path: root/src/libical/icalparser.c

/*======================================================================
 FILE: icalparser.c
 CREATOR: eric 04 August 1999

 (C) COPYRIGHT 2000, Eric Busboom <eric@civicknowledge.com>

 This library 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: https://www.gnu.org/licenses/lgpl-2.1.html

 Or:

    The Mozilla Public License Version 2.0. You may obtain a copy of
    the License at https://www.mozilla.org/MPL/

 This library 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: https://www.gnu.org/licenses/lgpl-2.1.html

 Or:

    The Mozilla Public License Version 2.0. You may obtain a copy of
    the License at https://www.mozilla.org/MPL/

  The Initial Developer of the Original Code is Eric Busboom
 ======================================================================*/

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

#include "icalparser.h"
#include "icalerror.h"
#include "icalmemory.h"
#include "icalvalue.h"
#include "icalproperty_p.h"

#include <ctype.h>
#include <stddef.h>     /* for ptrdiff_t */
#include <stdlib.h>

#define TMP_BUF_SIZE 80
#define MAXIMUM_ALLOWED_PARAMETERS 100
#define MAXIMUM_ALLOWED_MULTIPLE_VALUES 500

struct icalparser_impl
{
    int buffer_full;    /* flag indicates that temp is smaller that
                           data being read into it */
    int continuation_line;      /* last line read was a continuation line */
    size_t tmp_buf_size;
    char temp[TMP_BUF_SIZE];
    icalcomponent *root_component;
    int version;
    int level;
    int lineno;
    icalparser_state state;
    pvl_list components;

    void *line_gen_data;
};

/*
 * New version of strstrip() that does not move the pointer.
 */
static void strstriplt(char *buf)
{
    size_t len;
    int a;

    if (buf == NULL) {
        return;
    }
    if (buf[0] == 0) {
        return;
    }
    len = strlen(buf);
    /* the casts to unsigned char below are to work around isspace asserts
       on Windows due to non-ascii characters becoming negative */
    while ((buf[0] != 0) && (isspace((unsigned char)buf[len - 1]))) {
        buf[--len] = 0;
    }
    if (buf[0] == 0) {
        return;
    }
    a = 0;
    while ((buf[0] != 0) && (isspace((unsigned char)buf[a]))) {
        a++;
    }
    if (a > 0) {
        memmove(buf, &buf[a], len - a + 1);
    }
}

icalparser *icalparser_new(void)
{
    struct icalparser_impl *impl = 0;

    if ((impl = (struct icalparser_impl *)malloc(sizeof(struct icalparser_impl))) == 0) {
        icalerror_set_errno(ICAL_NEWFAILED_ERROR);
        return 0;
    }

    impl->root_component = 0;
    impl->components = pvl_newlist();
    impl->level = 0;
    impl->state = ICALPARSER_SUCCESS;
    impl->tmp_buf_size = TMP_BUF_SIZE;
    impl->buffer_full = 0;
    impl->continuation_line = 0;
    impl->lineno = 0;
    memset(impl->temp, 0, TMP_BUF_SIZE);

    return (icalparser *) impl;
}

void icalparser_free(icalparser *parser)
{
    icalcomponent *c;

    if (parser->root_component != 0) {
        icalcomponent_free(parser->root_component);
    }

    while ((c = pvl_pop(parser->components)) != 0) {
        icalcomponent_free(c);
    }

    pvl_free(parser->components);

    free(parser);
}

void icalparser_set_gen_data(icalparser *parser, void *data)
{
    parser->line_gen_data = data;
}

icalvalue *icalvalue_new_From_string_with_error(icalvalue_kind kind,
                                                char *str, icalproperty ** error);

static char *parser_get_next_char(char c, char *str, int qm)
{
    int quote_mode = 0;
    char *p = str;
    char next_char = *p;
    char prev_char = 0;
    unsigned int cnt = 0;

    while ((cnt < TMP_BUF_SIZE) && (next_char != '\0')) {
        cnt++;
        if ((prev_char != '\0') && (prev_char != '\\')) {
            if (qm == 1 && next_char == '"') {
                /* Encountered a quote, toggle quote mode */
                quote_mode = !quote_mode;
            } else if (quote_mode == 0 && next_char == c) {
                /* Found a matching character out of quote mode, return it */
                return p;
            }
        }

