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179971c, posted Thu Feb 09, 2023 3:08 am (75369)

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Need help to convert this function (DecryptMemory) to C# code, any code simplify or improve readability are also welcome.

Code:

System_Byte_array *__stdcall ResourceManager__DecryptMemory(ResourceManager_o *this, System_String_o *strPath, System_Byte_array *enryptedMemory, const MethodInfo *method)
{
  System_Byte_array *v4; // rbp
  System_String_o *v5; // r14
  __int64 v6; // r13
  int v7; // ebx
  __int64 v8; // r8
  __int64 v9; // r9
  __int64 v10; // rsi
  int v11; // edi
  __int64 v12; // r8
  __int64 v13; // r9
  __int64 v14; // r8
  __int64 v15; // r9
  System_Array_o *v16; // rax
  int v17; // ebx
  int v18; // er15
  int32_t v19; // er14
  int v20; // edx
  uint64_t v21; // r12
  int v22; // edi
  int v23; // eax
  __int64 v24; // rcx
  __int64 v25; // rdx
  System_String_o *v26; // rdi
  System_String_o *v27; // rdi
  System_Text_Encoding_o *v28; // rax
  __int64 v30; // rax
  __int64 v31; // rax
  __int64 v32; // rax
  __int64 v33; // rax
  __int64 v34; // rax
  System_Byte_array *dst; // [rsp 30h] [rbp-48h]
  System_String_o *v36; // [rsp 88h] [rbp 10h]
  System_Byte_array *src; // [rsp 90h] [rbp 18h]

  v36 = strPath;
  v4 = enryptedMemory;
  v5 = strPath;
  if ( !byte_18383084A )
  {
    sub_1802908E0(58372i64, strPath, enryptedMemory, method);
    byte_18383084A = 1;
  }
  if ( !v4 )
    goto LABEL_34;
  if ( SLODWORD(v4->max_length) < 8 )
    return 0i64;
  v6 = sub_1802906B0(ulong___TypeInfo, 4i64, enryptedMemory, method);
  System_Runtime_CompilerServices_RuntimeHelpers__InitializeArray_6459807856(
    (System_Array_o *)v6,
    Field__PrivateImplementationDetails__BF43CDF8D96CA09E1591D08469EDFB9E391A8259,
    0i64);
  v7 = v4->max_length;
  v10 = sub_1802906B0(byte___TypeInfo, (unsigned int)(v7 - 8), v8, v9);
  v11 = (v7 - 8) / 16;
  dst = (System_Byte_array *)sub_1802906B0(byte___TypeInfo, 16i64, v12, v13);
  v16 = (System_Array_o *)sub_1802906B0(byte___TypeInfo, 16i64, v14, v15);
  v17 = 0;
  src = (System_Byte_array *)v16;
  v18 = 0;
  if ( v11 > 0 )
  {
    v19 = 0;
    do
    {
      System_Array__Copy_6457446880((System_Array_o *)v4, v19   8, v16, 0, 16, 0i64);
      if ( !v6 )
        goto LABEL_34;
      v20 = v18 % *(_DWORD *)(v6   24);
      if ( (unsigned int)v20 >= *(_DWORD *)(v6   24) )
      {
        v30 = ((__int64 (*)(void))sub_180290860)();
        sub_180290A30(v30, 0i64);
      }
      v21 = *(_QWORD *)(v6   8i64 * v20   32);
      if ( (Utility_TypeInfo->_2.bitflags2 & 2) != 0 && !Utility_TypeInfo->_2.cctor_finished )
        il2cpp_runtime_class_init();
      Utility__shuffle16(dst, src, v21, 0i64);
      System_Array__Copy_6457446880((System_Array_o *)dst, 0, (System_Array_o *)v10, v19, 16, 0i64);
      v16 = (System_Array_o *)src;
        v18;
      v19  = 16;
    }
    while ( v18 < v11 );
    v5 = v36;
  }
  v22 = 16 * v11;
  if ( !v10 )
    goto LABEL_34;
  while ( 1 )
  {
    v23 = *(_DWORD *)(v10   24);
    if ( v22 >= v23 )
      break;
    v24 = v22;
    v25 = v22   8i64;
    if ( (unsigned int)v25 >= LODWORD(v4->max_length) )
    {
      v32 = sub_180290860(v22, v25, enryptedMemory, method);
      sub_180290A30(v32, 0i64);
    }
    if ( v22 >= (unsigned int)v23 )
    {
      v31 = sub_180290860(v22, v25, enryptedMemory, method);
      sub_180290A30(v31, 0i64);
    }
      v22;
    *(_BYTE *)(v24   v10   32) = v4->m_Items[v25];
  }
  if ( (System_IO_Path_TypeInfo->_2.bitflags2 & 2) != 0 && !System_IO_Path_TypeInfo->_2.cctor_finished )
    il2cpp_runtime_class_init();
  v26 = System_IO_Path__GetFileNameWithoutExtension(v5, 0i64);
  if ( (Utility_TypeInfo->_2.bitflags2 & 2) != 0 && !Utility_TypeInfo->_2.cctor_finished )
    il2cpp_runtime_class_init();
  v27 = Utility__sha1Hashed(v26, 0i64);
  v28 = System_Text_Encoding__get_ASCII(0i64);
  if ( !v28 )
LABEL_34:
    sub_180290A60(this, strPath, enryptedMemory, method);
  for ( enryptedMemory = (System_Byte_array *)((__int64 (__fastcall *)(System_Text_Encoding_o *, System_String_o *, const MethodInfo *))v28->klass->vtable._18_GetBytes.methodPtr)(
                                                v28,
                                                v27,
                                                v28->klass->vtable._18_GetBytes.method);
        ;
        *(_BYTE *)(v17     v10   32) ^= enryptedMemory->m_Items[(int)strPath] )
  {
    this = (ResourceManager_o *)*(unsigned int *)(v10   24);
    if ( v17 >= (int)this )
      break;
    method = (const MethodInfo *)v17;
    if ( v17 >= (unsigned int)this )
    {
      v34 = sub_180290860(this, strPath, enryptedMemory, v17);
      sub_180290A30(v34, 0i64);
    }
    if ( !enryptedMemory )
      goto LABEL_34;
    strPath = (System_String_o *)(unsigned int)(v17 >> 31);
    LODWORD(strPath) = v17 % SLODWORD(enryptedMemory->max_length);
    if ( (unsigned int)strPath >= LODWORD(enryptedMemory->max_length) )
    {
      v33 = sub_180290860(this, strPath, enryptedMemory, v17);
      sub_180290A30(v33, 0i64);
    }
  }
  return (System_Byte_array *)v10;
}

Code:

internal static readonly .__StaticArrayInitTypeSize=32 BF43CDF8D96CA09E1591D08469EDFB9E391A8259 /*Metadata offset 0x5752D2*/;
3D 06 F4 2B C5 7A 9E 18 D1 64 F2 8B 05 EA 97 3C
C3 F7 D5 91 04 A2 6B E8 A4 2F 1E D0 73 8B 9C 56

Code:

__int64 __fastcall sub_1802906B0(__int64 a1, unsigned int a2)
{
  return il2cpp_array_new_specific_0(a1, a2);
}

179971c, posted Mon Feb 13, 2023 9:57 pm (75418)

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Since no one answered and I have solved it myself, this post is closed.