Crate memcomparable

A memcomparable serialization format.

The memcomparable format allows comparison of two values by using the simple memcmp function.

Usage

// serialize
let key1 = memcomparable::to_vec(&"hello").unwrap();
let key2 = memcomparable::to_vec(&"world").unwrap();
assert!(key1 < key2);

// deserialize
let v1: String = memcomparable::from_slice(&key1).unwrap();
let v2: String = memcomparable::from_slice(&key2).unwrap();
assert_eq!(v1, "hello");
assert_eq!(v2, "world");

Features

• decimal: Enable (de)serialization for Decimal type.
  • Serializer::serialize_decimal
  • Deserializer::deserialize_decimal

Format

The serialization format follows MySQL’s memcomparable format.

Type	Length (bytes)
bool	1
char	4
i8/i16/i32/i64/u8/u16/u32/u64	1/2/4/8
f32/f64	4/8
Decimal	Variable
str/bytes	(L + 7) / 8 x 9
Option<T>	1 + len(T)
&[T]	(1 + len(T)) x L + 1
(T1, T2, ..)	sum(len(Ti))
struct { a: T1, b: T2, .. }	sum(len(Ti))
enum { V1, V2, .. }	1 + len(Vi)

WARN: The format is not guaranteed to be stable in minor version change, e.g. 0.1 -> 0.2.

Structs

Deserializer

A structure that deserializes memcomparable bytes into Rust values.

Serializer

A structure for serializing Rust values into a memcomparable bytes.

Enums

Decimal

An extended decimal number with NaN, -Inf and Inf.

Error

An error that can be produced during (de)serializing.

Functions

from_slice

Deserialize an instance of type T from a memcomparable bytes.

to_vec

Serialize the given data structure as a memcomparable byte vector.

Type Aliases

Result

The result of a serialization or deserialization operation.