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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 #include "core/src/fxcodec/jbig2/JBig2_ArithDecoder.h" | 7 #include "core/fxcodec/jbig2/JBig2_ArithDecoder.h" |
8 | 8 |
| 9 #include "core/fxcodec/jbig2/JBig2_BitStream.h" |
9 #include "core/include/fxcrt/fx_basic.h" | 10 #include "core/include/fxcrt/fx_basic.h" |
10 #include "core/src/fxcodec/jbig2/JBig2_BitStream.h" | |
11 | 11 |
12 namespace { | 12 namespace { |
13 | 13 |
14 struct JBig2ArithQe { | 14 struct JBig2ArithQe { |
15 unsigned int Qe; | 15 unsigned int Qe; |
16 unsigned int NMPS; | 16 unsigned int NMPS; |
17 unsigned int NLPS; | 17 unsigned int NLPS; |
18 unsigned int nSwitch; | 18 unsigned int nSwitch; |
19 }; | 19 }; |
20 | 20 |
21 const JBig2ArithQe kQeTable[] = { | 21 const JBig2ArithQe kQeTable[] = { |
22 // Stupid hack to keep clang-format from reformatting this badly. | 22 // Stupid hack to keep clang-format from reformatting this badly. |
23 {0x5601, 1, 1, 1}, | 23 {0x5601, 1, 1, 1}, {0x3401, 2, 6, 0}, {0x1801, 3, 9, 0}, |
24 {0x3401, 2, 6, 0}, | 24 {0x0AC1, 4, 12, 0}, {0x0521, 5, 29, 0}, {0x0221, 38, 33, 0}, |
25 {0x1801, 3, 9, 0}, | 25 {0x5601, 7, 6, 1}, {0x5401, 8, 14, 0}, {0x4801, 9, 14, 0}, |
26 {0x0AC1, 4, 12, 0}, | 26 {0x3801, 10, 14, 0}, {0x3001, 11, 17, 0}, {0x2401, 12, 18, 0}, |
27 {0x0521, 5, 29, 0}, | 27 {0x1C01, 13, 20, 0}, {0x1601, 29, 21, 0}, {0x5601, 15, 14, 1}, |
28 {0x0221, 38, 33, 0}, | 28 {0x5401, 16, 14, 0}, {0x5101, 17, 15, 0}, {0x4801, 18, 16, 0}, |
29 {0x5601, 7, 6, 1}, | 29 {0x3801, 19, 17, 0}, {0x3401, 20, 18, 0}, {0x3001, 21, 19, 0}, |
30 {0x5401, 8, 14, 0}, | 30 {0x2801, 22, 19, 0}, {0x2401, 23, 20, 0}, {0x2201, 24, 21, 0}, |
31 {0x4801, 9, 14, 0}, | 31 {0x1C01, 25, 22, 0}, {0x1801, 26, 23, 0}, {0x1601, 27, 24, 0}, |
32 {0x3801, 10, 14, 0}, | 32 {0x1401, 28, 25, 0}, {0x1201, 29, 26, 0}, {0x1101, 30, 27, 0}, |
33 {0x3001, 11, 17, 0}, | 33 {0x0AC1, 31, 28, 0}, {0x09C1, 32, 29, 0}, {0x08A1, 33, 30, 0}, |
34 {0x2401, 12, 18, 0}, | 34 {0x0521, 34, 31, 0}, {0x0441, 35, 32, 0}, {0x02A1, 36, 33, 0}, |
35 {0x1C01, 13, 20, 0}, | 35 {0x0221, 37, 34, 0}, {0x0141, 38, 35, 0}, {0x0111, 39, 36, 0}, |
36 {0x1601, 29, 21, 0}, | 36 {0x0085, 40, 37, 0}, {0x0049, 41, 38, 0}, {0x0025, 42, 39, 0}, |
37 {0x5601, 15, 14, 1}, | 37 {0x0015, 43, 40, 0}, {0x0009, 44, 41, 0}, {0x0005, 45, 42, 0}, |
38 {0x5401, 16, 14, 0}, | 38 {0x0001, 45, 43, 0}, {0x5601, 46, 46, 0}}; |
39 {0x5101, 17, 15, 0}, | |
40 {0x4801, 18, 16, 0}, | |
41 {0x3801, 19, 17, 0}, | |
42 {0x3401, 20, 18, 0}, | |
43 {0x3001, 21, 19, 0}, | |
44 {0x2801, 22, 19, 0}, | |
45 {0x2401, 23, 20, 0}, | |
46 {0x2201, 24, 21, 0}, | |
47 {0x1C01, 25, 22, 0}, | |
48 {0x1801, 26, 23, 0}, | |
49 {0x1601, 27, 24, 0}, | |
50 {0x1401, 28, 25, 0}, | |
51 {0x1201, 29, 26, 0}, | |
52 {0x1101, 30, 27, 0}, | |
53 {0x0AC1, 31, 28, 0}, | |
54 {0x09C1, 32, 29, 0}, | |
55 {0x08A1, 33, 30, 0}, | |
56 {0x0521, 34, 31, 0}, | |
57 {0x0441, 35, 32, 0}, | |
58 {0x02A1, 36, 33, 0}, | |
