strings.c

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/*
 * Copyright 2004-2020 the Pacemaker project contributors
 *
 * The version control history for this file may have further details.
 *
 * This source code is licensed under the GNU Lesser General Public License
 * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
 */
 
#include <crm_internal.h>
 
#ifndef _GNU_SOURCE
#  define _GNU_SOURCE
#endif
 
#include <regex.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <float.h>  // DBL_MIN
#include <limits.h>
#include <math.h>   // fabs()
#include <bzlib.h>
#include <sys/types.h>
 
char *
crm_itoa_stack(int an_int, char *buffer, size_t len)
{
    if (buffer != NULL) {
        snprintf(buffer, len, "%d", an_int);
    }
 
    return buffer;
}
 
static int
scan_ll(const char *text, long long *result, char **end_text)
{
    long long local_result = PCMK__PARSE_INT_DEFAULT;
    char *local_end_text = NULL;
    int rc = pcmk_rc_ok;
 
    errno = 0;
    if (text != NULL) {
#ifdef ANSI_ONLY
        local_result = (long long) strtol(text, &local_end_text, 10);
#else
        local_result = strtoll(text, &local_end_text, 10);
#endif
        if (errno == ERANGE) {
            rc = EOVERFLOW;
            crm_warn("Integer parsed from %s was clipped to %lld",
                     text, local_result);
 
        } else if (errno != 0) {
            rc = errno;
            local_result = PCMK__PARSE_INT_DEFAULT;
            crm_warn("Could not parse integer from %s (using %d instead): %s",
                    text, PCMK__PARSE_INT_DEFAULT, pcmk_rc_str(rc));
 
        } else if (local_end_text == text) {
            rc = EINVAL;
            local_result = PCMK__PARSE_INT_DEFAULT;
            crm_warn("Could not parse integer from %s (using %d instead): "
                    "No digits found", text, PCMK__PARSE_INT_DEFAULT);
        }
 
        if ((end_text == NULL) && !pcmk__str_empty(local_end_text)) {
            crm_warn("Characters left over after parsing '%s': '%s'",
                     text, local_end_text);
        }
        errno = rc;
    }
    if (end_text != NULL) {
        *end_text = local_end_text;
    }
    if (result != NULL) {
        *result = local_result;
    }
    return rc;
}
 
long long
crm_parse_ll(const char *text, const char *default_text)
{
    long long result;
 
    if (text == NULL) {
        text = default_text;
        if (text == NULL) {
            crm_err("No default conversion value supplied");
            errno = EINVAL;
            return PCMK__PARSE_INT_DEFAULT;
        }
    }
    scan_ll(text, &result, NULL);
    return result;
}
 
int
crm_parse_int(const char *text, const char *default_text)
{
    long long result = crm_parse_ll(text, default_text);
 
    if (result < INT_MIN) {
        // If errno is ERANGE, crm_parse_ll() has already logged a message
        if (errno != ERANGE) {
            crm_err("Conversion of %s was clipped: %lld", text, result);
            errno = ERANGE;
        }
        return INT_MIN;
 
    } else if (result > INT_MAX) {
        // If errno is ERANGE, crm_parse_ll() has already logged a message
        if (errno != ERANGE) {
            crm_err("Conversion of %s was clipped: %lld", text, result);
            errno = ERANGE;
        }
        return INT_MAX;
    }
 
    return (int) result;
}
 
int
pcmk__scan_double(const char *text, double *result, const char *default_text,
                  char **end_text)
{
    int rc = pcmk_rc_ok;
    char *local_end_text = NULL;
 
    CRM_ASSERT(result != NULL);
    *result = PCMK__PARSE_DBL_DEFAULT;
 
    text = (text != NULL) ? text : default_text;
 
    if (text == NULL) {
        rc = EINVAL;
        crm_debug("No text and no default conversion value supplied");
 
    } else {
        errno = 0;
        *result = strtod(text, &local_end_text);
 
        if (errno == ERANGE) {
            /*
             * Overflow: strtod() returns +/- HUGE_VAL and sets errno to
             *           ERANGE
             *
             * Underflow: strtod() returns "a value whose magnitude is
             *            no greater than the smallest normalized
             *            positive" double. Whether ERANGE is set is
             *            implementation-defined.
             */
            const char *over_under;
 
            if (fabs(*result) > DBL_MIN) {
                rc = EOVERFLOW;
                over_under = "over";
            } else {
                rc = pcmk_rc_underflow;
                over_under = "under";
            }
 
            crm_debug("Floating-point value parsed from '%s' would %sflow "
                      "(using %g instead)", text, over_under, *result);
 
