new file mode 100644
--- /dev/null
+++ b/src/strings.c
@@ -0,0 +1,1563 @@
+/* vi:set ts=8 sts=4 sw=4 noet:
+ *
+ * VIM - Vi IMproved	by Bram Moolenaar
+ *
+ * Do ":help uganda"  in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ * See README.txt for an overview of the Vim source code.
+ */
+
+/*
+ * strings.c: string manipulation functions
+ */
+
+#include "vim.h"
+
+/*
+ * Copy "string" into newly allocated memory.
+ */
+    char_u *
+vim_strsave(char_u *string)
+{
+    char_u	*p;
+    size_t	len;
+
+    len = STRLEN(string) + 1;
+    p = alloc(len);
+    if (p != NULL)
+	mch_memmove(p, string, len);
+    return p;
+}
+
+/*
+ * Copy up to "len" bytes of "string" into newly allocated memory and
+ * terminate with a NUL.
+ * The allocated memory always has size "len + 1", also when "string" is
+ * shorter.
+ */
+    char_u *
+vim_strnsave(char_u *string, size_t len)
+{
+    char_u	*p;
+
+    p = alloc(len + 1);
+    if (p != NULL)
+    {
+	STRNCPY(p, string, len);
+	p[len] = NUL;
+    }
+    return p;
+}
+
+/*
+ * Same as vim_strsave(), but any characters found in esc_chars are preceded
+ * by a backslash.
+ */
+    char_u *
+vim_strsave_escaped(char_u *string, char_u *esc_chars)
+{
+    return vim_strsave_escaped_ext(string, esc_chars, '\\', FALSE);
+}
+
+/*
+ * Same as vim_strsave_escaped(), but when "bsl" is TRUE also escape
+ * characters where rem_backslash() would remove the backslash.
+ * Escape the characters with "cc".
+ */
+    char_u *
+vim_strsave_escaped_ext(
+    char_u	*string,
+    char_u	*esc_chars,
+    int		cc,
+    int		bsl)
+{
+    char_u	*p;
+    char_u	*p2;
+    char_u	*escaped_string;
+    unsigned	length;
+    int		l;
+
+    /*
+     * First count the number of backslashes required.
+     * Then allocate the memory and insert them.
+     */
+    length = 1;				// count the trailing NUL
+    for (p = string; *p; p++)
+    {
+	if (has_mbyte && (l = (*mb_ptr2len)(p)) > 1)
+	{
+	    length += l;		// count a multibyte char
+	    p += l - 1;
+	    continue;
+	}
+	if (vim_strchr(esc_chars, *p) != NULL || (bsl && rem_backslash(p)))
+	    ++length;			// count a backslash
+	++length;			// count an ordinary char
+    }
+    escaped_string = alloc(length);
+    if (escaped_string != NULL)
+    {
+	p2 = escaped_string;
+	for (p = string; *p; p++)
+	{
+	    if (has_mbyte && (l = (*mb_ptr2len)(p)) > 1)
+	    {
+		mch_memmove(p2, p, (size_t)l);
+		p2 += l;
+		p += l - 1;		// skip multibyte char
+		continue;
+	    }
+	    if (vim_strchr(esc_chars, *p) != NULL || (bsl && rem_backslash(p)))
+		*p2++ = cc;
+	    *p2++ = *p;
+	}
+	*p2 = NUL;
+    }
+    return escaped_string;
+}
+
+/*
+ * Return TRUE when 'shell' has "csh" in the tail.
+ */
+    int
+csh_like_shell(void)
+{
+    return (strstr((char *)gettail(p_sh), "csh") != NULL);
+}
+
+/*
+ * Escape "string" for use as a shell argument with system().
+ * This uses single quotes, except when we know we need to use double quotes
+ * (MS-DOS and MS-Windows not using PowerShell and without 'shellslash' set).
+ * PowerShell also uses a novel escaping for enclosed single quotes - double
+ * them up.
+ * Escape a newline, depending on the 'shell' option.
+ * When "do_special" is TRUE also replace "!", "%", "#" and things starting
+ * with "<" like "<cfile>".
+ * When "do_newline" is FALSE do not escape newline unless it is csh shell.
+ * Returns the result in allocated memory, NULL if we have run out.
+ */
+    char_u *
+vim_strsave_shellescape(char_u *string, int do_special, int do_newline)
+{
+    unsigned	length;
+    char_u	*p;
+    char_u	*d;
+    char_u	*escaped_string;
+    int		l;
+    int		csh_like;
+    char_u	*shname;
+    int		powershell;
+# ifdef MSWIN
+    int		double_quotes;
+# endif
+
+    // Only csh and similar shells expand '!' within single quotes.  For sh and
+    // the like we must not put a backslash before it, it will be taken
+    // literally.  If do_special is set the '!' will be escaped twice.
+    // Csh also needs to have "\n" escaped twice when do_special is set.
+    csh_like = csh_like_shell();
+
+    // PowerShell uses it's own version for quoting single quotes
+    shname = gettail(p_sh);
+    powershell = strstr((char *)shname, "pwsh") != NULL;
+# ifdef MSWIN
+    powershell = powershell || strstr((char *)shname, "powershell") != NULL;
+    // PowerShell only accepts single quotes so override shellslash.
+    double_quotes = !powershell && !p_ssl;
+# endif
+
+    // First count the number of extra bytes required.
