diff --git a/.clang-format b/.clang-format
new file mode 100644
index 0000000..1744547
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,8 @@
+---
+BasedOnStyle: Google
+AccessModifierOffset: -4
+ColumnLimit: 120
+IndentWidth: 4
+TabWidth: 4
+UseTab: Always
+
diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
index 1b00cee..23df486 100644
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -1,9 +1,15 @@
 add_executable(1brc
 	main.cxx
+	io.cxx
+	map.cxx
+	tricks.cxx
 )
 target_sources(1brc
 	PUBLIC
 		FILE_SET 1brc_modules TYPE CXX_MODULES FILES
+		io.ixx
+		map.ixx
+		tricks.ixx
 		#		util/logger.ixx
 )
 
diff --git a/source/io.cxx b/source/io.cxx
new file mode 100644
index 0000000..8fbe262
--- /dev/null
+++ b/source/io.cxx
@@ -0,0 +1,69 @@
+module;
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+module io;
+
+import std;
+
+namespace brc {
+
+std::string read_file(const std::filesystem::path& path) {
+	auto file = std::ifstream(path);
+	if (!file.is_open()) {
+		throw std::runtime_error(std::format("could not open file: {}", path.string()));
+	}
+	auto stream = std::stringstream();
+	stream << file.rdbuf();
+	return stream.str();
+}
+
+mapped_file::mapped_file(const std::filesystem::path& path) {
+	const auto file_size = std::filesystem::file_size(path);
+
+	fd = open(path.generic_string().data(), O_RDONLY);
+	data = mmap(nullptr, file_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	length = file_size;
+
+	if (data == MAP_FAILED) {
+		close(fd);
+		throw std::runtime_error("failed to map file");
+	}
+}
+
+mapped_file::mapped_file(mapped_file&& other) noexcept
+	: fd(other.fd), data(std::exchange(other.data, nullptr)), length(other.length) {}
+
+mapped_file& mapped_file::operator=(mapped_file&& other) noexcept {
+	if (&other == this) {
+		return *this;
+	}
+
+	auto moved = std::move(other);
+
+	std::swap(moved.fd, this->fd);
+	std::swap(moved.data, this->data);
+	std::swap(moved.length, this->length);
+
+	return *this;
+}
+
+mapped_file::~mapped_file() {
+	if (data != nullptr) {
+		munmap(data, length);
+		close(fd);
+	}
+}
+
+mapped_file::operator std::string_view() const noexcept {
+	return std::string_view(reinterpret_cast<const char*>(data), length);
+}
+
+std::size_t mapped_file::size() const noexcept { return length; }
+
+}  // namespace brc
diff --git a/source/io.ixx b/source/io.ixx
new file mode 100644
index 0000000..d917e88
--- /dev/null
+++ b/source/io.ixx
@@ -0,0 +1,31 @@
+export module io;
+
+import std;
+
+namespace brc {
+
+export [[nodiscard]] std::string read_file(const std::filesystem::path& path);
+
+export class mapped_file {
+private:
+	int fd;
+	void* data = nullptr;
+	std::size_t length = 0;
+
+public:
+	explicit mapped_file(const std::filesystem::path& path);
+
+	mapped_file(const mapped_file&) = delete;
+	mapped_file& operator=(const mapped_file&) = delete;
+
+	mapped_file(mapped_file&& rhs) noexcept;
+	mapped_file& operator=(mapped_file&& rhs) noexcept;
+
+	~mapped_file();
+
+	operator std::string_view() const noexcept;
+
+	[[nodiscard]] std::size_t size() const noexcept;
+};
+
+}  // namespace brc
diff --git a/source/liburing.ixx b/source/liburing.ixx
new file mode 100644
index 0000000..c1bfa41
--- /dev/null
+++ b/source/liburing.ixx
@@ -0,0 +1,11 @@
+module;
+
+#include <liburing.h>
+
+export module liburing;
+
+namespace uring {
