1 files changed, 186 insertions, 0 deletions

diff --git a/bin/edi.c b/bin/edi.c
new file mode 100644
index 00000000..fd47bc39
--- /dev/null
+++ b/bin/edi.c
@@ -0,0 +1,186 @@
+/* Copyright (C) 2018  June 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 <curses.h>
+#include <err.h>
+#include <fcntl.h>
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+struct Span {
+	char *ptr;
+	size_t len;
+};
+
+static struct Span spanBefore(struct Span span, size_t index) {
+	return (struct Span) { span.ptr, index };
+}
+static struct Span spanAfter(struct Span span, size_t index) {
+	return (struct Span) { span.ptr + index, span.len - index };
+}
+
+static struct Table {
+	struct Table *next;
+	struct Table *prev;
+	size_t len;
+	struct Span span[];
+} *table;
+
+static struct Table *tableNew(size_t cap) {
+	struct Table *next = malloc(sizeof(*next) + cap * sizeof(struct Span));
+	if (!next) err(EX_OSERR, "malloc");
+	next->next = NULL;
+	next->prev = NULL;
+	next->len = 0;
+	return next;
+}
+
+static struct Table *tableSpan(struct Span span) {
+	struct Table *next = tableNew(1);
+	next->len = 1;
+	next->span[0] = span;
+	return next;
+}
+
+static void tableUndo(void) {
+	if (table->prev) table = table->prev;
+}
+static void tableRedo(void) {
+	if (table->next) table = table->next;
+}
+
+static void tableDiscard(void) {
+	struct Table *it = table->next;
+	table->next = NULL;
+	while (it) {
+		struct Table *next = it->next;
+		free(it);
+		it = next;
+	}
+}
+
+static void tablePush(struct Table *next) {
+	tableDiscard();
+	table->next = next;
+	next->prev = table;
+	table = next;
+}
+
+static struct Span *tableInsert(size_t atStart, struct Span span) {
+	// TODO: Handle table->len == 0
+	struct Table *next = tableNew(table->len + 2);
+	struct Span *insert = NULL;
+
+	size_t start = 0;
+	struct Span *nextSpan = next->span;
+	for (size_t i = 0; i < table->len; ++i) {
+		struct Span prevSpan = table->span[i];
+		size_t end = start + prevSpan.len;
+
+		if (atStart > start && atStart < end) {
+			insert = nextSpan + 1;
+			*nextSpan++ = spanBefore(prevSpan, atStart - start);
+			*nextSpan++ = span;
+			*nextSpan++ = spanAfter(prevSpan, atStart - start);
+		} else if (atStart == start) {
+			insert = nextSpan;
+			*nextSpan++ = span;
+			*nextSpan++ = prevSpan;
+		} else {
+			*nextSpan++ = prevSpan;
+		}
+
+		start = end;
+	}
+	next->len = nextSpan - next->span;
+
+	tablePush(next);
+	return insert;
+}
+
+static void tableDelete(size_t atStart, size_t atEnd) {
+	struct Table *next = tableNew(table->len + 1);
+
+	size_t start = 0;
+	struct Span *nextSpan = next->span;
+	for (size_t i = 0; i < table->len; ++i) {
+		struct Span prevSpan = table->span[i];
+		size_t end = start + prevSpan.len;
+
+		if (atStart > start && atEnd < end) {
+			*nextSpan++ = spanBefore(prevSpan, atStart - start);
+			*nextSpan++ = spanAfter(prevSpan, atEnd - start);
+		} else if (atStart > start && atStart < end && atEnd >= end) {
+			*nextSpan++ = spanBefore(prevSpan, atStart - start);
+		} else if (atStart <= start && atEnd < end && atEnd > start) {
+			*nextSpan++ = spanAfter(prevSpan, atEnd - start);
+		} else if (atStart <= start && atEnd >= end) {
+		} else {
+			*nextSpan++ = prevSpan;
+		}
+
+		start = end;
+	}
+	next->len = nextSpan - next->span;
+
+	tablePush(next);
+}
+
+static void curse(void) {
+	setlocale(LC_CTYPE, "");
+	initscr();
+	cbreak();
+	noecho();
+	keypad(stdscr, true);
+	set_escdelay(100);
+}
+
+static void draw(void) {
+	move(0, 0);
+	for (size_t i = 0; i < table->len; ++i) {
+		addnstr(table->span[i].ptr, (int)table->span[i].len);
+	}
+}
+
+int main(int argc, char *argv[]) {
+	if (argc < 2) return EX_USAGE;
+
+	const char *path = argv[1];
+	int fd = open(path, O_RDWR | O_CREAT, 0644);
+	if (fd < 0) err(EX_CANTCREAT, "%s", path);
+
+	struct stat stat;
+	int error = fstat(fd, &stat);
+	if (error) err(EX_IOERR, "%s", path);
+
+	if (stat.st_size) {
+		char *file = mmap(NULL, stat.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+		if (file == MAP_FAILED) err(EX_IOERR, "%s", path);
+		table = tableSpan((struct Span) { file, stat.st_size });
+	} else {
+		table = tableSpan((struct Span) { NULL, 0 });
+	}
+
+	curse();
+	draw();
+	getch();
+	endwin();
+}