Rename remaining fx_codec*.cpp to match class and .h file name

Then include headers in the proper order per standards, since
it will no longer trigger a presubmit warning.

Change-Id: I6bb86ac90e8fd9aed30b66dac61726f0dea8222c
Reviewed-on: https://pdfium-review.googlesource.com/41535
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 852 insertions, 0 deletions

diff --git a/core/fxcodec/codec/ccodec_flatemodule.cpp b/core/fxcodec/codec/ccodec_flatemodule.cpp
new file mode 100644
index 0000000000..9074038c96
--- /dev/null
+++ b/core/fxcodec/codec/ccodec_flatemodule.cpp
@@ -0,0 +1,852 @@
+// Copyright 2014 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 "core/fxcodec/codec/ccodec_flatemodule.h"
+
+#include <algorithm>
+#include <limits>
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "core/fxcodec/codec/ccodec_scanlinedecoder.h"
+#include "core/fxcodec/fx_codec.h"
+#include "core/fxcrt/fx_extension.h"
+#include "third_party/base/numerics/safe_conversions.h"
+#include "third_party/base/ptr_util.h"
+#include "third_party/base/span.h"
+
+#if defined(USE_SYSTEM_ZLIB)
+#include <zlib.h>
+#else
+#include "third_party/zlib/zlib.h"
+#endif
+
+extern "C" {
+
+static void* my_alloc_func(void* opaque,
+                           unsigned int items,
+                           unsigned int size) {
+  return FX_Alloc2D(uint8_t, items, size);
+}
+
+static void my_free_func(void* opaque, void* address) {
+  FX_Free(address);
+}
+
+}  // extern "C"
+
+namespace {
+
+static constexpr uint32_t kMaxTotalOutSize = 1024 * 1024 * 1024;  // 1 GiB
+
+uint32_t FlateGetPossiblyTruncatedTotalOut(z_stream* context) {
+  return std::min(pdfium::base::saturated_cast<uint32_t>(context->total_out),
+                  kMaxTotalOutSize);
+}
+
+uint32_t FlateGetPossiblyTruncatedTotalIn(z_stream* context) {
+  return pdfium::base::saturated_cast<uint32_t>(context->total_in);
+}
+
+bool FlateCompress(unsigned char* dest_buf,
+                   unsigned long* dest_size,
+                   const unsigned char* src_buf,
+                   uint32_t src_size) {
+  return compress(dest_buf, dest_size, src_buf, src_size) == Z_OK;
+}
+
+z_stream* FlateInit() {
+  z_stream* p = FX_Alloc(z_stream, 1);
+  p->zalloc = my_alloc_func;
+  p->zfree = my_free_func;
+  inflateInit(p);
+  return p;
+}
+
+void FlateInput(z_stream* context, pdfium::span<const uint8_t> src_buf) {
+  context->next_in = const_cast<unsigned char*>(src_buf.data());
+  context->avail_in = static_cast<uint32_t>(src_buf.size());
+}
+
+uint32_t FlateOutput(z_stream* context,
+                     unsigned char* dest_buf,
+                     uint32_t dest_size) {
+  context->next_out = dest_buf;
+  context->avail_out = dest_size;
+  uint32_t pre_pos = FlateGetPossiblyTruncatedTotalOut(context);
+  int ret = inflate(static_cast<z_stream*>(context), Z_SYNC_FLUSH);
+
+  uint32_t post_pos = FlateGetPossiblyTruncatedTotalOut(context);
+  ASSERT(post_pos >= pre_pos);
+
+  uint32_t written = post_pos - pre_pos;
+  if (written < dest_size)
+    memset(dest_buf + written, '\0', dest_size - written);
+
+  return ret;
+}
+
+uint32_t FlateGetAvailOut(z_stream* context) {
+  return context->avail_out;
+}
+
+void FlateEnd(z_stream* context) {
+  inflateEnd(context);
+  FX_Free(context);
+}
+
+// For use with std::unique_ptr<z_stream>.
