Add a new container: bitvec

examples/0013.graph/shortest_path/spfa_optimize_fastio_bitvec.cc

@@ -0,0 +1,64 @@
+#include <fast_io.h>
+#include <fast_io_device.h>
+#include <fast_io_dsal/queue.h>
+#include <fast_io_dsal/vector.h>
+#include <fast_io_dsal/bitvec.h>
+#include <fast_io_driver/timer.h>
+
+struct node
+{
+	std::size_t to, weight;
+};
+
+using namespace fast_io::io;
+
+int main()
+{
+	::fast_io::timer timer(u8"spfa_optimize_fastio_bitvec");
+	fast_io::ibuf_file ibf("graph.txt");
+	std::size_t m, n;
+	scan(ibf, m, n);
+	::fast_io::vector<::fast_io::vector<node>> graph(n);
+	std::size_t const average{(m / n + 1) * 13 / 10};
+	for (auto &v : graph)
+	{
+		v.reserve(average);
+	}
+	for (std::size_t i{}; i != m; ++i)
+	{
+		std::size_t a, b, w;
+		scan(ibf, a, b, w);
+		graph[a].push_back({b, w});
+	}
+	::fast_io::vector<std::size_t> relax(n, SIZE_MAX);
+	::fast_io::bitvec occupied(n);
+	::fast_io::queue<std::size_t> queue;
+	occupied.set_front();
+	for (queue.push(relax.front() = 0); !queue.is_empty(); queue.pop())
+	{
+		auto front{queue.front()};
+		auto minimum_weight{relax[front]};
+		for (auto e : graph[front])
+		{
+			if (minimum_weight + e.weight < relax[e.to])
+			{
+				relax[e.to] = minimum_weight + e.weight;
+				if (!occupied.test(e.to))
+				{
+					occupied.set(e.to);
+					queue.push(e.to);
+				}
+			}
+		}
+		occupied.reset(front);
+	}
+	fast_io::obuf_file obf("spfa.txt");
+	if (relax.back() == SIZE_MAX)
+	{
+		print(obf, "no answer\n");
+	}
+	else
+	{
+		println(obf, relax.back());
+	}
+}

fuzzing/0007.containers/bitvec/bitvec.cc

@@ -0,0 +1,37 @@
+#include <cstdint>
+#include <fast_io_dsal/bitvec.h>
+
+extern "C" int LLVMFuzzerTestOneInput(uint8_t const *data, size_t size)
+{
+	fast_io::bitvec bv;
+
+	// Push all bits from input
+	for (size_t i = 0; i != size; ++i)
+	{
+		bv.push_back((data[i] & 1) != 0);
+	}
+
+	if (bv.size() > 8)
+	{
+		// Save original bits 1..7
+		bool saved[7];
+		for (size_t i = 1; i != 8; ++i)
+		{
+			saved[i - 1] = bv.test(i);
+		}
+
+		// Mutate front bit
+		bv.set_front_unchecked(true);
+
+		// Check if bits 1..7 changed (they SHOULD NOT)
+		for (size_t i = 1; i != 8; ++i)
+		{
+			if (bv.test(i) != saved[i - 1])
+			{
+				__builtin_trap(); // crash → libFuzzer finds bug
+			}
+		}
+	}
+
+	return 0;
+}

include/fast_io_dsal/bitvec.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#if !defined(__cplusplus)
+#error "You must be using a C++ compiler"
+#endif
+
+#include <version>
+#include <type_traits>
+#include <concepts>
+#include <limits>
+#include <cstdint>
+#include <cstddef>
+#include <new>
+#include <initializer_list>
+#include <bit>
+#include <compare>
+#include <algorithm>
+#include "impl/misc/push_macros.h"
+#include "impl/misc/push_warnings.h"
+#include "../fast_io_core_impl/freestanding/impl.h"
+#include "../fast_io_core_impl/terminate.h"
+#include "../fast_io_core_impl/intrinsics/msvc/impl.h"
+#include "../fast_io_core_impl/allocation/impl.h"
+#include "../fast_io_core_impl/asan_support.h"
+
+#if defined(_MSC_VER) && !defined(__clang__)
+#include <cstring>
+#endif
+
+#include "impl/freestanding.h"
+#include "impl/common.h"
+#include "impl/bitvec.h"
+
+#if ((__STDC_HOSTED__ == 1 && (!defined(_GLIBCXX_HOSTED) || _GLIBCXX_HOSTED == 1) && \
+	  !defined(_LIBCPP_FREESTANDING)) ||                                             \
+	 defined(FAST_IO_ENABLE_HOSTED_FEATURES))
+
+namespace fast_io
+{
+
+using bitvec = ::fast_io::containers::bitvec<::fast_io::native_global_allocator>;
+
+namespace tlc
+{
+using bitvec = ::fast_io::containers::bitvec<::fast_io::native_thread_local_allocator>;
+} // namespace tlc
+
+} // namespace fast_io
+
+#endif
+
+#include "impl/misc/pop_macros.h"
+#include "impl/misc/pop_warnings.h"