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 m_cachedGenerators.push_back(pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(
35 m_field.Get(), std::vector<int32_t>{1}));
36 }
37
~CBC_ReedSolomonEncoder()38 CBC_ReedSolomonEncoder::~CBC_ReedSolomonEncoder() {}
39
BuildGenerator(size_t degree)40 CBC_ReedSolomonGF256Poly* CBC_ReedSolomonEncoder::BuildGenerator(
41 size_t degree) {
42 if (degree >= m_cachedGenerators.size()) {
43 CBC_ReedSolomonGF256Poly* lastGenerator = m_cachedGenerators.back().get();
44 for (size_t d = m_cachedGenerators.size(); d <= degree; ++d) {
45 CBC_ReedSolomonGF256Poly temp_poly(m_field.Get(),
46 {1, m_field->Exp(d - 1)});
47 auto nextGenerator = lastGenerator->Multiply(&temp_poly);
48 if (!nextGenerator)
49 return nullptr;
50
51 lastGenerator = nextGenerator.get();
52 m_cachedGenerators.push_back(std::move(nextGenerator));
53 }
54 }
55 return m_cachedGenerators[degree].get();
56 }
57
Encode(std::vector<int32_t> * toEncode,size_t ecBytes)58 bool CBC_ReedSolomonEncoder::Encode(std::vector<int32_t>* toEncode,
59 size_t ecBytes) {
60 if (ecBytes == 0)
61 return false;
62
63 if (toEncode->size() <= ecBytes)
64 return false;
65
66 CBC_ReedSolomonGF256Poly* generator = BuildGenerator(ecBytes);
67 if (!generator)
68 return false;
69
70 size_t dataBytes = toEncode->size() - ecBytes;
71 std::vector<int32_t> infoCoefficients(dataBytes);
72 for (size_t x = 0; x < dataBytes; x++)
73 infoCoefficients[x] = (*toEncode)[x];
74
75 CBC_ReedSolomonGF256Poly info(m_field.Get(), infoCoefficients);
76 auto infoTemp = info.MultiplyByMonomial(ecBytes, 1);
77 if (!infoTemp)
78 return false;
79
80 auto remainder = infoTemp->Divide(generator);
81 if (!remainder)
82 return false;
83
84 const auto& coefficients = remainder->GetCoefficients();
85 size_t numZeroCoefficients =
86 ecBytes > coefficients.size() ? ecBytes - coefficients.size() : 0;
87 for (size_t i = 0; i < numZeroCoefficients; i++)
88 (*toEncode)[dataBytes + i] = 0;
89 for (size_t y = 0; y < coefficients.size(); y++)
90 (*toEncode)[dataBytes + numZeroCoefficients + y] = coefficients[y];
91 return true;
92 }
93