source-engine/tier1/lzmaDecoder.cpp
2022-06-05 01:14:23 +03:00

406 lines
12 KiB
C++

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// LZMA Codec interface for engine.
//
// LZMA SDK 9.38 beta
// 2015-01-03 : Igor Pavlov : Public domain
// http://www.7-zip.org/
//
//========================================================================//
#define _LZMADECODER_CPP
#include "tier0/platform.h"
#include "tier0/basetypes.h"
#include "tier0/dbg.h"
#include "../utils/lzma/C/7zTypes.h"
#include "../utils/lzma/C/LzmaEnc.h"
#include "../utils/lzma/C/LzmaDec.h"
// Ugly define to let us forward declare the anonymous-struct-typedef that is CLzmaDec in the header.
#define CLzmaDec_t CLzmaDec
#include "tier1/lzmaDecoder.h"
#include "tier1/convar.h"
// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"
#ifdef OSX
// OS X is having fragmentation issues, and I suspect this 16meg buffer being recreated many times during load is
// hitting a bad case in the default allocator. So this is an experiment to see if it reduces crash rates there.
#define LZMA_DEFAULT_PERSISTENT_BUFFER "1"
#else
#define LZMA_DEFAULT_PERSISTENT_BUFFER "0"
#endif
ConVar lzma_persistent_buffer( "lzma_persistent_buffer", LZMA_DEFAULT_PERSISTENT_BUFFER, FCVAR_NONE,
"If set, attempt to keep a persistent buffer for the LZMA decoder dictionary. " \
"This avoids re-allocating a ~16-64meg buffer for each operation, " \
"at the expensive of keeping extra memory around when it is not in-use." );
// Allocator to pass to LZMA functions
static void *g_pStaticLZMABuf = NULL;
static size_t g_unStaticLZMABufSize = 0;
static uint32 g_unStaticLZMABufRef = 0;
static void *SzAlloc(void *p, size_t size) {
// Don't touch static buffer on other threads.
if ( ThreadInMainThread() )
{
// If nobody is using the persistent buffer and size is above a threshold, use it.
bool bPersistentBuf = (g_pStaticLZMABuf || lzma_persistent_buffer.GetBool()) && size >= (1024 * 1024 * 8) && g_unStaticLZMABufRef == 0;
if ( bPersistentBuf )
{
if ( g_unStaticLZMABufSize < size )
{
g_pStaticLZMABuf = g_pStaticLZMABuf ? realloc( g_pStaticLZMABuf, size ) : malloc( size );
g_unStaticLZMABufSize = size;
}
g_unStaticLZMABufRef++;
return g_pStaticLZMABuf;
}
}
// Not using the persistent buffer
return malloc(size);
}
static void SzFree(void *p, void *address) {
// Don't touch static buffer on other threads.
if ( ThreadInMainThread() )
{
if ( address != NULL && g_unStaticLZMABufRef && address == g_pStaticLZMABuf )
{
g_unStaticLZMABufRef--;
// If the convar was turned off, free the buffer
if ( g_pStaticLZMABuf && g_unStaticLZMABufRef == 0 && !lzma_persistent_buffer.GetBool() )
{
free( g_pStaticLZMABuf );
g_pStaticLZMABuf = NULL;
g_unStaticLZMABufSize = 0;
}
return;
}
}
// Not the static buffer
free(address);
}
static ISzAlloc g_Alloc = { SzAlloc, SzFree };
//-----------------------------------------------------------------------------
// Returns true if buffer is compressed.
//-----------------------------------------------------------------------------
/* static */
bool CLZMA::IsCompressed( unsigned char *pInput )
{
lzma_header_t *pHeader = (lzma_header_t *)pInput;
if ( pHeader && pHeader->id == LZMA_ID )
{
return true;
}
// unrecognized
return false;
}
//-----------------------------------------------------------------------------
// Returns uncompressed size of compressed input buffer. Used for allocating output
// buffer for decompression. Returns 0 if input buffer is not compressed.
//-----------------------------------------------------------------------------
/* static */
unsigned int CLZMA::GetActualSize( unsigned char *pInput )
{
lzma_header_t *pHeader = (lzma_header_t *)pInput;
if ( pHeader && pHeader->id == LZMA_ID )
{
return LittleLong( pHeader->actualSize );
}
// unrecognized
return 0;
}
//-----------------------------------------------------------------------------
// Uncompress a buffer, Returns the uncompressed size. Caller must provide an
// adequate sized output buffer or memory corruption will occur.
