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authorlgao4 <lgao4@6f19259b-4bc3-4df7-8a09-765794883524>2012-03-19 07:13:29 +0000
committerlgao4 <lgao4@6f19259b-4bc3-4df7-8a09-765794883524>2012-03-19 07:13:29 +0000
commit5aab2d509403352d97809649eaad26f7f44e170c (patch)
tree5af358c8ed2eb171a648ab0070ace9229b6e8c09
parent16d2c32c4dff7fd8b0ee19e3ba908c0121f6636e (diff)
downloadedk2-5aab2d509403352d97809649eaad26f7f44e170c.zip
edk2-5aab2d509403352d97809649eaad26f7f44e170c.tar.gz
edk2-5aab2d509403352d97809649eaad26f7f44e170c.tar.bz2
Add LzmaArchCustomDecompressLib library instance, which supports for X86 (IA32/X64) optimized decompression. It can provide the improved compression for IA32 and X64 architecture code.
Signed-off-by: lgao4 Reviewed-by: jljusten git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13111 6f19259b-4bc3-4df7-8a09-765794883524
-rw-r--r--IntelFrameworkModulePkg/Include/Guid/LzmaDecompress.h10
-rw-r--r--IntelFrameworkModulePkg/IntelFrameworkModulePkg.dec3
-rw-r--r--IntelFrameworkModulePkg/IntelFrameworkModulePkg.dsc3
-rw-r--r--IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/F86GuidedSectionExtraction.c218
-rw-r--r--IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/LzmaArchCustomDecompressLib.inf66
-rw-r--r--IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/Bra.h60
-rw-r--r--IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/Bra86.c85
7 files changed, 442 insertions, 3 deletions
diff --git a/IntelFrameworkModulePkg/Include/Guid/LzmaDecompress.h b/IntelFrameworkModulePkg/Include/Guid/LzmaDecompress.h
index 6d5af93..18a6552 100644
--- a/IntelFrameworkModulePkg/Include/Guid/LzmaDecompress.h
+++ b/IntelFrameworkModulePkg/Include/Guid/LzmaDecompress.h
@@ -1,7 +1,7 @@
/** @file
Lzma Custom decompress algorithm Guid definition.
-Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2009 - 2012, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials are licensed and made available under
the terms and conditions of the BSD License that accompanies this distribution.
The full text of the license may be found at
@@ -22,6 +22,14 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#define LZMA_CUSTOM_DECOMPRESS_GUID \
{ 0xEE4E5898, 0x3914, 0x4259, { 0x9D, 0x6E, 0xDC, 0x7B, 0xD7, 0x94, 0x03, 0xCF } }
+///
+/// The Global ID used to identify a section of an FFS file of type
+/// EFI_SECTION_GUID_DEFINED, whose contents have been compressed using LZMA with X86 code Converter.
+///
+#define LZMAF86_CUSTOM_DECOMPRESS_GUID \
+ { 0xD42AE6BD, 0x1352, 0x4bfb, { 0x90, 0x9A, 0xCA, 0x72, 0xA6, 0xEA, 0xE8, 0x89 } }
+
extern GUID gLzmaCustomDecompressGuid;
+extern GUID gLzmaF86CustomDecompressGuid;
#endif
diff --git a/IntelFrameworkModulePkg/IntelFrameworkModulePkg.dec b/IntelFrameworkModulePkg/IntelFrameworkModulePkg.dec
