/*
 * Copyright (C) 1998 Spizella Software
 *                    All rights reserved.
 *
 * Programmer:  Robb Matzke <robb@arborea.spizella.com>
 *              Tuesday, January 13, 1998
 *
 * Purpose:     Data type conversions.
 */
#define H5T_PACKAGE             /*suppress error about including H5Tpkg   */

#include <H5Iprivate.h>
#include <H5Eprivate.h>
#include <H5MMprivate.h>
#include <H5Tpkg.h>

/* Conversion data for H5T_conv_struct() */
typedef struct H5T_conv_struct_t {
    intn	*src2dst;		/*mapping from src to dst memb ID    */
    hid_t	*src_memb_id;		/*source member type ID's	     */
    hid_t	*dst_memb_id;		/*destination member type ID's	     */
    H5T_conv_t	*memb_conv;		/*array of membr conversion functions*/
    H5T_cdata_t	**memb_cdata;		/*array of member cdata pointers     */
} H5T_conv_struct_t;

/* Interface initialization */
static intn interface_initialize_g = FALSE;
#define INTERFACE_INIT NULL

/*-------------------------------------------------------------------------
 * Function:    H5T_conv_noop
 *
 * Purpose:     The no-op conversion.  The library knows about this
 *              conversion without it being registered.
 *
 * Return:      Success:        SUCCEED
 *
 *              Failure:        never fails
 *
 * Programmer:  Robb Matzke
 *              Wednesday, January 14, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5T_conv_noop(hid_t src_id, hid_t dst_id, H5T_cdata_t *cdata, size_t nelmts,
              void *buf, void *background)
{
    FUNC_ENTER(H5T_conv_noop, FAIL);

    switch (cdata->command) {
    case H5T_CONV_INIT:
	/* Nothing to initialize */
	break;

    case H5T_CONV_CONV:
	/* Nothing to convert */
	break;

    case H5T_CONV_FREE:
	/* Nothing to free */
#ifdef H5T_DEBUG
	if (cdata->ncalls>0) {
	    fprintf (stderr, "H5T: H5T_conv_noop statistics...\n");
	    fprintf (stderr, "   Number of calls:       %lu\n", cdata->ncalls);
	    fprintf (stderr, "   Data points converted: %lu\n", cdata->nelmts);
	}
#endif

    default:
	HRETURN_ERROR (H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
		       "unknown conversion command");
    }

    FUNC_LEAVE(SUCCEED);
}

/*-------------------------------------------------------------------------
 * Function:    H5T_conv_order
 *
 * Purpose:     Convert one type to another when byte order is the only
 *              difference.
 *
 * Note:        This is a soft conversion function.
 *
 * Return:      Success:        SUCCEED
 *
 *              Failure:        FAIL
 *
 * Programmer:  Robb Matzke
 *              Tuesday, January 13, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5T_conv_order(hid_t src_id, hid_t dst_id, H5T_cdata_t *cdata, size_t nelmts,
               void *_buf, void *background)
{
    uint8       *buf = (uint8 *) _buf;
    uint8       tmp;
    H5T_t       *src = NULL;
    H5T_t       *dst = NULL;
    size_t	i, j, md;

    FUNC_ENTER(H5T_conv_order, FAIL);

    switch (cdata->command) {
    case H5T_CONV_INIT:
        /* Capability query */
	if (H5_DATATYPE != H5I_group(src_id) ||
	    NULL == (src = H5I_object(src_id)) ||
	    H5_DATATYPE != H5I_group(dst_id) ||
	    NULL == (dst = H5I_object(dst_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a data type");
	}
        if (src->size != dst->size ||
            0 != src->u.atomic.offset ||
            0 != dst->u.atomic.offset ||
            !((H5T_ORDER_BE == src->u.atomic.order &&
               H5T_ORDER_LE == dst->u.atomic.order) ||
              (H5T_ORDER_LE == src->u.atomic.order &&
               H5T_ORDER_BE == dst->u.atomic.order))) {
            HRETURN_ERROR(H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
                          "conversion not supported");
        }
        switch (src->type) {
        case H5T_INTEGER:
            /* nothing to check */
            break;

        case H5T_FLOAT:
            if (src->u.atomic.u.f.sign != dst->u.atomic.u.f.sign ||
                src->u.atomic.u.f.epos != dst->u.atomic.u.f.epos ||
                src->u.atomic.u.f.esize != dst->u.atomic.u.f.esize ||
                src->u.atomic.u.f.ebias != dst->u.atomic.u.f.ebias ||
                src->u.atomic.u.f.mpos != dst->u.atomic.u.f.mpos ||
                src->u.atomic.u.f.msize != dst->u.atomic.u.f.msize ||
                src->u.atomic.u.f.norm != dst->u.atomic.u.f.norm ||
                src->u.atomic.u.f.pad != dst->u.atomic.u.f.pad) {
                HRETURN_ERROR(H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
                              "conversion not supported");
            }
            break;

