path: root/libical/src/libical/icalvalue.c

/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vi:set ts=4 sts=4 sw=4 expandtab : */
/*======================================================================
  FILE: icalvalue.c
  CREATOR: eric 02 May 1999
  
  $Id$


 (C) COPYRIGHT 2000, Eric Busboom, http://www.softwarestudio.org

 This program is free software; you can redistribute it and/or modify
 it under the terms of either: 

    The LGPL as published by the Free Software Foundation, version
    2.1, available at: http://www.fsf.org/copyleft/lesser.html

  Or:

    The Mozilla Public License Version 1.0. You may obtain a copy of
    the License at http://www.mozilla.org/MPL/

  The original code is icalvalue.c

  Contributions from:
     Graham Davison (g.m.davison@computer.org)


======================================================================*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "icalerror.h"
#include "icalmemory.h"
#include "icalparser.h"
#include "icalenums.h"
#include "icalvalueimpl.h"

#include <stdlib.h> /* for malloc */
#include <stdio.h> /* for sprintf */
#include <string.h> /* For memset, others */
#include <stddef.h> /* For offsetof() macro */
#include <errno.h>
#include <time.h> /* for mktime */
#include <stdlib.h> /* for atoi and atof */
#include <limits.h> /* for SHRT_MAX */         

#ifdef WIN32
#define snprintf      _snprintf
#define strcasecmp    stricmp
#endif

#if _MAC_OS_
#include "icalmemory_strdup.h"
#endif

#define TMP_BUF_SIZE 1024

void print_datetime_to_string(char* str,  const struct icaltimetype *data);
void print_date_to_string(char* str,  const struct icaltimetype *data);
void print_time_to_string(char* str,  const struct icaltimetype *data);


struct icalvalue_impl*  icalvalue_new_impl(icalvalue_kind kind){

    struct icalvalue_impl* v;

    if (!icalvalue_kind_is_valid(kind))
      return NULL;

    if ( ( v = (struct icalvalue_impl*)
       malloc(sizeof(struct icalvalue_impl))) == 0) {
    icalerror_set_errno(ICAL_NEWFAILED_ERROR);
    return 0;
    }
    
    strcpy(v->id,"val");
    
    v->kind = kind;
    v->size = 0;
    v->parent = 0;
    v->x_value = 0;
    memset(&(v->data),0,sizeof(v->data));
    
    return v;

}



icalvalue*
icalvalue_new (icalvalue_kind kind)
{
    return (icalvalue*)icalvalue_new_impl(kind);
}

icalvalue* icalvalue_new_clone(const icalvalue* old) {
    struct icalvalue_impl* new;

    new = icalvalue_new_impl(old->kind);

    if (new == 0){
    return 0;
    }

    strcpy(new->id, old->id);
    new->kind = old->kind;
    new->size = old->size;

    switch (new->kind){
    case ICAL_ATTACH_VALUE: 
    case ICAL_BINARY_VALUE: 
    {
        /* Hmm.  We just ref the attach value, which may not be the right
         * thing to do.  We cannot quite copy the data, anyways, since we
         * don't know how long it is.
         */
        new->data.v_attach = old->data.v_attach;
        if (new->data.v_attach)
        icalattach_ref (new->data.v_attach);

        break;
    }
    case ICAL_QUERY_VALUE:
    case ICAL_STRING_VALUE:
    case ICAL_TEXT_VALUE:
    case ICAL_CALADDRESS_VALUE:
    case ICAL_URI_VALUE:
    {
        if (old->data.v_string != 0) { 
        new->data.v_string=icalmemory_strdup(old->data.v_string);

        if ( new->data.v_string == 0 ) {
            return 0;
        }           

        }
        break;
    }
    case ICAL_RECUR_VALUE:
    {
        if(old->data.v_recur != 0){
        new->data.v_recur = malloc(sizeof(struct icalrecurrencetype));

        if(new->data.v_recur == 0){
            return 0;
        }

        memcpy( new->data.v_recur, old->data.v_recur,
            sizeof(struct icalrecurrencetype)); 
        }
        break;
    }

    case ICAL_X_VALUE: 
    {
        if (old->x_value != 0) {
        new->x_value=icalmemory_strdup(old->x_value);

        if (new->x_value == 0) {
            return 0;
        }
        }

        break;
    }

    default:
    {
        /* all of the other types are stored as values, not
               pointers, so we can just copy the whole structure. */

        new->data = old->data;
    }
    }

    return new;
}

static char* icalmemory_strdup_and_dequote(const char* str)
{
    const char* p;
    char* out = (char*)malloc(sizeof(char) * strlen(str) +1);
    char* pout;

    if (out == 0){
    return 0;
    }

    pout = out;

    for (p = str; *p!=0; p++){
    
    if( *p == '\\')
    {
        p++;
        switch(*p){
        case 0:
        {
            *pout = '\0';
            break;