+struct FlateDeleter {
+  inline void operator()(z_stream* context) { FlateEnd(context); }
+};
+
+class CLZWDecoder {
+ public:
+  int Decode(uint8_t* output,
+             uint32_t& outlen,
+             const uint8_t* input,
+             uint32_t& size,
+             bool bEarlyChange);
+
+ private:
+  void AddCode(uint32_t prefix_code, uint8_t append_char);
+  void DecodeString(uint32_t code);
+
+  uint32_t m_InPos;
+  uint32_t m_OutPos;
+  uint8_t* m_pOutput;
+  const uint8_t* m_pInput;
+  bool m_Early;
+  uint32_t m_nCodes;
+  uint32_t m_StackLen;
+  int m_CodeLen;
+  uint32_t m_CodeArray[5021];
+  uint8_t m_DecodeStack[4000];
+};
+
+void CLZWDecoder::AddCode(uint32_t prefix_code, uint8_t append_char) {
+  if (m_nCodes + m_Early == 4094) {
+    return;
+  }
+  m_CodeArray[m_nCodes++] = (prefix_code << 16) | append_char;
+  if (m_nCodes + m_Early == 512 - 258) {
+    m_CodeLen = 10;
+  } else if (m_nCodes + m_Early == 1024 - 258) {
+    m_CodeLen = 11;
+  } else if (m_nCodes + m_Early == 2048 - 258) {
+    m_CodeLen = 12;
+  }
+}
+
+void CLZWDecoder::DecodeString(uint32_t code) {
+  while (1) {
+    int index = code - 258;
+    if (index < 0 || index >= (int)m_nCodes) {
+      break;
+    }
+    uint32_t data = m_CodeArray[index];
+    if (m_StackLen >= sizeof(m_DecodeStack)) {
+      return;
+    }
+    m_DecodeStack[m_StackLen++] = (uint8_t)data;
+    code = data >> 16;
+  }
+  if (m_StackLen >= sizeof(m_DecodeStack)) {
+    return;
+  }
+  m_DecodeStack[m_StackLen++] = (uint8_t)code;
+}
+
+int CLZWDecoder::Decode(uint8_t* dest_buf,
+                        uint32_t& dest_size,
+                        const uint8_t* src_buf,
+                        uint32_t& src_size,
+                        bool bEarlyChange) {
+  m_CodeLen = 9;
+  m_InPos = 0;
+  m_OutPos = 0;
+  m_pInput = src_buf;
+  m_pOutput = dest_buf;
+  m_Early = bEarlyChange ? 1 : 0;
+  m_nCodes = 0;
+  uint32_t old_code = 0xFFFFFFFF;
+  uint8_t last_char = 0;
+  while (1) {
+    if (m_InPos + m_CodeLen > src_size * 8) {
+      break;
+    }
+    int byte_pos = m_InPos / 8;
+    int bit_pos = m_InPos % 8, bit_left = m_CodeLen;
+    uint32_t code = 0;
+    if (bit_pos) {
+      bit_left -= 8 - bit_pos;
+      code = (m_pInput[byte_pos++] & ((1 << (8 - bit_pos)) - 1)) << bit_left;
+    }
+    if (bit_left < 8) {
+      code |= m_pInput[byte_pos] >> (8 - bit_left);
+    } else {
+      bit_left -= 8;
+      code |= m_pInput[byte_pos++] << bit_left;
+      if (bit_left) {
+        code |= m_pInput[byte_pos] >> (8 - bit_left);
+      }
+    }
+    m_InPos += m_CodeLen;
+    if (code == 257)
+      break;
+    if (code < 256) {
+      if (m_OutPos == dest_size) {
+        return -5;
+      }
+      if (m_pOutput) {
+        m_pOutput[m_OutPos] = (uint8_t)code;
+      }
+      m_OutPos++;
+      last_char = (uint8_t)code;
+      if (old_code != 0xFFFFFFFF)
+        AddCode(old_code, last_char);
+      old_code = code;
+    } else if (code == 256) {
+      m_CodeLen = 9;
+      m_nCodes = 0;
+      old_code = 0xFFFFFFFF;
+    } else {
+      // Else 257 or greater.