        default:
            HRETURN_ERROR(H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
                          "conversion not supported");
        }
	break;

    case H5T_CONV_CONV:
	/* The conversion */
	if (H5_DATATYPE != H5I_group(src_id) ||
	    NULL == (src = H5I_object(src_id)) ||
	    H5_DATATYPE != H5I_group(dst_id) ||
	    NULL == (dst = H5I_object(dst_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a data type");
	}
	md = src->size / 2;
	for (i=0; i<nelmts; i++, buf+=src->size) {
	    for (j=0; j<md; j++) {
		tmp = buf[j];
		buf[j] = buf[src->size-(j+1)];
		buf[src->size-(j+1)] = tmp;
	    }
	}
	break;

    case H5T_CONV_FREE:
	/* Free private data */
#ifdef H5T_DEBUG
	if (cdata->ncalls>0) {
	    fprintf (stderr, "H5T: H5T_conv_order statistics...\n");
	    fprintf (stderr, "   Number of calls:       %lu\n", cdata->ncalls);
	    fprintf (stderr, "   Data points converted: %lu\n", cdata->nelmts);
	}
#endif
	break;

    default:
	HRETURN_ERROR (H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
		       "unknown conversion command");
    }

    FUNC_LEAVE(SUCCEED);
}

/*-------------------------------------------------------------------------
 * Function:	H5T_conv_struct_init
 *
 * Purpose:	Initialize the `priv' field of `cdata' with conversion
 *		information that is relatively constant.  If `priv' is
 *		already initialized then the member conversion functions
 *		are recalculated.
 *
 * Return:	Success:	SUCCEED
 *
 *		Failure:	FAIL
 *
 * Programmer:	Robb Matzke
 *              Monday, January 26, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T_conv_struct_init (H5T_t *src, H5T_t *dst, H5T_cdata_t *cdata)
{
    H5T_conv_struct_t	*priv = (H5T_conv_struct_t*)(cdata->priv);
    intn		i, j, *src2dst = NULL;
    H5T_t		*type = NULL;
    hid_t		tid;
    
    FUNC_ENTER (H5T_conv_struct_init, FAIL);
    
    if (!priv) {
	/*
	 * Notice: the thing marked with `!' below really is `dst' and not
	 *	   `src' because we're only interested in the members of the
	 * 	   source type that are also in the destination type.
	 */
	cdata->priv = priv = H5MM_xcalloc (1, sizeof(H5T_conv_struct_t));
	priv->src2dst = H5MM_xmalloc (src->u.compnd.nmembs * sizeof(intn));
	priv->src_memb_id = H5MM_xmalloc (/*!*/dst->u.compnd.nmembs *
					  sizeof(hid_t));
	priv->dst_memb_id = H5MM_xmalloc (dst->u.compnd.nmembs *
					  sizeof(hid_t));

	/*
	 * Insure that members are sorted.
	 */
	H5T_sort_by_offset (src);
	H5T_sort_by_offset (dst);

	/*
	 * Build a mapping from source member number to destination member
	 * number. If some source member is not a destination member then that
	 * mapping element will be negative.  Also create atoms for each
	 * source and destination member data type so we can look up the
	 * member data type conversion functions later.
	 */
	for (i=0; i<src->u.compnd.nmembs; i++) {
	    priv->src2dst[i] = -1;
	    for (j=0; j<dst->u.compnd.nmembs; j++) {
		if (!HDstrcmp (src->u.compnd.memb[i].name,
			   dst->u.compnd.memb[j].name)) {
		    priv->src2dst[i] = j;
		    break;
		}
	    }
	    if (priv->src2dst[i]>=0) {
		type = H5T_copy (src->u.compnd.memb[i].type);
		tid = H5I_register (H5_DATATYPE, type);
		assert (tid>=0);
		priv->src_memb_id[priv->src2dst[i]] = tid;

		type = H5T_copy (dst->u.compnd.memb[priv->src2dst[i]].type);
		tid = H5I_register (H5_DATATYPE, type);
		assert (tid>=0);
		priv->dst_memb_id[priv->src2dst[i]] = tid;
	    }
	}
    }

