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/* 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 <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();
}
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