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| 1 // Copyright 2014 PDFium Authors. All rights reserved. | 1 // Copyright 2014 PDFium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com | 5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com |
| 6 | 6 |
| 7 #ifndef _JBIG2_ARITHMETIC_DECODER_H_ | 7 #ifndef _JBIG2_ARITHMETIC_DECODER_H_ |
| 8 #define _JBIG2_ARITHMETIC_DECODER_H_ | 8 #define _JBIG2_ARITHMETIC_DECODER_H_ |
| 9 #include "JBig2_Define.h" | 9 #include "JBig2_Define.h" |
| 10 #include "JBig2_BitStream.h" | 10 #include "JBig2_BitStream.h" |
| 11 #include "JBig2_ArithQe.h" | 11 #include "JBig2_ArithQe.h" |
| 12 typedef struct { | 12 typedef struct { |
| 13 unsigned int MPS; | 13 unsigned int MPS; |
| 14 unsigned int I; | 14 unsigned int I; |
| 15 } JBig2ArithCtx; | 15 } JBig2ArithCtx; |
| 16 class CJBig2_ArithDecoder : public CJBig2_Object | 16 class CJBig2_ArithDecoder : public CJBig2_Object { |
| 17 { | 17 public: |
| 18 public: | 18 CJBig2_ArithDecoder(CJBig2_BitStream* pStream); |
| 19 | 19 |
| 20 CJBig2_ArithDecoder(CJBig2_BitStream *pStream); | 20 ~CJBig2_ArithDecoder(); |
| 21 | 21 |
| 22 ~CJBig2_ArithDecoder(); | 22 int DECODE(JBig2ArithCtx* pCX); |
| 23 | 23 |
| 24 int DECODE(JBig2ArithCtx *pCX); | 24 private: |
| 25 private: | 25 void INITDEC(); |
| 26 | 26 |
| 27 void INITDEC(); | 27 void BYTEIN(); |
| 28 unsigned char B; |
| 29 unsigned int C; |
| 30 unsigned int A; |
| 31 unsigned int CT; |
| 32 CJBig2_BitStream* m_pStream; |
| 33 }; |
| 34 inline CJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream* pStream) { |
| 35 m_pStream = pStream; |
| 36 INITDEC(); |
| 37 } |
| 38 inline CJBig2_ArithDecoder::~CJBig2_ArithDecoder() {} |
| 39 inline void CJBig2_ArithDecoder::INITDEC() { |
| 40 B = m_pStream->getCurByte_arith(); |
| 41 C = (B ^ 0xff) << 16; |
| 42 ; |
| 43 BYTEIN(); |
| 44 C = C << 7; |
| 45 CT = CT - 7; |
| 46 A = 0x8000; |
| 47 } |
| 48 inline void CJBig2_ArithDecoder::BYTEIN() { |
| 49 unsigned char B1; |
| 50 if (B == 0xff) { |
| 51 B1 = m_pStream->getNextByte_arith(); |
| 52 if (B1 > 0x8f) { |
| 53 CT = 8; |
| 54 } else { |
| 55 m_pStream->incByteIdx(); |
| 56 B = B1; |
| 57 C = C + 0xfe00 - (B << 9); |
| 58 CT = 7; |
| 59 } |
| 60 } else { |
| 61 m_pStream->incByteIdx(); |
| 62 B = m_pStream->getCurByte_arith(); |
| 63 C = C + 0xff00 - (B << 8); |
| 64 CT = 8; |
| 65 } |
| 66 } |
| 67 inline int CJBig2_ArithDecoder::DECODE(JBig2ArithCtx* pCX) { |
| 68 if (!pCX || pCX->I >= JBIG2_QE_NUM) { |
| 69 return 0; |
| 70 } |
| 28 | 71 |
| 29 void BYTEIN(); | 72 int D; |
| 30 unsigned char B; | 73 const JBig2ArithQe* qe = &QeTable[pCX->I]; |
| 31 unsigned int C; | 74 A = A - qe->Qe; |
| 32 unsigned int A; | 75 if ((C >> 16) < A) { |
| 33 unsigned int CT; | 76 if (A & 0x8000) { |
| 34 CJBig2_BitStream *m_pStream; | 77 D = pCX->MPS; |
| 35 }; | 78 } else { |
| 36 inline CJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream *pStream) | 79 if (A < qe->Qe) { |
| 37 { | 80 D = 1 - pCX->MPS; |
