"""
PostGIS to GDAL conversion constant definitions
"""
# Lookup to convert pixel type values from GDAL to PostGIS
GDAL_TO_POSTGIS = [None, 4, 6, 5, 8, 7, 10, 11, None, None, None, None]
# Lookup to convert pixel type values from PostGIS to GDAL
POSTGIS_TO_GDAL = [1, 1, 1, 3, 1, 3, 2, 5, 4, None, 6, 7, None, None]
# Struct pack structure for raster header, the raster header has the
# following structure:
#
# Endianness, PostGIS raster version, number of bands, scale, origin,
# skew, srid, width, and height.
#
# Scale, origin, and skew have x and y values. PostGIS currently uses
# a fixed endianness (1) and there is only one version (0).
POSTGIS_HEADER_STRUCTURE = 'B H H d d d d d d i H H'
# Lookup values to convert GDAL pixel types to struct characters. This is
# used to pack and unpack the pixel values of PostGIS raster bands.
GDAL_TO_STRUCT = [
None, 'B', 'H', 'h', 'L', 'l', 'f', 'd',
None, None, None, None,
]
# Size of the packed value in bytes for different numerical types.
# This is needed to cut chunks of band data out of PostGIS raster strings
# when decomposing them into GDALRasters.
# See https://docs.python.org/3/library/struct.html#format-characters
STRUCT_SIZE = {
'b': 1, # Signed char
'B': 1, # Unsigned char
'?': 1, # _Bool
'h': 2, # Short
'H': 2, # Unsigned short
'i': 4, # Integer
'I': 4, # Unsigned Integer
'l': 4, # Long
'L': 4, # Unsigned Long
'f': 4, # Float
'd': 8, # Double
}