How to use the satpy.imageo.formats.libtiff.TIFFDataType function in satpy

TIFF_LONG = 4
    TIFF_RATIONAL = 5
    TIFF_SBYTE = 6
    TIFF_UNDEFINED = 7
    TIFF_SSHORT = 8
    TIFF_SLONG = 9
    TIFF_SRATIONAL = 10
    TIFF_FLOAT = 11
    TIFF_DOUBLE = 12
    TIFF_IFD = 13

ttype2ctype = {
    TIFFDataType.TIFF_NOTYPE : None,
    TIFFDataType.TIFF_BYTE : ctypes.c_ubyte,
    TIFFDataType.TIFF_ASCII : ctypes.c_char_p,
    TIFFDataType.TIFF_SHORT : ctypes.c_uint16,
    TIFFDataType.TIFF_LONG : ctypes.c_uint32,
    TIFFDataType.TIFF_RATIONAL : ctypes.c_double, # Should be unsigned
    TIFFDataType.TIFF_SBYTE : ctypes.c_byte,
    TIFFDataType.TIFF_UNDEFINED : ctypes.c_char,
    TIFFDataType.TIFF_SSHORT : ctypes.c_int16,
    TIFFDataType.TIFF_SLONG : ctypes.c_int32,
    TIFFDataType.TIFF_SRATIONAL : ctypes.c_double,
    TIFFDataType.TIFF_FLOAT : ctypes.c_float,
    TIFFDataType.TIFF_DOUBLE : ctypes.c_double,
    TIFFDataType.TIFF_IFD : ctypes.c_uint32
    }

class TIFFFieldInfo(ctypes.Structure):
    """
    typedef struct {
        ttag_t  field_tag;      /* field's tag */

TIFF_DOUBLE = 12
    TIFF_IFD = 13

ttype2ctype = {
    TIFFDataType.TIFF_NOTYPE : None,
    TIFFDataType.TIFF_BYTE : ctypes.c_ubyte,
    TIFFDataType.TIFF_ASCII : ctypes.c_char_p,
    TIFFDataType.TIFF_SHORT : ctypes.c_uint16,
    TIFFDataType.TIFF_LONG : ctypes.c_uint32,
    TIFFDataType.TIFF_RATIONAL : ctypes.c_double, # Should be unsigned
    TIFFDataType.TIFF_SBYTE : ctypes.c_byte,
    TIFFDataType.TIFF_UNDEFINED : ctypes.c_char,
    TIFFDataType.TIFF_SSHORT : ctypes.c_int16,
    TIFFDataType.TIFF_SLONG : ctypes.c_int32,
    TIFFDataType.TIFF_SRATIONAL : ctypes.c_double,
    TIFFDataType.TIFF_FLOAT : ctypes.c_float,
    TIFFDataType.TIFF_DOUBLE : ctypes.c_double,
    TIFFDataType.TIFF_IFD : ctypes.c_uint32
    }

class TIFFFieldInfo(ctypes.Structure):
    """
    typedef struct {
        ttag_t  field_tag;      /* field's tag */
        short   field_readcount;    /* read count/TIFF_VARIABLE/TIFF_SPP */
        short   field_writecount;   /* write count/TIFF_VARIABLE */
        TIFFDataType field_type;    /* type of associated data */
        unsigned short field_bit;   /* bit in fieldsset bit vector */
        unsigned char field_oktochange; /* if true, can change while writing */
        unsigned char field_passcount;  /* if true, pass dir count on set */
        char    *field_name;        /* ASCII name */
        } TIFFFieldInfo;

TIFF_UNDEFINED = 7
    TIFF_SSHORT = 8
    TIFF_SLONG = 9
    TIFF_SRATIONAL = 10
    TIFF_FLOAT = 11
    TIFF_DOUBLE = 12
    TIFF_IFD = 13

ttype2ctype = {
    TIFFDataType.TIFF_NOTYPE : None,
    TIFFDataType.TIFF_BYTE : ctypes.c_ubyte,
    TIFFDataType.TIFF_ASCII : ctypes.c_char_p,
    TIFFDataType.TIFF_SHORT : ctypes.c_uint16,
    TIFFDataType.TIFF_LONG : ctypes.c_uint32,
    TIFFDataType.TIFF_RATIONAL : ctypes.c_double, # Should be unsigned
    TIFFDataType.TIFF_SBYTE : ctypes.c_byte,
    TIFFDataType.TIFF_UNDEFINED : ctypes.c_char,
    TIFFDataType.TIFF_SSHORT : ctypes.c_int16,
    TIFFDataType.TIFF_SLONG : ctypes.c_int32,
    TIFFDataType.TIFF_SRATIONAL : ctypes.c_double,
    TIFFDataType.TIFF_FLOAT : ctypes.c_float,
    TIFFDataType.TIFF_DOUBLE : ctypes.c_double,
    TIFFDataType.TIFF_IFD : ctypes.c_uint32
    }

