summaryrefslogtreecommitdiffstats
path: root/src/editor/editbuffer.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--src/editor/editbuffer.c900
1 files changed, 900 insertions, 0 deletions
diff --git a/src/editor/editbuffer.c b/src/editor/editbuffer.c
new file mode 100644
index 0000000..24bc7ee
--- /dev/null
+++ b/src/editor/editbuffer.c
@@ -0,0 +1,900 @@
+/*
+ Editor text keep buffer.
+
+ Copyright (C) 2013-2023
+ Free Software Foundation, Inc.
+
+ Written by:
+ Andrew Borodin <aborodin@vmail.ru> 2013
+
+ 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: editor text keep buffer.
+ * \author Andrew Borodin
+ * \date 2013
+ */
+
+#include <config.h>
+
+#include <ctype.h> /* isdigit() */
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "lib/global.h"
+
+#include "lib/vfs/vfs.h"
+
+#include "edit-impl.h"
+#include "editbuffer.h"
+
+/* --------------------------------------------------------------------------------------------- */
+/*-
+ *
+ * here's a quick sketch of the layout: (don't run this through indent.)
+ *
+ * |
+ * \0\0\0\0\0m e _ f i l e . \nf i n . \n|T h i s _ i s _ s o\0\0\0\0\0\0\0\0\0
+ * ______________________________________|______________________________________
+ * |
+ * ... | b2[2] | b2[1] | b2[0] | b1[0] | b1[1] | b1[2] | ...
+ * |-> |-> |-> |-> |-> |-> |
+ * |
+ * _<------------------------->|<----------------->_
+ * curs2 | curs1
+ * ^ | ^
+ * | ^|^ |
+ * cursor ||| cursor
+ * |||
+ * file end|||file beginning
+ * |
+ * |
+ *
+ * _
+ * This_is_some_file
+ * fin.
+ *
+ *
+ * This is called a "gap buffer".
+ * See also:
+ * http://en.wikipedia.org/wiki/Gap_buffer
+ * http://stackoverflow.com/questions/4199694/data-structure-for-text-editor
+ */
+
+/*** global variables ****************************************************************************/
+
+/*** file scope macro definitions ****************************************************************/
+
+/*
+ * The editor keeps data in two arrays of buffers.
+ * All buffers have the same size, which must be a power of 2.
+ */
+
+/* Configurable: log2 of the buffer size in bytes */
+#ifndef S_EDIT_BUF_SIZE
+#define S_EDIT_BUF_SIZE 16
+#endif
+
+/* Size of the buffer */
+#define EDIT_BUF_SIZE (((off_t) 1) << S_EDIT_BUF_SIZE)
+
+/* Buffer mask (used to find cursor position relative to the buffer) */
+#define M_EDIT_BUF_SIZE (EDIT_BUF_SIZE - 1)
+
+/*** file scope type declarations ****************************************************************/
+
+/*** forward declarations (file scope functions) *************************************************/
+
+/*** file scope variables ************************************************************************/
+
+/* --------------------------------------------------------------------------------------------- */
+/*** file scope functions ************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Get pointer to byte at specified index
+ *
+ * @param buf pointer to editor buffer
+ * @param byte_index byte index
+ *
+ * @return NULL if byte_index is negative or larger than file size; pointer to byte otherwise.
+ */
+static char *
+edit_buffer_get_byte_ptr (const edit_buffer_t * buf, off_t byte_index)
+{
+ void *b;
+
+ if (byte_index >= (buf->curs1 + buf->curs2) || byte_index < 0)
+ return NULL;
+
+ if (byte_index >= buf->curs1)
+ {
+ off_t p;
+
+ p = buf->curs1 + buf->curs2 - byte_index - 1;
+ b = g_ptr_array_index (buf->b2, p >> S_EDIT_BUF_SIZE);
+ return (char *) b + EDIT_BUF_SIZE - 1 - (p & M_EDIT_BUF_SIZE);
+ }
+
+ b = g_ptr_array_index (buf->b1, byte_index >> S_EDIT_BUF_SIZE);
+ return (char *) b + (byte_index & M_EDIT_BUF_SIZE);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/*** public functions ****************************************************************************/
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Initialize editor buffers.
