/*
   XDS - OSSP Extensible Data Serialization Library
   Copyright (c) 2001 The OSSP Project (http://www.ossp.org/)
   Copyright (c) 2001 Cable & Wireless Deutschland (http://www.cw.com/de/)

   This file is part of OSSP XDS, an extensible data serialization
   library which can be found at http://www.ossp.com/pkg/xds/.

   Permission to use, copy, modify, and distribute this software for
   any purpose with or without fee is hereby granted, provided that
   the above copyright notice and this permission notice appear in all
   copies.

   THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   SUCH DAMAGE.
*/

#include <string.h>
#include <ctype.h>
#include "internal.h"

int xds_vdecode(xds_t* xds, const char* fmt_arg, va_list args)
    {
    size_t buffer_len_backup;
    char* name;
    char* p;
    char* fmt;
    int rc;

    /* Sanity checks. */

    xds_check_parameter(xds != NULL);
    xds_check_parameter(fmt_arg != NULL);
    assert(xds->mode == XDS_DECODE);
    if (xds->mode != XDS_DECODE)
	return XDS_ERR_INVALID_MODE;

    /* Ensure we have a buffer to decode. */

    if (xds->buffer == NULL || xds->buffer_capacity == 0)
	return XDS_ERR_UNDERFLOW;

    /* Iterate through the items in the format string and execute the
       apropriate engines. */

    fmt = p = strdup(fmt_arg);
    if (fmt == NULL)
	return XDS_ERR_NO_MEM;
    buffer_len_backup = xds->buffer_len;
    for(name = p; *p != '\0'; name = p)
	{
	while(isalnum((int)*p) || *p == '-' || *p == '_')
	    ++p;
	if (*p)
	    *p++ = '\0';
	else
	    *p = '\0';

	if (strlen(name) > 0)
	    {
	    size_t pos;
	    size_t used_buffer_size = 0;
	    if (xds_find_engine(xds->engines, xds->engines_len, name, &pos))
		{
		rc = (*xds->engines[pos].engine)(xds,
						 xds->engines[pos].context,
						 xds->buffer + xds->buffer_len,
						 xds->buffer_capacity - xds->buffer_len,
						 &used_buffer_size,
						 &args);
		assert(rc <= 0);
		if (rc == XDS_OK)
		    xds->buffer_len += used_buffer_size;
		else
		    goto leave;
		}
	    else
		{
		rc = XDS_ERR_UNKNOWN_ENGINE;
		goto leave;
		}
	    }
	}
    rc = XDS_OK;

    /* Clean up and leave. */
  leave:
    free(fmt);
    if (rc != XDS_OK)
	xds->buffer_len = buffer_len_backup;
    return rc;
    }