Adding upstream version 3:4.8.29.upstream/3%4.8.29upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3651 insertions, 0 deletions

diff --git a/src/diffviewer/ydiff.c b/src/diffviewer/ydiff.c
new file mode 100644
index 0000000..afe1dc1
--- /dev/null
+++ b/src/diffviewer/ydiff.c
@@ -0,0 +1,3651 @@
+/*
+   File difference viewer
+
+   Copyright (C) 2007-2022
+   Free Software Foundation, Inc.
+
+   Written by:
+   Daniel Borca <dborca@yahoo.com>, 2007
+   Slava Zanko <slavazanko@gmail.com>, 2010, 2013
+   Andrew Borodin <aborodin@vmail.ru>, 2010-2022
+   Ilia Maslakov <il.smind@gmail.com>, 2010
+
+   This file is part of the Midnight Commander.
+
+   The Midnight Commander is free software: you can redistribute it
+   and/or modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation, either version 3 of the License,
+   or (at your option) any later version.
+
+   The Midnight Commander 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <config.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <stddef.h>             /* ptrdiff_t */
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include "lib/global.h"
+#include "lib/tty/tty.h"
+#include "lib/tty/color.h"
+#include "lib/tty/key.h"
+#include "lib/skin.h"           /* EDITOR_NORMAL_COLOR */
+#include "lib/vfs/vfs.h"        /* mc_opendir, mc_readdir, mc_closedir, */
+#include "lib/util.h"
+#include "lib/widget.h"
+#include "lib/strutil.h"
+#include "lib/strescape.h"      /* strutils_glob_escape() */
+#ifdef HAVE_CHARSET
+#include "lib/charsets.h"
+#endif
+#include "lib/event.h"          /* mc_event_raise() */
+
+#include "src/filemanager/cmd.h"        /* edit_file_at_line() */
+#include "src/filemanager/panel.h"
+#include "src/filemanager/layout.h"     /* Needed for get_current_index and get_other_panel */
+
+#include "src/execute.h"        /* toggle_subshell() */
+#include "src/keymap.h"
+#include "src/setup.h"
+#include "src/history.h"
+#ifdef HAVE_CHARSET
+#include "src/selcodepage.h"
+#endif
+
+#include "ydiff.h"
+#include "internal.h"
+
+/*** global variables ****************************************************************************/
+
+/*** file scope macro definitions ****************************************************************/
+
+#define g_array_foreach(a, TP, cbf) \
+do { \
+    size_t g_array_foreach_i;\
+    \
+    for (g_array_foreach_i = 0; g_array_foreach_i < a->len; g_array_foreach_i++) \
+    { \
+        TP *g_array_foreach_var; \
+        \
+        g_array_foreach_var = &g_array_index (a, TP, g_array_foreach_i); \
+        (*cbf) (g_array_foreach_var); \
+    } \
+} while (0)
+
+#define FILE_READ_BUF 4096
+#define FILE_FLAG_TEMP (1 << 0)
+
+#define ADD_CH '+'
+#define DEL_CH '-'
+#define CHG_CH '*'
+#define EQU_CH ' '
+
+#define HDIFF_ENABLE 1
+#define HDIFF_MINCTX 5
+#define HDIFF_DEPTH 10
+
+#define FILE_DIRTY(fs) \
+do \
+{ \
+    (fs)->pos = 0; \
+    (fs)->len = 0;  \
+} \
+while (0)
+
+/*** file scope type declarations ****************************************************************/
+
+typedef enum
+{
+    FROM_LEFT_TO_RIGHT,
+    FROM_RIGHT_TO_LEFT
+} action_direction_t;
+
+/*** file scope variables ************************************************************************/
+
+/*** file scope functions ************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+
+static inline int
+TAB_SKIP (int ts, int pos)
+{
+    if (ts > 0 && ts < 9)
+        return ts - pos % ts;
+    else
+        return 8 - pos % 8;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static gboolean
+rewrite_backup_content (const vfs_path_t * from_file_name_vpath, const char *to_file_name)
+{
+    FILE *backup_fd;
+    char *contents;
+    gsize length;
+    const char *from_file_name;
+
+    from_file_name = vfs_path_get_by_index (from_file_name_vpath, -1)->path;
+    if (!g_file_get_contents (from_file_name, &contents, &length, NULL))
+        return FALSE;
+
+    backup_fd = fopen (to_file_name, "w");
+    if (backup_fd == NULL)
+    {
+        g_free (contents);
+        return FALSE;
+    }
+
+    length = fwrite ((const void *) contents, length, 1, backup_fd);
+
+    fflush (backup_fd);
+    fclose (backup_fd);
+    g_free (contents);
+    return TRUE;
+}
+
+/* buffered I/O ************************************************************* */
+
+/**
+ * Try to open a temporary file.
+ * @note the name is not altered if this function fails
+ *
+ * @param[out] name address of a pointer to store the temporary name
+ * @return file descriptor on success, negative on error
+ */
+
+static int
+open_temp (void **name)
+{
+    int fd;
+    vfs_path_t *diff_file_name = NULL;
+
+    fd = mc_mkstemps (&diff_file_name, "mcdiff", NULL);
+    if (fd == -1)
+    {
+        message (D_ERROR, MSG_ERROR,
+                 _("Cannot create temporary diff file\n%s"), unix_error_string (errno));
+        return -1;
+    }
+
+    *name = vfs_path_free (diff_file_name, FALSE);
+    return fd;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Alocate file structure and associate file descriptor to it.
+ *
+ * @param fd file descriptor
+ * @return file structure
+ */
+
+static FBUF *
+f_dopen (int fd)
+{
+    FBUF *fs;
+
+    if (fd < 0)
+        return NULL;
+
+    fs = g_try_malloc (sizeof (FBUF));
+    if (fs == NULL)
+        return NULL;
+
+    fs->buf = g_try_malloc (FILE_READ_BUF);
+    if (fs->buf == NULL)
+    {
+        g_free (fs);
+        return NULL;
+    }
+
+    fs->fd = fd;
+    FILE_DIRTY (fs);
+    fs->flags = 0;
+    fs->data = NULL;
+
+    return fs;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Free file structure without closing the file.
+ *
+ * @param fs file structure
+ * @return 0 on success, non-zero on error
+ */
+
+static int
+f_free (FBUF * fs)
+{
+    int rv = 0;
+
+    if (fs->flags & FILE_FLAG_TEMP)
+    {
+        rv = unlink (fs->data);
+        g_free (fs->data);
+    }
+    g_free (fs->buf);
+    g_free (fs);
+    return rv;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Open a binary temporary file in R/W mode.
+ * @note the file will be deleted when closed
+ *
+ * @return file structure
+ */
+static FBUF *
+f_temp (void)
+{
+    int fd;
+    FBUF *fs;
+
+    fs = f_dopen (0);
+    if (fs == NULL)
+        return NULL;
+
+    fd = open_temp (&fs->data);
+    if (fd < 0)
+    {
+        f_free (fs);
+        return NULL;
+    }
+
+    fs->fd = fd;
+    fs->flags = FILE_FLAG_TEMP;
+    return fs;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Open a binary file in specified mode.
+ *
+ * @param filename file name
+ * @param flags open mode, a combination of O_RDONLY, O_WRONLY, O_RDWR
+ *
+ * @return file structure
+ */
+
+static FBUF *
+f_open (const char *filename, int flags)
+{
+    int fd;
+    FBUF *fs;
+
+    fs = f_dopen (0);
+    if (fs == NULL)
+        return NULL;
+
+    fd = open (filename, flags);
+    if (fd < 0)
+    {
+        f_free (fs);
+        return NULL;
+    }
+
+    fs->fd = fd;
+    return fs;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Read a line of bytes from file until newline or EOF.
+ * @note does not stop on null-byte
+ * @note buf will not be null-terminated
+ *
+ * @param buf destination buffer
+ * @param size size of buffer
+ * @param fs file structure
+ *
+ * @return number of bytes read
+ */
+
+static size_t
+f_gets (char *buf, size_t size, FBUF * fs)
+{
+    size_t j = 0;
+
+    do
+    {
+        int i;
+        int stop = 0;
+
+        for (i = fs->pos; j < size && i < fs->len && !stop; i++, j++)
+        {
+            buf[j] = fs->buf[i];
+            if (buf[j] == '\n')
+                stop = 1;
+        }
+        fs->pos = i;
+
+        if (j == size || stop)
+            break;
+
+        fs->pos = 0;
+        fs->len = read (fs->fd, fs->buf, FILE_READ_BUF);
+    }
+    while (fs->len > 0);
+
+    return j;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Seek into file.
+ * @note avoids thrashing read cache when possible
+ *
+ * @param fs file structure
+ * @param off offset
+ * @param whence seek directive: SEEK_SET, SEEK_CUR or SEEK_END
+ *
+ * @return position in file, starting from begginning
+ */
+
+static off_t
+f_seek (FBUF * fs, off_t off, int whence)
+{
+    off_t rv;
+
+    if (fs->len && whence != SEEK_END)
+    {
+        rv = lseek (fs->fd, 0, SEEK_CUR);
+        if (rv != -1)
+        {
+            if (whence == SEEK_CUR)
+            {
+                whence = SEEK_SET;
+                off += rv - fs->len + fs->pos;
+            }
+            if (off - rv >= -fs->len && off - rv <= 0)
+            {
+                fs->pos = fs->len + off - rv;
+                return off;
+            }
+        }
+    }
+
+    rv = lseek (fs->fd, off, whence);
+    if (rv != -1)
+        FILE_DIRTY (fs);
+    return rv;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Seek to the beginning of file, thrashing read cache.
+ *
+ * @param fs file structure
+ *
+ * @return 0 if success, non-zero on error
+ */
+
+static off_t
+f_reset (FBUF * fs)
+{
+    off_t rv;
+
+    rv = lseek (fs->fd, 0, SEEK_SET);
+    if (rv != -1)
+        FILE_DIRTY (fs);
+    return rv;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Write bytes to file.
+ * @note thrashes read cache
+ *
+ * @param fs file structure
+ * @param buf source buffer
+ * @param size size of buffer
+ *
+ * @return number of written bytes, -1 on error
+ */
+
+static ssize_t
+f_write (FBUF * fs, const char *buf, size_t size)
+{
+    ssize_t rv;
+
+    rv = write (fs->fd, buf, size);
+    if (rv >= 0)
+        FILE_DIRTY (fs);
+    return rv;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Truncate file to the current position.
+ * @note thrashes read cache
+ *
+ * @param fs file structure
+ *
+ * @return current file size on success, negative on error
+ */
+
+static off_t
+f_trunc (FBUF * fs)
+{
+    off_t off;
+
+    off = lseek (fs->fd, 0, SEEK_CUR);
+    if (off != -1)
+    {
+        int rv;
+
+        rv = ftruncate (fs->fd, off);
+        if (rv != 0)
+            off = -1;
+        else
+            FILE_DIRTY (fs);
+    }
+    return off;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Close file.
+ * @note if this is temporary file, it is deleted
+ *
+ * @param fs file structure
+ * @return 0 on success, non-zero on error
+ */
+
+static int
+f_close (FBUF * fs)
+{
+    int rv = -1;
+
+    if (fs != NULL)
+    {
+        rv = close (fs->fd);
+        f_free (fs);
+    }
+
+    return rv;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Create pipe stream to process.
+ *
+ * @param cmd shell command line
+ * @param flags open mode, either O_RDONLY or O_WRONLY
+ *
+ * @return file structure
+ */
+
+static FBUF *
+p_open (const char *cmd, int flags)
+{
+    FILE *f;
+    FBUF *fs;
+    const char *type = NULL;
+
+    if (flags == O_RDONLY)
+        type = "r";
+    else if (flags == O_WRONLY)
+        type = "w";
+
+    if (type == NULL)
+        return NULL;
+
+    fs = f_dopen (0);
+    if (fs == NULL)
+        return NULL;
+
+    f = popen (cmd, type);
+    if (f == NULL)
+    {
+        f_free (fs);
+        return NULL;
+    }
+
+    fs->fd = fileno (f);
+    fs->data = f;
+    return fs;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Close pipe stream.
+ *
+ * @param fs structure
+ * @return 0 on success, non-zero on error
+ */
+
+static int
+p_close (FBUF * fs)
+{
+    int rv = -1;
+
+    if (fs != NULL)
+    {
+        rv = pclose (fs->data);
+        f_free (fs);
+    }
+
+    return rv;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Get one char (byte) from string
+ *
+ * @param str ...
+ * @param ch ...
+ * @return TRUE on success, FALSE otherwise
+ */
+
+static gboolean
+dview_get_byte (const char *str, int *ch)
+{
+    if (str == NULL)
+        return FALSE;
+
+    *ch = (unsigned char) (*str);
+    return TRUE;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+#ifdef HAVE_CHARSET
+/**
+ * Get utf multibyte char from string
+ *
+ * @param str ...
+ * @param ch ...
+ * @param ch_length ...