        } else if (errno != 0) {
            rc = errno;
            // strtod() set *result = 0 on parse failure
            *result = PCMK__PARSE_DBL_DEFAULT;
 
            crm_debug("Could not parse floating-point value from '%s' (using "
                      "%.1f instead): %s", text, PCMK__PARSE_DBL_DEFAULT,
                      pcmk_rc_str(rc));
 
        } else if (local_end_text == text) {
            // errno == 0, but nothing was parsed
            rc = EINVAL;
            *result = PCMK__PARSE_DBL_DEFAULT;
 
            crm_debug("Could not parse floating-point value from '%s' (using "
                      "%.1f instead): No digits found", text,
                      PCMK__PARSE_DBL_DEFAULT);
 
        } else if (fabs(*result) <= DBL_MIN) {
            /*
             * errno == 0 and text was parsed, but value might have
             * underflowed.
             *
             * ERANGE might not be set for underflow. Check magnitude
             * of *result, but also make sure the input number is not
             * actually zero (0 <= DBL_MIN is not underflow).
             *
             * This check must come last. A parse failure in strtod()
             * also sets *result == 0, so a parse failure would match
             * this test condition prematurely.
             */
            for (const char *p = text; p != local_end_text; p++) {
                if (strchr("0.eE", *p) == NULL) {
                    rc = pcmk_rc_underflow;
                    crm_debug("Floating-point value parsed from '%s' would "
                              "underflow (using %g instead)", text, *result);
                    break;
                }
            }
 
        } else {
            crm_trace("Floating-point value parsed successfully from "
                      "'%s': %g", text, *result);
        }
 
        if ((end_text == NULL) && !pcmk__str_empty(local_end_text)) {
            crm_debug("Characters left over after parsing '%s': '%s'",
                      text, local_end_text);
        }
    }
 
    if (end_text != NULL) {
        *end_text = local_end_text;
    }
 
    return rc;
}
 
int
pcmk__guint_from_hash(GHashTable *table, const char *key, guint default_val,
                      guint *result)
{
    const char *value;
    long long value_ll;
 
    CRM_CHECK((table != NULL) && (key != NULL), return EINVAL);
 
    value = g_hash_table_lookup(table, key);
    if (value == NULL) {
        if (result != NULL) {
            *result = default_val;
        }
        return pcmk_rc_ok;
    }
 
    errno = 0;
    value_ll = crm_parse_ll(value, NULL);
    if (errno != 0) {
        return errno; // Message already logged
    }
    if ((value_ll < 0) || (value_ll > G_MAXUINT)) {
        crm_warn("Could not parse non-negative integer from %s", value);
        return ERANGE;
    }
 
    if (result != NULL) {
        *result = (guint) value_ll;
    }
    return pcmk_rc_ok;
}
 
#ifndef NUMCHARS
#  define   NUMCHARS    "0123456789."
#endif
 
#ifndef WHITESPACE
#  define   WHITESPACE  " \t\n\r\f"
#endif
 
long long
crm_get_msec(const char *input)
{
    const char *num_start = NULL;
    const char *units;
    long long multiplier = 1000;
    long long divisor = 1;
    long long msec = PCMK__PARSE_INT_DEFAULT;
    size_t num_len = 0;
    char *end_text = NULL;
 
    if (input == NULL) {
        return PCMK__PARSE_INT_DEFAULT;
    }
 
    num_start = input + strspn(input, WHITESPACE);
    num_len = strspn(num_start, NUMCHARS);
    if (num_len < 1) {
        return PCMK__PARSE_INT_DEFAULT;
    }
    units = num_start + num_len;
    units += strspn(units, WHITESPACE);
 
