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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2023
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/telegram/files/FileBitmask.h"
#include "td/utils/common.h"
#include "td/utils/misc.h"
#include "td/utils/ScopeGuard.h"
namespace td {
Bitmask::Bitmask(Decode, Slice data) : data_(zero_one_decode(data)) {
}
Bitmask::Bitmask(Ones, int64 count) : data_(narrow_cast<size_t>((count + 7) / 8), '\0') {
for (int64 i = 0; i < count; i++) {
set(i);
}
}
Bitmask Bitmask::compress(int k) const {
Bitmask res;
for (int64 i = 0; i * k < size(); i++) {
bool f = true;
for (int64 j = 0; j < k && f; j++) {
f &= get(i * k + j);
}
if (f) {
res.set(i);
}
}
return res;
}
std::string Bitmask::encode(int32 prefix_count) {
// remove zeroes at the end to make encoding deterministic
Slice data(data_);
int save_i = -1;
char save_c;
if (prefix_count != -1) {
auto truncated_size = (prefix_count + 7) / 8;
data.truncate(truncated_size);
if (prefix_count % 8 != 0) {
save_i = truncated_size - 1;
save_c = data_[save_i];
auto mask = 0xff >> (8 - prefix_count % 8);
data_[save_i] = static_cast<char>(data_[save_i] & mask);
}
}
SCOPE_EXIT {
if (save_i != -1) {
data_[save_i] = save_c;
}
};
while (!data.empty() && data.back() == '\0') {
data.remove_suffix(1);
}
return zero_one_encode(data);
}
int64 Bitmask::get_ready_prefix_size(int64 offset, int64 part_size, int64 file_size) const {
if (offset < 0) {
return 0;
}
if (part_size == 0) {
return 0;
}
CHECK(part_size > 0);
auto offset_part = offset / part_size;
auto ones = get_ready_parts(offset_part);
if (ones == 0) {
return 0;
}
auto ready_parts_end = (offset_part + ones) * part_size;
if (file_size != 0 && ready_parts_end > file_size) {
ready_parts_end = file_size;
if (offset > file_size) {
offset = file_size;
}
}
auto res = ready_parts_end - offset;
CHECK(res >= 0);
return res;
}
int64 Bitmask::get_total_size(int64 part_size, int64 file_size) const {
int64 res = 0;
for (int64 i = 0; i < size(); i++) {
if (get(i)) {
auto from = i * part_size;
auto to = from + part_size;
if (file_size != 0 && file_size < to) {
to = file_size;
}
if (from < to) {
res += to - from;
}
}
}
return res;
}
bool Bitmask::get(int64 offset_part) const {
if (offset_part < 0) {
return false;
}
auto index = narrow_cast<size_t>(offset_part / 8);
if (index >= data_.size()) {
return false;
}
return (static_cast<uint8>(data_[index]) & (1 << static_cast<int>(offset_part % 8))) != 0;
}
int64 Bitmask::get_ready_parts(int64 offset_part) const {
int64 res = 0;
while (get(offset_part + res)) {
res++;
}
return res;
}
std::vector<int32> Bitmask::as_vector() const {
std::vector<int32> res;
auto size = narrow_cast<int32>(data_.size() * 8);
for (int32 i = 0; i < size; i++) {
if (get(i)) {
res.push_back(i);
}
}
return res;
}
void Bitmask::set(int64 offset_part) {
CHECK(offset_part >= 0);
auto need_size = narrow_cast<size_t>(offset_part / 8 + 1);
if (need_size > data_.size()) {
data_.resize(need_size, '\0');
}
data_[need_size - 1] = static_cast<char>(data_[need_size - 1] | (1 << (offset_part % 8)));
}
int64 Bitmask::size() const {
return static_cast<int64>(data_.size()) * 8;
}
StringBuilder &operator<<(StringBuilder &sb, const Bitmask &mask) {
bool prev = false;
int32 cnt = 0;
for (int64 i = 0; i <= mask.size(); i++) {
bool cur = mask.get(i);
if (cur != prev) { // zeros at the end are intentionally skipped
if (cnt < 5) {
while (cnt > 0) {
sb << (prev ? '1' : '0');
cnt--;
}
} else {
sb << (prev ? '1' : '0') << "(x" << cnt << ')';
cnt = 0;
}
}
prev = cur;
cnt++;
}
return sb;
}
} // namespace td
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