index 0c46885..cb39877 100644
--- a/IntelFrameworkModulePkg/IntelFrameworkModulePkg.dec
+++ b/IntelFrameworkModulePkg/IntelFrameworkModulePkg.dec
@@ -2,7 +2,7 @@
# Intel Framework Module Package contains the definitions and module implementation
# which follows Intel EFI Framework Specification.
#
-# Copyright (c) 2007 - 2011, Intel Corporation. All rights reserved.<BR>
+# Copyright (c) 2007 - 2012, Intel Corporation. All rights reserved.<BR>
#
# This program and the accompanying materials
# are licensed and made available under the terms and conditions of the BSD License
@@ -46,6 +46,7 @@
## GUID indicates the LZMA custom compress/decompress algorithm.
# Include/Guid/LzmaDecompress.h
gLzmaCustomDecompressGuid = { 0xEE4E5898, 0x3914, 0x4259, { 0x9D, 0x6E, 0xDC, 0x7B, 0xD7, 0x94, 0x03, 0xCF }}
+ gLzmaF86CustomDecompressGuid = { 0xD42AE6BD, 0x1352, 0x4bfb, { 0x90, 0x9A, 0xCA, 0x72, 0xA6, 0xEA, 0xE8, 0x89 }}
## Include/Guid/AcpiVariable.h
gEfiAcpiVariableCompatiblityGuid = { 0xc020489e, 0x6db2, 0x4ef2, { 0x9a, 0xa5, 0xca, 0x6, 0xfc, 0x11, 0xd3, 0x6a }}
diff --git a/IntelFrameworkModulePkg/IntelFrameworkModulePkg.dsc b/IntelFrameworkModulePkg/IntelFrameworkModulePkg.dsc
index 70a8a39..b004067 100644
--- a/IntelFrameworkModulePkg/IntelFrameworkModulePkg.dsc
+++ b/IntelFrameworkModulePkg/IntelFrameworkModulePkg.dsc
@@ -3,7 +3,7 @@
#
# This file is used to build all modules in IntelFrameworkModulePkg.
#
-#Copyright (c) 2007 - 2011, Intel Corporation. All rights reserved.<BR>
+#Copyright (c) 2007 - 2012, Intel Corporation. All rights reserved.<BR>
#This program and the accompanying materials are licensed and made available under
#the terms and conditions of the BSD License that accompanies this distribution.
#The full text of the license may be found at
@@ -167,6 +167,7 @@
[Components.IA32,Components.X64]
IntelFrameworkModulePkg/Universal/Acpi/AcpiS3SaveDxe/AcpiS3SaveDxe.inf
+ IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/LzmaArchCustomDecompressLib.inf
[Components.IA32,Components.X64,Components.IPF]
IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosDxe.inf
diff --git a/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/F86GuidedSectionExtraction.c b/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/F86GuidedSectionExtraction.c
new file mode 100644
index 0000000..4f870a1
--- /dev/null
+++ b/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/F86GuidedSectionExtraction.c
@@ -0,0 +1,218 @@
+/** @file
+ LZMA Decompress GUIDed Section Extraction Library, which produces LZMA custom
+ decompression algorithm with the converter for the different arch code.
+ It wraps Lzma decompress interfaces to GUIDed Section Extraction interfaces
+ and registers them into GUIDed handler table.
+
+ Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
+ This program and the accompanying materials
+ are licensed and made available under the terms and conditions of the BSD License
+ which accompanies this distribution. The full text of the license may be found at
+ http://opensource.org/licenses/bsd-license.php
+
+ THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "LzmaDecompressLibInternal.h"
+#include "Sdk/C/Bra.h"
+
+/**
+ Examines a GUIDed section and returns the size of the decoded buffer and the
+ size of an scratch buffer required to actually decode the data in a GUIDed section.
+
+ Examines a GUIDed section specified by InputSection.
+ If GUID for InputSection does not match the GUID that this handler supports,
+ then RETURN_UNSUPPORTED is returned.
+ If the required information can not be retrieved from InputSection,
+ then RETURN_INVALID_PARAMETER is returned.
+ If the GUID of InputSection does match the GUID that this handler supports,
+ then the size required to hold the decoded buffer is returned in OututBufferSize,
+ the size of an optional scratch buffer is returned in ScratchSize, and the Attributes field
+ from EFI_GUID_DEFINED_SECTION header of InputSection is returned in SectionAttribute.
+
+ If InputSection is NULL, then ASSERT().
+ If OutputBufferSize is NULL, then ASSERT().
+ If ScratchBufferSize is NULL, then ASSERT().
+ If SectionAttribute is NULL, then ASSERT().
+
+
+ @param[in] InputSection A pointer to a GUIDed section of an FFS formatted file.