+ * @return TRUE on success, FALSE otherwise
+ */
+
+static gboolean
+dview_get_utf (const char *str, int *ch, int *ch_length)
+{
+    if (str == NULL)
+        return FALSE;
+
+    *ch = g_utf8_get_char_validated (str, -1);
+
+    if (*ch < 0)
+    {
+        *ch = (unsigned char) (*str);
+        *ch_length = 1;
+    }
+    else
+    {
+        char *next_ch;
+
+        /* Calculate UTF-8 char length */
+        next_ch = g_utf8_next_char (str);
+        *ch_length = next_ch - str;
+    }
+
+    return TRUE;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+dview_str_utf8_offset_to_pos (const char *text, size_t length)
+{
+    ptrdiff_t result;
+
+    if (text == NULL || text[0] == '\0')
+        return length;
+
+    if (g_utf8_validate (text, -1, NULL))
+        result = g_utf8_offset_to_pointer (text, length) - text;
+    else
+    {
+        gunichar uni;
+        char *tmpbuf, *buffer;
+
+        buffer = tmpbuf = g_strdup (text);
+        while (tmpbuf[0] != '\0')
+        {
+            uni = g_utf8_get_char_validated (tmpbuf, -1);
+            if ((uni != (gunichar) (-1)) && (uni != (gunichar) (-2)))
+                tmpbuf = g_utf8_next_char (tmpbuf);
+            else
+            {
+                tmpbuf[0] = '.';
+                tmpbuf++;
+            }
+        }
+        result = g_utf8_offset_to_pointer (tmpbuf, length) - tmpbuf;
+        g_free (buffer);
+    }
+    return MAX (length, (size_t) result);
+}
+#endif /*HAVE_CHARSET */
+
+/* --------------------------------------------------------------------------------------------- */
+
+/* diff parse *************************************************************** */
+
+/**
+ * Read decimal number from string.
+ *
+ * @param[in,out] str string to parse
+ * @param[out] n extracted number
+ * @return 0 if success, otherwise non-zero
+ */
+
+static int
+scan_deci (const char **str, int *n)
+{
+    const char *p = *str;
+    char *q;
+
+    errno = 0;
+    *n = strtol (p, &q, 10);
+    if (errno != 0 || p == q)
+        return -1;
+    *str = q;
+    return 0;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Parse line for diff statement.
+ *
+ * @param p string to parse
+ * @param ops list of diff statements
+ * @return 0 if success, otherwise non-zero
+ */
+
+static int
+scan_line (const char *p, GArray * ops)
+{
+    DIFFCMD op;
+
+    int f1, f2;
+    int t1, t2;
+    int cmd;
+    int range;
+
+    /* handle the following cases:
+     *  NUMaNUM[,NUM]
+     *  NUM[,NUM]cNUM[,NUM]
+     *  NUM[,NUM]dNUM
+     * where NUM is a positive integer
+     */
+
+    if (scan_deci (&p, &f1) != 0 || f1 < 0)
+        return -1;
+
+    f2 = f1;
+    range = 0;
+    if (*p == ',')
+    {
+        p++;
+        if (scan_deci (&p, &f2) != 0 || f2 < f1)
+            return -1;
+
+        range = 1;
+    }
+
+    cmd = *p++;
+    if (cmd == 'a')
+    {
+        if (range != 0)
+            return -1;
+    }
+    else if (cmd != 'c' && cmd != 'd')
+        return -1;
+
+    if (scan_deci (&p, &t1) != 0 || t1 < 0)
+        return -1;
+
+    t2 = t1;
+    range = 0;
+    if (*p == ',')
+    {
+        p++;
+        if (scan_deci (&p, &t2) != 0 || t2 < t1)
+            return -1;
+
+        range = 1;
+    }
+
+    if (cmd == 'd' && range != 0)
+        return -1;
+
+    op.a[0][0] = f1;
+    op.a[0][1] = f2;
+    op.cmd = cmd;
+    op.a[1][0] = t1;
+    op.a[1][1] = t2;
+    g_array_append_val (ops, op);
+    return 0;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Parse diff output and extract diff statements.
+ *
+ * @param f stream to read from
+ * @param ops list of diff statements to fill
+ * @return positive number indicating number of hunks, otherwise negative
+ */
+
+static int
+scan_diff (FBUF * f, GArray * ops)
+{
+    int sz;
+    char buf[BUFSIZ];
+
+    while ((sz = f_gets (buf, sizeof (buf) - 1, f)) != 0)
+    {
+        if (isdigit (buf[0]))
+        {
+            if (buf[sz - 1] != '\n')
+                return -1;
+
+            buf[sz] = '\0';
+            if (scan_line (buf, ops) != 0)
+                return -1;
+
+            continue;
+        }
+
+        while (buf[sz - 1] != '\n' && (sz = f_gets (buf, sizeof (buf), f)) != 0)
+            ;
+    }
+
+    return ops->len;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Invoke diff and extract diff statements.
+ *
+ * @param args extra arguments to be passed to diff
+ * @param extra more arguments to be passed to diff
+ * @param file1 first file to compare
+ * @param file2 second file to compare
+ * @param ops list of diff statements to fill
+ *
+ * @return positive number indicating number of hunks, otherwise negative
+ */
+
+static int
+dff_execute (const char *args, const char *extra, const char *file1, const char *file2,
+             GArray * ops)
+{
+    static const char *opt =
+        " --old-group-format='%df%(f=l?:,%dl)d%dE\n'"
+        " --new-group-format='%dea%dF%(F=L?:,%dL)\n'"
+        " --changed-group-format='%df%(f=l?:,%dl)c%dF%(F=L?:,%dL)\n'"
+        " --unchanged-group-format=''";
+
+    int rv;
+    FBUF *f;
+    char *cmd;
+    int code;
+    char *file1_esc, *file2_esc;
+
+    /* escape potential $ to avoid shell variable substitutions in popen() */
+    file1_esc = strutils_shell_escape (file1);
+    file2_esc = strutils_shell_escape (file2);
+    cmd = g_strdup_printf ("diff %s %s %s %s %s", args, extra, opt, file1_esc, file2_esc);
+    g_free (file1_esc);
+    g_free (file2_esc);
+
+    if (cmd == NULL)
+        return -1;
+
+    f = p_open (cmd, O_RDONLY);
+    g_free (cmd);
+
+    if (f == NULL)
+        return -1;
+
+    rv = scan_diff (f, ops);
+    code = p_close (f);
+
+    if (rv < 0 || code == -1 || !WIFEXITED (code) || WEXITSTATUS (code) == 2)
+        rv = -1;
+
+    return rv;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Reparse and display file according to diff statements.
+ *
+ * @param ord DIFF_LEFT if 1nd file is displayed , DIFF_RIGHT if 2nd file is displayed.
+ * @param filename file name to display
+ * @param ops list of diff statements
+ * @param printer printf-like function to be used for displaying
+ * @param ctx printer context
+ *
+ * @return 0 if success, otherwise non-zero
+ */
+
+static int
+dff_reparse (diff_place_t ord, const char *filename, const GArray * ops, DFUNC printer, void *ctx)
+{
+    size_t i;
+    FBUF *f;
+    size_t sz;
+    char buf[BUFSIZ];
+    int line = 0;
+    off_t off = 0;
+    const DIFFCMD *op;
+    diff_place_t eff;
+    int add_cmd;
+    int del_cmd;
+
+    f = f_open (filename, O_RDONLY);
+    if (f == NULL)
+        return -1;
+
+    ord &= 1;
+    eff = ord;
+
+    add_cmd = 'a';
+    del_cmd = 'd';
+    if (ord != 0)
+    {
+        add_cmd = 'd';
+        del_cmd = 'a';
+    }
+#define F1 a[eff][0]
+#define F2 a[eff][1]
+#define T1 a[ ord^1 ][0]
+#define T2 a[ ord^1 ][1]
+    for (i = 0; i < ops->len; i++)
+    {
+        int n;
+
+        op = &g_array_index (ops, DIFFCMD, i);
+        n = op->F1 - (op->cmd != add_cmd);
+
+        while (line < n && (sz = f_gets (buf, sizeof (buf), f)) != 0)
+        {
+            line++;
+            printer (ctx, EQU_CH, line, off, sz, buf);
+            off += sz;
+            while (buf[sz - 1] != '\n')
+            {
+                sz = f_gets (buf, sizeof (buf), f);
+                if (sz == 0)
+                {
+                    printer (ctx, 0, 0, 0, 1, "\n");
+                    break;
+                }
+                printer (ctx, 0, 0, 0, sz, buf);
+                off += sz;
+            }
+        }
+
+        if (line != n)
+            goto err;
+
+        if (op->cmd == add_cmd)
+        {
+            n = op->T2 - op->T1 + 1;
+            while (n != 0)
+            {
+                printer (ctx, DEL_CH, 0, 0, 1, "\n");
+                n--;
+            }
+        }
+
+        if (op->cmd == del_cmd)
+        {
+            n = op->F2 - op->F1 + 1;
+            while (n != 0 && (sz = f_gets (buf, sizeof (buf), f)) != 0)
+            {
+                line++;
+                printer (ctx, ADD_CH, line, off, sz, buf);
+                off += sz;
+                while (buf[sz - 1] != '\n')
+                {
+                    sz = f_gets (buf, sizeof (buf), f);
+                    if (sz == 0)
+                    {
+                        printer (ctx, 0, 0, 0, 1, "\n");
+                        break;
+                    }
+                    printer (ctx, 0, 0, 0, sz, buf);
+                    off += sz;
+                }
+                n--;
+            }
+
+            if (n != 0)
+                goto err;
+        }
+
+        if (op->cmd == 'c')
+        {
+            n = op->F2 - op->F1 + 1;
+            while (n != 0 && (sz = f_gets (buf, sizeof (buf), f)) != 0)
+            {
+                line++;
+                printer (ctx, CHG_CH, line, off, sz, buf);
+                off += sz;
+                while (buf[sz - 1] != '\n')
+                {
+                    sz = f_gets (buf, sizeof (buf), f);
+                    if (sz == 0)
+                    {
+                        printer (ctx, 0, 0, 0, 1, "\n");
+                        break;
+                    }
+                    printer (ctx, 0, 0, 0, sz, buf);
+                    off += sz;
+                }
+                n--;
+            }
+
+            if (n != 0)
+                goto err;
+
+            n = op->T2 - op->T1 - (op->F2 - op->F1);
+            while (n > 0)
+            {
+                printer (ctx, CHG_CH, 0, 0, 1, "\n");
+                n--;
+            }
+        }
+    }
+#undef T2
+#undef T1
+#undef F2
+#undef F1
+
+    while ((sz = f_gets (buf, sizeof (buf), f)) != 0)
+    {
+        line++;
+        printer (ctx, EQU_CH, line, off, sz, buf);
+        off += sz;
+        while (buf[sz - 1] != '\n')
+        {
+            sz = f_gets (buf, sizeof (buf), f);
+            if (sz == 0)
+            {
+                printer (ctx, 0, 0, 0, 1, "\n");
+                break;
+            }
+            printer (ctx, 0, 0, 0, sz, buf);
+            off += sz;
+        }
+    }
+
+    f_close (f);
+    return 0;
+
+  err:
+    f_close (f);
+    return -1;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/* horizontal diff ********************************************************** */
+
+/**
+ * Longest common substring.
+ *
+ * @param s first string
+ * @param m length of first string
+ * @param t second string
+ * @param n length of second string
+ * @param ret list of offsets for longest common substrings inside each string
+ * @param min minimum length of common substrings
+ *
+ * @return 0 if success, nonzero otherwise
+ */
+
+static int
+lcsubstr (const char *s, int m, const char *t, int n, GArray * ret, int min)
+{
+    int i, j;
+    int *Lprev, *Lcurr;
+    int z = 0;
+
+    if (m < min || n < min)
+    {
+        /* XXX early culling */
+        return 0;
+    }
+
+    Lprev = g_try_new0 (int, n + 1);
+    if (Lprev == NULL)
+        return -1;
+
+    Lcurr = g_try_new0 (int, n + 1);
+    if (Lcurr == NULL)
+    {
+        g_free (Lprev);
+        return -1;
+    }
+
+    for (i = 0; i < m; i++)
+    {
+        int *L;
+
+        L = Lprev;
+        Lprev = Lcurr;
+        Lcurr = L;
+#ifdef USE_MEMSET_IN_LCS
+        memset (Lcurr, 0, (n + 1) * sizeof (*Lcurr));
+#endif
+        for (j = 0; j < n; j++)
+        {
+#ifndef USE_MEMSET_IN_LCS
+            Lcurr[j + 1] = 0;
+#endif
+            if (s[i] == t[j])
+            {
+                int v;
+
+                v = Lprev[j] + 1;
+                Lcurr[j + 1] = v;
+                if (z < v)
+                {
+                    z = v;
+                    g_array_set_size (ret, 0);
+                }
+                if (z == v && z >= min)
+                {
+                    int off0, off1;
+                    size_t k;
+
+                    off0 = i - z + 1;
+                    off1 = j - z + 1;
+
+                    for (k = 0; k < ret->len; k++)
+                    {
+                        PAIR *p = (PAIR *) g_array_index (ret, PAIR, k);
+                        if ((*p)[0] == off0 || (*p)[1] >= off1)
+                            break;
+                    }
+                    if (k == ret->len)
+                    {
+                        PAIR p2;
+
+                        p2[0] = off0;
+                        p2[1] = off1;
+                        g_array_append_val (ret, p2);
+                    }
+                }
+            }
+        }
+    }
+
+    g_free (Lcurr);
+    g_free (Lprev);
+    return z;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Scan recursively for common substrings and build ranges.