+    length = (unsigned)STRLEN(string) + 3;  // two quotes and a trailing NUL
+    for (p = string; *p != NUL; MB_PTR_ADV(p))
+    {
+# ifdef MSWIN
+	if (double_quotes)
+	{
+	    if (*p == '"')
+		++length;		// " -> ""
+	}
+	else
+# endif
+	if (*p == '\'')
+	{
+	    if (powershell)
+		length +=2;		// ' => ''
+	    else
+		length += 3;		// ' => '\''
+	}
+	if ((*p == '\n' && (csh_like || do_newline))
+		|| (*p == '!' && (csh_like || do_special)))
+	{
+	    ++length;			// insert backslash
+	    if (csh_like && do_special)
+		++length;		// insert backslash
+	}
+	if (do_special && find_cmdline_var(p, &l) >= 0)
+	{
+	    ++length;			// insert backslash
+	    p += l - 1;
+	}
+    }
+
+    // Allocate memory for the result and fill it.
+    escaped_string = alloc(length);
+    if (escaped_string != NULL)
+    {
+	d = escaped_string;
+
+	// add opening quote
+# ifdef MSWIN
+	if (double_quotes)
+	    *d++ = '"';
+	else
+# endif
+	    *d++ = '\'';
+
+	for (p = string; *p != NUL; )
+	{
+# ifdef MSWIN
+	    if (double_quotes)
+	    {
+		if (*p == '"')
+		{
+		    *d++ = '"';
+		    *d++ = '"';
+		    ++p;
+		    continue;
+		}
+	    }
+	    else
+# endif
+	    if (*p == '\'')
+	    {
+		if (powershell)
+		{
+		    *d++ = '\'';
+		    *d++ = '\'';
+		}
+		else
+		{
+		    *d++ = '\'';
+		    *d++ = '\\';
+		    *d++ = '\'';
+		    *d++ = '\'';
+		}
+		++p;
+		continue;
+	    }
+	    if ((*p == '\n' && (csh_like || do_newline))
+		    || (*p == '!' && (csh_like || do_special)))
+	    {
+		*d++ = '\\';
+		if (csh_like && do_special)
+		    *d++ = '\\';
+		*d++ = *p++;
+		continue;
+	    }
+	    if (do_special && find_cmdline_var(p, &l) >= 0)
+	    {
+		*d++ = '\\';		// insert backslash
+		while (--l >= 0)	// copy the var
+		    *d++ = *p++;
+		continue;
+	    }
+
+	    MB_COPY_CHAR(p, d);
+	}
+
+	// add terminating quote and finish with a NUL
+# ifdef MSWIN
+	if (double_quotes)
+	    *d++ = '"';
+	else
+# endif
+	    *d++ = '\'';
+	*d = NUL;
+    }
+
+    return escaped_string;
+}
+
+/*
+ * Like vim_strsave(), but make all characters uppercase.
+ * This uses ASCII lower-to-upper case translation, language independent.
+ */
+    char_u *
+vim_strsave_up(char_u *string)
+{
+    char_u *p1;
+
+    p1 = vim_strsave(string);
+    vim_strup(p1);
+    return p1;
+}
+
+/*
+ * Like vim_strnsave(), but make all characters uppercase.
+ * This uses ASCII lower-to-upper case translation, language independent.
+ */
+    char_u *
+vim_strnsave_up(char_u *string, size_t len)
+{
+    char_u *p1;
+
+    p1 = vim_strnsave(string, len);
+    vim_strup(p1);
+    return p1;
+}
+
+/*
+ * ASCII lower-to-upper case translation, language independent.
+ */
+    void
+vim_strup(
+    char_u	*p)
+{
+    char_u  *p2;
+    int	    c;
+
+    if (p != NULL)
+    {
+	p2 = p;
+	while ((c = *p2) != NUL)
+#ifdef EBCDIC
+	    *p2++ = isalpha(c) ? toupper(c) : c;
+#else
+	    *p2++ = (c < 'a' || c > 'z') ? c : (c - 0x20);
+#endif
+    }
+}
+
+#if defined(FEAT_EVAL) || defined(FEAT_SPELL) || defined(PROTO)
+/*
+ * Make string "s" all upper-case and return it in allocated memory.
+ * Handles multi-byte characters as well as possible.
+ * Returns NULL when out of memory.
+ */
+    static char_u *
+strup_save(char_u *orig)
+{
+    char_u	*p;
+    char_u	*res;
+
+    res = p = vim_strsave(orig);
+
+    if (res != NULL)
+	while (*p != NUL)
+	{
+	    int		l;
+
+	    if (enc_utf8)
+	    {
+		int	c, uc;
+		int	newl;
+		char_u	*s;
+
+		c = utf_ptr2char(p);
+		l = utf_ptr2len(p);
+		if (c == 0)
+		{
+		    // overlong sequence, use only the first byte
+		    c = *p;
+		    l = 1;
+		}
+		uc = utf_toupper(c);
+
+		// Reallocate string when byte count changes.  This is rare,
+		// thus it's OK to do another malloc()/free().
+		newl = utf_char2len(uc);
+		if (newl != l)
+		{
+		    s = alloc(STRLEN(res) + 1 + newl - l);
+		    if (s == NULL)
+		    {
+			vim_free(res);
+			return NULL;
+		    }
+		    mch_memmove(s, res, p - res);
+		    STRCPY(s + (p - res) + newl, p + l);
+		    p = s + (p - res);
+		    vim_free(res);
+		    res = s;
+		}
+
+		utf_char2bytes(uc, p);
+		p += newl;
+	    }
+	    else if (has_mbyte && (l = (*mb_ptr2len)(p)) > 1)
+		p += l;		// skip multi-byte character
+	    else
+	    {
+		*p = TOUPPER_LOC(*p); // note that toupper() can be a macro
+		p++;
+	    }
+	}
+
+    return res;
+}
+
+/*
+ * Make string "s" all lower-case and return it in allocated memory.
