--- a/src/viminfo.c
+++ b/src/viminfo.c
@@ -169,6 +169,493 @@ write_viminfo_bufferlist(FILE *fp)
     vim_free(line);
 }
 
+#if defined(FEAT_CMDHIST) || defined(PROTO)
+/*
+ * Buffers for history read from a viminfo file.  Only valid while reading.
+ */
+static histentry_T *viminfo_history[HIST_COUNT] =
+					       {NULL, NULL, NULL, NULL, NULL};
+static int	viminfo_hisidx[HIST_COUNT] = {0, 0, 0, 0, 0};
+static int	viminfo_hislen[HIST_COUNT] = {0, 0, 0, 0, 0};
+static int	viminfo_add_at_front = FALSE;
+
+/*
+ * Translate a history type number to the associated character.
+ */
+    static int
+hist_type2char(
+    int	    type,
+    int	    use_question)	    // use '?' instead of '/'
+{
+    if (type == HIST_CMD)
+	return ':';
+    if (type == HIST_SEARCH)
+    {
+	if (use_question)
+	    return '?';
+	else
+	    return '/';
+    }
+    if (type == HIST_EXPR)
+	return '=';
+    return '@';
+}
+
+/*
+ * Prepare for reading the history from the viminfo file.
+ * This allocates history arrays to store the read history lines.
+ */
+    static void
+prepare_viminfo_history(int asklen, int writing)
+{
+    int	    i;
+    int	    num;
+    int	    type;
+    int	    len;
+    int	    hislen = get_hislen();
+
+    init_history();
+    viminfo_add_at_front = (asklen != 0 && !writing);
+    if (asklen > hislen)
+	asklen = hislen;
+
+    for (type = 0; type < HIST_COUNT; ++type)
+    {
+	histentry_T *histentry = get_histentry(type);
+
+	// Count the number of empty spaces in the history list.  Entries read
+	// from viminfo previously are also considered empty.  If there are
+	// more spaces available than we request, then fill them up.
+	for (i = 0, num = 0; i < hislen; i++)
+	    if (histentry[i].hisstr == NULL || histentry[i].viminfo)
+		num++;
+	len = asklen;
+	if (num > len)
+	    len = num;
+	if (len <= 0)
+	    viminfo_history[type] = NULL;
+	else
+	    viminfo_history[type] = LALLOC_MULT(histentry_T, len);
+	if (viminfo_history[type] == NULL)
+	    len = 0;
+	viminfo_hislen[type] = len;
+	viminfo_hisidx[type] = 0;
+    }
+}
+
+/*
+ * Accept a line from the viminfo, store it in the history array when it's
+ * new.
+ */
+    static int
+read_viminfo_history(vir_T *virp, int writing)
+{
+    int		type;
+    long_u	len;
+    char_u	*val;
+    char_u	*p;
+
+    type = hist_char2type(virp->vir_line[0]);
+    if (viminfo_hisidx[type] < viminfo_hislen[type])
+    {
+	val = viminfo_readstring(virp, 1, TRUE);
+	if (val != NULL && *val != NUL)
+	{
+	    int sep = (*val == ' ' ? NUL : *val);
+
+	    if (!in_history(type, val + (type == HIST_SEARCH),
+					  viminfo_add_at_front, sep, writing))
+	    {
+		// Need to re-allocate to append the separator byte.
+		len = STRLEN(val);
+		p = alloc(len + 2);
+		if (p != NULL)
+		{
+		    if (type == HIST_SEARCH)
+		    {
+			// Search entry: Move the separator from the first
+			// column to after the NUL.
+			mch_memmove(p, val + 1, (size_t)len);
+			p[len] = sep;
+		    }
+		    else
+		    {
+			// Not a search entry: No separator in the viminfo
+			// file, add a NUL separator.
