Drop unnecessary byteorder dependency (#603)

Cargo.toml

@@ -21,7 +21,6 @@ all-features = true
 arbitrary = { default-features = false, optional = true, version = "1.0" }
 arrayvec = { default-features = false, version = "0.7" }
 borsh = { default-features = false, optional = true, version = "0.10.0" }
-byteorder = { default-features = false, optional = true, version = "1.0" }
 bytes = { default-features = false, optional = true, version = "1.0" }
 diesel1 = { default-features = false, optional = true, package = "diesel", version = "1.0" }
 diesel2 = { default-features = false, optional = true, package = "diesel", version = "2.1" }
@@ -60,8 +59,8 @@ db-diesel1-mysql = ["diesel1/mysql", "std"]
 db-diesel1-postgres = ["diesel1/postgres", "std"]
 db-diesel2-mysql = ["diesel2/mysql", "std"]
 db-diesel2-postgres = ["diesel2/postgres", "std"]
-db-postgres = ["dep:byteorder", "dep:bytes", "dep:postgres", "std"]
-db-tokio-postgres = ["dep:byteorder", "dep:bytes", "dep:postgres", "std", "dep:tokio-postgres"]
+db-postgres = ["dep:bytes", "dep:postgres", "std"]
+db-tokio-postgres = ["dep:bytes", "dep:postgres", "std", "dep:tokio-postgres"]
 legacy-ops = []
 maths = []
 maths-nopanic = ["maths"]
@@ -80,7 +79,7 @@ serde-str = ["serde-with-str"]
 serde-with-arbitrary-precision = ["serde", "serde_json/arbitrary_precision", "serde_json/std"]
 serde-with-float = ["serde"]
 serde-with-str = ["serde"]
-std = ["arrayvec/std", "borsh?/std", "byteorder?/std", "bytes?/std", "rand?/std", "rkyv?/std", "serde?/std", "serde_json?/std"]
+std = ["arrayvec/std", "borsh?/std", "bytes?/std", "rand?/std", "rkyv?/std", "serde?/std", "serde_json?/std"]
 tokio-pg = ["db-tokio-postgres"] # Backwards compatability
 
 [[bench]]

src/postgres/driver.rs

@@ -1,9 +1,14 @@
 use crate::postgres::common::*;
 use crate::Decimal;
-use byteorder::{BigEndian, ReadBytesExt};
 use bytes::{BufMut, BytesMut};
 use postgres::types::{to_sql_checked, FromSql, IsNull, ToSql, Type};
-use std::io::Cursor;
+use std::io::{Cursor, Read};
+
+fn read_two_bytes(cursor: &mut Cursor<&[u8]>) -> std::io::Result<[u8; 2]> {
+    let mut result = [0; 2];
+    cursor.read_exact(&mut result)?;
+    Ok(result)
+}
 
 impl<'a> FromSql<'a> for Decimal {
     // Decimals are represented as follows:
@@ -61,17 +66,17 @@ impl<'a> FromSql<'a> for Decimal {
 
     fn from_sql(_: &Type, raw: &[u8]) -> Result<Decimal, Box<dyn std::error::Error + 'static + Sync + Send>> {
         let mut raw = Cursor::new(raw);
-        let num_groups = raw.read_u16::<BigEndian>()?;
-        let weight = raw.read_i16::<BigEndian>()?; // 10000^weight
-                                                   // Sign: 0x0000 = positive, 0x4000 = negative, 0xC000 = NaN
-        let sign = raw.read_u16::<BigEndian>()?;
+        let num_groups = u16::from_be_bytes(read_two_bytes(&mut raw)?);
+        let weight = i16::from_be_bytes(read_two_bytes(&mut raw)?); // 10000^weight
+                                                                    // Sign: 0x0000 = positive, 0x4000 = negative, 0xC000 = NaN
+        let sign = u16::from_be_bytes(read_two_bytes(&mut raw)?);
         // Number of digits (in base 10) to print after decimal separator
-        let scale = raw.read_u16::<BigEndian>()?;
+        let scale = u16::from_be_bytes(read_two_bytes(&mut raw)?);
 
         // Read all of the groups
         let mut groups = Vec::new();
         for _ in 0..num_groups as usize {
-            groups.push(raw.read_u16::<BigEndian>()?);
+            groups.push(u16::from_be_bytes(read_two_bytes(&mut raw)?));
         }
 
         Ok(Self::from_postgres(PostgresDecimal {