+ *
+ * @param s first string
+ * @param t second string
+ * @param bracket current limits for both of the strings
+ * @param min minimum length of common substrings
+ * @param hdiff list of horizontal diff ranges to fill
+ * @param depth recursion depth
+ *
+ * @return 0 if success, nonzero otherwise
+ */
+
+static gboolean
+hdiff_multi (const char *s, const char *t, const BRACKET bracket, int min, GArray * hdiff,
+             unsigned int depth)
+{
+    BRACKET p;
+
+    if (depth-- != 0)
+    {
+        GArray *ret;
+        BRACKET b;
+        int len;
+
+        ret = g_array_new (FALSE, TRUE, sizeof (PAIR));
+        if (ret == NULL)
+            return FALSE;
+
+        len = lcsubstr (s + bracket[DIFF_LEFT].off, bracket[DIFF_LEFT].len,
+                        t + bracket[DIFF_RIGHT].off, bracket[DIFF_RIGHT].len, ret, min);
+        if (ret->len != 0)
+        {
+            size_t k = 0;
+            const PAIR *data = (const PAIR *) &g_array_index (ret, PAIR, 0);
+            const PAIR *data2;
+
+            b[DIFF_LEFT].off = bracket[DIFF_LEFT].off;
+            b[DIFF_LEFT].len = (*data)[0];
+            b[DIFF_RIGHT].off = bracket[DIFF_RIGHT].off;
+            b[DIFF_RIGHT].len = (*data)[1];
+            if (!hdiff_multi (s, t, b, min, hdiff, depth))
+                return FALSE;
+
+            for (k = 0; k < ret->len - 1; k++)
+            {
+                data = (const PAIR *) &g_array_index (ret, PAIR, k);
+                data2 = (const PAIR *) &g_array_index (ret, PAIR, k + 1);
+                b[DIFF_LEFT].off = bracket[DIFF_LEFT].off + (*data)[0] + len;
+                b[DIFF_LEFT].len = (*data2)[0] - (*data)[0] - len;
+                b[DIFF_RIGHT].off = bracket[DIFF_RIGHT].off + (*data)[1] + len;
+                b[DIFF_RIGHT].len = (*data2)[1] - (*data)[1] - len;
+                if (!hdiff_multi (s, t, b, min, hdiff, depth))
+                    return FALSE;
+            }
+            data = (const PAIR *) &g_array_index (ret, PAIR, k);
+            b[DIFF_LEFT].off = bracket[DIFF_LEFT].off + (*data)[0] + len;
+            b[DIFF_LEFT].len = bracket[DIFF_LEFT].len - (*data)[0] - len;
+            b[DIFF_RIGHT].off = bracket[DIFF_RIGHT].off + (*data)[1] + len;
+            b[DIFF_RIGHT].len = bracket[DIFF_RIGHT].len - (*data)[1] - len;
+            if (!hdiff_multi (s, t, b, min, hdiff, depth))
+                return FALSE;
+
+            g_array_free (ret, TRUE);
+            return TRUE;
+        }
+    }
+
+    p[DIFF_LEFT].off = bracket[DIFF_LEFT].off;
+    p[DIFF_LEFT].len = bracket[DIFF_LEFT].len;
+    p[DIFF_RIGHT].off = bracket[DIFF_RIGHT].off;
+    p[DIFF_RIGHT].len = bracket[DIFF_RIGHT].len;
+    g_array_append_val (hdiff, p);
+
+    return TRUE;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Build list of horizontal diff ranges.
+ *
+ * @param s first string
+ * @param m length of first string
+ * @param t second string
+ * @param n length of second string
+ * @param min minimum length of common substrings
+ * @param hdiff list of horizontal diff ranges to fill
+ * @param depth recursion depth
+ *
+ * @return 0 if success, nonzero otherwise
+ */
+
+static gboolean
+hdiff_scan (const char *s, int m, const char *t, int n, int min, GArray * hdiff, unsigned int depth)
+{
+    int i;
+    BRACKET b;
+
+    /* dumbscan (single horizontal diff) -- does not compress whitespace */
+    for (i = 0; i < m && i < n && s[i] == t[i]; i++)
+        ;
+    for (; m > i && n > i && s[m - 1] == t[n - 1]; m--, n--)
+        ;
+
+    b[DIFF_LEFT].off = i;
+    b[DIFF_LEFT].len = m - i;
+    b[DIFF_RIGHT].off = i;
+    b[DIFF_RIGHT].len = n - i;
+
+    /* smartscan (multiple horizontal diff) */
+    return hdiff_multi (s, t, b, min, hdiff, depth);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/* read line **************************************************************** */
+
+/**
+ * Check if character is inside horizontal diff limits.
+ *
+ * @param k rank of character inside line
+ * @param hdiff horizontal diff structure
+ * @param ord DIFF_LEFT if reading from first file, DIFF_RIGHT if reading from 2nd file
+ *
+ * @return TRUE if inside hdiff limits, FALSE otherwise
+ */
+
+static gboolean
+is_inside (int k, GArray * hdiff, diff_place_t ord)
+{
+    size_t i;
+    BRACKET *b;
+
+    for (i = 0; i < hdiff->len; i++)
+    {
+        int start, end;
+
+        b = &g_array_index (hdiff, BRACKET, i);
+        start = (*b)[ord].off;
+        end = start + (*b)[ord].len;
+        if (k >= start && k < end)
+            return TRUE;
+    }
+    return FALSE;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Copy 'src' to 'dst' expanding tabs.
+ * @note The procedure returns when all bytes are consumed from 'src'
+ *
+ * @param dst destination buffer
+ * @param src source buffer
+ * @param srcsize size of src buffer
+ * @param base virtual base of this string, needed to calculate tabs
+ * @param ts tab size
+ *
+ * @return new virtual base
+ */
+
+static int
+cvt_cpy (char *dst, const char *src, size_t srcsize, int base, int ts)
+{
+    int i;
+
+    for (i = 0; srcsize != 0; i++, src++, dst++, srcsize--)
+    {
+        *dst = *src;
+        if (*src == '\t')
+        {
+            int j;
+
+            j = TAB_SKIP (ts, i + base);
+            i += j - 1;
+            while (j-- > 0)
+                *dst++ = ' ';
+            dst--;
+        }
+    }
+    return i + base;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Copy 'src' to 'dst' expanding tabs.
+ *
+ * @param dst destination buffer
+ * @param dstsize size of dst buffer
+ * @param[in,out] _src source buffer
+ * @param srcsize size of src buffer
+ * @param base virtual base of this string, needed to calculate tabs
+ * @param ts tab size
+ *
+ * @return new virtual base
+ *
+ * @note The procedure returns when all bytes are consumed from 'src'
+ *       or 'dstsize' bytes are written to 'dst'
+ * @note Upon return, 'src' points to the first unwritten character in source
+ */
+
+static int
+cvt_ncpy (char *dst, int dstsize, const char **_src, size_t srcsize, int base, int ts)
+{
+    int i;
+    const char *src = *_src;
+
+    for (i = 0; i < dstsize && srcsize != 0; i++, src++, dst++, srcsize--)
+    {
+        *dst = *src;
+        if (*src == '\t')
+        {
+            int j;
+
+            j = TAB_SKIP (ts, i + base);
+            if (j > dstsize - i)
+                j = dstsize - i;
+            i += j - 1;
+            while (j-- > 0)
+                *dst++ = ' ';
+            dst--;
+        }
+    }
+    *_src = src;
+    return i + base;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Read line from memory, converting tabs to spaces and padding with spaces.
+ *
+ * @param src buffer to read from
+ * @param srcsize size of src buffer
+ * @param dst buffer to read to
+ * @param dstsize size of dst buffer, excluding trailing null
+ * @param skip number of characters to skip
+ * @param ts tab size
+ * @param show_cr show trailing carriage return as ^M
+ *
+ * @return negative on error, otherwise number of bytes except padding
+ */
+
+static int
+cvt_mget (const char *src, size_t srcsize, char *dst, int dstsize, int skip, int ts,
+          gboolean show_cr)
+{
+    int sz = 0;
+
+    if (src != NULL)
+    {
+        int i;
+        char *tmp = dst;
+        const int base = 0;
+
+        for (i = 0; dstsize != 0 && srcsize != 0 && *src != '\n'; i++, src++, srcsize--)
+        {
+            if (*src == '\t')
+            {
+                int j;
+
+                j = TAB_SKIP (ts, i + base);
+                i += j - 1;
+                while (j-- > 0)
+                {
+                    if (skip > 0)
+                        skip--;
+                    else if (dstsize != 0)
+                    {
+                        dstsize--;
+                        *dst++ = ' ';
+                    }
+                }
+            }
+            else if (src[0] == '\r' && (srcsize == 1 || src[1] == '\n'))
+            {
+                if (skip == 0 && show_cr)
+                {
+                    if (dstsize > 1)
+                    {
+                        dstsize -= 2;
+                        *dst++ = '^';
+                        *dst++ = 'M';
+                    }
+                    else
+                    {
+                        dstsize--;
+                        *dst++ = '.';
+                    }
+                }
+                break;
+            }
+            else if (skip > 0)
+            {
+#ifdef HAVE_CHARSET
+                int ch = 0;
+                int ch_length = 1;
+
+                (void) dview_get_utf (src, &ch, &ch_length);
+
+                if (ch_length > 1)
+                    skip += ch_length - 1;
+#endif
+
+                skip--;
+            }
+            else
+            {
+                dstsize--;
+                *dst++ = *src;
+            }
+        }
+        sz = dst - tmp;
+    }
+    while (dstsize != 0)
+    {
+        dstsize--;
+        *dst++ = ' ';
+    }
+    *dst = '\0';
+    return sz;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Read line from memory and build attribute array.
+ *
+ * @param src buffer to read from
+ * @param srcsize size of src buffer
+ * @param dst buffer to read to
+ * @param dstsize size of dst buffer, excluding trailing null
+ * @param skip number of characters to skip
+ * @param ts tab size
+ * @param show_cr show trailing carriage return as ^M
+ * @param hdiff horizontal diff structure
+ * @param ord DIFF_LEFT if reading from first file, DIFF_RIGHT if reading from 2nd file
+ * @param att buffer of attributes
+ *
+ * @return negative on error, otherwise number of bytes except padding
+ */
+
+static int
+cvt_mgeta (const char *src, size_t srcsize, char *dst, int dstsize, int skip, int ts,
+           gboolean show_cr, GArray * hdiff, diff_place_t ord, char *att)
+{
+    int sz = 0;
+
+    if (src != NULL)
+    {
+        int i, k;
+        char *tmp = dst;
+        const int base = 0;
+
+        for (i = 0, k = 0; dstsize != 0 && srcsize != 0 && *src != '\n'; i++, k++, src++, srcsize--)
+        {
+            if (*src == '\t')
+            {
+                int j;
+
+                j = TAB_SKIP (ts, i + base);
+                i += j - 1;
+                while (j-- > 0)
+                {
+                    if (skip != 0)
+                        skip--;
+                    else if (dstsize != 0)
+                    {
+                        dstsize--;
+                        *att++ = is_inside (k, hdiff, ord);
+                        *dst++ = ' ';
+                    }
+                }
+            }
+            else if (src[0] == '\r' && (srcsize == 1 || src[1] == '\n'))
+            {
+                if (skip == 0 && show_cr)
+                {
+                    if (dstsize > 1)
+                    {
+                        dstsize -= 2;
+                        *att++ = is_inside (k, hdiff, ord);
+                        *dst++ = '^';
+                        *att++ = is_inside (k, hdiff, ord);
+                        *dst++ = 'M';
+                    }
+                    else
+                    {
+                        dstsize--;
+                        *att++ = is_inside (k, hdiff, ord);
+                        *dst++ = '.';
+                    }
+                }
+                break;
+            }
+            else if (skip != 0)
+            {
+#ifdef HAVE_CHARSET
+                int ch = 0;
+                int ch_length = 1;
+
+                (void) dview_get_utf (src, &ch, &ch_length);
+                if (ch_length > 1)
+                    skip += ch_length - 1;
+#endif
+
+                skip--;
+            }
+            else
+            {
+                dstsize--;
+                *att++ = is_inside (k, hdiff, ord);
+                *dst++ = *src;
+            }
+        }
+        sz = dst - tmp;
+    }
+    while (dstsize != 0)
+    {
+        dstsize--;
+        *att++ = '\0';
+        *dst++ = ' ';
+    }
+    *dst = '\0';
+    return sz;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/**
+ * Read line from file, converting tabs to spaces and padding with spaces.