+ * Handles multi-byte characters as well as possible.
+ * Returns NULL when out of memory.
+ */
+    char_u *
+strlow_save(char_u *orig)
+{
+    char_u	*p;
+    char_u	*res;
+
+    res = p = vim_strsave(orig);
+
+    if (res != NULL)
+	while (*p != NUL)
+	{
+	    int		l;
+
+	    if (enc_utf8)
+	    {
+		int	c, lc;
+		int	newl;
+		char_u	*s;
+
+		c = utf_ptr2char(p);
+		l = utf_ptr2len(p);
+		if (c == 0)
+		{
+		    // overlong sequence, use only the first byte
+		    c = *p;
+		    l = 1;
+		}
+		lc = utf_tolower(c);
+
+		// Reallocate string when byte count changes.  This is rare,
+		// thus it's OK to do another malloc()/free().
+		newl = utf_char2len(lc);
+		if (newl != l)
+		{
+		    s = alloc(STRLEN(res) + 1 + newl - l);
+		    if (s == NULL)
+		    {
+			vim_free(res);
+			return NULL;
+		    }
+		    mch_memmove(s, res, p - res);
+		    STRCPY(s + (p - res) + newl, p + l);
+		    p = s + (p - res);
+		    vim_free(res);
+		    res = s;
+		}
+
+		utf_char2bytes(lc, p);
+		p += newl;
+	    }
+	    else if (has_mbyte && (l = (*mb_ptr2len)(p)) > 1)
+		p += l;		// skip multi-byte character
+	    else
+	    {
+		*p = TOLOWER_LOC(*p); // note that tolower() can be a macro
+		p++;
+	    }
+	}
+
+    return res;
+}
+#endif
+
+/*
+ * delete spaces at the end of a string
+ */
+    void
+del_trailing_spaces(char_u *ptr)
+{
+    char_u	*q;
+
+    q = ptr + STRLEN(ptr);
+    while (--q > ptr && VIM_ISWHITE(q[0]) && q[-1] != '\\' && q[-1] != Ctrl_V)
+	*q = NUL;
+}
+
+/*
+ * Like strncpy(), but always terminate the result with one NUL.
+ * "to" must be "len + 1" long!
+ */
+    void
+vim_strncpy(char_u *to, char_u *from, size_t len)
+{
+    STRNCPY(to, from, len);
+    to[len] = NUL;
+}
+
+/*
+ * Like strcat(), but make sure the result fits in "tosize" bytes and is
+ * always NUL terminated. "from" and "to" may overlap.
+ */
+    void
+vim_strcat(char_u *to, char_u *from, size_t tosize)
+{
+    size_t tolen = STRLEN(to);
+    size_t fromlen = STRLEN(from);
+
+    if (tolen + fromlen + 1 > tosize)
+    {
+	mch_memmove(to + tolen, from, tosize - tolen - 1);
+	to[tosize - 1] = NUL;
+    }
+    else
+	mch_memmove(to + tolen, from, fromlen + 1);
+}
+
+#if (!defined(HAVE_STRCASECMP) && !defined(HAVE_STRICMP)) || defined(PROTO)
+/*
+ * Compare two strings, ignoring case, using current locale.
+ * Doesn't work for multi-byte characters.
+ * return 0 for match, < 0 for smaller, > 0 for bigger
+ */
+    int
+vim_stricmp(char *s1, char *s2)
+{
+    int		i;
+
+    for (;;)
+    {
+	i = (int)TOLOWER_LOC(*s1) - (int)TOLOWER_LOC(*s2);
+	if (i != 0)
+	    return i;			    // this character different
+	if (*s1 == NUL)
+	    break;			    // strings match until NUL
+	++s1;
+	++s2;
+    }
+    return 0;				    // strings match
+}
+#endif
+
+#if (!defined(HAVE_STRNCASECMP) && !defined(HAVE_STRNICMP)) || defined(PROTO)
+/*
+ * Compare two strings, for length "len", ignoring case, using current locale.
+ * Doesn't work for multi-byte characters.
+ * return 0 for match, < 0 for smaller, > 0 for bigger
+ */
+    int
+vim_strnicmp(char *s1, char *s2, size_t len)
+{
+    int		i;
+
+    while (len > 0)
+    {
+	i = (int)TOLOWER_LOC(*s1) - (int)TOLOWER_LOC(*s2);
+	if (i != 0)
+	    return i;			    // this character different
+	if (*s1 == NUL)
+	    break;			    // strings match until NUL
+	++s1;
+	++s2;
+	--len;
+    }
+    return 0;				    // strings match
+}
+#endif
+
+/*
+ * Search for first occurrence of "c" in "string".
+ * Version of strchr() that handles unsigned char strings with characters from
+ * 128 to 255 correctly.  It also doesn't return a pointer to the NUL at the
+ * end of the string.
+ */
+    char_u  *
+vim_strchr(char_u *string, int c)
+{
+    char_u	*p;
+    int		b;
+
+    p = string;
+    if (enc_utf8 && c >= 0x80)
+    {
+	while (*p != NUL)
+	{
+	    int l = utfc_ptr2len(p);
+
+	    // Avoid matching an illegal byte here.
