/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * XCrush (RDP6.1) Bulk Data Compression

 *

 * Copyright 2014 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 * Copyright 2017 Armin Novak <armin.novak@thincast.com>

 * Copyright 2017 Thincast Technologies GmbH

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <winpr/assert.h>

#include <freerdp/config.h>

#include <winpr/crt.h>

#include <winpr/print.h>

#include <winpr/bitstream.h>

#include <freerdp/log.h>

#include "xcrush.h"

#define TAG FREERDP_TAG("codec")

#pragma pack(push, 1)

typedef struct

{

  UINT32 MatchOffset;

  UINT32 ChunkOffset;

  UINT32 MatchLength;

} XCRUSH_MATCH_INFO;

typedef struct

{

  UINT32 offset;

  UINT32 next;

} XCRUSH_CHUNK;

typedef struct

{

  UINT16 seed;

  UINT16 size;

} XCRUSH_SIGNATURE;

typedef struct

{

  UINT16 MatchLength;

  UINT16 MatchOutputOffset;

  UINT32 MatchHistoryOffset;

} RDP61_MATCH_DETAILS;

typedef struct

{

  BYTE Level1ComprFlags;

  BYTE Level2ComprFlags;

  UINT16 MatchCount;

  RDP61_MATCH_DETAILS* MatchDetails;

  BYTE* Literals;

} RDP61_COMPRESSED_DATA;

#pragma pack(pop)

struct s_XCRUSH_CONTEXT

{

  ALIGN64 BOOL Compressor;

  ALIGN64 MPPC_CONTEXT* mppc;

  ALIGN64 BYTE* HistoryPtr;

  ALIGN64 UINT32 HistoryOffset;

  ALIGN64 UINT32 HistoryBufferSize;

  ALIGN64 BYTE HistoryBuffer[2000000];

  ALIGN64 BYTE BlockBuffer[16384];

  ALIGN64 UINT32 CompressionFlags;

  ALIGN64 UINT32 SignatureIndex;

  ALIGN64 UINT32 SignatureCount;

  ALIGN64 XCRUSH_SIGNATURE Signatures[1000];

  ALIGN64 UINT32 ChunkHead;

  ALIGN64 UINT32 ChunkTail;

  ALIGN64 XCRUSH_CHUNK Chunks[65534];

  ALIGN64 UINT16 NextChunks[65536];

  ALIGN64 UINT32 OriginalMatchCount;

  ALIGN64 UINT32 OptimizedMatchCount;

  ALIGN64 XCRUSH_MATCH_INFO OriginalMatches[1000];

  ALIGN64 XCRUSH_MATCH_INFO OptimizedMatches[1000];

};

//#define DEBUG_XCRUSH 1

#if defined(DEBUG_XCRUSH)

static const char* xcrush_get_level_2_compression_flags_string(UINT32 flags)

{

  flags &= 0xE0;

  if (flags == 0)

    return "PACKET_UNCOMPRESSED";

  else if (flags == PACKET_COMPRESSED)

    return "PACKET_COMPRESSED";

  else if (flags == PACKET_AT_FRONT)

    return "PACKET_AT_FRONT";

  else if (flags == PACKET_FLUSHED)

    return "PACKET_FLUSHED";

  else if (flags == (PACKET_COMPRESSED | PACKET_AT_FRONT))

    return "PACKET_COMPRESSED | PACKET_AT_FRONT";

  else if (flags == (PACKET_COMPRESSED | PACKET_FLUSHED))

    return "PACKET_COMPRESSED | PACKET_FLUSHED";

  else if (flags == (PACKET_AT_FRONT | PACKET_FLUSHED))

    return "PACKET_AT_FRONT | PACKET_FLUSHED";

  else if (flags == (PACKET_COMPRESSED | PACKET_AT_FRONT | PACKET_FLUSHED))

    return "PACKET_COMPRESSED | PACKET_AT_FRONT | PACKET_FLUSHED";

  return "PACKET_UNKNOWN";

}

static const char* xcrush_get_level_1_compression_flags_string(UINT32 flags)

