new file mode 100644
--- /dev/null
+++ b/src/spell.c
@@ -0,0 +1,702 @@
+/* vi:set ts=8 sts=4 sw=4:
+ *
+ * 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.
+ */
+
+/*
+ * spell.c: code for spell checking
+ */
+
+#if defined(MSDOS) || defined(WIN16) || defined(WIN32) || defined(_WIN64)
+# include <io.h>	/* for lseek(), must be before vim.h */
+#endif
+
+#include "vim.h"
+
+#if defined(FEAT_SYN_HL) || defined(PROTO)
+
+#ifdef HAVE_FCNTL_H
+# include <fcntl.h>
+#endif
+
+/*
+ * Structure that is used to store the text from the language file.  This
+ * avoids the need to allocate each individual word and copying it.  It's
+ * allocated in big chunks for speed.
+ */
+#define  SBLOCKSIZE 4096	/* default size of sb_data */
+typedef struct sblock_S sblock_T;
+struct sblock_S
+{
+    sblock_T	*sb_next;	/* next block in list */
+    char_u	sb_data[1];	/* data, actually longer */
+};
+
+/*
+ * Structure used to store words and other info for one language.
+ */
+typedef struct slang_S slang_T;
+
+struct slang_S
+{
+    slang_T	*sl_next;	/* next language */
+    char_u	sl_name[2];	/* language name "en", "nl", etc. */
+    hashtab_T	sl_ht;		/* hashtable with all words */
+    garray_T	sl_match;	/* table with pointers to matches */
+    garray_T	sl_add;		/* table with pointers to additions */
+    char_u	sl_regions[13];	/* table with up to 6 region names */
+    sblock_T	*sl_block;	/* list with allocated memory blocks */
+};
+
+static slang_T *first_lang = NULL;
+
+/*
+ * Structure used in "b_langp", filled from 'spelllang'.
+ */
+typedef struct langp_S
+{
+    slang_T	*lp_slang;	/* info for this language (NULL for last one) */
+    int		lp_region;	/* bitmask for region or REGION_ALL */
+} langp_T;
+
+#define LANGP_ENTRY(ga, i)	(((langp_T *)(ga).ga_data) + (i))
+#define MATCH_ENTRY(gap, i)	*(((char_u **)(gap)->ga_data) + i)
+
+/*
+ * The byte before a word in the hashtable indicates the type of word.
+ * Also used for the byte just before a match.
+ * The top two bits are used to indicate rare and case-sensitive words.
+ * The lower bits are used to indicate the region in which the word is valid.
+ * Words valid in all regions use REGION_ALL.
+ */
+#define REGION_MASK	0x3f
+#define REGION_ALL	0x3f
+#define CASE_MASK	0x40
+#define RARE_MASK	0x80
+
+#define SP_OK		0
+#define SP_BAD		1
+#define SP_RARE		2
+#define SP_LOCAL	3
+
+static slang_T *spell_load_lang __ARGS((char_u *lang));
+static void spell_load_file __ARGS((char_u *fname));
+static int find_region __ARGS((char_u *rp, char_u *region));
+
+/*
+ * Main spell-checking function.
+ * "ptr" points to the start of a word.
+ * "*attrp" is set to the attributes for a badly spelled word.  For a non-word
+ * or when it's OK it remains unchanged.
+ * This must only be called when 'spelllang' is not empty.
+ * Returns the length of the word in bytes, also when it's OK, so that the
+ * caller can skip over the word.
+ */
+    int
+spell_check(wp, ptr, attrp)
+    win_T	*wp;		/* current window */
+    char_u	*ptr;
+    int		*attrp;
+{
+    char_u	*e;
+    langp_T	*lp;
+    int		result;
+    int		len = 0;
+    hash_T	hash;
+    hashitem_T	*hi;
+    int		c;
+#define MAXWLEN 80	/* assume max. word len is 80 */
+    char_u	word[MAXWLEN + 1];
+    garray_T	*gap;
+    int		l, h, t;
+    char_u	*p;
+    int		n;
+
+    /* Find the end of the word.  We already know that *ptr is a word char. */
+    e = ptr;
+    do
+    {
+	mb_ptr_adv(e);
+	++len;
+    } while (*e != NUL && vim_iswordc_buf(e, wp->w_buffer));
+
+    /* The word is bad unless we find it in the dictionary. */
+    result = SP_BAD;
+
+    /* Words are always stored with folded case. */
+    (void)str_foldcase(ptr, e - ptr, word, MAXWLEN + 1);
+    hash = hash_hash(word);
+
+    /*
+     * Loop over the languages specified in 'spelllang'.