| 38 m_pStream = pStream; | 81 if (qe->nSwitch == 1) { |
| 39 INITDEC(); | 82 pCX->MPS = 1 - pCX->MPS; |
| 40 } | |
| 41 inline CJBig2_ArithDecoder::~CJBig2_ArithDecoder() | |
| 42 { | |
| 43 } | |
| 44 inline void CJBig2_ArithDecoder::INITDEC() | |
| 45 { | |
| 46 B = m_pStream->getCurByte_arith(); | |
| 47 C = (B ^ 0xff) << 16;; | |
| 48 BYTEIN(); | |
| 49 C = C << 7; | |
| 50 CT = CT - 7; | |
| 51 A = 0x8000; | |
| 52 } | |
| 53 inline void CJBig2_ArithDecoder::BYTEIN() | |
| 54 { | |
| 55 unsigned char B1; | |
| 56 if(B == 0xff) { | |
| 57 B1 = m_pStream->getNextByte_arith(); | |
| 58 if(B1 > 0x8f) { | |
| 59 CT = 8; | |
| 60 } else { | |
| 61 m_pStream->incByteIdx(); | |
| 62 B = B1; | |
| 63 C = C + 0xfe00 - (B << 9); | |
| 64 CT = 7; | |
| 65 } | 83 } |
| 84 pCX->I = qe->NLPS; |
| 85 } else { |
| 86 D = pCX->MPS; |
| 87 pCX->I = qe->NMPS; |
| 88 } |
| 89 do { |
| 90 if (CT == 0) { |
| 91 BYTEIN(); |
| 92 } |
| 93 A <<= 1; |
| 94 C <<= 1; |
| 95 CT--; |
| 96 } while ((A & 0x8000) == 0); |
| 97 } |
| 98 } else { |
| 99 C -= A << 16; |
| 100 if (A < qe->Qe) { |
| 101 A = qe->Qe; |
| 102 D = pCX->MPS; |
| 103 pCX->I = qe->NMPS; |
| 66 } else { | 104 } else { |
| 67 m_pStream->incByteIdx(); | 105 A = qe->Qe; |
| 68 B = m_pStream->getCurByte_arith(); | 106 D = 1 - pCX->MPS; |
| 69 C = C + 0xff00 - (B << 8); | 107 if (qe->nSwitch == 1) { |
| 70 CT = 8; | 108 pCX->MPS = 1 - pCX->MPS; |
| 109 } |
| 110 pCX->I = qe->NLPS; |
| 71 } | 111 } |
| 72 } | 112 do { |
| 73 inline int CJBig2_ArithDecoder::DECODE(JBig2ArithCtx *pCX) | 113 if (CT == 0) { |
| 74 { | 114 BYTEIN(); |
| 75 if (!pCX || pCX->I >= JBIG2_QE_NUM) { | 115 } |
| 76 return 0; | 116 A <<= 1; |
| 77 } | 117 C <<= 1; |
| 78 | 118 CT--; |
| 79 int D; | 119 } while ((A & 0x8000) == 0); |
| 80 const JBig2ArithQe * qe = &QeTable[pCX->I]; | 120 } |
| 81 A = A - qe->Qe; | 121 return D; |
| 82 if((C >> 16) < A) { | |
| 83 if(A & 0x8000) { | |
| 84 D = pCX->MPS; | |
| 85 } else { | |
| 86 if(A < qe->Qe) { | |
| 87 D = 1 - pCX->MPS; | |
| 88 if(qe->nSwitch == 1) { | |
| 89 pCX->MPS = 1 - pCX->MPS; | |
| 90 } | |
| 91 pCX->I = qe->NLPS; | |
| 92 } else { | |
| 93 D = pCX->MPS; | |
| 94 pCX->I = qe->NMPS; | |
| 95 } | |
| 96 do { | |
| 97 if (CT == 0) { | |
| 98 BYTEIN(); | |
| 99 } | |
| 100 A <<= 1; | |
| 101 C <<= 1; | |
| 102 CT--; | |
| 103 } while ((A & 0x8000) == 0); | |
| 104 } | |
| 105 } else { | |
| 106 C -= A << 16; | |
| 107 if(A < qe->Qe) { | |
| 108 A = qe->Qe; | |
| 109 D = pCX->MPS; | |
| 110 pCX->I = qe->NMPS; | |
| 111 } else { | |
| 112 A = qe->Qe; | |
| 113 D = 1 - pCX->MPS; | |
| 114 if(qe->nSwitch == 1) { | |
| 115 pCX->MPS = 1 - pCX->MPS; | |
| 116 } | |
| 117 pCX->I = qe->NLPS; | |
| 118 } | |
| 119 do { | |
| 120 if (CT == 0) { | |
| 121 BYTEIN(); | |
| 122 } | |
| 123 A <<= 1; | |
| 124 C <<= 1; | |
| 125 CT--; | |
| 126 } while ((A & 0x8000) == 0); | |
| 127 } | |
| 128 return D; | |
| 129 } | 122 } |
| 130 #endif | 123 #endif |
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