHAVIOR : 'GI_USMALLINT',SQL_CURSOR_ROLLBACK_BEHAVIOR : 'GI_USMALLINT',SQL_DATABASE_NAME : 'GI_STRING',
SQL_DATA_SOURCE_NAME : 'GI_STRING',SQL_DATA_SOURCE_READ_ONLY : 'GI_YESNO',SQL_DATETIME_LITERALS : 'GI_UINTEGER',
SQL_DBMS_NAME : 'GI_STRING',SQL_DBMS_VER : 'GI_STRING',SQL_DDL_INDEX : 'GI_UINTEGER',
SQL_DEFAULT_TXN_ISOLATION : 'GI_UINTEGER',SQL_DESCRIBE_PARAMETER : 'GI_YESNO',SQL_DM_VER : 'GI_STRING',
SQL_DRIVER_NAME : 'GI_STRING',SQL_DRIVER_ODBC_VER : 'GI_STRING',SQL_DRIVER_VER : 'GI_STRING',SQL_DROP_ASSERTION : 'GI_UINTEGER',
SQL_DROP_CHARACTER_SET : 'GI_UINTEGER', SQL_DROP_COLLATION : 'GI_UINTEGER',SQL_DROP_DOMAIN : 'GI_UINTEGER',
SQL_DROP_SCHEMA : 'GI_UINTEGER',SQL_DROP_TABLE : 'GI_UINTEGER',SQL_DROP_TRANSLATION : 'GI_UINTEGER',
SQL_DROP_VIEW : 'GI_UINTEGER',SQL_DYNAMIC_CURSOR_ATTRIBUTES1 : 'GI_UINTEGER',SQL_DYNAMIC_CURSOR_ATTRIBUTES2 : 'GI_UINTEGER',
SQL_EXPRESSIONS_IN_ORDERBY : 'GI_YESNO',SQL_FILE_USAGE : 'GI_USMALLINT',
SQL_FORWARD_ONLY_CURSOR_ATTRIBUTES1 : 'GI_UINTEGER',SQL_FORWARD_ONLY_CURSOR_ATTRIBUTES2 : 'GI_UINTEGER',
SQL_GETDATA_EXTENSIONS : 'GI_UINTEGER',SQL_GROUP_BY : 'GI_USMALLINT',SQL_IDENTIFIER_CASE : 'GI_USMALLINT',
SQL_IDENTIFIER_QUOTE_CHAR : 'GI_STRING',SQL_INDEX_KEYWORDS : 'GI_UINTEGER',SQL_INFO_SCHEMA_VIEWS : 'GI_UINTEGER',
SQL_INSERT_STATEMENT : 'GI_UINTEGER',SQL_INTEGRITY : 'GI_YESNO',SQL_KEYSET_CURSOR_ATTRIBUTES1 : 'GI_UINTEGER',
SQL_KEYSET_CURSOR_ATTRIBUTES2 : 'GI_UINTEGER',SQL_KEYWORDS : 'GI_STRING',
SQL_LIKE_ESCAPE_CLAUSE : 'GI_YESNO',SQL_MAX_ASYNC_CONCURRENT_STATEMENTS : 'GI_UINTEGER',
SQL_MAX_BINARY_LITERAL_LEN : 'GI_UINTEGER',SQL_MAX_CATALOG_NAME_LEN : 'GI_USMALLINT',
SQL_MAX_CHAR_LITERAL_LEN : 'GI_UINTEGER',SQL_MAX_COLUMNS_IN_GROUP_BY : 'GI_USMALLINT',
SQL_MAX_COLUMNS_IN_INDEX : 'GI_USMALLINT',SQL_MAX_COLUMNS_IN_ORDER_BY : 'GI_USMALLINT',
SQL_MAX_COLUMNS_IN_SELECT : 'GI_USMALLINT',SQL_MAX_COLUMNS_IN_TABLE : 'GI_USMALLINT',
SQL_MAX_COLUMN_NAME_LEN : 'GI_USMALLINT',SQL_MAX_CONCURRENT_ACTIVITIES : 'GI_USMALLINT',
SQL_MAX_CURSOR_NAME_LEN : 'GI_USMALLINT',SQL_MAX_DRIVER_CONNECTIONS : 'GI_USMALLINT',
SQL_MAX_IDENTIFIER_LEN : 'GI_USMALLINT',SQL_MAX_INDEX_SIZE : 'GI_UINTEGER',
SQL_MAX_PROCEDURE_NAME_LEN : 'GI_USMALLINT',SQL_MAX_ROW_SIZE : 'GI_UINTEGER',
SQL_MAX_ROW_SIZE_INCLUDES_LONG : 'GI_YESNO',SQL_MAX_SCHEMA_NAME_LEN : 'GI_USMALLINT',
SQL_MAX_STATEMENT_LEN : 'GI_UINTEGER',SQL_MAX_TABLES_IN_SELECT : 'GI_USMALLINT',
SQL_MAX_TABLE_NAME_LEN : 'GI_USMALLINT',SQL_MAX_USER_NAME_LEN : 'GI_USMALLINT',
SQL_MULTIPLE_ACTIVE_TXN : 'GI_YESNO',SQL_MULT_RESULT_SETS : 'GI_YESNO',
SQL_NEED_LONG_DATA_LEN : 'GI_YESNO',SQL_NON_NULLABLE_COLUMNS : 'GI_USMALLINT',
SQL_NULL_COLLATION : 'GI_USMALLINT',SQL_NUMERIC_FUNCTIONS : 'GI_UINTEGER',
SQL_ODBC_INTERFACE_CONFORMANCE : 'GI_UINTEGER',SQL_ODBC_VER : 'GI_STRING',SQL_OJ_CAPABILITIES : 'GI_UINTEGER',
SQL_ORDER_BY_COLUMNS_IN_SELECT : 'GI_YESNO',SQL_PARAM_ARRAY_ROW_COUNTS : 'GI_UINTEGER',
SQL_PARAM_ARRAY_SELECTS : 'GI_UINTEGER',SQL_PROCEDURES : 'GI_YESNO',SQL_PROCEDURE_TERM : 'GI_STRING',
SQL_QUOTED_IDENTIFIER_CASE : 'GI_USMALLINT',SQL_ROW_UPDATES : 'GI_YESNO',SQL_SCHEMA_TERM : 'GI_STRING',
SQL_SCHEMA_USAGE : 'GI_UINTEGER',SQL_SCROLL_OPTIONS : 'GI_UINTEGER',SQL_SEARCH_PATTERN_ESCAPE : 'GI_STRING',
SQL_SERVER_NAME : 'GI_STRING',SQL_SPECIAL_CHARACTERS : 'GI_STRING',SQL_SQL92_DATETIME_FUNCTIONS : 'GI_UINTEGER',
SQL_SQL92_FOREIGN_KEY_DELETE_RULE : 'GI_UINTEGER',SQL_SQL92_FOREIGN_KEY_UPDATE_RULE : 'GI_UINTEGER',
SQL_SQL92_GRANT : 'GI_UINTEGER',SQL_SQL92_NUMERIC_VALUE_FUNCTIONS : 'GI_UINTEGER',
SQL_SQL92_PREDICATES : 'GI_UINTEGER',SQL_SQL92_RELATIONAL_JOIN_OPERATORS : 'GI_UINTEGER',
SQL_SQL92_REVOKE : 'GI_UINTEGER',SQL_SQL92_ROW_VALUE_CONSTRUCTOR : 'GI_UINTEGER',
SQL_SQL92_STRING_FUNCTIONS : 'GI_UINTEGER',SQL_SQL92_VALUE_EXPRESSIONS : 'GI_UINTEGER',
SQL_SQL_CONFORMANCE : 'GI_UINTEGER',SQL_STANDARD_CLI_CONFORMANCE : 'GI_UINTEGER',
SQL_STATIC_CURSOR_ATTRIBUTES1 : 'GI_UINTEGER',SQL_STATIC_CURSOR_ATTRIBUTES2 : 'GI_UINTEGER',
SQL_STRING_FUNCTIONS : 'GI_UINTEGER',SQL_SUBQUERIES : 'GI_UINTEGER',
SQL_SYSTEM_FUNCTIONS : 'GI_UINTEGER',SQL_TABLE_TERM : 'GI_STRING',SQL_TIMEDATE_ADD_INTERVALS : 'GI_UINTEGER',
SQL_TIMEDATE_DIFF_INTERVALS : 'GI_UINTEGER',SQL_TIMEDATE_FUNCTIONS : 'GI_UINTEGER',
SQL_TXN_CAPABLE : 'GI_USMALLINT',SQL_TXN_ISOLATION_OPTION : 'GI_UINTEGER',
SQL_UNION : 'GI_UINTEGER',SQL_USER_NAME : 'GI_STRING',SQL_XOPEN_CLI_YEAR : 'GI_STRING',
}

#Definations for types
BINARY = bytearray
Binary = bytearray
DATETIME = datetime.datetime
Date = datetime.date
Time = datetime.time
Timestamp = datetime.datetime
STRING = str
NUMBER = float
ROWID = int
DateFromTicks = datetime.date.fromtimestamp
TimeFromTicks = lambda x: datetime.datetime.fromtimestamp(x).time()
TimestampFromTicks = datetime.datetime.fromtimestamp


#Define exceptions
class OdbcNoLibrary(Exception):
    def __init__(self, value):
        self.value = value
    def __str__(self):
        return repr(self.value)
class OdbcLibraryError(Exception):
    def __init__(self, value):
        self.value = value
    def __str__(self):
        return repr(self.value)
class OdbcInvalidHandle(Exception):
    def __init__(self, value):
        self.value = value
    def __str__(self):
        return repr(self.value)
class OdbcGenericError(Exception):
    def __init__(self, value):
        self.value = value
    def __str__(self):
        return repr(self.value)
class Warning(Exception):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class Error(Exception):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class InterfaceError(Error):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class DatabaseError(Error):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class InternalError(DatabaseError):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class ProgrammingError(DatabaseError):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class DataError(DatabaseError):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class IntegrityError(DatabaseError):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class NotSupportedError(Error):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)
class OperationalError(DatabaseError):
    def __init__(self, error_code, error_desc):
        self.value = (error_code, error_desc)
        self.args = (error_code, error_desc)


