// Copyright 2026 Google LLC

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//      http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

//

///////////////////////////////////////////////////////////////////////////

#include <cstdint>

#include <cstddef>

#include <cstdlib>

#include <new>

#include <string>

#include "dcmtk/dcmdata/dctk.h"

#include "dcmtk/dcmdata/dcistrmb.h"

#include "dcmtk/dcmdata/dcdeftag.h"

#include "dcmtk/dcmdata/dcxfer.h"

static constexpr std::size_t kNewNothrowCap = 8 * 1024 * 1024;

void* operator new(std::size_t n, const std::nothrow_t&) noexcept {

  if (n > kNewNothrowCap) return nullptr;

  try { return ::operator new(n); } catch (...) { return nullptr; }

}

void* operator new[](std::size_t n, const std::nothrow_t&) noexcept {

  if (n > kNewNothrowCap) return nullptr;

  try { return ::operator new[](n); } catch (...) { return nullptr; }

}

static void walkDataset(DcmItem* item) {

  if (!item) return;

  DcmStack stack;

  if (item->nextObject(stack, OFTrue).good()) {

    do {

      DcmObject* obj = stack.top();

      if (!obj) break;

      (void)obj->ident();

      (void)obj->getTag();

    } while (item->nextObject(stack, OFFalse).good());

  }

}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {

  static bool dict_set = (setenv("DCMDICTPATH", "/out/dicom.dic", 0), true);

  (void)dict_set;

  DcmInputBufferStream in;

  in.setBuffer((void*)data, size);

  in.setEos();

  DcmFileFormat file;

  const Uint32 kMaxReadLen = 256 * 1024;

  if (file.read(in, EXS_Unknown, EGL_noChange, kMaxReadLen).good()) {

    if (auto* ds = file.getDataset()) {

      (void)ds->chooseRepresentation(EXS_LittleEndianExplicit, nullptr);

      (void)ds->calcElementLength(EXS_LittleEndianExplicit, EET_ExplicitLength);

      OFString s;

      (void)ds->findAndGetOFString(DCM_PatientName, s);

      (void)ds->findAndGetOFString(DCM_StudyInstanceUID, s);

      (void)ds->findAndGetOFString(DCM_SOPClassUID, s);

      walkDataset(ds);

    }

  }

  return 0;

}