+      if (old_code == 0xFFFFFFFF)
+        return 2;
+
+      m_StackLen = 0;
+      if (code >= m_nCodes + 258) {
+        if (m_StackLen < sizeof(m_DecodeStack)) {
+          m_DecodeStack[m_StackLen++] = last_char;
+        }
+        DecodeString(old_code);
+      } else {
+        DecodeString(code);
+      }
+      if (m_OutPos + m_StackLen > dest_size) {
+        return -5;
+      }
+      if (m_pOutput) {
+        for (uint32_t i = 0; i < m_StackLen; i++) {
+          m_pOutput[m_OutPos + i] = m_DecodeStack[m_StackLen - i - 1];
+        }
+      }
+      m_OutPos += m_StackLen;
+      last_char = m_DecodeStack[m_StackLen - 1];
+      if (old_code < 256) {
+        AddCode(old_code, last_char);
+      } else if (old_code - 258 >= m_nCodes) {
+        dest_size = m_OutPos;
+        src_size = (m_InPos + 7) / 8;
+        return 0;
+      } else {
+        AddCode(old_code, last_char);
+      }
+      old_code = code;
+    }
+  }
+  dest_size = m_OutPos;
+  src_size = (m_InPos + 7) / 8;
+  return 0;
+}
+
+uint8_t PathPredictor(int a, int b, int c) {
+  int p = a + b - c;
+  int pa = abs(p - a);
+  int pb = abs(p - b);
+  int pc = abs(p - c);
+  if (pa <= pb && pa <= pc)
+    return (uint8_t)a;
+  if (pb <= pc)
+    return (uint8_t)b;
+  return (uint8_t)c;
+}
+
+void PNG_PredictLine(uint8_t* pDestData,
+                     const uint8_t* pSrcData,
+                     const uint8_t* pLastLine,
+                     int bpc,
+                     int nColors,
+                     int nPixels) {
+  const uint32_t row_size = CalculatePitch8(bpc, nColors, nPixels).ValueOrDie();
+  const uint32_t BytesPerPixel = (bpc * nColors + 7) / 8;
+  uint8_t tag = pSrcData[0];
+  if (tag == 0) {
+    memmove(pDestData, pSrcData + 1, row_size);
+    return;
+  }
+  for (uint32_t byte = 0; byte < row_size; ++byte) {
+    uint8_t raw_byte = pSrcData[byte + 1];
+    switch (tag) {
+      case 1: {
+        uint8_t left = 0;
+        if (byte >= BytesPerPixel) {
+          left = pDestData[byte - BytesPerPixel];
+        }
+        pDestData[byte] = raw_byte + left;
+        break;
+      }
+      case 2: {
+        uint8_t up = 0;
+        if (pLastLine) {
+          up = pLastLine[byte];
+        }
+        pDestData[byte] = raw_byte + up;
+        break;
+      }
+      case 3: {
+        uint8_t left = 0;
+        if (byte >= BytesPerPixel) {
+          left = pDestData[byte - BytesPerPixel];
+        }
+        uint8_t up = 0;
+        if (pLastLine) {
+          up = pLastLine[byte];
+        }
+        pDestData[byte] = raw_byte + (up + left) / 2;
+        break;
+      }
+      case 4: {
+        uint8_t left = 0;
+        if (byte >= BytesPerPixel) {
+          left = pDestData[byte - BytesPerPixel];
+        }
+        uint8_t up = 0;
+        if (pLastLine) {
+          up = pLastLine[byte];
+        }
+        uint8_t upper_left = 0;
+        if (byte >= BytesPerPixel && pLastLine) {
+          upper_left = pLastLine[byte - BytesPerPixel];
+        }
+        pDestData[byte] = raw_byte + PathPredictor(left, up, upper_left);
+        break;
+      }
+      default:
+        pDestData[byte] = raw_byte;
+        break;
+    }
+  }
+}
+
+bool PNG_Predictor(uint8_t*& data_buf,
+                   uint32_t& data_size,
+                   int Colors,
+                   int BitsPerComponent,
+                   int Columns) {
+  // TODO(thestig): Look into using CalculatePitch8() here.