+	    if (utf_ptr2char(p) == c && l > 1)
+		return p;
+	    p += l;
+	}
+	return NULL;
+    }
+    if (enc_dbcs != 0 && c > 255)
+    {
+	int	n2 = c & 0xff;
+
+	c = ((unsigned)c >> 8) & 0xff;
+	while ((b = *p) != NUL)
+	{
+	    if (b == c && p[1] == n2)
+		return p;
+	    p += (*mb_ptr2len)(p);
+	}
+	return NULL;
+    }
+    if (has_mbyte)
+    {
+	while ((b = *p) != NUL)
+	{
+	    if (b == c)
+		return p;
+	    p += (*mb_ptr2len)(p);
+	}
+	return NULL;
+    }
+    while ((b = *p) != NUL)
+    {
+	if (b == c)
+	    return p;
+	++p;
+    }
+    return NULL;
+}
+
+/*
+ * Version of strchr() that only works for bytes and handles unsigned char
+ * strings with characters above 128 correctly. It also doesn't return a
+ * pointer to the NUL at the end of the string.
+ */
+    char_u  *
+vim_strbyte(char_u *string, int c)
+{
+    char_u	*p = string;
+
+    while (*p != NUL)
+    {
+	if (*p == c)
+	    return p;
+	++p;
+    }
+    return NULL;
+}
+
+/*
+ * Search for last occurrence of "c" in "string".
+ * Version of strrchr() that handles unsigned char strings with characters from
+ * 128 to 255 correctly.  It also doesn't return a pointer to the NUL at the
+ * end of the string.
+ * Return NULL if not found.
+ * Does not handle multi-byte char for "c"!
+ */
+    char_u  *
+vim_strrchr(char_u *string, int c)
+{
+    char_u	*retval = NULL;
+    char_u	*p = string;
+
+    while (*p)
+    {
+	if (*p == c)
+	    retval = p;
+	MB_PTR_ADV(p);
+    }
+    return retval;
+}
+
+/*
+ * Vim's version of strpbrk(), in case it's missing.
+ * Don't generate a prototype for this, causes problems when it's not used.
+ */
+#ifndef PROTO
+# ifndef HAVE_STRPBRK
+#  ifdef vim_strpbrk
+#   undef vim_strpbrk
+#  endif
+    char_u *
+vim_strpbrk(char_u *s, char_u *charset)
+{
+    while (*s)
+    {
+	if (vim_strchr(charset, *s) != NULL)
+	    return s;
+	MB_PTR_ADV(s);
+    }
+    return NULL;
+}
+# endif
+#endif
+
+/*
+ * Sort an array of strings.
+ */
+static int sort_compare(const void *s1, const void *s2);
+
+    static int
+sort_compare(const void *s1, const void *s2)
+{
+    return STRCMP(*(char **)s1, *(char **)s2);
+}
+
+    void
+sort_strings(
+    char_u	**files,
+    int		count)
+{
+    qsort((void *)files, (size_t)count, sizeof(char_u *), sort_compare);
+}
+
+#if defined(FEAT_QUICKFIX) || defined(FEAT_SPELL) || defined(PROTO)
+/*
+ * Return TRUE if string "s" contains a non-ASCII character (128 or higher).
+ * When "s" is NULL FALSE is returned.
+ */
+    int
+has_non_ascii(char_u *s)
+{
+    char_u	*p;
+
+    if (s != NULL)
+	for (p = s; *p != NUL; ++p)
+	    if (*p >= 128)
+		return TRUE;
+    return FALSE;
+}
+#endif
+
+/*
+ * Concatenate two strings and return the result in allocated memory.
+ * Returns NULL when out of memory.
+ */
+    char_u  *
+concat_str(char_u *str1, char_u *str2)
+{
+    char_u  *dest;
+    size_t  l = str1 == NULL ? 0 : STRLEN(str1);
+
+    dest = alloc(l + (str2 == NULL ? 0 : STRLEN(str2)) + 1L);
+    if (dest != NULL)
+    {
+	if (str1 == NULL)
+	    *dest = NUL;
+	else
+	    STRCPY(dest, str1);
+	if (str2 != NULL)
+	    STRCPY(dest + l, str2);
+    }
+    return dest;
+}
+
+#if defined(FEAT_EVAL) || defined(PROTO)
+
+/*
+ * Return string "str" in ' quotes, doubling ' characters.
+ * If "str" is NULL an empty string is assumed.
+ * If "function" is TRUE make it function('string').
