more idiomatic full range loops

set1/challenge2_fixed_xor/src/main.zig

@@ -1,17 +1,15 @@
 const std = @import("std");
 
-fn readHex(allocator: std.mem.Allocator, max_size: usize) ![]u8 {
-    const stdin = std.io.bufferedReader(std.io.getStdIn().reader()).reader();
-
-    var inputbuffer = std.ArrayList(u8).init(allocator);
-    defer inputbuffer.deinit();
+fn readHex(allocator: std.mem.Allocator, reader: anytype, max_size: usize) !?[]u8 {
     var resultbuffer = std.ArrayList(u8).init(allocator);
     defer resultbuffer.deinit();
 
     while (true) {
-        try stdin.readUntilDelimiterArrayList(&inputbuffer, '\n', max_size * 2);
-        try resultbuffer.resize(inputbuffer.items.len / 2);
-        _ = std.fmt.hexToBytes(resultbuffer.items, inputbuffer.items) catch {
+        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;
         };
@@ -23,13 +21,14 @@ 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, 4096);
+        const input1 = (try readHex(allocator, stdin, 4096)) orelse break;
         defer allocator.free(input1);
 
-        const input2 = try readHex(allocator, 4096);
+        const input2 = (try readHex(allocator, stdin, 4096)) orelse break;
         defer allocator.free(input2);
 
         if (input1.len != input2.len) {

set1/challenge3_xor_cipher/src/main.zig

@@ -1,17 +1,15 @@
 const std = @import("std");
 
-fn readHex(allocator: std.mem.Allocator, max_size: usize) ![]u8 {
-    const stdin = std.io.bufferedReader(std.io.getStdIn().reader()).reader();
-
-    var inputbuffer = std.ArrayList(u8).init(allocator);
-    defer inputbuffer.deinit();
+fn readHex(allocator: std.mem.Allocator, reader: anytype, max_size: usize) !?[]u8 {
     var resultbuffer = std.ArrayList(u8).init(allocator);
     defer resultbuffer.deinit();
 
     while (true) {
-        try stdin.readUntilDelimiterArrayList(&inputbuffer, '\n', max_size * 2);
-        try resultbuffer.resize(inputbuffer.items.len / 2);
-        _ = std.fmt.hexToBytes(resultbuffer.items, inputbuffer.items) catch {
+        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;
         };
@@ -42,10 +40,11 @@ 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 ciphertext = try readHex(allocator, 4096);
+        const ciphertext = (try readHex(allocator, stdin, 4096)) orelse break;
         defer allocator.free(ciphertext);
 
         var plaintext = try allocator.alloc(u8, ciphertext.len);
@@ -53,7 +52,7 @@ pub fn main() anyerror!void {
         var bestkey: u8 = 0;
         var bestscore: u32 = 0;
         var key: u8 = 0;
-        while (true) {
+        while (true) : (key += 1) {
             decrypt(plaintext, ciphertext, key);
             const s = score(plaintext);
             if (s > bestscore) {
@@ -61,7 +60,7 @@ pub fn main() anyerror!void {
                 bestscore = s;
             }
             key +%= 1;
-            if (key == 0) {
+            if (key == std.math.maxInt(u8)) {
                 break;
             }
         }

set1/challenge4_detect_xor/src/main.zig

@@ -43,8 +43,8 @@ pub fn main() anyerror!void {
     const stdin = std.io.bufferedReader(std.io.getStdIn().reader()).reader();
     const stdout = std.io.getStdOut().writer();
 
-    var bestplaintext = try allocator.alloc(u8, 0);
-    defer allocator.free(bestplaintext);
+    var bestplaintext = std.ArrayList(u8).init(allocator);
+    defer bestplaintext.deinit();
     var bestscore: u32 = 0;
 
     while (true) {
@@ -54,21 +54,19 @@ pub fn main() anyerror!void {
         var plaintext = try allocator.alloc(u8, ciphertext.len);
         defer allocator.free(plaintext);
         var key: u8 = 0;
-        while (true) {
+        while (true) : (key += 1) {
             decrypt(plaintext, ciphertext, key);
             const s = score(plaintext);
             if (s > bestscore) {
-                allocator.free(bestplaintext);
-                bestplaintext = try allocator.alloc(u8, plaintext.len);
-                std.mem.copy(u8, bestplaintext, plaintext);
+                try bestplaintext.resize(plaintext.len);
+                std.mem.copy(u8, bestplaintext.items, plaintext);
                 bestscore = s;
             }
-            key +%= 1;
-            if (key == 0) {
+            if (key == std.math.maxInt(u8)) {
                 break;
             }
         }
     }
 
-    try stdout.print("{s}\n", .{bestplaintext});
+    try stdout.print("{s}\n", .{bestplaintext.items});
 }

set1/challenge5_repeating_xor/5.txt

@@ -0,0 +1,2 @@
+Burning 'em, if you ain't quick and nimble
+I go crazy when I hear a cymbal

set1/challenge5_repeating_xor/build.zig

@@ -0,0 +1,27 @@
+const std = @import("std");
+
+pub fn build(b: *std.build.Builder) void {
+    // Standard target options allows the person running `zig build` to choose
+    // what target to build for. Here we do not override the defaults, which
+    // means any target is allowed, and the default is native. Other options
+    // for restricting supported target set are available.
+    const target = b.standardTargetOptions(.{});
+
+    // Standard release options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall.
+    const mode = b.standardReleaseOptions();
+
+    const exe = b.addExecutable("challenge5_repeating_xor", "src/main.zig");
+    exe.setTarget(target);
+    exe.setBuildMode(mode);
+    exe.install();
+
+    const run_cmd = exe.run();
+    run_cmd.step.dependOn(b.getInstallStep());
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+}

set1/challenge5_repeating_xor/src/main.zig

@@ -0,0 +1,21 @@
+const std = @import("std");
+
+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();
+
+    const key = "ICE";
+    const input = try stdin.readAllAlloc(allocator, 4096);
+    defer allocator.free(input);
+
+    var i: usize = 0;
+    for (input) |*char| {
+        char.* ^= key[i];
+        i = (i + 1) % key.len;
+    }
+
+    try stdout.print("{s}\n", .{std.fmt.fmtSliceHexLower(input)});
+}