    /*
     * (Re)build the cache of member conversion functions and pointers to
     * their cdata entries.
     */
    priv->memb_conv = H5MM_xfree (priv->memb_conv);
    priv->memb_cdata = H5MM_xfree (priv->memb_cdata);
    priv->memb_conv = H5MM_xmalloc (dst->u.compnd.nmembs *
				    sizeof(H5T_conv_t));
    priv->memb_cdata = H5MM_xcalloc (dst->u.compnd.nmembs,
				     sizeof(H5T_cdata_t*));
    src2dst = priv->src2dst;

    for (i=0; i<src->u.compnd.nmembs; i++) {
	if (priv->src2dst[i]>=0) {
	    H5T_conv_t tconv_func = H5Tfind (priv->src_memb_id[src2dst[i]],
					     priv->dst_memb_id[src2dst[i]],
					     priv->memb_cdata+src2dst[i]);
	    if (!tconv_func) {
		H5MM_xfree (priv->src2dst);
		H5MM_xfree (priv->src_memb_id);
		H5MM_xfree (priv->dst_memb_id);
		H5MM_xfree (priv->memb_conv);
		cdata->priv = priv = H5MM_xfree (priv);
		HRETURN_ERROR (H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
			       "unable to convert member data type");
	    }
	    priv->memb_conv[src2dst[i]] = tconv_func;
	}
    }

    cdata->need_bkg = H5T_BKG_TEMP;
    cdata->recalc = FALSE;
    FUNC_LEAVE (SUCCEED);
}

/*-------------------------------------------------------------------------
 * Function:	H5T_conv_struct
 *
 * Purpose:	Converts between compound data types.  This is a soft
 *		conversion function.  The algorithm is basically:
 *
 * 		For I=1..NUM_MEMBERS do
 *		  If sizeof detination type <= sizeof source type then
 *		    Convert member to destination type;
 *		  Move member as far left as possible;
 *		  
 *		For I=NUM_MEMBERS..1 do
 *		  If not destination type then
 *		    Convert member to destination type;
 *		  Move member to correct position in BACKGROUND
 *
 * 		Copy BACKGROUND to BUF
 *
 * Return:	Success:	SUCCEED
 *
 *		Failure:	FAIL
 *
 * Programmer:	Robb Matzke
 *              Thursday, January 22, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5T_conv_struct(hid_t src_id, hid_t dst_id, H5T_cdata_t *cdata, size_t nelmts,
		void *_buf, void *_bkg)
{
    uint8	*buf = (uint8 *)_buf;	/*cast for pointer arithmetic	*/
    uint8	*bkg = (uint8 *)_bkg;	/*background pointer arithmetic	*/
    H5T_t	*src = NULL;		/*source data type		*/
    H5T_t	*dst = NULL;		/*destination data type		*/
    intn	*src2dst = NULL;	/*maps src member to dst member	*/
    H5T_member_t *src_memb = NULL;	/*source struct member descript.*/
    H5T_member_t *dst_memb = NULL;	/*destination struct memb desc.	*/
    size_t	offset;			/*byte offset wrt struct	*/
    size_t	src_delta, dst_delta;	/*source & destination stride	*/
    intn	elmtno, i;		/*counters			*/
    H5T_conv_struct_t *priv = (H5T_conv_struct_t *)(cdata->priv);

    FUNC_ENTER (H5T_conv_struct, FAIL);

    switch (cdata->command) {
    case H5T_CONV_INIT:
	/*
	 * First, determine if this conversion function applies to the
	 * conversion path SRC_ID-->DST_ID.  If not, return failure;
	 * otherwise initialize the `priv' field of `cdata' with information
	 * that remains (almost) constant for this conversion path.
	 */
	if (H5_DATATYPE != H5I_group(src_id) ||
	    NULL == (src = H5I_object(src_id)) ||
	    H5_DATATYPE != H5I_group(dst_id) ||
	    NULL == (dst = H5I_object(dst_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a data type");
	}
	assert (H5T_COMPOUND==src->type);
	assert (H5T_COMPOUND==dst->type);

#ifndef LATER
	/*
	 * Struct members must be scalar for now.
	 */
	for (i=0; i<src->u.compnd.nmembs; i++) {
	    if (src->u.compnd.memb[i].ndims>0) {
		HRETURN_ERROR (H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
			       "array members are not supported yet");
	    }
	}
	for (i=0; i<dst->u.compnd.nmembs; i++) {
	    if (dst->u.compnd.memb[i].ndims>0) {
		HRETURN_ERROR (H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
			       "array members are not supported yet");
	    }
	}
#endif

	if (H5T_conv_struct_init (src, dst, cdata)<0) {
	    HRETURN_ERROR (H5E_DATATYPE, H5E_CANTINIT, FAIL,
			   "unable to initialize conversion data");
	}
	break;

    case H5T_CONV_FREE:
	/*
	 * Free the private conversion data.
	 */
#ifdef H5T_DEBUG
	if (cdata->ncalls>0) {
	    fprintf (stderr, "H5T: H5T_conv_struct statistics...\n");
	    fprintf (stderr, "   Number of calls:       %lu\n", cdata->ncalls);
	    fprintf (stderr, "   Data points converted: %lu\n", cdata->nelmts);
	}
#endif
	H5MM_xfree (priv->src2dst);
	H5MM_xfree (priv->src_memb_id);
	H5MM_xfree (priv->dst_memb_id);
	H5MM_xfree (priv->memb_conv);
	cdata->priv = priv = H5MM_xfree (priv);
	break;