+ */
+    char_u *
+string_quote(char_u *str, int function)
+{
+    unsigned	len;
+    char_u	*p, *r, *s;
+
+    len = (function ? 13 : 3);
+    if (str != NULL)
+    {
+	len += (unsigned)STRLEN(str);
+	for (p = str; *p != NUL; MB_PTR_ADV(p))
+	    if (*p == '\'')
+		++len;
+    }
+    s = r = alloc(len);
+    if (r != NULL)
+    {
+	if (function)
+	{
+	    STRCPY(r, "function('");
+	    r += 10;
+	}
+	else
+	    *r++ = '\'';
+	if (str != NULL)
+	    for (p = str; *p != NUL; )
+	    {
+		if (*p == '\'')
+		    *r++ = '\'';
+		MB_COPY_CHAR(p, r);
+	    }
+	*r++ = '\'';
+	if (function)
+	    *r++ = ')';
+	*r++ = NUL;
+    }
+    return s;
+}
+
+    static void
+byteidx(typval_T *argvars, typval_T *rettv, int comp UNUSED)
+{
+    char_u	*t;
+    char_u	*str;
+    varnumber_T	idx;
+
+    str = tv_get_string_chk(&argvars[0]);
+    idx = tv_get_number_chk(&argvars[1], NULL);
+    rettv->vval.v_number = -1;
+    if (str == NULL || idx < 0)
+	return;
+
+    t = str;
+    for ( ; idx > 0; idx--)
+    {
+	if (*t == NUL)		// EOL reached
+	    return;
+	if (enc_utf8 && comp)
+	    t += utf_ptr2len(t);
+	else
+	    t += (*mb_ptr2len)(t);
+    }
+    rettv->vval.v_number = (varnumber_T)(t - str);
+}
+
+/*
+ * "byteidx()" function
+ */
+    void
+f_byteidx(typval_T *argvars, typval_T *rettv)
+{
+    byteidx(argvars, rettv, FALSE);
+}
+
+/*
+ * "byteidxcomp()" function
+ */
+    void
+f_byteidxcomp(typval_T *argvars, typval_T *rettv)
+{
+    byteidx(argvars, rettv, TRUE);
+}
+
+/*
+ * "charidx()" function
+ */
+    void
+f_charidx(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*str;
+    varnumber_T	idx;
+    varnumber_T	countcc = FALSE;
+    char_u	*p;
+    int		len;
+    int		(*ptr2len)(char_u *);
+
+    rettv->vval.v_number = -1;
+
+    if (argvars[0].v_type != VAR_STRING || argvars[1].v_type != VAR_NUMBER
+	    || (argvars[2].v_type != VAR_UNKNOWN
+					   && argvars[2].v_type != VAR_NUMBER
+					   && argvars[2].v_type != VAR_BOOL))
+    {
+	emsg(_(e_invarg));
+	return;
+    }
+
+    str = tv_get_string_chk(&argvars[0]);
+    idx = tv_get_number_chk(&argvars[1], NULL);
+    if (str == NULL || idx < 0)
+	return;
+
+    if (argvars[2].v_type != VAR_UNKNOWN)
+	countcc = tv_get_bool(&argvars[2]);
+    if (countcc < 0 || countcc > 1)
+    {
+	semsg(_(e_using_number_as_bool_nr), countcc);
+	return;
+    }
+
+    if (enc_utf8 && countcc)
+	ptr2len = utf_ptr2len;
+    else
+	ptr2len = mb_ptr2len;
+
+    for (p = str, len = 0; p <= str + idx; len++)
+    {
+	if (*p == NUL)
+	    return;
+	p += ptr2len(p);
+    }
+
+    rettv->vval.v_number = len > 0 ? len - 1 : 0;
+}
+
+/*
+ * "str2list()" function
+ */
+    void
+f_str2list(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*p;
+    int		utf8 = FALSE;
+
+    if (rettv_list_alloc(rettv) == FAIL)
+	return;
+
+    if (argvars[1].v_type != VAR_UNKNOWN)
+	utf8 = (int)tv_get_bool_chk(&argvars[1], NULL);
+
+    p = tv_get_string(&argvars[0]);
+
+    if (has_mbyte || utf8)
+    {
+	int (*ptr2len)(char_u *);
+	int (*ptr2char)(char_u *);
+
+	if (utf8 || enc_utf8)
+	{
+	    ptr2len = utf_ptr2len;
+	    ptr2char = utf_ptr2char;
+	}
+	else
+	{
+	    ptr2len = mb_ptr2len;
+	    ptr2char = mb_ptr2char;
+	}
+
+	for ( ; *p != NUL; p += (*ptr2len)(p))
+	    list_append_number(rettv->vval.v_list, (*ptr2char)(p));
+    }
+    else
+	for ( ; *p != NUL; ++p)
+	    list_append_number(rettv->vval.v_list, *p);
+}
+
+/*
+ * "str2nr()" function
+ */
+    void
+f_str2nr(typval_T *argvars, typval_T *rettv)
+{
+    int		base = 10;
+    char_u	*p;
+    varnumber_T	n;
+    int		what = 0;
+    int		isneg;
+
+    if (argvars[1].v_type != VAR_UNKNOWN)
+    {
+	base = (int)tv_get_number(&argvars[1]);
+	if (base != 2 && base != 8 && base != 10 && base != 16)
+	{
+	    emsg(_(e_invarg));
+	    return;
+	}
+	if (argvars[2].v_type != VAR_UNKNOWN && tv_get_bool(&argvars[2]))
+	    what |= STR2NR_QUOTE;
+    }
+
+    p = skipwhite(tv_get_string_strict(&argvars[0]));
+    isneg = (*p == '-');
+    if (*p == '+' || *p == '-')
+	p = skipwhite(p + 1);
+    switch (base)
+    {
+	case 2: what |= STR2NR_BIN + STR2NR_FORCE; break;
+	case 8: what |= STR2NR_OCT + STR2NR_OOCT + STR2NR_FORCE; break;
+	case 16: what |= STR2NR_HEX + STR2NR_FORCE; break;
+    }
+    vim_str2nr(p, NULL, NULL, what, &n, NULL, 0, FALSE);
+    // Text after the number is silently ignored.