+ @param[out] OutputBufferSize A pointer to the size, in bytes, of an output buffer required
+ if the buffer specified by InputSection were decoded.
+ @param[out] ScratchBufferSize A pointer to the size, in bytes, required as scratch space
+ if the buffer specified by InputSection were decoded.
+ @param[out] SectionAttribute A pointer to the attributes of the GUIDed section. See the Attributes
+ field of EFI_GUID_DEFINED_SECTION in the PI Specification.
+
+ @retval RETURN_SUCCESS The information about InputSection was returned.
+ @retval RETURN_UNSUPPORTED The section specified by InputSection does not match the GUID this handler supports.
+ @retval RETURN_INVALID_PARAMETER The information can not be retrieved from the section specified by InputSection.
+
+**/
+RETURN_STATUS
+EFIAPI
+LzmaArchGuidedSectionGetInfo (
+ IN CONST VOID *InputSection,
+ OUT UINT32 *OutputBufferSize,
+ OUT UINT32 *ScratchBufferSize,
+ OUT UINT16 *SectionAttribute
+ )
+{
+ ASSERT (InputSection != NULL);
+ ASSERT (OutputBufferSize != NULL);
+ ASSERT (ScratchBufferSize != NULL);
+ ASSERT (SectionAttribute != NULL);
+
+ if (IS_SECTION2 (InputSection)) {
+ if (!CompareGuid (
+ &gLzmaF86CustomDecompressGuid,
+ &(((EFI_GUID_DEFINED_SECTION2 *) InputSection)->SectionDefinitionGuid))) {
+ return RETURN_INVALID_PARAMETER;
+ }
+
+ *SectionAttribute = ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->Attributes;
+
+ return LzmaUefiDecompressGetInfo (
+ (UINT8 *) InputSection + ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->DataOffset,
+ SECTION2_SIZE (InputSection) - ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->DataOffset,
+ OutputBufferSize,
+ ScratchBufferSize
+ );
+ } else {
+ if (!CompareGuid (
+ &gLzmaF86CustomDecompressGuid,
+ &(((EFI_GUID_DEFINED_SECTION *) InputSection)->SectionDefinitionGuid))) {
+ return RETURN_INVALID_PARAMETER;
+ }
+
+ *SectionAttribute = ((EFI_GUID_DEFINED_SECTION *) InputSection)->Attributes;
+
+ return LzmaUefiDecompressGetInfo (
+ (UINT8 *) InputSection + ((EFI_GUID_DEFINED_SECTION *) InputSection)->DataOffset,
+ SECTION_SIZE (InputSection) - ((EFI_GUID_DEFINED_SECTION *) InputSection)->DataOffset,
+ OutputBufferSize,
+ ScratchBufferSize
+ );
+ }
+}
+
+/**
+ Decompress a LZAM compressed GUIDed section into a caller allocated output buffer.
+
+ Decodes the GUIDed section specified by InputSection.
+ If GUID for InputSection does not match the GUID that this handler supports, then RETURN_UNSUPPORTED is returned.
+ If the data in InputSection can not be decoded, then RETURN_INVALID_PARAMETER is returned.
+ If the GUID of InputSection does match the GUID that this handler supports, then InputSection
+ is decoded into the buffer specified by OutputBuffer and the authentication status of this
+ decode operation is returned in AuthenticationStatus. If the decoded buffer is identical to the
+ data in InputSection, then OutputBuffer is set to point at the data in InputSection. Otherwise,
+ the decoded data will be placed in caller allocated buffer specified by OutputBuffer.
+
+ If InputSection is NULL, then ASSERT().
+ If OutputBuffer is NULL, then ASSERT().
+ If ScratchBuffer is NULL and this decode operation requires a scratch buffer, then ASSERT().
+ If AuthenticationStatus is NULL, then ASSERT().
+
+
+ @param[in] InputSection A pointer to a GUIDed section of an FFS formatted file.
+ @param[out] OutputBuffer A pointer to a buffer that contains the result of a decode operation.
+ @param[out] ScratchBuffer A caller allocated buffer that may be required by this function
+ as a scratch buffer to perform the decode operation.