        /* Save the previous character so we can check if it's a backslash in the next iteration */
        prev_char = next_char;
        next_char = *(++p);
    }

    return 0;
}

/** Makes a new tmp buffer out of a substring. */
static char *make_segment(char *start, char *end)
{
    char *buf, *tmp;
    ptrdiff_t size = (ptrdiff_t)(end - start);
    ptrdiff_t cnt = 0;

    buf = icalmemory_new_buffer((size_t)(size + 1));
    strncpy(buf, start, size);
    *(buf + size) = 0;

    tmp = (buf + size);
    while ((cnt < size) && (tmp >= buf) && ((*tmp == '\0') || iswspace((wint_t)*tmp))) {
        cnt++;
        *tmp = 0;
        tmp--;
    }

    return buf;
}

static char *parser_get_prop_name(char *line, char **end)
{
    char *p;
    char *v;
    char *str;

    p = parser_get_next_char(';', line, 1);
    v = parser_get_next_char(':', line, 1);
    if (p == 0 && v == 0) {
        return 0;
    }

    /* There is no ';' or, it is after the ';' that marks the beginning of
       the value */
    if (v != 0 && (p == 0 || p > v)) {
        str = make_segment(line, v);
        *end = v + 1;
    } else {
        str = make_segment(line, p);
        *end = p + 1;
    }

    return str;
}

/** Decode parameter value per RFC6868 */
static void parser_decode_param_value(char *value)
{
    char *in, *out;

    for (in = out = value; *in; in++, out++) {
        if (*in == '^' && strspn(in+1, "n^'")) {
            switch (*++in) {
            case 'n':
                *out = '\n';
                break;

            case '^':
                *out = '^';
                break;

            case '\'':
                *out = '"';
                break;
            }
        } else {
            *out = *in;
        }
    }

    while (*out) *out++ = '\0';
}

static int parser_get_param_name_stack(char *line, char *name, size_t name_length,
                                       char *value, size_t value_length)
{
    char *next, *end_quote;
    size_t requested_name_length, requested_value_length;

    /* The name is everything up to the equals sign */
    next = parser_get_next_char('=', line, 1);

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

    requested_name_length = (ptrdiff_t)(next - line);

    /* Figure out what range of line contains the value (everything after the equals sign) */
    next++;

    if (next[0] == '"') {
        /* Dequote the value */
        next++;

        end_quote = (*next == '"') ? next : parser_get_next_char('"', next, 0);

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

        requested_value_length = (ptrdiff_t)(end_quote - next);
    } else {
        requested_value_length = strlen(next);
    }

    /* There's not enough room in the name or value inputs, we need to fall back
       to parser_get_param_name_heap and use heap-allocated strings */
    if (requested_name_length >= name_length - 1 || requested_value_length >= value_length - 1) {
        return 0;
    }

    strncpy(name, line, requested_name_length);
    name[requested_name_length] = 0;

    strncpy(value, next, requested_value_length);
    value[requested_value_length] = 0;

    parser_decode_param_value(value);

    return 1;
}

static char *parser_get_param_name_heap(char *line, char **end)
{
    /* This is similar to parser_get_param_name_stack except it returns heap
       objects in the return value and the end parameter. This is used in case
       the name or value is longer than the stack-allocated string.
    */
    char *next;
    char *str;

    next = parser_get_next_char('=', line, 1);

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

    str = make_segment(line, next);
    *end = next + 1;
    if (**end == '"') {
        *end = *end + 1;
        next = (**end == '"') ? *end : parser_get_next_char('"', *end, 0);
        if (next == 0) {
            free(str);
            *end = NULL;
            return 0;
        }

        *end = make_segment(*end, next);
    } else {
        *end = make_segment(*end, *end + strlen(*end));
    }

    parser_decode_param_value(*end);

    return str;
}

#if 0
/*keep for historical sake*/
static char *parser_get_next_paramvalue(char *line, char **end)
{
    char *next;
    char *str;

    next = parser_get_next_char(',', line, 1);

    if (next == 0) {
        next = (char *)(size_t) line + (size_t) strlen(line);
    }

    if (next == line) {
        return 0;
    } else {
        str = make_segment(line, next);
        *end = next + 1;
        return str;
    }
}

#endif

static char *icalparser_get_value(char *line, char **end, icalvalue_kind kind)
{
    char *str;
    size_t length = strlen(line);

    _unused(kind);

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

    *end = line + length;
    str = make_segment(line, *end);

    return str;
}

/**
   A property may have multiple values, if the values are separated by
   commas in the content line. This routine will look for the next
   comma after line and will set the next place to start searching in
   end. */

static char *parser_get_next_value(char *line, char **end, icalvalue_kind kind)
{
    char *next = 0;
    char *p;
    char *str;
    size_t length = strlen(line);
    int quoted = 0;

    if (line[0] == '\"' && line[length - 1] == '\"') {
        /* This line is quoted, don't split into multiple values */
        quoted = 1;
    }

    p = line;
    while (!quoted) {

        next = parser_get_next_char(',', p, 1);

