Add FPDFDest_GetLocationInPage API

Add an API to get the value of the /XYZ destination parameter.

This CL was originally from https://codereview.chromium.org/1960193003/ by
halcanary@.

Review-Url: https://codereview.chromium.org/2481743004

3 files changed, 116 insertions, 0 deletions

diff --git a/core/fpdfdoc/cpdf_dest.cpp b/core/fpdfdoc/cpdf_dest.cpp
index 312ef87346..51e2d0b534 100644
--- a/core/fpdfdoc/cpdf_dest.cpp
+++ b/core/fpdfdoc/cpdf_dest.cpp
@@ -8,6 +8,8 @@
 
 #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"
 
 namespace {
 
@@ -64,6 +66,53 @@ int CPDF_Dest::GetZoomMode() {
   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;
+
+  CPDF_Array* pArray = ToArray(m_pObj);
+  if (!pArray)
+    return false;
+
+  if (pArray->GetCount() < 5)
+    return false;
+
+  const CPDF_Name* xyz = ToName(pArray->GetDirectObjectAt(1));
+  if (!xyz || xyz->GetString() != "XYZ")
+    return false;
+
+  const CPDF_Number* numX = ToNumber(pArray->GetDirectObjectAt(2));
+  const CPDF_Number* numY = ToNumber(pArray->GetDirectObjectAt(3));
+  const CPDF_Number* numZoom = ToNumber(pArray->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;
+}
+
 FX_FLOAT CPDF_Dest::GetParam(int index) {
   CPDF_Array* pArray = ToArray(m_pObj);
   return pArray ? pArray->GetNumberAt(2 + index) : 0;
diff --git a/core/fpdfdoc/cpdf_dest.h b/core/fpdfdoc/cpdf_dest.h
index 8f38192fd8..527d1dcf8b 100644
--- a/core/fpdfdoc/cpdf_dest.h
+++ b/core/fpdfdoc/cpdf_dest.h
@@ -25,6 +25,13 @@ class CPDF_Dest {
   int GetZoomMode();
   FX_FLOAT GetParam(int index);
 
+  bool GetXYZ(bool* pHasX,
+              bool* pHasY,
+              bool* pHasZoom,
+              float* pX,
+              float* pY,
+              float* pZoom) const;
+
  private:
   CPDF_Object* m_pObj;
 };
diff --git a/core/fpdfdoc/cpdf_dest_unittest.cpp b/core/fpdfdoc/cpdf_dest_unittest.cpp
new file mode 100644
index 0000000000..d427ab66a0
--- /dev/null
+++ b/core/fpdfdoc/cpdf_dest_unittest.cpp
@@ -0,0 +1,60 @@
+// Copyright 2016 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/fpdfapi/parser/cpdf_array.h"
+#include "core/fpdfapi/parser/cpdf_null.h"
+#include "core/fpdfapi/parser/cpdf_number.h"
+#include "core/fpdfdoc/cpdf_dest.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/test_support.h"
+#include "third_party/base/ptr_util.h"
+
+TEST(cpdf_dest, GetXYZ) {
+  bool hasX;
+  bool hasY;
+  bool hasZoom;
+  float x;
+  float y;
+  float zoom;
+
+  auto dest = pdfium::MakeUnique<CPDF_Dest>();
+  EXPECT_FALSE(dest->GetXYZ(&hasX, &hasY, &hasZoom, &x, &y, &zoom));
+
+  auto array = pdfium::MakeUnique<CPDF_Array>();
+  array->AddInteger(0);  // Page Index.
+  array->AddName("XYZ");
+  array->AddNumber(4);  // X
+
+  // Not enough entries.
+  dest = pdfium::MakeUnique<CPDF_Dest>(array.get());
+  EXPECT_FALSE(dest->GetXYZ(&hasX, &hasY, &hasZoom, &x, &y, &zoom));
+
+  array->AddNumber(5);  // Y
+  array->AddNumber(6);  // Zoom.
+
+  dest = pdfium::MakeUnique<CPDF_Dest>(array.get());
+  EXPECT_TRUE(dest->GetXYZ(&hasX, &hasY, &hasZoom, &x, &y, &zoom));
+  EXPECT_TRUE(hasX);
+  EXPECT_TRUE(hasY);
+  EXPECT_TRUE(hasZoom);
+  EXPECT_EQ(4, x);
+  EXPECT_EQ(5, y);
+  EXPECT_EQ(6, zoom);
+
+  // Set zoom to 0.
+  array->SetAt(4, new CPDF_Number(0));
+  dest = pdfium::MakeUnique<CPDF_Dest>(array.get());
+  EXPECT_TRUE(dest->GetXYZ(&hasX, &hasY, &hasZoom, &x, &y, &zoom));
+  EXPECT_FALSE(hasZoom);
+
+  // Set values to null.
+  array->SetAt(2, new CPDF_Null);
+  array->SetAt(3, new CPDF_Null);
+  array->SetAt(4, new CPDF_Null);
+  dest = pdfium::MakeUnique<CPDF_Dest>(array.get());
+  EXPECT_TRUE(dest->GetXYZ(&hasX, &hasY, &hasZoom, &x, &y, &zoom));
+  EXPECT_FALSE(hasX);
+  EXPECT_FALSE(hasY);
+  EXPECT_FALSE(hasZoom);
+}