+    if (isneg)
+	rettv->vval.v_number = -n;
+    else
+	rettv->vval.v_number = n;
+
+}
+
+/*
+ * "strgetchar()" function
+ */
+    void
+f_strgetchar(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*str;
+    int		len;
+    int		error = FALSE;
+    int		charidx;
+    int		byteidx = 0;
+
+    rettv->vval.v_number = -1;
+    str = tv_get_string_chk(&argvars[0]);
+    if (str == NULL)
+	return;
+    len = (int)STRLEN(str);
+    charidx = (int)tv_get_number_chk(&argvars[1], &error);
+    if (error)
+	return;
+
+    while (charidx >= 0 && byteidx < len)
+    {
+	if (charidx == 0)
+	{
+	    rettv->vval.v_number = mb_ptr2char(str + byteidx);
+	    break;
+	}
+	--charidx;
+	byteidx += MB_CPTR2LEN(str + byteidx);
+    }
+}
+
+/*
+ * "stridx()" function
+ */
+    void
+f_stridx(typval_T *argvars, typval_T *rettv)
+{
+    char_u	buf[NUMBUFLEN];
+    char_u	*needle;
+    char_u	*haystack;
+    char_u	*save_haystack;
+    char_u	*pos;
+    int		start_idx;
+
+    needle = tv_get_string_chk(&argvars[1]);
+    save_haystack = haystack = tv_get_string_buf_chk(&argvars[0], buf);
+    rettv->vval.v_number = -1;
+    if (needle == NULL || haystack == NULL)
+	return;		// type error; errmsg already given
+
+    if (argvars[2].v_type != VAR_UNKNOWN)
+    {
+	int	    error = FALSE;
+
+	start_idx = (int)tv_get_number_chk(&argvars[2], &error);
+	if (error || start_idx >= (int)STRLEN(haystack))
+	    return;
+	if (start_idx >= 0)
+	    haystack += start_idx;
+    }
+
+    pos	= (char_u *)strstr((char *)haystack, (char *)needle);
+    if (pos != NULL)
+	rettv->vval.v_number = (varnumber_T)(pos - save_haystack);
+}
+
+/*
+ * "string()" function
+ */
+    void
+f_string(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*tofree;
+    char_u	numbuf[NUMBUFLEN];
+
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = tv2string(&argvars[0], &tofree, numbuf,
+								get_copyID());
+    // Make a copy if we have a value but it's not in allocated memory.
+    if (rettv->vval.v_string != NULL && tofree == NULL)
+	rettv->vval.v_string = vim_strsave(rettv->vval.v_string);
+}
+
+/*
+ * "strlen()" function
+ */
+    void
+f_strlen(typval_T *argvars, typval_T *rettv)
+{
+    rettv->vval.v_number = (varnumber_T)(STRLEN(
+					      tv_get_string(&argvars[0])));
+}
+
+    static void
+strchar_common(typval_T *argvars, typval_T *rettv, int skipcc)
+{
+    char_u		*s = tv_get_string(&argvars[0]);
+    varnumber_T		len = 0;
+    int			(*func_mb_ptr2char_adv)(char_u **pp);
+
+    func_mb_ptr2char_adv = skipcc ? mb_ptr2char_adv : mb_cptr2char_adv;
+    while (*s != NUL)
+    {
+	func_mb_ptr2char_adv(&s);
+	++len;
+    }
+    rettv->vval.v_number = len;
+}
+
+/*
+ * "strcharlen()" function
+ */
+    void
+f_strcharlen(typval_T *argvars, typval_T *rettv)
+{
+    strchar_common(argvars, rettv, TRUE);
+}
+
+/*
+ * "strchars()" function
+ */
+    void
+f_strchars(typval_T *argvars, typval_T *rettv)
+{
+    varnumber_T		skipcc = FALSE;
+
+    if (argvars[1].v_type != VAR_UNKNOWN)
+	skipcc = tv_get_bool(&argvars[1]);
+    if (skipcc < 0 || skipcc > 1)
+	semsg(_(e_using_number_as_bool_nr), skipcc);
+    else
+	strchar_common(argvars, rettv, skipcc);
+}
+
+/*
+ * "strdisplaywidth()" function
+ */
+    void
+f_strdisplaywidth(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*s = tv_get_string(&argvars[0]);
+    int		col = 0;
+
+    if (argvars[1].v_type != VAR_UNKNOWN)
+	col = (int)tv_get_number(&argvars[1]);
+
+    rettv->vval.v_number = (varnumber_T)(linetabsize_col(col, s) - col);
+}
+
+/*
+ * "strwidth()" function
+ */
+    void
+f_strwidth(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*s = tv_get_string_strict(&argvars[0]);
+
+    rettv->vval.v_number = (varnumber_T)(mb_string2cells(s, -1));
+}
+
+/*
+ * "strcharpart()" function
+ */
+    void
+f_strcharpart(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*p;
+    int		nchar;
+    int		nbyte = 0;
+    int		charlen;
+    int		skipcc = FALSE;
+    int		len = 0;
+    int		slen;
+    int		error = FALSE;
+
+    p = tv_get_string(&argvars[0]);
+    slen = (int)STRLEN(p);
+
+    nchar = (int)tv_get_number_chk(&argvars[1], &error);
+    if (!error)
+    {
+	if (argvars[2].v_type != VAR_UNKNOWN
+					   && argvars[3].v_type != VAR_UNKNOWN)
+	{
+	    skipcc = tv_get_bool(&argvars[3]);
+	    if (skipcc < 0 || skipcc > 1)
+	    {
+		semsg(_(e_using_number_as_bool_nr), skipcc);
+		return;
+	    }
+	}
+
+	if (nchar > 0)
+	    while (nchar > 0 && nbyte < slen)
+	    {
+		if (skipcc)
+		    nbyte += mb_ptr2len(p + nbyte);
+		else
+		    nbyte += MB_CPTR2LEN(p + nbyte);
+		--nchar;
+	    }
+	else
+	    nbyte = nchar;
+	if (argvars[2].v_type != VAR_UNKNOWN)
+	{
+	    charlen = (int)tv_get_number(&argvars[2]);
+	    while (charlen > 0 && nbyte + len < slen)
+	    {
+		int off = nbyte + len;
+
+		if (off < 0)
+		    len += 1;
+		else
+		{
+		    if (skipcc)
+			len += mb_ptr2len(p + off);
+		    else
+			len += MB_CPTR2LEN(p + off);
+		}
+		--charlen;
+	    }
+	}
+	else
+	    len = slen - nbyte;    // default: all bytes that are available.
