CnC_Remastered_Collection

LZWPIPE.CPP (14784B)

---

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 /* $Header: /CounterStrike/LZWPIPE.CPP 1     3/03/97 10:25a Joe_bostic $ */
 /***********************************************************************************************
  ***              C O N F I D E N T I A L  ---  W E S T W O O D  S T U D I O S               ***
  ***********************************************************************************************
  *                                                                                             *
  *                 Project Name : Command & Conquer                                            *
  *                                                                                             *
  *                    File Name : LZWPIPE.CPP                                                  *
  *                                                                                             *
  *                   Programmer : Joe L. Bostic                                                *
  *                                                                                             *
  *                   Start Date : 06/30/96                                                     *
  *                                                                                             *
  *                  Last Update : July 4, 1996 [JLB]                                           *
  *                                                                                             *
  *---------------------------------------------------------------------------------------------*
  * Functions:                                                                                  *
  *   LZWPipe::Flush -- Flushes any partially accumulated block.                                *
  *   LZWPipe::LZWPipe -- Constructor for the LZW processor pipe.                               *
  *   LZWPipe::Put -- Send some data through the LZW processor pipe.                            *
  *   LZWPipe::~LZWPipe -- Deconstructor for the LZW pipe object.                               *
  * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 
 #include	"lzwpipe.h"
 #include	"lzw.h"
 #include	"buff.h"
 #include	<string.h>
 #include	<assert.h>
 
 
 /***********************************************************************************************
  * LZWPipe::LZWPipe -- Constructor for the LZW processor pipe.                                 *
  *                                                                                             *
  *    This will initialize the LZWPipe object so that it is prepared for compression or        *
  *    decompression as indicated.                                                              *
  *                                                                                             *
  * INPUT:   decrypt  -- Should decompression be performed?                                     *
  *                                                                                             *
  *          blocksize-- The size of the data blocks to process.                                *
  *                                                                                             *
  * OUTPUT:  none                                                                               *
  *                                                                                             *
  * WARNINGS:   none                                                                            *
  *                                                                                             *
  * HISTORY:                                                                                    *
  *   07/04/1996 JLB : Created.                                                                 *
  *=============================================================================================*/
 LZWPipe::LZWPipe(CompControl control, int blocksize) :
 		Control(control),
 		Counter(0),
 		Buffer(NULL),
 		Buffer2(NULL),
 		BlockSize(blocksize)
 {
 	SafetyMargin = BlockSize;
 //	SafetyMargin = BlockSize/128+1;
 	Buffer = new char[BlockSize+SafetyMargin];
 	Buffer2 = new char[BlockSize+SafetyMargin];
 	BlockHeader.CompCount = 0xFFFF;
 }
 
 
 /***********************************************************************************************
  * LZWPipe::~LZWPipe -- Deconstructor for the LZW pipe object.                                 *
  *                                                                                             *
  *    This will free any buffers it may have allocated.                                        *
  *                                                                                             *
  * INPUT:   none                                                                               *
  *                                                                                             *
  * OUTPUT:  none                                                                               *
  *                                                                                             *
  * WARNINGS:   none                                                                            *
  *                                                                                             *
  * HISTORY:                                                                                    *
  *   07/04/1996 JLB : Created.                                                                 *
  *=============================================================================================*/
 LZWPipe::~LZWPipe(void)
 {
 	delete [] Buffer;
 	Buffer = NULL;
 
 	delete [] Buffer2;
 	Buffer2 = NULL;
 }
 
 
 /***********************************************************************************************
  * LZWPipe::Put -- Send some data through the LZW processor pipe.                              *
  *                                                                                             *
  *    This routine will take the data requested and process it (decompression or compression). *
  *    It does this by accumulating the necessary bytes to make a whole block. Then the block   *
  *    is processed and the entire contents are flushed to the next pipe segment in the chain.  *
  *                                                                                             *
  * INPUT:   source   -- Pointer to the data to be fed to this LZW processor.                   *
  *                                                                                             *
  *          length   -- The number of bytes received.                                          *
  *                                                                                             *
  * OUTPUT:  Returns with the actual number of bytes output at the far distant final link in    *
  *          the pipe chain.                                                                    *
  *                                                                                             *
  * WARNINGS:   The compression process may be slow as well as consuming two buffers.           *
  *                                                                                             *
  * HISTORY:                                                                                    *
  *   07/04/1996 JLB : Created.                                                                 *
  *=============================================================================================*/
 int LZWPipe::Put(void const * source, int slen)
 {
 	if (source == NULL || slen < 1) {
 		return(Pipe::Put(source, slen));
 	}
 
 	assert(Buffer != NULL);
 
 	int total = 0;
 
 	/*
 	**	Copy as much as can fit into the buffer from the source data supplied.
 	*/
 	if (Control ==  DECOMPRESS) {
 
 		while (slen > 0) {
 
 			/*
 			**	First check to see if we are in the block header accumulation phase.
 			**	When a whole block header has been accumulated, only then will the regular
 			**	data processing begin for the block.
 			*/
 			if (BlockHeader.CompCount == 0xFFFF) {
 				int len = (slen < ((int)sizeof(BlockHeader)-Counter)) ? slen : (sizeof(BlockHeader)-Counter);
 				memmove(&Buffer[Counter], source, len);
 				source = ((char *)source) + len;
 				slen -= len;
 				Counter += len;
 
