blob: 7726f22ec8c5630b2c435a3e02c3c4cf66fee87a (
plain)
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
|
FIXED ARRAY
-----------
A fixed array looks like this:
typedef struct {
long s[4];
} Struct1;
the NDR representation looks just like 4 separate long
declarations. The array size is not encoded on the wire.
CONFORMANT ARRAYS
-----------------
A conformant array is one with that ends in [*] or []. The strange
things about conformant arrays are:
* they can only appear as the last element of a structure
* the array size appears before the structure itself on the wire.
So, in this example:
typedef struct {
long abc;
long count;
long foo;
[size_is(count)] long s[*];
} Struct1;
it appears like this:
[size_is] [abc] [count] [foo] [s...]
the first [size_is] field is the allocation size of the array, and
occurs before the array elements and even before the structure
alignment.
Note that size_is() can refer to a constant, but that doesn't change
the wire representation. It does not make the array a fixed array.
midl.exe would write the above array as the following C header:
typedef struct {
long abc;
long count;
long foo;
long s[1];
} Struct1;
VARYING ARRAYS
--------------
A varying array looks like this:
typedef struct {
long abc;
long count;
long foo;
[size_is(count)] long *s;
} Struct1;
This will look like this on the wire:
[abc] [count] [foo] [PTR_s] [count] [s...]
VALIDATOR
---------
We need to write an IDL validator, so we know that we are writing
valid IDL. Right now the compiler sails on regardless in many cases
even if the IDL is invalid (for example, I don't check that conformant
arrays are always the last element in any structure). There are dozens
of rules that should be checked.
|
