GXBF class

class GXBF(handle=0)

GXBF class.

The GXBF class is used to access (or create) Binary files and remove (or destroy) files from use. You can also perform a variety of additional tasks, such as positioning within files, reading from files and writing to files.

__init__(handle=0)

ch_size(size)

Changes the size of a file

Parameters:

size (int) – New length in bytes

New in version 5.0.

License: Geosoft Open License

copy(b_fw)

Copy entire contents of a source GXBF to a destination GXBF

Parameters:

b_fw (GXBF) – Destination GXBF

New in version 5.0.

License: Geosoft Open License

crc(size, crc)

Compute CRC of a file.

Parameters:

• size (int) – Number of bytes to CRC

• crc (int) – CRC start (use CRC_INIT_VALUE for new)

Returns:

CRC Value

Return type:

int

New in version 5.0.

License: Geosoft Open License

classmethod create(file, status)

Create GXBF object.

Parameters:

• file (str) – File name to open (”” is a temporary file)

• status (int) – BF_OPEN_MODE constants

Returns:

GXBF Object

Return type:

GXBF

New in version 5.0.

License: Geosoft Open License

Note: Run-time specific directory paths may be added the the front of file names as follows:

<geosoft> the main Geosoft installation directory <geosoft2> the secondary Geosoft installation directory <geotemp> the Geosoft temporary file directory <windows> the operating system Windows directory <system> the operating system system directory <other> other environment variables

For example “<geosoft>/user/csv/datum.csv”

classmethod create_sbf(sbf, file, status)

Create GXBF object inside an GXSBF.

Parameters:

• sbf (GXSBF) – Storage

• file (str) – File name to open (”” is a temporary file)

• status (int) – BF_OPEN_MODE constants

Returns:

GXBF Object

Return type:

GXBF

New in version 5.0.

License: Geosoft Open License

Note: see sbf.gxh

eof()

Returns 1 if at the end of the file

Returns:

1 if at the end of the file, 0 if not at the end of the file

Return type:

int

New in version 5.0.

License: Geosoft Open License

is_null()

Check if this is a null (undefined) instance

Returns:

True if this is a null (undefined) instance, False otherwise.

Return type:

bool

classmethod null()

A null (undefined) instance of GXBF

Returns:

A null GXBF

Return type:

GXBF

query_write()

Check if you can write to the GXBF.

Returns:

0 - No 1 - Yes

Return type:

int

New in version 5.1.1.

License: Geosoft Open License

read_binary_string(bytes, encoding, data)

Reads string data from current position in GXBF

Parameters:

• bytes (int) – Number of bytes to read

• encoding (int) – BF_ENCODE constants

• data (str_ref) – Data

New in version 6.3.

License: Geosoft Open License

read_double(type, data)

Reads real data from current position in GXBF

Parameters:

• type (int) – GS_TYPES constants and BF_BYTEORDER constants

• data (float_ref) – Data

New in version 5.0.

License: Geosoft Open License

Note: If the data source may be in byte order different from that required by the reader, you can add the source byte-order to the GXBF elelment type. The byte order will be swapped if required. For example, to write out a real number 3.5 with Most-Significant_Byte first (Mortorola) convention:

write_double,3.5).

If a byte order is not specified, the source is assumed to be in the native byte order of the reading/writing computer.

read_int(type, data)

Reads int data from current position in GXBF

Parameters:

• type (int) – GS_TYPES constants and BF_BYTEORDER constants

• data (int_ref) – Data

New in version 5.0.

License: Geosoft Open License

Note: If the data source may be in byte order different from that required by the reader, you can add the source byte-order to the GXBF elelment type. The byte order will be swapped if required. For example, to write out a real number 3.5 with Most-Significant_Byte first (Mortorola) convention:

write_double,3.5).

If a byte order is not specified, the source is assumed to be in the native byte order of the reading/writing computer.

read_vv(type, vv)

Read data to a GXVV from current position in GXBF

Parameters:

• type (int) – GS_TYPES constants and BF_BYTEORDER constants

• vv (GXVV) – GXVV data to read, GXVV length is read

New in version 5.0.