# Get the References of the platform's ODBC functions via ctypes 
if sys.platform in ('win32','cli'):
    ODBC_API = ctypes.windll.odbc32
    # On Windows, the size of SQLWCHAR is hardcoded to 2-bytes.
    SQLWCHAR_SIZE = ctypes.sizeof(ctypes.c_ushort)
else:
    # Set load the library on linux 
    try:
        # First try direct loading libodbc.so
        ODBC_API = ctypes.cdll.LoadLibrary('libodbc.so')
    except:
        # If direct loading libodbc.so failed
        # We try finding the libodbc.so by using find_library
        from ctypes.util import find_library
        library = find_library('odbc')
        if library is None:
            # If find_library still can not find the library
            # we try finding it manually from where libodbc.so usually appears
            lib_paths = ("/usr/lib/libodbc.so","/usr/lib/i386-linux-gnu/libodbc.so","/usr/lib/x86_64-linux-gnu/libodbc.so")
            lib_paths = [path for path in lib_paths if os.path.exists(path)]
            if len(lib_paths) == 0 :
                raise OdbcNoLibrary('ODBC Library is not found')
            else:
                library = lib_paths[0]

        # Then we try loading the found libodbc.so again
        try:
            ODBC_API = ctypes.cdll.LoadLibrary(library)
        except:
            # If still fail loading, abort.
            raise OdbcLibraryError('Error while loading ' + library)

    # unixODBC defaults to 2-bytes SQLWCHAR, unless "-DSQL_WCHART_CONVERT" was
    # added to CFLAGS, in which case it will be the size of wchar_t.
    # Note that using 4-bytes SQLWCHAR will break most ODBC drivers, as driver
    # development mostly targets the Windows platform.
    if py_v3:
        from subprocess import getstatusoutput
    else:
        from commands import getstatusoutput

    status, output = getstatusoutput('odbc_config --cflags')
    if status == 0 and 'SQL_WCHART_CONVERT' in output:
        SQLWCHAR_SIZE = ctypes.sizeof(ctypes.c_wchar)
    else:
        SQLWCHAR_SIZE = ctypes.sizeof(ctypes.c_ushort)


create_buffer_u = ctypes.create_unicode_buffer
create_buffer = ctypes.create_string_buffer
wchar_pointer = ctypes.c_wchar_p
ucs2_buf = lambda s: s
def ucs2_dec(buffer):
    i = 0
    uchars = []
    while True:
        uchar = buffer.raw[i:i + 2].decode('utf_16')
        if uchar == unicode('\x00'):
            break
        uchars.append(uchar)
        i += 2
    return ''.join(uchars)
from_buffer_u = lambda buffer: buffer.value

# This is the common case on Linux, which uses wide Python build together with
# the default unixODBC without the "-DSQL_WCHART_CONVERT" CFLAGS.
if sys.platform not in ('win32','cli'):
    if UNICODE_SIZE > SQLWCHAR_SIZE:
        # We can only use unicode buffer if the size of wchar_t (UNICODE_SIZE) is
        # the same as the size expected by the driver manager (SQLWCHAR_SIZE).
        create_buffer_u = create_buffer
        wchar_pointer = ctypes.c_char_p

        def ucs2_buf(s):
            return s.encode('utf_16_le')

        from_buffer_u = ucs2_dec

    # Exoteric case, don't really care.
    elif UNICODE_SIZE < SQLWCHAR_SIZE:
        raise OdbcLibraryError('Using narrow Python build with ODBC library '
            'expecting wide unicode is not supported.')

#################
# Database value to Python data type mappings

def dttm_cvt(x):
    if py_v3:
        x = x.decode('ascii')
    if x == '': return None
    else: return datetime.datetime(int(x[0:4]),int(x[5:7]),int(x[8:10]),int(x[10:13]),int(x[14:16]),int(x[17:19]),int(x[20:].ljust(6,'0')))

def tm_cvt(x):
    if py_v3:
        x = x.decode('ascii')
    if x == '': return None
    else: return datetime.time(int(x[0:2]),int(x[3:5]),int(x[6:8]),int(x[9:].ljust(6,'0')))

def dt_cvt(x):
    if py_v3:
        x = x.decode('ascii')
    if x == '': return None
    else: return datetime.date(int(x[0:4]),int(x[5:7]),int(x[8:10]))

def Decimal_cvt(x):
    if py_v3:
        x = x.decode('ascii')    
    return Decimal(x)
    
bytearray_cvt = bytearray
if sys.platform == 'cli':
    bytearray_cvt = lambda x: bytearray(buffer(x))
    
# Below Datatype mappings referenced the document at
# http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.sdk_12.5.1.aseodbc/html/aseodbc/CACFDIGH.htm

SQL_data_type_dict = { \
#SQL Data TYPE        0.Python Data Type     1.Default Output Converter  2.Buffer Type     3.Buffer Allocator   4.Default Buffer Size
SQL_TYPE_NULL       : (None,                lambda x: None,             SQL_C_CHAR,         create_buffer,      2      ), 
SQL_CHAR            : (str,                 lambda x: x,                SQL_C_CHAR,         create_buffer,      2048   ),
SQL_NUMERIC         : (Decimal,             Decimal_cvt,                SQL_C_CHAR,         create_buffer,      150    ),
SQL_DECIMAL         : (Decimal,             Decimal_cvt,                SQL_C_CHAR,         create_buffer,      150    ),
SQL_INTEGER         : (int,                 int,                        SQL_C_CHAR,         create_buffer,      150    ),
SQL_SMALLINT        : (int,                 int,                        SQL_C_CHAR,         create_buffer,      150    ),
SQL_FLOAT           : (float,               float,                      SQL_C_CHAR,         create_buffer,      150    ),
SQL_REAL            : (float,               float,                      SQL_C_CHAR,         create_buffer,      150    ),
SQL_DOUBLE          : (float,               float,                      SQL_C_CHAR,         create_buffer,      200    ),
SQL_DATE            : (datetime.date,       dt_cvt,                     SQL_C_CHAR ,        create_buffer,      30     ),
SQL_TIME            : (datetime.time,       tm_cvt,                     SQL_C_CHAR,         create_buffer,      20     ),
SQL_SS_TIME2        : (datetime.time,       tm_cvt,                     SQL_C_CHAR,         create_buffer,      20     ),
SQL_TIMESTAMP       : (datetime.datetime,   dttm_cvt,                   SQL_C_CHAR,         create_buffer,      30     ),
SQL_VARCHAR         : (str,                 lambda x: x,                SQL_C_CHAR,         create_buffer,      2048   ),
SQL_LONGVARCHAR     : (str,                 lambda x: x,                SQL_C_CHAR,         create_buffer,      20500  ),
SQL_BINARY          : (bytearray,           bytearray_cvt,                  SQL_C_BINARY,       create_buffer,      5120   ),
SQL_VARBINARY       : (bytearray,           bytearray_cvt,                  SQL_C_BINARY,       create_buffer,      5120   ),
SQL_LONGVARBINARY   : (bytearray,           bytearray_cvt,                  SQL_C_BINARY,       create_buffer,      20500  ),
SQL_BIGINT          : (long,                long,                       SQL_C_CHAR,         create_buffer,      150    ),
SQL_TINYINT         : (int,                 int,                        SQL_C_CHAR,         create_buffer,      150    ),
SQL_BIT             : (bool,                lambda x:x=='1',            SQL_C_CHAR,         create_buffer,      2      ),
SQL_WCHAR           : (unicode,             lambda x: x,                SQL_C_WCHAR,        create_buffer_u,    2048   ),
SQL_WVARCHAR        : (unicode,             lambda x: x,                SQL_C_WCHAR,        create_buffer_u,    2048   ),
SQL_GUID            : (str,                 str,                        SQL_C_CHAR,         create_buffer,      50     ),
SQL_WLONGVARCHAR    : (unicode,             lambda x: x,                SQL_C_WCHAR,        create_buffer_u,    20500  ),
SQL_TYPE_DATE       : (datetime.date,       dt_cvt,                     SQL_C_CHAR,         create_buffer,      30     ),
SQL_TYPE_TIME       : (datetime.time,       tm_cvt,                     SQL_C_CHAR,         create_buffer,      20     ),
SQL_TYPE_TIMESTAMP  : (datetime.datetime,   dttm_cvt,                   SQL_C_CHAR,         create_buffer,      30      ), 
SQL_SS_VARIANT      : (str,                 lambda x: x,                SQL_C_CHAR,         create_buffer,      2048   ), 
SQL_SS_UDT          : (bytearray,           bytearray_cvt,                  SQL_C_BINARY,       create_buffer,      5120   ),
}


"""
Types mapping, applicable for 32-bit and 64-bit Linux / Windows / Mac OS X.

SQLPointer -> ctypes.c_void_p
SQLCHAR * -> ctypes.c_char_p
SQLWCHAR * -> ctypes.c_wchar_p on Windows, ctypes.c_char_p with unixODBC
SQLINT -> ctypes.c_int
SQLSMALLINT -> ctypes.c_short
SQMUSMALLINT -> ctypes.c_ushort
SQLLEN -> ctypes.c_ssize_t
SQLULEN -> ctypes.c_size_t
SQLRETURN -> ctypes.c_short
"""

# Define the python return type for ODBC functions with ret result.
funcs_with_ret = [
    "SQLAllocHandle",
    "SQLBindParameter",
    "SQLCloseCursor",
    "SQLColAttribute",
    "SQLColumns",
    "SQLColumnsW",
    "SQLConnect",
    "SQLConnectW",
    "SQLDataSources",
    "SQLDataSourcesW",
    "SQLDescribeCol",
    "SQLDescribeColW",
    "SQLDescribeParam",
    "SQLDisconnect",
    "SQLDriverConnect",
    "SQLDriverConnectW",
    "SQLEndTran",
    "SQLExecDirect",
    "SQLExecDirectW",
    "SQLExecute",
    "SQLFetch",
    "SQLFetchScroll",
    "SQLForeignKeys",
    "SQLForeignKeysW",
    "SQLFreeHandle",
    "SQLFreeStmt",
    "SQLGetData",
    "SQLGetDiagRec",
    "SQLGetDiagRecW",
    "SQLGetInfo",
    "SQLGetInfoW",
    "SQLGetTypeInfo",
    "SQLMoreResults",
    "SQLNumParams",
    "SQLNumResultCols",
    "SQLPrepare",
    "SQLPrepareW",
    "SQLPrimaryKeys",
    "SQLPrimaryKeysW",
    "SQLProcedureColumns",
    "SQLProcedureColumnsW",
    "SQLProcedures",
    "SQLProceduresW",
    "SQLRowCount",
    "SQLSetConnectAttr",
    "SQLSetEnvAttr",
    "SQLStatistics",
    "SQLStatisticsW",
    "SQLTables",
    "SQLTablesW",
]

for func_name in funcs_with_ret:
    getattr(ODBC_API, func_name).restype = ctypes.c_short

if sys.platform not in ('cli'):
    #Seems like the IronPython can not declare ctypes.POINTER type arguments
    ODBC_API.SQLAllocHandle.argtypes = [
        ctypes.c_short,
        ctypes.c_void_p,
        ctypes.POINTER(ctypes.c_void_p),
    ]

