From b060a551917627e3436bfb0a2a5c7a08cb5c58af Mon Sep 17 00:00:00 2001
From: Lei Zhang <thestig@chromium.org>
Date: Thu, 24 Sep 2015 01:13:26 -0700
Subject: Merge to XFA: Split up JBig2_GeneralDecoder.cpp.

TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1359233002 .

(cherry picked from commit 630a28442364f03c1d3d9b48873da42755e1fddf)

Review URL: https://codereview.chromium.org/1364083004 .
---
 core/src/fxcodec/jbig2/JBig2_GrrdProc.cpp | 515 ++++++++++++++++++++++++++++++
 1 file changed, 515 insertions(+)
 create mode 100644 core/src/fxcodec/jbig2/JBig2_GrrdProc.cpp

(limited to 'core/src/fxcodec/jbig2/JBig2_GrrdProc.cpp')

diff --git a/core/src/fxcodec/jbig2/JBig2_GrrdProc.cpp b/core/src/fxcodec/jbig2/JBig2_GrrdProc.cpp
new file mode 100644
index 0000000000..916683c8aa
--- /dev/null
+++ b/core/src/fxcodec/jbig2/JBig2_GrrdProc.cpp
@@ -0,0 +1,515 @@
+// Copyright 2015 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
+
+#include "JBig2_GrrdProc.h"
+
+#include "../../../../third_party/base/nonstd_unique_ptr.h"
+#include "JBig2_ArithDecoder.h"
+#include "JBig2_BitStream.h"
+#include "JBig2_Image.h"
+
+CJBig2_Image* CJBig2_GRRDProc::decode(CJBig2_ArithDecoder* pArithDecoder,
+                                      JBig2ArithCtx* grContext) {
+  if (GRW == 0 || GRH == 0)
+    return new CJBig2_Image(GRW, GRH);
+
+  if (GRTEMPLATE == 0) {
+    if ((GRAT[0] == -1) && (GRAT[1] == -1) && (GRAT[2] == -1) &&
+        (GRAT[3] == -1) && (GRREFERENCEDX == 0) &&
+        (GRW == (FX_DWORD)GRREFERENCE->m_nWidth)) {
+      return decode_Template0_opt(pArithDecoder, grContext);
+    }
+    return decode_Template0_unopt(pArithDecoder, grContext);
+  }
+
+  if ((GRREFERENCEDX == 0) && (GRW == (FX_DWORD)GRREFERENCE->m_nWidth))
+    return decode_Template1_opt(pArithDecoder, grContext);
+  return decode_Template1_unopt(pArithDecoder, grContext);
+}
+
+CJBig2_Image* CJBig2_GRRDProc::decode_Template0_unopt(
+    CJBig2_ArithDecoder* pArithDecoder,
+    JBig2ArithCtx* grContext) {
+  FX_BOOL LTP, SLTP, bVal;
+  FX_DWORD CONTEXT;
+  FX_DWORD line1, line2, line3, line4, line5;
+  LTP = 0;
+  nonstd::unique_ptr<CJBig2_Image> GRREG(new CJBig2_Image(GRW, GRH));
+  GRREG->fill(0);
+  for (FX_DWORD h = 0; h < GRH; h++) {
+    if (TPGRON) {
+      SLTP = pArithDecoder->DECODE(&grContext[0x0010]);
+      LTP = LTP ^ SLTP;
+    }
+    if (LTP == 0) {
+      line1 = GRREG->getPixel(1, h - 1);
+      line1 |= GRREG->getPixel(0, h - 1) << 1;
+      line2 = 0;
+      line3 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY - 1);
+      line3 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY - 1)
+               << 1;
+      line4 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY);
+      line4 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY) << 1;
+      line4 |= GRREFERENCE->getPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY)
+               << 2;
+      line5 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY + 1);
+      line5 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY + 1)
+               << 1;