+			mch_memmove(p, val, (size_t)len + 1);
+			p[len + 1] = NUL;
+		    }
+		    viminfo_history[type][viminfo_hisidx[type]].hisstr = p;
+		    viminfo_history[type][viminfo_hisidx[type]].time_set = 0;
+		    viminfo_history[type][viminfo_hisidx[type]].viminfo = TRUE;
+		    viminfo_history[type][viminfo_hisidx[type]].hisnum = 0;
+		    viminfo_hisidx[type]++;
+		}
+	    }
+	}
+	vim_free(val);
+    }
+    return viminfo_readline(virp);
+}
+
+/*
+ * Accept a new style history line from the viminfo, store it in the history
+ * array when it's new.
+ */
+    static void
+handle_viminfo_history(
+	garray_T    *values,
+	int	    writing)
+{
+    int		type;
+    long_u	len;
+    char_u	*val;
+    char_u	*p;
+    bval_T	*vp = (bval_T *)values->ga_data;
+
+    // Check the format:
+    // |{bartype},{histtype},{timestamp},{separator},"text"
+    if (values->ga_len < 4
+	    || vp[0].bv_type != BVAL_NR
+	    || vp[1].bv_type != BVAL_NR
+	    || (vp[2].bv_type != BVAL_NR && vp[2].bv_type != BVAL_EMPTY)
+	    || vp[3].bv_type != BVAL_STRING)
+	return;
+
+    type = vp[0].bv_nr;
+    if (type >= HIST_COUNT)
+	return;
+    if (viminfo_hisidx[type] < viminfo_hislen[type])
+    {
+	val = vp[3].bv_string;
+	if (val != NULL && *val != NUL)
+	{
+	    int sep = type == HIST_SEARCH && vp[2].bv_type == BVAL_NR
+						      ? vp[2].bv_nr : NUL;
+	    int idx;
+	    int overwrite = FALSE;
+
+	    if (!in_history(type, val, viminfo_add_at_front, sep, writing))
+	    {
+		// If lines were written by an older Vim we need to avoid
+		// getting duplicates. See if the entry already exists.
+		for (idx = 0; idx < viminfo_hisidx[type]; ++idx)
+		{
+		    p = viminfo_history[type][idx].hisstr;
+		    if (STRCMP(val, p) == 0
+			  && (type != HIST_SEARCH || sep == p[STRLEN(p) + 1]))
+		    {
+			overwrite = TRUE;
+			break;
+		    }
+		}
+
+		if (!overwrite)
+		{
+		    // Need to re-allocate to append the separator byte.
+		    len = vp[3].bv_len;
+		    p = alloc(len + 2);
+		}
+		else
+		    len = 0; // for picky compilers
+		if (p != NULL)
+		{
+		    viminfo_history[type][idx].time_set = vp[1].bv_nr;
+		    if (!overwrite)
+		    {
+			mch_memmove(p, val, (size_t)len + 1);
+			// Put the separator after the NUL.
+			p[len + 1] = sep;
+			viminfo_history[type][idx].hisstr = p;
+			viminfo_history[type][idx].hisnum = 0;
+			viminfo_history[type][idx].viminfo = TRUE;
+			viminfo_hisidx[type]++;
+		    }
+		}
+	    }
+	}
+    }
+}
+
+/*
+ * Concatenate history lines from viminfo after the lines typed in this Vim.