{

  flags &= 0x17;

  if (flags == 0)

    return "L1_UNKNOWN";

  else if (flags == L1_PACKET_AT_FRONT)

    return "L1_PACKET_AT_FRONT";

  else if (flags == L1_NO_COMPRESSION)

    return "L1_NO_COMPRESSION";

  else if (flags == L1_COMPRESSED)

    return "L1_COMPRESSED";

  else if (flags == L1_INNER_COMPRESSION)

    return "L1_INNER_COMPRESSION";

  else if (flags == (L1_PACKET_AT_FRONT | L1_NO_COMPRESSION))

    return "L1_PACKET_AT_FRONT | L1_NO_COMPRESSION";

  else if (flags == (L1_PACKET_AT_FRONT | L1_COMPRESSED))

    return "L1_PACKET_AT_FRONT | L1_COMPRESSED";

  else if (flags == (L1_PACKET_AT_FRONT | L1_INNER_COMPRESSION))

    return "L1_PACKET_AT_FRONT | L1_INNER_COMPRESSION";

  else if (flags == (L1_NO_COMPRESSION | L1_COMPRESSED))

    return "L1_NO_COMPRESSION | L1_COMPRESSED";

  else if (flags == (L1_NO_COMPRESSION | L1_INNER_COMPRESSION))

    return "L1_NO_COMPRESSION | L1_INNER_COMPRESSION";

  else if (flags == (L1_COMPRESSED | L1_INNER_COMPRESSION))

    return "L1_COMPRESSED | L1_INNER_COMPRESSION";

  else if (flags == (L1_NO_COMPRESSION | L1_COMPRESSED | L1_INNER_COMPRESSION))

    return "L1_NO_COMPRESSION | L1_COMPRESSED | L1_INNER_COMPRESSION";

  else if (flags == (L1_PACKET_AT_FRONT | L1_COMPRESSED | L1_INNER_COMPRESSION))

    return "L1_PACKET_AT_FRONT | L1_COMPRESSED | L1_INNER_COMPRESSION";

  else if (flags == (L1_PACKET_AT_FRONT | L1_NO_COMPRESSION | L1_INNER_COMPRESSION))

    return "L1_PACKET_AT_FRONT | L1_NO_COMPRESSION | L1_INNER_COMPRESSION";

  else if (flags == (L1_PACKET_AT_FRONT | L1_NO_COMPRESSION | L1_COMPRESSED))

    return "L1_PACKET_AT_FRONT | L1_NO_COMPRESSION | L1_COMPRESSED";

  else if (flags ==

           (L1_PACKET_AT_FRONT | L1_NO_COMPRESSION | L1_COMPRESSED | L1_INNER_COMPRESSION))

    return "L1_PACKET_AT_FRONT | L1_NO_COMPRESSION | L1_COMPRESSED | L1_INNER_COMPRESSION";

  return "L1_UNKNOWN";

}

#endif

static UINT32 xcrush_update_hash(const BYTE* data, UINT32 size)

{

  const BYTE* end;

  UINT32 seed = 5381; /* same value as in djb2 */

  WINPR_ASSERT(data);

  WINPR_ASSERT(size >= 4);

  if (size > 32)

  {

    size = 32;

    seed = 5413;

  }

  end = &data[size - 4];

  while (data < end)

  {

    seed += (data[3] ^ data[0]) + (data[1] << 8);

    data += 4;

  }

  return (UINT16)seed;

}

static int xcrush_append_chunk(XCRUSH_CONTEXT* xcrush, const BYTE* data, UINT32* beg, UINT32 end)

{

  UINT32 size;

  WINPR_ASSERT(xcrush);

  WINPR_ASSERT(data);

  WINPR_ASSERT(beg);

  if (xcrush->SignatureIndex >= xcrush->SignatureCount)

    return 0;

  size = end - *beg;

  if (size > 65535)

    return 0;

  if (size >= 15)

  {

    UINT32 seed = xcrush_update_hash(&data[*beg], (UINT16)size);

    xcrush->Signatures[xcrush->SignatureIndex].size = size;

    xcrush->Signatures[xcrush->SignatureIndex].seed = seed;

    xcrush->SignatureIndex++;