        /* Unfortunately, RFC2445 allowed that for the RECUR value, COMMA
           could both separate digits in a list, and it could separate
           multiple recurrence specifications. This is not a friendly
           part of the spec and was deprecated in RFC5545. The following
           weirdness tries to distinguish the two uses. It is probably a HACK */

        if (kind == ICAL_RECUR_VALUE) {
            if (next != 0 && (*end + length) > next + 5 && strncmp(next, "FREQ", 4) == 0) {
                /* The COMMA was followed by 'FREQ', is it a real separator */
                /* Fall through */
            } else if (next != 0) {
                /* Not real, get the next COMMA */
                p = next + 1;
                next = 0;
                continue;
            }
        }
        /* ignore all commas for query and x values. select dtstart, dtend etc ... */
        else if (kind == ICAL_QUERY_VALUE || kind == ICAL_X_VALUE) {
            if (next != 0) {
                p = next + 1;
                continue;
            } else {
                break;
            }
        }

        /* If the comma is preceded by a '\', then it is a literal and
           not a value separator */

        if ((next != 0 && *(next - 1) == '\\') || (next != 0 && *(next - 3) == '\\')
            )
            /*second clause for '/' is on prev line. HACK may be out of bounds */
        {
            p = next + 1;
        } else {
            break;
        }
    }

    if (next == 0) {
        next = (char *)(size_t) line + length;
        *end = next;
    } else {
        *end = next + 1;
    }

    if (next == line) {
        return 0;
    }

    str = make_segment(line, next);
    return str;
}

static char *parser_get_next_parameter(char *line, char **end)
{
    char *next;
    char *v;
    char *str;

    v = parser_get_next_char(':', line, 1);
    next = parser_get_next_char(';', line, 1);

    /* There is no ';' or, it is after the ':' that marks the beginning of
       the value */

    if (next == 0 || next > v) {
        next = parser_get_next_char(':', line, 1);
    }

    if (next != 0) {
        str = make_segment(line, next);
        *end = next + 1;
        return str;
    } else {
        *end = line;
        return 0;
    }
}

char *icalparser_get_line(icalparser *parser,
                          icalparser_line_gen_func line_gen_func)
{
    char *line;
    char *line_p;
    size_t buf_size = parser->tmp_buf_size;

    line_p = line = icalmemory_new_buffer(buf_size);
    line[0] = '\0';

    /* Read lines by calling line_gen_func and putting the data into
       parser->temp. If the line is a continuation line ( begins with a
       space after a newline ) then append the data onto line and read
       again. Otherwise, exit the loop. */

    while (1) {

        /* The first part of the loop deals with the temp buffer,
           which was read on he last pass through the loop. The
           routine is split like this because it has to read lone line
           ahead to determine if a line is a continuation line. */

        /* The tmp buffer is not clear, so transfer the data in it to the
           output. This may be left over from a previous call */
        if (parser->temp[0] != '\0') {

            /* If the last position in the temp buffer is occupied,
               mark the buffer as full. The means we will do another
               read later, because the line is not finished */
            if (parser->temp[parser->tmp_buf_size - 1] == 0 &&
                parser->temp[parser->tmp_buf_size - 2] != '\n' &&
                parser->temp[parser->tmp_buf_size - 2] != 0) {
                parser->buffer_full = 1;
            } else {
                parser->buffer_full = 0;
            }

            /* Copy the temp to the output and clear the temp buffer. */
            if (parser->continuation_line == 1) {
                /* back up the pointer to erase the continuation characters */
                parser->continuation_line = 0;
                line_p--;

                if (*(line_p - 1) == '\r') {
                    line_p--;
                }

                /* copy one space up to eliminate the leading space */
                icalmemory_append_string(&line, &line_p, &buf_size, parser->temp + 1);

            } else {
                icalmemory_append_string(&line, &line_p, &buf_size, parser->temp);
            }

            parser->temp[0] = '\0';
        }

        parser->temp[parser->tmp_buf_size - 1] = 1;     /* Mark end of buffer */

        /****** Here is where the routine gets string data ******************/
        if ((*line_gen_func) (parser->temp, parser->tmp_buf_size, parser->line_gen_data)
            == 0) {     /* Get more data */

            /* If the first position is clear, it means we didn't get
               any more data from the last call to line_ge_func */
            if (parser->temp[0] == '\0') {

                if (line[0] != '\0') {
                    /* There is data in the output, so fall trhough and process it */
                    break;
                } else {
                    /* No data in output; return and signal that there
                       is no more input */
                    free(line);
                    return 0;
                }
            }
        }

        /* If the output line ends in a '\n' and the temp buffer
           begins with a ' ' or tab, then the buffer holds a continuation
           line, so keep reading.  RFC 5545, section 3.1 */

        if (line_p > line + 1 && *(line_p - 1) == '\n'
            && (parser->temp[0] == ' ' || parser->temp[0] == '\t')) {

            parser->continuation_line = 1;

