From acf9d82841f0a117b5f9384fb76775c3c2c4a16e Mon Sep 17 00:00:00 2001
From: Alejandro Cabeza Romero <alex93cabeza@gmail.com>
Date: Wed, 22 Apr 2026 18:25:15 +0200
Subject: [PATCH] Implement FFI types. Add placeholder for native types.

---
 .gitignore                                    |  3 ++
 .../Cargo.lock                                | 16 +++++++
 .../Cargo.toml                                |  7 +++
 .../src/ffi/bytes.rs                          | 38 ++++++++++++++++
 .../src/ffi/mod.rs                            |  7 +++
 .../src/ffi/status.rs                         | 44 +++++++++++++++++++
 .../src/ffi/witness_input.rs                  |  7 +++
 .../src/lib.rs                                |  2 +
 .../src/types/bytes.rs                        |  0
 .../src/types/mod.rs                          |  3 ++
 .../src/types/status.rs                       |  0
 .../src/types/witness_input.rs                |  0
 12 files changed, 127 insertions(+)
 create mode 100644 rust/logos-blockchain-circuits-types/Cargo.lock
 create mode 100644 rust/logos-blockchain-circuits-types/Cargo.toml
 create mode 100644 rust/logos-blockchain-circuits-types/src/ffi/bytes.rs
 create mode 100644 rust/logos-blockchain-circuits-types/src/ffi/mod.rs
 create mode 100644 rust/logos-blockchain-circuits-types/src/ffi/status.rs
 create mode 100644 rust/logos-blockchain-circuits-types/src/ffi/witness_input.rs
 create mode 100644 rust/logos-blockchain-circuits-types/src/lib.rs
 create mode 100644 rust/logos-blockchain-circuits-types/src/types/bytes.rs
 create mode 100644 rust/logos-blockchain-circuits-types/src/types/mod.rs
 create mode 100644 rust/logos-blockchain-circuits-types/src/types/status.rs
 create mode 100644 rust/logos-blockchain-circuits-types/src/types/witness_input.rs

diff --git a/.gitignore b/.gitignore
index 4e1ae71..317abd5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,6 @@ result
 *.r1cs
 **/input.json
 **/*-input.json
+
+# Rust Codebase
+rust/**/target/
diff --git a/rust/logos-blockchain-circuits-types/Cargo.lock b/rust/logos-blockchain-circuits-types/Cargo.lock
new file mode 100644
index 0000000..9f11a54
--- /dev/null
+++ b/rust/logos-blockchain-circuits-types/Cargo.lock
@@ -0,0 +1,16 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "libc"
+version = "0.2.185"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52ff2c0fe9bc6cb6b14a0592c2ff4fa9ceb83eea9db979b0487cd054946a2b8f"
+
+[[package]]
+name = "logos-blockchain-circuits-types"
+version = "0.1.0"
+dependencies = [
+ "libc",
+]
diff --git a/rust/logos-blockchain-circuits-types/Cargo.toml b/rust/logos-blockchain-circuits-types/Cargo.toml
new file mode 100644
index 0000000..081d099
--- /dev/null
+++ b/rust/logos-blockchain-circuits-types/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "logos-blockchain-circuits-types"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+libc = "0.2.185"
diff --git a/rust/logos-blockchain-circuits-types/src/ffi/bytes.rs b/rust/logos-blockchain-circuits-types/src/ffi/bytes.rs
new file mode 100644
index 0000000..ddf3c84
--- /dev/null
+++ b/rust/logos-blockchain-circuits-types/src/ffi/bytes.rs
@@ -0,0 +1,38 @@
+use libc::free;
+
+mod inner {
+    #[repr(C)]
+    pub struct Buffer<T> {
+        pub data: T,
+        pub size: usize,
+    }
+}
+
+pub type Bytes = inner::Buffer<*mut u8>;
+pub type ConstBytes = inner::Buffer<*const u8>;
+
+/// Frees the data buffer inside a [`Bytes`] struct allocated by the C API.
+///
+/// Only the inner data buffer is freed, not the struct itself, since the latter is managed by the
+/// caller.
+///
+/// # Arguments
+///
+/// - `bytes`: A pointer to a [`Bytes`] struct whose data buffer was allocated by the C API and
+/// needs to be freed.