    *beg = end;

  }

  return 1;

}

static int xcrush_compute_chunks(XCRUSH_CONTEXT* xcrush, const BYTE* data, UINT32 size,

                                 UINT32* pIndex)

{

  UINT32 i = 0;

  UINT32 offset = 0;

  UINT32 rotation = 0;

  UINT32 accumulator = 0;

  WINPR_ASSERT(xcrush);

  WINPR_ASSERT(data);

  WINPR_ASSERT(pIndex);

  *pIndex = 0;

  xcrush->SignatureIndex = 0;

  if (size < 128)

    return 0;

  for (i = 0; i < 32; i++)

  {

    rotation = _rotl(accumulator, 1);

    accumulator = data[i] ^ rotation;

  }

  for (i = 0; i < size - 64; i++)

  {

    rotation = _rotl(accumulator, 1);

    accumulator = data[i + 32] ^ data[i] ^ rotation;

    if (!(accumulator & 0x7F))

    {

      if (!xcrush_append_chunk(xcrush, data, &offset, i + 32))

        return 0;

    }

    i++;

    rotation = _rotl(accumulator, 1);

    accumulator = data[i + 32] ^ data[i] ^ rotation;

    if (!(accumulator & 0x7F))

    {

      if (!xcrush_append_chunk(xcrush, data, &offset, i + 32))

        return 0;

    }

    i++;

    rotation = _rotl(accumulator, 1);

    accumulator = data[i + 32] ^ data[i] ^ rotation;

    if (!(accumulator & 0x7F))

    {

      if (!xcrush_append_chunk(xcrush, data, &offset, i + 32))

        return 0;

    }

    i++;

    rotation = _rotl(accumulator, 1);

    accumulator = data[i + 32] ^ data[i] ^ rotation;

    if (!(accumulator & 0x7F))

    {

      if (!xcrush_append_chunk(xcrush, data, &offset, i + 32))

        return 0;

    }

  }

  if ((size == offset) || xcrush_append_chunk(xcrush, data, &offset, size))

  {

    *pIndex = xcrush->SignatureIndex;

    return 1;

  }

  return 0;

}

static UINT32 xcrush_compute_signatures(XCRUSH_CONTEXT* xcrush, const BYTE* data, UINT32 size)

{

  UINT32 index = 0;

  if (xcrush_compute_chunks(xcrush, data, size, &index))

    return index;

  return 0;

}

static void xcrush_clear_hash_table_range(XCRUSH_CONTEXT* xcrush, UINT32 beg, UINT32 end)

{

  UINT32 index;

  WINPR_ASSERT(xcrush);

  for (index = 0; index < 65536; index++)

  {

    if (xcrush->NextChunks[index] >= beg)

    {

      if (xcrush->NextChunks[index] <= end)

      {

        xcrush->NextChunks[index] = 0;

      }

    }

  }

  for (index = 0; index < 65534; index++)

  {

    if (xcrush->Chunks[index].next >= beg)

    {

      if (xcrush->Chunks[index].next <= end)

      {

        xcrush->Chunks[index].next = 0;

      }

    }

  }

}

static int xcrush_find_next_matching_chunk(XCRUSH_CONTEXT* xcrush, XCRUSH_CHUNK* chunk,

                                           XCRUSH_CHUNK** pNextChunk)

{

  UINT32 index;

  XCRUSH_CHUNK* next = NULL;

  WINPR_ASSERT(xcrush);

  if (!chunk)

    return -4001; /* error */

  if (chunk->next)

  {

    index = (chunk - xcrush->Chunks) / sizeof(XCRUSH_CHUNK);

    if (index >= 65534)

      return -4002; /* error */

    if ((index < xcrush->ChunkHead) || (chunk->next >= xcrush->ChunkHead))

    {

      if (chunk->next >= 65534)

        return -4003; /* error */

      next = &xcrush->Chunks[chunk->next];

    }

  }

  WINPR_ASSERT(pNextChunk);

