1 // Copyright 2014 PDFium Authors. All rights reserved.
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 // Original code is licensed as follows:
7 /*
8 * Copyright 2007 ZXing authors
9 *
10 * Licensed under the Apache License, Version 2.0 (the "License");
11 * you may not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
13 *
14 * http://www.apache.org/licenses/LICENSE-2.0
15 *
16 * Unless required by applicable law or agreed to in writing, software
17 * distributed under the License is distributed on an "AS IS" BASIS,
18 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 * See the License for the specific language governing permissions and
20 * limitations under the License.
21 */
22
23 #include "fxbarcode/common/reedsolomon/BC_ReedSolomon.h"
24
25 #include <memory>
26 #include <utility>
27
28 #include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256.h"
29 #include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256Poly.h"
30 #include "third_party/base/ptr_util.h"
31
CBC_ReedSolomonEncoder(CBC_ReedSolomonGF256 * field)32 CBC_ReedSolomonEncoder::CBC_ReedSolomonEncoder(CBC_ReedSolomonGF256* field)
33 : m_field(field) {}
34
~CBC_ReedSolomonEncoder()35 CBC_ReedSolomonEncoder::~CBC_ReedSolomonEncoder() {}
36
Init()37 void CBC_ReedSolomonEncoder::Init() {
38 m_cachedGenerators.push_back(
39 pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(m_field.Get(), 1));
40 }
41
BuildGenerator(size_t degree)42 CBC_ReedSolomonGF256Poly* CBC_ReedSolomonEncoder::BuildGenerator(
43 size_t degree) {
44 if (degree >= m_cachedGenerators.size()) {
45 CBC_ReedSolomonGF256Poly* lastGenerator = m_cachedGenerators.back().get();
46 for (size_t d = m_cachedGenerators.size(); d <= degree; ++d) {
47 std::vector<int32_t> temp = {1, m_field->Exp(d - 1)};
48 CBC_ReedSolomonGF256Poly temp_poly;
49 if (!temp_poly.Init(m_field.Get(), &temp))
50 return nullptr;
51
52 auto nextGenerator = lastGenerator->Multiply(&temp_poly);
53 if (!nextGenerator)
54 return nullptr;
55
56 lastGenerator = nextGenerator.get();
57 m_cachedGenerators.push_back(std::move(nextGenerator));
58 }
59 }
60 return m_cachedGenerators[degree].get();
61 }
62
Encode(std::vector<int32_t> * toEncode,size_t ecBytes)63 bool CBC_ReedSolomonEncoder::Encode(std::vector<int32_t>* toEncode,
64 size_t ecBytes) {
65 if (ecBytes == 0)
66 return false;
67
68 if (toEncode->size() <= ecBytes)
69 return false;
70
71 CBC_ReedSolomonGF256Poly* generator = BuildGenerator(ecBytes);
72 if (!generator)
73 return false;
74
75 size_t dataBytes = toEncode->size() - ecBytes;
76 std::vector<int32_t> infoCoefficients(dataBytes);
77 for (size_t x = 0; x < dataBytes; x++)
78 infoCoefficients[x] = (*toEncode)[x];
79
80 CBC_ReedSolomonGF256Poly info;
81 if (!info.Init(m_field.Get(), &infoCoefficients))
82 return false;
83
84 auto infoTemp = info.MultiplyByMonomial(ecBytes, 1);
85 if (!infoTemp)
86 return false;
87
88 auto remainder = infoTemp->Divide(generator);
89 if (!remainder)
90 return false;
91
92 const auto& coefficients = remainder->GetCoefficients();
93 size_t numZeroCoefficients =
94 ecBytes > coefficients.size() ? ecBytes - coefficients.size() : 0;
95 for (size_t i = 0; i < numZeroCoefficients; i++)
96 (*toEncode)[dataBytes + i] = 0;
97 for (size_t y = 0; y < coefficients.size(); y++)
98 (*toEncode)[dataBytes + numZeroCoefficients + y] = coefficients[y];
99 return true;
100 }
101