+     * We check them all, because a match may find a longer word.
+     */
+    for (lp = LANGP_ENTRY(wp->w_buffer->b_langp, 0); lp->lp_slang != NULL;
+								     ++lp)
+    {
+	/* Check words when it wasn't recognized as a good word yet. */
+	if (result != SP_OK)
+	{
+	    /* Word lookup.  Using a hash table is fast. */
+	    hi = hash_lookup(&lp->lp_slang->sl_ht, word, hash);
+	    if (!HASHITEM_EMPTY(hi))
+	    {
+		/* The character before the key indicates the type of word. */
+		c = hi->hi_key[-1];
+		if ((c & CASE_MASK) != 0)
+		{
+		    /* Need to check first letter is uppercase.  If it is,
+		     * check region.  If it isn't it may be a rare word. */
+		    if (
+#ifdef FEAT_MBYTE
+			    MB_ISUPPER(mb_ptr2char(ptr))
+#else
+			    MB_ISUPPER(*ptr)
+#endif
+			    )
+		    {
+			if ((c & lp->lp_region) == 0)
+			    result = SP_LOCAL;
+			else
+			    result = SP_OK;
+		    }
+		    else if (c & RARE_MASK)
+			result = SP_RARE;
+		}
+		else
+		{
+		    if ((c & lp->lp_region) == 0)
+			result = SP_LOCAL;
+		    else if (c & RARE_MASK)
+			result = SP_RARE;
+		    else
+			result = SP_OK;
+		}
+	    }
+	}
+
+	/* Match lookup.  Uses a binary search.  If there is a match adjust
+	 * "e" to the end.  This is also done when a word matched, because
+	 * "you've" is longer than "you". */
+	gap = &lp->lp_slang->sl_match;
+	l = 0;			/* low index */
+	h = gap->ga_len - 1;	/* high index */
+	/* keep searching, the match must be between "l" and "h" (inclusive) */
+	while (h >= l)
+	{
+	    t = (h + l) / 2;
+	    p = MATCH_ENTRY(gap, t) + 1;
+	    for (n = 0; p[n] != 0 && p[n] == ptr[n]; ++n)
+		;
+	    if (p[n] == 0)
+	    {
+		if ((ptr[n] == 0 || !vim_iswordc_buf(ptr + n, wp->w_buffer)))
+		{
+		    /* match! */
+		    e = ptr + n;
+		    if (result != SP_OK)
+		    {
+			if ((lp->lp_region & p[-1]) == 0)
+			    result = SP_LOCAL;
+			else
+			    result = SP_OK;
+		    }
+		    break;
+		}
+		/* match is too short, next item is new low index */
+		l = t + 1;
+	    }
+	    else if (p[n] < ptr[n])
+		/* match is before word, next item is new low index */
+		l = t + 1;
+	    else
+		/* match is after word, previous item is new high index */
+		h = t - 1;
+	}
+
+	/* Addition lookup.  Uses a linear search, there should be very few.
+	 * If there is a match adjust "e" to the end.  This doesn't change
+	 * whether a word was good or bad, only the length. */
+	gap = &lp->lp_slang->sl_add;
+	for (t = 0; t < gap->ga_len; ++t)
+	{
+	    p = MATCH_ENTRY(gap, t) + 1;
+	    for (n = 0; p[n] != 0 && p[n] == e[n]; ++n)
+		;
+	    if (p[n] == 0
+		      && (e[n] == 0 || !vim_iswordc_buf(e + n, wp->w_buffer)))
+	    {
+		/* match */
+		e += n;
+		break;
+	    }
+	}
+    }
+
+    if (result != SP_OK)
+    {
+	if (result == SP_BAD)
+	    *attrp = highlight_attr[HLF_SPB];
+	else if (result == SP_RARE)
+	    *attrp = highlight_attr[HLF_SPR];
+	else
+	    *attrp = highlight_attr[HLF_SPL];
+    }
+
+    return (int)(e - ptr);
+}
+
+static slang_T	    *load_lp;	/* passed from spell_load_lang() to
+				   spell_load_file() */
+
+/*
+ * Load language "lang[2]".
