Source code for pygrass.raster.buffer

from grass.pygrass.raster.raster_type import TYPE as RTYPE
import ctypes
import numpy as np


_CELL = ("int", "intp", "int8", "int16", "int32", "int64")
CELL = tuple([getattr(np, attr) for attr in _CELL if hasattr(np, attr)])
_FCELL = "float", "float16", "float32"
FCELL = tuple([getattr(np, attr) for attr in _FCELL if hasattr(np, attr)])
_DCELL = "float64", "float128"
DCELL = tuple([getattr(np, attr) for attr in _DCELL if hasattr(np, attr)])


class Buffer(np.ndarray):
    """shape, mtype='FCELL', buffer=None, offset=0,
    strides=None, order=None
    """

    @property
    def mtype(self):
        if self.dtype in CELL:
            return "CELL"
        elif self.dtype in FCELL:
            return "FCELL"
        elif self.dtype in DCELL:
            return DCELL
        else:
            err = "Raster type: %r not supported by GRASS."
            raise TypeError(err % self.dtype)

    def __new__(
        cls, shape, mtype="FCELL", buffer=None, offset=0, strides=None, order=None
    ):
        obj = np.ndarray.__new__(
            cls, shape, RTYPE[mtype]["numpy"], buffer, offset, strides, order
        )
        obj.pointer_type = ctypes.POINTER(RTYPE[mtype]["ctypes"])
        obj.p = obj.ctypes.data_as(obj.pointer_type)
        return obj

    def __array_finalize__(self, obj):
        if obj is None:
            return
        self.pointer_type = getattr(obj, "pointer_type", None)
        self.p = getattr(obj, "p", None)

    def __array_wrap__(self, out_arr, context=None):
        """See:
        http://docs.scipy.org/doc/numpy/user/
        basics.subclassing.html#array-wrap-for-ufuncs"""
        if out_arr.dtype == bool:
            # there is not support for boolean maps, so convert into integer
            out_arr = out_arr.astype(np.int32)
        out_arr.p = out_arr.ctypes.data_as(out_arr.pointer_type)
        return np.ndarray.__array_wrap__(self, out_arr, context)