        } else if (parser->buffer_full == 1) {

            /* The buffer was filled on the last read, so read again */

        } else {

            /* Looks like the end of this content line, so break */
            break;
        }
    }

    /* Erase the final newline and/or carriage return */
    if (line_p > line + 1 && *(line_p - 1) == '\n') {
        *(line_p - 1) = '\0';
        if (*(line_p - 2) == '\r') {
            *(line_p - 2) = '\0';
        }

    } else {
        *(line_p) = '\0';
    }

    while ((*line_p == '\0' || iswspace((wint_t) * line_p)) && line_p > line) {
        *line_p = '\0';
        line_p--;
    }

    return line;
}

static void insert_error(icalcomponent *comp, const char *text,
                         const char *message, icalparameter_xlicerrortype type)
{
    char temp[1024];

    if (text == 0) {
        snprintf(temp, 1024, "%s:", message);
    } else {
        snprintf(temp, 1024, "%s: %s", message, text);
    }

    icalcomponent_add_property(
        comp,
        icalproperty_vanew_xlicerror(temp, icalparameter_new_xlicerrortype(type), 0));
}

static int line_is_blank(char *line)
{
    int i = 0;

    for (i = 0; *(line + i) != 0; i++) {
        char c = *(line + i);

        if (c != ' ' && c != '\n' && c != '\t') {
            return 0;
        }
    }

    return 1;
}

icalcomponent *icalparser_parse(icalparser *parser,
                                icalparser_line_gen_func line_gen_func)
{
    char *line;
    icalcomponent *c = 0;
    icalcomponent *root = 0;
    icalerrorstate es = icalerror_get_error_state(ICAL_MALFORMEDDATA_ERROR);
    int cont;

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

    icalerror_set_error_state(ICAL_MALFORMEDDATA_ERROR, ICAL_ERROR_NONFATAL);

    do {
        line = icalparser_get_line(parser, line_gen_func);

        if ((c = icalparser_add_line(parser, line)) != 0) {

            if (icalcomponent_get_parent(c) != 0) {
                /* This is bad news... assert? */
            }

            assert(parser->root_component == 0);
            assert(pvl_count(parser->components) == 0);

            if (root == 0) {
                /* Just one component */
                root = c;
            } else if (icalcomponent_isa(root) != ICAL_XROOT_COMPONENT) {
                /*Got a second component, so move the two components under
                   an XROOT container */
                icalcomponent *tempc = icalcomponent_new(ICAL_XROOT_COMPONENT);

                icalcomponent_add_component(tempc, root);
                icalcomponent_add_component(tempc, c);
                root = tempc;
            } else if (icalcomponent_isa(root) == ICAL_XROOT_COMPONENT) {
                /* Already have an XROOT container, so add the component
                   to it */
                icalcomponent_add_component(root, c);

            } else {
                /* Badness */
                assert(0);
            }

            c = 0;
        }
        cont = 0;
        if (line != 0) {
            icalmemory_free_buffer(line);
            cont = 1;
        }
    } while (cont);

    icalerror_set_error_state(ICAL_MALFORMEDDATA_ERROR, es);

    return root;
}

icalcomponent *icalparser_add_line(icalparser *parser, char *line)
{
    char *str;
    char *end;
    int pcount = 0;
    int vcount = 0;
    icalproperty *prop;
    icalproperty_kind prop_kind;
    icalvalue *value;
    icalvalue_kind value_kind = ICAL_NO_VALUE;

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

    if (line == 0) {
        parser->state = ICALPARSER_ERROR;
        return 0;
    }

    if (line_is_blank(line) == 1) {
        return 0;
    }

    /* Begin by getting the property name at the start of the line. The
       property name may end up being "BEGIN" or "END" in which case it
       is not really a property, but the marker for the start or end of
       a component */

    end = 0;
    str = parser_get_prop_name(line, &end);

    if (str == 0 || *str == '\0') {
        /* Could not get a property name */
        icalcomponent *tail = pvl_data(pvl_tail(parser->components));

        if (tail) {
            insert_error(
                tail, line,
                "Got a data line, but could not find a property name or component begin tag",
                ICAL_XLICERRORTYPE_COMPONENTPARSEERROR);
        }
        tail = 0;
        parser->state = ICALPARSER_ERROR;
        icalmemory_free_buffer(str);
        str = NULL;
        return 0;
    }

