introducing alloc feature

Author: stevefan1999-personal

Cargo.toml

@@ -19,5 +19,7 @@ serde = { version = "1", default-features = false, optional = true }
 
 [features]
 default = ["std", "u128"]
-std = ["serde/std"]
+serde = ["alloc"]
+std = ["serde/std", "alloc"]
+alloc = []
 u128 = []

src/adjusted_byte.rs

@@ -1,6 +1,8 @@
 use core::cmp::Ordering;
 
-use alloc::fmt::{self, Display, Formatter};
+use core::fmt::{self, Display, Formatter};
+
+#[cfg(any(feature = "serde", feature = "alloc"))]
 use alloc::string::String;
 
 use crate::{get_bytes, Byte, ByteUnit};
@@ -43,6 +45,7 @@ impl AdjustedByte {
     /// assert_eq!("1555 B", result);
     /// ```
     #[inline]
+    #[cfg(feature = "alloc")]
     pub fn format(&self, fractional_digits: usize) -> String {
         if self.unit == ByteUnit::B {
             format!("{:.0} B", self.value)

src/byte.rs

@@ -4,7 +4,7 @@ use core::str::FromStr;
 #[cfg(feature = "serde")]
 use alloc::string::String;
 
-use alloc::fmt::{self, Display, Formatter};
+use core::fmt::{self, Display, Formatter};
 
 use crate::{
     get_char_from_bytes, read_xib, AdjustedByte, ByteError, ByteUnit, ValueIncorrectError,

src/byte_error.rs

@@ -1,7 +1,7 @@
 #[cfg(feature = "std")]
 use std::error::Error;
 
-use alloc::fmt::{self, Display, Formatter};
+use core::fmt::{self, Display, Formatter};
 
 #[derive(Debug, Clone)]
 /// Error types for parsing values.

src/byte_unit.rs

@@ -4,7 +4,7 @@ use core::str::{from_utf8_unchecked, Bytes, FromStr};
 #[cfg(feature = "serde")]
 use alloc::string::String;
 
-use alloc::fmt::{self, Display, Formatter};
+use core::fmt::{self, Display, Formatter};
 
 use crate::UnitIncorrectError;
 

src/lib.rs

@@ -149,6 +149,7 @@ features = ["serde"]
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+#[cfg(feature = "alloc")]
 #[macro_use]
 extern crate alloc;