        }
        case 'n':
        case 'N':
        {
            *pout = '\n';
            break;
        }
        case 't':
        case 'T':
        {
            *pout = '\t';
            break;
        }
        case 'r':
        case 'R':
        {
            *pout = '\r';
            break;
        }
        case 'b':
        case 'B':
        {
            *pout = '\b';
            break;
        }
        case 'f':
        case 'F':
        {
            *pout = '\f';
            break;
        }
        case ';':
        case ',':
        case '"':
        case '\\':
        {
            *pout = *p;
            break;
        }
        default:
        {
            *pout = ' ';
        }       
        }
    } else {
        *pout = *p;
    }

    pout++;
    
    }

    *pout = '\0';

    return out;
}

/*
 * FIXME
 *
 * This is a bad API, as it forces callers to specify their own X type.
 * This function should take care of this by itself.
 */
static
icalvalue* icalvalue_new_enum(icalvalue_kind kind, int x_type, const char* str)
{
    int e = icalproperty_kind_and_string_to_enum(kind, str);
    struct icalvalue_impl *value; 

    if(e != 0 && icalproperty_enum_belongs_to_property(
                   icalproperty_value_kind_to_kind(kind),e)) {
        
        value = icalvalue_new_impl(kind);
        value->data.v_enum = e;
    } else {
        /* Make it an X value */
        value = icalvalue_new_impl(kind);
        value->data.v_enum = x_type;
        icalvalue_set_x(value,str);
    }

    return value;
}


icalvalue* icalvalue_new_from_string_with_error(icalvalue_kind kind,const char* str,icalproperty** error)
{

    struct icalvalue_impl *value = 0;
    
    icalerror_check_arg_rz(str!=0,"str");

    if (error != 0){
    *error = 0;
    }

    switch (kind){
    
    case ICAL_ATTACH_VALUE:
    {
        icalattach *attach;

        attach = icalattach_new_from_url (str);
        if (!attach)
        break;

        value = icalvalue_new_attach (attach);
        icalattach_unref (attach);
        break;
    }

    case ICAL_BINARY_VALUE:
    case ICAL_BOOLEAN_VALUE:
        {
            /* HACK */
            value = 0;
            
        if (error != 0){
        char temp[TMP_BUF_SIZE];
        sprintf(temp,"%s Values are not implemented",
                        icalvalue_kind_to_string(kind)); 
        *error = icalproperty_vanew_xlicerror( 
                                   temp, 
                                   icalparameter_new_xlicerrortype( 
                                        ICAL_XLICERRORTYPE_VALUEPARSEERROR), 
                                   0); 
        }
        break;
    }
        

    case ICAL_TRANSP_VALUE:
        value = icalvalue_new_enum(kind, (int)ICAL_TRANSP_X,str);
        break;
    case ICAL_METHOD_VALUE:
        value = icalvalue_new_enum(kind, (int)ICAL_METHOD_X,str);
        break;
    case ICAL_STATUS_VALUE:
        value = icalvalue_new_enum(kind, (int)ICAL_STATUS_X,str);
        break;
    case ICAL_ACTION_VALUE:
        value = icalvalue_new_enum(kind, (int)ICAL_ACTION_X,str);
        break;

    case ICAL_QUERY_VALUE:
        value = icalvalue_new_query(str);
        break;

    case ICAL_CLASS_VALUE:
        value = icalvalue_new_enum(kind, (int)ICAL_CLASS_X,str);
        break;

    case ICAL_CMD_VALUE:
        value = icalvalue_new_enum(kind, ICAL_CMD_X,str);
        break;
    case ICAL_QUERYLEVEL_VALUE:
        value = icalvalue_new_enum(kind, ICAL_QUERYLEVEL_X,str);
        break;
    case ICAL_CARLEVEL_VALUE:
        value = icalvalue_new_enum(kind, ICAL_CARLEVEL_X,str);
        break;


