wc3re/IffFile.cc

#include <cstring>

#include "IffFile.hh"
#include "util.hh"
#include "common.hh"

struct ChunkHeader {
  unsigned char typeID[4];
  uint32_t length;
};

IffFile::IffFile(Resource::Handle res)
  : res_(std::move(res)), footprint_(sizeof(IffFile))
{
  size_t pos = 0;
  while (pos < res_->size()) {
    roots_.push_back(parseObject(*this, res_->data()+pos, res_->size()-pos, footprint_));
    pos += roots_.back()->size() + 8;
  }
  footprint_ += sizeof(std::unique_ptr<Object>)*roots_.capacity();
}

IffFile::~IffFile()
{
}

static void _printStructure(IffFile::Object const& obj, unsigned level)
{
  for (unsigned i = 0;i < level;++i)
    putchar('\t');
  printf("%s Length %lu (0x%.lx)", obj.getType().c_str(), obj.size(), obj.size());
  
  if (obj.isForm()) {
    auto& form = dynamic_cast<IffFile::Form const&>(obj);
    printf(", Subtype %s\n", form.getSubtype().c_str());
    for(auto it = form.childrenBegin();it != form.childrenEnd();++it)
      _printStructure(*it, level+1);
  } else {
    try {
      printf(" = \"%s\"\n", static_cast<std::string>(obj).c_str());
    } catch(FormatException &ex) {
      printf("\n");
    }
  }
}

void IffFile::printStructure(unsigned level) const
{
  for (auto& root : *this)
    _printStructure(root, level);
}

std::unique_ptr<IffFile::Object>
IffFile::parseObject(IffFile& parent, uint8_t const* base, size_t length,
		     size_t& footprint)
{    
  if (length < 8)
    throw FormatException{"length < header size"};

  ChunkHeader header;
  memcpy(&header.typeID, base, 4);
  header.length = readU32BE(base+4);

  for (unsigned i = 0;i < 4;++i)
    if (!isprint(header.typeID[i]))
      throw FormatException{"Not an IFF chunk"};
  
  if (header.length > length-8)
    throw FormatException{"length < size in header"};
  
  if(memcmp(header.typeID, "FORM", 4) == 0)
    return std::unique_ptr<Object>(new Form(parent, "FORM", base+8,
					    static_cast<size_t>(header.length),
					    footprint));
  else
      return std::unique_ptr<Object>(new Object(parent, std::string(reinterpret_cast<char const*>(header.typeID), 4),
					      base+8, static_cast<size_t>(header.length),
					      footprint));
}

namespace {
  IffFile::Object& _getObject(std::string const& spec,
			      std::vector<std::unique_ptr<IffFile::Object> > const& container)
  {
    auto sepPos = spec.find(':');
    auto name = spec.substr(0, sepPos);
    unsigned matchCnt = 0;
    if (sepPos != std::string::npos)
      matchCnt = std::stoul(spec.substr(sepPos+1));
    
    for (auto& obj : container) {
      if (obj->isForm()) {
	auto form = dynamic_cast<IffFile::Form const*>(obj.get());
	if (form->getSubtype() == name) {
	  if (!matchCnt) {
	    return *obj;
	  } else {
	    --matchCnt;
	  }
	}
      } else if (obj->getType() == name) {
	if (!matchCnt) {
	  return *obj;
	} else {
	  --matchCnt;
	} 
      }
    }

    throw PathException{"Not found: " + spec};
  }
  
}

IffFile::Object& IffFile::getObject(std::string const& spec) const
{
  return _getObject(spec, roots_);
}

IffFile::Object& IffFile::Form::getObject(std::string const& spec) const
{
  return _getObject(spec, children_);
}

IffFile::Object::Object(IffFile& parent, std::string type, uint8_t const* base,
			size_t length, size_t& footprint)
  : parent_(parent), base_(base), length_(length), type_(std::move(type))
{
  footprint += sizeof(Object)+type_.capacity();
}

IffFile::Object::operator std::string() const
{
  // Check if BLOB is string
  enum class State { STARTASCII, NULLS, NOT_STRING };
  State state = State::STARTASCII;
  for (char const& c : *this) {
    switch(state) {
    case State::STARTASCII:
      if (isprint(static_cast<unsigned char>(c)))
	continue;
      if (c == '\0')
	state = State::NULLS;
      else
	state = State::NOT_STRING;
      break;
    case State::NULLS:
      if (c != '\0')
	state = State::NOT_STRING;
      break;
    case State::NOT_STRING:
      break;
    }

    if (state == State::NOT_STRING)
      break;
  }
    
  if (state == State::NULLS)
    return std::string(reinterpret_cast<char const*>(base_));
  else if (state == State::STARTASCII)
    return std::string(reinterpret_cast<char const*>(base_), length_);
  else
    throw FormatException{"BLOB not string"};
}

IffFile::Form::Form(IffFile& parent, std::string type, uint8_t const* base,
		    size_t length, size_t& footprint)
  : Object(parent, std::move(type), base, length, footprint)
{
  if (length < 4)
    throw FormatException{"length < subtype id length"};

  unsigned strLen = 4;
  for (unsigned i = 0;i < 4;++i) {
    if ((i > 0) && (base_[i] == '\0')) {
      strLen = i;
      break;
    }
    if (!isprint(base_[i]))
      throw FormatException{"Subtype not printable"};
  }
  subtype_ = std::string(reinterpret_cast<char const*>(base_), strLen);

  size_t pos = 4;
  while (pos+8 < length) {
    children_.push_back(parseObject(parent_, base_+pos, length-pos, footprint));
    pos += 8 + children_.back()->size();
    
    if (pos%2 != 0)
      ++pos;
  }

  footprint += sizeof(Form) + sizeof(std::unique_ptr<Object>)*children_.capacity() + subtype_.size() - sizeof(Object);
}