+ *
+ * @param f file stream to read from
+ * @param off offset of line inside file
+ * @param dst buffer to read to
+ * @param dstsize size of dst buffer, excluding trailing null
+ * @param skip number of characters to skip
+ * @param ts tab size
+ * @param show_cr show trailing carriage return as ^M
+ *
+ * @return negative on error, otherwise number of bytes except padding
+ */
+
+static int
+cvt_fget (FBUF * f, off_t off, char *dst, size_t dstsize, int skip, int ts, gboolean show_cr)
+{
+    int base = 0;
+    int old_base = base;
+    size_t amount = dstsize;
+    size_t useful, offset;
+    size_t i;
+    size_t sz;
+    int lastch = '\0';
+    const char *q = NULL;
+    char tmp[BUFSIZ];           /* XXX capacity must be >= MAX{dstsize + 1, amount} */
+    char cvt[BUFSIZ];           /* XXX capacity must be >= MAX_TAB_WIDTH * amount */
+
+    if (sizeof (tmp) < amount || sizeof (tmp) <= dstsize || sizeof (cvt) < 8 * amount)
+    {
+        /* abnormal, but avoid buffer overflow */
+        memset (dst, ' ', dstsize);
+        dst[dstsize] = '\0';
+        return 0;
+    }
+
+    f_seek (f, off, SEEK_SET);
+
+    while (skip > base)
+    {
+        old_base = base;
+        sz = f_gets (tmp, amount, f);
+        if (sz == 0)
+            break;
+
+        base = cvt_cpy (cvt, tmp, sz, old_base, ts);
+        if (cvt[base - old_base - 1] == '\n')
+        {
+            q = &cvt[base - old_base - 1];
+            base = old_base + q - cvt + 1;
+            break;
+        }
+    }
+
+    if (base < skip)
+    {
+        memset (dst, ' ', dstsize);
+        dst[dstsize] = '\0';
+        return 0;
+    }
+
+    useful = base - skip;
+    offset = skip - old_base;
+
+    if (useful <= dstsize)
+    {
+        if (useful != 0)
+            memmove (dst, cvt + offset, useful);
+
+        if (q == NULL)
+        {
+            sz = f_gets (tmp, dstsize - useful + 1, f);
+            if (sz != 0)
+            {
+                const char *ptr = tmp;
+
+                useful += cvt_ncpy (dst + useful, dstsize - useful, &ptr, sz, base, ts) - base;
+                if (ptr < tmp + sz)
+                    lastch = *ptr;
+            }
+        }
+        sz = useful;
+    }
+    else
+    {
+        memmove (dst, cvt + offset, dstsize);
+        sz = dstsize;
+        lastch = cvt[offset + dstsize];
+    }
+
+    dst[sz] = lastch;
+    for (i = 0; i < sz && dst[i] != '\n'; i++)
+    {
+        if (dst[i] == '\r' && dst[i + 1] == '\n')
+        {
+            if (show_cr)
+            {
+                if (i + 1 < dstsize)
+                {
+                    dst[i++] = '^';
+                    dst[i++] = 'M';
+                }
+                else
+                {
+                    dst[i++] = '*';
+                }
+            }
+            break;
+        }
+    }
+
+    for (; i < dstsize; i++)
+        dst[i] = ' ';
+    dst[i] = '\0';
+    return sz;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/* diff printers et al ****************************************************** */
+
+static void
+cc_free_elt (void *elt)
+{
+    DIFFLN *p = elt;
+
+    if (p != NULL)
+        g_free (p->p);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+printer (void *ctx, int ch, int line, off_t off, size_t sz, const char *str)
+{
+    GArray *a = ((PRINTER_CTX *) ctx)->a;
+    DSRC dsrc = ((PRINTER_CTX *) ctx)->dsrc;
+
+    if (ch != 0)
+    {
+        DIFFLN p;
+
+        p.p = NULL;
+        p.ch = ch;
+        p.line = line;
+        p.u.off = off;
+        if (dsrc == DATA_SRC_MEM && line != 0)
+        {
+            if (sz != 0 && str[sz - 1] == '\n')
+                sz--;
+            if (sz > 0)
+                p.p = g_strndup (str, sz);
+            p.u.len = sz;
+        }
+        g_array_append_val (a, p);
+    }
+    else if (dsrc == DATA_SRC_MEM)
+    {
+        DIFFLN *p;
+
+        p = &g_array_index (a, DIFFLN, a->len - 1);
+        if (sz != 0 && str[sz - 1] == '\n')
+            sz--;
+        if (sz != 0)
+        {
+            size_t new_size;
+            char *q;
+
+            new_size = p->u.len + sz;
+            q = g_realloc (p->p, new_size);
+            memcpy (q + p->u.len, str, sz);
+            p->p = q;
+        }
+        p->u.len += sz;
+    }
+    if (dsrc == DATA_SRC_TMP && (line != 0 || ch == 0))
+    {
+        FBUF *f = ((PRINTER_CTX *) ctx)->f;
+        f_write (f, str, sz);
+    }
+    return 0;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+redo_diff (WDiff * dview)
+{
+    FBUF *const *f = dview->f;
+    PRINTER_CTX ctx;
+    GArray *ops;
+    int ndiff;
+    int rv;
+    char extra[256];
+
+    extra[0] = '\0';
+    if (dview->opt.quality == 2)
+        strcat (extra, " -d");
+    if (dview->opt.quality == 1)
+        strcat (extra, " --speed-large-files");
+    if (dview->opt.strip_trailing_cr)
+        strcat (extra, " --strip-trailing-cr");
+    if (dview->opt.ignore_tab_expansion)
+        strcat (extra, " -E");
+    if (dview->opt.ignore_space_change)
+        strcat (extra, " -b");
+    if (dview->opt.ignore_all_space)
+        strcat (extra, " -w");
+    if (dview->opt.ignore_case)
+        strcat (extra, " -i");
+
+    if (dview->dsrc != DATA_SRC_MEM)
+    {
+        f_reset (f[DIFF_LEFT]);
+        f_reset (f[DIFF_RIGHT]);
+    }
+
+    ops = g_array_new (FALSE, FALSE, sizeof (DIFFCMD));
+    ndiff = dff_execute (dview->args, extra, dview->file[DIFF_LEFT], dview->file[DIFF_RIGHT], ops);
+    if (ndiff < 0)
+    {
+        if (ops != NULL)
+            g_array_free (ops, TRUE);
+        return -1;
+    }
+
+    ctx.dsrc = dview->dsrc;
+
+    rv = 0;
+    ctx.a = dview->a[DIFF_LEFT];
+    ctx.f = f[DIFF_LEFT];
+    rv |= dff_reparse (DIFF_LEFT, dview->file[DIFF_LEFT], ops, printer, &ctx);
+
+    ctx.a = dview->a[DIFF_RIGHT];
+    ctx.f = f[DIFF_RIGHT];
+    rv |= dff_reparse (DIFF_RIGHT, dview->file[DIFF_RIGHT], ops, printer, &ctx);
+
+    if (ops != NULL)
+        g_array_free (ops, TRUE);
+
+    if (rv != 0 || dview->a[DIFF_LEFT]->len != dview->a[DIFF_RIGHT]->len)
+        return -1;
+
+    if (dview->dsrc == DATA_SRC_TMP)
+    {
+        f_trunc (f[DIFF_LEFT]);
+        f_trunc (f[DIFF_RIGHT]);
+    }
+
+    if (dview->dsrc == DATA_SRC_MEM && HDIFF_ENABLE)
+    {
+        dview->hdiff = g_ptr_array_new ();
+        if (dview->hdiff != NULL)
+        {
+            size_t i;
+
+            for (i = 0; i < dview->a[DIFF_LEFT]->len; i++)
+            {
+                GArray *h = NULL;
+                const DIFFLN *p;
+                const DIFFLN *q;
+
+                p = &g_array_index (dview->a[DIFF_LEFT], DIFFLN, i);
+                q = &g_array_index (dview->a[DIFF_RIGHT], DIFFLN, i);
+                if (p->line && q->line && p->ch == CHG_CH)
+                {
+                    h = g_array_new (FALSE, FALSE, sizeof (BRACKET));
+                    if (h != NULL)
+                    {
+                        gboolean runresult;
+
+                        runresult =
+                            hdiff_scan (p->p, p->u.len, q->p, q->u.len, HDIFF_MINCTX, h,
+                                        HDIFF_DEPTH);
+                        if (!runresult)
+                        {
+                            g_array_free (h, TRUE);
+                            h = NULL;
+                        }
+                    }
+                }
+                g_ptr_array_add (dview->hdiff, h);
+            }
+        }
+    }
+    return ndiff;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+destroy_hdiff (WDiff * dview)
+{
+    if (dview->hdiff != NULL)
+    {
+        int i;
+        int len;
+
+        len = dview->a[DIFF_LEFT]->len;
+
+        for (i = 0; i < len; i++)
+        {
+            GArray *h;
+
+            h = (GArray *) g_ptr_array_index (dview->hdiff, i);
+            if (h != NULL)
+                g_array_free (h, TRUE);
+        }
+        g_ptr_array_free (dview->hdiff, TRUE);
+        dview->hdiff = NULL;
+    }
+
+    mc_search_free (dview->search.handle);
+    dview->search.handle = NULL;
+    MC_PTR_FREE (dview->search.last_string);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/* stuff ******************************************************************** */
+
+static int
+get_digits (unsigned int n)
+{
+    int d = 1;
+
+    while (n /= 10)
+        d++;
+    return d;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+get_line_numbers (const GArray * a, size_t pos, int *linenum, int *lineofs)
+{
+    const DIFFLN *p;
+
+    *linenum = 0;
+    *lineofs = 0;
+
+    if (a->len != 0)
+    {
+        if (pos >= a->len)
+            pos = a->len - 1;
+
+        p = &g_array_index (a, DIFFLN, pos);
+
+        if (p->line == 0)
+        {
+            int n;
+
+            for (n = pos; n > 0; n--)
+            {
+                p--;
+                if (p->line != 0)
+                    break;
+            }
+            *lineofs = pos - n + 1;
+        }
+
+        *linenum = p->line;
+    }
+    return 0;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+calc_nwidth (const GArray * const *a)
+{
+    int l1, o1;
+    int l2, o2;
+
+    get_line_numbers (a[DIFF_LEFT], a[DIFF_LEFT]->len - 1, &l1, &o1);
+    get_line_numbers (a[DIFF_RIGHT], a[DIFF_RIGHT]->len - 1, &l2, &o2);
+    if (l1 < l2)
+        l1 = l2;
+    return get_digits (l1);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+find_prev_hunk (const GArray * a, int pos)
+{
+#if 1
+    while (pos > 0 && ((DIFFLN *) & g_array_index (a, DIFFLN, pos))->ch != EQU_CH)
+        pos--;
+    while (pos > 0 && ((DIFFLN *) & g_array_index (a, DIFFLN, pos))->ch == EQU_CH)
+        pos--;
+    while (pos > 0 && ((DIFFLN *) & g_array_index (a, DIFFLN, pos))->ch != EQU_CH)
+        pos--;
+    if (pos > 0 && (size_t) pos < a->len)
+        pos++;
+#else
+    while (pos > 0 && ((DIFFLN *) & g_array_index (a, DIFFLN, pos - 1))->ch == EQU_CH)
+        pos--;
+    while (pos > 0 && ((DIFFLN *) & g_array_index (a, DIFFLN, pos - 1))->ch != EQU_CH)
+        pos--;
+#endif
+
+    return pos;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static size_t
+find_next_hunk (const GArray * a, size_t pos)
+{
+    while (pos < a->len && ((DIFFLN *) & g_array_index (a, DIFFLN, pos))->ch != EQU_CH)
+        pos++;
+    while (pos < a->len && ((DIFFLN *) & g_array_index (a, DIFFLN, pos))->ch == EQU_CH)
+        pos++;
+    return pos;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Find start and end lines of the current hunk.
+ *
+ * @param dview WDiff widget
+ * @return boolean and
+ * start_line1 first line of current hunk (file[0])
+ * end_line1 last line of current hunk (file[0])
+ * start_line1 first line of current hunk (file[0])
+ * end_line1 last line of current hunk (file[0])
+ */
+
+static int
+get_current_hunk (WDiff * dview, int *start_line1, int *end_line1, int *start_line2, int *end_line2)
+{
+    const GArray *a0 = dview->a[DIFF_LEFT];
+    const GArray *a1 = dview->a[DIFF_RIGHT];
+    size_t pos;
+    int ch;
+    int res = 0;
+
+    *start_line1 = 1;
+    *start_line2 = 1;
+    *end_line1 = 1;
+    *end_line2 = 1;
+
+    pos = dview->skip_rows;
+    ch = ((DIFFLN *) & g_array_index (a0, DIFFLN, pos))->ch;
+    if (ch != EQU_CH)
+    {
+        switch (ch)
+        {
+        case ADD_CH:
+            res = DIFF_DEL;
+            break;
+        case DEL_CH:
+            res = DIFF_ADD;
+            break;
+        case CHG_CH:
+            res = DIFF_CHG;
+            break;
+        default:
+            break;
+        }
+        while (pos > 0 && ((DIFFLN *) & g_array_index (a0, DIFFLN, pos))->ch != EQU_CH)
+            pos--;
+        if (pos > 0)
+        {
+            *start_line1 = ((DIFFLN *) & g_array_index (a0, DIFFLN, pos))->line + 1;
+            *start_line2 = ((DIFFLN *) & g_array_index (a1, DIFFLN, pos))->line + 1;
+        }
+        pos = dview->skip_rows;
+        while (pos < a0->len && ((DIFFLN *) & g_array_index (a0, DIFFLN, pos))->ch != EQU_CH)
+        {
+            int l0, l1;
+
+            l0 = ((DIFFLN *) & g_array_index (a0, DIFFLN, pos))->line;
+            l1 = ((DIFFLN *) & g_array_index (a1, DIFFLN, pos))->line;
+            if (l0 > 0)
+                *end_line1 = MAX (*start_line1, l0);
+            if (l1 > 0)
+                *end_line2 = MAX (*start_line2, l1);
+            pos++;
+        }
+    }
+    return res;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Remove hunk from file.