  *pNextChunk = next;

  return 1;

}

static int xcrush_insert_chunk(XCRUSH_CONTEXT* xcrush, XCRUSH_SIGNATURE* signature, UINT32 offset,

                               XCRUSH_CHUNK** pPrevChunk)

{

  UINT32 seed;

  UINT32 index;

  WINPR_ASSERT(xcrush);

  if (xcrush->ChunkHead >= 65530)

  {

    xcrush->ChunkHead = 1;

    xcrush->ChunkTail = 1;

  }

  if (xcrush->ChunkHead >= xcrush->ChunkTail)

  {

    xcrush_clear_hash_table_range(xcrush, xcrush->ChunkTail, xcrush->ChunkTail + 10000);

    xcrush->ChunkTail += 10000;

  }

  index = xcrush->ChunkHead++;

  if (xcrush->ChunkHead >= 65534)

    return -3001; /* error */

  xcrush->Chunks[index].offset = offset;

  seed = signature->seed;

  if (seed >= 65536)

    return -3002; /* error */

  if (xcrush->NextChunks[seed])

  {

    if (xcrush->NextChunks[seed] >= 65534)

      return -3003; /* error */

    WINPR_ASSERT(pPrevChunk);

    *pPrevChunk = &xcrush->Chunks[xcrush->NextChunks[seed]];

  }

  xcrush->Chunks[index].next = xcrush->NextChunks[seed] & 0xFFFF;

  xcrush->NextChunks[seed] = index;

  return 1;

}

static int xcrush_find_match_length(XCRUSH_CONTEXT* xcrush, UINT32 MatchOffset, UINT32 ChunkOffset,

                                    UINT32 HistoryOffset, UINT32 SrcSize, UINT32 MaxMatchLength,

                                    XCRUSH_MATCH_INFO* MatchInfo)

{

  UINT32 MatchSymbol;

  UINT32 ChunkSymbol;

  BYTE* ChunkBuffer;

  BYTE* MatchBuffer;

  BYTE* MatchStartPtr;

  BYTE* ForwardChunkPtr;

  BYTE* ReverseChunkPtr;

  BYTE* ForwardMatchPtr;

  BYTE* ReverseMatchPtr;

  BYTE* HistoryBufferEnd;

  UINT32 ReverseMatchLength = 0;

  UINT32 ForwardMatchLength = 0;

  UINT32 TotalMatchLength;

  BYTE* HistoryBuffer;

  UINT32 HistoryBufferSize;

  WINPR_ASSERT(xcrush);

  WINPR_ASSERT(MatchInfo);

  HistoryBuffer = xcrush->HistoryBuffer;

  HistoryBufferSize = xcrush->HistoryBufferSize;

  HistoryBufferEnd = &HistoryBuffer[HistoryOffset + SrcSize];

  if (MatchOffset > HistoryBufferSize)

    return -2001; /* error */

  MatchBuffer = &HistoryBuffer[MatchOffset];

  if (ChunkOffset > HistoryBufferSize)

    return -2002; /* error */

  ChunkBuffer = &HistoryBuffer[ChunkOffset];

  if (MatchOffset == ChunkOffset)

    return -2003; /* error */

  if (MatchBuffer < HistoryBuffer)

    return -2004; /* error */

  if (ChunkBuffer < HistoryBuffer)

    return -2005; /* error */

  ForwardMatchPtr = &HistoryBuffer[MatchOffset];

  ForwardChunkPtr = &HistoryBuffer[ChunkOffset];

  if ((&MatchBuffer[MaxMatchLength + 1] < HistoryBufferEnd) &&

      (MatchBuffer[MaxMatchLength + 1] != ChunkBuffer[MaxMatchLength + 1]))

  {

    return 0;

  }

  while (1)

  {

    MatchSymbol = *ForwardMatchPtr++;

    ChunkSymbol = *ForwardChunkPtr++;

    if (MatchSymbol != ChunkSymbol)

      break;

    if (ForwardMatchPtr > HistoryBufferEnd)

      break;

    ForwardMatchLength++;

