diff options
Diffstat (limited to 'lib/mbsedit.c')
| -rw-r--r-- | lib/mbsedit.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/lib/mbsedit.c b/lib/mbsedit.c new file mode 100644 index 0000000..ecfa9f4 --- /dev/null +++ b/lib/mbsedit.c @@ -0,0 +1,227 @@ +/* + * SPDX-License-Identifier: LGPL-2.1-or-later + * + * Very simple multibyte buffer editor. Allows to maintaine the current + * position in the string, add and remove chars on the current position. + * + * 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; + +#ifdef HAVE_WIDECHAR + wchar_t wc = (wchar_t) c; + char in_buf[MB_CUR_MAX]; + + n = wctomb(in_buf, wc); + if (n == (size_t) -1) + return n; + *ncells = wcwidth(wc); + in = in_buf; +#else + *ncells = 1; + in = (char *) &c; +#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; +} |