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      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_ReedSolomonGF256.h"
     24 
     25 #include <vector>
     26 
     27 #include "fxbarcode/common/reedsolomon/BC_ReedSolomonGF256Poly.h"
     28 #include "third_party/base/ptr_util.h"
     29 
     30 CBC_ReedSolomonGF256* CBC_ReedSolomonGF256::QRCodeField = nullptr;
     31 CBC_ReedSolomonGF256* CBC_ReedSolomonGF256::DataMatrixField = nullptr;
     32 
     33 void CBC_ReedSolomonGF256::Initialize() {
     34   QRCodeField = new CBC_ReedSolomonGF256(0x011D);
     35   QRCodeField->Init();
     36   DataMatrixField = new CBC_ReedSolomonGF256(0x012D);
     37   DataMatrixField->Init();
     38 }
     39 
     40 void CBC_ReedSolomonGF256::Finalize() {
     41   delete QRCodeField;
     42   QRCodeField = nullptr;
     43   delete DataMatrixField;
     44   DataMatrixField = nullptr;
     45 }
     46 
     47 CBC_ReedSolomonGF256::CBC_ReedSolomonGF256(int32_t primitive) {
     48   int32_t x = 1;
     49   for (int32_t j = 0; j < 256; j++) {
     50     m_expTable[j] = x;
     51     x <<= 1;
     52     if (x >= 0x100) {
     53       x ^= primitive;
     54     }
     55   }
     56   for (int32_t i = 0; i < 255; i++) {
     57     m_logTable[m_expTable[i]] = i;
     58   }
     59   m_logTable[0] = 0;
     60 }
     61 
     62 void CBC_ReedSolomonGF256::Init() {
     63   m_zero = pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(this, 0);
     64   m_one = pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>(this, 1);
     65 }
     66 
     67 CBC_ReedSolomonGF256::~CBC_ReedSolomonGF256() {}
     68 
     69 CBC_ReedSolomonGF256Poly* CBC_ReedSolomonGF256::GetZero() const {
     70   return m_zero.get();
     71 }
     72 
     73 CBC_ReedSolomonGF256Poly* CBC_ReedSolomonGF256::GetOne() const {
     74   return m_one.get();
     75 }
     76 
     77 std::unique_ptr<CBC_ReedSolomonGF256Poly> CBC_ReedSolomonGF256::BuildMonomial(
     78     int32_t degree,
     79     int32_t coefficient,
     80     int32_t& e) {
     81   if (degree < 0) {
     82     e = BCExceptionDegreeIsNegative;
     83     return nullptr;
     84   }
     85   if (coefficient == 0) {
     86     auto temp = m_zero->Clone();
     87     if (!temp)
     88       e = BCExceptionGeneric;
     89     return temp;
     90   }
     91   std::vector<int32_t> coefficients(degree + 1);
     92   coefficients[0] = coefficient;
     93   auto temp = pdfium::MakeUnique<CBC_ReedSolomonGF256Poly>();
     94   if (!temp->Init(this, &coefficients)) {
     95     e = BCExceptionGeneric;
     96     return nullptr;
     97   }
     98   return temp;
     99 }
    100 
    101 int32_t CBC_ReedSolomonGF256::AddOrSubtract(int32_t a, int32_t b) {
    102   return a ^ b;
    103 }
    104 
    105 int32_t CBC_ReedSolomonGF256::Exp(int32_t a) {
    106   return m_expTable[a];
    107 }
    108 
    109 int32_t CBC_ReedSolomonGF256::Log(int32_t a, int32_t& e) {
    110   if (a == 0) {
    111     e = BCExceptionAIsZero;
    112     return 0;
    113   }
    114   return m_logTable[a];
    115 }
    116 
    117 int32_t CBC_ReedSolomonGF256::Inverse(int32_t a, int32_t& e) {
    118   if (a == 0) {
    119     e = BCExceptionAIsZero;
    120     return 0;
    121   }
    122   return m_expTable[255 - m_logTable[a]];
    123 }
    124 
    125 int32_t CBC_ReedSolomonGF256::Multiply(int32_t a, int32_t b) {
    126   if (a == 0 || b == 0) {
    127     return 0;
    128   }
    129   if (a == 1) {
    130     return b;
    131   }
    132   if (b == 1) {
    133     return a;
    134   }
    135   return m_expTable[(m_logTable[a] + m_logTable[b]) % 255];
    136 }
    137