+ @param[out] AuthenticationStatus
+ A pointer to the authentication status of the decoded output buffer.
+ See the definition of authentication status in the EFI_PEI_GUIDED_SECTION_EXTRACTION_PPI
+ section of the PI Specification. EFI_AUTH_STATUS_PLATFORM_OVERRIDE must
+ never be set by this handler.
+
+ @retval RETURN_SUCCESS The buffer specified by InputSection was decoded.
+ @retval RETURN_UNSUPPORTED The section specified by InputSection does not match the GUID this handler supports.
+ @retval RETURN_INVALID_PARAMETER The section specified by InputSection can not be decoded.
+
+**/
+RETURN_STATUS
+EFIAPI
+LzmaArchGuidedSectionExtraction (
+ IN CONST VOID *InputSection,
+ OUT VOID **OutputBuffer,
+ OUT VOID *ScratchBuffer, OPTIONAL
+ OUT UINT32 *AuthenticationStatus
+ )
+{
+ EFI_GUID *InputGuid;
+ VOID *Source;
+ UINTN SourceSize;
+ EFI_STATUS Status;
+ UINT32 X86State;
+ UINT32 OutputBufferSize;
+ UINT32 ScratchBufferSize;
+
+ ASSERT (OutputBuffer != NULL);
+ ASSERT (InputSection != NULL);
+
+ if (IS_SECTION2 (InputSection)) {
+ InputGuid = &(((EFI_GUID_DEFINED_SECTION2 *) InputSection)->SectionDefinitionGuid);
+ Source = (UINT8 *) InputSection + ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->DataOffset;
+ SourceSize = SECTION2_SIZE (InputSection) - ((EFI_GUID_DEFINED_SECTION2 *) InputSection)->DataOffset;
+ } else {
+ InputGuid = &(((EFI_GUID_DEFINED_SECTION *) InputSection)->SectionDefinitionGuid);
+ Source = (UINT8 *) InputSection + ((EFI_GUID_DEFINED_SECTION *) InputSection)->DataOffset;
+ SourceSize = SECTION_SIZE (InputSection) - ((EFI_GUID_DEFINED_SECTION *) InputSection)->DataOffset;
+ }
+
+ if (!CompareGuid (&gLzmaF86CustomDecompressGuid, InputGuid)) {
+ return RETURN_INVALID_PARAMETER;
+ }
+
+ //
+ // Authentication is set to Zero, which may be ignored.
+ //
+ *AuthenticationStatus = 0;
+
+ Status = LzmaUefiDecompress (
+ Source,
+ SourceSize,
+ *OutputBuffer,
+ ScratchBuffer
+ );
+
+ //
+ // After decompress, the data need to be converted to the raw data.
+ //
+ if (!EFI_ERROR (Status)) {
+ Status = LzmaUefiDecompressGetInfo (
+ Source,
+ SourceSize,
+ &OutputBufferSize,
+ &ScratchBufferSize
+ );
+
+ if (!EFI_ERROR (Status)) {
+ x86_Convert_Init(X86State);
+ x86_Convert(*OutputBuffer, OutputBufferSize, 0, &X86State, 0);
+ }
+ }
+
+ return Status;
+}
+
+
+/**
+ Register LzmaArchDecompress and LzmaArchDecompressGetInfo handlers with LzmaF86CustomDecompressGuid.
+
+ @retval RETURN_SUCCESS Register successfully.
+ @retval RETURN_OUT_OF_RESOURCES No enough memory to store this handler.
+**/
+EFI_STATUS
+EFIAPI
+LzmaArchDecompressLibConstructor (
+ )
+{
+ return ExtractGuidedSectionRegisterHandlers (
+ &gLzmaF86CustomDecompressGuid,
+ LzmaArchGuidedSectionGetInfo,
+ LzmaArchGuidedSectionExtraction
+ );
+}
+
diff --git a/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/LzmaArchCustomDecompressLib.inf b/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/LzmaArchCustomDecompressLib.inf
new file mode 100644
index 0000000..9dda211
--- /dev/null
+++ b/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/LzmaArchCustomDecompressLib.inf
@@ -0,0 +1,66 @@
+## @file
+# LzmaArchCustomDecompressLib produces LZMA custom decompression algorithm
+# with the converter for the different arch code.