    ODBC_API.SQLBindParameter.argtypes = [
        ctypes.c_void_p,
        ctypes.c_ushort,
        ctypes.c_short,
        ctypes.c_short,
        ctypes.c_short,
        ctypes.c_size_t,
        ctypes.c_short,
        ctypes.c_void_p,
        ctypes.c_ssize_t,
        ctypes.POINTER(ctypes.c_ssize_t),
    ]

    ODBC_API.SQLColAttribute.argtypes = [
        ctypes.c_void_p,
        ctypes.c_ushort,
        ctypes.c_ushort,
        ctypes.c_void_p,
        ctypes.c_short,
        ctypes.POINTER(ctypes.c_short),
        ctypes.POINTER(ctypes.c_ssize_t),
    ]

    ODBC_API.SQLDataSources.argtypes = [
        ctypes.c_void_p,
        ctypes.c_ushort,
        ctypes.c_char_p,
        ctypes.c_short,
        ctypes.POINTER(ctypes.c_short),
        ctypes.c_char_p,
        ctypes.c_short,
        ctypes.POINTER(ctypes.c_short),
    ]

    ODBC_API.SQLDescribeCol.argtypes = [
        ctypes.c_void_p,
        ctypes.c_ushort,
        ctypes.c_char_p,
        ctypes.c_short,
        ctypes.POINTER(ctypes.c_short),
        ctypes.POINTER(ctypes.c_short),
        ctypes.POINTER(ctypes.c_size_t),
        ctypes.POINTER(ctypes.c_short),
        ctypes.POINTER(ctypes.c_short),
    ]

    ODBC_API.SQLDescribeParam.argtypes = [
        ctypes.c_void_p,
        ctypes.c_ushort,
        ctypes.POINTER(ctypes.c_short),
        ctypes.POINTER(ctypes.c_size_t),
        ctypes.POINTER(ctypes.c_short),
        ctypes.POINTER(ctypes.c_short),
    ]

    ODBC_API.SQLDriverConnect.argtypes = [
        ctypes.c_void_p,
        ctypes.c_void_p,
        ctypes.c_char_p,
        ctypes.c_short,
        ctypes.c_char_p,
        ctypes.c_short,
        ctypes.POINTER(ctypes.c_short),
        ctypes.c_ushort,
    ]

    ODBC_API.SQLGetData.argtypes = [
        ctypes.c_void_p,
        ctypes.c_ushort,
        ctypes.c_short,
        ctypes.c_void_p,
        ctypes.c_ssize_t,
        ctypes.POINTER(ctypes.c_ssize_t),
    ]

    ODBC_API.SQLGetDiagRec.argtypes = [
        ctypes.c_short,
        ctypes.c_void_p,
        ctypes.c_short,
        ctypes.c_char_p,
        ctypes.POINTER(ctypes.c_int),
        ctypes.c_char_p,
        ctypes.c_short,
        ctypes.POINTER(ctypes.c_short),
    ]

    ODBC_API.SQLGetInfo.argtypes = [
        ctypes.c_void_p,
        ctypes.c_ushort,
        ctypes.c_void_p,
        ctypes.c_short,
        ctypes.POINTER(ctypes.c_short),
    ]

    ODBC_API.SQLRowCount.argtypes = [
        ctypes.c_void_p,
        ctypes.POINTER(ctypes.c_ssize_t),
    ]

    ODBC_API.SQLNumParams.argtypes = [
        ctypes.c_void_p,
        ctypes.POINTER(ctypes.c_short),
    ]

    ODBC_API.SQLNumResultCols.argtypes = [
        ctypes.c_void_p,
        ctypes.POINTER(ctypes.c_short),
    ]


ODBC_API.SQLCloseCursor.argtypes = [ctypes.c_void_p]

ODBC_API.SQLColumns.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
]

ODBC_API.SQLConnect.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
]



ODBC_API.SQLDisconnect.argtypes = [ctypes.c_void_p]


ODBC_API.SQLEndTran.argtypes = [
    ctypes.c_short,
    ctypes.c_void_p,
    ctypes.c_short,
]

ODBC_API.SQLExecute.argtypes = [ctypes.c_void_p]

ODBC_API.SQLExecDirect.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_int,
]

ODBC_API.SQLFetch.argtypes = [ctypes.c_void_p]

ODBC_API.SQLFetchScroll.argtypes = [
    ctypes.c_void_p,
    ctypes.c_short,
    ctypes.c_ssize_t,
]

ODBC_API.SQLForeignKeys.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
]

ODBC_API.SQLFreeHandle.argtypes = [
    ctypes.c_short,
    ctypes.c_void_p,
]

ODBC_API.SQLFreeStmt.argtypes = [
    ctypes.c_void_p,
    ctypes.c_ushort,
]


ODBC_API.SQLGetTypeInfo.argtypes = [
    ctypes.c_void_p,
    ctypes.c_short,
]

ODBC_API.SQLMoreResults.argtypes = [ctypes.c_void_p]


ODBC_API.SQLPrepare.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_int,
]

ODBC_API.SQLPrimaryKeys.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
]

ODBC_API.SQLProcedureColumns.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
]

ODBC_API.SQLProcedures.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
]


ODBC_API.SQLSetConnectAttr.argtypes = [
    ctypes.c_void_p,
    ctypes.c_int,
    ctypes.c_void_p,
    ctypes.c_int,
]

ODBC_API.SQLSetEnvAttr.argtypes = [
    ctypes.c_void_p,
    ctypes.c_int,
    ctypes.c_void_p,
    ctypes.c_int,
]

ODBC_API.SQLStatistics.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_ushort,
    ctypes.c_ushort,
]

ODBC_API.SQLTables.argtypes = [
    ctypes.c_void_p,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
    ctypes.c_char_p,
    ctypes.c_short,
]

def to_wchar(argtypes):
    if argtypes: # Under IronPython some argtypes are not declared
        result = []
        for x in argtypes:
            if x == ctypes.c_char_p:
                result.append(wchar_pointer)
            else:
                result.append(x)
        return result
    else:
        return argtypes

ODBC_API.SQLColumnsW.argtypes = to_wchar(ODBC_API.SQLColumns.argtypes)
ODBC_API.SQLConnectW.argtypes = to_wchar(ODBC_API.SQLConnect.argtypes)
ODBC_API.SQLDataSourcesW.argtypes = to_wchar(ODBC_API.SQLDataSources.argtypes)
ODBC_API.SQLDescribeColW.argtypes = to_wchar(ODBC_API.SQLDescribeCol.argtypes)
ODBC_API.SQLDriverConnectW.argtypes = to_wchar(ODBC_API.SQLDriverConnect.argtypes)
ODBC_API.SQLExecDirectW.argtypes = to_wchar(ODBC_API.SQLExecDirect.argtypes)
ODBC_API.SQLForeignKeysW.argtypes = to_wchar(ODBC_API.SQLForeignKeys.argtypes)
ODBC_API.SQLPrepareW.argtypes = to_wchar(ODBC_API.SQLPrepare.argtypes)
ODBC_API.SQLPrimaryKeysW.argtypes = to_wchar(ODBC_API.SQLPrimaryKeys.argtypes)
ODBC_API.SQLProcedureColumnsW.argtypes = to_wchar(ODBC_API.SQLProcedureColumns.argtypes)
ODBC_API.SQLProceduresW.argtypes = to_wchar(ODBC_API.SQLProcedures.argtypes)
ODBC_API.SQLStatisticsW.argtypes = to_wchar(ODBC_API.SQLStatistics.argtypes)
ODBC_API.SQLTablesW.argtypes = to_wchar(ODBC_API.SQLTables.argtypes)
ODBC_API.SQLGetDiagRecW.argtypes = to_wchar(ODBC_API.SQLGetDiagRec.argtypes)
ODBC_API.SQLGetInfoW.argtypes = to_wchar(ODBC_API.SQLGetInfo.argtypes)

# Set the alias for the ctypes functions for beter code readbility or performance.
ADDR = ctypes.byref
SQLFetch = ODBC_API.SQLFetch
SQLExecute = ODBC_API.SQLExecute
SQLBindParameter = ODBC_API.SQLBindParameter
# Set alias for beter code readbility or performance.
NO_FREE_STATEMENT = 0
FREE_STATEMENT = 1

def ctrl_err(ht, h, val_ret, ansi):
    """Classify type of ODBC error from (type of handle, handle, return value)
    , and raise with a list"""
    
    if ansi:
        state = create_buffer(22)
        Message = create_buffer(1024*10)
        ODBC_func = ODBC_API.SQLGetDiagRec
    else:
        state = create_buffer_u(22)
        Message = create_buffer_u(1024*10)
        ODBC_func = ODBC_API.SQLGetDiagRecW
    NativeError = ctypes.c_int()
    Buffer_len = ctypes.c_short()
    err_list = []
    number_errors = 1
    
    while 1:
        ret = ODBC_func(ht, h, number_errors, state, \
            NativeError, Message, len(Message), ADDR(Buffer_len))
        if ret == SQL_NO_DATA_FOUND:
            #No more data, I can raise
            #if DEBUG:print(err_list[0][1])
            state = err_list[0][0]
            err_text = '['+state+'] '+err_list[0][1]
            if state[:2] in (unicode('24'),unicode('25'),unicode('42')):
                raise ProgrammingError(state,err_text)
            elif state[:2] in (unicode('22')):
                raise DataError(state,err_text)
            elif state[:2] in (unicode('23')) or state == unicode('40002'):
                raise IntegrityError(state,err_text)
            elif state == unicode('0A000'):
                raise NotSupportedError(state,err_text)
            elif state in (unicode('HYT00'),unicode('HYT01')):
                raise OperationalError(state,err_text)
            elif state[:2] in (unicode('IM'),unicode('HY')):
                raise Error(state,err_text)
            else:
                raise DatabaseError(state,err_text)
            break
        elif ret == SQL_INVALID_HANDLE:
            #The handle passed is an invalid handle
            raise ProgrammingError('', 'SQL_INVALID_HANDLE')
        elif ret == SQL_SUCCESS:
            if ansi:
                err_list.append((state.value, Message.value, NativeError.value))
            else:
                err_list.append((from_buffer_u(state), from_buffer_u(Message), NativeError.value))
            number_errors += 1



def check_success(ODBC_obj, ret):
    """ Validate return value, if not success, raise exceptions based on the handle """
    if ret not in (SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_NO_DATA):
        if isinstance(ODBC_obj, Cursor):
            ctrl_err(SQL_HANDLE_STMT, ODBC_obj.stmt_h, ret, ODBC_obj.ansi)
        elif isinstance(ODBC_obj, Connection):
            ctrl_err(SQL_HANDLE_DBC, ODBC_obj.dbc_h, ret, ODBC_obj.ansi)
        else:
            ctrl_err(SQL_HANDLE_ENV, ODBC_obj, ret, False)
            
            
def AllocateEnv():
    if pooling:
        ret = ODBC_API.SQLSetEnvAttr(SQL_NULL_HANDLE, SQL_ATTR_CONNECTION_POOLING, SQL_CP_ONE_PER_HENV, SQL_IS_UINTEGER)
        check_success(SQL_NULL_HANDLE, ret)