    if (!strncasecmp(units, "ms", 2) || !strncasecmp(units, "msec", 4)) {
        multiplier = 1;
        divisor = 1;
    } else if (!strncasecmp(units, "us", 2) || !strncasecmp(units, "usec", 4)) {
        multiplier = 1;
        divisor = 1000;
    } else if (!strncasecmp(units, "s", 1) || !strncasecmp(units, "sec", 3)) {
        multiplier = 1000;
        divisor = 1;
    } else if (!strncasecmp(units, "m", 1) || !strncasecmp(units, "min", 3)) {
        multiplier = 60 * 1000;
        divisor = 1;
    } else if (!strncasecmp(units, "h", 1) || !strncasecmp(units, "hr", 2)) {
        multiplier = 60 * 60 * 1000;
        divisor = 1;
    } else if ((*units != EOS) && (*units != '\n') && (*units != '\r')) {
        return PCMK__PARSE_INT_DEFAULT;
    }
 
    scan_ll(num_start, &msec, &end_text);
    if (msec > (LLONG_MAX / multiplier)) {
        // Arithmetics overflow while multiplier/divisor mutually exclusive
        return LLONG_MAX;
    }
    msec *= multiplier;
    msec /= divisor;
    return msec;
}
 
gboolean
crm_is_true(const char *s)
{
    gboolean ret = FALSE;
 
    if (s != NULL) {
        crm_str_to_boolean(s, &ret);
    }
    return ret;
}
 
int
crm_str_to_boolean(const char *s, int *ret)
{
    if (s == NULL) {
        return -1;
 
    } else if (strcasecmp(s, "true") == 0
               || strcasecmp(s, "on") == 0
               || strcasecmp(s, "yes") == 0 || strcasecmp(s, "y") == 0 || strcasecmp(s, "1") == 0) {
        *ret = TRUE;
        return 1;
 
    } else if (strcasecmp(s, "false") == 0
               || strcasecmp(s, "off") == 0
               || strcasecmp(s, "no") == 0 || strcasecmp(s, "n") == 0 || strcasecmp(s, "0") == 0) {
        *ret = FALSE;
        return 1;
    }
    return -1;
}
 
char *
crm_strip_trailing_newline(char *str)
{
    int len;
 
    if (str == NULL) {
        return str;
    }
 
    for (len = strlen(str) - 1; len >= 0 && str[len] == '\n'; len--) {
        str[len] = '\0';
    }
 
    return str;
}
 
bool
pcmk__starts_with(const char *str, const char *prefix)
{
    const char *s = str;
    const char *p = prefix;
 
    if (!s || !p) {
        return false;
    }
    while (*s && *p) {
        if (*s++ != *p++) {
            return false;
        }
    }
    return (*p == 0);
}
 
static inline bool
ends_with(const char *s, const char *match, bool as_extension)
{
    if (pcmk__str_empty(match)) {
        return true;
    } else if (s == NULL) {
        return false;
    } else {
        size_t slen, mlen;
 
        /* Besides as_extension, we could also check
           !strchr(&match[1], match[0]) but that would be inefficient.
         */
        if (as_extension) {
            s = strrchr(s, match[0]);
            return (s == NULL)? false : !strcmp(s, match);
        }
 
        mlen = strlen(match);
        slen = strlen(s);
        return ((slen >= mlen) && !strcmp(s + slen - mlen, match));
    }
}
 
bool
pcmk__ends_with(const char *s, const char *match)
{
    return ends_with(s, match, false);
}
 
bool
pcmk__ends_with_ext(const char *s, const char *match)
{
    return ends_with(s, match, true);
}
 
/*
 * This re-implements g_str_hash as it was prior to glib2-2.28:
 *
 * https://gitlab.gnome.org/GNOME/glib/commit/354d655ba8a54b754cb5a3efb42767327775696c
 *
 * Note that the new g_str_hash is presumably a *better* hash (it's actually
 * a correct implementation of DJB's hash), but we need to preserve existing
 * behaviour, because the hash key ultimately determines the "sort" order
 * when iterating through GHashTables, which affects allocation of scores to
 * clone instances when iterating through rsc->allowed_nodes.  It (somehow)
 * also appears to have some minor impact on the ordering of a few
 * pseudo_event IDs in the transition graph.
 */
guint
g_str_hash_traditional(gconstpointer v)
{
    const signed char *p;
    guint32 h = 0;
 
    for (p = v; *p != '\0'; p++)
        h = (h << 5) - h + *p;
 
    return h;
}
 
/* used with hash tables where case does not matter */
gboolean
crm_strcase_equal(gconstpointer a, gconstpointer b)
{
    return pcmk__str_eq((const char *)a, (const char *)b, pcmk__str_casei);
}
 
guint
crm_strcase_hash(gconstpointer v)
{
    const signed char *p;
    guint32 h = 0;
 
    for (p = v; *p != '\0'; p++)
        h = (h << 5) - h + g_ascii_tolower(*p);
 
    return h;
}
 
static void
copy_str_table_entry(gpointer key, gpointer value, gpointer user_data)
{
    if (key && value && user_data) {
        g_hash_table_insert((GHashTable*)user_data, strdup(key), strdup(value));
    }
}
 