+ */
+    static void
+concat_history(int type)
+{
+    int		idx;
+    int		i;
+    int		hislen = get_hislen();
+    histentry_T *histentry = get_histentry(type);
+    int		*hisidx = get_hisidx(type);
+    int		*hisnum = get_hisnum(type);
+
+    idx = *hisidx + viminfo_hisidx[type];
+    if (idx >= hislen)
+	idx -= hislen;
+    else if (idx < 0)
+	idx = hislen - 1;
+    if (viminfo_add_at_front)
+	*hisidx = idx;
+    else
+    {
+	if (*hisidx == -1)
+	    *hisidx = hislen - 1;
+	do
+	{
+	    if (histentry[idx].hisstr != NULL || histentry[idx].viminfo)
+		break;
+	    if (++idx == hislen)
+		idx = 0;
+	} while (idx != *hisidx);
+	if (idx != *hisidx && --idx < 0)
+	    idx = hislen - 1;
+    }
+    for (i = 0; i < viminfo_hisidx[type]; i++)
+    {
+	vim_free(histentry[idx].hisstr);
+	histentry[idx].hisstr = viminfo_history[type][i].hisstr;
+	histentry[idx].viminfo = TRUE;
+	histentry[idx].time_set = viminfo_history[type][i].time_set;
+	if (--idx < 0)
+	    idx = hislen - 1;
+    }
+    idx += 1;
+    idx %= hislen;
+    for (i = 0; i < viminfo_hisidx[type]; i++)
+    {
+	histentry[idx++].hisnum = ++*hisnum;
+	idx %= hislen;
+    }
+}
+
+    static int
+sort_hist(const void *s1, const void *s2)
+{
+    histentry_T *p1 = *(histentry_T **)s1;
+    histentry_T *p2 = *(histentry_T **)s2;
+
+    if (p1->time_set < p2->time_set) return -1;
+    if (p1->time_set > p2->time_set) return 1;
+    return 0;
+}
+
+/*
+ * Merge history lines from viminfo and lines typed in this Vim based on the
+ * timestamp;
+ */
+    static void
+merge_history(int type)
+{
+    int		max_len;
+    histentry_T **tot_hist;
+    histentry_T *new_hist;
+    int		i;
+    int		len;
+    int		hislen = get_hislen();
+    histentry_T *histentry = get_histentry(type);
+    int		*hisidx = get_hisidx(type);
+    int		*hisnum = get_hisnum(type);
+
+    // Make one long list with all entries.
+    max_len = hislen + viminfo_hisidx[type];
+    tot_hist = ALLOC_MULT(histentry_T *, max_len);
+    new_hist = ALLOC_MULT(histentry_T, hislen );
+    if (tot_hist == NULL || new_hist == NULL)
+    {
+	vim_free(tot_hist);
+	vim_free(new_hist);
+	return;
+    }
+    for (i = 0; i < viminfo_hisidx[type]; i++)
+	tot_hist[i] = &viminfo_history[type][i];
+    len = i;
+    for (i = 0; i < hislen; i++)
+	if (histentry[i].hisstr != NULL)
+	    tot_hist[len++] = &histentry[i];
+
+    // Sort the list on timestamp.
+    qsort((void *)tot_hist, (size_t)len, sizeof(histentry_T *), sort_hist);
+
+    // Keep the newest ones.
+    for (i = 0; i < hislen; i++)
+    {
+	if (i < len)
+	{
+	    new_hist[i] = *tot_hist[i];
+	    tot_hist[i]->hisstr = NULL;
+	    if (new_hist[i].hisnum == 0)
+		new_hist[i].hisnum = ++*hisnum;
+	}
+	else
+	    clear_hist_entry(&new_hist[i]);
+    }
+    *hisidx = (i < len ? i : len) - 1;
+
+    // Free what is not kept.
+    for (i = 0; i < viminfo_hisidx[type]; i++)
+	vim_free(viminfo_history[type][i].hisstr);
+    for (i = 0; i < hislen; i++)
+	vim_free(histentry[i].hisstr);
+    vim_free(histentry);
+    set_histentry(type, new_hist);
+    vim_free(tot_hist);
+}
+
+/*
+ * Finish reading history lines from viminfo.  Not used when writing viminfo.
+ */
+    static void
+finish_viminfo_history(vir_T *virp)
+{
+    int	type;
+    int merge = virp->vir_version >= VIMINFO_VERSION_WITH_HISTORY;
+
+    for (type = 0; type < HIST_COUNT; ++type)
+    {
+	if (get_histentry(type) == NULL)
+	    continue;
+
+	if (merge)
+	    merge_history(type);
+	else
+	    concat_history(type);
+
+	VIM_CLEAR(viminfo_history[type]);
+	viminfo_hisidx[type] = 0;
+    }
+}
+
+/*
+ * Write history to viminfo file in "fp".
+ * When "merge" is TRUE merge history lines with a previously read viminfo
+ * file, data is in viminfo_history[].
+ * When "merge" is FALSE just write all history lines.  Used for ":wviminfo!".