    ''' 
    Allocate an ODBC environment by initializing the handle shared_env_h
    ODBC enviroment needed to be created, so connections can be created under it
    connections pooling can be shared under one environment
    '''
    global shared_env_h 
    shared_env_h  = ctypes.c_void_p()
    ret = ODBC_API.SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, ADDR(shared_env_h))
    check_success(shared_env_h, ret)

    # Set the ODBC environment's compatibil leve to ODBC 3.0
    ret = ODBC_API.SQLSetEnvAttr(shared_env_h, SQL_ATTR_ODBC_VERSION, SQL_OV_ODBC3, 0)
    check_success(shared_env_h, ret)
    

"""
Here, we have a few callables that determine how a result row is returned.

A new one can be added by creating a callable that:
- accepts a cursor as its parameter.
- returns a callable that accepts an iterable containing the row values.
"""

def TupleRow(cursor):
    """Normal tuple with added attribute `cursor_description`, as in pyodbc.

    This is the default.
    """
    class Row(tuple):
        cursor_description = cursor.description

    return Row


def NamedTupleRow(cursor):
    """Named tuple to allow attribute lookup by name.

    Requires py2.6 or above.
    """
    from collections import namedtuple

    attr_names = [x[0] for x in cursor._ColBufferList]

    class Row(namedtuple('Row', attr_names, rename=True)):
        cursor_description = cursor.description

        def __new__(cls, iterable):
            return super(Row, cls).__new__(cls, *iterable)

    return Row


def MutableNamedTupleRow(cursor):
    """Mutable named tuple to allow attribute to be replaced. This should be
    compatible with pyodbc's Row type.

    Requires 3rd-party library "recordtype".
    """
    from recordtype import recordtype

    attr_names = [x[0] for x in cursor._ColBufferList]

    class Row(recordtype('Row', attr_names, rename=True)):
        cursor_description = cursor.description

        def __init__(self, iterable):
            super(Row, self).__init__(*iterable)

        def __iter__(self):
            for field_name in self.__slots__:
                yield getattr(self, field_name)

        def __getitem__(self, index):
            if isinstance(index, slice):
                return tuple(getattr(self, x) for x in self.__slots__[index])
            return getattr(self, self.__slots__[index])

        def __setitem__(self, index, value):
            setattr(self, self.__slots__[index], value)

    return Row


# The get_type function is used to determine if parameters need to be re-binded 
# against the changed parameter types
def get_type(v):
    t = type(v)
    
    if py_v3:
        if isinstance(v, bytes):
            if len(v) >= 255:
                t = 's'
    if isinstance(v, str):
        if len(v) >= 255:
            if py_v3:
                t = 'u'
            else:
                t = 's'
    elif isinstance(v, (int, long)):
        #SQL_BIGINT defination: http://msdn.microsoft.com/en-us/library/ms187745.aspx
        if v > 2147483647 or v < -2147483648:
            t = 'l'
        else:
            t = 'i'
    elif isinstance(v, unicode):
        if len(v) >= 255:
            t = 'u'
    elif isinstance(v, Decimal):
        sv = str(v).replace('-','').strip('0').split('.')
        if len(sv)>1:
            t = (len(sv[0])+len(sv[1]),len(sv[1]))
        else:
            t = (len(sv[0]),0)
    return t


# The Cursor Class.
class Cursor:
    def __init__(self, conx, row_type_callable=None):
        """ Initialize self.stmt_h, which is the handle of a statement
        A statement is actually the basis of a python"cursor" object
        """
        self.stmt_h = ctypes.c_void_p()
        self.connection = conx
        self.ansi = conx.ansi
        self.row_type_callable = row_type_callable or TupleRow
        self.statement = None
        self._last_param_types = None
        self._ParamBufferList = []
        self._ColBufferList = []
        self._row_type = None
        self._buf_cvt_func = []
        self.rowcount = -1
        self.description = None
        self.autocommit = None
        self._ColTypeCodeList = []
        self._outputsize = {}
        self._inputsizers = []
        self.arraysize = 1
        ret = ODBC_API.SQLAllocHandle(SQL_HANDLE_STMT, self.connection.dbc_h, ADDR(self.stmt_h))
        check_success(self, ret)
        self.closed = False

    
    def execute(self, query_string, params=None, many_mode=False, call_mode=False):
        """ Execute the query string, with optional parameters.
        If parameters are provided, the query would first be prepared, then executed with parameters;
        If parameters are not provided, only th query sting, it would be executed directly 
        """

        self._free_results(FREE_STATEMENT)

        if params:
            # If parameters exist, first prepare the query then executed with parameters
            if not type(params) in (tuple, list, set):
                raise TypeError("Params must be in a list, tuple, or set")
            
            if not many_mode:
                if query_string != self.statement:
                    # if the query is not same as last query, then it is not prepared
                    self.prepare(query_string)
            
    
            param_types = list(map(get_type, params))

            if call_mode:
                self._BindParams(param_types, self._pram_io_list)
            else:
                if param_types != self._last_param_types:
                    self._BindParams(param_types)
                
            
            # With query prepared, now put parameters into buffers
            col_num = 0
            for param_buffer, param_buffer_len, sql_type in self._ParamBufferList:
                c_char_buf, c_buf_len = '', 0
                param_val = params[col_num]
                if param_val is None:
                    c_buf_len = SQL_NULL_DATA
                    
                elif isinstance(param_val, datetime.datetime):
                    max_len = self.connection.type_size_dic[SQL_TYPE_TIMESTAMP][0]
                    datetime_str = param_val.strftime('%Y-%m-%d %H:%M:%S.%f')
                    c_char_buf = datetime_str[:max_len]
                    c_buf_len = len(c_char_buf)
                    # print c_buf_len, c_char_buf
                    
                elif isinstance(param_val, datetime.date):
                    if SQL_TYPE_DATE in self.connection.type_size_dic:
                        max_len = self.connection.type_size_dic[SQL_TYPE_DATE][0]
                    else:
                        max_len = 10
                    c_char_buf = param_val.isoformat()[:max_len]
                    c_buf_len = len(c_char_buf)
                    #print c_char_buf
                    
                elif isinstance(param_val, datetime.time):
                    if SQL_TYPE_TIME in self.connection.type_size_dic:
                        max_len = self.connection.type_size_dic[SQL_TYPE_TIME][0]
                        c_char_buf = param_val.isoformat()[:max_len]
                        c_buf_len = len(c_char_buf)
                    elif SQL_SS_TIME2 in self.connection.type_size_dic:
                        max_len = self.connection.type_size_dic[SQL_SS_TIME2][0]
                        c_char_buf = param_val.isoformat()[:max_len]
                        c_buf_len = len(c_char_buf)
                    else:
                        c_buf_len = self.connection.type_size_dic[SQL_TYPE_TIMESTAMP][0]
                        time_str = param_val.isoformat()
                        if len(time_str) == 8:
                            time_str += '.000'
                        c_char_buf = '1900-01-01 '+time_str[0:c_buf_len - 11]
                    #print c_buf_len, c_char_buf
                    
                elif isinstance(param_val, bool):
                    if param_val == True:
                        c_char_buf = '1'
                    else:
                        c_char_buf = '0'
                    c_buf_len = 1
                    
                elif isinstance(param_val, (int, long, float, Decimal)):
                    if py_v3:
                        c_char_buf = bytes(str(param_val),'ascii')
                    else:
                        c_char_buf = str(param_val)
                    c_buf_len = len(c_char_buf)
                    
                elif isinstance(param_val, str_8b):
                    c_char_buf = param_val
                    c_buf_len = len(c_char_buf)
                elif isinstance(param_val, unicode):
                    c_char_buf = ucs2_buf(param_val)
                    c_buf_len = len(c_char_buf)
                elif isinstance(param_val, (bytearray, buffer)):
                    c_char_buf = str(param_val)
                    c_buf_len = len(c_char_buf)
                    
                else:
                    c_char_buf = param_val
            
    
                if isinstance(param_val, (bytearray, buffer)):
                    param_buffer.raw = str_8b(param_val)
                    
                else:
                    param_buffer.value = c_char_buf
                    #print param_buffer, param_buffer.value
                    
                if isinstance(param_val, (unicode, str)):
                    #ODBC driver will find NUL in unicode and string to determine their length
                    param_buffer_len.value = SQL_NTS
                else:
                    param_buffer_len.value = c_buf_len
    
                col_num += 1
            ret = SQLExecute(self.stmt_h)
            if ret != SQL_SUCCESS:
                check_success(self, ret)
            

            if not many_mode:
                self._NumOfRows()
                self._UpdateDesc()
                #self._BindCols()
            
        else:
            self.execdirect(query_string)
        return (self)
    
    
    def _SQLExecute(self):
        ret = SQLExecute(self.stmt_h)
        if ret != SQL_SUCCESS:
            check_success(self, ret)        

            
    def prepare(self, query_string):
        """prepare a query"""
        if type(query_string) == unicode:
            c_query_string = wchar_pointer(ucs2_buf(query_string))
            ret = ODBC_API.SQLPrepareW(self.stmt_h, c_query_string, len(query_string))
        else:
            c_query_string = ctypes.c_char_p(query_string)
            ret = ODBC_API.SQLPrepare(self.stmt_h, c_query_string, len(query_string))
        if ret != SQL_SUCCESS:
            check_success(self, ret)
        self.statement = query_string
        
    
    def execdirect(self, query_string):
        """Execute a query directly"""
        if type(query_string) == unicode:
            c_query_string = wchar_pointer(ucs2_buf(query_string))
            ret = ODBC_API.SQLExecDirectW(self.stmt_h, c_query_string, len(query_string))
        else:
            c_query_string = ctypes.c_char_p(query_string)
            ret = ODBC_API.SQLExecDirect(self.stmt_h, c_query_string, len(query_string))
        check_success(self, ret)
        self._NumOfRows()
        self._UpdateDesc()
        #self._BindCols()
        self.statement = None
        return (self)
        
        
    def callproc(self, procname, args):
        raise Warning('', 'Still not fully implemented')
        self._pram_io_list = [row[4] for row in self.procedurecolumns(procedure = procname).fetchall() if row[4] not in (SQL_RESULT_COL, SQL_RETURN_VALUE)]
        
        print('pram_io_list: '+str(self._pram_io_list))