  }

  ReverseMatchPtr = MatchBuffer - 1;

  ReverseChunkPtr = ChunkBuffer - 1;

  while ((ReverseMatchPtr > &HistoryBuffer[HistoryOffset]) && (ReverseChunkPtr > HistoryBuffer) &&

         (*ReverseMatchPtr == *ReverseChunkPtr))

  {

    ReverseMatchLength++;

    ReverseMatchPtr--;

    ReverseChunkPtr--;

  }

  MatchStartPtr = MatchBuffer - ReverseMatchLength;

  TotalMatchLength = ReverseMatchLength + ForwardMatchLength;

  if (TotalMatchLength < 11)

    return 0;

  if (MatchStartPtr < HistoryBuffer)

    return -2006; /* error */

  MatchInfo->MatchOffset = MatchStartPtr - HistoryBuffer;

  MatchInfo->ChunkOffset = ChunkBuffer - ReverseMatchLength - HistoryBuffer;

  MatchInfo->MatchLength = TotalMatchLength;

  return (int)TotalMatchLength;

}

static int xcrush_find_all_matches(XCRUSH_CONTEXT* xcrush, UINT32 SignatureIndex,

                                   UINT32 HistoryOffset, UINT32 SrcOffset, UINT32 SrcSize)

{

  UINT32 i = 0;

  UINT32 j = 0;

  int status = 0;

  UINT32 ChunkIndex = 0;

  UINT32 ChunkCount = 0;

  XCRUSH_CHUNK* chunk = NULL;

  UINT32 MatchLength = 0;

  UINT32 MaxMatchLength = 0;

  UINT32 PrevMatchEnd = 0;

  XCRUSH_SIGNATURE* Signatures = NULL;

  XCRUSH_MATCH_INFO MaxMatchInfo = { 0 };

  WINPR_ASSERT(xcrush);

  Signatures = xcrush->Signatures;

  for (i = 0; i < SignatureIndex; i++)

  {

    XCRUSH_MATCH_INFO MatchInfo = { 0 };

    UINT32 offset = SrcOffset + HistoryOffset;

    if (!Signatures[i].size)

      return -1001; /* error */

    status = xcrush_insert_chunk(xcrush, &Signatures[i], offset, &chunk);

    if (status < 0)

      return status;

    if (chunk && (SrcOffset + HistoryOffset + Signatures[i].size >= PrevMatchEnd))

    {

      ChunkCount = 0;

      MaxMatchLength = 0;

      while (chunk)

      {

        if ((chunk->offset < HistoryOffset) || (chunk->offset < offset) ||

            (chunk->offset > SrcSize + HistoryOffset))

        {

          status = xcrush_find_match_length(xcrush, offset, chunk->offset, HistoryOffset,

                                            SrcSize, MaxMatchLength, &MatchInfo);

          if (status < 0)

            return status; /* error */

          MatchLength = (UINT32)status;

          if (MatchLength > MaxMatchLength)

          {

            MaxMatchLength = MatchLength;

            MaxMatchInfo.MatchOffset = MatchInfo.MatchOffset;

            MaxMatchInfo.ChunkOffset = MatchInfo.ChunkOffset;

            MaxMatchInfo.MatchLength = MatchInfo.MatchLength;

            if (MatchLength > 256)

              break;

          }

        }

        ChunkIndex = ChunkCount++;

        if (ChunkIndex > 4)

          break;

        status = xcrush_find_next_matching_chunk(xcrush, chunk, &chunk);

        if (status < 0)

          return status; /* error */

      }

      if (MaxMatchLength)

      {

        xcrush->OriginalMatches[j].MatchOffset = MaxMatchInfo.MatchOffset;

        xcrush->OriginalMatches[j].ChunkOffset = MaxMatchInfo.ChunkOffset;

        xcrush->OriginalMatches[j].MatchLength = MaxMatchInfo.MatchLength;

        if (xcrush->OriginalMatches[j].MatchOffset < HistoryOffset)

          return -1002; /* error */

        PrevMatchEnd =

            xcrush->OriginalMatches[j].MatchLength + xcrush->OriginalMatches[j].MatchOffset;

        j++;

        if (j >= 1000)

          return -1003; /* error */

      }

    }

    SrcOffset += Signatures[i].size;

    if (SrcOffset > SrcSize)

      return -1004; /* error */

  }

  if (SrcOffset > SrcSize)

    return -1005; /* error */

  return (int)j;

