Problem with calling DLL functions to return structure pointers

[kraotn]

Hello, everyone. I'm very sorry. My mother tongue is not English. I asked questions through machine translation

This is a function from the XXHASH library, derived from https://github.com/Cyan4973/xxHash/

I generated xxhash.dll using VS2022 and tested the DLL function in other languages to be normal. It is now converted to an AUTOIT call exception. May I ask why?

 

#cs

typedef uint64_t XXH64_hash_t;
typedef uint32_t XXH32_hash_t;

struct XXH64_state_s {
   XXH64_hash_t total_len;    /*!< Total length hashed. This is always 64-bit. */
   XXH64_hash_t v[4];         /*!< Accumulator lanes */
   XXH64_hash_t mem64[4];     /*!< Internal buffer for partial reads. Treated as unsigned char[32]. */
   XXH32_hash_t memsize;      /*!< Amount of data in @ref mem64 */
   XXH32_hash_t reserved32;   /*!< Reserved field, needed for padding anyways*/
   XXH64_hash_t reserved64;   /*!< Reserved field. Do not read or write to it, it may be removed. */
};   

typedef struct XXH64_state_s XXH64_state_t;  

XXH_PUBLIC_API XXH64_state_t* XXH64_createState(void)
{
    return (XXH64_state_t*)XXH_malloc(sizeof(XXH64_state_t));
}

#ce

#include <StructureConstants.au3>
#include <Memory.au3>

Global $XXH64_STATE_T  = "uint64 total_len; uint64 v[4]; uint64 mem64[4]; uint32 memsize; uint32 reserved32; uint64 reserved64;"

Func XXH64_createState()
    Local $pState = DllStructCreate($XXH64_STATE_T)
    Local $pResultPtr = DllCall("xxhash.dll", "ptr", "XXH64_createState")

    If @error Then Return $pState

    $pState = Ptr($pResultPtr[0])
    
    _MemGlobalAlloc(DllStructGetSize($pState))
    DllCall("kernel32.dll", "ptr", "CopyMemory", "ptr", $pState, "ptr", Ptr($pResultPtr[0]), "uint", DllStructGetSize($pState))
    ConsoleWrite("pResult[0]: " & $pState & ", total_len: " & DllStructGetData($pState, "total_len") & ", v[0]: " & DllStructGetData($pState, "v", 1) & ", v[1]: " & DllStructGetData($pState, "v", 2) & ", ..." & @CRLF)

    Return $pState
EndFunc
      

Local $pState = XXH64_createState()
 

 

 

[Danp2]

What is the definition of XXH_PUBLIC_API?

Hint: the following is from the help file --

Quote

By default, AutoIt uses the 'stdcall' calling method. To use the 'cdecl' method place ':cdecl' after the return type.
DllCall("SQLite.dll", "int:cdecl", "sqlite3_open", "str", $sDatabase_Filename , "long*", 0).

 

[kraotn]

#if (defined(XXH_INLINE_ALL) || defined(XXH_PRIVATE_API)) \
    && !defined(XXH_INLINE_ALL_31684351384)
   /* this section should be traversed only once */
#  define XXH_INLINE_ALL_31684351384
   /* give access to the advanced API, required to compile implementations */
#  undef XXH_STATIC_LINKING_ONLY   /* avoid macro redef */
#  define XXH_STATIC_LINKING_ONLY
   /* make all functions private */
#  undef XXH_PUBLIC_API
#  if defined(__GNUC__)
#    define XXH_PUBLIC_API static __inline __attribute__((unused))
#  elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
#    define XXH_PUBLIC_API static inline
#  elif defined(_MSC_VER)
#    define XXH_PUBLIC_API static __inline
#  else
     /* note: this version may generate warnings for unused static functions */
#    define XXH_PUBLIC_API static
#  endif
 

[Danp2]

You could try adding cdecl to the DllCall to see if that resolves your issue --

Local $pResultPtr = DllCall("xxhash.dll", "ptr:cdecl", "XXH64_createState")

FWIW, You haven't really told us what isn't working as expected.