    case ICAL_INTEGER_VALUE:
        value = icalvalue_new_integer(atoi(str));
        break;

    case ICAL_FLOAT_VALUE:
        value = icalvalue_new_float((float)atof(str));
        break;

    case ICAL_UTCOFFSET_VALUE:
    {
            int t,utcoffset, hours, minutes, seconds;
            /* treat the UTCOFSET string a a decimal number, disassemble its digits
               and reconstruct it as sections */
            t = strtol(str,0,10);
            /* add phantom seconds field */
            if(abs(t)<9999){t *= 100; }
            hours = (t/10000);
            minutes = (t-hours*10000)/100;
            seconds = (t-hours*10000-minutes*100);
            utcoffset = hours*3600+minutes*60+seconds;

        value = icalvalue_new_utcoffset(utcoffset);

        break;
    }
        
    case ICAL_TEXT_VALUE:
    {
        char* dequoted_str = icalmemory_strdup_and_dequote(str);
        value = icalvalue_new_text(dequoted_str);
        free(dequoted_str);
        break;
    }
        
    case ICAL_STRING_VALUE:
        value = icalvalue_new_string(str);
        break;
        
    case ICAL_CALADDRESS_VALUE:
        value = icalvalue_new_caladdress(str);
        break;
        
    case ICAL_URI_VALUE:
        value = icalvalue_new_uri(str);
        break;
        
    case ICAL_GEO_VALUE:
        value = 0;
        /* HACK */
            
        if (error != 0){
        char temp[TMP_BUF_SIZE];
        sprintf(temp,"GEO Values are not implemented"); 
        *error = icalproperty_vanew_xlicerror( 
            temp, 
            icalparameter_new_xlicerrortype( 
            ICAL_XLICERRORTYPE_VALUEPARSEERROR), 
            0); 
        }

        /*icalerror_warn("Parsing GEO properties is unimplmeneted");*/

        break;
        
    case ICAL_RECUR_VALUE:
    {
        struct icalrecurrencetype rt;
        rt = icalrecurrencetype_from_string(str);
            if(rt.freq != ICAL_NO_RECURRENCE){
                value = icalvalue_new_recur(rt);
            }
        break;
    }
        
    case ICAL_DATE_VALUE:
    case ICAL_DATETIME_VALUE:
    {
        struct icaltimetype tt;
      
        tt = icaltime_from_string(str);
            if(!icaltime_is_null_time(tt)){
                value = icalvalue_new_impl(kind);
                value->data.v_time = tt;

                icalvalue_reset_kind(value);
            }
        break;
    }
        
    case ICAL_DATETIMEPERIOD_VALUE:
    {
        struct icaltimetype tt;
            struct icalperiodtype p;
            tt = icaltime_from_string(str);

            if(!icaltime_is_null_time(tt)){
                value = icalvalue_new_datetime(tt);     
        break;
            }  
        
            p = icalperiodtype_from_string(str);        
        if (!icalperiodtype_is_null_period(p)){
                value = icalvalue_new_period(p);
            }            

            break;
    }
        
    case ICAL_DURATION_VALUE:
    {
            struct icaldurationtype dur = icaldurationtype_from_string(str);
            
            if (!icaldurationtype_is_bad_duration(dur)) {    /* failed to parse */
                value = icalvalue_new_duration(dur);
            }
            
        break;
    }
        
    case ICAL_PERIOD_VALUE:
    {
            struct icalperiodtype p;
            p = icalperiodtype_from_string(str);  
            
            if(!icalperiodtype_is_null_period(p)){
                value = icalvalue_new_period(p);
            }
            break; 
    }
    
    case ICAL_TRIGGER_VALUE:
    {
        struct icaltriggertype tr = icaltriggertype_from_string(str);
            if (!icaltriggertype_is_bad_trigger(tr)) {
                value = icalvalue_new_trigger(tr);
            }
        break;
    }
        
    case ICAL_REQUESTSTATUS_VALUE:
        {
            struct icalreqstattype rst = icalreqstattype_from_string(str);
            if(rst.code != ICAL_UNKNOWN_STATUS){
                value = icalvalue_new_requeststatus(rst);
            }
            break;

        }

    case ICAL_X_VALUE:
        {
            char* dequoted_str = icalmemory_strdup_and_dequote(str);
            value = icalvalue_new_x(dequoted_str);
            free(dequoted_str);
        }
        break;

    default:
        {
            if (error != 0 ){
        char temp[TMP_BUF_SIZE];
                
                snprintf(temp,TMP_BUF_SIZE,"Unknown type for \'%s\'",str);
                