}

static int xcrush_optimize_matches(XCRUSH_CONTEXT* xcrush)

{

  UINT32 i, j = 0;

  UINT32 MatchDiff = 0;

  UINT32 PrevMatchEnd = 0;

  UINT32 TotalMatchLength = 0;

  UINT32 OriginalMatchCount = 0;

  UINT32 OptimizedMatchCount = 0;

  XCRUSH_MATCH_INFO* OriginalMatch;

  XCRUSH_MATCH_INFO* OptimizedMatch;

  XCRUSH_MATCH_INFO* OriginalMatches;

  XCRUSH_MATCH_INFO* OptimizedMatches;

  WINPR_ASSERT(xcrush);

  OriginalMatches = xcrush->OriginalMatches;

  OriginalMatchCount = xcrush->OriginalMatchCount;

  OptimizedMatches = xcrush->OptimizedMatches;

  for (i = 0; i < OriginalMatchCount; i++)

  {

    if (OriginalMatches[i].MatchOffset <= PrevMatchEnd)

    {

      if ((OriginalMatches[i].MatchOffset < PrevMatchEnd) &&

          (OriginalMatches[i].MatchLength + OriginalMatches[i].MatchOffset >

           PrevMatchEnd + 6))

      {

        MatchDiff = PrevMatchEnd - OriginalMatches[i].MatchOffset;

        OriginalMatch = &OriginalMatches[i];

        OptimizedMatch = &OptimizedMatches[j];

        OptimizedMatch->MatchOffset = OriginalMatch->MatchOffset;

        OptimizedMatch->ChunkOffset = OriginalMatch->ChunkOffset;

        OptimizedMatch->MatchLength = OriginalMatch->MatchLength;

        if (OptimizedMatches[j].MatchLength <= MatchDiff)

          return -5001; /* error */

        if (MatchDiff >= 20000)

          return -5002; /* error */

        OptimizedMatches[j].MatchLength -= MatchDiff;

        OptimizedMatches[j].MatchOffset += MatchDiff;

        OptimizedMatches[j].ChunkOffset += MatchDiff;

        PrevMatchEnd = OptimizedMatches[j].MatchLength + OptimizedMatches[j].MatchOffset;

        TotalMatchLength += OptimizedMatches[j].MatchLength;

        j++;

      }

    }

    else

    {

      OriginalMatch = &OriginalMatches[i];

      OptimizedMatch = &OptimizedMatches[j];

      OptimizedMatch->MatchOffset = OriginalMatch->MatchOffset;

      OptimizedMatch->ChunkOffset = OriginalMatch->ChunkOffset;

      OptimizedMatch->MatchLength = OriginalMatch->MatchLength;

      PrevMatchEnd = OptimizedMatches[j].MatchLength + OptimizedMatches[j].MatchOffset;

      TotalMatchLength += OptimizedMatches[j].MatchLength;

      j++;

    }

  }

  OptimizedMatchCount = j;

  xcrush->OptimizedMatchCount = OptimizedMatchCount;

  return (int)TotalMatchLength;

}

static int xcrush_generate_output(XCRUSH_CONTEXT* xcrush, BYTE* OutputBuffer, UINT32 OutputSize,

                                  UINT32 HistoryOffset, UINT32* pDstSize)

{

  BYTE* Literals;

  BYTE* OutputEnd;

  UINT32 MatchIndex;

  UINT32 MatchOffset;

  UINT16 MatchLength;

  UINT32 MatchCount;

  UINT32 CurrentOffset;

  UINT32 MatchOffsetDiff;

  UINT32 HistoryOffsetDiff;

  RDP61_MATCH_DETAILS* MatchDetails;

  WINPR_ASSERT(xcrush);