+ */
+    static slang_T *
+spell_load_lang(lang)
+    char_u	*lang;
+{
+    slang_T	*lp;
+    char_u	fname_enc[80];
+    char_u	fname_ascii[20];
+    char_u	*p;
+
+    lp = (slang_T *)alloc(sizeof(slang_T));
+    if (lp != NULL)
+    {
+	lp->sl_name[0] = lang[0];
+	lp->sl_name[1] = lang[1];
+	hash_init(&lp->sl_ht);
+	ga_init2(&lp->sl_match, sizeof(char_u *), 20);
+	ga_init2(&lp->sl_add, sizeof(char_u *), 4);
+	lp->sl_regions[0] = NUL;
+	lp->sl_block = NULL;
+
+	/* Find all spell files for "lang" in 'runtimepath' and load them.
+	 * Use 'encoding', except that we use "latin1" for "latin9". */
+#ifdef FEAT_MBYTE
+	if (STRLEN(p_enc) < 60 && STRCMP(p_enc, "iso-8859-15") != 0)
+	    p = p_enc;
+	else
+#endif
+	    p = (char_u *)"latin1";
+	load_lp = lp;
+	sprintf((char *)fname_enc, "spell/%c%c.%s.spl", lang[0], lang[1], p);
+	if (do_in_runtimepath(fname_enc, TRUE, spell_load_file) == FAIL)
+	{
+	    /* Try again to find an ASCII spell file. */
+	    sprintf((char *)fname_ascii, "spell/%c%c.spl", lang[0], lang[1]);
+	    if (do_in_runtimepath(fname_ascii, TRUE, spell_load_file) == FAIL)
+	    {
+		vim_free(lp);
+		lp = NULL;
+		smsg((char_u *)_("Warning: Cannot find dictionary \"%s\""),
+							       fname_enc + 6);
+	    }
+	}
+	else
+	{
+	    lp->sl_next = first_lang;
+	    first_lang = lp;
+	}
+    }
+
+    return lp;
+}
+
+/*
+ * Load one spell file into "load_lp".
+ * Invoked through do_in_runtimepath().
+ */
+    static void
+spell_load_file(fname)
+    char_u	*fname;
+{
+    int		fd;
+    size_t	len;
+    size_t	l;
+    size_t	rest = 0;
+    char_u	*p = NULL, *np;
+    sblock_T	*bl;
+    hash_T	hash;
+    hashitem_T	*hi;
+    int		c;
+    int		region = REGION_ALL;
+    char_u	word[MAXWLEN + 1];
+    int		n;
+
+    fd = mch_open((char *)fname, O_RDONLY | O_EXTRA, 0);
+    if (fd < 0)
+    {
+	EMSG2(_(e_notopen), fname);
+	return;
+    }
+
+    /* Get the length of the whole file. */
+    len = lseek(fd, (off_t)0, SEEK_END);
+    lseek(fd, (off_t)0, SEEK_SET);
+
+    /* Loop, reading the file one block at a time.
+     * "rest" is the length of an incomplete line at the previous block.
+     * "p" points to the remainder. */
+    while (len > 0)
+    {
+	/* Allocate a block of memory to store the info in.  This is not freed
+	 * until spell_reload() is called. */
+	if (len > SBLOCKSIZE)
+	    l = SBLOCKSIZE;
+	else
+	    l = len;
+	len -= l;
+	bl = (sblock_T *)alloc((unsigned)(sizeof(sblock_T) - 1 + l + rest));
+	if (bl == NULL)
+	    break;
+	bl->sb_next = load_lp->sl_block;
+	load_lp->sl_block = bl;
+
+	/* Read a block from the file.  Prepend the remainder of the previous
+	 * block. */
+	if (rest > 0)
+	    mch_memmove(bl->sb_data, p, rest);
+	if (read(fd, bl->sb_data + rest, l) != l)
+	{
+	    EMSG2(_(e_notread), fname);
+	    break;
+	}
+	l += rest;
+	rest = 0;
+
+	/* Deal with each line that was read until we finish the block. */
+	for (p = bl->sb_data; l > 0; p = np)
+	{
+	    /* "np" points to the char after the line (CR or NL). */
+	    for (np = p; l > 0 && *np >= ' '; ++np)
+		--l;
+	    if (l == 0)
+	    {
+		/* Incomplete line (or end of file). */
+		rest = np - p;
+		if (len == 0)
+		    EMSG2(_("E751: Truncated spell file: %s"), fname);
+		break;
+	    }
+	    *np = NUL;	    /* terminate the line with a NUL */
+
+	    /* Skip comment and empty lines. */
+	    c = *p;
