cryptopals-zig/set1/challenge2_fixed_xor/src/main.zig
2022-02-06 22:34:08 +01:00

50 lines
1.6 KiB
Zig

const std = @import("std");
fn readHex(allocator: std.mem.Allocator, reader: anytype, max_size: usize) !?[]u8 {
var resultbuffer = std.ArrayList(u8).init(allocator);
defer resultbuffer.deinit();
while (true) {
const line = try reader.readUntilDelimiterOrEofAlloc(allocator, '\n', max_size * 2);
const hex = line orelse return null;
defer allocator.free(hex);
try resultbuffer.resize(hex.len / 2);
_ = std.fmt.hexToBytes(resultbuffer.items, hex) catch {
std.log.err("not a valid hexadecimal", .{});
continue;
};
return resultbuffer.toOwnedSlice();
}
}
pub fn main() anyerror!void {
var gpa = std.heap.GeneralPurposeAllocator(.{}){};
defer _ = gpa.deinit();
const allocator = gpa.allocator();
const stdin = std.io.bufferedReader(std.io.getStdIn().reader()).reader();
const stdout = std.io.getStdOut().writer();
while (true) {
const input1 = (try readHex(allocator, stdin, 4096)) orelse break;
defer allocator.free(input1);
const input2 = (try readHex(allocator, stdin, 4096)) orelse break;
defer allocator.free(input2);
if (input1.len != input2.len) {
std.log.err("not the same length", .{});
continue;
}
var output = try std.ArrayList(u8).initCapacity(allocator, input1.len);
defer output.deinit();
var i: usize = 0;
while (i < input1.len) : (i += 1) {
try output.append(input1[i] ^ input2[i]);
}
try stdout.print("{}\n", .{std.fmt.fmtSliceHexLower(output.items)});
}
}