+#
+# It is based on the LZMA SDK 4.65.
+# LZMA SDK 4.65 was placed in the public domain on 2009-02-03.
+# It was released on the http://www.7-zip.org/sdk.html website.
+#
+# Copyright (c) 2012, Intel Corporation. All rights reserved.<BR>
+#
+# This program and the accompanying materials
+# are licensed and made available under the terms and conditions of the BSD License
+# which accompanies this distribution. The full text of the license may be found at
+# http://opensource.org/licenses/bsd-license.php
+# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#
+#
+##
+
+[Defines]
+ INF_VERSION = 0x00010005
+ BASE_NAME = LzmaArchDecompressLib
+ FILE_GUID = A853C1D2-E003-4cc4-9DD1-8824AD79FE48
+ MODULE_TYPE = BASE
+ VERSION_STRING = 1.0
+ LIBRARY_CLASS = NULL
+ CONSTRUCTOR = LzmaArchDecompressLibConstructor
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+# VALID_ARCHITECTURES = IA32 X64
+#
+
+[Sources]
+ LzmaDecompress.c
+ Sdk/C/Bra.h
+ Sdk/C/LzFind.c
+ Sdk/C/LzmaDec.c
+ Sdk/C/7zVersion.h
+ Sdk/C/CpuArch.h
+ Sdk/C/LzFind.h
+ Sdk/C/LzHash.h
+ Sdk/C/LzmaDec.h
+ Sdk/C/Types.h
+ UefiLzma.h
+ LzmaDecompressLibInternal.h
+
+[Sources.Ia32, Sources.X64]
+ Sdk/C/Bra86.c
+ F86GuidedSectionExtraction.c
+
+[Packages]
+ MdePkg/MdePkg.dec
+ IntelFrameworkModulePkg/IntelFrameworkModulePkg.dec
+
+[Guids.Ia32, Guids.X64]
+ gLzmaF86CustomDecompressGuid ## PRODUCED ## GUID specifies LZMA custom decompress algorithm with converter for x86 code.
+
+[LibraryClasses]
+ BaseLib
+ DebugLib
+ BaseMemoryLib
+ ExtractGuidedSectionLib
+
diff --git a/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/Bra.h b/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/Bra.h
new file mode 100644
index 0000000..b9018eb
--- /dev/null
+++ b/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/Bra.h
@@ -0,0 +1,60 @@
+/* Bra.h -- Branch converters for executables
+2008-10-04 : Igor Pavlov : Public domain */
+
+#ifndef __BRA_H
+#define __BRA_H
+
+#include "Types.h"
+
+/*
+These functions convert relative addresses to absolute addresses
+in CALL instructions to increase the compression ratio.
+
+ In:
+ data - data buffer
+ size - size of data
+ ip - current virtual Instruction Pinter (IP) value
+ state - state variable for x86 converter
+ encoding - 0 (for decoding), 1 (for encoding)
+
+ Out:
+ state - state variable for x86 converter
+
+ Returns:
+ The number of processed bytes. If you call these functions with multiple calls,
+ you must start next call with first byte after block of processed bytes.
+
+ Type Endian Alignment LookAhead
+
+ x86 little 1 4
+ ARMT little 2 2
+ ARM little 4 0
+ PPC big 4 0
+ SPARC big 4 0
+ IA64 little 16 0
+
+ size must be >= Alignment + LookAhead, if it's not last block.
+ If (size < Alignment + LookAhead), converter returns 0.
