/*
 * Copyright (C) 1998 NCSA
 *		      All rights reserved.
 *
 * Programmer:	Robb Matzke <matzke@llnl.gov>
 *		Wednesday, April  1, 1998
 *
 * Purpose:	Functions that operate on a shared message.  The shared
 *		message doesn't ever actually appear in the object header as
 *		a normal message.  Instead, if a message is shared, the
 *		H5O_FLAG_SHARED bit is set and the message body is that
 *		defined here for H5O_SHARED.  The message ID is the ID of the
 *		pointed-to message and the pointed-to message is stored in
 *		the global heap.
 */
#include <H5private.h>
#include <H5Eprivate.h>
#include <H5MMprivate.h>
#include <H5Oprivate.h>

static void *H5O_shared_decode (H5F_t*, const uint8*, H5O_shared_t *sh);
static herr_t H5O_shared_encode (H5F_t*, uint8*, const void*);
static size_t H5O_shared_size (H5F_t*, const void*);
static herr_t H5O_shared_debug (H5F_t*, const void*, FILE*, intn, intn);

/* This message derives from H5O */
const H5O_class_t H5O_SHARED[1] = {{
    H5O_SHARED_ID,	    	/*message id number			*/
    "shared",		    	/*message name for debugging		*/
    sizeof(H5O_shared_t), 	/*native message size			*/
    H5O_shared_decode,	    	/*decode method				*/
    H5O_shared_encode,	    	/*encode method				*/
    NULL,		    	/*no copy method			*/
    H5O_shared_size,	    	/*size method				*/
    NULL,		    	/*no reset method			*/
    NULL,			/*get share method			*/
    NULL, 			/*set share method			*/
    H5O_shared_debug,	    	/*debug method				*/
}};

#define H5O_SHARED_VERSION	1

/* Interface initialization */
#define PABLO_MASK	H5O_shared_mask
static hbool_t interface_initialize_g = FALSE;
#define INTERFACE_INIT  NULL


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_decode
 *
 * Purpose:	Decodes a shared object message and returns it.
 *
 * Return:	Success:	Ptr to a new shared object message.
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *              Thursday, April  2, 1998
 *
 * Modifications:
 *	Robb Matzke, 1998-07-20
 *	Added a version number to the beginning of the message.
 *-------------------------------------------------------------------------
 */
static void *
H5O_shared_decode (H5F_t *f, const uint8 *buf, H5O_shared_t __unused__ *sh)
{
    H5O_shared_t	*mesg;
    uintn		flags, version;
    
    FUNC_ENTER (H5O_shared_decode, NULL);

    /* Check args */
    assert (f);
    assert (buf);
    assert (!sh);

    /* Decode */
    if (NULL==(mesg = H5MM_calloc (sizeof *mesg))) {
	HRETURN_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
		       "memory allocation failed");
    }

    /* Version */
    version = *buf++;
    if (version!=H5O_SHARED_VERSION) {
	HRETURN_ERROR(H5E_OHDR, H5E_CANTLOAD, NULL,
		      "bad version number for shared object message");
    }

    /* Flags */
    flags = *buf++;
    mesg->in_gh = (flags & 0x01);

    /* Reserved */
    buf += 6;

    /* Body */
    if (mesg->in_gh) {
	H5F_addr_decode (f, &buf, &(mesg->u.gh.addr));
	INT32DECODE (buf, mesg->u.gh.idx);
    } else {
	H5G_ent_decode (f, &buf, &(mesg->u.ent));
    }

    FUNC_LEAVE (mesg);
}


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_encode
 *
 * Purpose:	Encodes message _MESG into buffer BUF.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Thursday, April  2, 1998
 *
 * Modifications:
 *	Robb Matzke, 1998-07-20
 *	Added a version number to the beginning of the message.
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_shared_encode (H5F_t *f, uint8 *buf/*out*/, const void *_mesg)
{
    const H5O_shared_t	*mesg = (const H5O_shared_t *)_mesg;
    uintn		flags;
    
    FUNC_ENTER (H5O_shared_encode, FAIL);

    /* Check args */
    assert (f);
    assert (buf);
    assert (mesg);

    /* Encode */
    *buf++ = H5O_SHARED_VERSION;
    flags = mesg->in_gh ? 0x01 : 0x00;
    *buf++ = flags;
    *buf++ = 0; /*reserved 1*/
    *buf++ = 0; /*reserved 2*/
    *buf++ = 0; /*reserved 3*/
    *buf++ = 0; /*reserved 4*/
    *buf++ = 0; /*reserved 5*/
    *buf++ = 0; /*reserved 6*/

    if (mesg->in_gh) {
	H5F_addr_encode (f, &buf, &(mesg->u.gh.addr));
	INT32ENCODE (buf, mesg->u.gh.idx);
    } else {
	H5G_ent_encode (f, &buf, &(mesg->u.ent));
    }

    FUNC_LEAVE (SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_size
 *
 * Purpose:	Returns the length of a shared object message.
 *
 * Return:	Success:	Length
 *
 *		Failure:	0
 *
 * Programmer:	Robb Matzke
 *              Thursday, April  2, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static size_t
H5O_shared_size (H5F_t *f, const void __unused__ *_mesg)
{
    size_t	size;
    
    FUNC_ENTER (H5O_shared_size, 0);

    size = 1 +				/*the flags field		*/
	   7 +				/*reserved			*/
	   MAX (H5F_SIZEOF_ADDR(f)+4,	/*sharing via global heap	*/
		H5G_SIZEOF_ENTRY(f));	/*sharing by another obj hdr	*/

    FUNC_LEAVE (size);
}


/*-------------------------------------------------------------------------
 * Function:	H5O_shared_debug
 *
 * Purpose:	Prints debugging info for the message
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Thursday, April  2, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5O_shared_debug (H5F_t __unused__ *f, const void *_mesg,
		  FILE *stream, intn indent, intn fwidth)
{
    const H5O_shared_t	*mesg = (const H5O_shared_t *)_mesg;

    FUNC_ENTER (H5O_shared_debug, FAIL);

    /* Check args */
    assert (f);
    assert (mesg);
    assert (stream);
    assert (indent>=0);
    assert (fwidth>=0);

    if (mesg->in_gh) {
	HDfprintf (stream, "%*s%-*s %s\n", indent, "", fwidth,
		   "Sharing method",
		   "Global heap");
	HDfprintf (stream, "%*s%-*s %a\n", indent, "", fwidth,
		 "Collection address:",
		   &(mesg->u.gh.addr));
	HDfprintf (stream, "%*s%-*s %d\n", indent, "", fwidth,
		   "Object ID within collection:",
		   mesg->u.gh.idx);
    } else {
	HDfprintf (stream, "%*s%-*s %s\n", indent, "", fwidth,
		   "Sharing method",
		   "Obj Hdr");
	H5G_ent_debug (f, &(mesg->u.ent), stream, indent, fwidth, NULL);
    }
    
    FUNC_LEAVE (SUCCEED);
}