        
        
        call_escape = '{CALL '+procname
        if args:
            call_escape += '(' + ','.join(['?' for params in args]) + ')'
        call_escape += '}'

        self.execute(call_escape, args, call_mode = True)
        
        result = []

        for buf, buf_len, sql_type in self._ParamBufferList:
            if buf_len.value == -1:
                result.append(None)
            else:
                result.append(self.connection.output_converter[sql_type](buf.value))
        return (result)
            
                
    
    def executemany(self, query_string, params_list = [None]):
        self.prepare(query_string)
        for params in params_list:
            self.execute(query_string, params, many_mode = True)
        self._NumOfRows()
        self.rowcount = -1
        self._UpdateDesc()
        #self._BindCols()


    def _BindParams(self, param_types, pram_io_list = []):
        """Create parameter buffers based on param types, and bind them to the statement"""
        # Get the number of query parameters judged by database.
        NumParams = ctypes.c_short()
        ret = ODBC_API.SQLNumParams(self.stmt_h, ADDR(NumParams))
        if ret != SQL_SUCCESS:
            check_success(self, ret)
        
        if len(param_types) != NumParams.value:
            # In case number of parameters provided do not same as number required
            error_desc = "The SQL contains %d parameter markers, but %d parameters were supplied" \
                        %(NumParams.value,len(param_types))
            raise ProgrammingError('HY000',error_desc)
        
        
        # Every parameter needs to be binded to a buffer
        ParamBufferList = []
        # Temporary holder since we can only call SQLDescribeParam before
        # calling SQLBindParam.
        temp_holder = []
        for col_num in range(NumParams.value):
            col_size = 0            
            buf_size = 512
        
            if param_types[col_num] == type(None):
                ParameterNumber = ctypes.c_ushort(col_num + 1)
                DataType = ctypes.c_short()
                ParameterSize = ctypes.c_size_t()
                DecimalDigits = ctypes.c_short()
                Nullable = ctypes.c_short()
                ret = ODBC_API.SQLDescribeParam(
                    self.stmt_h,
                    ParameterNumber,
                    ADDR(DataType),
                    ADDR(ParameterSize),
                    ADDR(DecimalDigits),
                    ADDR(Nullable),
                )
                if ret != SQL_SUCCESS:
                    check_success(self, ret)

                sql_c_type = SQL_C_DEFAULT
                sql_type = DataType.value
                buf_size = 1
                ParameterBuffer = create_buffer(buf_size)

            elif param_types[col_num] == 'u':
                sql_c_type = SQL_C_WCHAR
                sql_type = SQL_WLONGVARCHAR
                buf_size = len(self._inputsizers)>col_num and self._inputsizers[col_num] or 20500
                ParameterBuffer = create_buffer_u(buf_size)

            elif param_types[col_num] == 's':
                sql_c_type = SQL_C_CHAR
                sql_type = SQL_LONGVARCHAR
                buf_size = len(self._inputsizers)>col_num and self._inputsizers[col_num] or 20500
                ParameterBuffer = create_buffer(buf_size)
            
            elif param_types[col_num] == 'i':
                sql_c_type = SQL_C_CHAR            
                sql_type = SQL_INTEGER    
                buf_size = SQL_data_type_dict[sql_type][4]             
                ParameterBuffer = create_buffer(buf_size)           
                
            elif param_types[col_num] == 'l':
                sql_c_type = SQL_C_CHAR           
                sql_type = SQL_BIGINT         
                buf_size = SQL_data_type_dict[sql_type][4]         
                ParameterBuffer = create_buffer(buf_size)
            

            elif type(param_types[col_num]) == tuple: #Decimal
                sql_c_type = SQL_C_CHAR
                sql_type = SQL_NUMERIC
                buf_size = param_types[col_num][0]

                ParameterBuffer = create_buffer(buf_size+4)
                col_size = param_types[col_num][1]
                #if DEBUG:print(param_types[col_num][0],param_types[col_num][1])

            # bool subclasses int, thus has to go first
            elif issubclass(param_types[col_num], bool):
                sql_c_type = SQL_C_CHAR
                sql_type = SQL_BIT
                buf_size = SQL_data_type_dict[sql_type][4]
                ParameterBuffer = create_buffer(buf_size)

                
            elif issubclass(param_types[col_num], float):
                sql_c_type = SQL_C_CHAR
                sql_type = SQL_DOUBLE                
                buf_size = SQL_data_type_dict[sql_type][4]  
                ParameterBuffer = create_buffer(buf_size)
                
                
            # datetime subclasses date, thus has to go first
            elif issubclass(param_types[col_num], datetime.datetime):
                sql_c_type = SQL_C_CHAR
                sql_type = SQL_TYPE_TIMESTAMP
                buf_size = self.connection.type_size_dic[SQL_TYPE_TIMESTAMP][0]                
                ParameterBuffer = create_buffer(buf_size)
                col_size = self.connection.type_size_dic[SQL_TYPE_TIMESTAMP][1]
                
                
            elif issubclass(param_types[col_num], datetime.date):
                sql_c_type = SQL_C_CHAR
                if SQL_TYPE_DATE in self.connection.type_size_dic:
                    #if DEBUG:print('conx.type_size_dic.has_key(SQL_TYPE_DATE)')
                    sql_type = SQL_TYPE_DATE
                    buf_size = self.connection.type_size_dic[SQL_TYPE_DATE][0]
                    
                    ParameterBuffer = create_buffer(buf_size)
                    col_size = self.connection.type_size_dic[SQL_TYPE_DATE][1]
                    
                else:
                    # SQL Sever <2008 doesn't have a DATE type.
                    sql_type = SQL_TYPE_TIMESTAMP 
                    buf_size = 10                    
                    ParameterBuffer = create_buffer(buf_size)
                    
    
            elif issubclass(param_types[col_num], datetime.time):
                sql_c_type = SQL_C_CHAR
                if SQL_TYPE_TIME in self.connection.type_size_dic:
                    sql_type = SQL_TYPE_TIME
                    buf_size = self.connection.type_size_dic[SQL_TYPE_TIME][0]                    
                    ParameterBuffer = create_buffer(buf_size)
                    col_size = self.connection.type_size_dic[SQL_TYPE_TIME][1]                   
                elif SQL_SS_TIME2 in self.connection.type_size_dic:
                    # TIME type added in SQL Server 2008
                    sql_type = SQL_SS_TIME2
                    buf_size = self.connection.type_size_dic[SQL_SS_TIME2][0]
                    ParameterBuffer = create_buffer(buf_size)
                    col_size = self.connection.type_size_dic[SQL_SS_TIME2][1]
                else:
                    # SQL Sever <2008 doesn't have a TIME type.
                    sql_type = SQL_TYPE_TIMESTAMP
                    buf_size = self.connection.type_size_dic[SQL_TYPE_TIMESTAMP][0]                    
                    ParameterBuffer = create_buffer(buf_size)
                    col_size = 3
                    
            elif issubclass(param_types[col_num], unicode):
                sql_c_type = SQL_C_WCHAR
                sql_type = SQL_WVARCHAR 
                buf_size = 255                 
                ParameterBuffer = create_buffer_u(buf_size)                
                    
            elif issubclass(param_types[col_num], str_8b):
                sql_c_type = SQL_C_CHAR
                sql_type = SQL_VARCHAR
                buf_size = 255                 
                ParameterBuffer = create_buffer(buf_size)

            elif issubclass(param_types[col_num], (bytearray, buffer)):
                sql_c_type = SQL_C_BINARY
                sql_type = SQL_LONGVARBINARY 
                buf_size = len(self._inputsizers)>col_num and self._inputsizers[col_num] or 20500                
                ParameterBuffer = create_buffer(buf_size)
            
                
            else:
                sql_c_type = SQL_C_CHAR
                sql_type = SQL_LONGVARCHAR
                buf_size = len(self._inputsizers)>col_num and self._inputsizers[col_num] or 20500                
                ParameterBuffer = create_buffer(buf_size)
                
            temp_holder.append((sql_c_type, sql_type, buf_size, col_size, ParameterBuffer))

        for col_num, (sql_c_type, sql_type, buf_size, col_size, ParameterBuffer) in enumerate(temp_holder):
            BufferLen = ctypes.c_ssize_t(buf_size)
            LenOrIndBuf = ctypes.c_ssize_t()
                
            
            InputOutputType = SQL_PARAM_INPUT
            if len(pram_io_list) > col_num:
                InputOutputType = pram_io_list[col_num]

            ret = SQLBindParameter(self.stmt_h, col_num + 1, InputOutputType, sql_c_type, sql_type, buf_size,\
                    col_size, ADDR(ParameterBuffer), BufferLen,ADDR(LenOrIndBuf))
            if ret != SQL_SUCCESS:    
                check_success(self, ret)
            # Append the value buffer and the lenth buffer to the array
            ParamBufferList.append((ParameterBuffer,LenOrIndBuf,sql_type))
                
        self._last_param_types = param_types
        self._ParamBufferList = ParamBufferList
        
    

    def _CreateColBuf(self):
        NOC = self._NumOfCols()
        self._ColBufferList = []
        self._row_type = None
        for col_num in range(NOC):
            col_name = self.description[col_num][0]            
            
            col_sql_data_type = self._ColTypeCodeList[col_num]            

