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lib/mbsedit: add simple buffer editor

Signed-off-by: Karel Zak <kzak@redhat.com>
pull/416/head
Karel Zak 6 years ago
parent
commit
299ef2c457
  1. 32
      include/mbsedit.h
  2. 1
      lib/Makemodule.am
  3. 222
      lib/mbsedit.c

32
include/mbsedit.h

@ -0,0 +1,32 @@
#ifndef UTIL_LINUX_MBSEDIT_H
# define UTIL_LINUX_MBSEDIT_H
#include "mbsalign.h"
#include "widechar.h"
struct mbs_editor {
char *buf; /* buffer */
size_t max_bytes; /* size of the buffer */
size_t max_cells; /* maximal allowed number of cells */
size_t cur_cells; /* number of cells to print the buffer */
size_t cur_bytes; /* number of chars in bytes */
size_t cursor; /* cursor position in bytes */
size_t cursor_cells; /* cursor position in cells */
};
enum {
MBS_EDIT_LEFT,
MBS_EDIT_RIGHT,
MBS_EDIT_END,
MBS_EDIT_HOME
};
struct mbs_editor *mbs_new_edit(char *buf, size_t bufsz, size_t ncells);
char *mbs_free_edit(struct mbs_editor *edit);
int mbs_edit_goto(struct mbs_editor *edit, int where);
int mbs_edit_delete(struct mbs_editor *edit);
int mbs_edit_backspace(struct mbs_editor *edit);
int mbs_edit_insert(struct mbs_editor *edit, wint_t c);
#endif /* UTIL_LINUX_MBSEDIT_H */

1
lib/Makemodule.am

@ -13,6 +13,7 @@ libcommon_la_SOURCES = \
lib/mangle.c \
lib/match.c \
lib/mbsalign.c \
lib/mbsedit.c\
lib/md5.c \
lib/pager.c \
lib/path.c \

222
lib/mbsedit.c

@ -0,0 +1,222 @@
/*
* Very simple multibyte buffer editor. Allows to maintaine the current
* possition in the string, add and remove chars on the current possition.
*
* This file may be distributed under the terms of the
* GNU Lesser General Public License.
*
* Copyright (C) 2017 Karel Zak <kzak@redhat.com>
*/
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include "mbsalign.h"
#include "mbsedit.h"
struct mbs_editor *mbs_new_edit(char *buf, size_t bufsz, size_t ncells)
{
struct mbs_editor *edit = calloc(1, sizeof(*edit));
if (edit) {
edit->buf = buf;
edit->max_bytes = bufsz;
edit->max_cells = ncells;
edit->cur_cells = mbs_safe_width(buf);
edit->cur_bytes = strlen(buf);
}
return edit;
}
char *mbs_free_edit(struct mbs_editor *edit)
{
char *ret = edit ? edit->buf : NULL;
free(edit);
return ret;
}
static size_t mbs_next(const char *str, size_t *ncells)
{
#ifdef HAVE_WIDECHAR
wchar_t wc;
size_t n = 0;
if (!str || !*str)
return 0;
n = mbrtowc(&wc, str, MB_CUR_MAX, NULL);
*ncells = wcwidth(wc);
return n;
#else
if (!str || !*str)
return 0;
*ncells = 1;
return 1;
#endif
}
static size_t mbs_prev(const char *start, const char *end, size_t *ncells)
{
#ifdef HAVE_WIDECHAR
wchar_t wc = 0;
const char *p, *prev;
size_t n = 0;
if (!start || !end || start == end || !*start)
return 0;
prev = p = start;
while (p < end) {
n = mbrtowc(&wc, p, MB_CUR_MAX, NULL);
prev = p;
if (n == (size_t) -1 || n == (size_t) -2)
p++;
else
p += n;
}
if (prev == end)
return 0;
*ncells = wcwidth(wc);
return n;
#else
if (!start || !end || start == end || !*start)
return 0;
*ncells = 1;
return 1;
#endif
}
int mbs_edit_goto(struct mbs_editor *edit, int where)
{
switch (where) {
case MBS_EDIT_LEFT:
if (edit->cursor == 0)
return 1;
else {
size_t n, cells;
n = mbs_prev(edit->buf, edit->buf + edit->cursor, &cells);
if (n) {
edit->cursor -= n;
edit->cursor_cells -= cells;
}
}
break;
case MBS_EDIT_RIGHT:
if (edit->cursor_cells >= edit->cur_cells)
return 1;
else {
size_t n, cells;
n = mbs_next(edit->buf + edit->cursor, &cells);
if (n) {
edit->cursor += n;
edit->cursor_cells += cells;
}
}
break;
case MBS_EDIT_HOME:
edit->cursor = 0;
edit->cursor_cells = 0;
break;
case MBS_EDIT_END:
edit->cursor = edit->cur_bytes;
edit->cursor_cells = edit->cur_cells;
break;
default:
return -EINVAL;
}
return 0;
}
/* Remove next MB from @str, returns number of removed bytes */
static size_t remove_next(char *str, size_t *ncells)
{
/* all in bytes! */
size_t bytes, move_bytes, n;
n = mbs_next(str, ncells);
bytes = strlen(str);
move_bytes = bytes - n;
memmove(str, str + n, move_bytes);
str[bytes - n] = '\0';
return n;
}
static size_t mbs_insert(char *str, wint_t c, size_t *ncells)
{
/* all in bytes! */
size_t n = 1, bytes;
char *in = (char *) &c;
#ifdef HAVE_WIDECHAR
wchar_t wc = (wchar_t) c;
char in_buf[MB_CUR_MAX];
n = wctomb(in_buf, wc);
*ncells = wcwidth(wc);
in = in_buf;
#else
*ncells = 1;
#endif
bytes = strlen(str);
memmove(str + n, str, bytes);
memcpy(str, in, n);
str[bytes + n] = '\0';
return n;
}
static int mbs_edit_remove(struct mbs_editor *edit)
{
size_t n, ncells;
if (edit->cur_cells == 0 || edit->cursor >= edit->cur_bytes)
return 1;
n = remove_next(edit->buf + edit->cursor, &ncells);
if (n == (size_t)-1)
return 1;
edit->cur_bytes -= n;
edit->cur_cells = mbs_safe_width(edit->buf);
return 0;
}
int mbs_edit_delete(struct mbs_editor *edit)
{
if (edit->cursor >= edit->cur_bytes
&& mbs_edit_goto(edit, MBS_EDIT_LEFT) == 1)
return 1;
return mbs_edit_remove(edit);
}
int mbs_edit_backspace(struct mbs_editor *edit)
{
if (mbs_edit_goto(edit, MBS_EDIT_LEFT) == 0)
return mbs_edit_remove(edit);
return 1;
}
int mbs_edit_insert(struct mbs_editor *edit, wint_t c)
{
size_t n, ncells;
if (edit->cur_bytes + MB_CUR_MAX > edit->max_bytes)
return 1;
n = mbs_insert(edit->buf + edit->cursor, c, &ncells);
if (n == (size_t)-1)
return 1;
edit->cursor += n;
edit->cursor_cells += ncells;
edit->cur_bytes += n;
edit->cur_cells = mbs_safe_width(edit->buf);
return 0;
}
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