//-----------------------------------------------------------------------------
/* static */
unsigned int CLZMA::Uncompress( unsigned char *pInput, unsigned char *pOutput )
{
lzma_header_t *pHeader = (lzma_header_t *)pInput;
if ( pHeader->id != LZMA_ID )
{
// not ours
return false;
}
CLzmaDec state;
LzmaDec_Construct(&state);
if ( LzmaDec_Allocate(&state, pHeader->properties, LZMA_PROPS_SIZE, &g_Alloc) != SZ_OK )
{
Assert( false );
return 0;
}
// These are in/out variables
SizeT outProcessed = LittleLong(pHeader->actualSize);
SizeT inProcessed = LittleLong(pHeader->lzmaSize);
ELzmaStatus status;
SRes result = LzmaDecode( (Byte *)pOutput, &outProcessed, (Byte *)(pInput + sizeof( lzma_header_t ) ),
&inProcessed, (Byte *)pHeader->properties, LZMA_PROPS_SIZE, LZMA_FINISH_END, &status, &g_Alloc );
LzmaDec_Free(&state, &g_Alloc);
if ( result != SZ_OK || LittleLong(pHeader->actualSize) != outProcessed )
{
Warning( "LZMA Decompression failed (%i)\n", result );
return 0;
}
return outProcessed;
}
CLZMAStream::CLZMAStream()
: m_pDecoderState( NULL ),
m_nActualSize( 0 ),
m_nActualBytesRead ( 0 ),
m_nCompressedSize( 0 ),
m_nCompressedBytesRead ( 0 ),
m_bParsedHeader( false ),
m_bZIPStyleHeader( false )
{}
CLZMAStream::~CLZMAStream()
{
FreeDecoderState();
}
void CLZMAStream::FreeDecoderState()
{
if ( m_pDecoderState )
{
LzmaDec_Free( m_pDecoderState, &g_Alloc );
delete m_pDecoderState;
m_pDecoderState = NULL;
}
}
bool CLZMAStream::CreateDecoderState( const unsigned char *pProperties )
{
CLzmaDec *pDecoderState = new CLzmaDec();
LzmaDec_Construct( pDecoderState );
if ( LzmaDec_Allocate( pDecoderState, pProperties, LZMA_PROPS_SIZE, &g_Alloc) != SZ_OK )
{
AssertMsg( false, "Failed to allocate lzma decoder state" );
delete pDecoderState;
return false;
}
LzmaDec_Init( pDecoderState );
// Replace current state
Assert( !m_pDecoderState );
FreeDecoderState();
m_pDecoderState = pDecoderState;
return true;
}
// Attempt to read up to nMaxInputBytes from the compressed stream, writing up to nMaxOutputBytes to pOutput.
// Returns false if read stops due to an error.
bool CLZMAStream::Read( unsigned char *pInput, unsigned int nMaxInputBytes,
unsigned char *pOutput, unsigned int nMaxOutputBytes,
/* out */ unsigned int &nCompressedBytesRead,
/* out */ unsigned int &nOutputBytesWritten )
{
nCompressedBytesRead = 0;
nOutputBytesWritten = 0;
bool bStartedWithHeader = m_bParsedHeader;
// Check for initial chunk of data
if ( !m_bParsedHeader )
{
unsigned int nBytesConsumed = 0;
eHeaderParse parseResult = TryParseHeader( pInput, nMaxInputBytes, nBytesConsumed );
if ( parseResult == eHeaderParse_NeedMoreBytes )
{
// Not an error, just need more data to continue
return true;
}
else if ( parseResult != eHeaderParse_OK )
{
Assert( parseResult == eHeaderParse_Fail );
// Invalid header
return false;
}
// Header consumed, fall through to continue read after it
nCompressedBytesRead += nBytesConsumed;
pInput += nBytesConsumed;
nMaxInputBytes -= nBytesConsumed;
}
// These are input ( available size ) *and* output ( size processed ) vars for lzma
SizeT expectedInputRemaining = m_nCompressedSize - Min( m_nCompressedBytesRead + nCompressedBytesRead, m_nCompressedSize );
SizeT expectedOutputRemaining = m_nActualSize - m_nActualBytesRead;
SizeT inSize = Min( (SizeT)nMaxInputBytes, expectedInputRemaining );
SizeT outSize = Min( (SizeT)nMaxOutputBytes, expectedOutputRemaining );
ELzmaStatus status;
ELzmaFinishMode finishMode = LZMA_FINISH_ANY;
if ( inSize == expectedInputRemaining && outSize == expectedOutputRemaining )
{
// Expect to finish decoding this call.