            # set default size base on the column's sql data type
            total_buf_len = SQL_data_type_dict[col_sql_data_type][4] 
            # over-write if there's preset size value for "large columns"
            if total_buf_len >= 20500: 
                total_buf_len = self._outputsize.get(None,total_buf_len)
            # over-write if there's preset size value for the "col_num" column 
            total_buf_len = self._outputsize.get(col_num, total_buf_len)


            alloc_buffer = SQL_data_type_dict[col_sql_data_type][3](total_buf_len)

            used_buf_len = ctypes.c_ssize_t()
            
            target_type = SQL_data_type_dict[col_sql_data_type][2]
            force_unicode = self.connection.unicode_results
    
            if force_unicode and col_sql_data_type in (SQL_CHAR,SQL_VARCHAR,SQL_LONGVARCHAR):
                target_type = SQL_C_WCHAR
                alloc_buffer = create_buffer_u(total_buf_len)
            
            buf_cvt_func = self.connection.output_converter[self._ColTypeCodeList[col_num]]
            
            self._ColBufferList.append([col_name, target_type, used_buf_len, alloc_buffer, total_buf_len, buf_cvt_func])     
        
    
    def _GetData(self):
        '''Bind buffers for the record set columns'''
        
        # Lazily create the row type on first fetch.
        if self._row_type is None:
            self._row_type = self.row_type_callable(self)

        value_list = []
        col_num = 0
        for col_name, target_type, used_buf_len, alloc_buffer, total_buf_len, buf_cvt_func in self._ColBufferList:
            
            blocks = []
            while True:
                ret = ODBC_API.SQLGetData(self.stmt_h, col_num + 1, target_type, ADDR(alloc_buffer), total_buf_len,\
                                ADDR(used_buf_len))
                check_success(self, ret)    
                
                if ret == SQL_SUCCESS:
                    if used_buf_len.value == SQL_NULL_DATA:
                        blocks.append(None)                    
                    else:
                        if target_type == SQL_C_BINARY:
                            blocks.append(alloc_buffer.raw[:used_buf_len.value])
                        elif target_type == SQL_C_WCHAR:
                            blocks.append(from_buffer_u(alloc_buffer))
                        else:
                            #print col_name, target_type, alloc_buffer.value
                            blocks.append(alloc_buffer.value)
                            
                    break                    
                
                if ret == SQL_SUCCESS_WITH_INFO:
                    if target_type == SQL_C_BINARY:
                        blocks.append(alloc_buffer.raw)
                    else:
                        blocks.append(alloc_buffer.value)  
     
                if ret == SQL_NO_DATA:
                    break

                
            if len(blocks) == 0:
                raw_value = None
            elif len(blocks) == 1:
                raw_value = blocks[0]
            else:
                if py_v3:
                    if type(blocks[0]) == str:
                        raw_value = ''.join(blocks)
                    else:
                        raw_value = b''.join(blocks)
                else:
                    raw_value = ''.join(blocks)

            if raw_value == None:
                value_list.append(None)
            else:
                value_list.append(buf_cvt_func(raw_value))
            col_num += 1
        
        return self._row_type(value_list)
        
    
    def _UpdateDesc(self):
        "Get the information of (name, type_code, display_size, internal_size, col_precision, scale, null_ok)"  
        force_unicode = self.connection.unicode_results
        if force_unicode:
            Cname = create_buffer_u(1024)
        else:
            Cname = create_buffer(1024)
        
        Cname_ptr = ctypes.c_short()
        Ctype_code = ctypes.c_short()
        Csize = ctypes.c_size_t()
        Cdisp_size = ctypes.c_ssize_t(0)
        CDecimalDigits = ctypes.c_short()
        Cnull_ok = ctypes.c_short()
        ColDescr = []
        self._ColTypeCodeList = []
        NOC = self._NumOfCols()
        for col in range(1, NOC+1):
            
            ret = ODBC_API.SQLColAttribute(self.stmt_h, col, SQL_DESC_DISPLAY_SIZE, ADDR(create_buffer(10)), 
                10, ADDR(ctypes.c_short()),ADDR(Cdisp_size))
            check_success(self, ret)
            
            if force_unicode:
            
                ret = ODBC_API.SQLDescribeColW(self.stmt_h, col, Cname, len(Cname), ADDR(Cname_ptr),\
                    ADDR(Ctype_code),ADDR(Csize),ADDR(CDecimalDigits), ADDR(Cnull_ok))
                check_success(self, ret)
            else:
                
                ret = ODBC_API.SQLDescribeCol(self.stmt_h, col, Cname, len(Cname), ADDR(Cname_ptr),\
                    ADDR(Ctype_code),ADDR(Csize),ADDR(CDecimalDigits), ADDR(Cnull_ok))
                check_success(self, ret)
            
            col_name = Cname.value
            if lowercase:
                col_name = col_name.lower()
            #(name, type_code, display_size, 

            ColDescr.append((col_name, SQL_data_type_dict.get(Ctype_code.value,(Ctype_code.value,))[0],Cdisp_size.value,\
                Csize.value, Csize.value,CDecimalDigits.value,Cnull_ok.value == 1 and True or False))
            self._ColTypeCodeList.append(Ctype_code.value)
        
        if len(ColDescr) > 0:
            self.description = ColDescr
        else:
            self.description = None
        self._CreateColBuf()
    
    
    def _NumOfRows(self):
        """Get the number of rows"""
        NOR = ctypes.c_ssize_t()
        ret = ODBC_API.SQLRowCount(self.stmt_h, ADDR(NOR))
        check_success(self, ret)
        self.rowcount = NOR.value
        return self.rowcount    

    
    def _NumOfCols(self):
        """Get the number of cols"""
        NOC = ctypes.c_short()
        ret = ODBC_API.SQLNumResultCols(self.stmt_h, ADDR(NOC))
        check_success(self, ret)
        return NOC.value


    def fetchall(self):
        rows = []
        while True:
            row = self.fetchone()
            if row == None:
                break
            rows.append(row)
        return rows


    def fetchmany(self, num = None):
        if num == None:
            num = self.arraysize
        rows, row_num = [], 0
        
        while row_num < num:
            row = self.fetchone()
            if row == None:
                break
            rows.append(row)
            row_num += 1
        return rows


    def fetchone(self):
        ret = SQLFetch(self.stmt_h)
        if ret == SQL_SUCCESS:
            return self._GetData()
        else:
            if ret == SQL_NO_DATA_FOUND:
                return None
            else:
                check_success(self, ret)
                
    def __next__(self):
        self.next()
    
    def next(self):
        row = self.fetchone()
        if row == None:
            raise(StopIteration)
        return row
    
    def __iter__(self):
        return self

    
    def skip(self, count = 0):
        for i in range(count):
            ret = ODBC_API.SQLFetchScroll(self.stmt_h, SQL_FETCH_NEXT, 0)
            if ret != SQL_SUCCESS:
                check_success(self, ret)
        return None    
    
    
        
    def nextset(self):
        ret = ODBC_API.SQLMoreResults(self.stmt_h)
        if ret not in (SQL_SUCCESS, SQL_NO_DATA):
            check_success(self, ret)
            
        if ret == SQL_NO_DATA:
            self._free_results(FREE_STATEMENT)
            return False
        else:
            self._NumOfRows()
            self._UpdateDesc()
            #self._BindCols()
        return True
    
    
    def _free_results(self, free_statement = NO_FREE_STATEMENT):
        if not self.connection.connected:
            raise ProgrammingError('HY000','Attempt to use a closed connection.')
        
        self.description = None
        if free_statement == FREE_STATEMENT:
            ret = ODBC_API.SQLFreeStmt(self.stmt_h, SQL_CLOSE)
            check_success(self, ret)
        else:
            ret = ODBC_API.SQLFreeStmt(self.stmt_h, SQL_UNBIND)
            check_success(self, ret)
            
            ret = ODBC_API.SQLFreeStmt(self.stmt_h, SQL_RESET_PARAMS)
            check_success(self, ret)
    
        self.rowcount = -1
        
    
    
    def getTypeInfo(self, sqlType = None):
        if sqlType == None:
            type = SQL_ALL_TYPES
        else:
            type = sqlType
        ret = ODBC_API.SQLGetTypeInfo(self.stmt_h, type)
        if ret in (SQL_SUCCESS, SQL_SUCCESS_WITH_INFO):
            self._NumOfRows()
            self._UpdateDesc()
            #self._BindCols()
            return self.fetchone()
    
    
    def tables(self, table=None, catalog=None, schema=None, tableType=None):
        """Return a list with all tables""" 
        l_catalog = l_schema = l_table = l_tableType = 0
        
        if unicode in [type(x) for x in (table, catalog, schema,tableType)]:
            string_p = lambda x:wchar_pointer(ucs2_buf(x))
            API_f = ODBC_API.SQLTablesW
        else:
            string_p = ctypes.c_char_p
            API_f = ODBC_API.SQLTables
            
        
        
        if catalog != None:
            l_catalog = len(catalog)
            catalog = string_p(catalog) 

        if schema != None: 
            l_schema = len(schema)
            schema = string_p(schema)
            
        if table != None:
            l_table = len(table)
            table = string_p(table)
            
        if tableType != None: 
            l_tableType = len(tableType)
            tableType = string_p(tableType)
        
        self._free_results(FREE_STATEMENT)
        self.statement = None
        ret = API_f(self.stmt_h,
                                catalog, l_catalog,
                                schema, l_schema, 
                                table, l_table,
                                tableType, l_tableType)
        check_success(self, ret)
    
        self._NumOfRows()
        self._UpdateDesc()
        #self._BindCols()
        return (self)
    
    
    def columns(self, table=None, catalog=None, schema=None, column=None):
        """Return a list with all columns"""        
        l_catalog = l_schema = l_table = l_column = 0
        
        if unicode in [type(x) for x in (table, catalog, schema,column)]:
            string_p = lambda x:wchar_pointer(ucs2_buf(x))
            API_f = ODBC_API.SQLColumnsW
        else:
            string_p = ctypes.c_char_p
            API_f = ODBC_API.SQLColumns
            