+  const int BytesPerPixel = (Colors * BitsPerComponent + 7) / 8;
+  const int row_size = (Colors * BitsPerComponent * Columns + 7) / 8;
+  if (row_size <= 0)
+    return false;
+  const int row_count = (data_size + row_size) / (row_size + 1);
+  if (row_count <= 0)
+    return false;
+  const int last_row_size = data_size % (row_size + 1);
+  uint8_t* dest_buf = FX_Alloc2D(uint8_t, row_size, row_count);
+  uint32_t byte_cnt = 0;
+  uint8_t* pSrcData = data_buf;
+  uint8_t* pDestData = dest_buf;
+  for (int row = 0; row < row_count; row++) {
+    uint8_t tag = pSrcData[0];
+    byte_cnt++;
+    if (tag == 0) {
+      int move_size = row_size;
+      if ((row + 1) * (move_size + 1) > (int)data_size) {
+        move_size = last_row_size - 1;
+      }
+      memmove(pDestData, pSrcData + 1, move_size);
+      pSrcData += move_size + 1;
+      pDestData += move_size;
+      byte_cnt += move_size;
+      continue;
+    }
+    for (int byte = 0; byte < row_size && byte_cnt < data_size;
+         ++byte, ++byte_cnt) {
+      uint8_t raw_byte = pSrcData[byte + 1];
+      switch (tag) {
+        case 1: {
+          uint8_t left = 0;
+          if (byte >= BytesPerPixel) {
+            left = pDestData[byte - BytesPerPixel];
+          }
+          pDestData[byte] = raw_byte + left;
+          break;
+        }
+        case 2: {
+          uint8_t up = 0;
+          if (row) {
+            up = pDestData[byte - row_size];
+          }
+          pDestData[byte] = raw_byte + up;
+          break;
+        }
+        case 3: {
+          uint8_t left = 0;
+          if (byte >= BytesPerPixel) {
+            left = pDestData[byte - BytesPerPixel];
+          }
+          uint8_t up = 0;
+          if (row) {
+            up = pDestData[byte - row_size];
+          }
+          pDestData[byte] = raw_byte + (up + left) / 2;
+          break;
+        }
+        case 4: {
+          uint8_t left = 0;
+          if (byte >= BytesPerPixel) {
+            left = pDestData[byte - BytesPerPixel];
+          }
+          uint8_t up = 0;
+          if (row) {
+            up = pDestData[byte - row_size];
+          }
+          uint8_t upper_left = 0;
+          if (byte >= BytesPerPixel && row) {
+            upper_left = pDestData[byte - row_size - BytesPerPixel];
+          }
+          pDestData[byte] = raw_byte + PathPredictor(left, up, upper_left);
+          break;
+        }
+        default:
+          pDestData[byte] = raw_byte;
+          break;
+      }
+    }
+    pSrcData += row_size + 1;
+    pDestData += row_size;
+  }
+  FX_Free(data_buf);
+  data_buf = dest_buf;
+  data_size = row_size * row_count -
+              (last_row_size > 0 ? (row_size + 1 - last_row_size) : 0);
+  return true;
+}
+
+void TIFF_PredictLine(uint8_t* dest_buf,
+                      uint32_t row_size,
+                      int BitsPerComponent,
+                      int Colors,
+                      int Columns) {
+  if (BitsPerComponent == 1) {
+    int row_bits = std::min(BitsPerComponent * Colors * Columns,
+                            pdfium::base::checked_cast<int>(row_size * 8));
+    int index_pre = 0;