+      line5 |= GRREFERENCE->getPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY + 1)
+               << 2;
+      for (FX_DWORD w = 0; w < GRW; w++) {
+        CONTEXT = line5;
+        CONTEXT |= line4 << 3;
+        CONTEXT |= line3 << 6;
+        CONTEXT |= GRREFERENCE->getPixel(w - GRREFERENCEDX + GRAT[2],
+                                         h - GRREFERENCEDY + GRAT[3])
+                   << 8;
+        CONTEXT |= line2 << 9;
+        CONTEXT |= line1 << 10;
+        CONTEXT |= GRREG->getPixel(w + GRAT[0], h + GRAT[1]) << 12;
+        bVal = pArithDecoder->DECODE(&grContext[CONTEXT]);
+        GRREG->setPixel(w, h, bVal);
+        line1 = ((line1 << 1) | GRREG->getPixel(w + 2, h - 1)) & 0x03;
+        line2 = ((line2 << 1) | bVal) & 0x01;
+        line3 = ((line3 << 1) |
+                 GRREFERENCE->getPixel(w - GRREFERENCEDX + 2,
+                                       h - GRREFERENCEDY - 1)) &
+                0x03;
+        line4 =
+            ((line4 << 1) |
+             GRREFERENCE->getPixel(w - GRREFERENCEDX + 2, h - GRREFERENCEDY)) &
+            0x07;
+        line5 = ((line5 << 1) |
+                 GRREFERENCE->getPixel(w - GRREFERENCEDX + 2,
+                                       h - GRREFERENCEDY + 1)) &
+                0x07;
+      }
+    } else {
+      line1 = GRREG->getPixel(1, h - 1);
+      line1 |= GRREG->getPixel(0, h - 1) << 1;
+      line2 = 0;
+      line3 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY - 1);
+      line3 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY - 1)
+               << 1;
+      line4 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY);
+      line4 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY) << 1;
+      line4 |= GRREFERENCE->getPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY)
+               << 2;
+      line5 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY + 1);
+      line5 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY + 1)
+               << 1;
+      line5 |= GRREFERENCE->getPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY + 1)
+               << 2;
+      for (FX_DWORD w = 0; w < GRW; w++) {
+        bVal = GRREFERENCE->getPixel(w, h);
+        if (!(TPGRON && (bVal == GRREFERENCE->getPixel(w - 1, h - 1)) &&
+              (bVal == GRREFERENCE->getPixel(w, h - 1)) &&
+              (bVal == GRREFERENCE->getPixel(w + 1, h - 1)) &&
+              (bVal == GRREFERENCE->getPixel(w - 1, h)) &&
+              (bVal == GRREFERENCE->getPixel(w + 1, h)) &&
+              (bVal == GRREFERENCE->getPixel(w - 1, h + 1)) &&
+              (bVal == GRREFERENCE->getPixel(w, h + 1)) &&
+              (bVal == GRREFERENCE->getPixel(w + 1, h + 1)))) {
+          CONTEXT = line5;
+          CONTEXT |= line4 << 3;
+          CONTEXT |= line3 << 6;
+          CONTEXT |= GRREFERENCE->getPixel(w - GRREFERENCEDX + GRAT[2],
+                                           h - GRREFERENCEDY + GRAT[3])
+                     << 8;
+          CONTEXT |= line2 << 9;
+          CONTEXT |= line1 << 10;
+          CONTEXT |= GRREG->getPixel(w + GRAT[0], h + GRAT[1]) << 12;
