i hate this slightly less
This commit is contained in:
200
03/src/main.zig
200
03/src/main.zig
@@ -34,23 +34,19 @@ test "test input part 2" {
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const STATE = enum { waiting, m, u, l, open, d, o, n, open_do, close_do, apo, t, open_dont, close_dont, rewind };
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fn integerUntilDelimiter(reader: anytype, writer: anytype, delimiter: u8, optional_max_size: ?usize) anyerror!void {
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if (optional_max_size) |max_size| {
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for (0..max_size) |_| {
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const byte: u8 = try reader.readByte();
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if (byte == delimiter) return;
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if (byte < '0' or byte > '9') return error.BadCharacter;
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try writer.writeByte(byte);
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fn parseIntFromReader(reader: anytype) anyerror!u64 {
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const f = try reader.readByte();
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if (f < '0' or f > '9') return error.BadCharacter;
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var v: u64 = f - '0';
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while (true) {
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const c = try reader.readByte();
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if (c < '0' or c > '9') {
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break;
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} else {
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v = (v * 10) + (c - '0');
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}
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return error.StreamTooLong;
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} else {
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while (true) {
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const byte: u8 = try reader.readByte();
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if (byte == delimiter) return;
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try writer.writeByte(byte);
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}
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// Can not throw `error.StreamTooLong` since there are no boundary.
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}
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return v;
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}
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fn run2(s: []const u8) !u64 {
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@@ -60,7 +56,6 @@ fn run2(s: []const u8) !u64 {
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var s_fbs = std.io.fixedBufferStream(s);
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var reader = s_fbs.reader();
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var state = STATE.waiting;
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var buf: [1024]u8 = undefined;
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var total: u64 = 0;
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var do_mul: bool = true;
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@@ -68,75 +63,66 @@ fn run2(s: []const u8) !u64 {
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// god i don't know zig at all
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// this is so genuinely awful
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read: while (true) {
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// state transition
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state = sw: {
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break :sw switch (state) {
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STATE.rewind => {
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try s_fbs.seekBy(-1);
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break :sw STATE.waiting;
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},
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const err_state = sw: { break :sw switch (state) {
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STATE.rewind => {
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try s_fbs.seekBy(-1);
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break :sw STATE.waiting;
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},
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STATE.waiting => {
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switch (reader.readByte() catch { break :read; }) {
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'm' => { break :sw STATE.m; },
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'd' => { break :sw STATE.d; },
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else => { break :sw STATE.waiting; },
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}
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},
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STATE.waiting => {
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switch (reader.readByte() catch |e| break :sw e) {
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'm' => { break :sw STATE.m; },
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'd' => { break :sw STATE.d; },
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else => { break :sw STATE.waiting; },
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}
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},
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STATE.m => if (reader.readByte() catch { break :read; } == 'u') STATE.u else STATE.rewind,
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STATE.u => if (reader.readByte() catch { break :read; } == 'l') STATE.l else STATE.rewind,
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STATE.l => if (reader.readByte() catch { break :read; } == '(') STATE.open else STATE.rewind,
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STATE.m => if ((reader.readByte() catch |e| break :sw e) == 'u') STATE.u else STATE.rewind,
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STATE.u => if ((reader.readByte() catch |e| break :sw e) == 'l') STATE.l else STATE.rewind,
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STATE.l => if ((reader.readByte() catch |e| break :sw e) == '(') STATE.open else STATE.rewind,
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STATE.d => if (reader.readByte() catch { break :read; } == 'o') STATE.o else STATE.rewind,
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STATE.o => switch (reader.readByte() catch { break :read; }) {
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'n' => STATE.n,
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'(' => STATE.open_do,
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else => STATE.rewind,
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},
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STATE.n => if (reader.readByte() catch { break :read; } == '\'') STATE.apo else STATE.rewind,
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STATE.apo => if (reader.readByte() catch { break :read; } == 't') STATE.t else STATE.rewind,
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STATE.t => if (reader.readByte() catch { break :read; } == '(') STATE.open_dont else STATE.rewind,
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STATE.d => if ((reader.readByte() catch |e| break :sw e) == 'o') STATE.o else STATE.rewind,
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STATE.o => switch (reader.readByte() catch |e| break :sw e) {
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'n' => STATE.n,
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'(' => STATE.open_do,
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else => STATE.rewind,
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},
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STATE.n => if ((reader.readByte() catch |e| break :sw e) == '\'') STATE.apo else STATE.rewind,
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STATE.apo => if ((reader.readByte() catch |e| break :sw e) == 't') STATE.t else STATE.rewind,
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STATE.t => if ((reader.readByte() catch |e| break :sw e) == '(') STATE.open_dont else STATE.rewind,
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STATE.open_do => if (reader.readByte() catch { break :read; } == ')') STATE.close_do else STATE.rewind,
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STATE.open_dont => if (reader.readByte() catch { break :read; } == ')') STATE.close_dont else STATE.rewind,
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STATE.open_do => if ((reader.readByte() catch |e| break :sw e) == ')') STATE.close_do else STATE.rewind,
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STATE.open_dont => if ((reader.readByte() catch |e| break :sw e) == ')') STATE.close_dont else STATE.rewind,
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STATE.close_do => {
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do_mul = true;
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break :sw STATE.waiting;
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},
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STATE.close_dont => {
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do_mul = false;
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break :sw STATE.waiting;
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},
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STATE.close_do => {
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do_mul = true;
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break :sw STATE.waiting;
