/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS system libraries
* PURPOSE: Compression and decompression functions
* FILE: lib/rtl/compress.c
* PROGRAMER: Eric Kohl
Sebastian Lackner
Michael Müller
*/
/* INCLUDES *****************************************************************/
#include <rtl.h>
#define NDEBUG
#include <debug.h>
/* MACROS *******************************************************************/
#define COMPRESSION_FORMAT_MASK 0x00FF
#define COMPRESSION_ENGINE_MASK 0xFF00
/* FUNCTIONS ****************************************************************/
/* Based on Wine Staging */
/* decompress a single LZNT1 chunk */
static PUCHAR lznt1_decompress_chunk(UCHAR *dst, ULONG dst_size, UCHAR *src, ULONG src_size)
{
UCHAR *src_cur, *src_end, *dst_cur, *dst_end;
ULONG displacement_bits, length_bits;
ULONG code_displacement, code_length;
WORD flags, code;
src_cur = src;
src_end = src + src_size;
dst_cur = dst;
dst_end = dst + dst_size;
/* Partial decompression is no error on Windows. */
while (src_cur < src_end && dst_cur < dst_end)
{
/* read flags header */
flags = 0x8000 | *src_cur++;
/* parse following 8 entities, either uncompressed data or backwards reference */
while ((flags & 0xFF00) && src_cur < src_end)
{
if (flags & 1)
{
/* backwards reference */
if (src_cur + sizeof(WORD) > src_end)
return NULL;
code = *(WORD *)src_cur;
src_cur += sizeof(WORD);
/* find length / displacement bits */
for (displacement_bits = 12; displacement_bits > 4; displacement_bits--)
if ((1 << (displacement_bits - 1)) < dst_cur - dst) break;
length_bits = 16 - displacement_bits;
code_length = (code & ((1 << length_bits) - 1)) + 3;
code_displacement = (code >> length_bits) + 1;
/* ensure reference is valid */
if (dst_cur < dst + code_displacement)
return NULL;
/* copy bytes of chunk - we can't use memcpy()
* since source and dest can be overlapping */
while (code_length--)
{
if (dst_cur >= dst_end) return dst_cur;
*dst_cur = *(dst_cur - code_displacement);
dst_cur++;
}
}
else
{
/* uncompressed data */
if (dst_cur >= dst_end) return dst_cur;
*dst_cur++ = *src_cur++;
}
flags >>= 1;
}
}
return dst_cur;
}
/* decompress data encoded with LZNT1 */
static NTSTATUS lznt1_decompress(UCHAR *dst, ULONG dst_size, UCHAR *src, ULONG src_size,
ULONG offset, ULONG *final_size, UCHAR *workspace)
{
UCHAR *src_cur = src, *src_end = src + src_size;
UCHAR *dst_cur = dst, *dst_end = dst + dst_size;
ULONG chunk_size, block_size;
WORD chunk_header;
UCHAR *ptr;
if (src_cur + sizeof(WORD) > src_end)
return STATUS_BAD_COMPRESSION_BUFFER;
/* skip over chunks which have a big distance (>= 0x1000) to the destination offset */
while (offset >= 0x1000 && src_cur + sizeof(WORD) <= src_end)
{
/* read chunk header and extract size */
chunk_header = *(WORD *)src_cur;
src_cur += sizeof(WORD);
if (!chunk_header) goto out;
chunk_size = (chunk_header & 0xFFF) + 1;
/* ensure we have enough buffer to process chunk */
if (src_cur + chunk_size > src_end)
return STATUS_BAD_COMPRESSION_BUFFER;
src_cur += chunk_size;
offset -= 0x1000;
}
/* this chunk is can be included partially */
if (offset && src_cur + sizeof(WORD) <= src_end)
{
/* read chunk header and extract size */
chunk_header = *(WORD *)src_cur;
src_cur += sizeof(WORD);
if (!chunk_header) goto out;
chunk_size = (chunk_header & 0xFFF) + 1;
/* ensure we have enough buffer to process chunk */
