266 lines
6.7 KiB
Python
266 lines
6.7 KiB
Python
"""Low-level wrapper around zbar's interface
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"""
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from ctypes import (
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c_ubyte, c_char_p, c_int, c_uint, c_ulong, c_void_p, Structure,
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CFUNCTYPE, POINTER
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)
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from enum import IntEnum, unique
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from . import zbar_library
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__all__ = [
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'EXTERNAL_DEPENDENCIES', 'LIBZBAR', 'ZBarConfig', 'ZBarSymbol',
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'zbar_image_create', 'zbar_image_destroy', 'zbar_image_first_symbol',
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'zbar_image_scanner_create', 'zbar_image_scanner_destroy',
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'zbar_image_scanner_set_config', 'zbar_image_set_data',
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'zbar_image_set_format', 'zbar_image_set_size', 'zbar_scan_image',
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'zbar_symbol_get_data', 'zbar_symbol_get_loc_size',
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'zbar_symbol_get_loc_x', 'zbar_symbol_get_loc_y', 'zbar_symbol_next'
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]
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# Globals populated in load_libzbar
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LIBZBAR = None
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"""ctypes.CDLL
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"""
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EXTERNAL_DEPENDENCIES = []
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"""List of instances of ctypes.CDLL. Helpful when freezing.
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"""
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# Types
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c_ubyte_p = POINTER(c_ubyte)
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c_uint_p = POINTER(c_uint)
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c_ulong_p = POINTER(c_ulong)
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"""unsigned char* type
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"""
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# Defines and enums
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@unique
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class ZBarSymbol(IntEnum):
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NONE = 0 # /**< no symbol decoded */
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PARTIAL = 1 # /**< intermediate status */
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EAN2 = 2 # /**< GS1 2-digit add-on */
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EAN5 = 5 # /**< GS1 5-digit add-on */
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EAN8 = 8 # /**< EAN-8 */
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UPCE = 9 # /**< UPC-E */
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ISBN10 = 10 # /**< ISBN-10 (from EAN-13). @since 0.4 */
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UPCA = 12 # /**< UPC-A */
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EAN13 = 13 # /**< EAN-13 */
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ISBN13 = 14 # /**< ISBN-13 (from EAN-13). @since 0.4 */
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COMPOSITE = 15 # /**< EAN/UPC composite */
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I25 = 25 # /**< Interleaved 2 of 5. @since 0.4 */
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DATABAR = 34 # /**< GS1 DataBar (RSS). @since 0.11 */
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DATABAR_EXP = 35 # /**< GS1 DataBar Expanded. @since 0.11 */
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CODABAR = 38 # /**< Codabar. @since 0.11 */
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CODE39 = 39 # /**< Code 39. @since 0.4 */
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PDF417 = 57 # /**< PDF417. @since 0.6 */
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QRCODE = 64 # /**< QR Code. @since 0.10 */
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CODE93 = 93 # /**< Code 93. @since 0.11 */
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CODE128 = 128 # /**< Code 128 */
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@unique
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class ZBarConfig(IntEnum):
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CFG_ENABLE = 0 # /**< enable symbology/feature */
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CFG_ADD_CHECK = 1 # /**< enable check digit when optional */
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CFG_EMIT_CHECK = 2 # /**< return check digit when present */
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CFG_ASCII = 3 # /**< enable full ASCII character set */
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CFG_NUM = 4 # /**< number of boolean decoder configs */
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CFG_MIN_LEN = 0x20 # /**< minimum data length for valid decode */
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CFG_MAX_LEN = 0x21 # /**< maximum data length for valid decode */
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CFG_UNCERTAINTY = 0x40 # /**< required video consistency frames */
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CFG_POSITION = 0x80 # /**< enable scanner to collect position data */
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CFG_X_DENSITY = 0x100 # /**< image scanner vertical scan density */
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CFG_Y_DENSITY = 0x101 # /**< image scanner horizontal scan density */
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# Structs
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class zbar_image_scanner(Structure):
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"""Opaque C++ class with private implementation
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"""
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pass
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class zbar_image(Structure):
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"""Opaque C++ class with private implementation
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"""
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pass
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class zbar_symbol(Structure):
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"""Opaque C++ class with private implementation
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The first item in the structure is an integeger value in the ZBarSymbol
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enumeration.
