/*
 * This file is a part of CMSLU -- Content Management System like Unix
 * and is not publicly distributed
 * 
 * Copyright (c) 2008-2009, Tomasz Sowa
 * All rights reserved.
 * 
 */
 
#include "compress.h"
#include "log.h"




Compress::Compress()
{
	buffer = 0;
	buffer_max_len = 65536; // 64KB
	ready_for_compress = false;
}


Compress::~Compress()
{
	if( buffer )
		delete [] buffer;
}


bool Compress::AllocateMemory()
{
	if( buffer )
		delete [] buffer;
	
	
	try 
	{
		buffer = new char[buffer_max_len];
	}
	catch(const std::bad_alloc &)
	{
		log << log1 << "Compress: can't allocate memory" << logend;
		
		buffer = 0;
		return false;	
	}
	
return true;
}


/*
	return:
	0 - ok;
	1 - can't allocate memory
	100 - unknown
*/
int Compress::Init(int compress_level)
{
	if( buffer == 0 )
		if( !AllocateMemory() )
			return 1;
	
	strm.zalloc = Z_NULL;
	strm.zfree  = Z_NULL;
	strm.opaque = Z_NULL;
	int ret = deflateInit(&strm, compress_level);
	
	if( ret != Z_OK )
		log << log1 << "Compress: problem with deflateInit()" << logend;
	
	if( ret == Z_MEM_ERROR )
		return 1;
	
	if( ret != Z_OK )
		return 100;

	ready_for_compress = true;

return 0;
}


int Compress::MakeCompress(const char * source, size_t source_len, FCGX_Stream * out_stream)
{
int ret, flush;
size_t have;

	do
	{
		strm.avail_in = (source_len > buffer_max_len) ? buffer_max_len : source_len;
		source_len   -= strm.avail_in;
		flush         = (source_len == 0) ? Z_FINISH : Z_NO_FLUSH;
		strm.next_in  = (Bytef*)source;
		source       += strm.avail_in;
		
		do
		{
			strm.avail_out = buffer_max_len;
			strm.next_out  = (Bytef*)buffer;
			ret = deflate(&strm, flush);
			
			if( ret == Z_STREAM_ERROR || ret == Z_BUF_ERROR )
			{
				log << log1 << "Compress: problem with deflate()" << logend;
				return 2;
			}
			
			have = buffer_max_len - strm.avail_out;
			last_out_size += have;
			FCGX_PutStr(buffer, have, out_stream);
		}
		while( strm.avail_out == 0 );
		
		if( strm.avail_in != 0 )
		{
			log << log1 << "Compress: problem with deflate() - not all input is used" << logend;
			return 2;
		}
	}
	while( flush != Z_FINISH );
	
	
	if( ret != Z_STREAM_END )
	{
		log << log1 << "Compress: problem with deflate() - stream not complete" << logend;
		return 2;
	}
		
return 0;
}




/*
	return:
	0 - ok;
	1 - can't allocate memory
	2 - error during compressing
	3 - not inited (use Init() first)
	100 - unknown
*/
int Compress::CompressAndPut(const char * source, size_t source_len, FCGX_Stream * out_stream, int level)
{
int ret;
	
	last_out_size = 0;
	
	if( !ready_for_compress )
	{
		log << log1 << "Compress: not ready yet" << logend;
		return 3;
	}
	
	if( source_len == 0 )
		return 0;
	
	ret = MakeCompress(source, source_len, out_stream);
	
	if( deflateReset(&strm) != Z_OK )
		log << log1 << "Compress: problem with deflateReset()" << logend;

	double ratio = 100.0 - (double(last_out_size) / double(source_len) * 100.0);
	char buffer[30];
	sprintf(buffer, "%.1f", ratio);
	
	log << log2 << "Compress: original size: " << source_len << ", compress size: " << (int)last_out_size << ", ratio: " << buffer << "%" << logend;
	
return ret;
}