+	    if (c != '#' && np > p)
+	    {
+		if (c == '=' || c == '+')
+		{
+		    garray_T *gap;
+
+		    /* Match or Add item. */
+		    if (c == '=')
+			gap = &load_lp->sl_match;
+		    else
+			gap = &load_lp->sl_add;
+
+		    if (ga_grow(gap, 1) == OK)
+		    {
+			for (n = 0; n < gap->ga_len; ++n)
+			    if ((c = STRCMP(p + 1,
+						MATCH_ENTRY(gap, n) + 1)) < 0)
+				break;
+			if (c == 0)
+			{
+			    if (p_verbose > 0)
+				smsg((char_u *)_("Warning: duplicate match \"%s\" in %s"),
+								p + 1, fname);
+			}
+			else
+			{
+			    mch_memmove((char_u **)gap->ga_data + n + 1,
+				    (char_u **)gap->ga_data + n,
+				    (gap->ga_len - n) * sizeof(char_u *));
+			    *(((char_u **)gap->ga_data) + n) = p;
+			    *p = region;
+			    ++gap->ga_len;
+			}
+		    }
+		}
+		else if (c == '-')
+		{
+		    /* region item */
+		    ++p;
+		    if (*p == '-')
+			/* end of a region */
+			region = REGION_ALL;
+		    else
+		    {
+			char_u	*rp = load_lp->sl_regions;
+			int	r;
+
+			/* The region may be repeated: "-ca-uk".  Fill
+			 * "region" with the bit mask for the ones we find. */
+			region = 0;
+			for (;;)
+			{
+			    /* start of a region */
+			    r = find_region(rp, p);
+			    if (r == REGION_ALL)
+			    {
+				/* new region, add it */
+				r = STRLEN(rp);
+				if (r >= 12)
+				{
+				    EMSG2(_("E752: Too many regions in %s"),
+								       fname);
+				    r = REGION_ALL;
+				}
+				else
+				{
+				    rp[r] = p[0];
+				    rp[r + 1] = p[1];
+				    rp[r + 2] = NUL;
+				    r = 1 << (r / 2);
+				}
+			    }
+			    else
+				r = 1 << r;
+
+			    region |= r;
+			    if (p[2] != '-')
+			    {
+				if (p[2] != NUL)
+				    EMSG2(_("E753: Invalid character in \"%s\""),
+								       p - 1);
+				break;
+			    }
+			    p += 3;
+			}
+		    }
+		}
+		else
+		{
+		    /* add the word */
+		    if (c == '>')
+			c = region | RARE_MASK;
+		    else
+		    {
+			if (c != ' ')
+			    EMSG2(_("E753: Invalid character in \"%s\""), p);
+			c = region;
+		    }
+#ifdef FEAT_MBYTE
+		    if (MB_ISUPPER(mb_ptr2char(p + 1)))
+#else
+		    if (MB_ISUPPER(p[1]))
+#endif
+			c |= CASE_MASK;
+		    *p++ = c;
+		    (void)str_foldcase(p, np - p, word, MAXWLEN + 1);
+		    n = STRLEN(word);
+		    if (n > np - p)
+		    {
+			sblock_T	*s;
+
+			/* Folding case made word longer!  We need to allocate
+			 * memory for it. */
+			s = (sblock_T *)alloc((unsigned)sizeof(sblock_T)
+								     + n + 1);
+			if (s != NULL)
+			{
+			    s->sb_next = load_lp->sl_block;
+			    load_lp->sl_block = s;
+			    s->sb_data[0] = p[-1];
+			    p = s->sb_data + 1;
+			}
+		    }
+		    mch_memmove(p, word, n + 1);
+
+		    hash = hash_hash(p);
+		    hi = hash_lookup(&load_lp->sl_ht, p, hash);
+		    if (!HASHITEM_EMPTY(hi))
+		    {
+			c = hi->hi_key[-1];
+			if ((c & (CASE_MASK | RARE_MASK))
+					 == (p[-1] & (CASE_MASK | RARE_MASK)))
+			{
+			    if (p_verbose > 0)
+				smsg((char_u *)_("Warning: duplicate word \"%s\" in %s"),
+								    p, fname);
+			}
+			else
+			    hi->hi_key[-1] |= (p[-1] & (CASE_MASK | RARE_MASK));
+		    }
+		    else
+			hash_add_item(&load_lp->sl_ht, hi, p, hash);
+		}
+	    }
+
+	    while (l > 0 && *np < ' ')
+	    {
+		++np;
+		--l;
+	    }
+	}
+    }
+
+    close(fd);
+}
+
+/*
+ * Parse 'spelllang' and set buf->b_langp accordingly.