    /**********************************************************************
     * Handle begin and end of components
     **********************************************************************/
    /* If the property name is BEGIN or END, we are actually
       starting or ending a new component */

    if (strcasecmp(str, "BEGIN") == 0) {
        icalcomponent *c;
        icalcomponent_kind comp_kind;

        parser->level++;
        icalmemory_free_buffer(str);
        str = parser_get_next_value(end, &end, value_kind);

        comp_kind = icalenum_string_to_component_kind(str);

        c = icalcomponent_new(comp_kind);

        if (c == 0) {
            c = icalcomponent_new(ICAL_XLICINVALID_COMPONENT);
            insert_error(c, str, "Parse error in component name",
                         ICAL_XLICERRORTYPE_COMPONENTPARSEERROR);
        }

        pvl_push(parser->components, c);

        parser->state = ICALPARSER_BEGIN_COMP;

        icalmemory_free_buffer(str);
        str = NULL;
        return 0;

    } else if (strcasecmp(str, "END") == 0) {
        icalcomponent *tail;

        parser->level--;
        icalmemory_free_buffer(str);
        str = parser_get_next_value(end, &end, value_kind);

        /* Pop last component off of list and add it to the second-to-last */
        parser->root_component = pvl_pop(parser->components);

        tail = pvl_data(pvl_tail(parser->components));

        if (tail != 0) {
            icalcomponent_add_component(tail, parser->root_component);
        }

        tail = 0;
        icalmemory_free_buffer(str);
        str = NULL;

        if (parser->level < 0) {
            // Encountered an END before any BEGIN, this must be invalid data
            icalerror_warn("Encountered END before BEGIN");

            parser->state = ICALPARSER_ERROR;
            parser->level = 0;
            return 0;
        } else if (parser->level == 0) {
            /* Return the component if we are back to the 0th level */
            icalcomponent *rtrn;

            if (pvl_count(parser->components) != 0) {
                /* There are still components on the stack -- this means
                   that one of them did not have a proper "END" */
                pvl_push(parser->components, parser->root_component);
                (void)icalparser_clean(parser); /* may reset parser->root_component */
            }

            assert(pvl_count(parser->components) == 0);

            parser->state = ICALPARSER_SUCCESS;
            rtrn = parser->root_component;
            parser->root_component = 0;
            return rtrn;

        } else {
            parser->state = ICALPARSER_END_COMP;
            return 0;
        }
    }

    /* There is no point in continuing if we have not seen a
       component yet */

    if (pvl_data(pvl_tail(parser->components)) == 0) {
        parser->state = ICALPARSER_ERROR;
        icalmemory_free_buffer(str);
        str = NULL;
        return 0;
    }

    /**********************************************************************
     * Handle property names
     **********************************************************************/

    /* At this point, the property name really is a property name,
       (Not a component name) so make a new property and add it to
       the component */

    prop_kind = icalproperty_string_to_kind(str);

    prop = icalproperty_new(prop_kind);

    if (prop != 0) {
        icalcomponent *tail = pvl_data(pvl_tail(parser->components));

        if (prop_kind == ICAL_X_PROPERTY) {
            icalproperty_set_x_name(prop, str);
        }

        icalcomponent_add_property(tail, prop);

        /* Set the value kind for the default for this type of
           property. This may be re-set by a VALUE parameter */
        value_kind = icalproperty_kind_to_value_kind(icalproperty_isa(prop));

    } else {
        icalcomponent *tail = pvl_data(pvl_tail(parser->components));

        insert_error(tail, str, "Parse error in property name",
                     ICAL_XLICERRORTYPE_PROPERTYPARSEERROR);

        tail = 0;
        parser->state = ICALPARSER_ERROR;
        icalmemory_free_buffer(str);
        str = NULL;
        return 0;
    }

    icalmemory_free_buffer(str);
    str = NULL;

    /**********************************************************************
     * Handle parameter values
     **********************************************************************/

    /* Now, add any parameters to the last property */

    while (pcount < MAXIMUM_ALLOWED_PARAMETERS) {
        if (*(end - 1) == ':') {
            /* if the last separator was a ":" and the value is a
               URL, icalparser_get_next_parameter will find the
               ':' in the URL, so better break now. */
            break;
        }

        icalmemory_free_buffer(str);
        str = parser_get_next_parameter(end, &end);
        strstriplt(str);
        if (str != 0) {
            char *name_heap = 0;
            char *pvalue_heap = 0;
            char name_stack[TMP_BUF_SIZE];
            char pvalue_stack[TMP_BUF_SIZE];
            char *name = name_stack;
            char *pvalue = pvalue_stack;

            icalparameter *param = 0;
            icalparameter_kind kind;
            icalcomponent *tail = pvl_data(pvl_tail(parser->components));

            if (!parser_get_param_name_stack(str, name_stack, sizeof(name_stack),
                                             pvalue_stack, sizeof(pvalue_stack))) {
                name_heap = parser_get_param_name_heap(str, &pvalue_heap);

