ladybird/Userland/Utilities/shuf.cpp
2021-10-17 12:07:09 -07:00

61 lines
1.3 KiB
C++

/*
* Copyright (c) 2021, Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Random.h>
#include <AK/String.h>
#include <AK/Vector.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main([[maybe_unused]] int argc, [[maybe_unused]] char** argv)
{
if (pledge("stdio", nullptr) > 0) {
perror("pledge");
return 1;
}
Vector<String> lines;
char* buffer = nullptr;
for (;;) {
size_t n = 0;
errno = 0;
ssize_t buflen = getline(&buffer, &n, stdin);
if (buflen == -1 && errno != 0) {
perror("getline");
exit(1);
}
if (buflen == -1)
break;
lines.append({ buffer, AK::ShouldChomp::Chomp });
}
free(buffer);
if (lines.is_empty())
return 0;
// Fisher-Yates shuffle
String tmp;
for (size_t i = lines.size() - 1; i >= 1; --i) {
size_t j = get_random_uniform(i + 1);
// Swap i and j
if (i == j)
continue;
tmp = move(lines[j]);
lines[j] = move(lines[i]);
lines[i] = move(tmp);
}
for (auto& line : lines) {
fputs(line.characters(), stdout);
fputc('\n', stdout);
}
return 0;
}