+          bVal = pArithDecoder->DECODE(&grContext[CONTEXT]);
+        }
+        GRREG->setPixel(w, h, bVal);
+        line1 = ((line1 << 1) | GRREG->getPixel(w + 2, h - 1)) & 0x03;
+        line2 = ((line2 << 1) | bVal) & 0x01;
+        line3 = ((line3 << 1) |
+                 GRREFERENCE->getPixel(w - GRREFERENCEDX + 2,
+                                       h - GRREFERENCEDY - 1)) &
+                0x03;
+        line4 =
+            ((line4 << 1) |
+             GRREFERENCE->getPixel(w - GRREFERENCEDX + 2, h - GRREFERENCEDY)) &
+            0x07;
+        line5 = ((line5 << 1) |
+                 GRREFERENCE->getPixel(w - GRREFERENCEDX + 2,
+                                       h - GRREFERENCEDY + 1)) &
+                0x07;
+      }
+    }
+  }
+  return GRREG.release();
+}
+
+CJBig2_Image* CJBig2_GRRDProc::decode_Template0_opt(
+    CJBig2_ArithDecoder* pArithDecoder,
+    JBig2ArithCtx* grContext) {
+  if (!GRREFERENCE->m_pData)
+    return nullptr;
+
+  FX_BOOL LTP, SLTP, bVal;
+  FX_DWORD CONTEXT;
+  FX_DWORD line1, line1_r, line2_r, line3_r;
+  uint8_t* pLine, *pLineR, cVal;
+  intptr_t nStride, nStrideR, nOffset;
+  int32_t k, nBits;
+  int32_t GRWR, GRHR;
+  int32_t GRW, GRH;
+  GRW = (int32_t)CJBig2_GRRDProc::GRW;
+  GRH = (int32_t)CJBig2_GRRDProc::GRH;
+  LTP = 0;
+  nonstd::unique_ptr<CJBig2_Image> GRREG(new CJBig2_Image(GRW, GRH));
+  if (!GRREG->m_pData)
+    return nullptr;
+
+  pLine = GRREG->m_pData;
+  pLineR = GRREFERENCE->m_pData;
+  nStride = GRREG->m_nStride;
+  nStrideR = GRREFERENCE->m_nStride;
+  GRWR = (int32_t)GRREFERENCE->m_nWidth;
+  GRHR = (int32_t)GRREFERENCE->m_nHeight;
+  if (GRREFERENCEDY < -GRHR + 1 || GRREFERENCEDY > GRHR - 1) {
+    GRREFERENCEDY = 0;
+  }
+  nOffset = -GRREFERENCEDY * nStrideR;
+  for (int32_t h = 0; h < GRH; h++) {
+    if (TPGRON) {
+      SLTP = pArithDecoder->DECODE(&grContext[0x0010]);
+      LTP = LTP ^ SLTP;
+    }
+    line1 = (h > 0) ? pLine[-nStride] << 4 : 0;
+    int32_t reference_h = h - GRREFERENCEDY;
+    FX_BOOL line1_r_ok = (reference_h > 0 && reference_h < GRHR + 1);
+    FX_BOOL line2_r_ok = (reference_h > -1 && reference_h < GRHR);
+    FX_BOOL line3_r_ok = (reference_h > -2 && reference_h < GRHR - 1);
+    line1_r = line1_r_ok ? pLineR[nOffset - nStrideR] : 0;
+    line2_r = line2_r_ok ? pLineR[nOffset] : 0;
+    line3_r = line3_r_ok ? pLineR[nOffset + nStrideR] : 0;
+    if (LTP == 0) {
+      CONTEXT = (line1 & 0x1c00) | (line1_r & 0x01c0) |
+                ((line2_r >> 3) & 0x0038) | ((line3_r >> 6) & 0x0007);
+      for (int32_t w = 0; w < GRW; w += 8) {
+        nBits = GRW - w > 8 ? 8 : GRW - w;
+        if (h > 0)
+          line1 = (line1 << 8) |
+                  (w + 8 < GRW ? pLine[-nStride + (w >> 3) + 1] << 4 : 0);
+        if (h > GRHR + GRREFERENCEDY + 1) {
+          line1_r = 0;
+          line2_r = 0;
+          line3_r = 0;
+        } else {
+          if (line1_r_ok)
+            line1_r =
+                (line1_r << 8) |
+                (w + 8 < GRWR ? pLineR[nOffset - nStrideR + (w >> 3) + 1] : 0);
+          if (line2_r_ok)