+ *
+ * @param dview           WDiff widget
+ * @param merge_file      file stream for writing data
+ * @param from1           first line of hunk
+ * @param to1             last line of hunk
+ * @param merge_direction in what direction files should be merged
+ */
+
+static void
+dview_remove_hunk (WDiff * dview, FILE * merge_file, int from1, int to1,
+                   action_direction_t merge_direction)
+{
+    int line;
+    char buf[BUF_10K];
+    FILE *f0;
+
+    if (merge_direction == FROM_RIGHT_TO_LEFT)
+        f0 = fopen (dview->file[DIFF_RIGHT], "r");
+    else
+        f0 = fopen (dview->file[DIFF_LEFT], "r");
+
+    line = 0;
+    while (fgets (buf, sizeof (buf), f0) != NULL && line < from1 - 1)
+    {
+        line++;
+        fputs (buf, merge_file);
+    }
+    while (fgets (buf, sizeof (buf), f0) != NULL)
+    {
+        line++;
+        if (line >= to1)
+            fputs (buf, merge_file);
+    }
+    fclose (f0);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Add hunk to file.
+ *
+ * @param dview           WDiff widget
+ * @param merge_file      file stream for writing data
+ * @param from1           first line of source hunk
+ * @param from2           first line of destination hunk
+ * @param to1             last line of source hunk
+ * @param merge_direction in what direction files should be merged
+ */
+
+static void
+dview_add_hunk (WDiff * dview, FILE * merge_file, int from1, int from2, int to2,
+                action_direction_t merge_direction)
+{
+    int line;
+    char buf[BUF_10K];
+    FILE *f0;
+    FILE *f1;
+
+    if (merge_direction == FROM_RIGHT_TO_LEFT)
+    {
+        f0 = fopen (dview->file[DIFF_RIGHT], "r");
+        f1 = fopen (dview->file[DIFF_LEFT], "r");
+    }
+    else
+    {
+        f0 = fopen (dview->file[DIFF_LEFT], "r");
+        f1 = fopen (dview->file[DIFF_RIGHT], "r");
+    }
+
+    line = 0;
+    while (fgets (buf, sizeof (buf), f0) != NULL && line < from1 - 1)
+    {
+        line++;
+        fputs (buf, merge_file);
+    }
+    line = 0;
+    while (fgets (buf, sizeof (buf), f1) != NULL && line <= to2)
+    {
+        line++;
+        if (line >= from2)
+            fputs (buf, merge_file);
+    }
+    while (fgets (buf, sizeof (buf), f0) != NULL)
+        fputs (buf, merge_file);
+
+    fclose (f0);
+    fclose (f1);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Replace hunk in file.
+ *
+ * @param dview           WDiff widget
+ * @param merge_file      file stream for writing data
+ * @param from1           first line of source hunk
+ * @param to1             last line of source hunk
+ * @param from2           first line of destination hunk
+ * @param to2             last line of destination hunk
+ * @param merge_direction in what direction files should be merged
+ */
+
+static void
+dview_replace_hunk (WDiff * dview, FILE * merge_file, int from1, int to1, int from2, int to2,
+                    action_direction_t merge_direction)
+{
+    int line1 = 0, line2 = 0;
+    char buf[BUF_10K];
+    FILE *f0;
+    FILE *f1;
+
+    if (merge_direction == FROM_RIGHT_TO_LEFT)
+    {
+        f0 = fopen (dview->file[DIFF_RIGHT], "r");
+        f1 = fopen (dview->file[DIFF_LEFT], "r");
+    }
+    else
+    {
+        f0 = fopen (dview->file[DIFF_LEFT], "r");
+        f1 = fopen (dview->file[DIFF_RIGHT], "r");
+    }
+
+    while (fgets (buf, sizeof (buf), f0) != NULL && line1 < from1 - 1)
+    {
+        line1++;
+        fputs (buf, merge_file);
+    }
+    while (fgets (buf, sizeof (buf), f1) != NULL && line2 <= to2)
+    {
+        line2++;
+        if (line2 >= from2)
+            fputs (buf, merge_file);
+    }
+    while (fgets (buf, sizeof (buf), f0) != NULL)
+    {
+        line1++;
+        if (line1 > to1)
+            fputs (buf, merge_file);
+    }
+    fclose (f0);
+    fclose (f1);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Merge hunk.
+ *
+ * @param dview           WDiff widget
+ * @param merge_direction in what direction files should be merged
+ */
+
+static void
+do_merge_hunk (WDiff * dview, action_direction_t merge_direction)
+{
+    int from1, to1, from2, to2;
+    int hunk;
+    diff_place_t n_merge = (merge_direction == FROM_RIGHT_TO_LEFT) ? DIFF_RIGHT : DIFF_LEFT;
+
+    if (merge_direction == FROM_RIGHT_TO_LEFT)
+        hunk = get_current_hunk (dview, &from2, &to2, &from1, &to1);
+    else
+        hunk = get_current_hunk (dview, &from1, &to1, &from2, &to2);
+
+    if (hunk > 0)
+    {
+        int merge_file_fd;
+        FILE *merge_file;
+        vfs_path_t *merge_file_name_vpath = NULL;
+
+        if (!dview->merged[n_merge])
+        {
+            dview->merged[n_merge] = mc_util_make_backup_if_possible (dview->file[n_merge], "~~~");
+            if (!dview->merged[n_merge])
+            {
+                message (D_ERROR, MSG_ERROR,
+                         _("Cannot create backup file\n%s%s\n%s"),
+                         dview->file[n_merge], "~~~", unix_error_string (errno));
+                return;
+            }
+        }
+
+        merge_file_fd = mc_mkstemps (&merge_file_name_vpath, "mcmerge", NULL);
+        if (merge_file_fd == -1)
+        {
+            message (D_ERROR, MSG_ERROR, _("Cannot create temporary merge file\n%s"),
+                     unix_error_string (errno));
+            return;
+        }
+
+        merge_file = fdopen (merge_file_fd, "w");
+
+        switch (hunk)
+        {
+        case DIFF_DEL:
+            if (merge_direction == FROM_RIGHT_TO_LEFT)
+                dview_add_hunk (dview, merge_file, from1, from2, to2, FROM_RIGHT_TO_LEFT);
+            else
+                dview_remove_hunk (dview, merge_file, from1, to1, FROM_LEFT_TO_RIGHT);
+            break;
+        case DIFF_ADD:
+            if (merge_direction == FROM_RIGHT_TO_LEFT)
+                dview_remove_hunk (dview, merge_file, from1, to1, FROM_RIGHT_TO_LEFT);
+            else
+                dview_add_hunk (dview, merge_file, from1, from2, to2, FROM_LEFT_TO_RIGHT);
+            break;
+        case DIFF_CHG:
+            dview_replace_hunk (dview, merge_file, from1, to1, from2, to2, merge_direction);
+            break;
+        default:
+            break;
+        }
+        fflush (merge_file);
+        fclose (merge_file);
+        {
+            int res;
+
+            res = rewrite_backup_content (merge_file_name_vpath, dview->file[n_merge]);
+            (void) res;
+        }
+        mc_unlink (merge_file_name_vpath);
+        vfs_path_free (merge_file_name_vpath, TRUE);
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/* view routines and callbacks ********************************************** */
+
+static void
+dview_compute_split (WDiff * dview, int i)
+{
+    dview->bias += i;
+    if (dview->bias < 2 - dview->half1)
+        dview->bias = 2 - dview->half1;
+    if (dview->bias > dview->half2 - 2)
+        dview->bias = dview->half2 - 2;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_compute_areas (WDiff * dview)
+{
+    Widget *w = WIDGET (dview);
+
+    dview->height = w->rect.lines - 1;
+    dview->half1 = w->rect.cols / 2;
+    dview->half2 = w->rect.cols - dview->half1;
+
+    dview_compute_split (dview, 0);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_reread (WDiff * dview)
+{
+    int ndiff;
+
+    destroy_hdiff (dview);
+    if (dview->a[DIFF_LEFT] != NULL)
+    {
+        g_array_foreach (dview->a[DIFF_LEFT], DIFFLN, cc_free_elt);
+        g_array_free (dview->a[DIFF_LEFT], TRUE);
+    }
+    if (dview->a[DIFF_RIGHT] != NULL)
+    {
+        g_array_foreach (dview->a[DIFF_RIGHT], DIFFLN, cc_free_elt);
+        g_array_free (dview->a[DIFF_RIGHT], TRUE);
+    }
+
+    dview->a[DIFF_LEFT] = g_array_new (FALSE, FALSE, sizeof (DIFFLN));
+    dview->a[DIFF_RIGHT] = g_array_new (FALSE, FALSE, sizeof (DIFFLN));
+
+    ndiff = redo_diff (dview);
+    if (ndiff >= 0)
+        dview->ndiff = ndiff;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+#ifdef HAVE_CHARSET
+static void
+dview_set_codeset (WDiff * dview)
+{
+    const char *encoding_id = NULL;
+
+    dview->utf8 = TRUE;
+    encoding_id =
+        get_codepage_id (mc_global.source_codepage >=
+                         0 ? mc_global.source_codepage : mc_global.display_codepage);
+    if (encoding_id != NULL)
+    {
+        GIConv conv;
+
+        conv = str_crt_conv_from (encoding_id);
+        if (conv != INVALID_CONV)
+        {
+            if (dview->converter != str_cnv_from_term)
+                str_close_conv (dview->converter);
+            dview->converter = conv;
+        }
+        dview->utf8 = (gboolean) str_isutf8 (encoding_id);
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_select_encoding (WDiff * dview)
+{
+    if (do_select_codepage ())
+        dview_set_codeset (dview);
+    dview_reread (dview);
+    tty_touch_screen ();
+    repaint_screen ();
+}
+#endif /* HAVE_CHARSET */
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_diff_options (WDiff * dview)
+{
+    const char *quality_str[] = {
+        N_("No&rmal"),
+        N_("&Fastest (Assume large files)"),
+        N_("&Minimal (Find a smaller set of change)")
+    };
+
+    quick_widget_t quick_widgets[] = {
+        /* *INDENT-OFF* */
+        QUICK_START_GROUPBOX (N_("Diff algorithm")),
+            QUICK_RADIO (3, (const char **) quality_str, (int *) &dview->opt.quality, NULL),
+        QUICK_STOP_GROUPBOX,
+        QUICK_START_GROUPBOX (N_("Diff extra options")),
+            QUICK_CHECKBOX (N_("&Ignore case"), &dview->opt.ignore_case, NULL),
+            QUICK_CHECKBOX (N_("Ignore tab &expansion"), &dview->opt.ignore_tab_expansion, NULL),
+            QUICK_CHECKBOX (N_("Ignore &space change"), &dview->opt.ignore_space_change, NULL),
+            QUICK_CHECKBOX (N_("Ignore all &whitespace"), &dview->opt.ignore_all_space, NULL),
+            QUICK_CHECKBOX (N_("Strip &trailing carriage return"), &dview->opt.strip_trailing_cr,
+                            NULL),
+        QUICK_STOP_GROUPBOX,
+        QUICK_BUTTONS_OK_CANCEL,
+        QUICK_END
+        /* *INDENT-ON* */
+    };
+
+    WRect r = { -1, -1, 0, 56 };
+
+    quick_dialog_t qdlg = {
+        r, N_("Diff Options"), "[Diff Options]",
+        quick_widgets, NULL, NULL
+    };
+
+    if (quick_dialog (&qdlg) != B_CANCEL)
+        dview_reread (dview);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+dview_init (WDiff * dview, const char *args, const char *file1, const char *file2,
+            const char *label1, const char *label2, DSRC dsrc)