        *error = icalproperty_vanew_xlicerror( 
            temp, 
            icalparameter_new_xlicerrortype( 
            ICAL_XLICERRORTYPE_VALUEPARSEERROR), 
            0); 
        }

        icalerror_warn("icalvalue_new_from_string got an unknown value type");
            value=0;
    }
    }


    if (error != 0 && *error == 0 && value == 0){
    char temp[TMP_BUF_SIZE];
    
        snprintf(temp,TMP_BUF_SIZE,"Failed to parse value: \'%s\'",str);
    
    *error = icalproperty_vanew_xlicerror( 
        temp, 
        icalparameter_new_xlicerrortype( 
        ICAL_XLICERRORTYPE_VALUEPARSEERROR), 
        0); 
    }


    return value;

}

icalvalue* icalvalue_new_from_string(icalvalue_kind kind,const char* str)
{
    return icalvalue_new_from_string_with_error(kind,str,(icalproperty**)0);
}



void
icalvalue_free (icalvalue* v)
{
    icalerror_check_arg_rv((v != 0),"value");

#ifdef ICAL_FREE_ON_LIST_IS_ERROR
    icalerror_assert( (v->parent ==0),"This value is still attached to a property");
    
#else
    if(v->parent !=0){
    return;
    }
#endif

    if(v->x_value != 0){
        free(v->x_value);
    }

    switch (v->kind){
    case ICAL_BINARY_VALUE: 
    case ICAL_ATTACH_VALUE: {
        if (v->data.v_attach) {
        icalattach_unref (v->data.v_attach);
        v->data.v_attach = NULL;
        }

        break;
    }
    case ICAL_TEXT_VALUE:
    case ICAL_CALADDRESS_VALUE:
    case ICAL_URI_VALUE:
    case ICAL_QUERY_VALUE:
    {
        if (v->data.v_string != 0) { 
        free((void*)v->data.v_string);
        v->data.v_string = 0;
        }
        break;
    }
    case ICAL_RECUR_VALUE:
    {
        if(v->data.v_recur != 0){
        free((void*)v->data.v_recur);
        v->data.v_recur = 0;
        }
        break;
    }

    default:
    {
        /* Nothing to do */
    }
    }

    v->kind = ICAL_NO_VALUE;
    v->size = 0;
    v->parent = 0;
    memset(&(v->data),0,sizeof(v->data));
    v->id[0] = 'X';
    free(v);
}

int
icalvalue_is_valid (const icalvalue* value)
{
    if(value == 0){
    return 0;
    }
    
    return 1;
}

static char* icalvalue_binary_as_ical_string(const icalvalue* value) {

    const char* data;
    char* str;
    icalerror_check_arg_rz( (value!=0),"value");

    data = icalvalue_get_binary(value);

    str = (char*)icalmemory_tmp_buffer(60);
    sprintf(str,"icalvalue_binary_as_ical_string is not implemented yet");

    return str;
}


#define MAX_INT_DIGITS 12 /* Enough for 2^32 + sign*/ 
    
static char* icalvalue_int_as_ical_string(const icalvalue* value) {
    int data;
    char* str = (char*)icalmemory_tmp_buffer(MAX_INT_DIGITS); 

    icalerror_check_arg_rz( (value!=0),"value");

    data = icalvalue_get_integer(value);
    
    snprintf(str,MAX_INT_DIGITS,"%d",data);

    return str;
}

static char* icalvalue_utcoffset_as_ical_string(const icalvalue* value)
{    
    int data,h,m,s;
    char sign;
    char* str = (char*)icalmemory_tmp_buffer(9);

    icalerror_check_arg_rz( (value!=0),"value");

    data = icalvalue_get_utcoffset(value);

    if (abs(data) == data){
    sign = '+';
    } else {
    sign = '-';
    }

    h = data/3600;
    m = (data - (h*3600))/ 60;
    s = (data - (h*3600) - (m*60));

    if (s > 0)
    sprintf(str,"%c%02d%02d%02d",sign,abs(h),abs(m),abs(s));
    else
    sprintf(str,"%c%02d%02d",sign,abs(h),abs(m));

    return str;
}

static char* icalvalue_string_as_ical_string(const icalvalue* value) {

    const char* data;
    char* str = 0;
    icalerror_check_arg_rz( (value!=0),"value");
    data = value->data.v_string;