+ */
+    static void
+write_viminfo_history(FILE *fp, int merge)
+{
+    int	    i;
+    int	    type;
+    int	    num_saved;
+    int     round;
+    int	    hislen;
+
+    init_history();
+    hislen = get_hislen();
+    if (hislen == 0)
+	return;
+    for (type = 0; type < HIST_COUNT; ++type)
+    {
+	histentry_T *histentry = get_histentry(type);
+	int	    *hisidx = get_hisidx(type);
+
+	num_saved = get_viminfo_parameter(hist_type2char(type, FALSE));
+	if (num_saved == 0)
+	    continue;
+	if (num_saved < 0)  // Use default
+	    num_saved = hislen;
+	fprintf(fp, _("\n# %s History (newest to oldest):\n"),
+			    type == HIST_CMD ? _("Command Line") :
+			    type == HIST_SEARCH ? _("Search String") :
+			    type == HIST_EXPR ? _("Expression") :
+			    type == HIST_INPUT ? _("Input Line") :
+					_("Debug Line"));
+	if (num_saved > hislen)
+	    num_saved = hislen;
+
+	/*
+	 * Merge typed and viminfo history:
+	 * round 1: history of typed commands.
+	 * round 2: history from recently read viminfo.
+	 */
+	for (round = 1; round <= 2; ++round)
+	{
+	    if (round == 1)
+		// start at newest entry, somewhere in the list
+		i = *hisidx;
+	    else if (viminfo_hisidx[type] > 0)
+		// start at newest entry, first in the list
+		i = 0;
+	    else
+		// empty list
+		i = -1;
+	    if (i >= 0)
+		while (num_saved > 0
+			&& !(round == 2 && i >= viminfo_hisidx[type]))
+		{
+		    char_u  *p;
+		    time_t  timestamp;
+		    int	    c = NUL;
+
+		    if (round == 1)
+		    {
+			p = histentry[i].hisstr;
+			timestamp = histentry[i].time_set;
+		    }
+		    else
+		    {
+			p = viminfo_history[type] == NULL ? NULL
+					    : viminfo_history[type][i].hisstr;
+			timestamp = viminfo_history[type] == NULL ? 0
+					  : viminfo_history[type][i].time_set;
+		    }
+
+		    if (p != NULL && (round == 2
+				       || !merge
+				       || !histentry[i].viminfo))
+		    {
+			--num_saved;
+			fputc(hist_type2char(type, TRUE), fp);
+			// For the search history: put the separator in the
+			// second column; use a space if there isn't one.
+			if (type == HIST_SEARCH)
+			{
+			    c = p[STRLEN(p) + 1];
+			    putc(c == NUL ? ' ' : c, fp);
+			}
+			viminfo_writestring(fp, p);
+
+			{
+			    char    cbuf[NUMBUFLEN];
+
+			    // New style history with a bar line. Format:
+			    // |{bartype},{histtype},{timestamp},{separator},"text"
+			    if (c == NUL)
+				cbuf[0] = NUL;
+			    else
+				sprintf(cbuf, "%d", c);
+			    fprintf(fp, "|%d,%d,%ld,%s,", BARTYPE_HISTORY,
+						 type, (long)timestamp, cbuf);
+			    barline_writestring(fp, p, LSIZE - 20);
+			    putc('\n', fp);
+			}
+		    }
+		    if (round == 1)
+		    {
+			// Decrement index, loop around and stop when back at
+			// the start.
+			if (--i < 0)
+			    i = hislen - 1;
+			if (i == *hisidx)
+			    break;
+		    }
+		    else
+		    {
+			// Increment index. Stop at the end in the while.
+			++i;
+		    }
+		}
+	}
+	for (i = 0; i < viminfo_hisidx[type]; ++i)
+	    if (viminfo_history[type] != NULL)
+		vim_free(viminfo_history[type][i].hisstr);
+	VIM_CLEAR(viminfo_history[type]);
+	viminfo_hisidx[type] = 0;
+    }
+}
+#endif // FEAT_VIMINFO
+
     static void
 write_viminfo_barlines(vir_T *virp, FILE *fp_out)
 {