+
+using ::io_uring;
+
+}
diff --git a/source/main.cxx b/source/main.cxx
index 1593f68..7cbeed6 100644
--- a/source/main.cxx
+++ b/source/main.cxx
@@ -1,3 +1,116 @@
 import std;
+import io;
+import map;
+import tricks;
 
-auto main() -> int { std::println("hello world"); }
+auto calculate_boundaries(std::string_view file, std::size_t thread_count) -> std::inplace_vector<std::size_t, 64> {
+	auto bounds = std::inplace_vector<std::size_t, 64>();
+
+	const auto step_estimate = file.size() / thread_count;
+	while (bounds.size() < thread_count) {
+		auto at_guess = file.data() + (step_estimate * (1 + bounds.size()));
+		while (*at_guess++ != '\n') [[likely]] {
+		}
+		bounds.push_back(at_guess - file.data());
+	}
+
+	return bounds;
+}
+
+[[nodiscard]] auto parse_temp(std::string_view sv) {
+	constexpr auto dot_bit_mask = std::uint64_t(0x10101000ULL);
+
+	auto word = std::uint64_t();
+	std::memcpy(&word, sv.data(), sizeof(word));
+
+	const auto decimal_sep_pos = std::countr_zero(~word & dot_bit_mask);
+	const auto dot_byte = decimal_sep_pos / 8;
+	const auto shift = 28 - decimal_sep_pos;
+
+	// I don't trust auto here
+	std::int64_t is_neg = (static_cast<std::int64_t>(~word) << 59) >> 63;
+	std::uint64_t sign_mask = ~(static_cast<std::uint64_t>(is_neg) & 0xFF);
+	std::uint64_t digits = ((word & sign_mask) << shift) & 0xFFFFFFFFFFULL;
+
+	std::int64_t abs_value = ((digits * 0x640a0001ULL) >> 32) & 0x3FF;
+	std::int64_t value = (abs_value ^ is_neg) - is_neg;
+
+	return std::make_pair(static_cast<std::int32_t>(value), dot_byte + 2);
+}
+
+template <std::size_t BatchSize>
+[[nodiscard]] std::inplace_vector<std::pair<std::int32_t, std::size_t>, BatchSize> parse_temp(
+	std::span<const std::string_view> batch) {
+	auto results = std::inplace_vector<std::pair<std::int32_t, std::size_t>, BatchSize>();
+
+	for (std::size_t i = 0; i < batch.size(); ++i) {
+		results.push_back(parse_temp(batch[i]));
+	}
+
+	return results;
+}
+
+void process_chunk(std::string_view chunk, brc::map& results) {
+	auto it = chunk.begin();
+	while (it != chunk.end()) {
+		const auto semicolon = brc::find_delim({it, chunk.end()}, ';');
+		const auto city = std::string_view(it, it + semicolon);
+
+		const auto [value, len] = parse_temp({it + semicolon + 1, chunk.end()});
+
+		results.insert(city, value);
+
+		it = it + semicolon + 1 + len + 1;
+	}
+}
+
+auto main(int argc, char** argv) -> int {
+	if (argc != 2) {
+		std::println("usage: {} <file.txt>", argv[0]);
+		return 1;
+	}
+
+	const auto filename = std::filesystem::path(argv[1]);
+	const auto file = brc::mapped_file(filename);
+	const auto view = std::string_view(file);
+	const auto thread_count = std::thread::hardware_concurrency() / 1;
+
+	const auto boundaries = calculate_boundaries(file, thread_count);
+
+	auto threads = std::vector<std::thread>();
+	auto results = std::vector<brc::map>();
+	for (std::size_t i = 0; i < thread_count; i++) {
+		results.emplace_back(1ull << 10ull);
+	}
+
+	for (std::size_t i = 0; i < thread_count; i++) {
+		const auto begin = i == 0 ? 0 : boundaries[i - 1];
+		const auto end = boundaries[i];
+		const auto sv = std::string_view(view.begin() + begin, view.begin() + end);
+		threads.emplace_back([i, sv, &results]() { process_chunk(sv, results[i]); });
+	}
+
+	for (std::size_t i = 0; i < thread_count; i++) {
+		threads[i].join();