                name = name_heap;
                pvalue = pvalue_heap;

                if (name_heap == 0) {
                    /* 'tail' defined above */
                    insert_error(tail, str, "Can't parse parameter name",
                                 ICAL_XLICERRORTYPE_PARAMETERNAMEPARSEERROR);
                    tail = 0;
                    break;
                }
            }

            kind = icalparameter_string_to_kind(name);

            if (kind == ICAL_X_PARAMETER) {
                param = icalparameter_new(ICAL_X_PARAMETER);
                if (param != 0) {
                    icalparameter_set_xname(param, name);
                    icalparameter_set_xvalue(param, pvalue);
                }
            } else if (kind == ICAL_IANA_PARAMETER) {
                ical_unknown_token_handling tokHandlingSetting =
                    ical_get_unknown_token_handling_setting();
                if (tokHandlingSetting == ICAL_DISCARD_TOKEN) {
                    if (name_heap) {
                        icalmemory_free_buffer(name_heap);
                        name_heap = 0;
                    }
                    if (pvalue_heap) {
                        icalmemory_free_buffer(pvalue_heap);
                        pvalue_heap = 0;
                    }
                    continue;
                }

                param = icalparameter_new(ICAL_IANA_PARAMETER);

                if (param != 0) {
                    icalparameter_set_xname(param, name);
                    icalparameter_set_xvalue(param, pvalue);
                }
            } else if (kind == ICAL_TZID_PARAMETER && *(end - 1) != ';') {
                /*
                   Special case handling for TZID to work around invalid incoming data.
                   For example, Google Calendar will send back stuff like this:
                   DTSTART;TZID=GMT+05:30:20120904T020000

                   In this case we read to the next semicolon or the last colon rather
                   than the first colon.  This way the TZID will become GMT+05:30 rather
                   than trying to parse the date-time as 30:20120904T020000.

                   This also handles properties that look like this:
                   DTSTART;TZID=GMT+05:30;VALUE=DATE-TIME:20120904T020000
                 */
                char *lastColon = 0;
                char *nextColon = end;
                char *nextSemicolon = parser_get_next_char(';', end, 1);

                /* Find the last colon in the line */
                do {
                    nextColon = parser_get_next_char(':', nextColon, 1);

                    if (nextColon) {
                        lastColon = nextColon;
                    }
                } while (nextColon);

                if (lastColon && nextSemicolon && nextSemicolon < lastColon) {
                    /*
                       Ensures that we don't read past a semicolon

                       Handles the following line:
                       DTSTART;TZID=GMT+05:30;VALUE=DATE-TIME:20120904T020000
                     */
                    lastColon = nextSemicolon;
                }

                /*
                   Rebuild str so that it includes everything up to the next semicolon
                   or the last colon. So given the above example, str will go from
                   "TZID=GMT+05" to "TZID=GMT+05:30"
                 */
                if (lastColon && *(lastColon + 1) != 0) {
                    char *strStart = line + strlen(name) + 2;

                    end = lastColon + 1;

                    icalmemory_free_buffer(str);
                    str = make_segment(strStart, end - 1);
                }

                /* Reparse the parameter name and value with the new segment */
                if (!parser_get_param_name_stack(str, name_stack, sizeof(name_stack),
                                                 pvalue_stack, sizeof(pvalue_stack))) {
                    if (pvalue_heap) {
                        icalmemory_free_buffer(pvalue_heap);
                        pvalue_heap = 0;
                        pvalue = 0;
                    }
                    if (name_heap) {
                        icalmemory_free_buffer(name_heap);
                        name = 0;
                    }
                    name_heap = parser_get_param_name_heap(str, &pvalue_heap);
                    pvalue = pvalue_heap;
                }
                param = icalparameter_new_from_value_string(kind, pvalue);
            } else if (kind != ICAL_NO_PARAMETER) {
                param = icalparameter_new_from_value_string(kind, pvalue);
            } else {
                /* Error. Failed to parse the parameter */
                /* 'tail' defined above */