License: Geosoft Open License

Note: If the data source may be in byte order different from that required by the reader, you can add the source byte-order to the GXBF elelment type. The byte order will be swapped if required. For example, to write out a real number 3.5 with Most-Significant_Byte first (Mortorola) convention:

write_double,3.5).

If a byte order is not specified, the source is assumed to be in the native byte order of the reading/writing computer.

seek(offset, ref)

Moves file position

Parameters:

• offset (int) – Number of bytes from reference point

• ref (int) – BF_SEEK constants

New in version 5.0.

License: Geosoft Open License

Note: Terminates if attempt to move past the end of a read-only file.

set_destroy_status(status)

Set the flag to delete the file on close

Parameters:

status (int) – BF_CLOSE constants

New in version 6.0.

License: Geosoft Open License

size()

Returns the file length

Returns:

File size in bytes.

Return type:

int

New in version 5.0.

License: Geosoft Open License

tell()

Returns current position of file pointer in bytes

Returns:

Current file pointer location

Return type:

int

New in version 5.0.

License: Geosoft Open License

write_binary_string(encoding, data)

Write a binary string to a GXBF

Parameters:

• encoding (int) – BF_ENCODE constants

• data (str) – String to write out

New in version 6.3.

License: Geosoft Open License

write_data_null()

Writes a null byte (0) to GXBF

New in version 5.0.

License: Geosoft Open License

write_double(type, data)

Writes real to the GXBF

Parameters:

• type (int) – GS_TYPES constants and BF_BYTEORDER constants

• data (float) – Data

New in version 5.0.

License: Geosoft Open License

Note: See comments on byte order for the Read.. functions if you want to enforce a certain byte order.

If a byte order is not specified, the data is written in the native byte order of the writing computer.

write_int(type, data)

Writes int to the GXBF

Parameters:

• type (int) – GS_TYPES constants and BF_BYTEORDER constants

• data (int) – Data

New in version 5.0.

License: Geosoft Open License

Note: See comments on byte order for the Read.. functions if you want to enforce a certain byte order.

If a byte order is not specified, the data is written in the native byte order of the writing computer.

write_vv(type, vv)

Writes GXVV to the GXBF

Parameters:

• type (int) – GS_TYPES constants and BF_BYTEORDER constants

• vv (GXVV) – Data

New in version 5.0.

License: Geosoft Open License

Note: See comments on byte order for the Read.. functions if you want to enforce a certain byte order.

If a byte order is not specified, the data is written in the native byte order of the writing computer.

BF_BYTEORDER constants

Byte order for read/write

BF_BYTEORDER_LSB

Least significant byte first (Intel, Windows)

gxapi.BF_BYTEORDER_LSB = 256

BF_BYTEORDER_MSB

Most significant byte first (Mororola, Sun)

gxapi.BF_BYTEORDER_MSB = 512

BF_CLOSE constants

Close Flags

BF_KEEP

Bf keep

gxapi.BF_KEEP = 0

BF_DELETE

Bf delete

gxapi.BF_DELETE = 1

BF_ENCODE constants

The way a string is encoded

BF_ENCODE_ANSI

String is stored as ANSI code page

gxapi.BF_ENCODE_ANSI = 0

BF_ENCODE_UTF8

String is stored as UTF8 constants

gxapi.BF_ENCODE_UTF8 = 1

BF_OPEN_MODE constants

Open Status

BF_READ

Read only

gxapi.BF_READ = 0

BF_READWRITE_NEW

Erases existing file

gxapi.BF_READWRITE_NEW = 1

BF_READWRITE_OLD

File must pre-exist

gxapi.BF_READWRITE_OLD = 2

BF_READWRITE_APP

Open and append onto pre-existing file (cannot be read from)

gxapi.BF_READWRITE_APP = 4

BF_SEEK constants

Seek Location

BF_SEEK_START

Start

gxapi.BF_SEEK_START = 0

BF_SEEK_CURRENT

Current

gxapi.BF_SEEK_CURRENT = 1

BF_SEEK_EOF

Eof

gxapi.BF_SEEK_EOF = 2