core/fpdfdoc/cpdf_dest.cpp

// Copyright 2016 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#include "core/fpdfdoc/cpdf_dest.h"

#include <algorithm>
#include <array>
#include <iterator>
#include <utility>

#include "core/fpdfapi/parser/cpdf_array.h"
#include "core/fpdfapi/parser/cpdf_document.h"
#include "core/fpdfapi/parser/cpdf_name.h"
#include "core/fpdfapi/parser/cpdf_number.h"
#include "core/fpdfdoc/cpdf_nametree.h"

namespace {

// These arrays are indexed by the PDFDEST_VIEW_* constants.

constexpr auto kZoomModes =
    std::to_array<const char*>({"Unknown", "XYZ", "Fit", "FitH", "FitV", "FitR",
                                "FitB", "FitBH", "FitBV"});

constexpr auto kZoomModeMaxParamCount =
    std::to_array<const uint8_t>({0, 3, 0, 1, 1, 4, 0, 1, 1});

}  // namespace

CPDF_Dest::CPDF_Dest(RetainPtr<const CPDF_Array> pArray)
    : array_(std::move(pArray)) {}

CPDF_Dest::CPDF_Dest(const CPDF_Dest& that) = default;

CPDF_Dest::~CPDF_Dest() = default;

// static
CPDF_Dest CPDF_Dest::Create(CPDF_Document* doc,
                            RetainPtr<const CPDF_Object> pDest) {
  if (!pDest) {
    return CPDF_Dest(nullptr);
  }

  if (pDest->IsString() || pDest->IsName()) {
    return CPDF_Dest(CPDF_NameTree::LookupNamedDest(doc, pDest->GetString()));
  }

  return CPDF_Dest(ToArray(pDest));
}

int CPDF_Dest::GetDestPageIndex(CPDF_Document* doc) const {
  if (!array_) {
    return -1;
  }

  RetainPtr<const CPDF_Object> pPage = array_->GetDirectObjectAt(0);
  if (!pPage) {
    return -1;
  }

  if (pPage->IsNumber()) {
    return pPage->GetInteger();
  }

  if (!pPage->IsDictionary()) {
    return -1;
  }

  return doc->GetPageIndex(pPage->GetObjNum());
}

std::vector<float> CPDF_Dest::GetScrollPositionArray() const {
  std::vector<float> result;
  if (array_) {
    // Skip over index 0 which contains destination page details, and index 1
    // which contains a parameter that describes the rest of the array.
    for (size_t i = 2; i < array_->size(); i++) {
      result.push_back(array_->GetFloatAt(i));
    }
  }
  return result;
}

int CPDF_Dest::GetZoomMode() const {
  if (!array_) {
    return 0;
  }
  RetainPtr<const CPDF_Object> pArray = array_->GetDirectObjectAt(1);
  if (!pArray) {
    return 0;
  }
  ByteString mode = pArray->GetString();
  for (size_t i = 1; i < std::size(kZoomModes); ++i) {
    if (mode == kZoomModes[i]) {
      return static_cast<int>(i);
    }
  }
  return 0;
}

bool CPDF_Dest::GetXYZ(bool* pHasX,
                       bool* pHasY,
                       bool* pHasZoom,
                       float* pX,
                       float* pY,
                       float* pZoom) const {
  *pHasX = false;
  *pHasY = false;
  *pHasZoom = false;

  if (!array_) {
    return false;
  }

  if (array_->size() < 5) {
    return false;
  }

  RetainPtr<const CPDF_Name> xyz = ToName(array_->GetDirectObjectAt(1));
  if (!xyz || xyz->GetString() != "XYZ") {
    return false;
  }

  RetainPtr<const CPDF_Number> numX = ToNumber(array_->GetDirectObjectAt(2));
  RetainPtr<const CPDF_Number> numY = ToNumber(array_->GetDirectObjectAt(3));
  RetainPtr<const CPDF_Number> numZoom = ToNumber(array_->GetDirectObjectAt(4));

  // If the value is a CPDF_Null then ToNumber will return nullptr.
  *pHasX = !!numX;
  *pHasY = !!numY;
  *pHasZoom = !!numZoom;

  if (numX) {
    *pX = numX->GetNumber();
  }
  if (numY) {
    *pY = numY->GetNumber();
  }

  // A zoom value of 0 is equivalent to a null value, so treat it as a null.
  if (numZoom) {
    float num = numZoom->GetNumber();
    if (num == 0.0) {
      *pHasZoom = false;
    } else {
      *pZoom = num;
    }
  }

  return true;
}

size_t CPDF_Dest::GetNumParams() const {
  if (!array_ || array_->size() < 2) {
    return 0;
  }

  size_t maxParamsForFitType = kZoomModeMaxParamCount[GetZoomMode()];
  size_t numParamsInArray = array_->size() - 2;
  return std::min(maxParamsForFitType, numParamsInArray);
}

float CPDF_Dest::GetParam(size_t index) const {
  return array_ ? array_->GetFloatAt(2 + index) : 0;
}