1 files changed, 539 insertions, 0 deletions
diff --git a/src/editor/format.c b/src/editor/format.c
new file mode 100644
index 0000000..1da94ec
--- /dev/null
+++ b/src/editor/format.c
@@ -0,0 +1,539 @@
+/*
+   Dynamic paragraph formatting.
+
+   Copyright (C) 2011-2022
+   Free Software Foundation, Inc.
+
+   Copyright (C) 1996 Paul Sheer
+
+   Writen by:
+   Paul Sheer, 1996
+   Andrew Borodin <aborodin@vmail.ru>, 2013, 2014
+
+   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/>.
+ */
+
+/** \file
+ *  \brief Source: Dynamic paragraph formatting
+ *  \author Paul Sheer
+ *  \date 1996
+ *  \author Andrew Borodin
+ *  \date 2013, 2014
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include <stdlib.h>
+
+#include "lib/global.h"
+
+#include "src/setup.h"          /* option_tab_spacing */
+
+#include "edit-impl.h"
+#include "editwidget.h"
+
+/*** global variables ****************************************************************************/
+
+char *option_stop_format_chars = NULL;
+
+/*** file scope macro definitions ****************************************************************/
+
+#define tab_width option_tab_spacing
+
+#define FONT_MEAN_WIDTH 1
+
+/*** file scope type declarations ****************************************************************/
+
+/*** file scope variables ************************************************************************/
+
+/*** file scope functions ************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+
+static off_t
+line_start (const edit_buffer_t * buf, long line)
+{
+    off_t p;
+    long l;
+
+    l = buf->curs_line;
+    p = buf->curs1;
+
+    if (line < l)
+        p = edit_buffer_get_backward_offset (buf, p, l - line);
+    else if (line > l)
+        p = edit_buffer_get_forward_offset (buf, p, line - l, 0);
+
+    p = edit_buffer_get_bol (buf, p);
+    while (strchr ("\t ", edit_buffer_get_byte (buf, p)) != NULL)
+        p++;
+    return p;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static gboolean
+bad_line_start (const edit_buffer_t * buf, off_t p)
+{
+    int c;
+
+    c = edit_buffer_get_byte (buf, p);
+    if (c == '.')
+    {
+        /* `...' is acceptable */
+        return !(edit_buffer_get_byte (buf, p + 1) == '.'
+                 && edit_buffer_get_byte (buf, p + 2) == '.');
+    }
+    if (c == '-')
+    {
+        /* `---' is acceptable */
+        return !(edit_buffer_get_byte (buf, p + 1) == '-'
+                 && edit_buffer_get_byte (buf, p + 2) == '-');
+    }
+
+    return (option_stop_format_chars != NULL && strchr (option_stop_format_chars, c) != NULL);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Find the start of the current paragraph for the purpose of formatting.
+ * Return position in the file.
+ */
+
+static off_t
+begin_paragraph (WEdit * edit, gboolean force, long *lines)
+{
+    long i;
+
+    for (i = edit->buffer.curs_line - 1; i >= 0; i--)
+        if (edit_line_is_blank (edit, i) ||
+            (force && bad_line_start (&edit->buffer, line_start (&edit->buffer, i))))
+        {
+            i++;
+            break;
+        }
+
+    *lines = edit->buffer.curs_line - i;
+
+    return edit_buffer_get_backward_offset (&edit->buffer,
+                                            edit_buffer_get_current_bol (&edit->buffer), *lines);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Find the end of the current paragraph for the purpose of formatting.
+ * Return position in the file.
