1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
"""
Error checking functions for GEOS ctypes prototype functions.
"""
from ctypes import c_void_p, string_at
from django.contrib.gis.geos.error import GEOSException
from django.contrib.gis.geos.libgeos import GEOSFuncFactory
# Getting the `free` routine used to free the memory allocated for
# string pointers returned by GEOS.
free = GEOSFuncFactory("GEOSFree")
free.argtypes = [c_void_p]
def last_arg_byref(args):
"Return the last C argument's value by reference."
return args[-1]._obj.value
def check_dbl(result, func, cargs):
"""
Check the status code and returns the double value passed in by reference.
"""
# Checking the status code
if result != 1:
return None
# Double passed in by reference, return its value.
return last_arg_byref(cargs)
def check_geom(result, func, cargs):
"Error checking on routines that return Geometries."
if not result:
raise GEOSException(
'Error encountered checking Geometry returned from GEOS C function "%s".'
% func.__name__
)
return result
def check_minus_one(result, func, cargs):
"Error checking on routines that should not return -1."
if result == -1:
raise GEOSException(
'Error encountered in GEOS C function "%s".' % func.__name__
)
else:
return result
def check_predicate(result, func, cargs):
"Error checking for unary/binary predicate functions."
if result == 1:
return True
elif result == 0:
return False
else:
raise GEOSException(
'Error encountered on GEOS C predicate function "%s".' % func.__name__
)
def check_sized_string(result, func, cargs):
"""
Error checking for routines that return explicitly sized strings.
This frees the memory allocated by GEOS at the result pointer.
"""
if not result:
raise GEOSException(
'Invalid string pointer returned by GEOS C function "%s"' % func.__name__
)
# A c_size_t object is passed in by reference for the second
# argument on these routines, and its needed to determine the
# correct size.
s = string_at(result, last_arg_byref(cargs))
# Freeing the memory allocated within GEOS
free(result)
return s
def check_string(result, func, cargs):
"""
Error checking for routines that return strings.
This frees the memory allocated by GEOS at the result pointer.
"""
if not result:
raise GEOSException(
'Error encountered checking string return value in GEOS C function "%s".'
% func.__name__
)
# Getting the string value at the pointer address.
s = string_at(result)
# Freeing the memory allocated within GEOS
free(result)
return s
|
