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 RetainPtr<const CPDF_Dictionary> pDict = pObj->GetDict();
32 if (!pDict)
33 return false;
34
35 RetainPtr<const CPDF_Array> pFunctionsArray = pDict->GetArrayFor("Functions");
36 if (!pFunctionsArray)
37 return false;
38
39 RetainPtr<const CPDF_Array> pBoundsArray = pDict->GetArrayFor("Bounds");
40 if (!pBoundsArray)
41 return false;
42
43 RetainPtr<const CPDF_Array> pEncodeArray = pDict->GetArrayFor("Encode");
44 if (!pEncodeArray)
45 return false;
46
47 const uint32_t nSubs = fxcrt::CollectionSize<uint32_t>(*pFunctionsArray);
48 if (nSubs == 0)
49 return false;
50
51 // Check array sizes. The checks are slightly relaxed to allow the "Bounds"
52 // and "Encode" arrays to have more than the required number of elements.
53 {
54 if (pBoundsArray->size() < nSubs - 1)
55 return false;
56
57 FX_SAFE_UINT32 nExpectedEncodeSize = nSubs;
58 nExpectedEncodeSize *= 2;
59 if (!nExpectedEncodeSize.IsValid())
60 return false;
61
62 if (pEncodeArray->size() < nExpectedEncodeSize.ValueOrDie())
63 return false;
64 }
65
66 // Check sub-functions.
67 {
68 absl::optional<uint32_t> nOutputs;
69 for (uint32_t i = 0; i < nSubs; ++i) {
70 RetainPtr<const CPDF_Object> pSub = pFunctionsArray->GetDirectObjectAt(i);
71 if (pSub == pObj)
72 return false;
73
74 std::unique_ptr<CPDF_Function> pFunc =
75 CPDF_Function::Load(std::move(pSub), pVisited);
76 if (!pFunc)
77 return false;
78
79 // Check that the input dimensionality is 1, and that all output
80 // dimensionalities are the same.
81 if (pFunc->CountInputs() != kRequiredNumInputs)
82 return false;
83
84 uint32_t nFuncOutputs = pFunc->CountOutputs();
85 if (nFuncOutputs == 0)
86 return false;
87
88 if (nOutputs.has_value()) {
89 if (nOutputs != nFuncOutputs)
90 return false;
91 } else {
92 nOutputs = nFuncOutputs;
93 }
94 m_pSubFunctions.push_back(std::move(pFunc));
95 }
96 m_nOutputs = nOutputs.value();
97 }
98
99 m_bounds.reserve(nSubs + 1);
100 m_bounds.push_back(m_Domains[0]);
101 for (uint32_t i = 0; i < nSubs - 1; i++)
102 m_bounds.push_back(pBoundsArray->GetFloatAt(i));
103 m_bounds.push_back(m_Domains[1]);
104
105 m_encode = ReadArrayElementsToVector(pEncodeArray.Get(), nSubs * 2);
106 return true;
107 }
108
v_Call(pdfium::span<const float> inputs,pdfium::span<float> results) const109 bool CPDF_StitchFunc::v_Call(pdfium::span<const float> inputs,
110 pdfium::span<float> results) const {
111 float input = inputs[0];
112 size_t i;
113 for (i = 0; i < m_pSubFunctions.size() - 1; i++) {
114 if (input < m_bounds[i + 1])
115 break;
116 }
117 input = Interpolate(input, m_bounds[i], m_bounds[i + 1], m_encode[i * 2],
118 m_encode[i * 2 + 1]);
119 return m_pSubFunctions[i]
120 ->Call(pdfium::make_span(&input, 1), results)
121 .has_value();
122 }
123