virstring.c

/*
 * Copyright (C) 2012-2015 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *     Daniel P. Berrange <berrange@redhat.com>
 */

#include <config.h>

#include <stdlib.h>
#include <stdio.h>
#include <regex.h>

#include "base64.h"
#include "c-ctype.h"
#include "virstring.h"
#include "virthread.h"
#include "viralloc.h"
#include "virbuffer.h"
#include "virerror.h"
#include "virlog.h"

#define VIR_FROM_THIS VIR_FROM_NONE

VIR_LOG_INIT("util.string");

/*
 * The following virStringSplit & virStringListJoin methods
 * are derived from g_strsplit / g_strjoin in glib2,
 * also available under the LGPLv2+ license terms
 */

/**
 * virStringSplitCount:
 * @string: a string to split
 * @delim: a string which specifies the places at which to split
 *     the string. The delimiter is not included in any of the resulting
 *     strings, unless @max_tokens is reached.
 * @max_tokens: the maximum number of pieces to split @string into.
 *     If this is 0, the string is split completely.
 * @tokcount: If provided, the value is set to the count of pieces the string
 *            was split to excluding the terminating NULL element.
 *
 * Splits a string into a maximum of @max_tokens pieces, using the given
 * @delim. If @max_tokens is reached, the remainder of @string is
 * appended to the last token.
 *
 * As a special case, the result of splitting the empty string "" is an empty
 * vector, not a vector containing a single string. The reason for this
 * special case is that being able to represent an empty vector is typically
 * more useful than consistent handling of empty elements. If you do need
 * to represent empty elements, you'll need to check for the empty string
 * before calling virStringSplit().
 *
 * Return value: a newly-allocated NULL-terminated array of strings. Use
 *    virStringListFree() to free it.
 */
char **
virStringSplitCount(const char *string,
                    const char *delim,
                    size_t max_tokens,
                    size_t *tokcount)
{
    char **tokens = NULL;
    size_t ntokens = 0;
    size_t maxtokens = 0;
    const char *remainder = string;
    char *tmp;
    size_t i;

    if (max_tokens == 0)
        max_tokens = INT_MAX;

    tmp = strstr(remainder, delim);
    if (tmp) {
        size_t delimlen = strlen(delim);

        while (--max_tokens && tmp) {
            size_t len = tmp - remainder;

            if (VIR_RESIZE_N(tokens, maxtokens, ntokens, 1) < 0)
                goto error;

            if (VIR_STRNDUP(tokens[ntokens], remainder, len) < 0)
                goto error;
            ntokens++;
            remainder = tmp + delimlen;
            tmp = strstr(remainder, delim);
        }
    }
    if (*string) {
        if (VIR_RESIZE_N(tokens, maxtokens, ntokens, 1) < 0)
            goto error;

        if (VIR_STRDUP(tokens[ntokens], remainder) < 0)
            goto error;
        ntokens++;
    }

    if (VIR_RESIZE_N(tokens, maxtokens, ntokens, 1) < 0)
        goto error;
    tokens[ntokens++] = NULL;

    if (tokcount)
        *tokcount = ntokens - 1;

    return tokens;

 error:
    for (i = 0; i < ntokens; i++)
        VIR_FREE(tokens[i]);
    VIR_FREE(tokens);
    return NULL;
}


char **
virStringSplit(const char *string,
               const char *delim,
               size_t max_tokens)
{
    return virStringSplitCount(string, delim, max_tokens, NULL);
}


