From 95981e00ff45dae4f87c2ecb4c4fecde6e437fda Mon Sep 17 00:00:00 2001
From: Sean Smith <scsmithr@gmail.com>
Date: Sat, 21 Dec 2024 09:45:35 -0600
Subject: [PATCH] iterutil crate

---
 Cargo.lock                                 |  5 +++++
 crates/iterutil/Cargo.toml                 |  6 ++++++
 crates/iterutil/src/exact_size.rs          | 25 ++++++++++++++++++++++
 crates/iterutil/src/lib.rs                 |  1 +
 crates/rayexec_execution/Cargo.toml        |  1 +
 crates/rayexec_execution/src/arrays/mod.rs |  1 +
 crates/rayexec_execution/src/lib.rs        |  1 +
 7 files changed, 40 insertions(+)
 create mode 100644 crates/iterutil/Cargo.toml
 create mode 100644 crates/iterutil/src/exact_size.rs
 create mode 100644 crates/iterutil/src/lib.rs
 create mode 100644 crates/rayexec_execution/src/arrays/mod.rs

diff --git a/Cargo.lock b/Cargo.lock
index ee9d2aca1..e51d89c02 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1391,6 +1391,10 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "iterutil"
+version = "0.0.93"
+
 [[package]]
 name = "itoa"
 version = "1.0.10"
@@ -2270,6 +2274,7 @@ dependencies = [
  "half",
  "hashbrown 0.14.5",
  "indexmap",
+ "iterutil",
  "num-traits",
  "num_cpus",
  "once_cell",
diff --git a/crates/iterutil/Cargo.toml b/crates/iterutil/Cargo.toml
new file mode 100644
index 000000000..39c919663
--- /dev/null
+++ b/crates/iterutil/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "iterutil"
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
diff --git a/crates/iterutil/src/exact_size.rs b/crates/iterutil/src/exact_size.rs
new file mode 100644
index 000000000..1385f1c37
--- /dev/null
+++ b/crates/iterutil/src/exact_size.rs
@@ -0,0 +1,25 @@
+/// Similar to `IntoIterator`, but for an iterator with an exact size.
+pub trait IntoExactSizeIterator {
+    type Item;
+    type IntoIter: ExactSizeIterator<Item = Self::Item>;
+
+    /// Converts self into the `ExactSizeIteror`.
+    fn into_iter(self) -> Self::IntoIter;
+}
+
+impl<I> IntoExactSizeIterator for I
+where
+    I: IntoIterator,
+    I::IntoIter: ExactSizeIterator,
+{
+    type Item = I::Item;
+    type IntoIter = I::IntoIter;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.into_iter()
+    }
+}
+
+pub trait FromExactSizeIterator<A>: Sized {
+    fn from_iter<T: IntoExactSizeIterator<Item = A>>(iter: T) -> Self;
+}
diff --git a/crates/iterutil/src/lib.rs b/crates/iterutil/src/lib.rs
new file mode 100644
index 000000000..b44919ad5
--- /dev/null
+++ b/crates/iterutil/src/lib.rs
@@ -0,0 +1 @@
+pub mod exact_size;
diff --git a/crates/rayexec_execution/Cargo.toml b/crates/rayexec_execution/Cargo.toml
index fe854c462..2f05d40f3 100644
--- a/crates/rayexec_execution/Cargo.toml
+++ b/crates/rayexec_execution/Cargo.toml
@@ -10,6 +10,7 @@ rayexec_parser = { path = "../rayexec_parser" }
 rayexec_bullet = { path = "../rayexec_bullet" }
 rayexec_io = { path = "../rayexec_io" }
 fmtutil = { path = "../fmtutil" }
+iterutil = { path = "../iterutil" }
 # stackutil = { path = "../stackutil" } TODO: psm hash issues when compiling to wasm on macos
 
 ahash = { workspace = true }
diff --git a/crates/rayexec_execution/src/arrays/mod.rs b/crates/rayexec_execution/src/arrays/mod.rs
new file mode 100644
index 000000000..8b1378917
--- /dev/null
+++ b/crates/rayexec_execution/src/arrays/mod.rs
@@ -0,0 +1 @@
+
diff --git a/crates/rayexec_execution/src/lib.rs b/crates/rayexec_execution/src/lib.rs
index 36d966315..5c067bc7c 100644
--- a/crates/rayexec_execution/src/lib.rs
+++ b/crates/rayexec_execution/src/lib.rs
@@ -1,3 +1,4 @@
+pub mod arrays;
 pub mod config;
 pub mod database;
 pub mod datasource;