/* 31/01/01 Libtiny compression/decompression library v1.0
		Compression routine using zlib deflate
		Deflate code:	deflate 1.1.3 Copyright 1995-1998 Jean-loup Gailly */

/* includes */
#include	<libps.h>
#include	"stdio.h"

#include	"zlib.h"
#include	"zconf.h"

#include	"tiny.h"

/* globals */
	

/* Compress data using zlib deflate routines,
		*source_p - pointer to  data to compress,
		sourcelen - number of bytes to compress,
		destination_p - pointer to buffer to store compressed data
	 Return values
	 	>0							compressed data size in bytes, including header,
		 0(T_LEN_ERROR)	sourcelen is zero,
	 	-2(T_MEM_ERROR)	out of memory, workspace couldn't be allocated,
		-3(T_BUF_ERROR) destination buffer too small, this error is returned if the data cannot 
		                be compressed, 
	The destination buffer length should be 0.1% plus 32 bytes larger than the source data length*/	
int	z_compress(u_char	*source_p, u_int	sourcelen, u_char *destination_p)
{
	S_HDR	*header_p = (S_HDR *)destination_p;
	u_int	destlen;
	int	status = T_LEN_ERROR;

	if(sourcelen)
	{
		header_p->id = ID_ZLIB;										
		header_p->orig_size = sourcelen;
	
		destination_p += sizeof(S_HDR);				/* start of compression data after header */
	
 		destlen = sourcelen + (sourcelen * 0.001) + 12;		/* minimum destination buffer size */
	
		status = compress((Bytef *)destination_p,(uLongf *)&destlen,(Bytef *)source_p,(uLong)sourcelen);
	
		switch(status)
		{
			case	Z_OK:
				header_p->comp_size = destlen;							/* store compressed data size in header */
				status = (int) destlen + sizeof(S_HDR);						/* add header size to total */
				break;
			case	Z_MEM_ERROR:			/* work space could not be allocated */
				status = T_MEM_ERROR;
				break;
			case	Z_BUF_ERROR:			/* compressed data buffer too small */
				status = T_BUF_ERROR;	/* probably trying to compress data that's already compressed */
		}
	}

	return status;
}