Reading strings from WDB cache files.

[Nesox]

Hi, I've been working some on a WDB reader lately I can't seem to figure how they compute the length, sometimes it's the first byte before the string but often it's packed in some weird way.
I remember pre mop they were just stored as normal null terminated strings, anyone who has done this before that could shed some light on this?

It's used like this in DbQuestCache_Unpack and many other places.

  LOWORD(a2a) = 0x800;
  v6 = CDataStore::GetStrLen((CDataStore *)&v9, (int)store);
  v7 = v6;
  *(_DWORD *)(this + 0x14) = v6;
  result = CDataStore::GetCString_2(v3, (void *)(this + 0x14), v6);

  thisa = v3;
  LOWORD(v14) = 0x800;
  v10 = 2 * CDataStore::GetStrLen((CDataStore *)&thisa, a3);
  *(_DWORD *)(v4 + 96) = v10 | CDataStore_sub_65BD22((CDataStore *)&thisa);// Set length for Name
  LOBYTE(a3) = 0;
  *(_DWORD *)(v4 + 608) = sub_67B804((CDataStore *)&thisa, a3);// Set length for ObjectiveText
  LOBYTE(a3) = 0;
  *(_DWORD *)(v4 + 3608) = sub_67B804((CDataStore *)&thisa, a3);// Set length for Description
  LOBYTE(a3) = 0;
  v11 = 2 * CDataStore::GetStrLen((CDataStore *)&thisa, a3);
  *(_DWORD *)(v4 + 6608) = v11 | CDataStore_sub_65BD22((CDataStore *)&thisa);// Set length for EndText
  LOBYTE(a3) = 0;
  *(_DWORD *)(v4 + 7148) = sub_6816AA((CDataStore *)&thisa, a3);// Set length for PortraitGiverText
  LOBYTE(a3) = 0;
  *(_DWORD *)(v4 + 8172) = CDataStore::GetStrLen((CDataStore *)&thisa, a3);// Set length for PortraitGiverName
  LOBYTE(a3) = 0;
  *(_DWORD *)(v4 + 8428) = sub_6816AA((CDataStore *)&thisa, a3);// Set length for PortraitTurnInDescription
  LOBYTE(a3) = 0;
  *(_DWORD *)(v4 + 9452) = CDataStore::GetStrLen((CDataStore *)&thisa, a3);// Set length for PortraitTurnInName
  LOBYTE(a3) = 0;
  *(_DWORD *)(v4 + 9708) = sub_661CEC((CDataStore *)&thisa, a3);// Set length for CompletionText 

All related subs

unsigned int __thiscall sub_67B804(CDataStore *this, int _18)
{
  int v2; // ebx@1
  unsigned int v3; // eax@1
  int a2; // [sp+Ch] [bp-4h]@0

  LOBYTE(a2) = 0;
  v2 = (int)this;
  v3 = CDataStore::GetStrLen(this, a2);
  LOBYTE(a2) = 0;
  return 16 * v3 | CDataStore::GetLoByte(v2, a2);
}

int __thiscall sub_661CEC(CDataStore *this, int _18)
{
  unsigned int v2; // eax@1
  int a2; // [sp+Ch] [bp-4h]@0

  LOBYTE(a2) = 0;
  v2 = CDataStore::GetStrLen(this, a2);
  LOBYTE(a2) = 0;
  return 8 * v2 | sub_65BB09(a2);
}

unsigned int __thiscall CDataStore::GetStrLen(CDataStore *this, int a2)
{
  char v3; // cl@1
  unsigned int result; // eax@2
  unsigned int v5; // esi@3
  unsigned __int8 v6; // [sp+7h] [bp-1h]@1

  v3 = BYTE1(this->m_data);
  v6 = 0;
  if ( v3 == 8 )
  {
    CDataStore::GetInt8((CDataStore *)&v6);
    result = v6;
  }
  else
  {
    v5 = (unsigned int)LOBYTE(this->m_data) >> v3;
    CDataStore::GetInt8((CDataStore *)&v6);
    result = (v5 << BYTE1(this->m_data)) | ((unsigned int)v6 >> (8 - BYTE1(this->m_data)));
    LOBYTE(this->m_data) = v6 << BYTE1(this->m_data);
  }
  return result;
}

unsigned int __thiscall CDataStore::GetLoByte(CDataStore *this, int a2)
{
  CDataStore *v2; // esi@1
  unsigned __int8 v3; // cl@1
  unsigned __int8 v4; // dl@2
  unsigned int result; // eax@2
  unsigned int v6; // edi@5
  unsigned __int8 v7; // bl@5
  char v8; // dl@5
  unsigned int v9; // eax@5
  char v10; // cl@5
  unsigned __int8 v11; // [sp+7h] [bp-1h]@3

