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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 <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include "edi.h"
static const char Magic[3] = "EDI";
static const char Version = 1;
static enum Error
write(FILE *stream, const void *ptr, size_t size, size_t nitems) {
size_t n = fwrite(ptr, size, nitems, stream);
return (n < nitems ? Errno + errno : Ok);
}
static enum Error writeBuffer(FILE *stream, const struct Buffer *buf) {
size_t len = 0;
const struct Block *block;
for (block = buf->block; block; block = block->prev) {
len += block->len;
}
enum Error error = write(stream, &len, sizeof(len), 1);
if (error) return error;
for (block = buf->block; block; block = block->prev) {
error = write(stream, block->chars, sizeof(wchar_t), block->len);
if (error) return error;
}
return Ok;
}
static enum Error
writeSlice(FILE *stream, const struct Buffer *buf, struct Slice slice) {
size_t offset = 0;
const struct Block *block = buf->block;
while (block) {
if (
slice.ptr >= block->chars && slice.ptr < &block->chars[block->len]
) break;
offset += block->len;
block = block->prev;
}
assert(block);
size_t ptr = offset + (size_t)(slice.ptr - block->chars);
enum Error error = write(stream, &ptr, sizeof(ptr), 1);
if (error) return error;
return write(stream, &slice.len, sizeof(slice.len), 1);
}
static enum Error
writeTable(FILE *stream, const struct Buffer *buf, const struct Table *table) {
enum Error error = write(stream, &table->len, sizeof(table->len), 1);
for (size_t i = 0; i < table->len; ++i) {
error = writeSlice(stream, buf, table->slices[i]);
if (error) return error;
}
return Ok;
}
static enum Error
writeState(FILE *stream, const struct Buffer *buf, const struct State *state) {
enum Error error;
error = write(stream, &state->prev, sizeof(state->prev), 1);
if (error) return error;
error = write(stream, &state->next, sizeof(state->next), 1);
if (error) return error;
return writeTable(stream, buf, &state->table);
}
static enum Error
writeLog(FILE *stream, const struct Buffer *buf, const struct Log *log) {
enum Error error;
error = write(stream, &log->state, sizeof(log->state), 1);
if (error) return error;
error = write(stream, &log->len, sizeof(log->len), 1);
if (error) return error;
for (size_t i = 0; i < log->len; ++i) {
error = writeState(stream, buf, &log->states[i]);
if (error) return error;
}
return Ok;
}
enum Error storeWrite(FILE *stream, const struct Edit *edit) {
enum Error error;
error = write(stream, Magic, sizeof(Magic), 1);
if (error) return error;
error = write(stream, &Version, sizeof(Version), 1);
if (error) return error;
error = writeBuffer(stream, &edit->buf);
if (error) return error;
return writeLog(stream, &edit->buf, &edit->log);
}
static enum Error read(FILE *stream, void *ptr, size_t size, size_t nitems) {
size_t n = fread(ptr, size, nitems, stream);
if (ferror(stream)) return Errno + errno;
return (n < nitems ? StoreEOF : Ok);
}
static enum Error readMagic(FILE *stream) {
char magic[3];
enum Error error = read(stream, magic, sizeof(magic), 1);
if (error) return error;
return (
magic[0] != Magic[0] || magic[1] != Magic[1] || magic[2] != Magic[2]
? StoreMagic
: Ok
);
}
static enum Error readVersion(FILE *stream) {
char version;
enum Error error = read(stream, &version, sizeof(version), 1);
if (error) return error;
return (version != Version ? StoreVersion : Ok);
}
static enum Error readBuffer(FILE *stream, struct Buffer *buf) {
size_t len;
enum Error error = read(stream, &len, sizeof(len), 1);
if (error) return error;
wchar_t *dest = bufferDest(buf, len);
return read(stream, dest, sizeof(wchar_t), len);
}
static enum Error
readSlice(FILE *stream, struct Buffer *buf, struct Table *table) {
enum Error error;
size_t ptr, len;
error = read(stream, &ptr, sizeof(ptr), 1);
if (error) return error;
error = read(stream, &len, sizeof(len), 1);
if (error) return error;
tablePush(table, (struct Slice) { &buf->slice.ptr[ptr], len });
return Ok;
}
static enum Error
readTable(FILE *stream, struct Buffer *buf, struct Table *table) {
size_t len;
enum Error error = read(stream, &len, sizeof(len), 1);
if (error) return error;
*table = tableAlloc(len);
for (size_t i = 0; i < len; ++i) {
error = readSlice(stream, buf, table);
if (error) return error;
}
return Ok;
}
static enum Error
readState(FILE *stream, struct Buffer *buf, size_t offset, struct Log *log) {
enum Error error;
size_t prev, next;
struct Table table;
error = read(stream, &prev, sizeof(prev), 1);
if (error) return error;
error = read(stream, &next, sizeof(next), 1);
if (error) return error;
error = readTable(stream, buf, &table);
if (error) return error;
logPush(log, table);
log->states[log->state].prev = offset + prev;
log->states[log->state].next = offset + next;
return Ok;
}
static enum Error readLog(FILE *stream, struct Buffer *buf, struct Log *log) {
enum Error error;
size_t state, len;
error = read(stream, &state, sizeof(state), 1);
if (error) return error;
error = read(stream, &len, sizeof(len), 1);
if (error) return error;
size_t offset = log->len;
for (size_t i = 0; i < len; ++i) {
error = readState(stream, buf, offset, log);
if (error) return error;
}
log->state = offset + state;
return Ok;
}
enum Error storeRead(FILE *stream, struct Edit *edit) {
enum Error error;
error = readMagic(stream);
if (error) return error;
error = readVersion(stream);
if (error) return error;
error = readBuffer(stream, &edit->buf);
if (error) return error;
return readLog(stream, &edit->buf, &edit->log);
}
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