+///
+/// # Safety
+///
+/// Dereferences raw pointers. The caller must ensure that the pointer is valid.
+pub unsafe fn free_bytes(bytes: *mut Bytes) {
+    if bytes.is_null() {
+        return;
+    }
+
+    let bytes = unsafe { &mut *bytes };
+    if !bytes.data.is_null() {
+        unsafe { free(bytes.data as *mut libc::c_void) };
+    }
+    bytes.data = std::ptr::null_mut();
+    bytes.size = 0;
+}
diff --git a/rust/logos-blockchain-circuits-types/src/ffi/mod.rs b/rust/logos-blockchain-circuits-types/src/ffi/mod.rs
new file mode 100644
index 0000000..1ab276d
--- /dev/null
+++ b/rust/logos-blockchain-circuits-types/src/ffi/mod.rs
@@ -0,0 +1,7 @@
+pub mod status;
+pub mod bytes;
+pub mod witness_input;
+
+pub use status::Status;
+pub use bytes::{Bytes, ConstBytes, free_bytes};
+pub use witness_input::WitnessInput;
diff --git a/rust/logos-blockchain-circuits-types/src/ffi/status.rs b/rust/logos-blockchain-circuits-types/src/ffi/status.rs
new file mode 100644
index 0000000..6cb4b68
--- /dev/null
+++ b/rust/logos-blockchain-circuits-types/src/ffi/status.rs
@@ -0,0 +1,44 @@
+use std::cmp::PartialEq;
+
+#[repr(C)]
+#[derive(Debug, PartialEq)]
+pub enum Code {
+    Ok = 0,
+    DynError = 1,
+    InvalidInput = 2,
+    OutOfMemory = 3,
+}
+
+impl Code {
+    pub fn is_ok(&self) -> bool {
+        self == &Code::Ok
+    }
+
+    pub fn is_error(&self) -> bool {
+        !self.is_ok()
+    }
+}
+
+#[repr(C)]
+#[derive(Debug)]
+pub struct Status {
+    pub code: Code,
+    pub message: String,
+}
+
+impl Status {
+    pub fn ok() -> Self {
+        Status {
+            code: Code::Ok,
+            message: String::new(),
+        }
+    }
+
+    pub fn is_ok(&self) -> bool {
+        self.code.is_ok()
+    }
+
+    pub fn is_error(&self) -> bool {
+        self.code.is_error()
+    }
+}
diff --git a/rust/logos-blockchain-circuits-types/src/ffi/witness_input.rs b/rust/logos-blockchain-circuits-types/src/ffi/witness_input.rs
new file mode 100644
index 0000000..d22bd18
--- /dev/null
+++ b/rust/logos-blockchain-circuits-types/src/ffi/witness_input.rs
@@ -0,0 +1,7 @@
+use std::ffi::c_char;
+use crate::ffi::ConstBytes;
+
+pub struct WitnessInput {
+    pub dat: ConstBytes,
+    pub inputs_json: *const c_char,
+}
diff --git a/rust/logos-blockchain-circuits-types/src/lib.rs b/rust/logos-blockchain-circuits-types/src/lib.rs
new file mode 100644
index 0000000..865ec31
--- /dev/null
+++ b/rust/logos-blockchain-circuits-types/src/lib.rs
@@ -0,0 +1,2 @@
+pub mod ffi;
+pub mod types;
diff --git a/rust/logos-blockchain-circuits-types/src/types/bytes.rs b/rust/logos-blockchain-circuits-types/src/types/bytes.rs
new file mode 100644
index 0000000..e69de29
diff --git a/rust/logos-blockchain-circuits-types/src/types/mod.rs b/rust/logos-blockchain-circuits-types/src/types/mod.rs
new file mode 100644
index 0000000..adabe2d
--- /dev/null
+++ b/rust/logos-blockchain-circuits-types/src/types/mod.rs
@@ -0,0 +1,3 @@
+pub mod bytes;
+pub mod status;
+pub mod witness_input;
diff --git a/rust/logos-blockchain-circuits-types/src/types/status.rs b/rust/logos-blockchain-circuits-types/src/types/status.rs
new file mode 100644
index 0000000..e69de29
diff --git a/rust/logos-blockchain-circuits-types/src/types/witness_input.rs b/rust/logos-blockchain-circuits-types/src/types/witness_input.rs
new file mode 100644
index 0000000..e69de29