Simplify serde_utils for hex ints

sigp · Sep 28, 2020 · f1e8fa1 · f1e8fa1
1 parent df3bba1
commit f1e8fa1
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Showing 3 changed files with 25 additions and 42 deletions.
diff --git a/consensus/serde_utils/src/bytes_4_hex.rs b/consensus/serde_utils/src/bytes_4_hex.rs
@@ -2,8 +2,9 @@
 //!
 //! E.g., `[0, 1, 2, 3]` serializes as `"0x00010203"`.
 
+use crate::hex::PrefixedHexVisitor;
 use serde::de::Error;
-use serde::{Deserialize, Deserializer, Serializer};
+use serde::{Deserializer, Serializer};
 
 const BYTES_LEN: usize = 4;
 
@@ -21,24 +22,17 @@ pub fn deserialize<'de, D>(deserializer: D) -> Result<[u8; BYTES_LEN], D::Error>
 where
     D: Deserializer<'de>,
 {
-    let s: String = Deserialize::deserialize(deserializer)?;
-    let mut array = [0 as u8; BYTES_LEN];
-
-    let start = s
-        .as_str()
-        .get(2..)
-        .ok_or_else(|| D::Error::custom("string length too small"))?;
-    let decoded: Vec<u8> = hex::decode(&start).map_err(D::Error::custom)?;
+    let decoded = deserializer.deserialize_str(PrefixedHexVisitor)?;
 
     if decoded.len() != BYTES_LEN {
-        return Err(D::Error::custom("Fork length too long"));
+        return Err(D::Error::custom(format!(
+            "expected {} bytes for array, got {}",
+            BYTES_LEN,
+            decoded.len()
+        )));
     }
 
-    for (i, item) in array.iter_mut().enumerate() {
-        if i > decoded.len() {
-            break;
-        }
-        *item = decoded[i];
-    }
+    let mut array = [0; BYTES_LEN];
+    array.copy_from_slice(&decoded);
     Ok(array)
 }
diff --git a/consensus/serde_utils/src/u32_hex.rs b/consensus/serde_utils/src/u32_hex.rs
@@ -2,31 +2,20 @@
 //!
 //! E.g., `0` serializes as `"0x00000000"`.
 
-use serde::de::Error;
-use serde::{Deserialize, Deserializer, Serializer};
+use crate::bytes_4_hex;
+use serde::{Deserializer, Serializer};
 
 pub fn serialize<S>(num: &u32, serializer: S) -> Result<S::Ok, S::Error>
 where
     S: Serializer,
 {
-    let mut hex: String = "0x".to_string();
-    let bytes = num.to_le_bytes();
-    hex.push_str(&hex::encode(&bytes));
-
+    let hex = format!("0x{}", hex::encode(num.to_le_bytes()));
     serializer.serialize_str(&hex)
 }
 
 pub fn deserialize<'de, D>(deserializer: D) -> Result<u32, D::Error>
 where
     D: Deserializer<'de>,
 {
-    let s: String = Deserialize::deserialize(deserializer)?;
-    let start = s
-        .as_str()
-        .get(2..)
-        .ok_or_else(|| D::Error::custom("string length too small"))?;
-
-    u32::from_str_radix(&start, 16)
-        .map_err(D::Error::custom)
-        .map(u32::from_be)
+    bytes_4_hex::deserialize(deserializer).map(u32::from_le_bytes)
 }
diff --git a/consensus/serde_utils/src/u8_hex.rs b/consensus/serde_utils/src/u8_hex.rs
@@ -2,28 +2,28 @@
 //!
 //! E.g., `0` serializes as `"0x00"`.
 
+use crate::hex::PrefixedHexVisitor;
 use serde::de::Error;
-use serde::{Deserialize, Deserializer, Serializer};
+use serde::{Deserializer, Serializer};
 
 pub fn serialize<S>(byte: &u8, serializer: S) -> Result<S::Ok, S::Error>
 where
     S: Serializer,
 {
-    let mut hex: String = "0x".to_string();
-    hex.push_str(&hex::encode(&[*byte]));
-
+    let hex = format!("0x{}", hex::encode([*byte]));
     serializer.serialize_str(&hex)
 }
 
 pub fn deserialize<'de, D>(deserializer: D) -> Result<u8, D::Error>
 where
     D: Deserializer<'de>,
 {
-    let s: String = Deserialize::deserialize(deserializer)?;
-
-    let start = match s.as_str().get(2..) {
-        Some(start) => start,
-        None => return Err(D::Error::custom("string length too small")),
-    };
-    u8::from_str_radix(&start, 16).map_err(D::Error::custom)
+    let bytes = deserializer.deserialize_str(PrefixedHexVisitor)?;
+    if bytes.len() != 1 {
+        return Err(D::Error::custom(format!(
+            "expected 1 byte for u8, got {}",
+            bytes.len()
+        )));
+    }
+    Ok(bytes[0])
 }