  v2 = this;
  v3 = BYTE1(this->m_data);
  if ( v3 > 4u )
  {
    v11 = 0;
    if ( v3 == 8 )
    {
      CDataStore::GetInt8((CDataStore *)&v11);
      result = (unsigned int)v11 >> 4;
      LOBYTE(v2->m_data) = 16 * v11;
      BYTE1(v2->m_data) = 4;
    }
    else
    {
      v6 = (unsigned int)LOBYTE(v2->m_data) >> v3;
      CDataStore::GetInt8((CDataStore *)&v11);
      v7 = v11;
      v8 = BYTE1(v2->m_data) - 4;
      v9 = (unsigned int)v11 >> (8 - v8);
      v10 = BYTE1(v2->m_data) - 4;
      BYTE1(v2->m_data) = v8;
      result = (v6 << v10) | v9;
      LOBYTE(v2->m_data) = v7 << v10;
    }
  }
  else
  {
    v4 = LOBYTE(v2->m_data);
    result = (unsigned int)v4 >> 4;
    LOBYTE(v2->m_data) = 16 * v4;
    BYTE1(v2->m_data) = v3 + 4;
  }
  return result;
}

unsigned int __thiscall CDataStore_sub_65BD22(CDataStore *this)
{
  CDataStore *v1; // esi@1
  unsigned __int8 v2; // cl@3
  unsigned int result; // eax@3
  char v4; // [sp+7h] [bp-1h]@2

  v1 = this;
  if ( BYTE1(this->m_data) == 8 )
  {
    v4 = 0;
    CDataStore::GetInt8((CDataStore *)&v4);
    LOBYTE(v1->m_data) = v4;
    BYTE1(v1->m_data) = 0;
  }
  v2 = LOBYTE(v1->m_data);
  result = (unsigned int)v2 >> 7;
  ++BYTE1(v1->m_data);
  LOBYTE(v1->m_data) = 2 * v2;
  return result;
}

unsigned int __thiscall CDataStore_sub_65BB09(CDataStore *this, int a2)
{
  CDataStore *v2; // esi@1
  unsigned __int8 v3; // cl@1
  unsigned __int8 v4; // dl@2
  unsigned int result; // eax@2
  unsigned int v6; // edi@5
  unsigned __int8 v7; // bl@5
  char v8; // dl@5
  unsigned int v9; // eax@5
  char v10; // cl@5
  unsigned __int8 v11; // [sp+7h] [bp-1h]@3

  v2 = this;
  v3 = BYTE1(this->m_data);
  if ( v3 > 5u )
  {
    v11 = 0;
    if ( v3 == 8 )
    {
      CDataStore::GetInt8((CDataStore *)&v11);
      result = (unsigned int)v11 >> 5;
      LOBYTE(v2->m_data) = 8 * v11;
      BYTE1(v2->m_data) = 3;
    }
    else
    {
      v6 = (unsigned int)LOBYTE(v2->m_data) >> v3;
      CDataStore::GetInt8((CDataStore *)&v11);
      v7 = v11;
      v8 = BYTE1(v2->m_data) - 5;
      v9 = (unsigned int)v11 >> (8 - v8);
      v10 = BYTE1(v2->m_data) - 5;
      BYTE1(v2->m_data) = v8;
      result = (v6 << v10) | v9;
      LOBYTE(v2->m_data) = v7 << v10;
    }
  }
  else
  {
    v4 = LOBYTE(v2->m_data);
    result = (unsigned int)v4 >> 5;
    LOBYTE(v2->m_data) = 8 * v4;
    BYTE1(v2->m_data) = v3 + 3;
  }
  return result;
} 

[doityourself]

These things are just for reading the packet which is sent by the server. not reading the .wdb file.
reading wdb files is still the same thing...

[Nesox]

These things are just for reading the packet which is sent by the server. not reading the .wdb file.
reading wdb files is still the same thing...

Lol, they use the cdatastore functions for reading the bytes from the cache file when wow loads them from disk at startup -_-

[doityourself]

and the namelength is read/written with the bitstream shit.

Your CDataStore::GetStrLen = BitUnpack::GetBitCT8
0x67B804 = BitUnpack::GetBitCT12
0x661CEC = BitUnpack::GetBitCT11
0x65BD22 = BitUnpack::GetBit
Your CDataStore::GetLoByte = BitUnpack::GetBitCT4
0x65BB09 = BitUnpack::GetBitCT3
0x6816AA = BitUnpack::GetBitCT10

[Nesox]

and the namelength is read/written with the bitstream shit.

Your CDataStore::GetStrLen = BitUnpack::GetBitCT8
0x67B804 = BitUnpack::GetBitCT12
0x661CEC = BitUnpack::GetBitCT11
0x65BD22 = BitUnpack::GetBit
Your CDataStore::GetLoByte = BitUnpack::GetBitCT4
0x65BB09 = BitUnpack::GetBitCT3
0x6816AA = BitUnpack::GetBitCT10

Ok, thanks.