+ *
+ * @param buf pointer to editor buffer
+ */
+
+void
+edit_buffer_init (edit_buffer_t * buf, off_t size)
+{
+ buf->b1 = g_ptr_array_new_full (32, g_free);
+ buf->b2 = g_ptr_array_new_full (32, g_free);
+
+ buf->curs1 = 0;
+ buf->curs2 = 0;
+
+ buf->size = size;
+ buf->lines = 0;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Clean editor buffers.
+ *
+ * @param buf pointer to editor buffer
+ */
+
+void
+edit_buffer_clean (edit_buffer_t * buf)
+{
+ if (buf->b1 != NULL)
+ g_ptr_array_free (buf->b1, TRUE);
+
+ if (buf->b2 != NULL)
+ g_ptr_array_free (buf->b2, TRUE);
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Get byte at specified index
+ *
+ * @param buf pointer to editor buffer
+ * @param byte_index byte index
+ *
+ * @return '\n' if byte_index is negative or larger than file size; byte at byte_index otherwise.
+ */
+
+int
+edit_buffer_get_byte (const edit_buffer_t * buf, off_t byte_index)
+{
+ char *p;
+
+ p = edit_buffer_get_byte_ptr (buf, byte_index);
+
+ return (p != NULL) ? *(unsigned char *) p : '\n';
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
+#ifdef HAVE_CHARSET
+/**
+ * Get utf-8 symbol at specified index
+ *
+ * @param buf pointer to editor buffer
+ * @param byte_index byte index
+ * @param char_length length of returned symbol
+ *
+ * @return '\n' if byte_index is negative or larger than file size;
+ * 0 if utf-8 symbol at specified index is invalid;
+ * utf-8 symbol otherwise
+ */
+
+int
+edit_buffer_get_utf (const edit_buffer_t * buf, off_t byte_index, int *char_length)
+{
+ gchar *str = NULL;
+ gunichar res;
+ gunichar ch;
+ gchar *next_ch = NULL;
+
+ if (byte_index >= (buf->curs1 + buf->curs2) || byte_index < 0)
+ {
+ *char_length = 0;
+ return '\n';
+ }
+
+ str = edit_buffer_get_byte_ptr (buf, byte_index);
+ if (str == NULL)
+ {
+ *char_length = 0;
+ return 0;
+ }
+
+ res = g_utf8_get_char_validated (str, -1);
+ if (res == (gunichar) (-2) || res == (gunichar) (-1))
+ {
+ /* Retry with explicit bytes to make sure it's not a buffer boundary */
+ size_t i;
+ gchar utf8_buf[UTF8_CHAR_LEN + 1];
+
+ for (i = 0; i < UTF8_CHAR_LEN; i++)
+ utf8_buf[i] = edit_buffer_get_byte (buf, byte_index + i);
+ utf8_buf[i] = '\0';
+ res = g_utf8_get_char_validated (utf8_buf, -1);
+ }
+
+ if (res == (gunichar) (-2) || res == (gunichar) (-1))
+ {
+ ch = *str;
+ *char_length = 0;
+ }
+ else
+ {
+ ch = res;
+ /* Calculate UTF-8 char length */
+ next_ch = g_utf8_next_char (str);
+ *char_length = next_ch - str;
+ }
+
+ return (int) ch;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Get utf-8 symbol before specified index
+ *
+ * @param buf pointer to editor buffer
+ * @param byte_index byte index
+ * @param char_length length of returned symbol
+ *
+ * @return 0 if byte_index is negative or larger than file size;
+ * 1-byte value before specified index if utf-8 symbol before specified index is invalid;
+ * utf-8 symbol otherwise
+ */
+
+int
+edit_buffer_get_prev_utf (const edit_buffer_t * buf, off_t byte_index, int *char_length)
+{
+ size_t i;
+ gchar utf8_buf[3 * UTF8_CHAR_LEN + 1];
+ gchar *str;
+ gchar *cursor_buf_ptr;
+ gunichar res;
+
+ if (byte_index > (buf->curs1 + buf->curs2) || byte_index <= 0)
+ {
+ *char_length = 0;
+ return 0;
+ }
+
+ for (i = 0; i < (3 * UTF8_CHAR_LEN); i++)
+ utf8_buf[i] = edit_buffer_get_byte (buf, byte_index + i - (2 * UTF8_CHAR_LEN));
+ utf8_buf[i] = '\0';
+
+ cursor_buf_ptr = utf8_buf + (2 * UTF8_CHAR_LEN);
+ str = g_utf8_find_prev_char (utf8_buf, cursor_buf_ptr);
+
+ if (str == NULL || g_utf8_next_char (str) != cursor_buf_ptr)
+ {
+ *char_length = 1;
+ return *(cursor_buf_ptr - 1);
+ }
+
+ res = g_utf8_get_char_validated (str, -1);
+ if (res == (gunichar) (-2) || res == (gunichar) (-1))
+ {
+ *char_length = 1;
+ return *(cursor_buf_ptr - 1);
+ }
+
+ *char_length = cursor_buf_ptr - str;
+ return (int) res;
+}
+#endif /* HAVE_CHARSET */
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Count lines in editor buffer.