    str = (char*)icalmemory_tmp_buffer(strlen(data)+1);   

    strcpy(str,data);

    return str;
}


static char* icalvalue_recur_as_ical_string(const icalvalue* value) 
{
    struct icalrecurrencetype *recur = value->data.v_recur;

    return icalrecurrencetype_as_string(recur);
}

 /* @todo This is not RFC2445 compliant.
 * The RFC only allows:
 * TSAFE-CHAR = %x20-21 / %x23-2B / %x2D-39 / %x3C-5B / %x5D-7E / NON-US-ASCII
 * As such, \t\r\b\f are not allowed, not even escaped
 */

static char* icalvalue_text_as_ical_string(const icalvalue* value) {
    char *str;
    char *str_p;
    char *rtrn;
    const char *p;
    size_t buf_sz;

    buf_sz = strlen(value->data.v_string)+1;

    str_p = str = (char*)icalmemory_new_buffer(buf_sz);

    if (str_p == 0){
      return 0;
    }

    for(p=value->data.v_string; *p!=0; p++){

    switch(*p){
        case '\n': {
        icalmemory_append_string(&str,&str_p,&buf_sz,"\\n");
        break;
        }

        case '\t': {
        icalmemory_append_string(&str,&str_p,&buf_sz,"\\t");
        break;
        }
        case '\r': {
        icalmemory_append_string(&str,&str_p,&buf_sz,"\\r");
        break;
        }
        case '\b': {
        icalmemory_append_string(&str,&str_p,&buf_sz,"\\b");
        break;
        }
        case '\f': {
        icalmemory_append_string(&str,&str_p,&buf_sz,"\\f");
        break;
        }

        case ';':
        case ',':
        case '"':
        case '\\':{
        icalmemory_append_char(&str,&str_p,&buf_sz,'\\');
        icalmemory_append_char(&str,&str_p,&buf_sz,*p);
        break;
        }

        default: {
        icalmemory_append_char(&str,&str_p,&buf_sz,*p);
        }
    }
    }

    /* Assume the last character is not a '\0' and add one. We could
       check *str_p != 0, but that would be an uninitialized memory
       read. */


    icalmemory_append_char(&str,&str_p,&buf_sz,'\0');

    rtrn = icalmemory_tmp_copy(str);

    icalmemory_free_buffer(str);

    return rtrn;
}


static char* 
icalvalue_attach_as_ical_string(const icalvalue* value) 
{
    icalattach *a;
    char * str;

    icalerror_check_arg_rz( (value!=0),"value");

    a = icalvalue_get_attach(value);

    if (icalattach_get_is_url (a)) {
    const char *url;

    url = icalattach_get_url (a);
    str = icalmemory_tmp_buffer (strlen (url) + 1);
    strcpy (str, url);
    return str;
    } else
    return icalvalue_binary_as_ical_string (value);
}


static char* icalvalue_duration_as_ical_string(const icalvalue* value) {

    struct icaldurationtype data;

    icalerror_check_arg_rz( (value!=0),"value");
    data = icalvalue_get_duration(value);

    return icaldurationtype_as_ical_string(data);
}

void print_time_to_string(char* str, const struct icaltimetype *data)
{
    char temp[20];

    if (icaltime_is_utc(*data)){
    sprintf(temp,"%02d%02d%02dZ",data->hour,data->minute,data->second);
    } else {
    sprintf(temp,"%02d%02d%02d",data->hour,data->minute,data->second);
    }   

    strcat(str,temp);
}

 
void print_date_to_string(char* str,  const struct icaltimetype *data)
{
    char temp[20];

    sprintf(temp,"%04d%02d%02d",data->year,data->month,data->day);

    strcat(str,temp);
}

static char* icalvalue_date_as_ical_string(const icalvalue* value) {

    struct icaltimetype data;
    char* str;
    icalerror_check_arg_rz( (value!=0),"value");
    data = icalvalue_get_date(value);

    str = (char*)icalmemory_tmp_buffer(9);
 
    str[0] = 0;
    print_date_to_string(str,&data);
   
    return str;
}

void print_datetime_to_string(char* str,  const struct icaltimetype *data)
{
    print_date_to_string(str,data);
    strcat(str,"T");
    print_time_to_string(str,data);
}

static const char* icalvalue_datetime_as_ical_string(const icalvalue* value) {
    
    struct icaltimetype data;
    char* str;
    icalvalue_kind kind = icalvalue_isa(value);    

    icalerror_check_arg_rz( (value!=0),"value");


    if( !(kind == ICAL_DATE_VALUE || kind == ICAL_DATETIME_VALUE ))
    {
        icalerror_set_errno(ICAL_BADARG_ERROR);
        return 0;
    }

    data = icalvalue_get_datetime(value);

    str = (char*)icalmemory_tmp_buffer(20);
 
    str[0] = 0;

    print_datetime_to_string(str,&data);
   
    return str;

