/*
 * Copyright © 1999-2001 NCSA
 *                       All rights reserved.
 *
 * Programmer:  Robb Matzke <matzke@llnl.gov>
 *              Friday, August 27, 1999
 */
#include "H5private.h"
#include "H5Eprivate.h"
#include "H5MMprivate.h"
#include "H5Zprivate.h"

#ifdef H5_HAVE_ZLIB_H
#   include "zlib.h"
#else
/* Make sure compression is disabled too. */
#undef H5_HAVE_COMPRESSION
#endif

/* Interface initialization */
#define PABLO_MASK	H5Z_deflate_mask
#define INTERFACE_INIT	NULL
static int interface_initialize_g = 0;


/*-------------------------------------------------------------------------
 * Function:	H5Z_filter_deflate
 *
 * Purpose:	
 *
 * Return:	Success:	
 *
 *		Failure:	
 *
 * Programmer:	Robb Matzke
 *              Thursday, April 16, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
size_t
#if defined(H5_HAVE_COMPRESSION)
H5Z_filter_deflate (unsigned flags, size_t cd_nelmts,
		    const unsigned cd_values[], size_t nbytes,
		    size_t *buf_size, void **buf)
#else
H5Z_filter_deflate (unsigned UNUSED flags, size_t cd_nelmts,
		    const unsigned cd_values[], size_t UNUSED nbytes,
		    size_t * UNUSED buf_size, void ** UNUSED buf)
#endif
{
    size_t	ret_value = 0;
    void	*outbuf = NULL;
#if defined(H5_HAVE_COMPRESSION)
    int		aggression = 6;
    int		status;
#endif
    
    FUNC_ENTER_NOAPI(H5Z_filter_deflate, 0);

    /* Check arguments */
    if (cd_nelmts!=1 || cd_values[0]>9) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, 0,
		    "invalid deflate aggression level");
    }

#if defined(H5_HAVE_COMPRESSION)
    aggression = cd_values[0];
    if (flags & H5Z_FLAG_REVERSE) {
	/* Input; uncompress */
	z_stream	z_strm;
	size_t		nalloc = *buf_size;

	if (NULL==(outbuf = H5MM_malloc(nalloc))) {
	    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, 0,
			"memory allocation failed for deflate uncompression");
	}
	HDmemset(&z_strm, 0, sizeof(z_strm));
	z_strm.next_in = *buf;
        H5_ASSIGN_OVERFLOW(z_strm.avail_in,nbytes,size_t,uInt);
	z_strm.next_out = outbuf;
        H5_ASSIGN_OVERFLOW(z_strm.avail_out,nalloc,size_t,uInt);
	if (Z_OK!=inflateInit(&z_strm)) {
	    HGOTO_ERROR(H5E_PLINE, H5E_CANTINIT, 0, "inflateInit() failed");
	}
	while (1) {
	    status = inflate(&z_strm, Z_SYNC_FLUSH);
	    if (Z_STREAM_END==status) break;	/*done*/
	    if (Z_OK!=status) {
		inflateEnd(&z_strm);
		HGOTO_ERROR(H5E_PLINE, H5E_CANTINIT, 0, "inflate() failed");
	    }
	    if (Z_OK==status && 0==z_strm.avail_out) {
		nalloc *= 2;
		if (NULL==(outbuf = H5MM_realloc(outbuf, nalloc))) {
		    inflateEnd(&z_strm);
		    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, 0,
				"memory allocation failed for deflate "
				"uncompression");
		}
		z_strm.next_out = (unsigned char*)outbuf + z_strm.total_out;
		z_strm.avail_out = (uInt)(nalloc - z_strm.total_out);
	    }
	}
	
	H5MM_xfree(*buf);
	*buf = outbuf;
	outbuf = NULL;
	*buf_size = nalloc;
	ret_value = z_strm.total_out;
	inflateEnd(&z_strm);
	
    } else {
	/*
	 * Output; compress but fail if the result would be larger than the
	 * input.  The library doesn't provide in-place compression, so we
	 * must allocate a separate buffer for the result.
	 */
	const Bytef	*z_src = (const Bytef*)(*buf);
	Bytef		*z_dst;		/*destination buffer		*/
	uLongf		z_dst_nbytes = (uLongf)nbytes;
	uLong		z_src_nbytes = (uLong)nbytes;

	if (NULL==(z_dst=outbuf=H5MM_malloc(nbytes))) {
	    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, 0,
			"unable to allocate deflate destination buffer");
	}
	status = compress2 (z_dst, &z_dst_nbytes, z_src, z_src_nbytes,
			    aggression);
	if (Z_BUF_ERROR==status) {
	    HGOTO_ERROR(H5E_PLINE, H5E_CANTINIT, 0, "overflow");
	} else if (Z_MEM_ERROR==status) {
	    HGOTO_ERROR (H5E_PLINE, H5E_CANTINIT, 0, "deflate memory error");
	} else if (Z_OK!=status) {
	    HGOTO_ERROR (H5E_PLINE, H5E_CANTINIT, 0, "deflate error");
	} else {
	    H5MM_xfree(*buf);
	    *buf = outbuf;
	    outbuf = NULL;
	    *buf_size = nbytes;
	    ret_value = z_dst_nbytes;
	}
    }
#else
    HGOTO_ERROR (H5E_PLINE, H5E_UNSUPPORTED, 0,
		 "hdf5 was not compiled with zlib-1.0.2 or better");
#endif

done:
    if(outbuf)
        H5MM_xfree(outbuf);
    FUNC_LEAVE (ret_value);
}