+ * Returns an error message or NULL.
+ */
+    char_u *
+did_set_spelllang(buf)
+    buf_T	*buf;
+{
+    garray_T	ga;
+    char_u	*lang;
+    char_u	*e;
+    char_u	*region;
+    int		region_mask;
+    slang_T	*lp;
+    int		c;
+
+    ga_init2(&ga, sizeof(langp_T), 2);
+
+    /* loop over comma separated languages. */
+    for (lang = buf->b_p_spl; *lang != NUL; lang = e)
+    {
+	e = vim_strchr(lang, ',');
+	if (e == NULL)
+	    e = lang + STRLEN(lang);
+	if (e > lang + 2)
+	{
+	    if (lang[2] != '_' || e - lang != 5)
+	    {
+		ga_clear(&ga);
+		return e_invarg;
+	    }
+	    region = lang + 3;
+	}
+	else
+	    region = NULL;
+
+	for (lp = first_lang; lp != NULL; lp = lp->sl_next)
+	    if (STRNICMP(lp->sl_name, lang, 2) == 0)
+		break;
+
+	if (lp == NULL)
+	    /* Not found, load the language. */
+	    lp = spell_load_lang(lang);
+
+	if (lp != NULL)
+	{
+	    if (region == NULL)
+		region_mask = REGION_ALL;
+	    else
+	    {
+		/* find region in sl_regions */
+		c = find_region(lp->sl_regions, region);
+		if (c == REGION_ALL)
+		{
+		    c = lang[5];
+		    lang[5] = NUL;
+		    smsg((char_u *)_("Warning: region %s not supported"), lang);
+		    lang[5] = c;
+		    region_mask = REGION_ALL;
+		}
+		else
+		    region_mask = 1 << c;
+	    }
+
+	    if (ga_grow(&ga, 1) == FAIL)
+	    {
+		ga_clear(&ga);
+		return e_outofmem;
+	    }
+	    LANGP_ENTRY(ga, ga.ga_len)->lp_slang = lp;
+	    LANGP_ENTRY(ga, ga.ga_len)->lp_region = region_mask;
+	    ++ga.ga_len;
+	}
+
+	if (*e == ',')
+	    ++e;
+    }
+
+    /* Add a NULL entry to mark the end of the list. */
+    if (ga_grow(&ga, 1) == FAIL)
+    {
+	ga_clear(&ga);
+	return e_outofmem;
+    }
+    LANGP_ENTRY(ga, ga.ga_len)->lp_slang = NULL;
+    ++ga.ga_len;
+
+    /* Everything is fine, store the new b_langp value. */
+    ga_clear(&buf->b_langp);
+    buf->b_langp = ga;
+
+    return NULL;
+}
+
+/*
+ * Find the region "region[2]" in "rp" (points to "sl_regions").
+ * Each region is simply stored as the two characters of it's name.
+ * Returns the index if found, REGION_ALL if not found.
+ */
+    static int
+find_region(rp, region)
+    char_u	*rp;
+    char_u	*region;
+{
+    int		i;
+
+    for (i = 0; ; i += 2)
+    {
+	if (rp[i] == NUL)
+	    return REGION_ALL;
+	if (rp[i] == region[0] && rp[i + 1] == region[1])
+	    break;
+    }
+    return i / 2;
+}
+
+# if defined(FEAT_MBYTE) || defined(PROTO)
+/*
+ * Clear all spelling tables and reload them.
+ * Used after 'encoding' is set.
+ */
+    void
+spell_reload()
+{
+    buf_T	*buf;
+    slang_T	*lp;
+    sblock_T	*sp;
+
+    /* Unload all allocated memory. */
+    while (first_lang != NULL)
+    {
+	lp = first_lang;
+	first_lang = lp->sl_next;
+
+	hash_clear(&lp->sl_ht);
+	ga_clear(&lp->sl_match);
+	ga_clear(&lp->sl_add);
+	while (lp->sl_block != NULL)
+	{
+	    sp = lp->sl_block;
+	    lp->sl_block = sp->sb_next;
+	    vim_free(sp);
+	}
+    }
+
+    /* Go through all buffers and handle 'spelllang'. */
+    for (buf = firstbuf; buf != NULL; buf = buf->b_next)
+    {
+	ga_clear(&buf->b_langp);
+	if (*buf->b_p_spl != NUL)
+	    did_set_spelllang(buf);
+    }
+}
+# endif
+
+#endif  /* FEAT_SYN_HL */