GHashTable *
crm_str_table_dup(GHashTable *old_table)
{
    GHashTable *new_table = NULL;
 
    if (old_table) {
        new_table = crm_str_table_new();
        g_hash_table_foreach(old_table, copy_str_table_entry, new_table);
    }
    return new_table;
}
 
void
pcmk__add_separated_word(char **list, size_t *len, const char *word,
                         const char *separator)
{
    size_t orig_len, new_len;
 
    CRM_ASSERT(list != NULL);
 
    if (pcmk__str_empty(word)) {
        return;
    }
 
    // Use provided length, or calculate it if not available
    orig_len = (len != NULL)? *len : ((*list == NULL)? 0 : strlen(*list));
 
    // Don't add a separator before the first word in the list
    if (orig_len == 0) {
        separator = "";
 
    // Default to space-separated
    } else if (separator == NULL) {
        separator = " ";
    }
 
    new_len = orig_len + strlen(separator) + strlen(word);
    if (len != NULL) {
        *len = new_len;
    }
 
    // +1 for null terminator
    *list = pcmk__realloc(*list, new_len + 1);
    sprintf(*list + orig_len, "%s%s", separator, word);
}
 
int
pcmk__compress(const char *data, unsigned int length, unsigned int max,
               char **result, unsigned int *result_len)
{
    int rc;
    char *compressed = NULL;
    char *uncompressed = strdup(data);
#ifdef CLOCK_MONOTONIC
    struct timespec after_t;
    struct timespec before_t;
#endif
 
    if (max == 0) {
        max = (length * 1.01) + 601; // Size guaranteed to hold result
    }
 
#ifdef CLOCK_MONOTONIC
    clock_gettime(CLOCK_MONOTONIC, &before_t);
#endif
 
    compressed = calloc((size_t) max, sizeof(char));
    CRM_ASSERT(compressed);
 
    *result_len = max;
    rc = BZ2_bzBuffToBuffCompress(compressed, result_len, uncompressed, length,
                                  CRM_BZ2_BLOCKS, 0, CRM_BZ2_WORK);
    free(uncompressed);
    if (rc != BZ_OK) {
        crm_err("Compression of %d bytes failed: %s " CRM_XS " bzerror=%d",
                length, bz2_strerror(rc), rc);
        free(compressed);
        return pcmk_rc_error;
    }
 
#ifdef CLOCK_MONOTONIC
    clock_gettime(CLOCK_MONOTONIC, &after_t);
 
    crm_trace("Compressed %d bytes into %d (ratio %d:1) in %.0fms",
             length, *result_len, length / (*result_len),
             (after_t.tv_sec - before_t.tv_sec) * 1000 +
             (after_t.tv_nsec - before_t.tv_nsec) / 1e6);
#else
    crm_trace("Compressed %d bytes into %d (ratio %d:1)",
             length, *result_len, length / (*result_len));
#endif
 
    *result = compressed;
    return pcmk_rc_ok;
}
 
char *
crm_strdup_printf(char const *format, ...)
{
    va_list ap;
    int len = 0;
    char *string = NULL;
 
    va_start(ap, format);
    len = vasprintf (&string, format, ap);
    CRM_ASSERT(len > 0);
    va_end(ap);
    return string;
}
 
int
pcmk__parse_ll_range(const char *srcstring, long long *start, long long *end)
{
    char *remainder = NULL;
 
    CRM_ASSERT(start != NULL && end != NULL);
 
    *start = PCMK__PARSE_INT_DEFAULT;
    *end = PCMK__PARSE_INT_DEFAULT;
 
    crm_trace("Attempting to decode: [%s]", srcstring);
    if (pcmk__str_empty(srcstring) || !strcmp(srcstring, "-")) {
        return pcmk_rc_unknown_format;
    }
 