/**
 * virStringListJoin:
 * @strings: a NULL-terminated array of strings to join
 * @delim: a string to insert between each of the strings
 *
 * Joins a number of strings together to form one long string, with the
 * @delim inserted between each of them. The returned string
 * should be freed with VIR_FREE().
 *
 * Returns: a newly-allocated string containing all of the strings joined
 *     together, with @delim between them
 */
char *virStringListJoin(const char **strings,
                        const char *delim)
{
    char *ret;
    virBuffer buf = VIR_BUFFER_INITIALIZER;
    while (*strings) {
        virBufferAdd(&buf, *strings, -1);
        if (*(strings+1))
            virBufferAdd(&buf, delim, -1);
        strings++;
    }
    if (virBufferCheckError(&buf) < 0)
        return NULL;
    ret = virBufferContentAndReset(&buf);
    if (!ret)
        ignore_value(VIR_STRDUP(ret, ""));
    return ret;
}


/**
 * virStringListAdd:
 * @strings: a NULL-terminated array of strings
 * @item: string to add
 *
 * Creates new strings list with all strings duplicated and @item
 * at the end of the list. Callers is responsible for freeing
 * both @strings and returned list.
 */
char **
virStringListAdd(const char **strings,
                 const char *item)
{
    char **ret = NULL;
    size_t i = virStringListLength(strings);

    if (VIR_ALLOC_N(ret, i + 2) < 0)
        goto error;

    for (i = 0; strings && strings[i]; i++) {
        if (VIR_STRDUP(ret[i], strings[i]) < 0)
            goto error;
    }

    if (VIR_STRDUP(ret[i], item) < 0)
        goto error;

    return ret;
 error:
    virStringListFree(ret);
    return NULL;
}


/**
 * virStringListRemove:
 * @strings: a NULL-terminated array of strings
 * @item: string to remove
 *
 * Remove every occurrence of @item in list of @strings.
 */
void
virStringListRemove(char ***strings,
                    const char *item)
{
    size_t r, w = 0;

    if (!strings || !*strings)
        return;

    for (r = 0; (*strings)[r]; r++) {
        if (STREQ((*strings)[r], item)) {
            VIR_FREE((*strings)[r]);
            continue;
        }
        if (r != w)
            (*strings)[w] = (*strings)[r];
        w++;
    }

    if (w == 0) {
        VIR_FREE(*strings);
    } else {
        (*strings)[w] = NULL;
        ignore_value(VIR_REALLOC_N(*strings, w + 1));
    }
}


/**
 * virStringListFree:
 * @str_array: a NULL-terminated array of strings to free
 *
 * Frees a NULL-terminated array of strings, and the array itself.
 * If called on a NULL value, virStringListFree() simply returns.
 */
void virStringListFree(char **strings)
{
    char **tmp = strings;
    while (tmp && *tmp) {
        VIR_FREE(*tmp);
        tmp++;
    }
    VIR_FREE(strings);
}


/**
 * virStringListFreeCount:
 * @strings: array of strings to free
 * @count: number of elements in the array
 *
 * Frees a string array of @count length.
 */
void
virStringListFreeCount(char **strings,
                       size_t count)
{
    size_t i;

    if (!strings)
        return;

    for (i = 0; i < count; i++)
        VIR_FREE(strings[i]);

    VIR_FREE(strings);
}


bool
virStringListHasString(const char **strings,
                       const char *needle)
{
    size_t i = 0;

    if (!strings)
        return false;

    while (strings[i]) {
        if (STREQ(strings[i++], needle))
            return true;
    }

    return false;
}

char *
virStringListGetFirstWithPrefix(char **strings,
                                const char *prefix)
{
    size_t i = 0;

    if (!strings)
        return NULL;

    while (strings[i]) {
        if (STRPREFIX(strings[i], prefix))
            return strings[i] + strlen(prefix);
        i++;
    }

    return NULL;
}

/* Like strtol, but produce an "int" result, and check more carefully.
   Return 0 upon success;  return -1 to indicate failure.
   When END_PTR is NULL, the byte after the final valid digit must be NUL.
   Otherwise, it's like strtol and lets the caller check any suffix for
   validity.  This function is careful to return -1 when the string S
   represents a number that is not representable as an "int". */
int
virStrToLong_i(char const *s, char **end_ptr, int base, int *result)
{
    long int val;
    char *p;
    int err;