+ *
+ * @param buf editor buffer
+ * @param first start byte offset
+ * @param last finish byte offset
+ *
+ * @return line numbers between "first" and "last" bytes
+ */
+
+long
+edit_buffer_count_lines (const edit_buffer_t * buf, off_t first, off_t last)
+{
+ long lines = 0;
+
+ first = MAX (first, 0);
+ last = MIN (last, buf->size);
+
+ while (first < last)
+ if (edit_buffer_get_byte (buf, first++) == '\n')
+ lines++;
+
+ return lines;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Get "begin-of-line" offset of line contained specified byte offset
+ *
+ * @param buf editor buffer
+ * @param current byte offset
+ *
+ * @return index of first char of line
+ */
+
+off_t
+edit_buffer_get_bol (const edit_buffer_t * buf, off_t current)
+{
+ if (current <= 0)
+ return 0;
+
+ for (; edit_buffer_get_byte (buf, current - 1) != '\n'; current--)
+ ;
+
+ return current;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Get "end-of-line" offset of line contained specified byte offset
+ *
+ * @param buf editor buffer
+ * @param current byte offset
+ *
+ * @return index of last char of line + 1
+ */
+
+off_t
+edit_buffer_get_eol (const edit_buffer_t * buf, off_t current)
+{
+ if (current >= buf->size)
+ return buf->size;
+
+ for (; edit_buffer_get_byte (buf, current) != '\n'; current++)
+ ;
+
+ return current;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Get word from specified offset.
+ *
+ * @param buf editor buffer
+ * @param current start_pos offset
+ * @param start actual start word ofset
+ * @param cut
+ *
+ * @return word as newly allocated object
+ */
+
+GString *
+edit_buffer_get_word_from_pos (const edit_buffer_t * buf, off_t start_pos, off_t * start,
+ gsize * cut)
+{
+ off_t word_start;
+ gsize cut_len = 0;
+ GString *match_expr;
+ int c1, c2;
+
+ for (word_start = start_pos; word_start != 0; word_start--, cut_len++)
+ {
+ c1 = edit_buffer_get_byte (buf, word_start);
+ c2 = edit_buffer_get_byte (buf, word_start - 1);
+
+ if (is_break_char (c1) != is_break_char (c2) || c1 == '\n' || c2 == '\n')
+ break;
+ }
+
+ match_expr = g_string_sized_new (16);
+
+ do
+ {
+ c1 = edit_buffer_get_byte (buf, word_start + match_expr->len);
+ c2 = edit_buffer_get_byte (buf, word_start + match_expr->len + 1);
+ g_string_append_c (match_expr, c1);
+ }
+ while (!(is_break_char (c1) != is_break_char (c2) || c1 == '\n' || c2 == '\n'));
+
+ *start = word_start;
+ *cut = cut_len;
+
+ return match_expr;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Find first character of current word
+ *
+ * @param buf editor buffer
+ * @param word_start position of first character of current word
+ * @param word_len length of current word
+ *
+ * @return TRUE if first character of word is found and this character is not 1) a digit and
+ * 2) a begin of file, FALSE otherwise
+ */
+
+gboolean
+edit_buffer_find_word_start (const edit_buffer_t * buf, off_t * word_start, gsize * word_len)
+{
+ int c;
+ off_t i;
+
+ /* return if at begin of file */
+ if (buf->curs1 <= 0)
+ return FALSE;
+
+ c = edit_buffer_get_previous_byte (buf);
+ /* return if not at end or in word */
+ if (is_break_char (c))
+ return FALSE;
+
+ /* search start of word */
+ for (i = 1;; i++)
+ {
+ int last;
+
+ last = c;
+ c = edit_buffer_get_byte (buf, buf->curs1 - i - 1);
+
+ if (is_break_char (c))
+ {
+ /* return if word starts with digit */
+ if (isdigit (last))
+ return FALSE;
+
+ break;
+ }
+ }
+
+ /* success */
+ *word_start = buf->curs1 - i; /* start found */
+ *word_len = (gsize) i;
+
+ return TRUE;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Basic low level single character buffer alterations and movements at the cursor: insert character
+ * at the cursor position and move right.
