c++ - Mapping byte array data to structs in C# -

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i've been wrestling problem many hours turn here see if has idea how solve problem. have legacy c++ program sends packets via sockets. these contain c++ structs, thought easy define struct looking 1 in c++ in c# application , read byte array. i've noticed it's not simple , think i've boiled down problem alignment, still can't head round it.

my c++ struct looks this:

typedef struct {     int                  int_1;     short              short_1;     long               long_1;     char                char_11[11];     long               long_2;     short              short_2;     int                  int_2;  } test_klient_rec, *ptest_klient_rec;

which thought translate c# struct this:

[structlayout(layoutkind.explicit, pack=0)]     public struct test_klient_rec         {             [fieldoffset(0)]             [marshalas(unmanagedtype.i4)]             public int          int_1;          // 4             [fieldoffset(4)]             [marshalas(unmanagedtype.i2)]             public short        short_1;        // 2             [fieldoffset(6)]             [marshalas(unmanagedtype.i4)]             public int          long_1;         // 4             [fieldoffset(12)]             [marshalas(unmanagedtype.byvaltstr, sizeconst=11)]             public string       char_11;        // 11             [fieldoffset(22)]             [marshalas(unmanagedtype.i4)]             public int          long_2;         // 4             [fieldoffset(26)]             [marshalas(unmanagedtype.i2)]             public short        short_2;        // 2             [fieldoffset(28)]             [marshalas(unmanagedtype.i4)]             public int          int_2;          // 4         }

the problem seems how c# maps short (putting in padding of 2 bytes?) causes rest of struct badly aligned , creating garbage data. possible make work in way? i'm not fuzzed using structs in c# if classes makes easier.

the result of when using test data seems int_1, long_1 , short_1 correct values , else garbage, that's why suspect short problem here.

any thoughts more welcomed.

/j

edit: why have 12 instead of 10 string offset because seems char ararys have start @ dword, if put 10 instead think should (i know math thank you) crash "could not load type 'test_klient_rec' assembly 'socketandstructtest, version=1.0.0.0, culture=neutral, publickeytoken=null' because contains object field @ offset 10 incorrectly aligned or overlapped non-object field."

your fieldoffsets don't line way you'd expect. example, after 2 i_4's , i_2, have fieldoffset(12), whereas think you'd want fieldoffset(10).

also, think need apply [structlayout(layoutkind.explicit)] struct.


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