    errno = 0;
    val = strtol(s, &p, base); /* exempt from syntax-check */
    err = (errno || (!end_ptr && *p) || p == s || (int) val != val);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* Just like virStrToLong_i, above, but produce an "unsigned int"
 * value.  This version allows twos-complement wraparound of negative
 * numbers. */
int
virStrToLong_ui(char const *s, char **end_ptr, int base, unsigned int *result)
{
    unsigned long int val;
    char *p;
    bool err = false;

    errno = 0;
    val = strtoul(s, &p, base); /* exempt from syntax-check */

    /* This one's tricky.  We _want_ to allow "-1" as shorthand for
     * UINT_MAX regardless of whether long is 32-bit or 64-bit.  But
     * strtoul treats "-1" as ULONG_MAX, and going from ulong back
     * to uint differs depending on the size of long. */
    if (sizeof(long) > sizeof(int) && memchr(s, '-', p - s)) {
        if (-val > UINT_MAX)
            err = true;
        else
            val &= 0xffffffff;
    }

    err |= (errno || (!end_ptr && *p) || p == s || (unsigned int) val != val);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* Just like virStrToLong_i, above, but produce an "unsigned int"
 * value.  This version rejects any negative signs.  */
int
virStrToLong_uip(char const *s, char **end_ptr, int base, unsigned int *result)
{
    unsigned long int val;
    char *p;
    bool err = false;

    errno = 0;
    val = strtoul(s, &p, base); /* exempt from syntax-check */
    err = (memchr(s, '-', p - s) ||
           errno || (!end_ptr && *p) || p == s || (unsigned int) val != val);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* Just like virStrToLong_i, above, but produce a "long" value.  */
int
virStrToLong_l(char const *s, char **end_ptr, int base, long *result)
{
    long int val;
    char *p;
    int err;

    errno = 0;
    val = strtol(s, &p, base); /* exempt from syntax-check */
    err = (errno || (!end_ptr && *p) || p == s);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* Just like virStrToLong_i, above, but produce an "unsigned long"
 * value.  This version allows twos-complement wraparound of negative
 * numbers. */
int
virStrToLong_ul(char const *s, char **end_ptr, int base, unsigned long *result)
{
    unsigned long int val;
    char *p;
    int err;

    errno = 0;
    val = strtoul(s, &p, base); /* exempt from syntax-check */
    err = (errno || (!end_ptr && *p) || p == s);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* Just like virStrToLong_i, above, but produce an "unsigned long"
 * value.  This version rejects any negative signs.  */
int
virStrToLong_ulp(char const *s, char **end_ptr, int base,
                 unsigned long *result)
{
    unsigned long int val;
    char *p;
    int err;

    errno = 0;
    val = strtoul(s, &p, base); /* exempt from syntax-check */
    err = (memchr(s, '-', p - s) ||
           errno || (!end_ptr && *p) || p == s);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* Just like virStrToLong_i, above, but produce a "long long" value.  */
int
virStrToLong_ll(char const *s, char **end_ptr, int base, long long *result)
{
    long long val;
    char *p;
    int err;

    errno = 0;
    val = strtoll(s, &p, base); /* exempt from syntax-check */
    err = (errno || (!end_ptr && *p) || p == s);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* Just like virStrToLong_i, above, but produce an "unsigned long
 * long" value.  This version allows twos-complement wraparound of
 * negative numbers. */
int
virStrToLong_ull(char const *s, char **end_ptr, int base,
                 unsigned long long *result)
{
    unsigned long long val;
    char *p;
    int err;

    errno = 0;
    val = strtoull(s, &p, base); /* exempt from syntax-check */
    err = (errno || (!end_ptr && *p) || p == s);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* Just like virStrToLong_i, above, but produce an "unsigned long
 * long" value.  This version rejects any negative signs.  */
int
virStrToLong_ullp(char const *s, char **end_ptr, int base,
                  unsigned long long *result)
{
    unsigned long long val;
    char *p;
    int err;

