diff options
author | Lei Zhang <thestig@chromium.org> | 2015-09-29 21:14:58 -0700 |
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committer | Lei Zhang <thestig@chromium.org> | 2015-09-29 21:14:58 -0700 |
commit | 0fef7dd405ac85660dbeddd2e47620daffa70cb5 (patch) | |
tree | 10e8c9122c39cde5df6eb18214e95854e6f0cba8 /core/src/fxcodec | |
parent | 09939faa51e5b57088756838f4a4db6e01c6ed40 (diff) | |
download | pdfium-0fef7dd405ac85660dbeddd2e47620daffa70cb5.tar.xz |
Cleanup CJBig2_ArithDecoder.
R=tsepez@chromium.org
Review URL: https://codereview.chromium.org/1368153003 .
Diffstat (limited to 'core/src/fxcodec')
-rw-r--r-- | core/src/fxcodec/jbig2/JBig2_ArithDecoder.cpp | 128 | ||||
-rw-r--r-- | core/src/fxcodec/jbig2/JBig2_ArithDecoder.h | 12 |
2 files changed, 63 insertions, 77 deletions
diff --git a/core/src/fxcodec/jbig2/JBig2_ArithDecoder.cpp b/core/src/fxcodec/jbig2/JBig2_ArithDecoder.cpp index 34c79f9fa3..a1aa5bf8a9 100644 --- a/core/src/fxcodec/jbig2/JBig2_ArithDecoder.cpp +++ b/core/src/fxcodec/jbig2/JBig2_ArithDecoder.cpp @@ -8,7 +8,6 @@ #include "../../../include/fxcrt/fx_basic.h" #include "JBig2_BitStream.h" -#include "JBig2_Define.h" namespace { @@ -69,98 +68,85 @@ const JBig2ArithQe kQeTable[] = { {0x0001, 45, 43, 0}, {0x5601, 46, 46, 0}}; +const unsigned int kDefaultAValue = 0x8000; + +int DecodeNMPS(JBig2ArithCtx* pCX, const JBig2ArithQe& qe) { + pCX->I = qe.NMPS; + return pCX->MPS; +} + +int DecodeNLPS(JBig2ArithCtx* pCX, const JBig2ArithQe& qe) { + // TODO(thestig): |D|, |MPS| and friends probably should be booleans. + int D = 1 - pCX->MPS; + if (qe.nSwitch == 1) + pCX->MPS = 1 - pCX->MPS; + pCX->I = qe.NLPS; + return D; +} + } // namespace -CJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream* pStream) { - m_pStream = pStream; - INITDEC(); +CJBig2_ArithDecoder::CJBig2_ArithDecoder(CJBig2_BitStream* pStream) + : m_pStream(pStream) { + m_B = m_pStream->getCurByte_arith(); + m_C = (m_B ^ 0xff) << 16; + BYTEIN(); + m_C = m_C << 7; + m_CT = m_CT - 7; + m_A = kDefaultAValue; } CJBig2_ArithDecoder::~CJBig2_ArithDecoder() { } int CJBig2_ArithDecoder::DECODE(JBig2ArithCtx* pCX) { - if (!pCX || pCX->I >= FX_ArraySize(kQeTable)) { + if (!pCX || pCX->I >= FX_ArraySize(kQeTable)) return 0; - } - int D; - const JBig2ArithQe* qe = &kQeTable[pCX->I]; - A = A - qe->Qe; - if ((C >> 16) < A) { - if (A & 0x8000) { - D = pCX->MPS; - } else { - if (A < qe->Qe) { - D = 1 - pCX->MPS; - if (qe->nSwitch == 1) { - pCX->MPS = 1 - pCX->MPS; - } - pCX->I = qe->NLPS; - } else { - D = pCX->MPS; - pCX->I = qe->NMPS; - } - do { - if (CT == 0) { - BYTEIN(); - } - A <<= 1; - C <<= 1; - CT--; - } while ((A & 0x8000) == 0); - } - } else { - C -= A << 16; - if (A < qe->Qe) { - A = qe->Qe; - D = pCX->MPS; - pCX->I = qe->NMPS; - } else { - A = qe->Qe; - D = 1 - pCX->MPS; - if (qe->nSwitch == 1) { - pCX->MPS = 1 - pCX->MPS; - } - pCX->I = qe->NLPS; - } - do { - if (CT == 0) { - BYTEIN(); - } - A <<= 1; - C <<= 1; - CT--; - } while ((A & 0x8000) == 0); + const JBig2ArithQe& qe = kQeTable[pCX->I]; + m_A -= qe.Qe; + if ((m_C >> 16) < m_A) { + if (m_A & kDefaultAValue) + return pCX->MPS; + + const int D = m_A < qe.Qe ? DecodeNLPS(pCX, qe) : DecodeNMPS(pCX, qe); + ReadValueA(); + return D; } - return D; -} -void CJBig2_ArithDecoder::INITDEC() { - B = m_pStream->getCurByte_arith(); - C = (B ^ 0xff) << 16; - BYTEIN(); - C = C << 7; - CT = CT - 7; - A = 0x8000; + m_C -= m_A << 16; + const int D = m_A < qe.Qe ? DecodeNMPS(pCX, qe) : DecodeNLPS(pCX, qe); + m_A = qe.Qe; + ReadValueA(); + return D; } void CJBig2_ArithDecoder::BYTEIN() { unsigned char B1; - if (B == 0xff) { + if (m_B == 0xff) { B1 = m_pStream->getNextByte_arith(); if (B1 > 0x8f) { - CT = 8; + m_CT = 8; } else { m_pStream->incByteIdx(); - B = B1; - C = C + 0xfe00 - (B << 9); - CT = 7; + m_B = B1; + m_C = m_C + 0xfe00 - (m_B << 9); + m_CT = 7; } } else { m_pStream->incByteIdx(); - B = m_pStream->getCurByte_arith(); - C = C + 0xff00 - (B << 8); - CT = 8; + m_B = m_pStream->getCurByte_arith(); + m_C = m_C + 0xff00 - (m_B << 8); + m_CT = 8; } } + +void CJBig2_ArithDecoder::ReadValueA() { + do { + if (m_CT == 0) + BYTEIN(); + m_A <<= 1; + m_C <<= 1; + --m_CT; + } while ((m_A & kDefaultAValue) == 0); +} diff --git a/core/src/fxcodec/jbig2/JBig2_ArithDecoder.h b/core/src/fxcodec/jbig2/JBig2_ArithDecoder.h index 02c81b34c0..a1e891065c 100644 --- a/core/src/fxcodec/jbig2/JBig2_ArithDecoder.h +++ b/core/src/fxcodec/jbig2/JBig2_ArithDecoder.h @@ -23,14 +23,14 @@ class CJBig2_ArithDecoder { int DECODE(JBig2ArithCtx* pCX); private: - void INITDEC(); void BYTEIN(); + void ReadValueA(); - unsigned char B; - unsigned int C; - unsigned int A; - unsigned int CT; - CJBig2_BitStream* m_pStream; + unsigned char m_B; + unsigned int m_C; + unsigned int m_A; + unsigned int m_CT; + CJBig2_BitStream* const m_pStream; }; #endif // CORE_SRC_FXCODEC_JBIG2_JBIG2_ARITHDECODER_H_ |