if (src_cur + chunk_size > src_end)
return STATUS_BAD_COMPRESSION_BUFFER;
if (dst_cur >= dst_end)
goto out;
if (chunk_header & 0x8000)
{
/* compressed chunk */
if (!workspace) return STATUS_ACCESS_VIOLATION;
ptr = lznt1_decompress_chunk(workspace, 0x1000, src_cur, chunk_size);
if (!ptr) return STATUS_BAD_COMPRESSION_BUFFER;
if (ptr - workspace > offset)
{
block_size = min((ptr - workspace) - offset, dst_end - dst_cur);
memcpy(dst_cur, workspace + offset, block_size);
dst_cur += block_size;
}
}
else
{
/* uncompressed chunk */
if (chunk_size > offset)
{
block_size = min(chunk_size - offset, dst_end - dst_cur);
memcpy(dst_cur, src_cur + offset, block_size);
dst_cur += block_size;
}
}
src_cur += chunk_size;
}
/* handle remaining chunks */
while (src_cur + sizeof(WORD) <= src_end)
{
/* read chunk header and extract size */
chunk_header = *(WORD *)src_cur;
src_cur += sizeof(WORD);
if (!chunk_header) goto out;
chunk_size = (chunk_header & 0xFFF) + 1;
if (src_cur + chunk_size > src_end)
return STATUS_BAD_COMPRESSION_BUFFER;
/* add padding if required */
block_size = ((dst_cur - dst) + offset) & 0xFFF;
if (block_size)
{
block_size = 0x1000 - block_size;
if (dst_cur + block_size >= dst_end)
goto out;
memset(dst_cur, 0, block_size);
dst_cur += block_size;
}
if (dst_cur >= dst_end)
goto out;
if (chunk_header & 0x8000)
{
/* compressed chunk */
dst_cur = lznt1_decompress_chunk(dst_cur, dst_end - dst_cur, src_cur, chunk_size);
if (!dst_cur) return STATUS_BAD_COMPRESSION_BUFFER;
}
else
{
/* uncompressed chunk */
block_size = min(chunk_size, dst_end - dst_cur);
memcpy(dst_cur, src_cur, block_size);
dst_cur += block_size;
}
src_cur += chunk_size;
}
out:
if (final_size)
*final_size = dst_cur - dst;
return STATUS_SUCCESS;
}
static NTSTATUS
RtlpCompressBufferLZNT1(UCHAR *src, ULONG src_size, UCHAR *dst, ULONG dst_size,
ULONG chunk_size, ULONG *final_size, UCHAR *workspace)
{
UCHAR *src_cur = src, *src_end = src + src_size;
UCHAR *dst_cur = dst, *dst_end = dst + dst_size;
ULONG block_size;
while (src_cur < src_end)
{
/* determine size of current chunk */
block_size = min(0x1000, src_end - src_cur);
if (dst_cur + sizeof(WORD) + block_size > dst_end)
return STATUS_BUFFER_TOO_SMALL;
/* write (uncompressed) chunk header */
*(WORD *)dst_cur = 0x3000 | (block_size - 1);
dst_cur += sizeof(WORD);
/* write chunk content */
memcpy(dst_cur, src_cur, block_size);
dst_cur += block_size;
src_cur += block_size;
}
if (final_size)
*final_size = dst_cur - dst;
return STATUS_SUCCESS;
}
static NTSTATUS
RtlpWorkSpaceSizeLZNT1(USHORT Engine,
PULONG BufferAndWorkSpaceSize,
PULONG FragmentWorkSpaceSize)
{
if (Engine == COMPRESSION_ENGINE_STANDARD)
{
*BufferAndWorkSpaceSize = 0x8010;
*FragmentWorkSpaceSize = 0x1000;
return(STATUS_SUCCESS);
}
else if (Engine == COMPRESSION_ENGINE_MAXIMUM)
{
*BufferAndWorkSpaceSize = 0x10;
*FragmentWorkSpaceSize = 0x1000;
return(STATUS_SUCCESS);
}
return(STATUS_NOT_SUPPORTED);
}
/*
* @implemented
*/
NTSTATUS NTAPI
RtlCompressBuffer(IN USHORT CompressionFormatAndEngine,
IN PUCHAR UncompressedBuffer,
IN ULONG UncompressedBufferSize,
OUT PUCHAR CompressedBuffer,
IN ULONG CompressedBufferSize,
IN ULONG UncompressedChunkSize,
OUT PULONG FinalCompressedSize,
IN PVOID WorkSpace)
{
USHORT Format = CompressionFormatAndEngine & COMPRESSION_FORMAT_MASK;
/* USHORT Engine = CompressionFormatAndEngine & COMPRESSION_ENGINE_MASK; */