                /* Change for mozilla */
                /* have the option of being flexible towards unsupported parameters */
#if ICAL_ERRORS_ARE_FATAL == 1
                insert_error(tail, str, "Can't parse parameter name",
                             ICAL_XLICERRORTYPE_PARAMETERNAMEPARSEERROR);
                tail = 0;
                parser->state = ICALPARSER_ERROR;
                if (pvalue_heap) {
                    icalmemory_free_buffer(pvalue_heap);
                    pvalue = 0;
                }
                if (name_heap) {
                    icalmemory_free_buffer(name_heap);
                    name = 0;
                }
                icalmemory_free_buffer(str);
                str = NULL;
                return 0;
#else
                if (name_heap) {
                    icalmemory_free_buffer(name_heap);
                    name_heap = 0;
                }
                if (pvalue_heap) {
                    icalmemory_free_buffer(pvalue_heap);
                    pvalue_heap = 0;
                }
                icalmemory_free_buffer(str);
                str = NULL;
                continue;
#endif
            }

            if (pvalue_heap) {
                icalmemory_free_buffer(pvalue_heap);
                pvalue_heap = 0;
            }

            if (name_heap) {
                icalmemory_free_buffer(name_heap);
                name_heap = 0;
            }

            if (param == 0) {
                /* 'tail' defined above */
                insert_error(tail, str, "Can't parse parameter value",
                             ICAL_XLICERRORTYPE_PARAMETERVALUEPARSEERROR);

                tail = 0;
                parser->state = ICALPARSER_ERROR;

                icalmemory_free_buffer(str);
                str = NULL;

                continue;
            }

            /* If it is a VALUE parameter, set the kind of value */
            if (icalparameter_isa(param) == ICAL_VALUE_PARAMETER) {
                value_kind =
                    (icalvalue_kind)icalparameter_value_to_value_kind(
                        icalparameter_get_value(param));

                if (!icalproperty_value_kind_is_valid(prop_kind, value_kind)) {

                    /* Ooops, invalid VALUE parameter, so reset the value_kind */

                    const char *err_str = "Invalid VALUE type for property";
                    const char *prop_str = icalproperty_kind_to_string(prop_kind);
                    size_t tmp_buf_len = strlen(err_str) + strlen(prop_str) + 2;
                    char *tmp_buf = icalmemory_tmp_buffer(tmp_buf_len);
                    snprintf(tmp_buf, tmp_buf_len, "%s %s", err_str, prop_str);

                    insert_error(tail, str, tmp_buf,
                                 ICAL_XLICERRORTYPE_PARAMETERVALUEPARSEERROR);

                    value_kind = icalproperty_kind_to_value_kind(prop_kind);

                    icalparameter_free(param);
                    tail = 0;
                    parser->state = ICALPARSER_ERROR;

                    icalmemory_free_buffer(str);
                    str = NULL;
                    pcount++;
                    continue;
                }
            }

            /* Everything is OK, so add the parameter */
            icalproperty_add_parameter(prop, param);
            tail = 0;
            icalmemory_free_buffer(str);
            str = NULL;
            pcount++;

        } else {
            /* str is NULL */
            break;
        }

    }   /* while(1) */

    /**********************************************************************
     * Handle values
     **********************************************************************/

    /* Look for values. If there are ',' characters in the values,
       then there are multiple values, so clone the current
       parameter and add one part of the value to each clone */

    vcount = 0;
    while (vcount < MAXIMUM_ALLOWED_MULTIPLE_VALUES) {
        /* Only some properties can have multiple values. This list was taken
           from rfc5545. Also added the x-properties, because the spec actually
           says that commas should be escaped. For x-properties, other apps may
           depend on that behaviour
         */
        icalmemory_free_buffer(str);
        str = NULL;

        if (icalproperty_value_kind_is_multivalued(prop_kind, &value_kind)) {
            str = parser_get_next_value(end, &end, value_kind);
        } else {
            str = icalparser_get_value(end, &end, value_kind);
        }
        strstriplt(str);

        if (str != 0) {

            if (vcount > 0) {
                /* Actually, only clone after the second value */
                icalproperty *clone = icalproperty_new_clone(prop);
                icalcomponent *tail = pvl_data(pvl_tail(parser->components));

                icalcomponent_add_property(tail, clone);
                prop = clone;
                tail = 0;
            }

            value = icalvalue_new_from_string(value_kind, str);

            /* Don't add properties without value */
            if (value == 0) {
                char temp[200]; /* HACK */

                icalproperty_kind prop_kind = icalproperty_isa(prop);
                icalcomponent *tail = pvl_data(pvl_tail(parser->components));

                snprintf(temp, sizeof(temp),
                         "Can't parse as %s value in %s property. Removing entire property",
                         icalvalue_kind_to_string(value_kind),
                         icalproperty_kind_to_string(prop_kind));

                insert_error(tail, str, temp, ICAL_XLICERRORTYPE_VALUEPARSEERROR);

                /* Remove the troublesome property */
                icalcomponent_remove_property(tail, prop);
                icalproperty_free(prop);
                prop = 0;
                tail = 0;
                parser->state = ICALPARSER_ERROR;

                icalmemory_free_buffer(str);
                str = NULL;
                return 0;

            } else {
                vcount++;
                icalproperty_set_value(prop, value);
            }
            icalmemory_free_buffer(str);
            str = NULL;