finishMode = LZMA_FINISH_END;
}
SRes result = LzmaDec_DecodeToBuf( m_pDecoderState, pOutput, &outSize,
pInput, &inSize, finishMode, &status );
// DevMsg("[%p] Running lzmaDecode:\n"
// " pInput: %p\n"
// " nMaxInputBytes: %i\n"
// " pOutput: %p\n"
// " nMaxOutputBytes: %u\n"
// " inSize: %u\n"
// " outSize: %u\n"
// " result: %u\n"
// " status: %i\n"
// " m_nActualSize: %u\n"
// " m_nActualBytesRead: %u\n",
// this, pInput, nMaxInputBytes, pOutput, nMaxOutputBytes,
// inSize, outSize, result, status, m_nActualSize, m_nActualBytesRead);
if ( result != SZ_OK )
{
if ( !bStartedWithHeader )
{
// If we're returning false, we need to pretend we didn't consume anything.
FreeDecoderState();
m_bParsedHeader = false;
}
return false;
}
nCompressedBytesRead += inSize;
nOutputBytesWritten += outSize;
m_nCompressedBytesRead += nCompressedBytesRead;
m_nActualBytesRead += nOutputBytesWritten;
Assert( m_nCompressedBytesRead <= m_nCompressedSize );
return true;
}
bool CLZMAStream::GetExpectedBytesRemaining( /* out */ unsigned int &nBytesRemaining )
{
if ( !m_bParsedHeader && !m_bZIPStyleHeader ) {
return false;
}
nBytesRemaining = m_nActualSize - m_nActualBytesRead;
return true;
}
void CLZMAStream::InitZIPHeader( unsigned int nCompressedSize, unsigned int nOriginalSize )
{
if ( m_bParsedHeader || m_bZIPStyleHeader )
{
AssertMsg( !m_bParsedHeader && !m_bZIPStyleHeader,
"LZMA Stream: InitZIPHeader() called on stream past header" );
return;
}
m_nCompressedSize = nCompressedSize;
m_nActualSize = nOriginalSize;
// Signal to TryParseHeader to expect a zip-style header (which wont have the size values)
m_bZIPStyleHeader = true;
}
CLZMAStream::eHeaderParse CLZMAStream::TryParseHeader( unsigned char *pInput, unsigned int nBytesAvailable, /* out */ unsigned int &nBytesConsumed )
{
nBytesConsumed = 0;
if ( m_bParsedHeader )
{
AssertMsg( !m_bParsedHeader, "CLZMAStream::ReadSourceHeader called on already initialized stream" );
return eHeaderParse_Fail;
}
if ( m_bZIPStyleHeader )
{
// ZIP Spec, 5.8.8
// LZMA Version Information 2 bytes
// LZMA Properties Size 2 bytes
// LZMA Properties Data variable, defined by "LZMA Properties Size"
if ( nBytesAvailable < 4 )
{
// No error, but need more input to continue
return eHeaderParse_NeedMoreBytes;
}
// Should probably check this
// unsigned char nLZMAVer[2] = { pInput[0], pInput[1] };
uint16 nLZMAPropertiesSize = LittleWord( *(uint16 *)(pInput + 2) );
nBytesConsumed += 4;
if ( nLZMAPropertiesSize != LZMA_PROPS_SIZE )
{
Warning( "LZMA stream: Unexpected LZMA properties size: %hu, expecting %u. Version mismatch?\n",
nLZMAPropertiesSize, LZMA_PROPS_SIZE );
return eHeaderParse_Fail;
}
if ( nBytesAvailable < static_cast<unsigned int>(nLZMAPropertiesSize) + 4 )
{
return eHeaderParse_NeedMoreBytes;
}
// Looks reasonable, try to parse
if ( !CreateDecoderState( (Byte *)pInput + 4 ) )
{
AssertMsg( false, "Failed decoding Lzma properties" );
return eHeaderParse_Fail;
}
nBytesConsumed += nLZMAPropertiesSize;
}
else
{
// Else native source engine style header
if ( nBytesAvailable < sizeof( lzma_header_t ) )
{
// need more input to continue
return eHeaderParse_NeedMoreBytes;
}
m_nActualSize = CLZMA::GetActualSize( pInput );
if ( !m_nActualSize )
{
// unrecognized
Warning( "Unrecognized LZMA data\n" );
return eHeaderParse_Fail;
}
if ( !CreateDecoderState( ((lzma_header_t *)pInput)->properties ) )
{
AssertMsg( false, "Failed decoding Lzma properties" );
return eHeaderParse_Fail;
}
m_nCompressedSize = LittleLong( ((lzma_header_t *)pInput)->lzmaSize ) + sizeof( lzma_header_t );
nBytesConsumed += sizeof( lzma_header_t );
}
m_bParsedHeader = true;
return eHeaderParse_OK;
}