 				/*
 				**	A whole block header has been accumulated. Store it for safekeeping.
 				*/
 				if (Counter == sizeof(BlockHeader)) {
 					memmove(&BlockHeader, Buffer, sizeof(BlockHeader));
 					Counter = 0;
 				}
 			}
 
 			/*
 			**	Fill the buffer with compressed data until there is enough to make a whole
 			**	data block.
 			*/
 			if (slen > 0) {
 				int len = (slen < (BlockHeader.CompCount-Counter)) ? slen : (BlockHeader.CompCount-Counter);
 
 				memmove(&Buffer[Counter], source, len);
 				slen -= len;
 				source = ((char *)source) + len;
 				Counter += len;
 
 				/*
 				**	If an entire block has been accumulated, then uncompress it and feed it
 				**	through the pipe.
 				*/
 				if (Counter == BlockHeader.CompCount) {
 					LZW_Uncompress(Buffer, Buffer2);
 					total += Pipe::Put(Buffer2, BlockHeader.UncompCount);
 					Counter = 0;
 					BlockHeader.CompCount = 0xFFFF;
 				}
 			}
 		}
 
 	} else {
 
 		/*
 		**	If the buffer already contains some data, then any new data must be stored
 		**	into the staging buffer until a full set has been accumulated.
 		*/
 		if (Counter > 0) {
 			int tocopy = (slen < (BlockSize-Counter)) ? slen : (BlockSize-Counter);
 			memmove(&Buffer[Counter], source, tocopy);
 			source = ((char *)source) + tocopy;
 			slen -= tocopy;
 			Counter += tocopy;
 
 			if (Counter == BlockSize) {
 				int len = LZW_Compress(::Buffer(Buffer, BlockSize), Buffer2);
 
 				BlockHeader.CompCount = (unsigned short)len;
 				BlockHeader.UncompCount = (unsigned short)BlockSize;
 				total += Pipe::Put(&BlockHeader, sizeof(BlockHeader));
 				total += Pipe::Put(Buffer2, len);
 				Counter = 0;
 			}
 		}
 
 		/*
 		**	Process the source data in whole block chunks until there is insufficient
 		**	source data left for a whole data block.
 		*/
 		while (slen >= BlockSize) {
 			int len = LZW_Compress(::Buffer((void*)source, BlockSize), Buffer2);
 
 			source = ((char *)source) + BlockSize;
 			slen -= BlockSize;
 
 			BlockHeader.CompCount = (unsigned short)len;
 			BlockHeader.UncompCount = (unsigned short)BlockSize;
 			total += Pipe::Put(&BlockHeader, sizeof(BlockHeader));
 			total += Pipe::Put(Buffer2, len);
 		}
 
 		/*
 		**	If there is any remaining data, then it is stored into the buffer
 		**	until a full data block has been accumulated.
 		*/
 		if (slen > 0) {
 			memmove(Buffer, source, slen);
 			Counter = slen;
 		}
 	}
 
 	return(total);
 }
 
 
 /***********************************************************************************************
  * LZWPipe::Flush -- Flushes any partially accumulated block.                                  *
  *                                                                                             *
  *    This routine is called when any buffered data must be flushed out the pipe. For the      *
  *    compression process, this will generate the sub-sized compressed block. For              *
  *    decompression, this routine should not have any data in the buffer. In such a case, it   *
  *    means that the data source was prematurely truncated. In such a case, just dump the      *
  *    accumulated data through the pipe.                                                       *
  *                                                                                             *
  * INPUT:   none                                                                               *
  *                                                                                             *
  * OUTPUT:  Returns with the actual number of data bytes output to the distant final link in   *
  *          the pipe chain.                                                                    *
  *                                                                                             *
  * WARNINGS:   none                                                                            *
  *                                                                                             *
  * HISTORY:                                                                                    *
  *   07/04/1996 JLB : Created.                                                                 *
  *=============================================================================================*/
 int LZWPipe::Flush(void)
 {
 	assert(Buffer != NULL);
 
 	int total = 0;
 
 	/*
 	**	If there is accumulated data, then it must processed.
 	*/
 	if (Counter > 0) {
 		if (Control == DECOMPRESS) {
 
 			/*
 			**	If the accumulated data is insufficient to make a block header, then
 			**	this means the data has been truncated. Just dump the data through
 			**	as if were already decompressed.
 			*/
 			if (BlockHeader.CompCount == 0xFFFF) {
 				total += Pipe::Put(Buffer, Counter);
 				Counter = 0;
 			}
 
 			/*
 			**	There appears to be a partial block accumulated in the buffer. It would
 			**	be disastrous to try to decompress the data since there wouldn't be
 			**	the special end of data code that LZW decompression needs. In this
 			**	case, dump the data out as if it were already decompressed.
 			*/
 			if (Counter > 0) {
 				total += Pipe::Put(&BlockHeader, sizeof(BlockHeader));
 				total += Pipe::Put(Buffer, Counter);
 				Counter = 0;
 				BlockHeader.CompCount = 0xFFFF;
 			}
 
 		} else {
 
 			/*
 			**	A partial block in the compression process is a normal occurrence. Just
 			**	compress the partial block and output normally.
 			*/
 			int len = LZW_Compress(::Buffer(Buffer, Counter), Buffer2);
 
 			BlockHeader.CompCount = (unsigned short)len;
 			BlockHeader.UncompCount = (unsigned short)Counter;
 			total += Pipe::Put(&BlockHeader, sizeof(BlockHeader));
 			total += Pipe::Put(Buffer2, len);
 			Counter = 0;
 		}
 	}
 
 	total += Pipe::Flush();
 	return(total);
 }