+            line2_r = (line2_r << 8) |
+                      (w + 8 < GRWR ? pLineR[nOffset + (w >> 3) + 1] : 0);
+          if (line3_r_ok) {
+            line3_r =
+                (line3_r << 8) |
+                (w + 8 < GRWR ? pLineR[nOffset + nStrideR + (w >> 3) + 1] : 0);
+          } else {
+            line3_r = 0;
+          }
+        }
+        cVal = 0;
+        for (k = 0; k < nBits; k++) {
+          bVal = pArithDecoder->DECODE(&grContext[CONTEXT]);
+          cVal |= bVal << (7 - k);
+          CONTEXT = ((CONTEXT & 0x0cdb) << 1) | (bVal << 9) |
+                    ((line1 >> (7 - k)) & 0x0400) |
+                    ((line1_r >> (7 - k)) & 0x0040) |
+                    ((line2_r >> (10 - k)) & 0x0008) |
+                    ((line3_r >> (13 - k)) & 0x0001);
+        }
+        pLine[w >> 3] = cVal;
+      }
+    } else {
+      CONTEXT = (line1 & 0x1c00) | (line1_r & 0x01c0) |
+                ((line2_r >> 3) & 0x0038) | ((line3_r >> 6) & 0x0007);
+      for (int32_t w = 0; w < GRW; w += 8) {
+        nBits = GRW - w > 8 ? 8 : GRW - w;
+        if (h > 0)
+          line1 = (line1 << 8) |
+                  (w + 8 < GRW ? pLine[-nStride + (w >> 3) + 1] << 4 : 0);
+        if (line1_r_ok)
+          line1_r =
+              (line1_r << 8) |
+              (w + 8 < GRWR ? pLineR[nOffset - nStrideR + (w >> 3) + 1] : 0);
+        if (line2_r_ok)
+          line2_r = (line2_r << 8) |
+                    (w + 8 < GRWR ? pLineR[nOffset + (w >> 3) + 1] : 0);
+        if (line3_r_ok) {
+          line3_r =
+              (line3_r << 8) |
+              (w + 8 < GRWR ? pLineR[nOffset + nStrideR + (w >> 3) + 1] : 0);
+        } else {
+          line3_r = 0;
+        }
+        cVal = 0;
+        for (k = 0; k < nBits; k++) {
+          bVal = GRREFERENCE->getPixel(w + k, h);
+          if (!(TPGRON && (bVal == GRREFERENCE->getPixel(w + k - 1, h - 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k, h - 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k + 1, h - 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k - 1, h)) &&
+                (bVal == GRREFERENCE->getPixel(w + k + 1, h)) &&
+                (bVal == GRREFERENCE->getPixel(w + k - 1, h + 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k, h + 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k + 1, h + 1)))) {
+            bVal = pArithDecoder->DECODE(&grContext[CONTEXT]);
+          }
+          cVal |= bVal << (7 - k);
+          CONTEXT = ((CONTEXT & 0x0cdb) << 1) | (bVal << 9) |
+                    ((line1 >> (7 - k)) & 0x0400) |
+                    ((line1_r >> (7 - k)) & 0x0040) |
+                    ((line2_r >> (10 - k)) & 0x0008) |
+                    ((line3_r >> (13 - k)) & 0x0001);
+        }
+        pLine[w >> 3] = cVal;
+      }
+    }
+    pLine += nStride;
+    if (h < GRHR + GRREFERENCEDY) {
+      pLineR += nStrideR;
+    }
+  }
+  return GRREG.release();
+}
+
+CJBig2_Image* CJBig2_GRRDProc::decode_Template1_unopt(
+    CJBig2_ArithDecoder* pArithDecoder,
+    JBig2ArithCtx* grContext) {
+  FX_BOOL LTP, SLTP, bVal;
+  FX_DWORD CONTEXT;