+    int col_pre = 0;
+    for (int i = 1; i < row_bits; i++) {
+      int col = i % 8;
+      int index = i / 8;
+      if (((dest_buf[index] >> (7 - col)) & 1) ^
+          ((dest_buf[index_pre] >> (7 - col_pre)) & 1)) {
+        dest_buf[index] |= 1 << (7 - col);
+      } else {
+        dest_buf[index] &= ~(1 << (7 - col));
+      }
+      index_pre = index;
+      col_pre = col;
+    }
+    return;
+  }
+  int BytesPerPixel = BitsPerComponent * Colors / 8;
+  if (BitsPerComponent == 16) {
+    for (uint32_t i = BytesPerPixel; i + 1 < row_size; i += 2) {
+      uint16_t pixel =
+          (dest_buf[i - BytesPerPixel] << 8) | dest_buf[i - BytesPerPixel + 1];
+      pixel += (dest_buf[i] << 8) | dest_buf[i + 1];
+      dest_buf[i] = pixel >> 8;
+      dest_buf[i + 1] = (uint8_t)pixel;
+    }
+  } else {
+    for (uint32_t i = BytesPerPixel; i < row_size; i++) {
+      dest_buf[i] += dest_buf[i - BytesPerPixel];
+    }
+  }
+}
+
+bool TIFF_Predictor(uint8_t*& data_buf,
+                    uint32_t& data_size,
+                    int Colors,
+                    int BitsPerComponent,
+                    int Columns) {
+  int row_size = (Colors * BitsPerComponent * Columns + 7) / 8;
+  if (row_size == 0)
+    return false;
+  const int row_count = (data_size + row_size - 1) / row_size;
+  const int last_row_size = data_size % row_size;
+  for (int row = 0; row < row_count; row++) {
+    uint8_t* scan_line = data_buf + row * row_size;
+    if ((row + 1) * row_size > (int)data_size) {
+      row_size = last_row_size;
+    }
+    TIFF_PredictLine(scan_line, row_size, BitsPerComponent, Colors, Columns);
+  }
+  return true;
+}
+
+void FlateUncompress(pdfium::span<const uint8_t> src_buf,
+                     uint32_t orig_size,
+                     uint8_t*& dest_buf,
+                     uint32_t& dest_size,
+                     uint32_t& offset) {
+  dest_buf = nullptr;
+  dest_size = 0;
+
+  std::unique_ptr<z_stream, FlateDeleter> context(FlateInit());
+  if (!context)
+    return;
+
+  FlateInput(context.get(), src_buf);
+
+  const uint32_t kMaxInitialAllocSize = 10000000;
+  uint32_t guess_size = orig_size ? orig_size : src_buf.size() * 2;
+  guess_size = std::min(guess_size, kMaxInitialAllocSize);
+
+  uint32_t buf_size = guess_size;
+  uint32_t last_buf_size = buf_size;
+  std::unique_ptr<uint8_t, FxFreeDeleter> guess_buf(
+      FX_Alloc(uint8_t, guess_size + 1));
+  guess_buf.get()[guess_size] = '\0';
+
+  std::vector<uint8_t*> result_tmp_bufs;
+  uint8_t* cur_buf = guess_buf.release();
+  while (1) {
+    uint32_t ret = FlateOutput(context.get(), cur_buf, buf_size);
+    uint32_t avail_buf_size = FlateGetAvailOut(context.get());
+    if (ret != Z_OK || avail_buf_size != 0) {
+      last_buf_size = buf_size - avail_buf_size;
+      result_tmp_bufs.push_back(cur_buf);
+      break;
+    }
+    result_tmp_bufs.push_back(cur_buf);
+    cur_buf = FX_Alloc(uint8_t, buf_size + 1);
+    cur_buf[buf_size] = '\0';
+  }
+
+  // The TotalOut size returned from the library may not be big enough to
+  // handle the content the library returns. We can only handle items
+  // up to 4GB in size.