+{
+    int ndiff;
+    FBUF *f[DIFF_COUNT];
+
+    f[DIFF_LEFT] = NULL;
+    f[DIFF_RIGHT] = NULL;
+
+    if (dsrc == DATA_SRC_TMP)
+    {
+        f[DIFF_LEFT] = f_temp ();
+        if (f[DIFF_LEFT] == NULL)
+            return -1;
+
+        f[DIFF_RIGHT] = f_temp ();
+        if (f[DIFF_RIGHT] == NULL)
+        {
+            f_close (f[DIFF_LEFT]);
+            return -1;
+        }
+    }
+    else if (dsrc == DATA_SRC_ORG)
+    {
+        f[DIFF_LEFT] = f_open (file1, O_RDONLY);
+        if (f[DIFF_LEFT] == NULL)
+            return -1;
+
+        f[DIFF_RIGHT] = f_open (file2, O_RDONLY);
+        if (f[DIFF_RIGHT] == NULL)
+        {
+            f_close (f[DIFF_LEFT]);
+            return -1;
+        }
+    }
+
+    dview->args = args;
+    dview->file[DIFF_LEFT] = file1;
+    dview->file[DIFF_RIGHT] = file2;
+    dview->label[DIFF_LEFT] = g_strdup (label1);
+    dview->label[DIFF_RIGHT] = g_strdup (label2);
+    dview->f[DIFF_LEFT] = f[0];
+    dview->f[DIFF_RIGHT] = f[1];
+    dview->merged[DIFF_LEFT] = FALSE;
+    dview->merged[DIFF_RIGHT] = FALSE;
+    dview->hdiff = NULL;
+    dview->dsrc = dsrc;
+#ifdef HAVE_CHARSET
+    dview->converter = str_cnv_from_term;
+    dview_set_codeset (dview);
+#endif
+    dview->a[DIFF_LEFT] = g_array_new (FALSE, FALSE, sizeof (DIFFLN));
+    dview->a[DIFF_RIGHT] = g_array_new (FALSE, FALSE, sizeof (DIFFLN));
+
+    ndiff = redo_diff (dview);
+    if (ndiff < 0)
+    {
+        /* goto MSG_DESTROY stage: dview_fini() */
+        f_close (f[DIFF_LEFT]);
+        f_close (f[DIFF_RIGHT]);
+        return -1;
+    }
+
+    dview->ndiff = ndiff;
+
+    dview->view_quit = FALSE;
+
+    dview->bias = 0;
+    dview->new_frame = TRUE;
+    dview->skip_rows = 0;
+    dview->skip_cols = 0;
+    dview->display_symbols = 0;
+    dview->display_numbers = 0;
+    dview->show_cr = TRUE;
+    dview->tab_size = 8;
+    dview->ord = DIFF_LEFT;
+    dview->full = FALSE;
+
+    dview->search.handle = NULL;
+    dview->search.last_string = NULL;
+    dview->search.last_found_line = -1;
+    dview->search.last_accessed_num_line = -1;
+
+    dview->opt.quality = 0;
+    dview->opt.strip_trailing_cr = 0;
+    dview->opt.ignore_tab_expansion = 0;
+    dview->opt.ignore_space_change = 0;
+    dview->opt.ignore_all_space = 0;
+    dview->opt.ignore_case = 0;
+
+    dview_compute_areas (dview);
+
+    return 0;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_fini (WDiff * dview)
+{
+    if (dview->dsrc != DATA_SRC_MEM)
+    {
+        f_close (dview->f[DIFF_RIGHT]);
+        f_close (dview->f[DIFF_LEFT]);
+    }
+
+#ifdef HAVE_CHARSET
+    if (dview->converter != str_cnv_from_term)
+        str_close_conv (dview->converter);
+#endif
+
+    destroy_hdiff (dview);
+    if (dview->a[DIFF_LEFT] != NULL)
+    {
+        g_array_foreach (dview->a[DIFF_LEFT], DIFFLN, cc_free_elt);
+        g_array_free (dview->a[DIFF_LEFT], TRUE);
+        dview->a[DIFF_LEFT] = NULL;
+    }
+    if (dview->a[DIFF_RIGHT] != NULL)
+    {
+        g_array_foreach (dview->a[DIFF_RIGHT], DIFFLN, cc_free_elt);
+        g_array_free (dview->a[DIFF_RIGHT], TRUE);
+        dview->a[DIFF_RIGHT] = NULL;
+    }
+
+    g_free (dview->label[DIFF_LEFT]);
+    g_free (dview->label[DIFF_RIGHT]);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+dview_display_file (const WDiff * dview, diff_place_t ord, int r, int c, int height, int width)
+{
+    size_t i, k;
+    int j;
+    char buf[BUFSIZ];
+    FBUF *f = dview->f[ord];
+    int skip = dview->skip_cols;
+    int display_symbols = dview->display_symbols;
+    int display_numbers = dview->display_numbers;
+    gboolean show_cr = dview->show_cr;
+    int tab_size = 8;
+    const DIFFLN *p;
+    int nwidth = display_numbers;
+    int xwidth;
+
+    xwidth = display_symbols + display_numbers;
+    if (dview->tab_size > 0 && dview->tab_size < 9)
+        tab_size = dview->tab_size;
+
+    if (xwidth != 0)
+    {
+        if (xwidth > width && display_symbols)
+        {
+            xwidth--;
+            display_symbols = 0;
+        }
+        if (xwidth > width && display_numbers)
+        {
+            xwidth = width;
+            display_numbers = width;
+        }
+
+        xwidth++;
+        c += xwidth;
+        width -= xwidth;
+        if (width < 0)
+            width = 0;
+    }
+
+    if ((int) sizeof (buf) <= width || (int) sizeof (buf) <= nwidth)
+    {
+        /* abnormal, but avoid buffer overflow */
+        return -1;
+    }
+
+    for (i = dview->skip_rows, j = 0; i < dview->a[ord]->len && j < height; j++, i++)
+    {
+        int ch, next_ch = 0, col;
+        size_t cnt;
+
+        p = (DIFFLN *) & g_array_index (dview->a[ord], DIFFLN, i);
+        ch = p->ch;
+        tty_setcolor (NORMAL_COLOR);
+        if (display_symbols)
+        {
+            tty_gotoyx (r + j, c - 2);
+            tty_print_char (ch);
+        }
+        if (p->line != 0)
+        {
+            if (display_numbers)
+            {
+                tty_gotoyx (r + j, c - xwidth);
+                g_snprintf (buf, display_numbers + 1, "%*d", nwidth, p->line);
+                tty_print_string (str_fit_to_term (buf, nwidth, J_LEFT_FIT));
+            }
+            if (ch == ADD_CH)
+                tty_setcolor (DFF_ADD_COLOR);
+            if (ch == CHG_CH)
+                tty_setcolor (DFF_CHG_COLOR);
+            if (f == NULL)
+            {
+                if (i == (size_t) dview->search.last_found_line)
+                    tty_setcolor (MARKED_SELECTED_COLOR);
+                else if (dview->hdiff != NULL && g_ptr_array_index (dview->hdiff, i) != NULL)
+                {
+                    char att[BUFSIZ];
+
+#ifdef HAVE_CHARSET
+                    if (dview->utf8)
+                        k = dview_str_utf8_offset_to_pos (p->p, width);
+                    else
+#endif
+                        k = width;
+
+                    cvt_mgeta (p->p, p->u.len, buf, k, skip, tab_size, show_cr,
+                               g_ptr_array_index (dview->hdiff, i), ord, att);
+                    tty_gotoyx (r + j, c);
+                    col = 0;
+
+                    for (cnt = 0; cnt < strlen (buf) && col < width; cnt++)
+                    {
+                        gboolean ch_res;
+
+#ifdef HAVE_CHARSET
+                        if (dview->utf8)
+                        {
+                            int ch_length = 0;
+
+                            ch_res = dview_get_utf (buf + cnt, &next_ch, &ch_length);
+                            if (ch_length > 1)
+                                cnt += ch_length - 1;
+                            if (!g_unichar_isprint (next_ch))
+                                next_ch = '.';
+                        }
+                        else
+#endif
+                            ch_res = dview_get_byte (buf + cnt, &next_ch);
+
+                        if (ch_res)
+                        {
+                            tty_setcolor (att[cnt] ? DFF_CHH_COLOR : DFF_CHG_COLOR);
+#ifdef HAVE_CHARSET
+                            if (mc_global.utf8_display)
+                            {
+                                if (!dview->utf8)
+                                {
+                                    next_ch =
+                                        convert_from_8bit_to_utf_c ((unsigned char) next_ch,
+                                                                    dview->converter);
+                                }
+                            }
+                            else if (dview->utf8)
+                                next_ch = convert_from_utf_to_current_c (next_ch, dview->converter);
+                            else
+                                next_ch = convert_to_display_c (next_ch);
+#endif
+                            tty_print_anychar (next_ch);
+                            col++;
+                        }
+                    }
+                    continue;
+                }
+
+                if (ch == CHG_CH)
+                    tty_setcolor (DFF_CHH_COLOR);
+
+#ifdef HAVE_CHARSET
+                if (dview->utf8)
+                    k = dview_str_utf8_offset_to_pos (p->p, width);
+                else
+#endif
+                    k = width;
+                cvt_mget (p->p, p->u.len, buf, k, skip, tab_size, show_cr);
+            }
+            else
+                cvt_fget (f, p->u.off, buf, width, skip, tab_size, show_cr);
+        }
+        else
+        {
+            if (display_numbers)
+            {
+                tty_gotoyx (r + j, c - xwidth);
+                memset (buf, ' ', display_numbers);
+                buf[display_numbers] = '\0';
+                tty_print_string (buf);
+            }
+            if (ch == DEL_CH)
+                tty_setcolor (DFF_DEL_COLOR);
+            if (ch == CHG_CH)
+                tty_setcolor (DFF_CHD_COLOR);
+            memset (buf, ' ', width);
+            buf[width] = '\0';
+        }
+        tty_gotoyx (r + j, c);
+        /* tty_print_nstring (buf, width); */
+        col = 0;
+        for (cnt = 0; cnt < strlen (buf) && col < width; cnt++)
+        {
+            gboolean ch_res;
+
+#ifdef HAVE_CHARSET
+            if (dview->utf8)
+            {
+                int ch_length = 0;
+
+                ch_res = dview_get_utf (buf + cnt, &next_ch, &ch_length);
+                if (ch_length > 1)
+                    cnt += ch_length - 1;
+                if (!g_unichar_isprint (next_ch))
+                    next_ch = '.';
+            }
+            else
+#endif
+                ch_res = dview_get_byte (buf + cnt, &next_ch);
+
+            if (ch_res)
+            {
+#ifdef HAVE_CHARSET
+                if (mc_global.utf8_display)
+                {
+                    if (!dview->utf8)
+                    {
+                        next_ch =
+                            convert_from_8bit_to_utf_c ((unsigned char) next_ch, dview->converter);
+                    }
+                }
+                else if (dview->utf8)
+                    next_ch = convert_from_utf_to_current_c (next_ch, dview->converter);
+                else
+                    next_ch = convert_to_display_c (next_ch);
+#endif
+
+                tty_print_anychar (next_ch);
+                col++;
+            }
+        }
+    }
+    tty_setcolor (NORMAL_COLOR);
+    k = width;
+    if (width < xwidth - 1)
+        k = xwidth - 1;
+    memset (buf, ' ', k);
+    buf[k] = '\0';
+    for (; j < height; j++)