+ *
+ * @param buf pointer to editor buffer
+ * @param c character to insert
+ */
+
+void
+edit_buffer_insert (edit_buffer_t * buf, int c)
+{
+ void *b;
+ off_t i;
+
+ i = buf->curs1 & M_EDIT_BUF_SIZE;
+
+ /* add a new buffer if we've reached the end of the last one */
+ if (i == 0)
+ g_ptr_array_add (buf->b1, g_malloc0 (EDIT_BUF_SIZE));
+
+ /* perform the insertion */
+ b = g_ptr_array_index (buf->b1, buf->curs1 >> S_EDIT_BUF_SIZE);
+ *((unsigned char *) b + i) = (unsigned char) c;
+
+ /* update cursor position */
+ buf->curs1++;
+
+ /* update file length */
+ buf->size++;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Basic low level single character buffer alterations and movements at the cursor: insert character
+ * at the cursor position and move left.
+ *
+ * @param buf pointer to editor buffer
+ * @param c character to insert
+ */
+
+void
+edit_buffer_insert_ahead (edit_buffer_t * buf, int c)
+{
+ void *b;
+ off_t i;
+
+ i = buf->curs2 & M_EDIT_BUF_SIZE;
+
+ /* add a new buffer if we've reached the end of the last one */
+ if (i == 0)
+ g_ptr_array_add (buf->b2, g_malloc0 (EDIT_BUF_SIZE));
+
+ /* perform the insertion */
+ b = g_ptr_array_index (buf->b2, buf->curs2 >> S_EDIT_BUF_SIZE);
+ *((unsigned char *) b + EDIT_BUF_SIZE - 1 - i) = (unsigned char) c;
+
+ /* update cursor position */
+ buf->curs2++;
+
+ /* update file length */
+ buf->size++;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Basic low level single character buffer alterations and movements at the cursor: delete character
+ * at the cursor position.
+ *
+ * @param buf pointer to editor buffer
+ * @param c character to insert
+ */
+
+int
+edit_buffer_delete (edit_buffer_t * buf)
+{
+ void *b;
+ unsigned char c;
+ off_t prev;
+ off_t i;
+
+ prev = buf->curs2 - 1;
+
+ b = g_ptr_array_index (buf->b2, prev >> S_EDIT_BUF_SIZE);
+ i = prev & M_EDIT_BUF_SIZE;
+ c = *((unsigned char *) b + EDIT_BUF_SIZE - 1 - i);
+
+ if (i == 0)
+ {
+ guint j;
+
+ j = buf->b2->len - 1;
+ b = g_ptr_array_index (buf->b2, j);
+ g_ptr_array_remove_index (buf->b2, j);
+ }
+
+ buf->curs2 = prev;
+
+ /* update file length */
+ buf->size--;
+
+ return c;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Basic low level single character buffer alterations and movements at the cursor: delete character
+ * before the cursor position and move left.