        
        
        if catalog != None: 
            l_catalog = len(catalog)
            catalog = string_p(catalog)
        if schema != None:
            l_schema = len(schema)
            schema = string_p(schema)
        if table != None: 
            l_table = len(table)
            table = string_p(table)
        if column != None: 
            l_column = len(column)
            column = string_p(column)
            
        self._free_results(FREE_STATEMENT)
        self.statement = None
            
        ret = API_f(self.stmt_h,
                    catalog, l_catalog,
                    schema, l_schema,
                    table, l_table,
                    column, l_column)
        check_success(self, ret)

        self._NumOfRows()
        self._UpdateDesc()
        #self._BindCols()
        return (self)
    
    
    def primaryKeys(self, table=None, catalog=None, schema=None):
        l_catalog = l_schema = l_table = 0
        
        if unicode in [type(x) for x in (table, catalog, schema)]:
            string_p = lambda x:wchar_pointer(ucs2_buf(x))
            API_f = ODBC_API.SQLPrimaryKeysW
        else:
            string_p = ctypes.c_char_p
            API_f = ODBC_API.SQLPrimaryKeys
            
        
        
        if catalog != None: 
            l_catalog = len(catalog)
            catalog = string_p(catalog)
            
        if schema != None: 
            l_schema = len(schema)
            schema = string_p(schema)
            
        if table != None: 
            l_table = len(table)
            table = string_p(table)
            
        self._free_results(FREE_STATEMENT)
        self.statement = None
            
        ret = API_f(self.stmt_h,
                    catalog, l_catalog,
                    schema, l_schema,
                    table, l_table)
        check_success(self, ret)
        
        self._NumOfRows()
        self._UpdateDesc()
        #self._BindCols()
        return (self)
    
        
    def foreignKeys(self, table=None, catalog=None, schema=None, foreignTable=None, foreignCatalog=None, foreignSchema=None):
        l_catalog = l_schema = l_table = l_foreignTable = l_foreignCatalog = l_foreignSchema = 0
        
        if unicode in [type(x) for x in (table, catalog, schema,foreignTable,foreignCatalog,foreignSchema)]:
            string_p = lambda x:wchar_pointer(ucs2_buf(x))
            API_f = ODBC_API.SQLForeignKeysW
        else:
            string_p = ctypes.c_char_p
            API_f = ODBC_API.SQLForeignKeys
        
        if catalog != None: 
            l_catalog = len(catalog)
            catalog = string_p(catalog)
        if schema != None: 
            l_schema = len(schema)
            schema = string_p(schema)
        if table != None: 
            l_table = len(table)
            table = string_p(table)
        if foreignTable != None: 
            l_foreignTable = len(foreignTable)
            foreignTable = string_p(foreignTable)
        if foreignCatalog != None: 
            l_foreignCatalog = len(foreignCatalog)
            foreignCatalog = string_p(foreignCatalog)
        if foreignSchema != None: 
            l_foreignSchema = len(foreignSchema)
            foreignSchema = string_p(foreignSchema)
        
        self._free_results(FREE_STATEMENT)
        self.statement = None
        
        ret = API_f(self.stmt_h,
                    catalog, l_catalog,
                    schema, l_schema,
                    table, l_table,
                    foreignCatalog, l_foreignCatalog,
                    foreignSchema, l_foreignSchema,
                    foreignTable, l_foreignTable)
        check_success(self, ret)
        
        self._NumOfRows()
        self._UpdateDesc()
        #self._BindCols()
        return (self)
    
    
    def procedurecolumns(self, procedure=None, catalog=None, schema=None, column=None):
        l_catalog = l_schema = l_procedure = l_column = 0
        if unicode in [type(x) for x in (procedure, catalog, schema,column)]:
            string_p = lambda x:wchar_pointer(ucs2_buf(x))
            API_f = ODBC_API.SQLProcedureColumnsW
        else:
            string_p = ctypes.c_char_p
            API_f = ODBC_API.SQLProcedureColumns
            
        
        if catalog != None: 
            l_catalog = len(catalog)
            catalog = string_p(catalog)
        if schema != None: 
            l_schema = len(schema)
            schema = string_p(schema)
        if procedure != None: 
            l_procedure = len(procedure)
            procedure = string_p(procedure)
        if column != None: 
            l_column = len(column)
            column = string_p(column)
            
        
        self._free_results(FREE_STATEMENT)
        self.statement = None
            
        ret = API_f(self.stmt_h,
                    catalog, l_catalog,
                    schema, l_schema,
                    procedure, l_procedure,
                    column, l_column)
        check_success(self, ret)
        
        self._NumOfRows()
        self._UpdateDesc()
        return (self)
        
    
    def procedures(self, procedure=None, catalog=None, schema=None):
        l_catalog = l_schema = l_procedure = 0
        
        if unicode in [type(x) for x in (procedure, catalog, schema)]:
            string_p = lambda x:wchar_pointer(ucs2_buf(x))
            API_f = ODBC_API.SQLProceduresW
        else:
            string_p = ctypes.c_char_p
            API_f = ODBC_API.SQLProcedures
            
        
        
        if catalog != None: 
            l_catalog = len(catalog)
            catalog = string_p(catalog)
        if schema != None: 
            l_schema = len(schema)
            schema = string_p(schema)
        if procedure != None: 
            l_procedure = len(procedure)
            procedure = string_p(procedure)
            
        
        self._free_results(FREE_STATEMENT)
        self.statement = None
            
        ret = API_f(self.stmt_h,
                    catalog, l_catalog,
                    schema, l_schema,
                    procedure, l_procedure)
        check_success(self, ret)
        
        self._NumOfRows()
        self._UpdateDesc()
        return (self)


    def statistics(self, table, catalog=None, schema=None, unique=False, quick=True):
        l_table = l_catalog = l_schema = 0
        
        if unicode in [type(x) for x in (table, catalog, schema)]:
            string_p = lambda x:wchar_pointer(ucs2_buf(x))
            API_f = ODBC_API.SQLStatisticsW
        else:
            string_p = ctypes.c_char_p
            API_f = ODBC_API.SQLStatistics
            
    
        if catalog != None: 
            l_catalog = len(catalog)
            catalog = string_p(catalog)
        if schema != None: 
            l_schema = len(schema)
            schema = string_p(schema)
        if table != None: 
            l_table = len(table)
            table = string_p(table)
            
        if unique:
            Unique = SQL_INDEX_UNIQUE
        else:
            Unique = SQL_INDEX_ALL
        if quick:
            Reserved = SQL_QUICK
        else:
            Reserved = SQL_ENSURE
        
        self._free_results(FREE_STATEMENT)
        self.statement = None
        
        ret = API_f(self.stmt_h,
                    catalog, l_catalog,
                    schema, l_schema, 
                    table, l_table,
                    Unique, Reserved)
        check_success(self, ret)
    
        self._NumOfRows()
        self._UpdateDesc()
        #self._BindCols()
        return (self)
    

    def commit(self):
        self.connection.commit()

    def rollback(self):
        self.connection.rollback()
    
    def setoutputsize(self, size, column = None):
        self._outputsize[column] = size
    
    def setinputsizes(self, sizes):
        self._inputsizers = [size for size in sizes]


    def close(self):
        """ Call SQLCloseCursor API to free the statement handle"""
#        ret = ODBC_API.SQLCloseCursor(self.stmt_h)
#        check_success(self, ret)
#        
        ret = ODBC_API.SQLFreeStmt(self.stmt_h, SQL_CLOSE)
        check_success(self, ret)

        ret = ODBC_API.SQLFreeStmt(self.stmt_h, SQL_UNBIND)
        check_success(self, ret)

        ret = ODBC_API.SQLFreeStmt(self.stmt_h, SQL_RESET_PARAMS)
        check_success(self, ret)

        ret = ODBC_API.SQLFreeHandle(SQL_HANDLE_STMT, self.stmt_h)
        check_success(self, ret)
        
        self.closed = True

    
    
    def __del__(self):  
        if not self.closed:
            #if DEBUG:print 'auto closing cursor: ',
            try:
                self.close()
            except:
                #if DEBUG:print 'failed'
                pass
            else:
                #if DEBUG:print 'succeed'
                pass
    
    def __exit__(self, type, value, traceback):
        if value:
            self.rollback()
        else:
            self.commit()
            
        self.close()
    
            
    def __enter__(self):
        return self

    
# This class implement a odbc connection. 
#
#

class Connection:
    def __init__(self, connectString = '', autocommit = False, ansi = False, timeout = 0, unicode_results = False, readonly = False, **kargs):
        """Init variables and connect to the engine"""
        self.connected = 0
        self.type_size_dic = {}
        self.ansi = False
        self.unicode_results = False
        self.dbc_h = ctypes.c_void_p()
        self.autocommit = autocommit
        self.readonly = False
        self.timeout = 0

        for key, value in list(kargs.items()):
            connectString = connectString + key + '=' + value + ';'
        self.connectString = connectString

        
        self.clear_output_converters()

        try:
            lock.acquire()
            if shared_env_h == None:
                #Initialize an enviroment if it is not created.
                AllocateEnv()
        finally:
            lock.release()
        
        # Allocate an DBC handle self.dbc_h under the environment shared_env_h
        # This DBC handle is actually the basis of a "connection"
        # The handle of self.dbc_h will be used to connect to a certain source 
        # in the self.connect and self.ConnectByDSN method
        
        ret = ODBC_API.SQLAllocHandle(SQL_HANDLE_DBC, shared_env_h, ADDR(self.dbc_h))
        check_success(self, ret)
        
        self.connect(connectString, autocommit, ansi, timeout, unicode_results, readonly)
        
            
     
    def connect(self, connectString = '', autocommit = False, ansi = False, timeout = 0, unicode_results = False, readonly = False):
        """Connect to odbc, using connect strings and set the connection's attributes like autocommit and timeout
        by calling SQLSetConnectAttr
        """ 

        # Before we establish the connection by the connection string
        # Set the connection's attribute of "timeout" (Actully LOGIN_TIMEOUT)
        if timeout != 0:
            ret = ODBC_API.SQLSetConnectAttr(self.dbc_h, SQL_ATTR_LOGIN_TIMEOUT, timeout, SQL_IS_UINTEGER);
            check_success(self, ret)


        # Create one connection with a connect string by calling SQLDriverConnect
        # and make self.dbc_h the handle of this connection


        # Convert the connetsytring to encoded string
        # so it can be converted to a ctypes c_char array object 

        
        self.ansi = ansi
        if not ansi:
            c_connectString = wchar_pointer(ucs2_buf(self.connectString))
            odbc_func = ODBC_API.SQLDriverConnectW
        else:
            c_connectString = ctypes.c_char_p(self.connectString)
            odbc_func = ODBC_API.SQLDriverConnect