        } else {
#if ICAL_ALLOW_EMPTY_PROPERTIES
            /* Don't replace empty properties with an error.
               Set an empty length string (not null) as the value instead */
            if (vcount == 0) {
                icalproperty_set_value(prop, icalvalue_new(ICAL_NO_VALUE));
            }

            break;
#else
            if (vcount == 0) {
                char temp[200]; /* HACK */

                icalproperty_kind prop_kind = icalproperty_isa(prop);
                icalcomponent *tail = pvl_data(pvl_tail(parser->components));

                snprintf(temp, sizeof(temp), "No value for %s property. Removing entire property",
                         icalproperty_kind_to_string(prop_kind));

                insert_error(tail, str, temp, ICAL_XLICERRORTYPE_VALUEPARSEERROR);

                /* Remove the troublesome property */
                icalcomponent_remove_property(tail, prop);
                icalproperty_free(prop);
                prop = 0;
                tail = 0;
                parser->state = ICALPARSER_ERROR;
                return 0;
            } else {

                break;
            }
#endif
        }
    }

    /****************************************************************
     * End of component parsing.
     *****************************************************************/

    if (pvl_data(pvl_tail(parser->components)) == 0 && parser->level == 0) {
        /* HACK. Does this clause ever get executed? */
        parser->state = ICALPARSER_SUCCESS;
        assert(0);
        return parser->root_component;
    } else {
        parser->state = ICALPARSER_IN_PROGRESS;
        return 0;
    }
}

icalparser_state icalparser_get_state(icalparser *parser)
{
    return parser->state;
}

icalcomponent *icalparser_clean(icalparser *parser)
{
    icalcomponent *tail;

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

    /* We won't get a clean exit if some components did not have an
       "END" tag. Clear off any component that may be left in the list */

    while ((tail = pvl_data(pvl_tail(parser->components))) != 0) {

        insert_error(tail, " ",
                     "Missing END tag for this component. Closing component at end of input.",
                     ICAL_XLICERRORTYPE_COMPONENTPARSEERROR);

        parser->root_component = pvl_pop(parser->components);
        tail = pvl_data(pvl_tail(parser->components));

        if (tail != 0 && parser->root_component != NULL) {
            if (icalcomponent_get_parent(parser->root_component) != 0) {
                icalerror_warn(
                    "icalparser_clean is trying to attach a component for the second time");
            } else {
                icalcomponent_add_component(tail, parser->root_component);
            }
        }
    }

    return parser->root_component;
}

struct slg_data
{
    const char *pos;
    const char *str;
};

char *icalparser_string_line_generator(char *out, size_t buf_size, void *d)
{
    int replace_cr = 0;
    char *n;
    size_t size;
    struct slg_data *data = (struct slg_data *)d;

    if (data->pos == 0) {
        data->pos = data->str;

        /* Skip the UTF-8 marker at the beginning of the string */
        if (((unsigned char) data->pos[0]) == 0xEF &&
            ((unsigned char) data->pos[1]) == 0xBB &&
            ((unsigned char) data->pos[2]) == 0xBF) {
            data->pos += 3;
        }
    }

    /* If the pointer is at the end of the string, we are done */
    if (*(data->pos) == 0) {
        return 0;
    }

    n = strchr(data->pos, '\n');

    if (n == 0) {
        n = strchr(data->pos, '\r'); /* support malformed input with only CR and no LF
                                        (e.g. from Kerio Connect Server) */
        if(n == 0) {
            size = strlen(data->pos);
        } else {
            n++; /* include CR in output - will be replaced by LF later on */
            replace_cr = 1;
            size = (size_t) (ptrdiff_t) (n - data->pos);
        }
    } else {
        n++;    /* include newline in output */
        size = (size_t) (ptrdiff_t) (n - data->pos);
    }

    if (size > buf_size - 1) {
        size = buf_size - 1;
    }

    strncpy(out, data->pos, size);

    if(replace_cr) {
        *(out + size - 1) = '\n';
    }
    *(out + size) = '\0';

    data->pos += size;

    return out;
}

icalcomponent *icalparser_parse_string(const char *str)
{
    icalcomponent *c;
    struct slg_data d;
    icalparser *p;

    icalerrorstate es = icalerror_get_error_state(ICAL_MALFORMEDDATA_ERROR);

    d.pos = 0;
    d.str = str;

    p = icalparser_new();
    icalparser_set_gen_data(p, &d);

    icalerror_set_error_state(ICAL_MALFORMEDDATA_ERROR, ICAL_ERROR_NONFATAL);

    c = icalparser_parse(p, icalparser_string_line_generator);

    icalerror_set_error_state(ICAL_MALFORMEDDATA_ERROR, es);

    icalparser_free(p);

    return c;
}