    /* String starts with a dash, so this is either a range with
     * no beginning or garbage.
     * */
    if (*srcstring == '-') {
        int rc = scan_ll(srcstring+1, end, &remainder);
 
        if (rc != pcmk_rc_ok || *remainder != '\0') {
            return pcmk_rc_unknown_format;
        } else {
            return pcmk_rc_ok;
        }
    }
 
    if (scan_ll(srcstring, start, &remainder) != pcmk_rc_ok) {
        return pcmk_rc_unknown_format;
    }
 
    if (*remainder && *remainder == '-') {
        if (*(remainder+1)) {
            char *more_remainder = NULL;
            int rc = scan_ll(remainder+1, end, &more_remainder);
 
            if (rc != pcmk_rc_ok || *more_remainder != '\0') {
                return pcmk_rc_unknown_format;
            }
        }
    } else if (*remainder && *remainder != '-') {
        *start = PCMK__PARSE_INT_DEFAULT;
        return pcmk_rc_unknown_format;
    } else {
        /* The input string contained only one number.  Set start and end
         * to the same value and return pcmk_rc_ok.  This gives the caller
         * a way to tell this condition apart from a range with no end.
         */
        *end = *start;
    }
 
    return pcmk_rc_ok;
}
 
gboolean
pcmk__str_in_list(GList *lst, const gchar *s)
{
    if (lst == NULL) {
        return FALSE;
    }
 
    if (strcmp(lst->data, "*") == 0 && lst->next == NULL) {
        return TRUE;
    }
 
    return g_list_find_custom(lst, s, (GCompareFunc) strcmp) != NULL;
}
 
static bool
str_any_of(bool casei, const char *s, va_list args)
{
    bool rc = false;
 
    if (s != NULL) {
        while (1) {
            const char *ele = va_arg(args, const char *);
 
            if (ele == NULL) {
                break;
            } else if (pcmk__str_eq(s, ele,
                                    casei? pcmk__str_casei : pcmk__str_none)) {
                rc = true;
                break;
            }
        }
    }
    return rc;
}
 
bool
pcmk__strcase_any_of(const char *s, ...)
{
    va_list ap;
    bool rc;
 
    va_start(ap, s);
    rc = str_any_of(true, s, ap);
    va_end(ap);
    return rc;
}
 
bool
pcmk__str_any_of(const char *s, ...)
{
    va_list ap;
    bool rc;
 
    va_start(ap, s);
    rc = str_any_of(false, s, ap);
    va_end(ap);
    return rc;
}
 
bool
pcmk__char_in_any_str(int ch, ...)
{
    bool rc = false;
    va_list ap;
 
    /*
     * Passing a char to va_start() can generate compiler warnings,
     * so ch is declared as an int.
     */
    va_start(ap, ch);
 
    while (1) {
        const char *ele = va_arg(ap, const char *);
 
        if (ele == NULL) {
            break;
        } else if (strchr(ele, ch) != NULL) {
            rc = true;
            break;
        }
    }
 
    va_end(ap);
    return rc;
}
 
int
pcmk_numeric_strcasecmp(const char *s1, const char *s2)
{
    while (*s1 && *s2) {
        if (isdigit(*s1) && isdigit(*s2)) {
            // If node names contain a number, sort numerically
 
            char *end1 = NULL;
            char *end2 = NULL;
            long num1 = strtol(s1, &end1, 10);
            long num2 = strtol(s2, &end2, 10);
 
            // allow ordering e.g. 007 > 7
            size_t len1 = end1 - s1;
            size_t len2 = end2 - s2;
 
            if (num1 < num2) {
                return -1;
            } else if (num1 > num2) {
                return 1;
            } else if (len1 < len2) {
                return -1;
            } else if (len1 > len2) {
                return 1;
            }
            s1 = end1;
            s2 = end2;
        } else {
            // Compare non-digits case-insensitively
            int lower1 = tolower(*s1);
            int lower2 = tolower(*s2);
 
            if (lower1 < lower2) {
                return -1;
            } else if (lower1 > lower2) {
                return 1;
            }
            ++s1;
            ++s2;
        }
    }
    if (!*s1 && *s2) {
        return -1;
    } else if (*s1 && !*s2) {
        return 1;
    }
    return 0;
}
 
