/*
 * Copyright (c) 2001-2002 Michael David Adams.
 * All rights reserved.
 */

/* __START_OF_JASPER_LICENSE__
 *
 * JasPer License Version 2.0
 *
 * Copyright (c) 2001-2006 Michael David Adams
 * Copyright (c) 1999-2000 Image Power, Inc.
 * Copyright (c) 1999-2000 The University of British Columbia
 *
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person (the
 * "User") obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, and/or sell copies of the Software, and to permit
 * persons to whom the Software is furnished to do so, subject to the
 * following conditions:
 *
 * 1.  The above copyright notices and this permission notice (which
 * includes the disclaimer below) shall be included in all copies or
 * substantial portions of the Software.
 *
 * 2.  The name of a copyright holder shall not be used to endorse or
 * promote products derived from the Software without specific prior
 * written permission.
 *
 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
 * LICENSE.  NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
 * THIS DISCLAIMER.  THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
 * "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.  IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  NO ASSURANCES ARE
 * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE
 * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY.
 * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS
 * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL
 * PROPERTY RIGHTS OR OTHERWISE.  AS A CONDITION TO EXERCISING THE RIGHTS
 * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE
 * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY.  THE SOFTWARE
 * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
 * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
 * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
 * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH
 * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
 * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
 * RISK ACTIVITIES").  THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY
 * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
 *
 * __END_OF_JASPER_LICENSE__
 */

/*
 * Tag-Value Parser Library
 *
 * $Id$
 */

/******************************************************************************\
* Includes.
\******************************************************************************/

#include <assert.h>
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

#include "jasper/jas_malloc.h"
#include "jasper/jas_string.h"
#include "jasper/jas_tvp.h"

/******************************************************************************\
* Macros.
\******************************************************************************/

/* Is the specified character valid for a tag name? */
#define JAS_TVP_ISTAG(x) \
    (isalpha(x) || (x) == '_' || isdigit(x))

/******************************************************************************\
* Code for creating and destroying a tag-value parser.
\******************************************************************************/

jas_tvparser_t *jas_tvparser_create(const char *s)
{
    jas_tvparser_t *tvp;
    if (!(tvp = jas_malloc(sizeof(jas_tvparser_t)))) {
        return 0;
    }
    if (!(tvp->buf = jas_strdup(s))) {
        jas_tvparser_destroy(tvp);
        return 0;
    }
    tvp->pos = tvp->buf;
    tvp->tag = 0;
    tvp->val = 0;
    return tvp;
}

void jas_tvparser_destroy(jas_tvparser_t *tvp)
{
    if (tvp->buf) {
        jas_free(tvp->buf);
    }
    jas_free(tvp);
}

/******************************************************************************\
* Main parsing code.
\******************************************************************************/

/* Get the next tag-value pair. */
int jas_tvparser_next(jas_tvparser_t *tvp)
{
    char *p;
    char *tag;
    char *val;

    /* Skip any leading whitespace. */
    p = tvp->pos;
    while (*p != '\0' && isspace(*p)) {
        ++p;
    }

    /* Has the end of the input data been reached? */
    if (*p == '\0') {
        /* No more tags are present. */
        tvp->pos = p;
        return 1;
    }

    /* Does the tag name begin with a valid character? */
    if (!JAS_TVP_ISTAG(*p)) {
        return -1;
    }

    /* Remember where the tag name begins. */
    tag = p;

    /* Find the end of the tag name. */
    while (*p != '\0' && JAS_TVP_ISTAG(*p)) {
        ++p;
    }

    /* Has the end of the input data been reached? */
    if (*p == '\0') {
        /* The value field is empty. */
        tvp->tag = tag;
        tvp->val = "";
        tvp->pos = p;
        return 0;
    }

    /* Is a value field not present? */
    if (*p != '=') {
        if (*p != '\0' && !isspace(*p)) {
            return -1;
        }
        *p++ = '\0';
        tvp->tag = tag;
        tvp->val = "";
        tvp->pos = p;
        return 0;
    }

    *p++ = '\0';

    val = p;
    while (*p != '\0' && !isspace(*p)) {
        ++p;
    }

    if (*p != '\0') {
        *p++ = '\0';
    }

    tvp->pos = p;
    tvp->tag = tag;
    tvp->val = val;

    return 0;
}

/******************************************************************************\
* Code for querying the current tag/value.
\******************************************************************************/

/* Get the current tag. */
char *jas_tvparser_gettag(jas_tvparser_t *tvp)
{
    return tvp->tag;
}

/* Get the current value. */
char *jas_tvparser_getval(jas_tvparser_t *tvp)
{
    return tvp->val;
}

/******************************************************************************\
* Miscellaneous code.
\******************************************************************************/

/* Lookup a tag by name. */
jas_taginfo_t *jas_taginfos_lookup(jas_taginfo_t *taginfos, const char *name)
{
    jas_taginfo_t *taginfo;
    taginfo = taginfos;
    while (taginfo->id >= 0) {
        if (!strcmp(taginfo->name, name)) {
            return taginfo;
        }
        ++taginfo;
    }
    return 0;
}

/* This function is simply for convenience. */
/* One can avoid testing for the special case of a null pointer, by
  using this function.   This function never returns a null pointer.  */
jas_taginfo_t *jas_taginfo_nonull(jas_taginfo_t *taginfo)
{
    static jas_taginfo_t invalidtaginfo = {
        -1, 0
    };

    return taginfo ? taginfo : &invalidtaginfo;
}