+ *
+ * @param buf pointer to editor buffer
+ * @param c character to insert
+ */
+
+int
+edit_buffer_backspace (edit_buffer_t * buf)
+{
+ void *b;
+ unsigned char c;
+ off_t prev;
+ off_t i;
+
+ prev = buf->curs1 - 1;
+
+ b = g_ptr_array_index (buf->b1, prev >> S_EDIT_BUF_SIZE);
+ i = prev & M_EDIT_BUF_SIZE;
+ c = *((unsigned char *) b + i);
+
+ if (i == 0)
+ {
+ guint j;
+
+ j = buf->b1->len - 1;
+ b = g_ptr_array_index (buf->b1, j);
+ g_ptr_array_remove_index (buf->b1, j);
+ }
+
+ buf->curs1 = prev;
+
+ /* update file length */
+ buf->size--;
+
+ return c;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Calculate forward offset with specified number of lines.
+ *
+ * @param buf editor buffer
+ * @param current current offset
+ * @param lines number of lines to move forward
+ * @param upto offset to count lines between current and upto.
+ *
+ * @return If lines is zero returns the count of lines from current to upto.
+ * If upto is zero returns offset of lines forward current.
+ * Else returns forward offset with specified number of lines
+ */
+
+off_t
+edit_buffer_get_forward_offset (const edit_buffer_t * buf, off_t current, long lines, off_t upto)
+{
+ if (upto != 0)
+ return (off_t) edit_buffer_count_lines (buf, current, upto);
+
+ lines = MAX (lines, 0);
+
+ while (lines-- != 0)
+ {
+ long next;
+
+ next = edit_buffer_get_eol (buf, current) + 1;
+ if (next > buf->size)
+ break;
+ current = next;
+ }
+
+ return current;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Calculate backward offset with specified number of lines.
+ *
+ * @param buf editor buffer
+ * @param current current offset
+ * @param lines number of lines to move backward
+ *
+ * @return backward offset with specified number of lines.
+ */
+
+off_t
+edit_buffer_get_backward_offset (const edit_buffer_t * buf, off_t current, long lines)
+{
+ lines = MAX (lines, 0);
+ current = edit_buffer_get_bol (buf, current);
+
+ while (lines-- != 0 && current != 0)
+ current = edit_buffer_get_bol (buf, current - 1);
+
+ return current;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Load file into editor buffer
+ *
+ * @param buf pointer to editor buffer
+ * @param fd file descriptor
+ * @param size file size
+ *
+ * @return number of read bytes
+ */
+
+off_t
+edit_buffer_read_file (edit_buffer_t * buf, int fd, off_t size,
+ edit_buffer_read_file_status_msg_t * sm, gboolean * aborted)
+{
+ off_t ret = 0;
+ off_t i, j;
+ off_t data_size;
+ void *b;
+ status_msg_t *s = STATUS_MSG (sm);
+ unsigned short update_cnt = 0;
+
+ *aborted = FALSE;
+
+ buf->lines = 0;
+ buf->curs2 = size;
+ i = buf->curs2 >> S_EDIT_BUF_SIZE;
+
+ /* fill last part of b2 */
+ data_size = buf->curs2 & M_EDIT_BUF_SIZE;
+ if (data_size != 0)
+ {
+ b = g_malloc0 (EDIT_BUF_SIZE);
+ g_ptr_array_add (buf->b2, b);
+ b = (char *) b + EDIT_BUF_SIZE - data_size;
+ ret = mc_read (fd, b, data_size);
+
+ /* count lines */
+ for (j = 0; j < ret; j++)
+ if (*((char *) b + j) == '\n')
+ buf->lines++;
+
+ if (ret < 0 || ret != data_size)
+ return ret;
+ }
+
+ /* fulfill other parts of b2 from end to begin */
+ data_size = EDIT_BUF_SIZE;
+ for (--i; i >= 0; i--)
+ {
+ off_t sz;
+
+ b = g_malloc0 (data_size);
+ g_ptr_array_add (buf->b2, b);
