From ff5af2689a481444645b55f0537be77a13d59aa9 Mon Sep 17 00:00:00 2001
From: Edward Amsden <edward@blackriversoft.com>
Date: Tue, 27 Feb 2024 13:18:18 -0600
Subject: [PATCH] add format-to-cord implementation and flog! macro

---
 rust/ares/src/flog.rs | 73 +++++++++++++++++++++++++++++++++++++++++++
 rust/ares/src/lib.rs  |  1 +
 2 files changed, 74 insertions(+)
 create mode 100644 rust/ares/src/flog.rs

diff --git a/rust/ares/src/flog.rs b/rust/ares/src/flog.rs
new file mode 100644
index 0000000..11d2343
--- /dev/null
+++ b/rust/ares/src/flog.rs
@@ -0,0 +1,73 @@
+use crate::mem::NockStack;
+use crate::noun::{Atom, IndirectAtom};
+use crate::interpreter::Context;
+use std::io::{Write, Result};
+use std::fmt::Arguments;
+
+struct NockWriter<'s, 'b> {
+    stack: &'s mut NockStack,
+    buffer: &'b mut [u8],
+    indirect: IndirectAtom,
+    cursor: usize, //bytes
+}
+
+const INITIAL_CAPACITY_BYTES: usize = 256;
+
+impl<'s, 'b> NockWriter<'s, 'b> {
+    unsafe fn new(stack: &'s mut NockStack) -> Self {
+        let (indirect, buffer) = IndirectAtom::new_raw_mut_bytes(stack, INITIAL_CAPACITY_BYTES);
+        NockWriter {
+            stack,
+            buffer,
+            indirect,
+            cursor: 0,
+        }
+    }
+
+    unsafe fn finalize(mut self) -> Atom {
+        self.indirect.normalize_as_atom()
+    }
+
+    unsafe fn expand(&mut self) {
+        let sz = self.buffer.len();
+        let (new_indirect, new_buffer) = IndirectAtom::new_raw_mut_bytes(self.stack, sz * 2);
+        new_buffer[0..sz].copy_from_slice(self.buffer);
+        self.buffer = new_buffer;
+        self.indirect = new_indirect;
+    }
+}
+
+impl Write for NockWriter<'_, '_> {
+    fn write(&mut self, buf: &[u8]) -> Result<usize> {
+        let sz = buf.len();
+        while (self.buffer.len() - self.cursor) < sz {
+            unsafe { self.expand() };
+        }
+        self.buffer[self.cursor..self.cursor + sz].copy_from_slice(buf);
+        self.cursor += sz;
+        Ok(sz)
+    }
+
+    fn flush(&mut self) -> Result<()> {
+        Ok(())
+    }
+}
+
+pub fn nock_fmt(context: &mut Context, fmt: Arguments<'_>) -> Result<Atom> {
+    let mut nw = unsafe { NockWriter::new(&mut context.stack) };
+    nw.write_fmt(fmt)?;
+    Ok(unsafe { nw.finalize() })
+}
+
+pub fn flog_fmt(context: &mut Context, fmt: Arguments<'_>) -> Result<()> {
+    let cord = nock_fmt(context, fmt)?;
+    context.newt.flog(&mut context.stack, cord.as_noun());
+    Ok(())
+}
+
+#[macro_export]
+macro_rules! flog {
+    ($ctx:expr, $($arg:tt)*) => {
+        $crate::flog::flog_fmt($ctx, std::format_args!($($arg)*))
+    }
+}
diff --git a/rust/ares/src/lib.rs b/rust/ares/src/lib.rs
index d6f6391..f34d51a 100644
--- a/rust/ares/src/lib.rs
+++ b/rust/ares/src/lib.rs
@@ -4,6 +4,7 @@ extern crate lazy_static;
 #[macro_use]
 extern crate static_assertions;
 pub mod guard;
+pub mod flog;
 pub mod hamt;
 pub mod interpreter;
 pub mod jets;