+  dest_size = FlateGetPossiblyTruncatedTotalOut(context.get());
+  offset = FlateGetPossiblyTruncatedTotalIn(context.get());
+  if (result_tmp_bufs.size() == 1) {
+    dest_buf = result_tmp_bufs[0];
+    return;
+  }
+
+  uint8_t* result_buf = FX_Alloc(uint8_t, dest_size);
+  uint32_t result_pos = 0;
+  uint32_t remaining = dest_size;
+  for (size_t i = 0; i < result_tmp_bufs.size(); i++) {
+    uint8_t* tmp_buf = result_tmp_bufs[i];
+    uint32_t tmp_buf_size = buf_size;
+    if (i == result_tmp_bufs.size() - 1)
+      tmp_buf_size = last_buf_size;
+
+    uint32_t cp_size = std::min(tmp_buf_size, remaining);
+    memcpy(result_buf + result_pos, tmp_buf, cp_size);
+    result_pos += cp_size;
+    remaining -= cp_size;
+
+    FX_Free(result_tmp_bufs[i]);
+  }
+  dest_buf = result_buf;
+}
+
+enum class PredictorType : uint8_t { kNone, kFlate, kPng };
+static PredictorType GetPredictor(int predictor) {
+  if (predictor >= 10)
+    return PredictorType::kPng;
+  if (predictor == 2)
+    return PredictorType::kFlate;
+  return PredictorType::kNone;
+}
+
+class CCodec_FlateScanlineDecoder : public CCodec_ScanlineDecoder {
+ public:
+  CCodec_FlateScanlineDecoder(const uint8_t* src_buf,
+                              uint32_t src_size,
+                              int width,
+                              int height,
+                              int nComps,
+                              int bpc);
+  ~CCodec_FlateScanlineDecoder() override;
+
+  // CCodec_ScanlineDecoder:
+  bool v_Rewind() override;
+  uint8_t* v_GetNextLine() override;
+  uint32_t GetSrcOffset() override;
+
+ protected:
+  std::unique_ptr<z_stream, FlateDeleter> m_pFlate;
+  pdfium::span<const uint8_t> const m_SrcBuf;
+  std::unique_ptr<uint8_t, FxFreeDeleter> const m_pScanline;
+};
+
+CCodec_FlateScanlineDecoder::CCodec_FlateScanlineDecoder(const uint8_t* src_buf,
+                                                         uint32_t src_size,
+                                                         int width,
+                                                         int height,
+                                                         int nComps,
+                                                         int bpc)
+    : CCodec_ScanlineDecoder(width,
+                             height,
+                             width,
+                             height,
+                             nComps,
+                             bpc,
+                             CalculatePitch8(bpc, nComps, width).ValueOrDie()),
+      m_SrcBuf(src_buf, src_size),
+      m_pScanline(FX_Alloc(uint8_t, m_Pitch)) {}
+
+CCodec_FlateScanlineDecoder::~CCodec_FlateScanlineDecoder() = default;
+
+bool CCodec_FlateScanlineDecoder::v_Rewind() {
+  m_pFlate.reset(FlateInit());
+  if (!m_pFlate)
+    return false;
+
+  FlateInput(m_pFlate.get(), m_SrcBuf);
+  return true;
+}
+
+uint8_t* CCodec_FlateScanlineDecoder::v_GetNextLine() {
+  FlateOutput(m_pFlate.get(), m_pScanline.get(), m_Pitch);
+  return m_pScanline.get();
+}
+
+uint32_t CCodec_FlateScanlineDecoder::GetSrcOffset() {
+  return FlateGetPossiblyTruncatedTotalIn(m_pFlate.get());
+}
+
+class CCodec_FlatePredictorScanlineDecoder final
+    : public CCodec_FlateScanlineDecoder {
+ public:
+  CCodec_FlatePredictorScanlineDecoder(const uint8_t* src_buf,
+                                       uint32_t src_size,
+                                       int width,
+                                       int height,
+                                       int comps,
+                                       int bpc,
+                                       PredictorType predictor,
+                                       int Colors,