}

static char* icalvalue_float_as_ical_string(const icalvalue* value) {

    float data;
    char* str;
    icalerror_check_arg_rz( (value!=0),"value");
    data = icalvalue_get_float(value);

    str = (char*)icalmemory_tmp_buffer(15);

    sprintf(str,"%f",data);

    return str;
}

static char* icalvalue_geo_as_ical_string(const icalvalue* value) {

    struct icalgeotype data;
    char* str;
    icalerror_check_arg_rz( (value!=0),"value");

    data = icalvalue_get_geo(value);

    str = (char*)icalmemory_tmp_buffer(25);

    sprintf(str,"%f;%f",data.lat,data.lon);

    return str;
}

static const char* icalvalue_datetimeperiod_as_ical_string(const icalvalue* value) {
    struct icaldatetimeperiodtype dtp = icalvalue_get_datetimeperiod(value);

    icalerror_check_arg_rz( (value!=0),"value");

    if(!icaltime_is_null_time(dtp.time)){
    return icaltime_as_ical_string(dtp.time);
    } else {
    return icalperiodtype_as_ical_string(dtp.period);
    }
}

static const char* icalvalue_period_as_ical_string(const icalvalue* value) {
    struct icalperiodtype data;
    icalerror_check_arg_rz( (value!=0),"value");
    data = icalvalue_get_period(value);

    return icalperiodtype_as_ical_string(data);

}

static const char* icalvalue_trigger_as_ical_string(const icalvalue* value) {

    struct icaltriggertype data;

    icalerror_check_arg_rz( (value!=0),"value");
    data = icalvalue_get_trigger(value);

    if(!icaltime_is_null_time(data.time)){
    return icaltime_as_ical_string(data.time);
    } else {
    return icaldurationtype_as_ical_string(data.duration);
    }   

}

const char*
icalvalue_as_ical_string(const icalvalue* value)
{
    if(value == 0){
    return 0;
    }

    switch (value->kind){

    case ICAL_ATTACH_VALUE:
        return icalvalue_attach_as_ical_string(value);
        
    case ICAL_BINARY_VALUE:
        return icalvalue_binary_as_ical_string(value);
        
    case ICAL_BOOLEAN_VALUE:
    case ICAL_INTEGER_VALUE:
        return icalvalue_int_as_ical_string(value);                  
        
    case ICAL_UTCOFFSET_VALUE:
        return icalvalue_utcoffset_as_ical_string(value);                  
        
    case ICAL_TEXT_VALUE:
        return icalvalue_text_as_ical_string(value);
        
    case ICAL_QUERY_VALUE:
        return icalvalue_string_as_ical_string(value);
        
    case ICAL_STRING_VALUE:
    case ICAL_URI_VALUE:
    case ICAL_CALADDRESS_VALUE:
        return icalvalue_string_as_ical_string(value);
        
    case ICAL_DATE_VALUE:
        return icalvalue_date_as_ical_string(value);
    case ICAL_DATETIME_VALUE:
        return icalvalue_datetime_as_ical_string(value);
    case ICAL_DURATION_VALUE:
        return icalvalue_duration_as_ical_string(value);
        
    case ICAL_PERIOD_VALUE:
        return icalvalue_period_as_ical_string(value);
    case ICAL_DATETIMEPERIOD_VALUE:
        return icalvalue_datetimeperiod_as_ical_string(value);
        
    case ICAL_FLOAT_VALUE:
        return icalvalue_float_as_ical_string(value);
        
    case ICAL_GEO_VALUE:
        return icalvalue_geo_as_ical_string(value);
        
    case ICAL_RECUR_VALUE:
        return icalvalue_recur_as_ical_string(value);
        
    case ICAL_TRIGGER_VALUE:
        return icalvalue_trigger_as_ical_string(value);