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},
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STATE.close_dont => {
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do_mul = false;
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break :sw STATE.waiting;
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},
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STATE.open => {
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var fbs = std.io.fixedBufferStream(&buf);
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integerUntilDelimiter(reader, fbs.writer(), ',', 1024) catch {
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state = STATE.waiting;
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continue :read;
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};
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const num0 = std.fmt.parseInt(u64, fbs.getWritten(), 10) catch {
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state = STATE.waiting;
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continue :read;
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};
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fbs = std.io.fixedBufferStream(&buf);
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integerUntilDelimiter(reader, fbs.writer(), ')', 1024) catch {
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state = STATE.waiting;
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continue :read;
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};
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const num1 = std.fmt.parseInt(u64, fbs.getWritten(), 10) catch {
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state = STATE.waiting;
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continue :read;
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};
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if (do_mul) {
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std.debug.print("{d} {d}\n", .{ num0, num1 });
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total += num0 * num1;
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}
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STATE.open => {
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const num0 = parseIntFromReader(reader) catch |e| break :sw e;
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try s_fbs.seekBy(-1);
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if ((reader.readByte() catch |e| break :sw e) != ',') break :sw error.BadCharacter;
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break :sw STATE.waiting;
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},
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};
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const num1 = parseIntFromReader(reader) catch |e| break :sw e;
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try s_fbs.seekBy(-1);
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if ((reader.readByte() catch |e| break :sw e) != ')') break :sw error.BadCharacter;
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std.debug.print("{d} {d}\n", .{ num0, num1 });
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if (do_mul) total += num0 * num1;
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break :sw STATE.waiting;
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},
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};};
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state = err_state catch |e| switch (e) {
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error.EndOfStream => { break :read; },
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error.BadCharacter => STATE.rewind,
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else => return e
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};
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}
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@@ -150,47 +136,39 @@ fn run1(s: []const u8) !u64 {
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var s_fbs = std.io.fixedBufferStream(s);
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var reader = s_fbs.reader();
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var state = STATE.waiting;
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var buf: [1024]u8 = undefined;
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var total: u64 = 0;
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// i tried a state machine.
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// god i don't know zig at all
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// this is so genuinely awful
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read: while (true) {
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// state transition
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state = sw: {
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break :sw switch (state) {
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STATE.waiting => if (reader.readByte() catch { break :read; } == 'm') STATE.m else STATE.waiting,
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STATE.m => if (reader.readByte() catch { break :read; } == 'u') STATE.u else STATE.waiting,
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STATE.u => if (reader.readByte() catch { break :read; } == 'l') STATE.l else STATE.waiting,
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STATE.l => if (reader.readByte() catch { break :read; } == '(') STATE.open else STATE.waiting,
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const err_state = sw: { break :sw switch (state) {
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STATE.waiting => if ((reader.readByte() catch |e| break :sw e) == 'm') STATE.m else STATE.waiting,
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STATE.m => if ((reader.readByte() catch |e| break :sw e) == 'u') STATE.u else STATE.waiting,
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STATE.u => if ((reader.readByte() catch |e| break :sw e) == 'l') STATE.l else STATE.waiting,
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STATE.l => if ((reader.readByte() catch |e| break :sw e) == '(') STATE.open else STATE.waiting,
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STATE.open => {
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var fbs = std.io.fixedBufferStream(&buf);
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integerUntilDelimiter(reader, fbs.writer(), ',', 1024) catch {
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state = STATE.waiting;
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continue :read;
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};
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const num0 = std.fmt.parseInt(u64, fbs.getWritten(), 10) catch {
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state = STATE.waiting;
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continue :read;
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};
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fbs = std.io.fixedBufferStream(&buf);
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integerUntilDelimiter(reader, fbs.writer(), ')', 1024) catch {
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state = STATE.waiting;
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continue :read;
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};
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const num1 = std.fmt.parseInt(u64, fbs.getWritten(), 10) catch {
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state = STATE.waiting;
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continue :read;
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};
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std.debug.print("{d} {d}\n", .{ num0, num1 });
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total += num0 * num1;
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STATE.open => {
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const num0 = parseIntFromReader(reader) catch |e| break :sw e;
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try s_fbs.seekBy(-1);
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if ((reader.readByte() catch |e| break :sw e) != ',') break :sw error.BadCharacter;
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break :sw STATE.waiting;
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},
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else => STATE.waiting,
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};
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const num1 = parseIntFromReader(reader) catch |e| break :sw e;
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try s_fbs.seekBy(-1);
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if ((reader.readByte() catch |e| break :sw e) != ')') break :sw error.BadCharacter;
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std.debug.print("{d} {d}\n", .{ num0, num1 });
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total += num0 * num1;
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break :sw STATE.waiting;
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},
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else => STATE.waiting,
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};};
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state = err_state catch |e| switch (e) {
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error.EndOfStream => { break :read; },
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error.BadCharacter => STATE.rewind,
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else => return e
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};
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}
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