if ((Format == COMPRESSION_FORMAT_NONE) ||
(Format == COMPRESSION_FORMAT_DEFAULT))
return(STATUS_INVALID_PARAMETER);
if (Format == COMPRESSION_FORMAT_LZNT1)
return(RtlpCompressBufferLZNT1(UncompressedBuffer,
UncompressedBufferSize,
CompressedBuffer,
CompressedBufferSize,
UncompressedChunkSize,
FinalCompressedSize,
WorkSpace));
return(STATUS_UNSUPPORTED_COMPRESSION);
}
/*
* @unimplemented
*/
NTSTATUS NTAPI
RtlCompressChunks(IN PUCHAR UncompressedBuffer,
IN ULONG UncompressedBufferSize,
OUT PUCHAR CompressedBuffer,
IN ULONG CompressedBufferSize,
IN OUT PCOMPRESSED_DATA_INFO CompressedDataInfo,
IN ULONG CompressedDataInfoLength,
IN PVOID WorkSpace)
{
UNIMPLEMENTED;
return STATUS_NOT_IMPLEMENTED;
}
/*
* @unimplemented
*/
NTSTATUS NTAPI
RtlDecompressChunks(OUT PUCHAR UncompressedBuffer,
IN ULONG UncompressedBufferSize,
IN PUCHAR CompressedBuffer,
IN ULONG CompressedBufferSize,
IN PUCHAR CompressedTail,
IN ULONG CompressedTailSize,
IN PCOMPRESSED_DATA_INFO CompressedDataInfo)
{
UNIMPLEMENTED;
return STATUS_NOT_IMPLEMENTED;
}
/*
* @implemented
*/
NTSTATUS NTAPI
RtlDecompressFragment(IN USHORT format,
OUT PUCHAR uncompressed,
IN ULONG uncompressed_size,
IN PUCHAR compressed,
IN ULONG compressed_size,
IN ULONG offset,
OUT PULONG final_size,
IN PVOID workspace)
{
DPRINT("0x%04x, %p, %u, %p, %u, %u, %p, %p :stub\n", format, uncompressed,
uncompressed_size, compressed, compressed_size, offset, final_size, workspace);
switch (format & ~COMPRESSION_ENGINE_MAXIMUM)
{
case COMPRESSION_FORMAT_LZNT1:
return lznt1_decompress(uncompressed, uncompressed_size, compressed,
compressed_size, offset, final_size, workspace);
case COMPRESSION_FORMAT_NONE:
case COMPRESSION_FORMAT_DEFAULT:
return STATUS_INVALID_PARAMETER;
default:
DPRINT1("format %d not implemented\n", format);
return STATUS_UNSUPPORTED_COMPRESSION;
}
}
/*
* @implemented
*/
NTSTATUS NTAPI
RtlDecompressBuffer(IN USHORT CompressionFormat,
OUT PUCHAR UncompressedBuffer,
IN ULONG UncompressedBufferSize,
IN PUCHAR CompressedBuffer,
IN ULONG CompressedBufferSize,
OUT PULONG FinalUncompressedSize)
{
return RtlDecompressFragment(CompressionFormat, UncompressedBuffer, UncompressedBufferSize,
CompressedBuffer, CompressedBufferSize, 0, FinalUncompressedSize, NULL);
}
/*
* @unimplemented
*/
NTSTATUS NTAPI
RtlDescribeChunk(IN USHORT CompressionFormat,
IN OUT PUCHAR *CompressedBuffer,
IN PUCHAR EndOfCompressedBufferPlus1,
OUT PUCHAR *ChunkBuffer,
OUT PULONG ChunkSize)
{
UNIMPLEMENTED;
return STATUS_NOT_IMPLEMENTED;
}
/*
* @unimplemented
*/
NTSTATUS NTAPI
RtlGetCompressionWorkSpaceSize(IN USHORT CompressionFormatAndEngine,
OUT PULONG CompressBufferAndWorkSpaceSize,
OUT PULONG CompressFragmentWorkSpaceSize)
{
USHORT Format = CompressionFormatAndEngine & COMPRESSION_FORMAT_MASK;
USHORT Engine = CompressionFormatAndEngine & COMPRESSION_ENGINE_MASK;
if ((Format == COMPRESSION_FORMAT_NONE) ||
(Format == COMPRESSION_FORMAT_DEFAULT))
return(STATUS_INVALID_PARAMETER);
if (Format == COMPRESSION_FORMAT_LZNT1)
return(RtlpWorkSpaceSizeLZNT1(Engine,
CompressBufferAndWorkSpaceSize,
CompressFragmentWorkSpaceSize));
return(STATUS_UNSUPPORTED_COMPRESSION);
}
/*
* @unimplemented
*/
NTSTATUS NTAPI
RtlReserveChunk(IN USHORT CompressionFormat,
IN OUT PUCHAR *CompressedBuffer,
IN PUCHAR EndOfCompressedBufferPlus1,
OUT PUCHAR *ChunkBuffer,
IN ULONG ChunkSize)
{
UNIMPLEMENTED;
return STATUS_NOT_IMPLEMENTED;
}
/* EOF */