    case ICAL_REQUESTSTATUS_VALUE:
        return icalreqstattype_as_string(value->data.v_requeststatus);
        
    case ICAL_ACTION_VALUE:
    case ICAL_CMD_VALUE:
    case ICAL_QUERYLEVEL_VALUE:
    case ICAL_CARLEVEL_VALUE:
    case ICAL_METHOD_VALUE:
    case ICAL_STATUS_VALUE:
    case ICAL_TRANSP_VALUE:
    case ICAL_CLASS_VALUE:
        if(value->x_value !=0){
            return icalmemory_tmp_copy(value->x_value);
        }

        return icalproperty_enum_to_string(value->data.v_enum);
        
    case ICAL_X_VALUE: 
    if (value->x_value != 0)
            return icalmemory_tmp_copy(value->x_value);

    /* FALLTHRU */

    case ICAL_NO_VALUE:
    default:
    {
        return 0;
    }
    }
}


icalvalue_kind
icalvalue_isa (const icalvalue* value)
{
    if(value == 0){
    return ICAL_NO_VALUE;
    }

    return value->kind;
}


int
icalvalue_isa_value (void* value)
{
    struct icalvalue_impl *impl = (struct icalvalue_impl *)value;

    icalerror_check_arg_rz( (value!=0), "value");

    if (strcmp(impl->id,"val") == 0) {
    return 1;
    } else {
    return 0;
    }
}


static int icalvalue_is_time(const icalvalue* a) {
    icalvalue_kind kind = icalvalue_isa(a);

    if(kind == ICAL_DATETIME_VALUE ||
       kind == ICAL_DATE_VALUE ){
    return 1;
    }

    return 0;

}

/*
 * In case of error, this function returns 0. This is partly bogus, as 0 is
 * not part of the returned enum.
 * FIXME We should probably add an error value to the enum.
 */
icalparameter_xliccomparetype
icalvalue_compare(const icalvalue* a, const icalvalue *b)
{

    icalerror_check_arg_rz( (a!=0), "a");
    icalerror_check_arg_rz( (b!=0), "b");

    /* Not the same type; they can only be unequal */
    if( ! (icalvalue_is_time(a) && icalvalue_is_time(b)) &&
    icalvalue_isa(a) != icalvalue_isa(b)){
    return ICAL_XLICCOMPARETYPE_NOTEQUAL;
    }

    switch (icalvalue_isa(a)){

    case ICAL_ATTACH_VALUE:
    {
        if (icalattach_get_is_url(a->data.v_attach) &&
            icalattach_get_is_url(b->data.v_attach)) {
        if (strcasecmp(icalattach_get_url(a->data.v_attach),
                   icalattach_get_url(b->data.v_attach)) == 0)
            return ICAL_XLICCOMPARETYPE_EQUAL;
        else
            return ICAL_XLICCOMPARETYPE_NOTEQUAL;
        }
        else {
            if (a->data.v_attach == b->data.v_attach)
            return ICAL_XLICCOMPARETYPE_EQUAL;
            else
            return ICAL_XLICCOMPARETYPE_NOTEQUAL;
        }
    }
        case ICAL_BINARY_VALUE:
    {
        if (a->data.v_attach == b->data.v_attach)
        return ICAL_XLICCOMPARETYPE_EQUAL;
        else
        return ICAL_XLICCOMPARETYPE_NOTEQUAL;
    }

    case ICAL_BOOLEAN_VALUE:
    {
        if (icalvalue_get_boolean(a) == icalvalue_get_boolean(b)){
        return ICAL_XLICCOMPARETYPE_EQUAL;
        } else {
        return ICAL_XLICCOMPARETYPE_NOTEQUAL;
        }
    }

    case ICAL_FLOAT_VALUE:
    {
        if (a->data.v_float > b->data.v_float){
        return ICAL_XLICCOMPARETYPE_GREATER;
        } else if (a->data.v_float < b->data.v_float){
        return ICAL_XLICCOMPARETYPE_LESS;
        } else {
        return ICAL_XLICCOMPARETYPE_EQUAL;
        }
    }

    case ICAL_INTEGER_VALUE:
    case ICAL_UTCOFFSET_VALUE:
    {
        if (a->data.v_int > b->data.v_int){
        return ICAL_XLICCOMPARETYPE_GREATER;
        } else if (a->data.v_int < b->data.v_int){
        return ICAL_XLICCOMPARETYPE_LESS;
        } else {
        return ICAL_XLICCOMPARETYPE_EQUAL;
        }
    }

