| // Copyright 2014 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 |
| // Original code is licensed as follows: |
| /* |
| * Copyright 2007 ZXing authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256.h" |
| |
| #include <vector> |
| |
| #include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256Poly.h" |
| |
| CBC_ReedSolomonGF256::CBC_ReedSolomonGF256(int32_t primitive) { |
| int32_t x = 1; |
| for (int32_t j = 0; j < 256; j++) { |
| m_expTable[j] = x; |
| x <<= 1; |
| if (x >= 0x100) { |
| x ^= primitive; |
| } |
| } |
| for (int32_t i = 0; i < 255; i++) { |
| m_logTable[m_expTable[i]] = i; |
| } |
| m_logTable[0] = 0; |
| } |
| |
| void CBC_ReedSolomonGF256::Init() { |
| m_zero = |
| std::make_unique<CBC_ReedSolomonGF256Poly>(this, std::vector<int32_t>{0}); |
| m_one = |
| std::make_unique<CBC_ReedSolomonGF256Poly>(this, std::vector<int32_t>{1}); |
| } |
| |
| CBC_ReedSolomonGF256::~CBC_ReedSolomonGF256() = default; |
| |
| std::unique_ptr<CBC_ReedSolomonGF256Poly> CBC_ReedSolomonGF256::BuildMonomial( |
| int32_t degree, |
| int32_t coefficient) { |
| if (degree < 0) |
| return nullptr; |
| |
| if (coefficient == 0) |
| return m_zero->Clone(); |
| |
| std::vector<int32_t> coefficients(degree + 1); |
| coefficients[0] = coefficient; |
| return std::make_unique<CBC_ReedSolomonGF256Poly>(this, coefficients); |
| } |
| |
| // static |
| int32_t CBC_ReedSolomonGF256::AddOrSubtract(int32_t a, int32_t b) { |
| return a ^ b; |
| } |
| |
| int32_t CBC_ReedSolomonGF256::Exp(int32_t a) { |
| return m_expTable[a]; |
| } |
| |
| Optional<int32_t> CBC_ReedSolomonGF256::Inverse(int32_t a) { |
| if (a == 0) |
| return pdfium::nullopt; |
| return m_expTable[255 - m_logTable[a]]; |
| } |
| |
| int32_t CBC_ReedSolomonGF256::Multiply(int32_t a, int32_t b) { |
| if (a == 0 || b == 0) { |
| return 0; |
| } |
| if (a == 1) { |
| return b; |
| } |
| if (b == 1) { |
| return a; |
| } |
| return m_expTable[(m_logTable[a] + m_logTable[b]) % 255]; |
| } |