59 {0x0221, 37, 34, 0}, | |
60 {0x0141, 38, 35, 0}, | |
61 {0x0111, 39, 36, 0}, | |
62 {0x0085, 40, 37, 0}, | |
63 {0x0049, 41, 38, 0}, | |
64 {0x0025, 42, 39, 0}, | |
65 {0x0015, 43, 40, 0}, | |
66 {0x0009, 44, 41, 0}, | |
67 {0x0005, 45, 42, 0}, | |
68 {0x0001, 45, 43, 0}, | |
69 {0x5601, 46, 46, 0}}; | |
70 | 39 |
71 const unsigned int kDefaultAValue = 0x8000; | 40 const unsigned int kDefaultAValue = 0x8000; |
72 | 41 |
73 int DecodeNMPS(JBig2ArithCtx* pCX, const JBig2ArithQe& qe) { | 42 int DecodeNMPS(JBig2ArithCtx* pCX, const JBig2ArithQe& qe) { |
74 pCX->I = qe.NMPS; | 43 pCX->I = qe.NMPS; |
75 return pCX->MPS; | 44 return pCX->MPS; |
76 } | 45 } |
77 | 46 |
78 int DecodeNLPS(JBig2ArithCtx* pCX, const JBig2ArithQe& qe) { | 47 int DecodeNLPS(JBig2ArithCtx* pCX, const JBig2ArithQe& qe) { |
79 // TODO(thestig): |D|, |MPS| and friends probably should be booleans. | 48 // TODO(thestig): |D|, |MPS| and friends probably should be booleans. |
80 int D = 1 - pCX->MPS; | 49 int D = 1 - pCX->MPS; |
81 if (qe.nSwitch == 1) | 50 if (qe.nSwitch == 1) |
82 pCX->MPS = 1 - pCX->MPS; | 51 pCX->MPS = 1 - pCX->MPS; |
83 pCX->I = qe.NLPS; | 52 pCX->I = qe.NLPS; |
84 return D; | 53 return D; |
85 } | 54 } |
86 | 55 |
87 } // namespace | 56 } // namespace |
88 | 57 |
89 CJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream* pStream) | 58 CJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream* pStream) |
90 : m_pStream(pStream) { | 59 : m_pStream(pStream) { |
91 m_B = m_pStream->getCurByte_arith(); | 60 m_B = m_pStream->getCurByte_arith(); |
92 m_C = (m_B ^ 0xff) << 16; | 61 m_C = (m_B ^ 0xff) << 16; |
93 BYTEIN(); | 62 BYTEIN(); |
94 m_C = m_C << 7; | 63 m_C = m_C << 7; |
95 m_CT = m_CT - 7; | 64 m_CT = m_CT - 7; |
96 m_A = kDefaultAValue; | 65 m_A = kDefaultAValue; |
97 } | 66 } |
98 | 67 |
99 CJBig2_ArithDecoder::~CJBig2_ArithDecoder() { | 68 CJBig2_ArithDecoder::~CJBig2_ArithDecoder() {} |
100 } | |
101 | 69 |
102 int CJBig2_ArithDecoder::DECODE(JBig2ArithCtx* pCX) { | 70 int CJBig2_ArithDecoder::DECODE(JBig2ArithCtx* pCX) { |
103 if (!pCX || pCX->I >= FX_ArraySize(kQeTable)) | 71 if (!pCX || pCX->I >= FX_ArraySize(kQeTable)) |
104 return 0; | 72 return 0; |
105 | 73 |
106 const JBig2ArithQe& qe = kQeTable[pCX->I]; | 74 const JBig2ArithQe& qe = kQeTable[pCX->I]; |
107 m_A -= qe.Qe; | 75 m_A -= qe.Qe; |
108 if ((m_C >> 16) < m_A) { | 76 if ((m_C >> 16) < m_A) { |
109 if (m_A & kDefaultAValue) | 77 if (m_A & kDefaultAValue) |
110 return pCX->MPS; | 78 return pCX->MPS; |
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143 | 111 |
144 void CJBig2_ArithDecoder::ReadValueA() { | 112 void CJBig2_ArithDecoder::ReadValueA() { |
145 do { | 113 do { |
146 if (m_CT == 0) | 114 if (m_CT == 0) |
147 BYTEIN(); | 115 BYTEIN(); |
148 m_A <<= 1; | 116 m_A <<= 1; |
149 m_C <<= 1; | 117 m_C <<= 1; |
150 --m_CT; | 118 --m_CT; |
151 } while ((m_A & kDefaultAValue) == 0); | 119 } while ((m_A & kDefaultAValue) == 0); |
152 } | 120 } |
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