+    }
+
+    /*
+     * Only return the overlap between the specified part and the actual
+     * string.
+     */
+    if (nbyte < 0)
+    {
+	len += nbyte;
+	nbyte = 0;
+    }
+    else if (nbyte > slen)
+	nbyte = slen;
+    if (len < 0)
+	len = 0;
+    else if (nbyte + len > slen)
+	len = slen - nbyte;
+
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = vim_strnsave(p + nbyte, len);
+}
+
+/*
+ * "strpart()" function
+ */
+    void
+f_strpart(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*p;
+    int		n;
+    int		len;
+    int		slen;
+    int		error = FALSE;
+
+    p = tv_get_string(&argvars[0]);
+    slen = (int)STRLEN(p);
+
+    n = (int)tv_get_number_chk(&argvars[1], &error);
+    if (error)
+	len = 0;
+    else if (argvars[2].v_type != VAR_UNKNOWN)
+	len = (int)tv_get_number(&argvars[2]);
+    else
+	len = slen - n;	    // default len: all bytes that are available.
+
+    // Only return the overlap between the specified part and the actual
+    // string.
+    if (n < 0)
+    {
+	len += n;
+	n = 0;
+    }
+    else if (n > slen)
+	n = slen;
+    if (len < 0)
+	len = 0;
+    else if (n + len > slen)
+	len = slen - n;
+
+    if (argvars[2].v_type != VAR_UNKNOWN && argvars[3].v_type != VAR_UNKNOWN)
+    {
+	int off;
+
+	// length in characters
+	for (off = n; off < slen && len > 0; --len)
+	    off += mb_ptr2len(p + off);
+	len = off - n;
+    }
+
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = vim_strnsave(p + n, len);
+}
+
+/*
+ * "strridx()" function
+ */
+    void
+f_strridx(typval_T *argvars, typval_T *rettv)
+{
+    char_u	buf[NUMBUFLEN];
+    char_u	*needle;
+    char_u	*haystack;
+    char_u	*rest;
+    char_u	*lastmatch = NULL;
+    int		haystack_len, end_idx;
+
+    needle = tv_get_string_chk(&argvars[1]);
+    haystack = tv_get_string_buf_chk(&argvars[0], buf);
+
+    rettv->vval.v_number = -1;
+    if (needle == NULL || haystack == NULL)
+	return;		// type error; errmsg already given
+
+    haystack_len = (int)STRLEN(haystack);
+    if (argvars[2].v_type != VAR_UNKNOWN)
+    {
+	// Third argument: upper limit for index
+	end_idx = (int)tv_get_number_chk(&argvars[2], NULL);
+	if (end_idx < 0)
+	    return;	// can never find a match
+    }
+    else
+	end_idx = haystack_len;
+
+    if (*needle == NUL)
+    {
+	// Empty string matches past the end.
+	lastmatch = haystack + end_idx;
+    }
+    else
+    {
+	for (rest = haystack; *rest != '\0'; ++rest)
+	{
+	    rest = (char_u *)strstr((char *)rest, (char *)needle);
+	    if (rest == NULL || rest > haystack + end_idx)
+		break;
+	    lastmatch = rest;
+	}
+    }
+
+    if (lastmatch == NULL)
+	rettv->vval.v_number = -1;
+    else
+	rettv->vval.v_number = (varnumber_T)(lastmatch - haystack);
+}
+
+/*
+ * "strtrans()" function
+ */
+    void
+f_strtrans(typval_T *argvars, typval_T *rettv)
+{
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = transstr(tv_get_string(&argvars[0]));
+}
+
+/*
+ * "tolower(string)" function
+ */
+    void
+f_tolower(typval_T *argvars, typval_T *rettv)
+{
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = strlow_save(tv_get_string(&argvars[0]));
+}
+
+/*
+ * "toupper(string)" function
+ */
+    void
+f_toupper(typval_T *argvars, typval_T *rettv)
+{
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = strup_save(tv_get_string(&argvars[0]));
+}
+
+/*
+ * "tr(string, fromstr, tostr)" function
+ */
+    void
+f_tr(typval_T *argvars, typval_T *rettv)
+{
+    char_u	*in_str;
+    char_u	*fromstr;
+    char_u	*tostr;
+    char_u	*p;
+    int		inlen;
+    int		fromlen;
+    int		tolen;
+    int		idx;
+    char_u	*cpstr;
+    int		cplen;
+    int		first = TRUE;
+    char_u	buf[NUMBUFLEN];
+    char_u	buf2[NUMBUFLEN];
+    garray_T	ga;
+
+    in_str = tv_get_string(&argvars[0]);
+    fromstr = tv_get_string_buf_chk(&argvars[1], buf);
+    tostr = tv_get_string_buf_chk(&argvars[2], buf2);
+
+    // Default return value: empty string.