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"""
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_fields_ = [
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('type', c_int),
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]
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def load_libzbar():
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"""Loads the zbar shared library and its dependencies.
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Populates the globals LIBZBAR and EXTERNAL_DEPENDENCIES.
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"""
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global LIBZBAR
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global EXTERNAL_DEPENDENCIES
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if not LIBZBAR:
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libzbar, dependencies = zbar_library.load()
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LIBZBAR = libzbar
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EXTERNAL_DEPENDENCIES = [LIBZBAR] + dependencies
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return LIBZBAR
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# Function signatures
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def zbar_function(fname, restype, *args):
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"""Returns a foreign function exported by `zbar`.
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Args:
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fname (:obj:`str`): Name of the exported function as string.
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restype (:obj:): Return type - one of the `ctypes` primitive C data
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types.
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*args: Arguments - a sequence of `ctypes` primitive C data types.
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Returns:
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cddl.CFunctionType: A wrapper around the function.
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"""
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prototype = CFUNCTYPE(restype, *args)
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return prototype((fname, load_libzbar()))
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zbar_version = zbar_function(
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'zbar_version',
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c_int,
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c_uint_p, # major,
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c_uint_p, # minor
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)
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zbar_set_verbosity = zbar_function(
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'zbar_set_verbosity',
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None,
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c_int
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)
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zbar_image_scanner_create = zbar_function(
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'zbar_image_scanner_create',
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POINTER(zbar_image_scanner)
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)
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zbar_image_scanner_destroy = zbar_function(
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'zbar_image_scanner_destroy',
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None,
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POINTER(zbar_image_scanner)
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)
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zbar_parse_config = zbar_function(
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'zbar_parse_config',
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c_int,
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c_char_p, # config_string,
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POINTER(c_int), # symbology - values in ZBarSymbol
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POINTER(c_int), # config - values in ZBarConfig
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POINTER(c_int), # value
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)
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zbar_image_scanner_set_config = zbar_function(
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'zbar_image_scanner_set_config',
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c_int,
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POINTER(zbar_image_scanner), # scanner
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c_int, # symbology - values in ZBarSymbol
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c_int, # config - values in ZBarConfig
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c_int # value
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)
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zbar_image_create = zbar_function(
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'zbar_image_create',
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POINTER(zbar_image)
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)
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zbar_image_destroy = zbar_function(
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'zbar_image_destroy',
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None,
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POINTER(zbar_image)
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)
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zbar_image_set_format = zbar_function(
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'zbar_image_set_format',
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None,
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POINTER(zbar_image),
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c_uint
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)
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zbar_image_set_size = zbar_function(
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'zbar_image_set_size',
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None,
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POINTER(zbar_image),
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c_uint, # width
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c_uint # height
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)
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zbar_image_set_data = zbar_function(
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'zbar_image_set_data',
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None,
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POINTER(zbar_image),
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c_void_p, # data
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c_ulong, # raw_image_data_length
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c_void_p # A function pointer(!)
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)
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zbar_scan_image = zbar_function(
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'zbar_scan_image',
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c_int,
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POINTER(zbar_image_scanner),
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POINTER(zbar_image)
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)
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zbar_image_first_symbol = zbar_function(
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'zbar_image_first_symbol',
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POINTER(zbar_symbol),
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POINTER(zbar_image)
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)
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zbar_symbol_get_data_length = zbar_function(
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'zbar_symbol_get_data_length',
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c_uint,
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POINTER(zbar_symbol)
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)
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zbar_symbol_get_data = zbar_function(
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'zbar_symbol_get_data',
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c_char_p,
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POINTER(zbar_symbol)
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)
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zbar_symbol_get_loc_size = zbar_function(
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'zbar_symbol_get_loc_size',
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c_uint,
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POINTER(zbar_symbol)
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)
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zbar_symbol_get_loc_x = zbar_function(
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'zbar_symbol_get_loc_x',
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c_int,
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POINTER(zbar_symbol),
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c_uint
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)
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zbar_symbol_get_loc_y = zbar_function(
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'zbar_symbol_get_loc_y',
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c_int,
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POINTER(zbar_symbol),
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c_uint
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)
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zbar_symbol_next = zbar_function(
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'zbar_symbol_next',
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POINTER(zbar_symbol),
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POINTER(zbar_symbol)
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)
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