+                                       int BitsPerComponent,
+                                       int Columns);
+  ~CCodec_FlatePredictorScanlineDecoder() override;
+
+  // CCodec_ScanlineDecoder:
+  bool v_Rewind() override;
+  uint8_t* v_GetNextLine() override;
+
+ protected:
+  void GetNextLineWithPredictedPitch();
+  void GetNextLineWithoutPredictedPitch();
+
+  const PredictorType m_Predictor;
+  int m_Colors = 0;
+  int m_BitsPerComponent = 0;
+  int m_Columns = 0;
+  uint32_t m_PredictPitch = 0;
+  size_t m_LeftOver = 0;
+  uint8_t* m_pLastLine = nullptr;
+  uint8_t* m_pPredictBuffer = nullptr;
+  uint8_t* m_pPredictRaw = nullptr;
+};
+
+CCodec_FlatePredictorScanlineDecoder::CCodec_FlatePredictorScanlineDecoder(
+    const uint8_t* src_buf,
+    uint32_t src_size,
+    int width,
+    int height,
+    int comps,
+    int bpc,
+    PredictorType predictor,
+    int Colors,
+    int BitsPerComponent,
+    int Columns)
+    : CCodec_FlateScanlineDecoder(src_buf, src_size, width, height, comps, bpc),
+      m_Predictor(predictor) {
+  ASSERT(m_Predictor != PredictorType::kNone);
+  if (BitsPerComponent * Colors * Columns == 0) {
+    BitsPerComponent = m_bpc;
+    Colors = m_nComps;
+    Columns = m_OrigWidth;
+  }
+  m_Colors = Colors;
+  m_BitsPerComponent = BitsPerComponent;
+  m_Columns = Columns;
+  m_PredictPitch =
+      CalculatePitch8(m_BitsPerComponent, m_Colors, m_Columns).ValueOrDie();
+  m_pLastLine = FX_Alloc(uint8_t, m_PredictPitch);
+  m_pPredictBuffer = FX_Alloc(uint8_t, m_PredictPitch);
+  m_pPredictRaw = FX_Alloc(uint8_t, m_PredictPitch + 1);
+}
+
+CCodec_FlatePredictorScanlineDecoder::~CCodec_FlatePredictorScanlineDecoder() {
+  FX_Free(m_pLastLine);
+  FX_Free(m_pPredictBuffer);
+  FX_Free(m_pPredictRaw);
+}
+
+bool CCodec_FlatePredictorScanlineDecoder::v_Rewind() {
+  if (!CCodec_FlateScanlineDecoder::v_Rewind())
+    return false;
+
+  m_LeftOver = 0;
+  return true;
+}
+
+uint8_t* CCodec_FlatePredictorScanlineDecoder::v_GetNextLine() {
+  if (m_Pitch == m_PredictPitch)
+    GetNextLineWithPredictedPitch();
+  else
+    GetNextLineWithoutPredictedPitch();
+  return m_pScanline.get();
+}
+
+void CCodec_FlatePredictorScanlineDecoder::GetNextLineWithPredictedPitch() {
+  switch (m_Predictor) {
+    case PredictorType::kPng:
+      FlateOutput(m_pFlate.get(), m_pPredictRaw, m_PredictPitch + 1);
+      PNG_PredictLine(m_pScanline.get(), m_pPredictRaw, m_pLastLine,
+                      m_BitsPerComponent, m_Colors, m_Columns);
+      memcpy(m_pLastLine, m_pScanline.get(), m_PredictPitch);
+      break;
+    case PredictorType::kFlate:
+      FlateOutput(m_pFlate.get(), m_pScanline.get(), m_Pitch);
+      TIFF_PredictLine(m_pScanline.get(), m_PredictPitch, m_bpc, m_nComps,
+                       m_OutputWidth);
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+}
+
+void CCodec_FlatePredictorScanlineDecoder::GetNextLineWithoutPredictedPitch() {
+  size_t bytes_to_go = m_Pitch;
+  size_t read_leftover = m_LeftOver > bytes_to_go ? bytes_to_go : m_LeftOver;
+  if (read_leftover) {
+    memcpy(m_pScanline.get(), m_pPredictBuffer + m_PredictPitch - m_LeftOver,
+           read_leftover);
+    m_LeftOver -= read_leftover;
+    bytes_to_go -= read_leftover;
+  }
+  while (bytes_to_go) {
+    switch (m_Predictor) {
+      case PredictorType::kPng:
+        FlateOutput(m_pFlate.get(), m_pPredictRaw, m_PredictPitch + 1);
+        PNG_PredictLine(m_pPredictBuffer, m_pPredictRaw, m_pLastLine,
+                        m_BitsPerComponent, m_Colors, m_Columns);
+        memcpy(m_pLastLine, m_pPredictBuffer, m_PredictPitch);
+        break;
+      case PredictorType::kFlate:
+        FlateOutput(m_pFlate.get(), m_pPredictBuffer, m_PredictPitch);
