Factor out line editing to edit.c

1 files changed, 193 insertions, 0 deletions

diff --git a/edit.c b/edit.c
new file mode 100644
index 0000000..9073f92
--- /dev/null
+++ b/edit.c
@@ -0,0 +1,193 @@
+/* Copyright (C) 2018  Curtis McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include "chat.h"
+
+enum { BUF_LEN = 512 };
+static struct {
+	wchar_t buf[BUF_LEN];
+	wchar_t *ptr;
+	wchar_t *end;
+	wchar_t *tab;
+} line = {
+	.ptr = line.buf,
+	.end = line.buf,
+};
+
+static wchar_t tail;
+const wchar_t *editHead(void) {
+	tail = *line.ptr;
+	*line.ptr = L'\0';
+	return line.buf;
+}
+const wchar_t *editTail(void) {
+	*line.ptr = tail;
+	*line.end = L'\0';
+	return line.ptr;
+}
+
+static void left(void) {
+	if (line.ptr > line.buf) line.ptr--;
+}
+static void right(void) {
+	if (line.ptr < line.end) line.ptr++;
+}
+static void home(void) {
+	line.ptr = line.buf;
+}
+static void end(void) {
+	line.ptr = line.end;
+}
+static void kill(void) {
+	line.end = line.ptr;
+}
+
+static void backspace(void) {
+	if (line.ptr == line.buf) return;
+	if (line.ptr != line.end) {
+		wmemmove(line.ptr - 1, line.ptr, line.end - line.ptr);
+	}
+	line.ptr--;
+	line.end--;
+}
+static void delete(void) {
+	if (line.ptr == line.end) return;
+	right();
+	backspace();
+}
+
+static void insert(wchar_t ch) {
+	if (line.end == &line.buf[BUF_LEN - 1]) return;
+	if (line.ptr != line.end) {
+		wmemmove(line.ptr + 1, line.ptr, line.end - line.ptr);
+	}
+	*line.ptr++ = ch;
+	line.end++;
+}
+
+static void enter(void) {
+	if (line.end == line.buf) return;
+	*line.end = L'\0';
+	char *str = awcstombs(line.buf);
+	if (!str) err(EX_DATAERR, "awcstombs");
+	input(str);
+	free(str);
+	line.ptr = line.buf;
+	line.end = line.buf;
+}
+
+static char *prefix;
+static void complete(void) {
+	if (!line.tab) {
+		editHead();
+		line.tab = wcsrchr(line.buf, L' ');
+		line.tab = (line.tab ? &line.tab[1] : line.buf);
+		prefix = awcstombs(line.tab);
+		if (!prefix) err(EX_DATAERR, "awcstombs");
+		editTail();
+	}
+
+	const char *next = tabNext(prefix);
+	if (!next) return;
+
+	wchar_t *wcs = ambstowcs(next);
+	if (!wcs) err(EX_DATAERR, "ambstowcs");
+
+	size_t i = 0;
+	for (; wcs[i] && line.ptr > &line.tab[i]; ++i) {
+		line.tab[i] = wcs[i];
+	}
+	while (line.ptr > &line.tab[i]) {
+		backspace();
+	}
+	for (; wcs[i]; ++i) {
+		insert(wcs[i]);
+	}
+	free(wcs);
+
+	size_t pos = line.tab - line.buf;
+	if (!pos) {
+		insert(L':');
+	} else if (pos >= 2) {
+		if (line.buf[pos - 2] == L':' || line.buf[pos - 2] == L',') {
+			line.buf[pos - 2] = L',';
+			insert(L':');
+		}
+	}
+	insert(L' ');
+}
+
+static void accept(void) {
+	if (!line.tab) return;
+	line.tab = NULL;
+	free(prefix);
+	tabAccept();
+}
+static void reject(void) {
+	if (!line.tab) return;
+	line.tab = NULL;
+	free(prefix);
+	tabReject();
+}
+
+static bool editMeta(wchar_t ch) {
+	(void)ch;
+	return false;
+}
+
+static bool editCtrl(wchar_t ch) {
+	switch (ch) {
+		break; case L'B': reject(); left();
+		break; case L'F': reject(); right();
+		break; case L'A': reject(); home();
+		break; case L'E': reject(); end();
+		break; case L'D': reject(); delete();
+		break; case L'K': reject(); kill();
+
+		break; case L'C': accept(); insert(IRC_COLOR);
+		break; case L'N': accept(); insert(IRC_RESET);
+		break; case L'O': accept(); insert(IRC_BOLD);
+		break; case L'R': accept(); insert(IRC_COLOR);
+		break; case L'T': accept(); insert(IRC_ITALIC);
+		break; case L'V': accept(); insert(IRC_REVERSE);
+
+		break; default: return false;
+	}
+	return true;
+}
+
+bool edit(bool meta, bool ctrl, wchar_t ch) {
+	if (meta) return editMeta(ch);
+	if (ctrl) return editCtrl(ch);
+	switch (ch) {
+		break; case L'\t': complete();
+		break; case L'\b': reject(); backspace();
+		break; case L'\n': accept(); enter();
+		break; default: {
+			if (!iswprint(ch)) return false;
+			accept();
+			insert(ch);
+		}
+	}
+	return true;
+}