feat(hints): "full word" from cairo_keccak.json

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 #### Upcoming Changes
 
+* Implement hint for `starkware.cairo.common.cairo_keccak.keccak._copy_inputs` as described by whitelist `starknet/security/whitelists/cairo_keccak.json` [#1058](https://github.com/lambdaclass/cairo-rs/pull/1058)
+
+`BuiltinHintProcessor` now supports the following hint:
+
+    ```python
+    %{ ids.full_word = int(ids.n_bytes >= 8) %}
+    ```
+
 * Add missing hint on vrf.json lib [#1052](https://github.com/lambdaclass/cairo-rs/pull/1052):
 
     `BuiltinHintProcessor` now supports the following hint:

cairo_programs/_keccak_alternative_hint.cairo

@@ -113,6 +113,20 @@ func run_cairo_keccak{output_ptr: felt*, range_check_ptr, bitwise_ptr: BitwiseBu
     _prepare_block{keccak_ptr=output_ptr}(inputs=inputs, n_bytes=n_bytes, state=state);
     _block_permutation_cairo_keccak{keccak_ptr=output_ptr}();
 
+    local full_word: felt;
+    %{ ids.full_word = int(ids.n_bytes >= 8) %}
+    assert full_word = 1;
+
+    let n_bytes = 8;
+    local full_word: felt;
+    %{ ids.full_word = int(ids.n_bytes >= 8) %}
+    assert full_word = 1;
+
+    let n_bytes = 7;
+    local full_word: felt;
+    %{ ids.full_word = int(ids.n_bytes >= 8) %}
+    assert full_word = 0;
+
     return ();
 }
 

src/hint_processor/builtin_hint_processor/builtin_hint_processor_definition.rs

@@ -26,7 +26,7 @@ use crate::{
             },
             cairo_keccak::keccak_hints::{
                 block_permutation_v1, block_permutation_v2, cairo_keccak_finalize_v1,
-                cairo_keccak_finalize_v2, compare_bytes_in_word_nondet,
+                cairo_keccak_finalize_v2, cairo_keccak_is_full_word, compare_bytes_in_word_nondet,
                 compare_keccak_full_rate_in_bytes_nondet, keccak_write_args,
             },
             dict_hint_utils::{
@@ -550,6 +550,9 @@ impl HintProcessor for BuiltinHintProcessor {
             hint_code::SHA256_FINALIZE => {
                 sha256_finalize(vm, &hint_data.ids_data, &hint_data.ap_tracking)
             }
+            hint_code::CAIRO_KECCAK_INPUT_IS_FULL_WORD => {
+                cairo_keccak_is_full_word(vm, &hint_data.ids_data, &hint_data.ap_tracking)
+            }
             hint_code::COMPARE_KECCAK_FULL_RATE_IN_BYTES_NONDET => {
                 compare_keccak_full_rate_in_bytes_nondet(
                     vm,

src/hint_processor/builtin_hint_processor/cairo_keccak/keccak_hints.rs

@@ -7,7 +7,8 @@ use crate::{
     felt::Felt252,
     hint_processor::{
         builtin_hint_processor::hint_utils::{
-            get_integer_from_var_name, get_ptr_from_var_name, insert_value_into_ap,
+            get_integer_from_var_name, get_ptr_from_var_name, insert_value_from_var_name,
+            insert_value_into_ap,
         },
         hint_processor_definition::HintReference,
     },
@@ -181,6 +182,24 @@ pub(crate) fn block_permutation_v1(
     Ok(())
 }
 
+/*
+Implements hint:
+    %{
+        ids.full_word = int(ids.n_bytes >= 8)
+    %}
+*/
+pub(crate) fn cairo_keccak_is_full_word(
+    vm: &mut VirtualMachine,
+    ids_data: &HashMap<String, HintReference>,
+    ap_tracking: &ApTracking,
+) -> Result<(), HintError> {
+    let n_bytes = get_integer_from_var_name("n_bytes", vm, ids_data, ap_tracking)?
+        .to_usize()
+        .unwrap_or(8); // Hack: if it doesn't fit `usize` then it's >= 8
+    let full_word = Felt252::from((n_bytes >= 8) as usize);
+    insert_value_from_var_name("full_word", &full_word, vm, ids_data, ap_tracking)
+}
+
 /*
 Implements hint:
     %{
@@ -362,10 +381,30 @@ mod tests {
         vm::vm_core::VirtualMachine,
     };
     use assert_matches::assert_matches;
+    use rstest::*;
 
     #[cfg(target_arch = "wasm32")]
     use wasm_bindgen_test::*;
 
+    #[rstest]
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+    #[case(0, 0)]
+    #[case(1, 0)]
+    #[case(7, 0)]
+    #[case(8, 1)]
+    #[case(16, 1)]
+    #[case(usize::MAX as i128, 1)]
+    #[case(i128::MAX, 1)]
+    fn cairo_keccak_is_full_word(#[case] n_bytes: i128, #[case] full_bytes: usize) {
+        let hint_code = "ids.full_word = int(ids.n_bytes >= 8)";
+        let mut vm = vm_with_range_check!();
+        vm.segments = segments![((1, 1), n_bytes)];
+        vm.run_context.fp = 2;
+        let ids_data = ids_data!["full_word", "n_bytes"];
+        assert_matches!(run_hint!(vm, ids_data, hint_code), Ok(()));
+        check_memory![vm.segments.memory, ((1, 0), full_bytes)];
+    }
+
     #[test]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
     fn keccak_write_args_valid_test() {

src/hint_processor/builtin_hint_processor/hint_code.rs

@@ -769,6 +769,8 @@ output_values = keccak_func(memory.get_range(
     ids.keccak_ptr_start, _keccak_state_size_felts))
 segments.write_arg(ids.output, output_values)"#;
 
+pub const CAIRO_KECCAK_INPUT_IS_FULL_WORD: &str = r#"ids.full_word = int(ids.n_bytes >= 8)"#;
+
 pub const CAIRO_KECCAK_FINALIZE_V1: &str = r#"# Add dummy pairs of input and output.
 _keccak_state_size_felts = int(ids.KECCAK_STATE_SIZE_FELTS)
 _block_size = int(ids.BLOCK_SIZE)