        # With unixODBC, SQLDriverConnect will intermittently fail with error:
        #    [01000] [unixODBC][Driver Manager]Can't open lib '/path/to/so' : file not found"
        # or:
        #    [01000] [unixODBC][Driver Manager]Can't open lib '/path/to/so' : (null)"
        # when called concurrently by more than one threads. So, we have to
        # use a lock to serialize the calls. By the way, the error is much
        # less likely to happen if ODBC Tracing is enabled, likely due to the
        # implicit serialization caused by writing to trace file.
        if ODBC_API._name != 'odbc32':
            try:
                lock.acquire()
                ret = odbc_func(self.dbc_h, 0, c_connectString, len(self.connectString), None, 0, None, SQL_DRIVER_NOPROMPT)
            finally:
                lock.release()
        else:
            ret = odbc_func(self.dbc_h, 0, c_connectString, len(self.connectString), None, 0, None, SQL_DRIVER_NOPROMPT)
        check_success(self, ret)
            
        
        # Set the connection's attribute of "autocommit" 
        #
        self.autocommit = autocommit
        
        if self.autocommit == True:
            ret = ODBC_API.SQLSetConnectAttr(self.dbc_h, SQL_ATTR_AUTOCOMMIT, SQL_AUTOCOMMIT_ON, SQL_IS_UINTEGER)
        else:
            ret = ODBC_API.SQLSetConnectAttr(self.dbc_h, SQL_ATTR_AUTOCOMMIT, SQL_AUTOCOMMIT_OFF, SQL_IS_UINTEGER)
    
        check_success(self, ret)
       
        # Set the connection's attribute of "readonly" 
        #
        self.readonly = readonly
        
        ret = ODBC_API.SQLSetConnectAttr(self.dbc_h, SQL_ATTR_ACCESS_MODE, self.readonly and SQL_MODE_READ_ONLY or SQL_MODE_READ_WRITE, SQL_IS_UINTEGER)
        check_success(self, ret)
        
        self.unicode_results = unicode_results
        self.update_type_size_info()
        self.connected = 1
        
    def clear_output_converters(self):
        self.output_converter = {}
        for sqltype, profile in list(SQL_data_type_dict.items()):
            self.output_converter[sqltype] = profile[1]
        
        
    def add_output_converter(self, sqltype, func):
        self.output_converter[sqltype] = func
    
    def settimeout(self, timeout):
        ret = ODBC_API.SQLSetConnectAttr(self.dbc_h, SQL_ATTR_CONNECTION_TIMEOUT, timeout, SQL_IS_UINTEGER);
        check_success(self, ret)
        self.timeout = timeout
        

    def ConnectByDSN(self, dsn, user, passwd = ''):
        """Connect to odbc, we need dsn, user and optionally password"""
        self.dsn = dsn
        self.user = user
        self.passwd = passwd

        sn = create_buffer(dsn)
        un = create_buffer(user)        
        pw = create_buffer(passwd)
        
        ret = ODBC_API.SQLConnect(self.dbc_h, sn, len(sn), un, len(un), pw, len(pw))
        check_success(self, ret)

        self.update_type_size_info()
        self.connected = 1
        
        
    def cursor(self, row_type_callable=None): 
        #self.settimeout(self.timeout)
        if not self.connected:
            raise ProgrammingError('HY000','Attempt to use a closed connection.')
        
        
        return Cursor(self, row_type_callable=row_type_callable)   

    def update_type_size_info(self):
        for sql_type in (
            SQL_TYPE_TIMESTAMP,
            SQL_TYPE_DATE,
            SQL_TYPE_TIME,
            SQL_SS_TIME2,
        ):
            cur = Cursor(self)
            info_tuple = cur.getTypeInfo(sql_type)
            if info_tuple != None:
                self.type_size_dic[sql_type] = info_tuple[2], info_tuple[14]
            cur.close()

    
    def commit(self):
        if not self.connected:
            raise ProgrammingError('HY000','Attempt to use a closed connection.')
        
        ret = ODBC_API.SQLEndTran(SQL_HANDLE_DBC, self.dbc_h, SQL_COMMIT);
        check_success(self, ret)

    def rollback(self):
        if not self.connected:
            raise ProgrammingError('HY000','Attempt to use a closed connection.')
        
        ret = ODBC_API.SQLEndTran(SQL_HANDLE_DBC, self.dbc_h, SQL_ROLLBACK);
        check_success(self, ret)
        
    
    
    def getinfo(self,infotype):
        if infotype not in list(aInfoTypes.keys()):
            raise ProgrammingError('HY000','Invalid getinfo value: '+str(infotype)) 
        
        
        if aInfoTypes[infotype] == 'GI_UINTEGER':
            total_buf_len = 1000
            alloc_buffer = ctypes.c_ulong()
            used_buf_len = ctypes.c_short()
            ret = ODBC_API.SQLGetInfo(self.dbc_h,infotype,ADDR(alloc_buffer), total_buf_len,\
                    ADDR(used_buf_len))
            check_success(self, ret)
            result = alloc_buffer.value
            
        elif aInfoTypes[infotype] == 'GI_USMALLINT':
            total_buf_len = 1000
            alloc_buffer = ctypes.c_ushort()
            used_buf_len = ctypes.c_short()
            ret = ODBC_API.SQLGetInfo(self.dbc_h,infotype,ADDR(alloc_buffer), total_buf_len,\
                    ADDR(used_buf_len))
            check_success(self, ret)
            result = alloc_buffer.value

        else:
            total_buf_len = 1000
            alloc_buffer = create_buffer(total_buf_len)
            used_buf_len = ctypes.c_short()
            if self.ansi:
                API_f = ODBC_API.SQLGetInfo
            else:
                API_f = ODBC_API.SQLGetInfoW
            ret = API_f(self.dbc_h,infotype,ADDR(alloc_buffer), total_buf_len,\
                    ADDR(used_buf_len))
            check_success(self, ret)
            if self.ansi:
                result = alloc_buffer.value
            else:
                result = ucs2_dec(alloc_buffer)
            if aInfoTypes[infotype] == 'GI_YESNO':
                if unicode(result[0]) == unicode('Y'):
                    result = True
                else:
                    result = False
                    
        return result
        
    def __exit__(self, type, value, traceback):
        if value:
            self.rollback()
        else:
            self.commit()
            
        if self.connected:
            self.close()
            
    def __enter__(self):
        return self

    def __del__(self):
        if self.connected:
            self.close()
        
    def close(self):
        if not self.connected:
            raise ProgrammingError('HY000','Attempt to close a closed connection.')
        
        
        if self.connected:
            #if DEBUG:print 'disconnect'
            if not self.autocommit:
                self.rollback()
            ret = ODBC_API.SQLDisconnect(self.dbc_h)
            check_success(self, ret)
        #if DEBUG:print 'free dbc'
        ret = ODBC_API.SQLFreeHandle(SQL_HANDLE_DBC, self.dbc_h)
        check_success(self, ret)
#        if shared_env_h.value:
#            #if DEBUG:print 'env'
#            ret = ODBC_API.SQLFreeHandle(SQL_HANDLE_ENV, shared_env_h)
#            check_success(shared_env_h, ret)
        self.connected = 0
        
odbc = Connection
connect = odbc
'''
def connect(connectString = '', autocommit = False, ansi = False, timeout = 0, unicode_results = False, readonly = False, **kargs):
    return odbc(connectString, autocommit, ansi, timeout, unicode_results, readonly, kargs)
'''

def win_create_mdb(mdb_path, sort_order = "General\0\0"):
    if sys.platform not in ('win32','cli'):
        raise Exception('This function is available for use in Windows only.')
    #CREATE_DB=<path name> <sort order>
    ctypes.windll.ODBCCP32.SQLConfigDataSource.argtypes = [ctypes.c_void_p,ctypes.c_ushort,ctypes.c_char_p,ctypes.c_char_p]
    driver_name = "Microsoft Access Driver (*.mdb)"
    if py_v3:
        c_Path =  bytes("CREATE_DB=" + mdb_path + " " + sort_order,'mbcs')
        driver_name = bytes(driver_name,'mbcs')
    else:
        c_Path =  "CREATE_DB=" + mdb_path + " " + sort_order
    ODBC_ADD_SYS_DSN = 1
    ret = ctypes.windll.ODBCCP32.SQLConfigDataSource(None,ODBC_ADD_SYS_DSN,driver_name, c_Path)
    if not ret:
        raise Exception('Failed to create Access mdb file. Please check file path, permission and Access driver readiness.')
    

def win_compact_mdb(mdb_path, compacted_mdb_path, sort_order = "General\0\0"):
    if sys.platform not in ('win32','cli'):
        raise Exception('This function is available for use in Windows only.')
    #COMPACT_DB=<source path> <destination path> <sort order>
    ctypes.windll.ODBCCP32.SQLConfigDataSource.argtypes = [ctypes.c_void_p,ctypes.c_ushort,ctypes.c_char_p,ctypes.c_char_p]
    driver_name = "Microsoft Access Driver (*.mdb)"
    if py_v3:
        c_Path = bytes("COMPACT_DB=" + mdb_path + " " + compacted_mdb_path + " " + sort_order,'mbcs')
        driver_name = bytes(driver_name,'mbcs')
    else:
        c_Path = "COMPACT_DB=" + mdb_path + " " + compacted_mdb_path + " " + sort_order
    ODBC_ADD_SYS_DSN = 1
    ret = ctypes.windll.ODBCCP32.SQLConfigDataSource(None,ODBC_ADD_SYS_DSN,driver_name, c_Path)
    if not ret:
        raise Exception('Failed to compact Access mdb file. Please check file path, permission and Access driver readiness.')

def dataSources():
    """Return a list with [name, descrition]"""
    dsn = create_buffer(1024)
    desc = create_buffer(1024)
    dsn_len = ctypes.c_short()
    desc_len = ctypes.c_short()
    dsn_list = {}
    try:
        lock.acquire()
        if shared_env_h == None:
            AllocateEnv()
    finally:
        lock.release()
    while 1:
        ret = ODBC_API.SQLDataSources(shared_env_h, SQL_FETCH_NEXT, \
            dsn, len(dsn), ADDR(dsn_len), desc, len(desc), ADDR(desc_len))
        if ret == SQL_NO_DATA_FOUND:
            break
        elif not ret in (SQL_SUCCESS, SQL_SUCCESS_WITH_INFO):
            ctrl_err(SQL_HANDLE_ENV, shared_env_h, ret)
        else:
            dsn_list[dsn.value] = desc.value
    return dsn_list