1 // Copyright 2017 The PDFium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
6
7 #include "core/fpdfapi/page/cpdf_stitchfunc.h"
8
9 #include <utility>
10
11 #include "core/fpdfapi/parser/cpdf_array.h"
12 #include "core/fpdfapi/parser/cpdf_dictionary.h"
13 #include "core/fpdfapi/parser/fpdf_parser_utility.h"
14 #include "core/fxcrt/fx_safe_types.h"
15 #include "core/fxcrt/stl_util.h"
16
17 namespace {
18
19 constexpr uint32_t kRequiredNumInputs = 1;
20
21 } // namespace
22
CPDF_StitchFunc()23 CPDF_StitchFunc::CPDF_StitchFunc() : CPDF_Function(Type::kType3Stitching) {}
24
25 CPDF_StitchFunc::~CPDF_StitchFunc() = default;
26
v_Init(const CPDF_Object * pObj,VisitedSet * pVisited)27 bool CPDF_StitchFunc::v_Init(const CPDF_Object* pObj, VisitedSet* pVisited) {
28 if (m_nInputs != kRequiredNumInputs)
29 return false;
30
31 CHECK(pObj->IsDictionary() || pObj->IsStream());
32 RetainPtr<const CPDF_Dictionary> pDict = pObj->GetDict();
33 RetainPtr<const CPDF_Array> pFunctionsArray = pDict->GetArrayFor("Functions");
34 if (!pFunctionsArray)
35 return false;
36
37 RetainPtr<const CPDF_Array> pBoundsArray = pDict->GetArrayFor("Bounds");
38 if (!pBoundsArray)
39 return false;
40
41 RetainPtr<const CPDF_Array> pEncodeArray = pDict->GetArrayFor("Encode");
42 if (!pEncodeArray)
43 return false;
44
45 const uint32_t nSubs = fxcrt::CollectionSize<uint32_t>(*pFunctionsArray);
46 if (nSubs == 0)
47 return false;
48
49 // Check array sizes. The checks are slightly relaxed to allow the "Bounds"
50 // and "Encode" arrays to have more than the required number of elements.
51 {
52 if (pBoundsArray->size() < nSubs - 1)
53 return false;
54
55 FX_SAFE_UINT32 nExpectedEncodeSize = nSubs;
56 nExpectedEncodeSize *= 2;
57 if (!nExpectedEncodeSize.IsValid())
58 return false;
59
60 if (pEncodeArray->size() < nExpectedEncodeSize.ValueOrDie())
61 return false;
62 }
63
64 // Check sub-functions.
65 {
66 std::optional<uint32_t> nOutputs;
67 for (uint32_t i = 0; i < nSubs; ++i) {
68 RetainPtr<const CPDF_Object> pSub = pFunctionsArray->GetDirectObjectAt(i);
69 if (pSub == pObj)
70 return false;
71
72 std::unique_ptr<CPDF_Function> pFunc =
73 CPDF_Function::Load(std::move(pSub), pVisited);
74 if (!pFunc)
75 return false;
76
77 // Check that the input dimensionality is 1, and that all output
78 // dimensionalities are the same.
79 if (pFunc->InputCount() != kRequiredNumInputs) {
80 return false;
81 }
82
83 uint32_t nFuncOutputs = pFunc->OutputCount();
84 if (nFuncOutputs == 0)
85 return false;
86
87 if (nOutputs.has_value()) {
88 if (nOutputs != nFuncOutputs)
89 return false;
90 } else {
91 nOutputs = nFuncOutputs;
92 }
93 m_pSubFunctions.push_back(std::move(pFunc));
94 }
95 m_nOutputs = nOutputs.value();
96 }
97
98 m_bounds.reserve(nSubs + 1);
99 m_bounds.push_back(m_Domains[0]);
100 for (uint32_t i = 0; i < nSubs - 1; i++)
101 m_bounds.push_back(pBoundsArray->GetFloatAt(i));
102 m_bounds.push_back(m_Domains[1]);
103
104 m_encode = ReadArrayElementsToVector(pEncodeArray.Get(), nSubs * 2);
105 return true;
106 }
107
v_Call(pdfium::span<const float> inputs,pdfium::span<float> results) const108 bool CPDF_StitchFunc::v_Call(pdfium::span<const float> inputs,
109 pdfium::span<float> results) const {
110 float input = inputs[0];
111 size_t i;
112 for (i = 0; i + 1 < m_pSubFunctions.size(); i++) {
113 if (input < m_bounds[i + 1])
114 break;
115 }
116 input = Interpolate(input, m_bounds[i], m_bounds[i + 1], m_encode[i * 2],
117 m_encode[i * 2 + 1]);
118 return m_pSubFunctions[i]
119 ->Call(pdfium::span_from_ref(input), results)
120 .has_value();
121 }
122