    errno = 0;
    val = strtoull(s, &p, base); /* exempt from syntax-check */
    err = (memchr(s, '-', p - s) ||
           errno || (!end_ptr && *p) || p == s);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/* In case thread-safe locales are available */
#if HAVE_NEWLOCALE

static locale_t virLocale;

static int
virLocaleOnceInit(void)
{
    virLocale = newlocale(LC_ALL_MASK, "C", (locale_t)0);
    if (!virLocale)
        return -1;
    return 0;
}

VIR_ONCE_GLOBAL_INIT(virLocale);
#endif


int
virStrToDouble(char const *s,
               char **end_ptr,
               double *result)
{
    double val;
    char *p;
    int err;

    errno = 0;
    val = strtod(s, &p); /* exempt from syntax-check */
    err = (errno || (!end_ptr && *p) || p == s);
    if (end_ptr)
        *end_ptr = p;
    if (err)
        return -1;
    *result = val;
    return 0;
}

/**
 * virDoubleToStr
 *
 * converts double to string with C locale (thread-safe).
 *
 * Returns -1 on error, size of the string otherwise.
 */
int
virDoubleToStr(char **strp, double number)
{
    int ret = -1;

#if HAVE_NEWLOCALE

    locale_t old_loc;

    if (virLocaleInitialize() < 0)
        goto error;

    old_loc = uselocale(virLocale);
    ret = virAsprintf(strp, "%lf", number);
    uselocale(old_loc);

#else

    char *radix, *tmp;
    struct lconv *lc;

    if ((ret = virAsprintf(strp, "%lf", number) < 0))
        goto error;

    lc = localeconv();
    radix = lc->decimal_point;
    tmp = strstr(*strp, radix);
    if (tmp) {
        *tmp = '.';
        if (strlen(radix) > 1)
            memmove(tmp + 1, tmp + strlen(radix), strlen(*strp) - (tmp - *strp));
    }

#endif /* HAVE_NEWLOCALE */
 error:
    return ret;
}


int
virVasprintfInternal(bool report,
                     int domcode,
                     const char *filename,
                     const char *funcname,
                     size_t linenr,
                     char **strp,
                     const char *fmt,
                     va_list list)
{
    int ret;

    if ((ret = vasprintf(strp, fmt, list)) == -1) {
        if (report)
            virReportOOMErrorFull(domcode, filename, funcname, linenr);
        *strp = NULL;
    }
    return ret;
}

int
virAsprintfInternal(bool report,
                    int domcode,
                    const char *filename,
                    const char *funcname,
                    size_t linenr,
                    char **strp,
                    const char *fmt, ...)
{
    va_list ap;
    int ret;

    va_start(ap, fmt);
    ret = virVasprintfInternal(report, domcode, filename,
                               funcname, linenr, strp, fmt, ap);
    va_end(ap);
    return ret;
}

/**
 * virStrncpy
 *
 * A safe version of strncpy.  The last parameter is the number of bytes
 * available in the destination string, *not* the number of bytes you want
 * to copy.  If the destination is not large enough to hold all n of the
 * src string bytes plus a \0, NULL is returned and no data is copied.
 * If the destination is large enough to hold the n bytes plus \0, then the
 * string is copied and a pointer to the destination string is returned.
 */
char *
virStrncpy(char *dest, const char *src, size_t n, size_t destbytes)
{
    char *ret;

    if (n > (destbytes - 1))
        return NULL;

    ret = strncpy(dest, src, n);
    /* strncpy NULL terminates iff the last character is \0.  Therefore
     * force the last byte to be \0
     */
    dest[n] = '\0';

    return ret;
}

/**
 * virStrcpy
 *
 * A safe version of strcpy.  The last parameter is the number of bytes
 * available in the destination string, *not* the number of bytes you want
 * to copy.  If the destination is not large enough to hold all n of the
 * src string bytes plus a \0, NULL is returned and no data is copied.
 * If the destination is large enough to hold the source plus \0, then the
 * string is copied and a pointer to the destination string is returned.
 */
char *
virStrcpy(char *dest, const char *src, size_t destbytes)
{
    return virStrncpy(dest, src, strlen(src), destbytes);
}