class TIFFFieldInfo(ctypes.Structure):
    """
    typedef struct {
        ttag_t  field_tag;      /* field's tag */
        short   field_readcount;    /* read count/TIFF_VARIABLE/TIFF_SPP */
        short   field_writecount;   /* write count/TIFF_VARIABLE */
        TIFFDataType field_type;    /* type of associated data */

TIFF_IFD = 13

ttype2ctype = {
    TIFFDataType.TIFF_NOTYPE : None,
    TIFFDataType.TIFF_BYTE : ctypes.c_ubyte,
    TIFFDataType.TIFF_ASCII : ctypes.c_char_p,
    TIFFDataType.TIFF_SHORT : ctypes.c_uint16,
    TIFFDataType.TIFF_LONG : ctypes.c_uint32,
    TIFFDataType.TIFF_RATIONAL : ctypes.c_double, # Should be unsigned
    TIFFDataType.TIFF_SBYTE : ctypes.c_byte,
    TIFFDataType.TIFF_UNDEFINED : ctypes.c_char,
    TIFFDataType.TIFF_SSHORT : ctypes.c_int16,
    TIFFDataType.TIFF_SLONG : ctypes.c_int32,
    TIFFDataType.TIFF_SRATIONAL : ctypes.c_double,
    TIFFDataType.TIFF_FLOAT : ctypes.c_float,
    TIFFDataType.TIFF_DOUBLE : ctypes.c_double,
    TIFFDataType.TIFF_IFD : ctypes.c_uint32
    }

class TIFFFieldInfo(ctypes.Structure):
    """
    typedef struct {
        ttag_t  field_tag;      /* field's tag */
        short   field_readcount;    /* read count/TIFF_VARIABLE/TIFF_SPP */
        short   field_writecount;   /* write count/TIFF_VARIABLE */
        TIFFDataType field_type;    /* type of associated data */
        unsigned short field_bit;   /* bit in fieldsset bit vector */
        unsigned char field_oktochange; /* if true, can change while writing */
        unsigned char field_passcount;  /* if true, pass dir count on set */
        char    *field_name;        /* ASCII name */
        } TIFFFieldInfo;
    """

TIFF_SRATIONAL = 10
    TIFF_FLOAT = 11
    TIFF_DOUBLE = 12
    TIFF_IFD = 13

ttype2ctype = {
    TIFFDataType.TIFF_NOTYPE : None,
    TIFFDataType.TIFF_BYTE : ctypes.c_ubyte,
    TIFFDataType.TIFF_ASCII : ctypes.c_char_p,
    TIFFDataType.TIFF_SHORT : ctypes.c_uint16,
    TIFFDataType.TIFF_LONG : ctypes.c_uint32,
    TIFFDataType.TIFF_RATIONAL : ctypes.c_double, # Should be unsigned
    TIFFDataType.TIFF_SBYTE : ctypes.c_byte,
    TIFFDataType.TIFF_UNDEFINED : ctypes.c_char,
    TIFFDataType.TIFF_SSHORT : ctypes.c_int16,
    TIFFDataType.TIFF_SLONG : ctypes.c_int32,
    TIFFDataType.TIFF_SRATIONAL : ctypes.c_double,
    TIFFDataType.TIFF_FLOAT : ctypes.c_float,
    TIFFDataType.TIFF_DOUBLE : ctypes.c_double,
    TIFFDataType.TIFF_IFD : ctypes.c_uint32
    }

class TIFFFieldInfo(ctypes.Structure):
    """
    typedef struct {
        ttag_t  field_tag;      /* field's tag */
        short   field_readcount;    /* read count/TIFF_VARIABLE/TIFF_SPP */
        short   field_writecount;   /* write count/TIFF_VARIABLE */
        TIFFDataType field_type;    /* type of associated data */
        unsigned short field_bit;   /* bit in fieldsset bit vector */
        unsigned char field_oktochange; /* if true, can change while writing */
        unsigned char field_passcount;  /* if true, pass dir count on set */