    case ICAL_DURATION_VALUE: 
    {
        int dur_a = icaldurationtype_as_int(a->data.v_duration);
        int dur_b = icaldurationtype_as_int(b->data.v_duration);

        if (dur_a > dur_b){
        return ICAL_XLICCOMPARETYPE_GREATER;
        } else if (dur_a < dur_b){
        return ICAL_XLICCOMPARETYPE_LESS;
        } else {
        return ICAL_XLICCOMPARETYPE_EQUAL;
        }
    }       


    case ICAL_TEXT_VALUE:
    case ICAL_URI_VALUE:
    case ICAL_CALADDRESS_VALUE:
    case ICAL_TRIGGER_VALUE:
    case ICAL_DATE_VALUE:
    case ICAL_DATETIME_VALUE:
    case ICAL_DATETIMEPERIOD_VALUE:
    case ICAL_QUERY_VALUE:
    case ICAL_RECUR_VALUE:
    {
        int r;

        r =  strcmp(icalvalue_as_ical_string(a),
              icalvalue_as_ical_string(b));

        if (r > 0) {    
        return ICAL_XLICCOMPARETYPE_GREATER;
        } else if (r < 0){
        return ICAL_XLICCOMPARETYPE_LESS;
        } else {
        return ICAL_XLICCOMPARETYPE_EQUAL;
        }

        
    }

    case ICAL_METHOD_VALUE:
    {
        if (icalvalue_get_method(a) == icalvalue_get_method(b)){
        return ICAL_XLICCOMPARETYPE_EQUAL;
        } else {
        return ICAL_XLICCOMPARETYPE_NOTEQUAL;
        }

    }

    case ICAL_STATUS_VALUE:
    {
        if (icalvalue_get_status(a) == icalvalue_get_status(b)){
        return ICAL_XLICCOMPARETYPE_EQUAL;
        } else {
        return ICAL_XLICCOMPARETYPE_NOTEQUAL;
        }

    }

    case ICAL_TRANSP_VALUE:
    {
        if (icalvalue_get_transp(a) == icalvalue_get_transp(b)){
        return ICAL_XLICCOMPARETYPE_EQUAL;
        } else {
        return ICAL_XLICCOMPARETYPE_NOTEQUAL;
        }
    }

    case ICAL_ACTION_VALUE:
        {
        if (icalvalue_get_action(a) == icalvalue_get_action(b)){
        return ICAL_XLICCOMPARETYPE_EQUAL;
        } else {
        return ICAL_XLICCOMPARETYPE_NOTEQUAL;
        }
        }

    case ICAL_PERIOD_VALUE:
    case ICAL_GEO_VALUE:
    case ICAL_NO_VALUE:
    default:
    {
        icalerror_warn("Comparison not implemented for value type");
        return 0;
    }
    }   

}

/** Examine the value and possibly change the kind to agree with the
 *  value 
 */

void icalvalue_reset_kind(icalvalue* value)
{
    if( (value->kind==ICAL_DATETIME_VALUE || value->kind==ICAL_DATE_VALUE )&&
        !icaltime_is_null_time(value->data.v_time) ) {
        
        if(icaltime_is_date(value->data.v_time)){
            value->kind = ICAL_DATE_VALUE;
        } else {
            value->kind = ICAL_DATETIME_VALUE;
        }
    }
       
}

void icalvalue_set_parent(icalvalue* value,
                 icalproperty* property)
{
    value->parent = property;
}

icalproperty* icalvalue_get_parent(icalvalue* value)
{
    return value->parent;
}


int icalvalue_encode_ical_string(const char *szText, char *szEncText, int nMaxBufferLen)
{
    char   *ptr;
    icalvalue *value = 0;

    if ((szText == 0) || (szEncText == 0))
        return 0;
   
    value = icalvalue_new_from_string(ICAL_STRING_VALUE, szText);
    
    if (value == 0)
        return 0;
    
    ptr = icalvalue_text_as_ical_string(value);
    if (ptr == 0)
        return 0;
    
    if ((int)strlen(ptr) >= nMaxBufferLen)
        {
            icalvalue_free (value);
            return 0;
        }

    strcpy(szEncText, ptr);

    icalvalue_free ((icalvalue*)value);

    return 1;
}

/* The remaining interfaces are 'new', 'set' and 'get' for each of the value
   types */