  WINPR_ASSERT(OutputBuffer);

  WINPR_ASSERT(OutputSize >= 2);

  WINPR_ASSERT(pDstSize);

  MatchCount = xcrush->OptimizedMatchCount;

  OutputEnd = &OutputBuffer[OutputSize];

  if (&OutputBuffer[2] >= &OutputBuffer[OutputSize])

    return -6001; /* error */

  Data_Write_UINT16(OutputBuffer, MatchCount);

  MatchDetails = (RDP61_MATCH_DETAILS*)&OutputBuffer[2];

  Literals = (BYTE*)&MatchDetails[MatchCount];

  if (Literals > OutputEnd)

    return -6002; /* error */

  for (MatchIndex = 0; MatchIndex < MatchCount; MatchIndex++)

  {

    Data_Write_UINT16(&MatchDetails[MatchIndex].MatchLength,

                      xcrush->OptimizedMatches[MatchIndex].MatchLength);

    Data_Write_UINT16(&MatchDetails[MatchIndex].MatchOutputOffset,

                      xcrush->OptimizedMatches[MatchIndex].MatchOffset - HistoryOffset);

    Data_Write_UINT32(&MatchDetails[MatchIndex].MatchHistoryOffset,

                      xcrush->OptimizedMatches[MatchIndex].ChunkOffset);

  }

  CurrentOffset = HistoryOffset;

  for (MatchIndex = 0; MatchIndex < MatchCount; MatchIndex++)

  {

    MatchLength = (UINT16)(xcrush->OptimizedMatches[MatchIndex].MatchLength);

    MatchOffset = xcrush->OptimizedMatches[MatchIndex].MatchOffset;

    if (MatchOffset <= CurrentOffset)

    {

      if (MatchOffset != CurrentOffset)

        return -6003; /* error */

      CurrentOffset = MatchOffset + MatchLength;

    }

    else

    {

      MatchOffsetDiff = MatchOffset - CurrentOffset;

      if (Literals + MatchOffset - CurrentOffset >= OutputEnd)

        return -6004; /* error */

      CopyMemory(Literals, &xcrush->HistoryBuffer[CurrentOffset], MatchOffsetDiff);

      if (Literals >= OutputEnd)

        return -6005; /* error */

      Literals += MatchOffsetDiff;

      CurrentOffset = MatchOffset + MatchLength;

    }

  }

  HistoryOffsetDiff = xcrush->HistoryOffset - CurrentOffset;

  if (Literals + HistoryOffsetDiff >= OutputEnd)

    return -6006; /* error */

  CopyMemory(Literals, &xcrush->HistoryBuffer[CurrentOffset], HistoryOffsetDiff);

  *pDstSize = Literals + HistoryOffsetDiff - OutputBuffer;

  return 1;

}

static INLINE size_t xcrush_copy_bytes(BYTE* dst, const BYTE* src, size_t num)

{

  WINPR_ASSERT(dst);

  WINPR_ASSERT(src);

  if (src + num < dst || src > dst + num)

    memcpy(dst, src, num);

  else if (src != dst)

  {

    // src and dst overlaps

    // we should copy the area that doesn't overlap repeatly

    const size_t diff = (dst > src) ? dst - src : src - dst;

    const size_t rest = num % diff;

    const size_t end = num - rest;

    for (size_t a = 0; a < end; a += diff)

      memcpy(&dst[a], &src[a], diff);

    if (rest != 0)

      memcpy(&dst[end], &src[end], rest);

  }

  return num;

}

static int xcrush_decompress_l1(XCRUSH_CONTEXT* xcrush, const BYTE* pSrcData, UINT32 SrcSize,

                                const BYTE** ppDstData, UINT32* pDstSize, UINT32 flags)

{

  const BYTE* pSrcEnd = NULL;

  const BYTE* Literals = NULL;

  UINT16 MatchCount = 0;

  UINT16 MatchIndex = 0;

  BYTE* OutputPtr = NULL;

  size_t OutputLength = 0;

  UINT32 OutputOffset = 0;

  BYTE* HistoryPtr = NULL;