TIFF_SBYTE = 6
    TIFF_UNDEFINED = 7
    TIFF_SSHORT = 8
    TIFF_SLONG = 9
    TIFF_SRATIONAL = 10
    TIFF_FLOAT = 11
    TIFF_DOUBLE = 12
    TIFF_IFD = 13

ttype2ctype = {
    TIFFDataType.TIFF_NOTYPE : None,
    TIFFDataType.TIFF_BYTE : ctypes.c_ubyte,
    TIFFDataType.TIFF_ASCII : ctypes.c_char_p,
    TIFFDataType.TIFF_SHORT : ctypes.c_uint16,
    TIFFDataType.TIFF_LONG : ctypes.c_uint32,
    TIFFDataType.TIFF_RATIONAL : ctypes.c_double, # Should be unsigned
    TIFFDataType.TIFF_SBYTE : ctypes.c_byte,
    TIFFDataType.TIFF_UNDEFINED : ctypes.c_char,
    TIFFDataType.TIFF_SSHORT : ctypes.c_int16,
    TIFFDataType.TIFF_SLONG : ctypes.c_int32,
    TIFFDataType.TIFF_SRATIONAL : ctypes.c_double,
    TIFFDataType.TIFF_FLOAT : ctypes.c_float,
    TIFFDataType.TIFF_DOUBLE : ctypes.c_double,
    TIFFDataType.TIFF_IFD : ctypes.c_uint32
    }

class TIFFFieldInfo(ctypes.Structure):
    """
    typedef struct {
        ttag_t  field_tag;      /* field's tag */
        short   field_readcount;    /* read count/TIFF_VARIABLE/TIFF_SPP */
        short   field_writecount;   /* write count/TIFF_VARIABLE */

TIFF_ASCII = 2
    TIFF_SHORT = 3
    TIFF_LONG = 4
    TIFF_RATIONAL = 5
    TIFF_SBYTE = 6
    TIFF_UNDEFINED = 7
    TIFF_SSHORT = 8
    TIFF_SLONG = 9
    TIFF_SRATIONAL = 10
    TIFF_FLOAT = 11
    TIFF_DOUBLE = 12
    TIFF_IFD = 13

ttype2ctype = {
    TIFFDataType.TIFF_NOTYPE : None,
    TIFFDataType.TIFF_BYTE : ctypes.c_ubyte,
    TIFFDataType.TIFF_ASCII : ctypes.c_char_p,
    TIFFDataType.TIFF_SHORT : ctypes.c_uint16,
    TIFFDataType.TIFF_LONG : ctypes.c_uint32,
    TIFFDataType.TIFF_RATIONAL : ctypes.c_double, # Should be unsigned
    TIFFDataType.TIFF_SBYTE : ctypes.c_byte,
    TIFFDataType.TIFF_UNDEFINED : ctypes.c_char,
    TIFFDataType.TIFF_SSHORT : ctypes.c_int16,
    TIFFDataType.TIFF_SLONG : ctypes.c_int32,
    TIFFDataType.TIFF_SRATIONAL : ctypes.c_double,
    TIFFDataType.TIFF_FLOAT : ctypes.c_float,
    TIFFDataType.TIFF_DOUBLE : ctypes.c_double,
    TIFFDataType.TIFF_IFD : ctypes.c_uint32
    }

class TIFFFieldInfo(ctypes.Structure):
    """

TIFFFieldInfo(NTD_MinGrayValue, 1, 1, TIFFDataType.TIFF_SLONG,
                      FIELD_CUSTOM, True, False, "MinGrayValue" ),
    NTD_MaxGrayValue:
        TIFFFieldInfo(NTD_MaxGrayValue, 1, 1, TIFFDataType.TIFF_SLONG,
                      FIELD_CUSTOM, True, False, "MaxGrayValue" ),
    NTD_Gradient:
        TIFFFieldInfo(NTD_Gradient, 1, 1, TIFFDataType.TIFF_FLOAT,
                      FIELD_CUSTOM, True, False, "Gradient" ),
    NTD_AxisIntercept:
        TIFFFieldInfo(NTD_AxisIntercept, 1, 1, TIFFDataType.TIFF_FLOAT,
                      FIELD_CUSTOM, True, False, "AxisIntercept" ),
    NTD_ColorTable:
        TIFFFieldInfo(NTD_ColorTable, -1, -1, TIFFDataType.TIFF_ASCII,
                      FIELD_CUSTOM, True, False, "ColorTable" ),
    NTD_Description:
        TIFFFieldInfo(NTD_Description, -1, -1, TIFFDataType.TIFF_ASCII,
                      FIELD_CUSTOM, True, False, "Description" ),
    NTD_OverflightDirection:
        TIFFFieldInfo(NTD_OverflightDirection, -1, -1, TIFFDataType.TIFF_ASCII,
                      FIELD_CUSTOM, True, False, "OverflightDirection" ),
    NTD_GeoLatitude:
        TIFFFieldInfo(NTD_GeoLatitude, 1, 1, TIFFDataType.TIFF_FLOAT,
                      FIELD_CUSTOM, True, False, "GeoLatitude" ),
    NTD_GeoLongitude:
        TIFFFieldInfo(NTD_GeoLongitude, 1, 1, TIFFDataType.TIFF_FLOAT,
                      FIELD_CUSTOM, True, False, "GeoLongitude" ),
    NTD_Altitude:
        TIFFFieldInfo(NTD_Altitude, 1, 1, TIFFDataType.TIFF_FLOAT,
                      FIELD_CUSTOM, True, False, "Altitude" ),
    NTD_AOSAsimuth:
        TIFFFieldInfo(NTD_AOSAsimuth, 1, 1, TIFFDataType.TIFF_FLOAT,
                      FIELD_CUSTOM, True, False, "AOSAsimuth" ),