/**
 * virSkipSpaces:
 * @str: pointer to the char pointer used
 *
 * Skip potential blanks, this includes space tabs, line feed,
 * carriage returns.
 */
void
virSkipSpaces(const char **str)
{
    const char *cur = *str;

    while (c_isspace(*cur))
        cur++;
    *str = cur;
}

/**
 * virSkipSpacesAndBackslash:
 * @str: pointer to the char pointer used
 *
 * Like virSkipSpaces, but also skip backslashes erroneously emitted
 * by xend
 */
void
virSkipSpacesAndBackslash(const char **str)
{
    const char *cur = *str;

    while (c_isspace(*cur) || *cur == '\\')
        cur++;
    *str = cur;
}

/**
 * virTrimSpaces:
 * @str: string to modify to remove all trailing spaces
 * @endp: track the end of the string
 *
 * If @endp is NULL on entry, then all spaces prior to the trailing
 * NUL in @str are removed, by writing NUL into the appropriate
 * location.  If @endp is non-NULL but points to a NULL pointer,
 * then all spaces prior to the trailing NUL in @str are removed,
 * NUL is written to the new string end, and endp is set to the
 * location of the (new) string end.  If @endp is non-NULL and
 * points to a non-NULL pointer, then that pointer is used as
 * the end of the string, endp is set to the (new) location, but
 * no NUL pointer is written into the string.
 */
void
virTrimSpaces(char *str, char **endp)
{
    char *end;

    if (!endp || !*endp)
        end = str + strlen(str);
    else
        end = *endp;
    while (end > str && c_isspace(end[-1]))
        end--;
    if (endp) {
        if (!*endp)
            *end = '\0';
        *endp = end;
    } else {
        *end = '\0';
    }
}

/**
 * virSkipSpacesBackwards:
 * @str: start of string
 * @endp: on entry, *endp must be NULL or a location within @str, on exit,
 * will be adjusted to skip trailing spaces, or to NULL if @str had nothing
 * but spaces.
 */
void
virSkipSpacesBackwards(const char *str, char **endp)
{
    /* Casting away const is safe, since virTrimSpaces does not
     * modify string with this particular usage.  */
    char *s = (char*) str;

    if (!*endp)
        *endp = s + strlen(s);
    virTrimSpaces(s, endp);
    if (s == *endp)
        *endp = NULL;
}

/**
 * virStringIsEmpty:
 * @str: string to check
 *
 * Returns true if string is empty (may contain only whitespace) or NULL.
 */
bool
virStringIsEmpty(const char *str)
{
    if (!str)
        return true;

    virSkipSpaces(&str);
    return str[0] == '\0';
}

char *
virArgvToString(const char *const *argv)
{
    int len;
    size_t i;
    char *ret, *p;

    for (len = 1, i = 0; argv[i]; i++)
        len += strlen(argv[i]) + 1;

    if (VIR_ALLOC_N(ret, len) < 0)
        return NULL;
    p = ret;

    for (i = 0; argv[i]; i++) {
        if (i != 0)
            *(p++) = ' ';

        strcpy(p, argv[i]);
        p += strlen(argv[i]);
    }

    *p = '\0';

