liblinux++

commit 8f2ec1862e588f4e1aefd4c00cdd2726c15fd278
parent 1c825df3826ea8ed91a680b4e05c0610d75b8a5d
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Fri,  9 Jan 2026 20:51:33 +0000

printing numbers

Diffstat:
M
Tupfile
 | 
2
++
M
linux.hpp
 | 
7
+++++++
M
vector.hpp
 | 
2
+-
M
writer.cpp
 | 
59
++++++++++++++++++++++++++++++++++++++++++++++++++++++-----

4 files changed, 64 insertions(+), 6 deletions(-)
diff --git a/Tupfile b/Tupfile
@@ -21,4 +21,6 @@ LDFLAGS = --gc-sections
 
 run ./gen.sh
 
+: bin/writer.aarch64 |> %f |>
+
 .gitignore
diff --git a/linux.hpp b/linux.hpp
@@ -54,6 +54,13 @@ struct span
 	, len{n}
 	{}
 
+	inline span(T* p, T* end) noexcept
+	: ptr{p}
+	, len{static_cast<size_t>(end - p)}
+	{
+		assert(p <= end);
+	}
+
 	template <size_t N>
 	inline span(T (&arr)[N]) noexcept
 	: span{arr, N}
diff --git a/vector.hpp b/vector.hpp
@@ -62,7 +62,7 @@ struct vector
 		T* p = buf + used;
 		for (auto const& x : data)
 			new (p++) T{x};
-		used = p - buf;
+		used += data.size();
 	}
 
 	T const* data() const { return buf; }
diff --git a/writer.cpp b/writer.cpp
@@ -2,6 +2,10 @@
 
 struct writer
 {
+	virtual void write(char const c)
+	{
+		write({&c, 1});
+	}
 	virtual void write(span<char const>) = 0;
 protected:
 	~writer() = default;
@@ -35,15 +39,60 @@ private:
 	vector<char> buffer;
 };
 
+
+constexpr span<char const> operator ""_sp(char const* begin, size_t size)
+{
+	return {begin, size};
+}
+
+template <typename T>
+bool operator == (span<T> lhs, span<T> rhs)
+{
+	if (lhs.size() != rhs.size())
+		return false;
+	for (size_t i = 0; i < lhs.size(); ++i)
+		if (lhs[i] != rhs[i])
+			return false;
+	return true;
+}
+
+
+
+void decimal(writer& w, uint64_t n)
+{
+	char buf[20];
+	char* const end = buf + 16;
+	char* p = end;
+	do
+	{
+		*--p = n % 10 + '0';
+		n /= 10;
+	} while (n);
+	w.write({p, end});
+}
+
+void test(uint64_t x, span<char const> expect)
+{
+	buf_writer w;
+	decimal(w, x);
+	assert(w.get() == expect);
+}
+
+#define tst(x) test(x##LLU, #x ""_sp)
+
 int main()
 {
+	tst(0);
+	tst(9);
+	tst(100);
+	tst(100100);
+	tst(18446744073709551615);
+
 	buf_writer x;
 	writer* w = &x;
-	for (int i = 0; i < 240; ++i)
-	{
-		w->write("Hello, ");
-		w->write("World! Wow what a lovely day!\n");
-	}
+	w->write("Hello, "_sp);
+	decimal(*w, 1234567890);
+	w->write(" World! Wow what a lovely day!\n"_sp);
 	fd_writer cout{stdout};
 	w = &cout;
 	w->write(x.get());