+    {
+        if (xwidth != 0)
+        {
+            tty_gotoyx (r + j, c - xwidth);
+            /* tty_print_nstring (buf, xwidth - 1); */
+            tty_print_string (str_fit_to_term (buf, xwidth - 1, J_LEFT_FIT));
+        }
+        tty_gotoyx (r + j, c);
+        /* tty_print_nstring (buf, width); */
+        tty_print_string (str_fit_to_term (buf, width, J_LEFT_FIT));
+    }
+
+    return 0;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_status (const WDiff * dview, diff_place_t ord, int width, int c)
+{
+    const char *buf;
+    int filename_width;
+    int linenum, lineofs;
+    vfs_path_t *vpath;
+    char *path;
+
+    tty_setcolor (STATUSBAR_COLOR);
+
+    tty_gotoyx (0, c);
+    get_line_numbers (dview->a[ord], dview->skip_rows, &linenum, &lineofs);
+
+    filename_width = width - 24;
+    if (filename_width < 8)
+        filename_width = 8;
+
+    vpath = vfs_path_from_str (dview->label[ord]);
+    path = vfs_path_to_str_flags (vpath, 0, VPF_STRIP_HOME | VPF_STRIP_PASSWORD);
+    vfs_path_free (vpath, TRUE);
+    buf = str_term_trim (path, filename_width);
+    if (ord == DIFF_LEFT)
+        tty_printf ("%s%-*s %6d+%-4d Col %-4d ", dview->merged[ord] ? "* " : "  ", filename_width,
+                    buf, linenum, lineofs, dview->skip_cols);
+    else
+        tty_printf ("%s%-*s %6d+%-4d Dif %-4d ", dview->merged[ord] ? "* " : "  ", filename_width,
+                    buf, linenum, lineofs, dview->ndiff);
+    g_free (path);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_redo (WDiff * dview)
+{
+    if (dview->display_numbers)
+    {
+        int old;
+
+        old = dview->display_numbers;
+        dview->display_numbers = calc_nwidth ((const GArray * const *) dview->a);
+        dview->new_frame = (old != dview->display_numbers);
+    }
+    dview_reread (dview);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_update (WDiff * dview)
+{
+    int height = dview->height;
+    int width1;
+    int width2;
+    int last;
+
+    last = dview->a[DIFF_LEFT]->len - 1;
+
+    if (dview->skip_rows > last)
+        dview->skip_rows = dview->search.last_accessed_num_line = last;
+    if (dview->skip_rows < 0)
+        dview->skip_rows = dview->search.last_accessed_num_line = 0;
+    if (dview->skip_cols < 0)
+        dview->skip_cols = 0;
+
+    if (height < 2)
+        return;
+
+    width1 = dview->half1 + dview->bias;
+    width2 = dview->half2 - dview->bias;
+    if (dview->full)
+    {
+        width1 = COLS;
+        width2 = 0;
+    }
+
+    if (dview->new_frame)
+    {
+        int xwidth;
+
+        tty_setcolor (NORMAL_COLOR);
+        xwidth = dview->display_symbols + dview->display_numbers;
+        if (width1 > 1)
+            tty_draw_box (1, 0, height, width1, FALSE);
+        if (width2 > 1)
+            tty_draw_box (1, width1, height, width2, FALSE);
+
+        if (xwidth != 0)
+        {
+            xwidth++;
+            if (xwidth < width1 - 1)
+            {
+                tty_gotoyx (1, xwidth);
+                tty_print_alt_char (ACS_TTEE, FALSE);
+                tty_gotoyx (height, xwidth);
+                tty_print_alt_char (ACS_BTEE, FALSE);
+                tty_draw_vline (2, xwidth, ACS_VLINE, height - 2);
+            }
+            if (xwidth < width2 - 1)
+            {
+                tty_gotoyx (1, width1 + xwidth);
+                tty_print_alt_char (ACS_TTEE, FALSE);
+                tty_gotoyx (height, width1 + xwidth);
+                tty_print_alt_char (ACS_BTEE, FALSE);
+                tty_draw_vline (2, width1 + xwidth, ACS_VLINE, height - 2);
+            }
+        }
+        dview->new_frame = FALSE;
+    }
+
+    if (width1 > 2)
+    {
+        dview_status (dview, dview->ord, width1, 0);
+        dview_display_file (dview, dview->ord, 2, 1, height - 2, width1 - 2);
+    }
+    if (width2 > 2)
+    {
+        dview_status (dview, dview->ord ^ 1, width2, width1);
+        dview_display_file (dview, dview->ord ^ 1, 2, width1 + 1, height - 2, width2 - 2);
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_edit (WDiff * dview, diff_place_t ord)
+{
+    Widget *h;
+    gboolean h_modal;
+    int linenum, lineofs;
+
+    if (dview->dsrc == DATA_SRC_TMP)
+    {
+        error_dialog (_("Edit"), _("Edit is disabled"));
+        return;
+    }
+
+    h = WIDGET (WIDGET (dview)->owner);
+    h_modal = widget_get_state (h, WST_MODAL);
+
+    get_line_numbers (dview->a[ord], dview->skip_rows, &linenum, &lineofs);
+
+    /* disallow edit file in several editors */
+    widget_set_state (h, WST_MODAL, TRUE);
+
+    {
+        vfs_path_t *tmp_vpath;
+
+        tmp_vpath = vfs_path_from_str (dview->file[ord]);
+        edit_file_at_line (tmp_vpath, use_internal_edit, linenum);
+        vfs_path_free (tmp_vpath, TRUE);
+    }
+
+    widget_set_state (h, WST_MODAL, h_modal);
+    dview_redo (dview);
+    dview_update (dview);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_goto_cmd (WDiff * dview, diff_place_t ord)
+{
+    static gboolean first_run = TRUE;
+
+    /* *INDENT-OFF* */
+    static const char *title[2] = {
+        N_("Goto line (left)"),
+        N_("Goto line (right)")
+    };
+    /* *INDENT-ON* */
+
+    int newline;
+    char *input;
+
+    input =
+        input_dialog (_(title[ord]), _("Enter line:"), MC_HISTORY_YDIFF_GOTO_LINE,
+                      first_run ? NULL : INPUT_LAST_TEXT, INPUT_COMPLETE_NONE);
+    if (input != NULL)
+    {
+        const char *s = input;
+
+        if (scan_deci (&s, &newline) == 0 && *s == '\0')
+        {
+            size_t i = 0;
+
+            if (newline > 0)
+            {
+                for (; i < dview->a[ord]->len; i++)
+                {
+                    const DIFFLN *p;
+
+                    p = &g_array_index (dview->a[ord], DIFFLN, i);
+                    if (p->line == newline)
+                        break;
+                }
+            }
+            dview->skip_rows = dview->search.last_accessed_num_line = (ssize_t) i;
+        }
+        g_free (input);
+    }
+
+    first_run = FALSE;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_labels (WDiff * dview)
+{
+    Widget *d = WIDGET (dview);
+    WButtonBar *b;
+
+    b = find_buttonbar (DIALOG (d->owner));
+
+    buttonbar_set_label (b, 1, Q_ ("ButtonBar|Help"), d->keymap, d);
+    buttonbar_set_label (b, 2, Q_ ("ButtonBar|Save"), d->keymap, d);
+    buttonbar_set_label (b, 4, Q_ ("ButtonBar|Edit"), d->keymap, d);
+    buttonbar_set_label (b, 5, Q_ ("ButtonBar|Merge"), d->keymap, d);
+    buttonbar_set_label (b, 7, Q_ ("ButtonBar|Search"), d->keymap, d);
+    buttonbar_set_label (b, 9, Q_ ("ButtonBar|Options"), d->keymap, d);
+    buttonbar_set_label (b, 10, Q_ ("ButtonBar|Quit"), d->keymap, d);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static gboolean
+dview_save (WDiff * dview)
+{
+    gboolean res = TRUE;
+
+    if (dview->merged[DIFF_LEFT])
+    {
+        res = mc_util_unlink_backup_if_possible (dview->file[DIFF_LEFT], "~~~");
+        dview->merged[DIFF_LEFT] = !res;
+    }
+    if (dview->merged[DIFF_RIGHT])
+    {
+        res = mc_util_unlink_backup_if_possible (dview->file[DIFF_RIGHT], "~~~");
+        dview->merged[DIFF_RIGHT] = !res;
+    }
+    return res;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_do_save (WDiff * dview)
+{
+    (void) dview_save (dview);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_save_options (WDiff * dview)
+{
+    mc_config_set_bool (mc_global.main_config, "DiffView", "show_symbols",
+                        dview->display_symbols != 0);
+    mc_config_set_bool (mc_global.main_config, "DiffView", "show_numbers",
+                        dview->display_numbers != 0);
+    mc_config_set_int (mc_global.main_config, "DiffView", "tab_size", dview->tab_size);
+
+    mc_config_set_int (mc_global.main_config, "DiffView", "diff_quality", dview->opt.quality);
+
+    mc_config_set_bool (mc_global.main_config, "DiffView", "diff_ignore_tws",
+                        dview->opt.strip_trailing_cr);
+    mc_config_set_bool (mc_global.main_config, "DiffView", "diff_ignore_all_space",
+                        dview->opt.ignore_all_space);
+    mc_config_set_bool (mc_global.main_config, "DiffView", "diff_ignore_space_change",
+                        dview->opt.ignore_space_change);
+    mc_config_set_bool (mc_global.main_config, "DiffView", "diff_tab_expansion",
+                        dview->opt.ignore_tab_expansion);
+    mc_config_set_bool (mc_global.main_config, "DiffView", "diff_ignore_case",
+                        dview->opt.ignore_case);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_load_options (WDiff * dview)
+{
+    gboolean show_numbers, show_symbols;
+    int tab_size;
+
+    show_symbols = mc_config_get_bool (mc_global.main_config, "DiffView", "show_symbols", FALSE);
+    if (show_symbols)
+        dview->display_symbols = 1;
+    show_numbers = mc_config_get_bool (mc_global.main_config, "DiffView", "show_numbers", FALSE);
+    if (show_numbers)
+        dview->display_numbers = calc_nwidth ((const GArray * const *) dview->a);
+    tab_size = mc_config_get_int (mc_global.main_config, "DiffView", "tab_size", 8);
+    if (tab_size > 0 && tab_size < 9)
+        dview->tab_size = tab_size;
+    else
+        dview->tab_size = 8;
+
+    dview->opt.quality = mc_config_get_int (mc_global.main_config, "DiffView", "diff_quality", 0);
+
+    dview->opt.strip_trailing_cr =
+        mc_config_get_bool (mc_global.main_config, "DiffView", "diff_ignore_tws", FALSE);
+    dview->opt.ignore_all_space =
+        mc_config_get_bool (mc_global.main_config, "DiffView", "diff_ignore_all_space", FALSE);
+    dview->opt.ignore_space_change =
+        mc_config_get_bool (mc_global.main_config, "DiffView", "diff_ignore_space_change", FALSE);
+    dview->opt.ignore_tab_expansion =
+        mc_config_get_bool (mc_global.main_config, "DiffView", "diff_tab_expansion", FALSE);
+    dview->opt.ignore_case =
+        mc_config_get_bool (mc_global.main_config, "DiffView", "diff_ignore_case", FALSE);
+
+    dview->new_frame = TRUE;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+/*
+ * Check if it's OK to close the diff viewer.  If there are unsaved changes,
+ * ask user.
+ */
+static gboolean
+dview_ok_to_exit (WDiff * dview)
+{
+    gboolean res = TRUE;
+    int act;
+
+    if (!dview->merged[DIFF_LEFT] && !dview->merged[DIFF_RIGHT])
+        return res;
+
+    act = query_dialog (_("Quit"), !mc_global.midnight_shutdown ?