[kraotn]

If the structure pointer returns normal, then the value of the structure variable should not be 0

 

#include <StructureConstants.au3>
#include <Memory.au3>

Global $XXH64_STATE_T  = "uint64 total_len; uint64 v[4]; uint64 mem64[4]; uint32 memsize; uint32 reserved32; uint64 reserved64;"

Func XXH64_createState()
    Local $pResultPtr = DllCall("xxhash.dll", "ptr:cdecl", "XXH64_createState")
    Local $pState = Ptr($pResultPtr[0])

    If @error Then Return $pState

    _MemGlobalAlloc(DllStructGetSize($pState))
    DllCall("kernel32.dll", "ptr", "CopyMemory", "ptr", $pState, "ptr", $pResultPtr[0], "uint", DllStructGetSize($pState))
;~    ConsoleWrite("pResult[0]: " & $pState & ", total_len: " & DllStructGetData($pState, "total_len") & ", v[0]: " & DllStructGetData($pState, "v", 1) & ", v[1]: " & DllStructGetData($pState, "v", 2) & ", ..." & @CRLF)
ConsoleWrite("pResult[0]: " & $pState & "total_len: " & DllStructGetData($pState, "total_len") & ", v[0]: " & DllStructGetData($pState, "v", 1) & ", v[1]: " & DllStructGetData($pState, "v", 2) & ", ..." & @CRLF)
    Return $pState
EndFunc

Local $pState = XXH64_createState()
 

 

 

The result of the code output now is: pResult[0]: 0x00000197D7CBA170total_len: 0, v[0]: 0, v[1]: 0, ...

[Danp2]

Did adding the "cdecl" help? If so, then I suspect that the issue is now in the code following the DllCall command. See if this works any better --

#include <StructureConstants.au3>
#include <Memory.au3>

Global $XXH64_STATE_T  = "uint64 total_len; uint64 v[4]; uint64 mem64[4]; uint32 memsize; uint32 reserved32; uint64 reserved64;"

Local $pState = XXH64_createState()

Func XXH64_createState()
    Local $pResult = DllCall("xxhash.dll", "ptr:cdecl", "XXH64_createState")

    Local $tStruct = DllStructCreate($XXH64_STATE_T, $pResult[0])
    
    ConsoleWrite("$pResult[0]: " & $pResult[0] & ", total_len: " & DllStructGetData($tStruct, "total_len") & ", v[0]: " & DllStructGetData($tStruct, "v", 1) & ", v[1]: " & DllStructGetData($tStruct, "v", 2) & ", ..." & @CRLF)
    Return $pResult[0]
EndFunc

 

[RTFC]

Had a quick look at the code; it's definitely cdecl calling convention, and since the call returns a 64-bit ptr, you'll want to run AutoIt in x64 mode.

[kraotn]

It runs under X64, but the output result is unstable, and the value of 0 is often obtained. It is normal to call it in C

 

 

#include <StructureConstants.au3>
#include <Memory.au3>

Global $XXH64_STATE_T  = "uint64 total_len; uint64 v[4]; uint64 mem64[4]; uint memsize; uint reserved32; uint64 reserved64;"

Local $pState = XXH64_createState()

Func XXH64_createState()
    Local $pResult = DllCall("xxhash.dll", "ptr:cdecl", "XXH64_createState")

    Local $tStruct = DllStructCreate($XXH64_STATE_T, $pResult[0])
    ConsoleWrite("$tStruct size: " & DllStructGetSize($tStruct) &@CRLF)
    ConsoleWrite("$pResult[0]: " & $pResult[0] & ", total_len: " & DllStructGetData($tStruct, "total_len") & ", v[0]: " & DllStructGetData($tStruct, "v", 1) & ", v[1]: " & DllStructGetData($tStruct, "v", 2) & ", ..." & @CRLF)
    Return $pResult[0]
EndFunc

 

xxhash.zip

[Danyfirex]

are you sure XXH64_createState->total_len should return a value? can you share a C++ example? I think issue could be due to the way compiler handle structure(while returning)

So probably You need to create a wrapper function for XXH64_createStateWrapper( *struct) and pass the AutoIt structure. so you could later do memcpy to copy XXH64_createState returned structure to your AutoIt structure.

It's just a mind I had being long time without touching C/C++.

 

Saludos

[kraotn]

#define BUFFER_SIZE 1024*64

uint64_t xxhsum_stream(FILE* fp) {
    
    XXH64_state_t* const state = XXH64_createState();
    printf("%llu %llu %llu %u %u %llu\n", state->total_len, state->v[0], state->mem64[0], state->memsize, state->reserved32, state->reserved64);

    XXH64_reset(state, 0);
    uint8_t buffer[BUFFER_SIZE];
    size_t read_size;
    while ((read_size = fread(buffer, 1, BUFFER_SIZE, fp)) != 0) {
        XXH64_update(state, buffer, read_size);
    }
    return XXH64_digest(state);
}

 

Please refer to the following address for the detailed function structure. Thank you very much

https://github.com/Cyan4973/xxHash/

Edited May 10, 2023 by kraotn

[footswitch]

Hi @kraotn, where did you get the dll? Did you compile it yourself or is there a repository with the updated version?

Did you ever get it to work as you expected?