C++ Branch::Render方法代码示例

void Block::Render(bool InLoop) {
  if (IsCheckedMultipleEntry && InLoop) {
    PrintIndented("label = 0;\n");
  }

  if (Code) {
    // Print code in an indented manner, even over multiple lines
    char *Start = const_cast<char*>(Code);
    while (*Start) {
      char *End = strchr(Start, '\n');
      if (End) *End = 0;
      PutIndented(Start);
      if (End) *End = '\n'; else break;
      Start = End+1;
    }
  }

  if (!ProcessedBranchesOut.size()) return;

  bool SetLabel = true; // in some cases it is clear we can avoid setting label, see later

  if (ProcessedBranchesOut.size() == 1 && ProcessedBranchesOut.begin()->second->Type == Branch::Direct) {
    SetLabel = false;
  }

  // A setting of the label variable (label = x) is necessary if it can
  // cause an impact. The main case is where we set label to x, then elsewhere
  // we check if label is equal to that value, i.e., that label is an entry
  // in a multiple block. We also need to reset the label when we enter
  // that block, so that each setting is a one-time action: consider
  //
  //    while (1) {
  //      if (check) label = 1;
  //      if (label == 1) { label = 0 }
  //    }
  //
  // (Note that this case is impossible due to fusing, but that is not
  // material here.) So setting to 0 is important just to clear the 1 for
  // future iterations.
  // TODO: When inside a loop, if necessary clear the label variable
  //       once on the top, and never do settings that are in effect clears

  // Fusing: If the next is a Multiple, we can fuse it with this block. Note
  // that we must be the Inner of a Simple, so fusing means joining a Simple
  // to a Multiple. What happens there is that all options in the Multiple
  // *must* appear in the Simple (the Simple is the only one reaching the
  // Multiple), so we can remove the Multiple and add its independent groups
  // into the Simple's branches.
  MultipleShape *Fused = Shape::IsMultiple(Parent->Next);
  if (Fused) {
    PrintDebug("Fusing Multiple to Simple\n");
    Parent->Next = Parent->Next->Next;
    Fused->RenderLoopPrefix();

    // When the Multiple has the same number of groups as we have branches,
    // they will all be fused, so it is safe to not set the label at all
    if (SetLabel && Fused->InnerMap.size() == ProcessedBranchesOut.size()) {
      SetLabel = false;
    }
  }

  // We must do this here, because blocks can be split and even comparing their Ids is not enough. We must check the conditions.
  for (BlockBranchMap::iterator iter = ProcessedBranchesOut.begin(); iter != ProcessedBranchesOut.end(); iter++) {
    if (!iter->second->Condition) {
      assert(!DefaultTarget); // Must be exactly one default
      DefaultTarget = iter->first;
    }
  }
  assert(DefaultTarget); // Must be a default

  ministring RemainingConditions;
  bool First = true;
  for (BlockBranchMap::iterator iter = ProcessedBranchesOut.begin();; iter++) {
    Block *Target;
    Branch *Details;
    if (iter != ProcessedBranchesOut.end()) {
      Target = iter->first;
      if (Target == DefaultTarget) continue; // done at the end
      Details = iter->second;
      assert(Details->Condition); // must have a condition if this is not the default target
    } else {
      Target = DefaultTarget;
      Details = ProcessedBranchesOut[DefaultTarget];
    }
    bool SetCurrLabel = SetLabel && Target->IsCheckedMultipleEntry;
    bool HasFusedContent = Fused && Fused->InnerMap.find(Target) != Fused->InnerMap.end();
    bool HasContent = SetCurrLabel || Details->Type != Branch::Direct || HasFusedContent || Details->Code;
    if (iter != ProcessedBranchesOut.end()) {
      // If there is nothing to show in this branch, omit the condition
      if (HasContent) {
        PrintIndented("%sif (%s) {\n", First ? "" : "} else ", Details->Condition);
        First = false;
      } else {
        if (RemainingConditions.size() > 0) RemainingConditions += " && ";
        RemainingConditions += "!(";
        RemainingConditions += Details->Condition;
        RemainingConditions += ")";
      }
    } else {
      if (HasContent) {
//.........这里部分代码省略.........