+  FX_DWORD line1, line2, line3, line4, line5;
+  LTP = 0;
+  nonstd::unique_ptr<CJBig2_Image> GRREG(new CJBig2_Image(GRW, GRH));
+  GRREG->fill(0);
+  for (FX_DWORD h = 0; h < GRH; h++) {
+    if (TPGRON) {
+      SLTP = pArithDecoder->DECODE(&grContext[0x0008]);
+      LTP = LTP ^ SLTP;
+    }
+    if (LTP == 0) {
+      line1 = GRREG->getPixel(1, h - 1);
+      line1 |= GRREG->getPixel(0, h - 1) << 1;
+      line1 |= GRREG->getPixel(-1, h - 1) << 2;
+      line2 = 0;
+      line3 = GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY - 1);
+      line4 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY);
+      line4 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY) << 1;
+      line4 |= GRREFERENCE->getPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY)
+               << 2;
+      line5 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY + 1);
+      line5 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY + 1)
+               << 1;
+      for (FX_DWORD w = 0; w < GRW; w++) {
+        CONTEXT = line5;
+        CONTEXT |= line4 << 2;
+        CONTEXT |= line3 << 5;
+        CONTEXT |= line2 << 6;
+        CONTEXT |= line1 << 7;
+        bVal = pArithDecoder->DECODE(&grContext[CONTEXT]);
+        GRREG->setPixel(w, h, bVal);
+        line1 = ((line1 << 1) | GRREG->getPixel(w + 2, h - 1)) & 0x07;
+        line2 = ((line2 << 1) | bVal) & 0x01;
+        line3 = ((line3 << 1) |
+                 GRREFERENCE->getPixel(w - GRREFERENCEDX + 1,
+                                       h - GRREFERENCEDY - 1)) &
+                0x01;
+        line4 =
+            ((line4 << 1) |
+             GRREFERENCE->getPixel(w - GRREFERENCEDX + 2, h - GRREFERENCEDY)) &
+            0x07;
+        line5 = ((line5 << 1) |
+                 GRREFERENCE->getPixel(w - GRREFERENCEDX + 2,
+                                       h - GRREFERENCEDY + 1)) &
+                0x03;
+      }
+    } else {
+      line1 = GRREG->getPixel(1, h - 1);
+      line1 |= GRREG->getPixel(0, h - 1) << 1;
+      line1 |= GRREG->getPixel(-1, h - 1) << 2;
+      line2 = 0;
+      line3 = GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY - 1);
+      line4 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY);
+      line4 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY) << 1;
+      line4 |= GRREFERENCE->getPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY)
+               << 2;
+      line5 = GRREFERENCE->getPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY + 1);
+      line5 |= GRREFERENCE->getPixel(-GRREFERENCEDX, h - GRREFERENCEDY + 1)
+               << 1;
+      for (FX_DWORD w = 0; w < GRW; w++) {
+        bVal = GRREFERENCE->getPixel(w, h);
+        if (!(TPGRON && (bVal == GRREFERENCE->getPixel(w - 1, h - 1)) &&
+              (bVal == GRREFERENCE->getPixel(w, h - 1)) &&
+              (bVal == GRREFERENCE->getPixel(w + 1, h - 1)) &&
+              (bVal == GRREFERENCE->getPixel(w - 1, h)) &&
+              (bVal == GRREFERENCE->getPixel(w + 1, h)) &&
+              (bVal == GRREFERENCE->getPixel(w - 1, h + 1)) &&
