chacha: hide numbered-param interface in guts

rust-random · May 12, 2021 · 2f4bdfc · 2f4bdfc
1 parent eb88236
commit 2f4bdfc
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Showing 2 changed files with 21 additions and 11 deletions.
diff --git a/rand_chacha/src/chacha.rs b/rand_chacha/src/chacha.rs
@@ -18,9 +18,6 @@ use rand_core::{CryptoRng, Error, RngCore, SeedableRng};
 
 #[cfg(feature = "serde1")] use serde::{Serialize, Deserialize, Serializer, Deserializer};
 
-const STREAM_PARAM_NONCE: u32 = 1;
-const STREAM_PARAM_BLOCK: u32 = 0;
-
 // NB. this must remain consistent with some currently hard-coded numbers in this module
 const BUF_BLOCKS: u8 = 4;
 // number of 32-bit words per ChaCha block (fixed by algorithm definition)
@@ -196,7 +193,7 @@ macro_rules! chacha_impl {
             #[inline]
             pub fn get_word_pos(&self) -> u128 {
                 let buf_start_block = {
-                    let buf_end_block = self.rng.core.state.get_stream_param(STREAM_PARAM_BLOCK);
+                    let buf_end_block = self.rng.core.state.get_block_pos();
                     u64::wrapping_sub(buf_end_block, BUF_BLOCKS.into())
                 };
                 let (buf_offset_blocks, block_offset_words) = {
@@ -221,7 +218,7 @@ macro_rules! chacha_impl {
                 self.rng
                     .core
                     .state
-                    .set_stream_param(STREAM_PARAM_BLOCK, block);
+                    .set_block_pos(block);
                 self.rng.generate_and_set((word_offset % u128::from(BLOCK_WORDS)) as usize);
             }
 
@@ -241,7 +238,7 @@ macro_rules! chacha_impl {
                 self.rng
                     .core
                     .state
-                    .set_stream_param(STREAM_PARAM_NONCE, stream);
+                    .set_nonce(stream);
                 if self.rng.index() != 64 {
                     let wp = self.get_word_pos();
                     self.set_word_pos(wp);
@@ -254,7 +251,7 @@ macro_rules! chacha_impl {
                 self.rng
                     .core
                     .state
-                    .get_stream_param(STREAM_PARAM_NONCE)
+                    .get_nonce()
             }
 
             /// Get the seed.

diff --git a/rand_chacha/src/guts.rs b/rand_chacha/src/guts.rs
@@ -21,6 +21,9 @@ const BUFBLOCKS: u64 = 1 << LOG2_BUFBLOCKS;
 pub(crate) const BUFSZ64: u64 = BLOCK64 * BUFBLOCKS;
 pub(crate) const BUFSZ: usize = BUFSZ64 as usize;
 
+const STREAM_PARAM_NONCE: u32 = 1;
+const STREAM_PARAM_BLOCK: u32 = 0;
+
 #[derive(Clone, PartialEq, Eq)]
 pub struct ChaCha {
     pub(crate) b: vec128_storage,
@@ -83,13 +86,23 @@ impl ChaCha {
     }
 
     #[inline(always)]
-    pub fn set_stream_param(&mut self, param: u32, value: u64) {
-        set_stream_param(self, param, value)
+    pub fn set_block_pos(&mut self, value: u64) {
+        set_stream_param(self, STREAM_PARAM_BLOCK, value)
+    }
+
+    #[inline(always)]
+    pub fn get_block_pos(&self) -> u64 {
+        get_stream_param(self, STREAM_PARAM_BLOCK)
+    }
+
+    #[inline(always)]
+    pub fn set_nonce(&mut self, value: u64) {
+        set_stream_param(self, STREAM_PARAM_NONCE, value)
     }
 
     #[inline(always)]
-    pub fn get_stream_param(&self, param: u32) -> u64 {
-        get_stream_param(self, param)
+    pub fn get_nonce(&self) -> u64 {
+        get_stream_param(self, STREAM_PARAM_NONCE)
     }
 
     #[inline(always)]