    case H5T_CONV_CONV:
	/*
	 * Conversion.
	 */
	if (H5_DATATYPE != H5I_group(src_id) ||
	    NULL == (src = H5I_object(src_id)) ||
	    H5_DATATYPE != H5I_group(dst_id) ||
	    NULL == (dst = H5I_object(dst_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a data type");
	}
	assert (priv);
	assert (bkg && cdata->need_bkg>=H5T_BKG_TEMP);

	if (cdata->recalc &&
	    H5T_conv_struct_init (src, dst, cdata)<0) {
	    HRETURN_ERROR (H5E_DATATYPE, H5E_CANTINIT, FAIL,
			   "unable to initialize conversion data");
	}

	/*
	 * Insure that members are sorted.
	 */
	H5T_sort_by_offset (src);
	H5T_sort_by_offset (dst);
	src2dst = priv->src2dst;

	/*
	 * Direction of conversion.
	 */
	if (dst->size <= src->size) {
	    src_delta = src->size;
	    dst_delta = dst->size;
	} else {
	    src_delta = -(src->size);
	    dst_delta = -(dst->size);
	    buf += (nelmts-1) * src->size;
	    bkg += (nelmts-1) * dst->size;
	}

	for (elmtno=0; elmtno<nelmts; elmtno++) {
	    /*
	     * For each source member which will be present in the
	     * destination, convert the member to the destination type unless
	     * it is larger than the source type.  Then move the member to the
	     * left-most unoccupied position in the buffer.  This makes the
	     * data point as small as possible with all the free space on the
	     * right side.
	     */
	    for (i=0, offset=0; i<src->u.compnd.nmembs; i++) {
		if (src2dst[i]<0) continue;
		src_memb = src->u.compnd.memb + i;
		dst_memb = dst->u.compnd.memb + src2dst[i];

		if (H5T_get_size (dst_memb->type) <=
		    H5T_get_size (src_memb->type)) {
		    H5T_conv_t tconv_func = priv->memb_conv[src2dst[i]];
		    H5T_cdata_t *memb_cdata = priv->memb_cdata[src2dst[i]];
		    memb_cdata->command = H5T_CONV_CONV;
		    (tconv_func)(priv->src_memb_id[src2dst[i]],
				 priv->dst_memb_id[src2dst[i]],
				 memb_cdata,
				 1,
				 buf + src_memb->offset,
				 bkg + dst_memb->offset);

		    HDmemmove (buf + offset, buf + src_memb->offset,
			       H5T_get_size (dst_memb->type));
		    offset += H5T_get_size (dst_memb->type);
		} else {
		    HDmemmove (buf + offset, buf + src_memb->offset,
			       H5T_get_size (src_memb->type));
		    offset += H5T_get_size (src_memb->type);
		}
	    }

	    /*
	     * For each source member which will be present in the
	     * destination, convert the member to the destination type if it
	     * is larger than the source type (that is, has not been converted
	     * yet).  Then copy the member to the destination offset in the
	     * background buffer.
	     */
	    for (i=src->u.compnd.nmembs-1; i>=0; --i) {
		if (src2dst[i]<0) continue;
		src_memb = src->u.compnd.memb + i;
		dst_memb = dst->u.compnd.memb + src2dst[i];
		offset -= H5T_get_size (dst_memb->type);

		if (H5T_get_size (dst_memb->type) >
		    H5T_get_size (src_memb->type)) {
		    H5T_conv_t tconv_func = priv->memb_conv[src2dst[i]];
		    H5T_cdata_t *memb_cdata = priv->memb_cdata[src2dst[i]];
		    memb_cdata->command = H5T_CONV_CONV;
		    (tconv_func)(priv->src_memb_id[src2dst[i]],
				 priv->dst_memb_id[src2dst[i]], memb_cdata, 1,
				 buf + offset, bkg + dst_memb->offset);
		}
		HDmemmove (bkg+dst_memb->offset, buf+offset,
			   H5T_get_size (dst_memb->type));
	    }
	    assert (0==offset);

	    /*
	     * Update buf and background.
	     */
	    buf += src_delta;
	    bkg += dst_delta;
	}

	/*
	 * Copy the background buffer back into the in-place conversion
	 * buffer.
	 */
	HDmemcpy (_buf, _bkg, nelmts*dst->size);
	break;

    default:
	/* Some other command we don't know about yet.*/
	HRETURN_ERROR (H5E_DATATYPE, H5E_UNSUPPORTED, FAIL,
		       "unknown conversion command");
    }
    
    FUNC_LEAVE (SUCCEED);
}