+ */
+
+static off_t
+end_paragraph (WEdit * edit, gboolean force)
+{
+    long i;
+
+    for (i = edit->buffer.curs_line + 1; i <= edit->buffer.lines; i++)
+        if (edit_line_is_blank (edit, i) ||
+            (force && bad_line_start (&edit->buffer, line_start (&edit->buffer, i))))
+        {
+            i--;
+            break;
+        }
+
+    return edit_buffer_get_eol (&edit->buffer,
+                                edit_buffer_get_forward_offset (&edit->buffer,
+                                                                edit_buffer_get_current_bol
+                                                                (&edit->buffer),
+                                                                i - edit->buffer.curs_line, 0));
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static GString *
+get_paragraph (const edit_buffer_t * buf, off_t p, off_t q, gboolean indent)
+{
+    GString *t;
+
+    t = g_string_sized_new (128);
+
+    for (; p < q; p++)
+    {
+        if (indent && edit_buffer_get_byte (buf, p - 1) == '\n')
+            while (strchr ("\t ", edit_buffer_get_byte (buf, p)) != NULL)
+                p++;
+
+        g_string_append_c (t, edit_buffer_get_byte (buf, p));
+    }
+
+    g_string_append_c (t, '\n');
+
+    return t;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static inline void
+strip_newlines (unsigned char *t, off_t size)
+{
+    unsigned char *p;
+
+    for (p = t; size-- != 0; p++)
+        if (*p == '\n')
+            *p = ' ';
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+   This function calculates the number of chars in a line specified to length l in pixels
+ */
+
+static inline off_t
+next_tab_pos (off_t x)
+{
+    x += tab_width - x % tab_width;
+    return x;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static inline off_t
+line_pixel_length (unsigned char *t, off_t b, off_t l, gboolean utf8)
+{
+    off_t xn, x;                /* position conters */
+    off_t char_length;          /* character length in bytes */
+
+#ifndef HAVE_CHARSET
+    (void) utf8;
+#endif
+
+    for (xn = 0, x = 0; xn <= l; x = xn, b += char_length)
+    {
+        char *tb;
+
+        tb = (char *) t + b;
+        char_length = 1;
+
+        switch (tb[0])
+        {
+        case '\n':
+            return b;
+        case '\t':
+            xn = next_tab_pos (x);
+            break;
+        default:
+#ifdef HAVE_CHARSET
+            if (utf8)
+            {
+                gunichar ch;
+
+                ch = g_utf8_get_char_validated (tb, -1);
+                if (ch != (gunichar) (-2) && ch != (gunichar) (-1))
+                {
+                    char *next_ch;
+
+                    /* Calculate UTF-8 char length */
+                    next_ch = g_utf8_next_char (tb);
+                    char_length = next_ch - tb;
+
+                    if (g_unichar_iswide (ch))
+                        x++;
+                }
+            }
+#endif
+
+            xn = x + 1;
+            break;
+        }
+    }
+
+    return b;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static off_t
+next_word_start (unsigned char *t, off_t q, off_t size)
+{
+    off_t i;
+    gboolean saw_ws = FALSE;
+
+    for (i = q; i < size; i++)
+    {
+        switch (t[i])
+        {
+        case '\n':
+            return -1;
+        case '\t':
+        case ' ':
+            saw_ws = TRUE;
+            break;
+        default:
+            if (saw_ws)
+                return i;
+            break;
+        }
+    }
+    return (-1);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/** find the start of a word */
+
+static inline int
+word_start (unsigned char *t, off_t q, off_t size)
+{
+    off_t i;
+
+    if (whitespace (t[q]))
+        return next_word_start (t, q, size);
+
+    for (i = q;; i--)
+    {
+        unsigned char c;
+
+        if (i == 0)
+            return (-1);
+        c = t[i - 1];
+        if (c == '\n')
+            return (-1);
+        if (whitespace (c))
+            return i;
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/** replaces ' ' with '\n' to properly format a paragraph */
+
+static inline void
+format_this (unsigned char *t, off_t size, long indent, gboolean utf8)
+{
+    off_t q = 0, ww;
+
+    strip_newlines (t, size);
+    ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
+    if (ww < FONT_MEAN_WIDTH * 2)
+        ww = FONT_MEAN_WIDTH * 2;
+
+    while (TRUE)
+    {
+        off_t p;
+
+        q = line_pixel_length (t, q, ww, utf8);
+        if (q > size)
+            break;
+        if (t[q] == '\n')
+            break;
+        p = word_start (t, q, size);
+        if (p == -1)
+            q = next_word_start (t, q, size);   /* Return the end of the word if the beginning
+                                                   of the word is at the beginning of a line
+                                                   (i.e. a very long word) */
+        else
+            q = p;
+        if (q == -1)            /* end of paragraph */
+            break;
+        if (q != 0)
+            t[q - 1] = '\n';
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static inline void