/*
 * \brief Sort strings.
 *
 * This is your one-stop function for string comparison.  By default, this
 * function works like g_strcmp0.  That is, like strcmp but a NULL string
 * sorts before a non-NULL string.
 *
 * Behavior can be changed with various flags:
 *
 * - pcmk__str_regex - The second string is a regular expression that the
 *                     first string will be matched against.
 * - pcmk__str_casei - By default, comparisons are done taking case into
 *                     account.  This flag makes comparisons case-insensitive.
 *                     This can be combined with pcmk__str_regex.
 * - pcmk__str_null_matches - If one string is NULL and the other is not,
 *                            still return 0.
 *
 * \param[in] s1    First string to compare
 * \param[in] s2    Second string to compare, or a regular expression to
 *                  match if pcmk__str_regex is set
 * \param[in] flags A bitfield of pcmk__str_flags to modify operation
 *
 * \retval -1 \p s1 is NULL or comes before \p s2
 * \retval  0 \p s1 and \p s2 are equal, or \p s1 is found in \p s2 if
 *            pcmk__str_regex is set
 * \retval  1 \p s2 is NULL or \p s1 comes after \p s2, or if \p s2
 *            is an invalid regular expression, or \p s1 was not found
 *            in \p s2 if pcmk__str_regex is set.
 */
int
pcmk__strcmp(const char *s1, const char *s2, uint32_t flags)
{
    /* If this flag is set, the second string is a regex. */
    if (pcmk_is_set(flags, pcmk__str_regex)) {
        regex_t *r_patt = calloc(1, sizeof(regex_t));
        int reg_flags = REG_EXTENDED | REG_NOSUB;
        int regcomp_rc = 0;
        int rc = 0;
 
        if (s1 == NULL || s2 == NULL) {
            free(r_patt);
            return 1;
        }
 
        if (pcmk_is_set(flags, pcmk__str_casei)) {
            reg_flags |= REG_ICASE;
        }
        regcomp_rc = regcomp(r_patt, s2, reg_flags);
        if (regcomp_rc != 0) {
            rc = 1;
            crm_err("Bad regex '%s' for update: %s", s2, strerror(regcomp_rc));
        } else {
            rc = regexec(r_patt, s1, 0, NULL, 0);
 
            if (rc != 0) {
                rc = 1;
            }
        }
 
        regfree(r_patt);
        free(r_patt);
        return rc;
    }
 
    /* If the strings are the same pointer, return 0 immediately. */
    if (s1 == s2) {
        return 0;
    }
 
    /* If this flag is set, return 0 if either (or both) of the input strings
     * are NULL.  If neither one is NULL, we need to continue and compare
     * them normally.
     */
    if (pcmk_is_set(flags, pcmk__str_null_matches)) {
        if (s1 == NULL || s2 == NULL) {
            return 0;
        }
    }
 
    /* Handle the cases where one is NULL and the str_null_matches flag is not set.
     * A NULL string always sorts to the beginning.
     */
    if (s1 == NULL) {
        return -1;
    } else if (s2 == NULL) {
        return 1;
    }
 
    if (pcmk_is_set(flags, pcmk__str_casei)) {
        return strcasecmp(s1, s2);
    } else {
        return strcmp(s1, s2);
    }
}
 
// Deprecated functions kept only for backward API compatibility
 
gboolean safe_str_neq(const char *a, const char *b);
 
gboolean crm_str_eq(const char *a, const char *b, gboolean use_case);
 
gboolean
safe_str_neq(const char *a, const char *b)
{
    if (a == b) {
        return FALSE;
 
    } else if (a == NULL || b == NULL) {
        return TRUE;
 
    } else if (strcasecmp(a, b) == 0) {
        return FALSE;
    }
    return TRUE;
}
 
gboolean
crm_str_eq(const char *a, const char *b, gboolean use_case)
{
    if (use_case) {
        return g_strcmp0(a, b) == 0;
 
        /* TODO - Figure out which calls, if any, really need to be case independent */
    } else if (a == b) {
        return TRUE;
 
    } else if (a == NULL || b == NULL) {
        /* shouldn't be comparing NULLs */
        return FALSE;
 
    } else if (strcasecmp(a, b) == 0) {
        return TRUE;
    }
    return FALSE;
}