tmp = a.GetField("LibtiffTestByte")
        assert tmp==42,"LibtiffTestbyte was not read as 42"
        tmp = a.GetField("LibtiffTestuint16")
        assert tmp==42,"LibtiffTestuint16 was not read as 42"
        tmp = a.GetField("LibtiffTestMultiuint32")
        assert tmp==[1,2,3,4,5,6,7,8,9,10],"LibtiffTestMultiuint32 was not read as [1,2,3,4,5,6,7,8,9,10]"
        tmp = a.GetField("LibtiffTeststr")
        assert tmp=="FAKE","LibtiffTeststr was not read as 'FAKE'"
        tmp = a.GetField("PRIMARYCHROMATICITIES")
        assert tmp==[1.0,2.0,3.0,4.0,5.0,6.0],"PrimaryChromaticities was not read as [1.0,2.0,3.0,4.0,5.0,6.0]"
        print "Tag Read: SUCCESS"

    # Define a C structure that says how each tag should be used
    test_tags = [
        TIFFFieldInfo(40100, 1, 1, TIFFDataType.TIFF_BYTE, FIELD_CUSTOM, True, False, "LibtiffTestByte"),
        TIFFFieldInfo(40103, 10, 10, TIFFDataType.TIFF_LONG, FIELD_CUSTOM, True, False, "LibtiffTestMultiuint32"),
        TIFFFieldInfo(40102, 1, 1, TIFFDataType.TIFF_SHORT, FIELD_CUSTOM, True, False, "LibtiffTestuint16"),
        TIFFFieldInfo(40101, -1, -1, TIFFDataType.TIFF_ASCII, FIELD_CUSTOM, True, False, "LibtiffTeststr")
        ]

    # Add tags to the libtiff library
    test_extender = add_tags(test_tags) # Keep pointer to extender object, no gc
    _tag_write()
    _tag_read()

TIFF_BYTE = 1
    TIFF_ASCII = 2
    TIFF_SHORT = 3
    TIFF_LONG = 4
    TIFF_RATIONAL = 5
    TIFF_SBYTE = 6
    TIFF_UNDEFINED = 7
    TIFF_SSHORT = 8
    TIFF_SLONG = 9
    TIFF_SRATIONAL = 10
    TIFF_FLOAT = 11
    TIFF_DOUBLE = 12
    TIFF_IFD = 13

ttype2ctype = {
    TIFFDataType.TIFF_NOTYPE : None,
    TIFFDataType.TIFF_BYTE : ctypes.c_ubyte,
    TIFFDataType.TIFF_ASCII : ctypes.c_char_p,
    TIFFDataType.TIFF_SHORT : ctypes.c_uint16,
    TIFFDataType.TIFF_LONG : ctypes.c_uint32,
    TIFFDataType.TIFF_RATIONAL : ctypes.c_double, # Should be unsigned
    TIFFDataType.TIFF_SBYTE : ctypes.c_byte,
    TIFFDataType.TIFF_UNDEFINED : ctypes.c_char,
    TIFFDataType.TIFF_SSHORT : ctypes.c_int16,
    TIFFDataType.TIFF_SLONG : ctypes.c_int32,
    TIFFDataType.TIFF_SRATIONAL : ctypes.c_double,
    TIFFDataType.TIFF_FLOAT : ctypes.c_float,
    TIFFDataType.TIFF_DOUBLE : ctypes.c_double,
    TIFFDataType.TIFF_IFD : ctypes.c_uint32
    }

class TIFFFieldInfo(ctypes.Structure):