+	}
+
+	for (std::size_t i = 1; i < results.size(); i++) {
+		results[0].merge_against(results[i]);
+	}
+
+	const auto& map = results[0];
+	const auto entries = map.collapse();
+	std::print("{{");
+	for (auto it = entries.begin(); it != entries.end(); it++) {
+		const auto entry = *it;
+		const auto name = std::string_view(entry.key_ptr, entry.key_len);
+		const auto min = entry.min / 10.0f;
+		const auto mean = (entry.total / entry.count) / 10.0f;
+		const auto max = entry.max / 10.0f;
+		std::print("{}={:.1f}/{:.1f}/{:.1f}", name, min, mean, max);
+		if (it + 1 != entries.end()) {
+			std::print(",");
+		}
+	}
+	std::print("}}");
+}
diff --git a/source/map.cxx b/source/map.cxx
new file mode 100644
index 0000000..445f1e1
--- /dev/null
+++ b/source/map.cxx
@@ -0,0 +1,84 @@
+module map;
+
+import std;
+
+namespace brc {
+
+map::map(std::size_t entry_count) : entries(std::make_unique<entry[]>(entry_count)), entry_count(entry_count) {}
+
+std::uint64_t map::get_key(std::string_view city) noexcept {
+	std::uint64_t raw = 0;
+	const auto data_count = std::min(static_cast<int>(city.size()), 8);
+	std::memcpy(&raw, city.data(), data_count);
+
+	raw *= 0x9E3779B97F4A7C15ULL;
+	return raw ^ (raw >> 32);
+}
+
+std::uint64_t map::get_index(std::string_view city) const noexcept {
+	const auto key = get_key(city);
+	auto index = key & (entry_count - 1);
+
+	while (true) {
+		auto& e = entries[index];
+		if (e.key_ptr == nullptr) {
+			e.key_hash = key;
+			e.key_ptr = city.data();
+			e.key_len = static_cast<std::uint16_t>(city.size());
+			break;
+		} else if (key == e.key_hash && city == std::string_view(e.key_ptr, e.key_len)) {
+			break;
+		}
+		index = (index + 1 == entry_count) ? 0 : index + 1;
+	}
+
+	return index;
+}
+
+void map::insert(std::string_view city, std::int32_t measurement) {
+	const auto index = get_index(city);
+
+	auto& entry = entries[index];
+	entry.count += 1;
+	entry.total += measurement;
+	entry.min = std::min(entry.min, measurement);
+	entry.max = std::max(entry.max, measurement);
+}
+
+void map::merge_against(const map& other) {
+	for (std::size_t i = 0; i < other.entry_count; i++) {
+		if (other.entries[i].key_ptr == nullptr) {
+			continue;
+		}
+
+		auto& other_entry = other.entries[i];
+		auto& our_entry = entries[get_index(std::string_view(other_entry.key_ptr, other_entry.key_len))];
+		our_entry.min = std::min(our_entry.min, other_entry.min);
+		our_entry.max = std::max(our_entry.max, other_entry.max);
+		our_entry.count += other_entry.count;
+		our_entry.total += other_entry.total;
+	}
+}
+
+std::vector<entry> map::collapse() const noexcept {
+	auto data = std::vector<entry>();
+	data.reserve(entry_count);
+
+	for (std::size_t i = 0; i < entry_count; i++) {
+		if (entries[i].key_ptr == nullptr) {
+			continue;
+		}
+
+		data.push_back(entries[i]);
+	}
+
+	std::sort(data.begin(), data.end(), [](const entry& a, const entry& b) {
+		const auto a_sv = std::string_view(a.key_ptr, a.key_len);
+		const auto b_sv = std::string_view(b.key_ptr, b.key_len);
+		return a_sv < b_sv;
+	});
+
+	return data;
+}
+
+}  // namespace brc
diff --git a/source/map.ixx b/source/map.ixx
new file mode 100644
index 0000000..38e9f77
--- /dev/null
+++ b/source/map.ixx
@@ -0,0 +1,38 @@
+export module map;
+
+import std;
+
+namespace brc {
+
+export struct entry {