+              (bVal == GRREFERENCE->getPixel(w, h + 1)) &&
+              (bVal == GRREFERENCE->getPixel(w + 1, h + 1)))) {
+          CONTEXT = line5;
+          CONTEXT |= line4 << 2;
+          CONTEXT |= line3 << 5;
+          CONTEXT |= line2 << 6;
+          CONTEXT |= line1 << 7;
+          bVal = pArithDecoder->DECODE(&grContext[CONTEXT]);
+        }
+        GRREG->setPixel(w, h, bVal);
+        line1 = ((line1 << 1) | GRREG->getPixel(w + 2, h - 1)) & 0x07;
+        line2 = ((line2 << 1) | bVal) & 0x01;
+        line3 = ((line3 << 1) |
+                 GRREFERENCE->getPixel(w - GRREFERENCEDX + 1,
+                                       h - GRREFERENCEDY - 1)) &
+                0x01;
+        line4 =
+            ((line4 << 1) |
+             GRREFERENCE->getPixel(w - GRREFERENCEDX + 2, h - GRREFERENCEDY)) &
+            0x07;
+        line5 = ((line5 << 1) |
+                 GRREFERENCE->getPixel(w - GRREFERENCEDX + 2,
+                                       h - GRREFERENCEDY + 1)) &
+                0x03;
+      }
+    }
+  }
+  return GRREG.release();
+}
+
+CJBig2_Image* CJBig2_GRRDProc::decode_Template1_opt(
+    CJBig2_ArithDecoder* pArithDecoder,
+    JBig2ArithCtx* grContext) {
+  if (!GRREFERENCE->m_pData)
+    return nullptr;
+
+  FX_BOOL LTP, SLTP, bVal;
+  FX_DWORD CONTEXT;
+  FX_DWORD line1, line1_r, line2_r, line3_r;
+  uint8_t* pLine, *pLineR, cVal;
+  intptr_t nStride, nStrideR, nOffset;
+  int32_t k, nBits;
+  int32_t GRWR, GRHR;
+  int32_t GRW, GRH;
+  GRW = (int32_t)CJBig2_GRRDProc::GRW;
+  GRH = (int32_t)CJBig2_GRRDProc::GRH;
+  LTP = 0;
+  nonstd::unique_ptr<CJBig2_Image> GRREG(new CJBig2_Image(GRW, GRH));
+  if (!GRREG->m_pData)
+    return nullptr;
+
+  pLine = GRREG->m_pData;
+  pLineR = GRREFERENCE->m_pData;
+  nStride = GRREG->m_nStride;
+  nStrideR = GRREFERENCE->m_nStride;
+  GRWR = (int32_t)GRREFERENCE->m_nWidth;
+  GRHR = (int32_t)GRREFERENCE->m_nHeight;
+  if (GRREFERENCEDY < -GRHR + 1 || GRREFERENCEDY > GRHR - 1) {
+    GRREFERENCEDY = 0;
+  }
+  nOffset = -GRREFERENCEDY * nStrideR;
+  for (int32_t h = 0; h < GRH; h++) {
+    if (TPGRON) {
+      SLTP = pArithDecoder->DECODE(&grContext[0x0008]);
+      LTP = LTP ^ SLTP;
+    }
+    line1 = (h > 0) ? pLine[-nStride] << 1 : 0;
+    int32_t reference_h = h - GRREFERENCEDY;
+    FX_BOOL line1_r_ok = (reference_h > 0 && reference_h < GRHR + 1);
+    FX_BOOL line2_r_ok = (reference_h > -1 && reference_h < GRHR);
+    FX_BOOL line3_r_ok = (reference_h > -2 && reference_h < GRHR - 1);
+    line1_r = line1_r_ok ? pLineR[nOffset - nStrideR] : 0;
+    line2_r = line2_r_ok ? pLineR[nOffset] : 0;
+    line3_r = line3_r_ok ? pLineR[nOffset + nStrideR] : 0;
+    if (LTP == 0) {
+      CONTEXT = (line1 & 0x0380) | ((line1_r >> 2) & 0x0020) |
+                ((line2_r >> 4) & 0x001c) | ((line3_r >> 6) & 0x0003);
+      for (int32_t w = 0; w < GRW; w += 8) {
+        nBits = GRW - w > 8 ? 8 : GRW - w;
+        if (h > 0)
+          line1 = (line1 << 8) |
+                  (w + 8 < GRW ? pLine[-nStride + (w >> 3) + 1] << 1 : 0);
+        if (line1_r_ok)
+          line1_r =
