1 files changed, 153 insertions, 0 deletions
diff --git a/core/fpdfapi/page/cpdf_function.cpp b/core/fpdfapi/page/cpdf_function.cpp
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index 0000000000..635c53a95f
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+++ b/core/fpdfapi/page/cpdf_function.cpp
@@ -0,0 +1,153 @@
+// Copyright 2017 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.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#include "core/fpdfapi/page/cpdf_function.h"
+
+#include "core/fpdfapi/page/cpdf_expintfunc.h"
+#include "core/fpdfapi/page/cpdf_psfunc.h"
+#include "core/fpdfapi/page/cpdf_sampledfunc.h"
+#include "core/fpdfapi/page/cpdf_stitchfunc.h"
+#include "core/fpdfapi/parser/cpdf_array.h"
+#include "core/fpdfapi/parser/cpdf_dictionary.h"
+#include "core/fpdfapi/parser/cpdf_stream.h"
+#include "third_party/base/ptr_util.h"
+
+// static
+std::unique_ptr<CPDF_Function> CPDF_Function::Load(CPDF_Object* pFuncObj) {
+  std::unique_ptr<CPDF_Function> pFunc;
+  if (!pFuncObj)
+    return pFunc;
+
+  int iType = -1;
+  if (CPDF_Stream* pStream = pFuncObj->AsStream())
+    iType = pStream->GetDict()->GetIntegerFor("FunctionType");
+  else if (CPDF_Dictionary* pDict = pFuncObj->AsDictionary())
+    iType = pDict->GetIntegerFor("FunctionType");
+
+  Type type = IntegerToFunctionType(iType);
+  if (type == Type::kType0Sampled)
+    pFunc = pdfium::MakeUnique<CPDF_SampledFunc>();
+  else if (type == Type::kType2ExpotentialInterpolation)
+    pFunc = pdfium::MakeUnique<CPDF_ExpIntFunc>();
+  else if (type == Type::kType3Stitching)
+    pFunc = pdfium::MakeUnique<CPDF_StitchFunc>();
+  else if (type == Type::kType4PostScript)
+    pFunc = pdfium::MakeUnique<CPDF_PSFunc>();
+
+  if (!pFunc || !pFunc->Init(pFuncObj))
+    return nullptr;
+
+  return pFunc;
+}
+
+// static
+CPDF_Function::Type CPDF_Function::IntegerToFunctionType(int iType) {
+  switch (iType) {
+    case 0:
+    case 2:
+    case 3:
+    case 4:
+      return static_cast<Type>(iType);
+    default:
+      return Type::kTypeInvalid;
+  }
+}
+
+CPDF_Function::CPDF_Function(Type type)
+    : m_pDomains(nullptr), m_pRanges(nullptr), m_Type(type) {}
+
+CPDF_Function::~CPDF_Function() {
+  FX_Free(m_pDomains);
+  FX_Free(m_pRanges);
+}
+
+bool CPDF_Function::Init(CPDF_Object* pObj) {
+  CPDF_Stream* pStream = pObj->AsStream();
+  CPDF_Dictionary* pDict = pStream ? pStream->GetDict() : pObj->AsDictionary();
+
+  CPDF_Array* pDomains = pDict->GetArrayFor("Domain");
+  if (!pDomains)
+    return false;
+
+  m_nInputs = pDomains->GetCount() / 2;
+  if (m_nInputs == 0)
+    return false;
+
+  m_pDomains = FX_Alloc2D(float, m_nInputs, 2);
+  for (uint32_t i = 0; i < m_nInputs * 2; i++) {
+    m_pDomains[i] = pDomains->GetFloatAt(i);
+  }
+  CPDF_Array* pRanges = pDict->GetArrayFor("Range");
+  m_nOutputs = 0;
+  if (pRanges) {
+    m_nOutputs = pRanges->GetCount() / 2;
+    m_pRanges = FX_Alloc2D(float, m_nOutputs, 2);
+    for (uint32_t i = 0; i < m_nOutputs * 2; i++)
+      m_pRanges[i] = pRanges->GetFloatAt(i);
+  }
+  uint32_t old_outputs = m_nOutputs;
+  if (!v_Init(pObj))
+    return false;
+  if (m_pRanges && m_nOutputs > old_outputs) {
+    m_pRanges = FX_Realloc(float, m_pRanges, m_nOutputs * 2);
+    if (m_pRanges) {
+      memset(m_pRanges + (old_outputs * 2), 0,
+             sizeof(float) * (m_nOutputs - old_outputs) * 2);
+    }
+  }
+  return true;
+}
+
+bool CPDF_Function::Call(float* inputs,
+                         uint32_t ninputs,
+                         float* results,
+                         int* nresults) const {
+  if (m_nInputs != ninputs)
+    return false;
+
+  *nresults = m_nOutputs;
+  for (uint32_t i = 0; i < m_nInputs; i++) {
+    inputs[i] =
+        pdfium::clamp(inputs[i], m_pDomains[i * 2], m_pDomains[i * 2 + 1]);
+  }
+  v_Call(inputs, results);
+  if (!m_pRanges)
+    return true;
+
+  for (uint32_t i = 0; i < m_nOutputs; i++) {
+    results[i] =
+        pdfium::clamp(results[i], m_pRanges[i * 2], m_pRanges[i * 2 + 1]);
+  }
+  return true;
+}
+
+// See PDF Reference 1.7, page 170.
+float CPDF_Function::Interpolate(float x,
+                                 float xmin,
+                                 float xmax,
+                                 float ymin,
+                                 float ymax) const {
+  float divisor = xmax - xmin;
+  return ymin + (divisor ? (x - xmin) * (ymax - ymin) / divisor : 0);
+}
+
+const CPDF_SampledFunc* CPDF_Function::ToSampledFunc() const {
+  return m_Type == Type::kType0Sampled
+             ? static_cast<const CPDF_SampledFunc*>(this)
+             : nullptr;
+}
+
+const CPDF_ExpIntFunc* CPDF_Function::ToExpIntFunc() const {
+  return m_Type == Type::kType2ExpotentialInterpolation
+             ? static_cast<const CPDF_ExpIntFunc*>(this)
+             : nullptr;
+}
+
+const CPDF_StitchFunc* CPDF_Function::ToStitchFunc() const {
+  return m_Type == Type::kType3Stitching
+             ? static_cast<const CPDF_StitchFunc*>(this)
+             : nullptr;
+}