+        TIFF_PredictLine(m_pPredictBuffer, m_PredictPitch, m_BitsPerComponent,
+                         m_Colors, m_Columns);
+        break;
+      default:
+        NOTREACHED();
+        break;
+    }
+    size_t read_bytes =
+        m_PredictPitch > bytes_to_go ? bytes_to_go : m_PredictPitch;
+    memcpy(m_pScanline.get() + m_Pitch - bytes_to_go, m_pPredictBuffer,
+           read_bytes);
+    m_LeftOver += m_PredictPitch - read_bytes;
+    bytes_to_go -= read_bytes;
+  }
+}
+
+}  // namespace
+
+std::unique_ptr<CCodec_ScanlineDecoder> CCodec_FlateModule::CreateDecoder(
+    const uint8_t* src_buf,
+    uint32_t src_size,
+    int width,
+    int height,
+    int nComps,
+    int bpc,
+    int predictor,
+    int Colors,
+    int BitsPerComponent,
+    int Columns) {
+  PredictorType predictor_type = GetPredictor(predictor);
+  if (predictor_type == PredictorType::kNone) {
+    return pdfium::MakeUnique<CCodec_FlateScanlineDecoder>(
+        src_buf, src_size, width, height, nComps, bpc);
+  }
+  return pdfium::MakeUnique<CCodec_FlatePredictorScanlineDecoder>(
+      src_buf, src_size, width, height, nComps, bpc, predictor_type, Colors,
+      BitsPerComponent, Columns);
+}
+
+uint32_t CCodec_FlateModule::FlateOrLZWDecode(bool bLZW,
+                                              const uint8_t* src_buf,
+                                              uint32_t src_size,
+                                              bool bEarlyChange,
+                                              int predictor,
+                                              int Colors,
+                                              int BitsPerComponent,
+                                              int Columns,
+                                              uint32_t estimated_size,
+                                              uint8_t** dest_buf,
+                                              uint32_t* dest_size) {
+  *dest_buf = nullptr;
+  uint32_t offset = 0;
+  PredictorType predictor_type = GetPredictor(predictor);
+
+  if (bLZW) {
+    auto decoder = pdfium::MakeUnique<CLZWDecoder>();
+    *dest_size = 0xFFFFFFFF;
+    offset = src_size;
+    int err =
+        decoder->Decode(nullptr, *dest_size, src_buf, offset, bEarlyChange);
+    if (err || *dest_size == 0 || *dest_size + 1 < *dest_size)
+      return FX_INVALID_OFFSET;
+
+    decoder = pdfium::MakeUnique<CLZWDecoder>();
+    *dest_buf = FX_Alloc(uint8_t, *dest_size + 1);
+    (*dest_buf)[*dest_size] = '\0';
+    decoder->Decode(*dest_buf, *dest_size, src_buf, offset, bEarlyChange);
+  } else {
+    FlateUncompress(pdfium::make_span(src_buf, src_size), estimated_size,
+                    *dest_buf, *dest_size, offset);
+  }
+
+  bool ret = false;
+  switch (predictor_type) {
+    case PredictorType::kNone:
+      return offset;
+    case PredictorType::kPng:
+      ret = PNG_Predictor(*dest_buf, *dest_size, Colors, BitsPerComponent,
+                          Columns);
+      break;
+    case PredictorType::kFlate:
+      ret = TIFF_Predictor(*dest_buf, *dest_size, Colors, BitsPerComponent,
+                           Columns);
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+  return ret ? offset : FX_INVALID_OFFSET;
+}
+
+bool CCodec_FlateModule::Encode(const uint8_t* src_buf,
+                                uint32_t src_size,
+                                uint8_t** dest_buf,
+                                uint32_t* dest_size) {
+  *dest_size = src_size + src_size / 1000 + 12;
+  *dest_buf = FX_Alloc(uint8_t, *dest_size);
+  unsigned long temp_size = *dest_size;
+  if (!FlateCompress(*dest_buf, &temp_size, src_buf, src_size))
+    return false;
+
+  *dest_size = (uint32_t)temp_size;
+  return true;
+}