+
+ Example:
+
+ UInt32 ip = 0;
+ for ()
+ {
+ ; size must be >= Alignment + LookAhead, if it's not last block
+ SizeT processed = Convert(data, size, ip, 1);
+ data += processed;
+ size -= processed;
+ ip += processed;
+ }
+*/
+
+#define x86_Convert_Init(state) { state = 0; }
+SizeT x86_Convert(Byte *data, SizeT size, UInt32 ip, UInt32 *state, int encoding);
+SizeT ARM_Convert(Byte *data, SizeT size, UInt32 ip, int encoding);
+SizeT ARMT_Convert(Byte *data, SizeT size, UInt32 ip, int encoding);
+SizeT PPC_Convert(Byte *data, SizeT size, UInt32 ip, int encoding);
+SizeT SPARC_Convert(Byte *data, SizeT size, UInt32 ip, int encoding);
+SizeT IA64_Convert(Byte *data, SizeT size, UInt32 ip, int encoding);
+
+#endif
diff --git a/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/Bra86.c b/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/Bra86.c
new file mode 100644
index 0000000..93566cb
--- /dev/null
+++ b/IntelFrameworkModulePkg/Library/LzmaCustomDecompressLib/Sdk/C/Bra86.c
@@ -0,0 +1,85 @@
+/* Bra86.c -- Converter for x86 code (BCJ)
+2008-10-04 : Igor Pavlov : Public domain */
+
+#include "Bra.h"
+
+#define Test86MSByte(b) ((b) == 0 || (b) == 0xFF)
+
+const Byte kMaskToAllowedStatus[8] = {1, 1, 1, 0, 1, 0, 0, 0};
+const Byte kMaskToBitNumber[8] = {0, 1, 2, 2, 3, 3, 3, 3};
+
+SizeT x86_Convert(Byte *data, SizeT size, UInt32 ip, UInt32 *state, int encoding)
+{
+ SizeT bufferPos = 0, prevPosT;
+ UInt32 prevMask = *state & 0x7;
+ if (size < 5)
+ return 0;
+ ip += 5;
+ prevPosT = (SizeT)0 - 1;
+
+ for (;;)
+ {
+ Byte *p = data + bufferPos;
+ Byte *limit = data + size - 4;
+ for (; p < limit; p++)
+ if ((*p & 0xFE) == 0xE8)
+ break;
+ bufferPos = (SizeT)(p - data);
+ if (p >= limit)
+ break;
+ prevPosT = bufferPos - prevPosT;
+ if (prevPosT > 3)
+ prevMask = 0;
+ else
+ {
+ prevMask = (prevMask << ((int)prevPosT - 1)) & 0x7;
+ if (prevMask != 0)
+ {
+ Byte b = p[4 - kMaskToBitNumber[prevMask]];
+ if (!kMaskToAllowedStatus[prevMask] || Test86MSByte(b))
+ {
+ prevPosT = bufferPos;
+ prevMask = ((prevMask << 1) & 0x7) | 1;
+ bufferPos++;
+ continue;
+ }
+ }
+ }
+ prevPosT = bufferPos;
+
+ if (Test86MSByte(p[4]))
+ {
+ UInt32 src = ((UInt32)p[4] << 24) | ((UInt32)p[3] << 16) | ((UInt32)p[2] << 8) | ((UInt32)p[1]);
+ UInt32 dest;
+ for (;;)
+ {
+ Byte b;
+ int index;
+ if (encoding)
+ dest = (ip + (UInt32)bufferPos) + src;
+ else
+ dest = src - (ip + (UInt32)bufferPos);
+ if (prevMask == 0)
+ break;
+ index = kMaskToBitNumber[prevMask] * 8;
+ b = (Byte)(dest >> (24 - index));
+ if (!Test86MSByte(b))
+ break;
+ src = dest ^ ((1 << (32 - index)) - 1);
+ }
+ p[4] = (Byte)(~(((dest >> 24) & 1) - 1));
+ p[3] = (Byte)(dest >> 16);
+ p[2] = (Byte)(dest >> 8);
+ p[1] = (Byte)dest;
+ bufferPos += 5;
+ }
+ else
+ {
+ prevMask = ((prevMask << 1) & 0x7) | 1;
+ bufferPos++;
+ }
+ }
+ prevPosT = bufferPos - prevPosT;
+ *state = ((prevPosT > 3) ? 0 : ((prevMask << ((int)prevPosT - 1)) & 0x7));
+ return bufferPos;
+}