    return ret;
}

/**
 * virStrdup:
 * @dest: where to store duplicated string
 * @src: the source string to duplicate
 * @report: whether to report OOM error, if there is one
 * @domcode: error domain code
 * @filename: caller's filename
 * @funcname: caller's funcname
 * @linenr: caller's line number
 *
 * Wrapper over strdup, which reports OOM error if told so,
 * in which case callers wants to pass @domcode, @filename,
 * @funcname and @linenr which should represent location in
 * caller's body where virStrdup is called from. Consider
 * using VIR_STRDUP which sets these automatically.
 *
 * Returns: 0 for NULL src, 1 on successful copy, -1 otherwise.
 */
int
virStrdup(char **dest,
          const char *src,
          bool report,
          int domcode,
          const char *filename,
          const char *funcname,
          size_t linenr)
{
    *dest = NULL;
    if (!src)
        return 0;
    if (!(*dest = strdup(src))) {
        if (report)
            virReportOOMErrorFull(domcode, filename, funcname, linenr);
        return -1;
    }

    return 1;
}

/**
 * virStrndup:
 * @dest: where to store duplicated string
 * @src: the source string to duplicate
 * @n: how many bytes to copy
 * @report: whether to report OOM error, if there is one
 * @domcode: error domain code
 * @filename: caller's filename
 * @funcname: caller's funcname
 * @linenr: caller's line number
 *
 * Wrapper over strndup, which reports OOM error if told so,
 * in which case callers wants to pass @domcode, @filename,
 * @funcname and @linenr which should represent location in
 * caller's body where virStrndup is called from. Consider
 * using VIR_STRNDUP which sets these automatically.
 *
 * In case @n is smaller than zero, the whole @src string is
 * copied.
 *
 * Returns: 0 for NULL src, 1 on successful copy, -1 otherwise.
 */
int
virStrndup(char **dest,
           const char *src,
           ssize_t n,
           bool report,
           int domcode,
           const char *filename,
           const char *funcname,
           size_t linenr)
{
    *dest = NULL;
    if (!src)
        return 0;
    if (n < 0)
        n = strlen(src);
    if (!(*dest = strndup(src, n))) {
        if (report)
            virReportOOMErrorFull(domcode, filename, funcname, linenr);
        return -1;
    }

   return 1;
}


size_t virStringListLength(const char * const *strings)
{
    size_t i = 0;

    while (strings && strings[i])
        i++;

    return i;
}


/**
 * virStringSortCompare:
 *
 * A comparator function for sorting strings in
 * normal order with qsort().
 */
int virStringSortCompare(const void *a, const void *b)
{
    const char **sa = (const char**)a;
    const char **sb = (const char**)b;

    return strcmp(*sa, *sb);
}

/**
 * virStringSortRevCompare:
 *
 * A comparator function for sorting strings in
 * reverse order with qsort().
 */
int virStringSortRevCompare(const void *a, const void *b)
{
    const char **sa = (const char**)a;
    const char **sb = (const char**)b;

    return strcmp(*sb, *sa);
}

/**
 * virStringSearch:
 * @str: string to search
 * @regexp: POSIX Extended regular expression pattern used for matching
 * @max_matches: maximum number of substrings to return
 * @result: pointer to an array to be filled with NULL terminated list of matches
 *
 * Performs a POSIX extended regex search against a string and return all matching substrings.
 * The @result value should be freed with virStringListFree() when no longer
 * required.
 *
 * @code
 *  char *source = "6853a496-1c10-472e-867a-8244937bd6f0
 *                  773ab075-4cd7-4fc2-8b6e-21c84e9cb391
 *                  bbb3c75c-d60f-43b0-b802-fd56b84a4222
 *                  60c04aa1-0375-4654-8d9f-e149d9885273
 *                  4548d465-9891-4c34-a184-3b1c34a26aa8";
 *  char **matches = NULL;
 *  virStringSearch(source,
 *                  "([a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12})",
 *                  3,
 *                  &matches);
 *
 *  // matches[0] == "6853a496-1c10-472e-867a-8244937bd6f0";
 *  // matches[1] == "773ab075-4cd7-4fc2-8b6e-21c84e9cb391";
 *  // matches[2] == "bbb3c75c-d60f-43b0-b802-fd56b84a4222"
 *  // matches[3] == NULL;
 *
 *  virStringListFree(matches);
 * @endcode
 *
 * Returns: -1 on error, or number of matches
 */
ssize_t
virStringSearch(const char *str,
                const char *regexp,
                size_t max_matches,
                char ***matches)
{
    regex_t re;
    regmatch_t rem;
    size_t nmatches = 0;
    ssize_t ret = -1;
    int rv = -1;