+	std::uint64_t key_hash = 0;
+	const char* key_ptr = nullptr;								  // 8, 8
+	std::int64_t total = 0;										  // 8, 26
+	std::int32_t min = std::numeric_limits<std::int32_t>::max();  // 4, 12
+	std::int32_t max = std::numeric_limits<std::int32_t>::min();  // 4, 16
+	std::uint32_t count = 0;									  // 4, 30
+	std::uint16_t key_len = 0;									  // 2, 32
+};
+
+export class map {
+private:
+	std::size_t entry_count;
+	std::unique_ptr<entry[]> entries;
+
+	[[nodiscard]] static std::uint64_t get_key(std::string_view city) noexcept;
+
+	[[nodiscard]] std::uint64_t get_index(std::string_view city) const noexcept;
+
+public:
+	explicit map(std::size_t entry_count);
+
+	void insert(std::string_view city, std::int32_t measurement);
+
+	[[nodiscard]] entry& operator[](std::string_view city);
+
+	void merge_against(const map& other);
+
+	[[nodiscard]] std::vector<entry> collapse() const noexcept;
+};
+
+}  // namespace brc
diff --git a/source/tricks.cxx b/source/tricks.cxx
new file mode 100644
index 0000000..14d0b2a
--- /dev/null
+++ b/source/tricks.cxx
@@ -0,0 +1,64 @@
+module;
+
+#include <simd>
+
+module tricks;
+
+import std;
+
+namespace brc {
+
+std::size_t find_delim(std::string_view string, char target) {
+	constexpr auto width = std::simd::vec<std::uint8_t>::size();
+	const auto needle = std::simd::vec<std::uint8_t>(static_cast<std::uint8_t>(target));
+
+	auto i = std::size_t(0);
+	for (; i + width <= string.size(); i += width) {
+		const auto chunk = std::simd::vec<std::uint8_t>(
+			std::span<const std::uint8_t, width>(reinterpret_cast<const std::uint8_t*>(string.data() + i), width));
+
+		const auto mask = chunk == needle;
+		if (const auto bits = mask.to_bitset(); bits.any()) {
+			return i + std::countr_zero(bits.to_ullong());
+		}
+	}
+
+	for (; i < string.size(); ++i) {
+		if (string[i] == target) return i;
+	}
+	return string.size();
+}
+
+std::inplace_vector<std::size_t, 4> find_delim_batch(std::string_view string, char target) {
+	constexpr auto BatchSize = 4;
+	auto sizes = std::inplace_vector<std::size_t, BatchSize>();
+
+	constexpr auto width = std::simd::vec<std::uint8_t>::size();
+	const auto needle = std::simd::vec<std::uint8_t>(static_cast<std::uint8_t>(target));
+
+	std::size_t i = 0;
+
+	for (; i + width <= string.size() && sizes.size() < BatchSize; i += width) {
+		const auto chunk = std::simd::vec<std::uint8_t>(
+			std::span<const std::uint8_t, width>(reinterpret_cast<const std::uint8_t*>(string.data() + i), width));
+
+		const auto mask = chunk == needle;
+		auto bits = mask.to_bitset().to_ullong();
+
+		while (bits != 0 && sizes.size() < BatchSize) {
+			const auto bit_pos = std::countr_zero(bits);
+			sizes.push_back(i + bit_pos);
+			bits &= bits - 1;
+		}
+	}
+
+	for (; i < string.size() && sizes.size() < BatchSize; ++i) {
+		if (string[i] == target) {
+			sizes.push_back(i);
+		}
+	}
+
+	return sizes;
+}
+
+}  // namespace brc
diff --git a/source/tricks.ixx b/source/tricks.ixx
new file mode 100644
index 0000000..106b416
--- /dev/null
+++ b/source/tricks.ixx
@@ -0,0 +1,11 @@
+export module tricks;
+
+import std;
+
+namespace brc {
+
+export [[nodiscard]] std::size_t find_delim(std::string_view string, char target);
+
+export [[nodiscard]] std::inplace_vector<std::size_t, 4> find_delim_batch(std::string_view string, char target);
+
+}  // namespace brc