+ sz = mc_read (fd, b, data_size);
+ if (sz >= 0)
+ ret += sz;
+
+ /* count lines */
+ for (j = 0; j < sz; j++)
+ if (*((char *) b + j) == '\n')
+ buf->lines++;
+
+ if (s != NULL && s->update != NULL)
+ {
+ update_cnt = (update_cnt + 1) & 0xf;
+ if (update_cnt == 0)
+ {
+ /* FIXME: overcare */
+ if (sm->buf == NULL)
+ sm->buf = buf;
+
+ sm->loaded = ret;
+ if (s->update (s) == B_CANCEL)
+ {
+ *aborted = TRUE;
+ return (-1);
+ }
+ }
+ }
+
+ if (sz != data_size)
+ break;
+ }
+
+ /* reverse buffer */
+ for (i = 0; i < (off_t) buf->b2->len / 2; i++)
+ {
+ void **b1, **b2;
+
+ b1 = &g_ptr_array_index (buf->b2, i);
+ b2 = &g_ptr_array_index (buf->b2, buf->b2->len - 1 - i);
+
+ b = *b1;
+ *b1 = *b2;
+ *b2 = b;
+
+ if (s != NULL && s->update != NULL)
+ {
+ update_cnt = (update_cnt + 1) & 0xf;
+ if (update_cnt == 0)
+ {
+ sm->loaded = ret;
+ if (s->update (s) == B_CANCEL)
+ {
+ *aborted = TRUE;
+ return (-1);
+ }
+ }
+ }
+ }
+
+ return ret;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Write editor buffer content to file
+ *
+ * @param buf pointer to editor buffer
+ * @param fd file descriptor
+ *
+ * @return number of written bytes
+ */
+
+off_t
+edit_buffer_write_file (edit_buffer_t * buf, int fd)
+{
+ off_t ret = 0;
+ off_t i;
+ off_t data_size, sz;
+ void *b;
+
+ /* write all fulfilled parts of b1 from begin to end */
+ if (buf->b1->len != 0)
+ {
+ data_size = EDIT_BUF_SIZE;
+ for (i = 0; i < (off_t) buf->b1->len - 1; i++)
+ {
+ b = g_ptr_array_index (buf->b1, i);
+ sz = mc_write (fd, b, data_size);
+ if (sz >= 0)
+ ret += sz;
+ else if (i == 0)
+ ret = sz;
+ if (sz != data_size)
+ return ret;
+ }
+
+ /* write last partially filled part of b1 */
+ data_size = ((buf->curs1 - 1) & M_EDIT_BUF_SIZE) + 1;
+ b = g_ptr_array_index (buf->b1, i);
+ sz = mc_write (fd, b, data_size);
+ if (sz >= 0)
+ ret += sz;
+ if (sz != data_size)
+ return ret;
+ }
+
+ /* write b2 from end to begin, if b2 contains some data */
+ if (buf->b2->len != 0)
+ {
+ /* write last partially filled part of b2 */
+ i = buf->b2->len - 1;
+ b = g_ptr_array_index (buf->b2, i);
+ data_size = ((buf->curs2 - 1) & M_EDIT_BUF_SIZE) + 1;
+ sz = mc_write (fd, (char *) b + EDIT_BUF_SIZE - data_size, data_size);
+ if (sz >= 0)
+ ret += sz;
+
+ if (sz == data_size)
+ {
+ /* write other fulfilled parts of b2 from end to begin */
+ data_size = EDIT_BUF_SIZE;
+ while (--i >= 0)
+ {
+ b = g_ptr_array_index (buf->b2, i);
+ sz = mc_write (fd, b, data_size);
+ if (sz >= 0)
+ ret += sz;
+ if (sz != data_size)
+ break;
+ }
+ }
+ }
+
+ return ret;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+/**
+ * Calculate percentage of specified character offset
+ *
+ * @param buf pointer to editor buffer
+ * @param p character offset
+ *
+ * @return percentage of specified character offset
+ */
+
+int
+edit_buffer_calc_percent (const edit_buffer_t * buf, off_t offset)
+{
+ int percent;
+
+ if (buf->size == 0)
+ percent = 0;
+ else if (offset >= buf->size)
+ percent = 100;
+ else if (offset > (INT_MAX / 100))
+ percent = offset / (buf->size / 100);
+ else
+ percent = offset * 100 / buf->size;
+
+ return percent;
+}
+
+/* --------------------------------------------------------------------------------------------- */