    *matches = NULL;

    VIR_DEBUG("search '%s' for '%s'", str, regexp);

    if ((rv = regcomp(&re, regexp, REG_EXTENDED)) != 0) {
        char error[100];
        regerror(rv, &re, error, sizeof(error));
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Error while compiling regular expression '%s': %s"),
                       regexp, error);
        return -1;
    }

    if (re.re_nsub != 1) {
        virReportError(VIR_ERR_INTERNAL_ERROR,
                       _("Regular expression '%s' must have exactly 1 match group, not %zu"),
                       regexp, re.re_nsub);
        goto cleanup;
    }

    /* '*matches' must always be NULL terminated in every iteration
     * of the loop, so start by allocating 1 element
     */
    if (VIR_EXPAND_N(*matches, nmatches, 1) < 0)
        goto cleanup;

    while ((nmatches - 1) < max_matches) {
        char *match;

        if (regexec(&re, str, 1, &rem, 0) != 0)
            break;

        if (VIR_EXPAND_N(*matches, nmatches, 1) < 0)
            goto cleanup;

        if (VIR_STRNDUP(match, str + rem.rm_so,
                        rem.rm_eo - rem.rm_so) < 0)
            goto cleanup;

        VIR_DEBUG("Got '%s'", match);

        (*matches)[nmatches-2] = match;

        str = str + rem.rm_eo;
    }

    ret = nmatches - 1; /* don't count the trailing null */

 cleanup:
    regfree(&re);
    if (ret < 0) {
        virStringListFree(*matches);
        *matches = NULL;
    }
    return ret;
}

/**
 * virStringMatch:
 * @str: string to match
 * @regexp: POSIX Extended regular expression pattern used for matching
 *
 * Performs a POSIX extended regex match against a string.
 * Returns true on match, false on error or no match.
 */
bool
virStringMatch(const char *str,
               const char *regexp)
{
    regex_t re;
    int rv;

    VIR_DEBUG("match '%s' for '%s'", str, regexp);

    if ((rv = regcomp(&re, regexp, REG_EXTENDED | REG_NOSUB)) != 0) {
        char error[100];
        regerror(rv, &re, error, sizeof(error));
        VIR_WARN("error while compiling regular expression '%s': %s",
                 regexp, error);
        return false;
    }

    rv = regexec(&re, str, 0, NULL, 0);

    regfree(&re);

    return rv == 0;
}

/**
 * virStringReplace:
 * @haystack: the source string to process
 * @oldneedle: the substring to locate
 * @newneedle: the substring to insert
 *
 * Search @haystack and replace all occurrences of @oldneedle with @newneedle.
 *
 * Returns: a new string with all the replacements, or NULL on error
 */
char *
virStringReplace(const char *haystack,
                 const char *oldneedle,
                 const char *newneedle)
{
    virBuffer buf = VIR_BUFFER_INITIALIZER;
    const char *tmp1, *tmp2;
    size_t oldneedlelen = strlen(oldneedle);
    size_t newneedlelen = strlen(newneedle);

    tmp1 = haystack;
    tmp2 = NULL;

    while (tmp1) {
        tmp2 = strstr(tmp1, oldneedle);

        if (tmp2) {
            virBufferAdd(&buf, tmp1, (tmp2 - tmp1));
            virBufferAdd(&buf, newneedle, newneedlelen);
            tmp2 += oldneedlelen;
        } else {
            virBufferAdd(&buf, tmp1, -1);
        }

