CUtlString::operator+=

/* CUtlString::TEMPNAMEPLACEHOLDERVALUE(CUtlString const&) */

CUtlString * __thiscall CUtlString::operator+=(CUtlString *this,CUtlString *param_1)

{
  int iVar1;
  size_t __n;
  size_t sVar2;
  undefined1 *__src;
  int iVar3;
  int local_20;
  
  if (*(int *)(this + 0xc) == 0) {
    local_20 = 0;
  }
  else {
    local_20 = *(int *)(this + 0xc) + -1;
  }
  sVar2 = *(int *)(param_1 + 0xc) - 1;
  if (*(int *)(param_1 + 0xc) == 0) {
    sVar2 = 0;
  }
  iVar1 = 0;
  if (0 < (int)(local_20 + sVar2)) {
    iVar1 = local_20 + sVar2 + 1;
  }
  CUtlBinaryBlock::SetLength((CUtlBinaryBlock *)this,iVar1);
  iVar1 = *(int *)(this + 0xc);
  if (iVar1 == 0) {
    iVar3 = 0;
  }
  else {
    iVar3 = iVar1 + -1;
  }
  __n = iVar3 - local_20;
  if ((int)sVar2 < iVar3 - local_20) {
    __n = sVar2;
  }
  __src = &DAT_00d539c2;
  if (*(int *)(param_1 + 0xc) != 0) {
    __src = *(undefined1 **)param_1;
  }
  if (iVar1 == 0) {
    CUtlBinaryBlock::SetLength((CUtlBinaryBlock *)this,1);
    **(undefined1 **)this = 0;
  }
  memcpy((void *)(local_20 + *(int *)this),__src,__n);
  *(undefined1 *)(*(int *)this + iVar3) = 0;
  return this;
}