+                        _("File(s) was modified. Save with exit?") :
+                        _("Midnight Commander is being shut down.\nSave modified file(s)?"),
+                        D_NORMAL, 2, _("&Yes"), _("&No"));
+
+    /* Esc is No */
+    if (mc_global.midnight_shutdown || (act == -1))
+        act = 1;
+
+    switch (act)
+    {
+    case -1:                   /* Esc */
+        res = FALSE;
+        break;
+    case 0:                    /* Yes */
+        (void) dview_save (dview);
+        res = TRUE;
+        break;
+    case 1:                    /* No */
+        if (mc_util_restore_from_backup_if_possible (dview->file[DIFF_LEFT], "~~~"))
+            res = mc_util_unlink_backup_if_possible (dview->file[DIFF_LEFT], "~~~");
+        if (mc_util_restore_from_backup_if_possible (dview->file[DIFF_RIGHT], "~~~"))
+            res = mc_util_unlink_backup_if_possible (dview->file[DIFF_RIGHT], "~~~");
+        MC_FALLTHROUGH;
+    default:
+        res = TRUE;
+        break;
+    }
+    return res;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static cb_ret_t
+dview_execute_cmd (WDiff * dview, long command)
+{
+    cb_ret_t res = MSG_HANDLED;
+
+    switch (command)
+    {
+    case CK_ShowSymbols:
+        dview->display_symbols ^= 1;
+        dview->new_frame = TRUE;
+        break;
+    case CK_ShowNumbers:
+        dview->display_numbers ^= calc_nwidth ((const GArray * const *) dview->a);
+        dview->new_frame = TRUE;
+        break;
+    case CK_SplitFull:
+        dview->full = !dview->full;
+        dview->new_frame = TRUE;
+        break;
+    case CK_SplitEqual:
+        if (!dview->full)
+        {
+            dview->bias = 0;
+            dview->new_frame = TRUE;
+        }
+        break;
+    case CK_SplitMore:
+        if (!dview->full)
+        {
+            dview_compute_split (dview, 1);
+            dview->new_frame = TRUE;
+        }
+        break;
+
+    case CK_SplitLess:
+        if (!dview->full)
+        {
+            dview_compute_split (dview, -1);
+            dview->new_frame = TRUE;
+        }
+        break;
+    case CK_Tab2:
+        dview->tab_size = 2;
+        break;
+    case CK_Tab3:
+        dview->tab_size = 3;
+        break;
+    case CK_Tab4:
+        dview->tab_size = 4;
+        break;
+    case CK_Tab8:
+        dview->tab_size = 8;
+        break;
+    case CK_Swap:
+        dview->ord ^= 1;
+        break;
+    case CK_Redo:
+        dview_redo (dview);
+        break;
+    case CK_HunkNext:
+        dview->skip_rows = dview->search.last_accessed_num_line =
+            find_next_hunk (dview->a[DIFF_LEFT], dview->skip_rows);
+        break;
+    case CK_HunkPrev:
+        dview->skip_rows = dview->search.last_accessed_num_line =
+            find_prev_hunk (dview->a[DIFF_LEFT], dview->skip_rows);
+        break;
+    case CK_Goto:
+        dview_goto_cmd (dview, DIFF_RIGHT);
+        break;
+    case CK_Edit:
+        dview_edit (dview, dview->ord);
+        break;
+    case CK_Merge:
+        do_merge_hunk (dview, FROM_LEFT_TO_RIGHT);
+        dview_redo (dview);
+        break;
+    case CK_MergeOther:
+        do_merge_hunk (dview, FROM_RIGHT_TO_LEFT);
+        dview_redo (dview);
+        break;
+    case CK_EditOther:
+        dview_edit (dview, dview->ord ^ 1);
+        break;
+    case CK_Search:
+        dview_search_cmd (dview);
+        break;
+    case CK_SearchContinue:
+        dview_continue_search_cmd (dview);
+        break;
+    case CK_Top:
+        dview->skip_rows = dview->search.last_accessed_num_line = 0;
+        break;
+    case CK_Bottom:
+        dview->skip_rows = dview->search.last_accessed_num_line = dview->a[DIFF_LEFT]->len - 1;
+        break;
+    case CK_Up:
+        if (dview->skip_rows > 0)
+        {
+            dview->skip_rows--;
+            dview->search.last_accessed_num_line = dview->skip_rows;
+        }
+        break;
+    case CK_Down:
+        dview->skip_rows++;
+        dview->search.last_accessed_num_line = dview->skip_rows;
+        break;
+    case CK_PageDown:
+        if (dview->height > 2)
+        {
+            dview->skip_rows += dview->height - 2;
+            dview->search.last_accessed_num_line = dview->skip_rows;
+        }
+        break;
+    case CK_PageUp:
+        if (dview->height > 2)
+        {
+            dview->skip_rows -= dview->height - 2;
+            dview->search.last_accessed_num_line = dview->skip_rows;
+        }
+        break;
+    case CK_Left:
+        dview->skip_cols--;
+        break;
+    case CK_Right:
+        dview->skip_cols++;
+        break;
+    case CK_LeftQuick:
+        dview->skip_cols -= 8;
+        break;
+    case CK_RightQuick:
+        dview->skip_cols += 8;
+        break;
+    case CK_Home:
+        dview->skip_cols = 0;
+        break;
+    case CK_Shell:
+        toggle_subshell ();
+        break;
+    case CK_Quit:
+        dview->view_quit = TRUE;
+        break;
+    case CK_Save:
+        dview_do_save (dview);
+        break;
+    case CK_Options:
+        dview_diff_options (dview);
+        break;
+#ifdef HAVE_CHARSET
+    case CK_SelectCodepage:
+        dview_select_encoding (dview);
+        break;
+#endif
+    case CK_Cancel:
+        /* don't close diffviewer due to SIGINT */
+        break;
+    default:
+        res = MSG_NOT_HANDLED;
+    }
+    return res;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static cb_ret_t
+dview_handle_key (WDiff * dview, int key)
+{
+    long command;
+
+#ifdef HAVE_CHARSET
+    key = convert_from_input_c (key);
+#endif
+
+    command = widget_lookup_key (WIDGET (dview), key);
+    if (command == CK_IgnoreKey)
+        return MSG_NOT_HANDLED;
+
+    return dview_execute_cmd (dview, command);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static cb_ret_t
+dview_callback (Widget * w, Widget * sender, widget_msg_t msg, int parm, void *data)
+{
+    WDiff *dview = (WDiff *) w;
+    WDialog *h = DIALOG (w->owner);
+    cb_ret_t i;
+
+    switch (msg)
+    {
+    case MSG_INIT:
+        dview_labels (dview);
+        dview_load_options (dview);
+        dview_update (dview);
+        return MSG_HANDLED;
+
+    case MSG_DRAW:
+        dview->new_frame = TRUE;
+        dview_update (dview);
+        return MSG_HANDLED;
+
+    case MSG_KEY:
+        i = dview_handle_key (dview, parm);
+        if (dview->view_quit)
+            dlg_stop (h);
+        else
+            dview_update (dview);
+        return i;
+
+    case MSG_ACTION:
+        i = dview_execute_cmd (dview, parm);
+        if (dview->view_quit)
+            dlg_stop (h);
+        else
+            dview_update (dview);
+        return i;
+
+    case MSG_RESIZE:
+        widget_default_callback (w, NULL, MSG_RESIZE, 0, data);
+        dview_compute_areas (dview);
+        return MSG_HANDLED;
+
+    case MSG_DESTROY:
+        dview_save_options (dview);
+        dview_fini (dview);
+        return MSG_HANDLED;
+
+    default:
+        return widget_default_callback (w, sender, msg, parm, data);
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+dview_mouse_callback (Widget * w, mouse_msg_t msg, mouse_event_t * event)
+{
+    WDiff *dview = (WDiff *) w;
+
+    (void) event;
+
+    switch (msg)
+    {
+    case MSG_MOUSE_SCROLL_UP:
+    case MSG_MOUSE_SCROLL_DOWN:
+        if (msg == MSG_MOUSE_SCROLL_UP)
+            dview->skip_rows -= 2;
+        else
+            dview->skip_rows += 2;
+
+        dview->search.last_accessed_num_line = dview->skip_rows;
+        dview_update (dview);
+        break;
+
+    default:
+        break;
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static cb_ret_t
+dview_dialog_callback (Widget * w, Widget * sender, widget_msg_t msg, int parm, void *data)
+{
+    WDiff *dview;
+    WDialog *h = DIALOG (w);
+
+    switch (msg)
+    {
+    case MSG_ACTION:
+        /* Handle shortcuts. */
+
+        /* Note: the buttonbar sends messages directly to the the WDiff, not to
+         * here, which is why we can pass NULL in the following call. */
+        return dview_execute_cmd (NULL, parm);
+
+    case MSG_VALIDATE:
+        dview = (WDiff *) widget_find_by_type (CONST_WIDGET (h), dview_callback);
+        /* don't stop the dialog before final decision */
+        widget_set_state (w, WST_ACTIVE, TRUE);
+        if (dview_ok_to_exit (dview))
+            dlg_stop (h);
+        return MSG_HANDLED;
+
+    default:
+        return dlg_default_callback (w, sender, msg, parm, data);
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static char *
+dview_get_title (const WDialog * h, size_t len)
+{
+    const WDiff *dview;
+    const char *modified = " (*) ";
+    const char *notmodified = "     ";
+    size_t len1;
+    GString *title;
+
+    dview = (const WDiff *) widget_find_by_type (CONST_WIDGET (h), dview_callback);
+    len1 = (len - str_term_width1 (_("Diff:")) - strlen (modified) - 3) / 2;
+
+    title = g_string_sized_new (len);
+    g_string_append (title, _("Diff:"));
+    g_string_append (title, dview->merged[DIFF_LEFT] ? modified : notmodified);
+    g_string_append (title, str_term_trim (dview->label[DIFF_LEFT], len1));
+    g_string_append (title, " | ");
+    g_string_append (title, dview->merged[DIFF_RIGHT] ? modified : notmodified);
+    g_string_append (title, str_term_trim (dview->label[DIFF_RIGHT], len1));
+
+    return g_string_free (title, FALSE);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static int
+diff_view (const char *file1, const char *file2, const char *label1, const char *label2)
+{
+    int error;
+    WDiff *dview;
+    Widget *w;
+    WDialog *dview_dlg;
+    Widget *dw;
+    WRect r;
+    WGroup *g;
+
+    /* Create dialog and widgets, put them on the dialog */
+    dview_dlg =
+        dlg_create (FALSE, 0, 0, 1, 1, WPOS_FULLSCREEN, FALSE, NULL, dview_dialog_callback, NULL,
+                    "[Diff Viewer]", NULL);
+    dw = WIDGET (dview_dlg);
+    widget_want_tab (dw, TRUE);
+    r = dw->rect;
+
+    g = GROUP (dview_dlg);
+
+    dview = g_new0 (WDiff, 1);
+    w = WIDGET (dview);
+    r.lines--;
+    widget_init (w, &r, dview_callback, dview_mouse_callback);
+    w->options |= WOP_SELECTABLE;
+    w->keymap = diff_map;
+    group_add_widget_autopos (g, w, WPOS_KEEP_ALL, NULL);
+
+    w = WIDGET (buttonbar_new ());
+    group_add_widget_autopos (g, w, w->pos_flags, NULL);
+
+    dview_dlg->get_title = dview_get_title;
+
+    error = dview_init (dview, "-a", file1, file2, label1, label2, DATA_SRC_MEM);       /* XXX binary diff? */
+
+    if (error == 0)
+        dlg_run (dview_dlg);
+
+    if (error != 0 || widget_get_state (dw, WST_CLOSED))
+        widget_destroy (dw);
+
+    return error == 0 ? 1 : 0;
+}
+
+/*** public functions ****************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+
+#define GET_FILE_AND_STAMP(n) \
+do \
+{ \
+    use_copy##n = 0; \
+    real_file##n = file##n; \
+    if (!vfs_file_is_local (file##n)) \
+    { \
+        real_file##n = mc_getlocalcopy (file##n); \
+        if (real_file##n != NULL) \
+        { \
+            use_copy##n = 1; \
+            if (mc_stat (real_file##n, &st##n) != 0) \
+                use_copy##n = -1; \
+        } \
+    } \
+} \
+while (0)
+
+#define UNGET_FILE(n) \
+do \
+{ \
+    if (use_copy##n) \
+    { \
+        int changed = 0; \
+        if (use_copy##n > 0) \
+        { \
+            time_t mtime; \
+            mtime = st##n.st_mtime; \
+            if (mc_stat (real_file##n, &st##n) == 0) \
+                changed = (mtime != st##n.st_mtime); \
+        } \
+        mc_ungetlocalcopy (file##n, real_file##n, changed); \
+        vfs_path_free (real_file##n, TRUE); \
+    } \
+} \
+while (0)
+
+gboolean
+dview_diff_cmd (const void *f0, const void *f1)
+{
+    int rv = 0;
+    vfs_path_t *file0 = NULL;
+    vfs_path_t *file1 = NULL;
+    gboolean is_dir0 = FALSE;
+    gboolean is_dir1 = FALSE;
+
+    switch (mc_global.mc_run_mode)
+    {
+    case MC_RUN_FULL:
+        {
+            /* run from panels */
+            const WPanel *panel0 = (const WPanel *) f0;
+            const WPanel *panel1 = (const WPanel *) f1;
+
+            file0 =
+                vfs_path_append_new (panel0->cwd_vpath, selection (panel0)->fname->str,
+                                     (char *) NULL);
+            is_dir0 = S_ISDIR (selection (panel0)->st.st_mode);
+            if (is_dir0)
+            {
+                message (D_ERROR, MSG_ERROR, _("\"%s\" is a directory"),
+                         path_trunc (selection (panel0)->fname->str, 30));
+                goto ret;
+            }
+
+            file1 =
+                vfs_path_append_new (panel1->cwd_vpath, selection (panel1)->fname->str,
+                                     (char *) NULL);
+            is_dir1 = S_ISDIR (selection (panel1)->st.st_mode);
+            if (is_dir1)
+            {
+                message (D_ERROR, MSG_ERROR, _("\"%s\" is a directory"),
+                         path_trunc (selection (panel1)->fname->str, 30));
+                goto ret;
+            }
+            break;
+        }
+
+    case MC_RUN_DIFFVIEWER:
+        {
+            /* run from command line */
+            const char *p0 = (const char *) f0;
+            const char *p1 = (const char *) f1;
+            struct stat st;
+
+            file0 = vfs_path_from_str (p0);
+            if (mc_stat (file0, &st) == 0)
+            {
+                is_dir0 = S_ISDIR (st.st_mode);
+                if (is_dir0)
+                {
+                    message (D_ERROR, MSG_ERROR, _("\"%s\" is a directory"), path_trunc (p0, 30));
+                    goto ret;
+                }
+            }
+            else
+            {
+                message (D_ERROR, MSG_ERROR, _("Cannot stat \"%s\"\n%s"),
+                         path_trunc (p0, 30), unix_error_string (errno));
+                goto ret;
+            }
+
+            file1 = vfs_path_from_str (p1);
+            if (mc_stat (file1, &st) == 0)
+            {
+                is_dir1 = S_ISDIR (st.st_mode);
+                if (is_dir1)
+                {
+                    message (D_ERROR, MSG_ERROR, _("\"%s\" is a directory"), path_trunc (p1, 30));
+                    goto ret;
+                }
+            }
+            else
+            {
+                message (D_ERROR, MSG_ERROR, _("Cannot stat \"%s\"\n%s"),
+                         path_trunc (p1, 30), unix_error_string (errno));
+                goto ret;
+            }
+            break;
+        }
+
+    default:
+        /* this should not happaned */
+        message (D_ERROR, MSG_ERROR, _("Diff viewer: invalid mode"));
+        return FALSE;
+    }
+
+    if (rv == 0)
+    {
+        rv = -1;
+        if (file0 != NULL && file1 != NULL)
+        {
+            int use_copy0;
+            int use_copy1;
+            struct stat st0;
+            struct stat st1;
+            vfs_path_t *real_file0;
+            vfs_path_t *real_file1;
+
+            GET_FILE_AND_STAMP (0);
+            GET_FILE_AND_STAMP (1);
+
+            if (real_file0 != NULL && real_file1 != NULL)
+                rv = diff_view (vfs_path_as_str (real_file0), vfs_path_as_str (real_file1),
+                                vfs_path_as_str (file0), vfs_path_as_str (file1));
+
+            UNGET_FILE (1);
+            UNGET_FILE (0);
+        }
+    }
+
+    if (rv == 0)
+        message (D_ERROR, MSG_ERROR, _("Two files are needed to compare"));
+
+  ret:
+    vfs_path_free (file1, TRUE);
+    vfs_path_free (file0, TRUE);
+
+    return (rv != 0);
+}
+
+#undef GET_FILE_AND_STAMP
+#undef UNGET_FILE
+
+/* --------------------------------------------------------------------------------------------- */