        tmp1 = tmp2;
    }

    if (virBufferCheckError(&buf) < 0)
        return NULL;

    return virBufferContentAndReset(&buf);
}


/**
 * virStringStripIPv6Brackets:
 * @str: the string to strip
 *
 * Modify the string in-place to remove the leading and closing brackets
 * from an IPv6 address.
 */
void
virStringStripIPv6Brackets(char *str)
{
    size_t len;

    if (!str)
        return;

    len = strlen(str);
    if (str[0] == '[' && str[len - 1] == ']' && strchr(str, ':')) {
        memmove(&str[0], &str[1], len - 2);
        str[len - 2] = '\0';
    }
}


static const char control_chars[] =
    "\x01\x02\x03\x04\x05\x06\x07"
    "\x08" /* \t \n */ "\x0B\x0C" /* \r */ "\x0E\x0F"
    "\x10\x11\x12\x13\x14\x15\x16\x17"
    "\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F";

bool
virStringHasControlChars(const char *str)
{
    if (!str)
        return false;

    return str[strcspn(str, control_chars)] != '\0';
}


VIR_WARNINGS_NO_WLOGICALOP_STRCHR


/**
 * virStringStripControlChars:
 * @str: the string to strip
 *
 * Modify the string in-place to remove the control characters
 * in the interval: [0x01, 0x20)
 */
void
virStringStripControlChars(char *str)
{
    size_t len, i, j;

    if (!str)
        return;

    len = strlen(str);
    for (i = 0, j = 0; i < len; i++) {
        if (strchr(control_chars, str[i]))
            continue;

        str[j++] = str[i];
    }
    str[j] = '\0';
}

/**
 * virStringToUpper:
 * @str: string to capitalize
 * @dst: where to store the new capitalized string
 *
 * Capitalize the string with replacement of all '-' characters for '_'
 * characters. Caller frees the result.
 *
 * Returns 0 if src is NULL, 1 if capitalization was successful, -1 on failure.
 */
int
virStringToUpper(char **dst, const char *src)
{
    char *cap = NULL;
    size_t i;

    if (!src)
        return 0;

    if (VIR_ALLOC_N(cap, strlen(src) + 1) < 0)
        return -1;

    for (i = 0; src[i]; i++) {
        cap[i] = c_toupper(src[i]);
        if (cap[i] == '-')
            cap[i] = '_';
    }

    *dst = cap;
    return 1;
}


/**
 * virStringIsPrintable:
 *
 * Returns true @str contains only printable characters.
 */
bool
virStringIsPrintable(const char *str)
{
    size_t i;

    for (i = 0; str[i]; i++)
        if (!c_isprint(str[i]))
            return false;

    return true;
}


/**
 * virBufferIsPrintable:
 *
 * Returns true if @buf of @buflen contains only printable characters
 */
bool
virStringBufferIsPrintable(const uint8_t *buf,
                           size_t buflen)
{
    size_t i;

    for (i = 0; i < buflen; i++)
        if (!c_isprint(buf[i]))
            return false;

    return true;
}


/**
 * virStringEncodeBase64:
 * @buf: buffer of bytes to encode
 * @buflen: number of bytes to encode
 *
 * Encodes @buf to base 64 and returns the resulting string. The caller is
 * responsible for freeing the result.
 */
char *
virStringEncodeBase64(const uint8_t *buf, size_t buflen)
{
    char *ret;

    base64_encode_alloc((const char *) buf, buflen, &ret);
    if (!ret) {
        virReportOOMError();
        return NULL;
    }

    return ret;
}

/**
 * virStringTrimOptionalNewline:
 * @str: the string to modify in-place
 *
 * Modify @str to remove a single '\n' character
 * from its end, if one exists.
 */
void virStringTrimOptionalNewline(char *str)
{
    char *tmp = str + strlen(str) - 1;
    if (*tmp == '\n')
        *tmp = '\0';
}