+replace_at (WEdit * edit, off_t q, int c)
+{
+    edit_cursor_move (edit, q - edit->buffer.curs1);
+    edit_delete (edit, TRUE);
+    edit_insert_ahead (edit, c);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static long
+edit_indent_width (const WEdit * edit, off_t p)
+{
+    off_t q = p;
+
+    /* move to the end of the leading whitespace of the line */
+    while (strchr ("\t ", edit_buffer_get_byte (&edit->buffer, q)) != NULL
+           && q < edit->buffer.size - 1)
+        q++;
+    /* count the number of columns of indentation */
+    return (long) edit_move_forward3 (edit, p, 0, q);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static void
+edit_insert_indent (WEdit * edit, long indent)
+{
+    if (!option_fill_tabs_with_spaces)
+        while (indent >= TAB_SIZE)
+        {
+            edit_insert (edit, '\t');
+            indent -= TAB_SIZE;
+        }
+
+    while (indent-- > 0)
+        edit_insert (edit, ' ');
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/** replaces a block of text */
+
+static inline void
+put_paragraph (WEdit * edit, unsigned char *t, off_t p, long indent, off_t size)
+{
+    off_t cursor;
+    off_t i;
+    int c = '\0';
+
+    cursor = edit->buffer.curs1;
+    if (indent != 0)
+        while (strchr ("\t ", edit_buffer_get_byte (&edit->buffer, p)) != NULL)
+            p++;
+    for (i = 0; i < size; i++, p++)
+    {
+        if (i != 0 && indent != 0)
+        {
+            if (t[i - 1] == '\n' && c == '\n')
+            {
+                while (strchr ("\t ", edit_buffer_get_byte (&edit->buffer, p)) != NULL)
+                    p++;
+            }
+            else if (t[i - 1] == '\n')
+            {
+                off_t curs;
+
+                edit_cursor_move (edit, p - edit->buffer.curs1);
+                curs = edit->buffer.curs1;
+                edit_insert_indent (edit, indent);
+                if (cursor >= curs)
+                    cursor += edit->buffer.curs1 - p;
+                p = edit->buffer.curs1;
+            }
+            else if (c == '\n')
+            {
+                edit_cursor_move (edit, p - edit->buffer.curs1);
+                while (strchr ("\t ", edit_buffer_get_byte (&edit->buffer, p)) != NULL)
+                {
+                    edit_delete (edit, TRUE);
+                    if (cursor > edit->buffer.curs1)
+                        cursor--;
+                }
+                p = edit->buffer.curs1;
+            }
+        }
+
+        c = edit_buffer_get_byte (&edit->buffer, p);
+        if (c != t[i])
+            replace_at (edit, p, t[i]);
+    }
+    edit_cursor_move (edit, cursor - edit->buffer.curs1);       /* restore cursor position */
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+static inline long
+test_indent (const WEdit * edit, off_t p, off_t q)
+{
+    long indent;
+
+    indent = edit_indent_width (edit, p++);
+    if (indent == 0)
+        return 0;
+
+    for (; p < q; p++)
+        if (edit_buffer_get_byte (&edit->buffer, p - 1) == '\n'
+            && indent != edit_indent_width (edit, p))
+            return 0;
+    return indent;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/*** public functions ****************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+
+void
+format_paragraph (WEdit * edit, gboolean force)
+{
+    off_t p, q;
+    long lines;
+    off_t size;
+    GString *t;
+    long indent;
+    unsigned char *t2;
+    gboolean utf8 = FALSE;
+
+    if (option_word_wrap_line_length < 2)
+        return;
+    if (edit_line_is_blank (edit, edit->buffer.curs_line))
+        return;
+
+    p = begin_paragraph (edit, force, &lines);
+    q = end_paragraph (edit, force);
+    indent = test_indent (edit, p, q);
+
+    t = get_paragraph (&edit->buffer, p, q, indent != 0);
+    size = t->len - 1;
+
+    if (!force)
+    {
+        off_t i;
+        char *stop_format_chars;
+
+        if (option_stop_format_chars != NULL
+            && strchr (option_stop_format_chars, t->str[0]) != NULL)
+        {
+            g_string_free (t, TRUE);
+            return;
+        }
+
+        if (option_stop_format_chars == NULL || *option_stop_format_chars == '\0')
+            stop_format_chars = g_strdup ("\t");
+        else
+            stop_format_chars = g_strconcat (option_stop_format_chars, "\t", (char *) NULL);
+
+        for (i = 0; i < size - 1; i++)
+            if (t->str[i] == '\n' && strchr (stop_format_chars, t->str[i + 1]) != NULL)
+            {
+                g_free (stop_format_chars);
+                g_string_free (t, TRUE);
+                return;
+            }
+
+        g_free (stop_format_chars);
+    }
+
+    t2 = (unsigned char *) g_string_free (t, FALSE);
+#ifdef HAVE_CHARSET
+    utf8 = edit->utf8;
+#endif
+    format_this (t2, q - p, indent, utf8);
+    put_paragraph (edit, t2, p, indent, size);
+    g_free ((char *) t2);
+
+    /* Scroll left as much as possible to show the formatted paragraph */
+    edit_scroll_left (edit, -edit->start_col);
+}
+
+/* --------------------------------------------------------------------------------------------- */