+              (line1_r << 8) |
+              (w + 8 < GRWR ? pLineR[nOffset - nStrideR + (w >> 3) + 1] : 0);
+        if (line2_r_ok)
+          line2_r = (line2_r << 8) |
+                    (w + 8 < GRWR ? pLineR[nOffset + (w >> 3) + 1] : 0);
+        if (line3_r_ok) {
+          line3_r =
+              (line3_r << 8) |
+              (w + 8 < GRWR ? pLineR[nOffset + nStrideR + (w >> 3) + 1] : 0);
+        } else {
+          line3_r = 0;
+        }
+        cVal = 0;
+        for (k = 0; k < nBits; k++) {
+          bVal = pArithDecoder->DECODE(&grContext[CONTEXT]);
+          cVal |= bVal << (7 - k);
+          CONTEXT = ((CONTEXT & 0x018d) << 1) | (bVal << 6) |
+                    ((line1 >> (7 - k)) & 0x0080) |
+                    ((line1_r >> (9 - k)) & 0x0020) |
+                    ((line2_r >> (11 - k)) & 0x0004) |
+                    ((line3_r >> (13 - k)) & 0x0001);
+        }
+        pLine[w >> 3] = cVal;
+      }
+    } else {
+      CONTEXT = (line1 & 0x0380) | ((line1_r >> 2) & 0x0020) |
+                ((line2_r >> 4) & 0x001c) | ((line3_r >> 6) & 0x0003);
+      for (int32_t w = 0; w < GRW; w += 8) {
+        nBits = GRW - w > 8 ? 8 : GRW - w;
+        if (h > 0)
+          line1 = (line1 << 8) |
+                  (w + 8 < GRW ? pLine[-nStride + (w >> 3) + 1] << 1 : 0);
+        if (line1_r_ok)
+          line1_r =
+              (line1_r << 8) |
+              (w + 8 < GRWR ? pLineR[nOffset - nStrideR + (w >> 3) + 1] : 0);
+        if (line2_r_ok)
+          line2_r = (line2_r << 8) |
+                    (w + 8 < GRWR ? pLineR[nOffset + (w >> 3) + 1] : 0);
+        if (line3_r_ok) {
+          line3_r =
+              (line3_r << 8) |
+              (w + 8 < GRWR ? pLineR[nOffset + nStrideR + (w >> 3) + 1] : 0);
+        } else {
+          line3_r = 0;
+        }
+        cVal = 0;
+        for (k = 0; k < nBits; k++) {
+          bVal = GRREFERENCE->getPixel(w + k, h);
+          if (!(TPGRON && (bVal == GRREFERENCE->getPixel(w + k - 1, h - 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k, h - 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k + 1, h - 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k - 1, h)) &&
+                (bVal == GRREFERENCE->getPixel(w + k + 1, h)) &&
+                (bVal == GRREFERENCE->getPixel(w + k - 1, h + 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k, h + 1)) &&
+                (bVal == GRREFERENCE->getPixel(w + k + 1, h + 1)))) {
+            bVal = pArithDecoder->DECODE(&grContext[CONTEXT]);
+          }
+          cVal |= bVal << (7 - k);
+          CONTEXT = ((CONTEXT & 0x018d) << 1) | (bVal << 6) |
+                    ((line1 >> (7 - k)) & 0x0080) |
+                    ((line1_r >> (9 - k)) & 0x0020) |
+                    ((line2_r >> (11 - k)) & 0x0004) |
+                    ((line3_r >> (13 - k)) & 0x0001);
+        }
+        pLine[w >> 3] = cVal;
+      }
+    }
+    pLine += nStride;
+    if (h < GRHR + GRREFERENCEDY) {
+      pLineR += nStrideR;
+    }
+  }
+  return GRREG.release();
+}
-- 
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