  BYTE* HistoryBuffer = NULL;

  BYTE* HistoryBufferEnd = NULL;

  UINT32 HistoryBufferSize = 0;

  UINT16 MatchLength = 0;

  UINT16 MatchOutputOffset = 0;

  UINT32 MatchHistoryOffset = 0;

  const RDP61_MATCH_DETAILS* MatchDetails = NULL;

  WINPR_ASSERT(xcrush);

  if (SrcSize < 1)

    return -1001;

  WINPR_ASSERT(pSrcData);

  WINPR_ASSERT(ppDstData);

  WINPR_ASSERT(pDstSize);

  if (flags & L1_PACKET_AT_FRONT)

    xcrush->HistoryOffset = 0;

  pSrcEnd = &pSrcData[SrcSize];

  HistoryBuffer = xcrush->HistoryBuffer;

  HistoryBufferSize = xcrush->HistoryBufferSize;

  HistoryBufferEnd = &(HistoryBuffer[HistoryBufferSize]);

  xcrush->HistoryPtr = HistoryPtr = &(HistoryBuffer[xcrush->HistoryOffset]);

  if (flags & L1_NO_COMPRESSION)

  {

    Literals = pSrcData;

  }

  else

  {

    if (!(flags & L1_COMPRESSED))

      return -1002;

    if ((pSrcData + 2) > pSrcEnd)

      return -1003;

    Data_Read_UINT16(pSrcData, MatchCount);

    MatchDetails = (const RDP61_MATCH_DETAILS*)&pSrcData[2];

    Literals = (const BYTE*)&MatchDetails[MatchCount];

    OutputOffset = 0;

    if (Literals > pSrcEnd)

      return -1004;

    for (MatchIndex = 0; MatchIndex < MatchCount; MatchIndex++)

    {

      Data_Read_UINT16(&MatchDetails[MatchIndex].MatchLength, MatchLength);

      Data_Read_UINT16(&MatchDetails[MatchIndex].MatchOutputOffset, MatchOutputOffset);

      Data_Read_UINT32(&MatchDetails[MatchIndex].MatchHistoryOffset, MatchHistoryOffset);

      if (MatchOutputOffset < OutputOffset)

        return -1005;

      if (MatchLength > HistoryBufferSize)

        return -1006;

      if (MatchHistoryOffset > HistoryBufferSize)

        return -1007;

      OutputLength = MatchOutputOffset - OutputOffset;

      if ((MatchOutputOffset - OutputOffset) > HistoryBufferSize)

        return -1008;

      if (OutputLength > 0)

      {

        if ((&HistoryPtr[OutputLength] >= HistoryBufferEnd) || (Literals >= pSrcEnd) ||

            (&Literals[OutputLength] > pSrcEnd))

          return -1009;

        xcrush_copy_bytes(HistoryPtr, Literals, OutputLength);

        HistoryPtr += OutputLength;

        Literals += OutputLength;

        OutputOffset += OutputLength;

        if (Literals > pSrcEnd)

          return -1010;

      }

      OutputPtr = &xcrush->HistoryBuffer[MatchHistoryOffset];

      if ((&HistoryPtr[MatchLength] >= HistoryBufferEnd) ||

          (&OutputPtr[MatchLength] >= HistoryBufferEnd))

        return -1011;

      xcrush_copy_bytes(HistoryPtr, OutputPtr, MatchLength);

      OutputOffset += MatchLength;

      HistoryPtr += MatchLength;

    }

  }

  if (Literals < pSrcEnd)

  {

    OutputLength = pSrcEnd - Literals;

    if ((&HistoryPtr[OutputLength] >= HistoryBufferEnd) || (&Literals[OutputLength] > pSrcEnd))

      return -1012;

    xcrush_copy_bytes(HistoryPtr, Literals, OutputLength);

    HistoryPtr += OutputLength;

  }

  xcrush->HistoryOffset = HistoryPtr - HistoryBuffer;

  *pDstSize = HistoryPtr - xcrush->HistoryPtr;

  *ppDstData = xcrush->HistoryPtr;

  return 1;