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = NULL;
+    if (fromstr == NULL || tostr == NULL)
+	    return;		// type error; errmsg already given
+    ga_init2(&ga, (int)sizeof(char), 80);
+
+    if (!has_mbyte)
+	// not multi-byte: fromstr and tostr must be the same length
+	if (STRLEN(fromstr) != STRLEN(tostr))
+	{
+error:
+	    semsg(_(e_invarg2), fromstr);
+	    ga_clear(&ga);
+	    return;
+	}
+
+    // fromstr and tostr have to contain the same number of chars
+    while (*in_str != NUL)
+    {
+	if (has_mbyte)
+	{
+	    inlen = (*mb_ptr2len)(in_str);
+	    cpstr = in_str;
+	    cplen = inlen;
+	    idx = 0;
+	    for (p = fromstr; *p != NUL; p += fromlen)
+	    {
+		fromlen = (*mb_ptr2len)(p);
+		if (fromlen == inlen && STRNCMP(in_str, p, inlen) == 0)
+		{
+		    for (p = tostr; *p != NUL; p += tolen)
+		    {
+			tolen = (*mb_ptr2len)(p);
+			if (idx-- == 0)
+			{
+			    cplen = tolen;
+			    cpstr = p;
+			    break;
+			}
+		    }
+		    if (*p == NUL)	// tostr is shorter than fromstr
+			goto error;
+		    break;
+		}
+		++idx;
+	    }
+
+	    if (first && cpstr == in_str)
+	    {
+		// Check that fromstr and tostr have the same number of
+		// (multi-byte) characters.  Done only once when a character
+		// of in_str doesn't appear in fromstr.
+		first = FALSE;
+		for (p = tostr; *p != NUL; p += tolen)
+		{
+		    tolen = (*mb_ptr2len)(p);
+		    --idx;
+		}
+		if (idx != 0)
+		    goto error;
+	    }
+
+	    (void)ga_grow(&ga, cplen);
+	    mch_memmove((char *)ga.ga_data + ga.ga_len, cpstr, (size_t)cplen);
+	    ga.ga_len += cplen;
+
+	    in_str += inlen;
+	}
+	else
+	{
+	    // When not using multi-byte chars we can do it faster.
+	    p = vim_strchr(fromstr, *in_str);
+	    if (p != NULL)
+		ga_append(&ga, tostr[p - fromstr]);
+	    else
+		ga_append(&ga, *in_str);
+	    ++in_str;
+	}
+    }
+
+    // add a terminating NUL
+    (void)ga_grow(&ga, 1);
+    ga_append(&ga, NUL);
+
+    rettv->vval.v_string = ga.ga_data;
+}
+
+/*
+ * "trim({expr})" function
+ */
+    void
+f_trim(typval_T *argvars, typval_T *rettv)
+{
+    char_u	buf1[NUMBUFLEN];
+    char_u	buf2[NUMBUFLEN];
+    char_u	*head = tv_get_string_buf_chk(&argvars[0], buf1);
+    char_u	*mask = NULL;
+    char_u	*tail;
+    char_u	*prev;
+    char_u	*p;
+    int		c1;
+    int		dir = 0;
+
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = NULL;
+    if (head == NULL)
+	return;
+
+    if (argvars[1].v_type != VAR_UNKNOWN && argvars[1].v_type != VAR_STRING)
+    {
+	semsg(_(e_invarg2), tv_get_string(&argvars[1]));
+	return;
+    }
+
+    if (argvars[1].v_type == VAR_STRING)
+    {
+	mask = tv_get_string_buf_chk(&argvars[1], buf2);
+
+	if (argvars[2].v_type != VAR_UNKNOWN)
+	{
+	    int	error = 0;
+
+	    // leading or trailing characters to trim
+	    dir = (int)tv_get_number_chk(&argvars[2], &error);
+	    if (error)
+		return;
+	    if (dir < 0 || dir > 2)
+	    {
+		semsg(_(e_invarg2), tv_get_string(&argvars[2]));
+		return;
+	    }
+	}
+    }
+
+    if (dir == 0 || dir == 1)
+    {
+	// Trim leading characters
+	while (*head != NUL)
+	{
+	    c1 = PTR2CHAR(head);
+	    if (mask == NULL)
+	    {
+		if (c1 > ' ' && c1 != 0xa0)
+		    break;
+	    }
+	    else
+	    {
+		for (p = mask; *p != NUL; MB_PTR_ADV(p))
+		    if (c1 == PTR2CHAR(p))
+			break;
+		if (*p == NUL)
+		    break;
+	    }
+	    MB_PTR_ADV(head);
+	}
+    }
+
+    tail = head + STRLEN(head);
+    if (dir == 0 || dir == 2)
+    {
+	// Trim trailing characters
+	for (; tail > head; tail = prev)
+	{
+	    prev = tail;
+	    MB_PTR_BACK(head, prev);
+	    c1 = PTR2CHAR(prev);
+	    if (mask == NULL)
+	    {
+		if (c1 > ' ' && c1 != 0xa0)
+		    break;
+	    }
+	    else
+	    {
+		for (p = mask; *p != NUL; MB_PTR_ADV(p))
+		    if (c1 == PTR2CHAR(p))
+			break;
+		if (*p == NUL)
+		    break;
+	    }
+	}
+    }
+    rettv->vval.v_string = vim_strnsave(head, tail - head);
+}
+
+#endif