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use std::io::Write;↩
use std::mem::size_of;↩
↩
use super::Options;↩
use de::read::BincodeRead;↩
use error::{ErrorKind, Result};↩
↩
pub trait IntEncoding {↩
/// Gets the size (in bytes) that a value would be serialized to.↩
fn u16_size(n: u16) -> u64;↩
/// Gets the size (in bytes) that a value would be serialized to.↩
fn u32_size(n: u32) -> u64;↩
/// Gets the size (in bytes) that a value would be serialized to.↩
fn u64_size(n: u64) -> u64;↩
↩
/// Gets the size (in bytes) that a value would be serialized to.↩
fn i16_size(n: i16) -> u64;↩
/// Gets the size (in bytes) that a value would be serialized to.↩
fn i32_size(n: i32) -> u64;↩
/// Gets the size (in bytes) that a value would be serialized to.↩
fn i64_size(n: i64) -> u64;↩
↩
#[inline(always)]↩
fn len_size(len: usize) -> u64 {↩
Self::u64_size(len as u64)↩
}↩
↩
/// Serializes a sequence length.↩
#[inline(always)]↩
fn serialize_len<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
len: usize,↩
) -> Result<()> {↩
Self::serialize_u64(ser, len as u64)↩
}↩
↩
fn serialize_u16<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
val: u16,↩
) -> Result<()>;↩
↩
fn serialize_u32<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
val: u32,↩
) -> Result<()>;↩
↩
fn serialize_u64<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
val: u64,↩
) -> Result<()>;↩
↩
fn serialize_i16<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
val: i16,↩
) -> Result<()>;↩
↩
fn serialize_i32<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
val: i32,↩
) -> Result<()>;↩
↩
fn serialize_i64<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
val: i64,↩
) -> Result<()>;↩
↩
/// Deserializes a sequence length.↩
#[inline(always)]↩
fn deserialize_len<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<usize> {↩
Self::deserialize_u64(de).and_then(cast_u64_to_usize)↩
}↩
↩
fn deserialize_u16<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<u16>;↩
↩
fn deserialize_u32<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<u32>;↩
↩
fn deserialize_u64<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<u64>;↩
↩
fn deserialize_i16<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<i16>;↩
↩
fn deserialize_i32<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<i32>;↩
↩
fn deserialize_i64<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<i64>;↩
↩
serde_if_integer128! {↩
fn u128_size(v: u128) -> u64;↩
fn i128_size(v: i128) -> u64;↩
fn serialize_u128<W: Write, O: Options>(↩
ser: &mut ::Serializer<W, O>,↩
val: u128,↩
) -> Result<()>;↩
fn deserialize_u128<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u128>;↩
fn serialize_i128<W: Write, O: Options>(↩
ser: &mut ::Serializer<W, O>,↩
val: i128,↩
) -> Result<()>;↩
fn deserialize_i128<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i128>;↩
}↩
}↩
↩
/// Fixed-size integer encoding.↩
///↩
/// * Fixed size integers are encoded directly↩
/// * Enum discriminants are encoded as u32↩
/// * Lengths and usize are encoded as u64↩
#[derive(Copy, Clone)]↩
pub struct FixintEncoding;↩
↩
/// Variable-size integer encoding (excepting [ui]8).↩
///↩
/// Encoding an unsigned integer v (of any type excepting u8) works as follows:↩
///↩
/// 1. If `u < 251`, encode it as a single byte with that value.↩
/// 2. If `251 <= u < 2**16`, encode it as a literal byte 251, followed by a u16 with value `u`.↩
/// 3. If `2**16 <= u < 2**32`, encode it as a literal byte 252, followed by a u32 with value `u`.↩
/// 4. If `2**32 <= u < 2**64`, encode it as a literal byte 253, followed by a u64 with value `u`.↩
/// 5. If `2**64 <= u < 2**128`, encode it as a literal byte 254, followed by a↩
/// u128 with value `u`.↩
///↩
/// Then, for signed integers, we first convert to unsigned using the zigzag algorithm,↩
/// and then encode them as we do for unsigned integers generally. The reason we use this↩
/// algorithm is that it encodes those values which are close to zero in less bytes; the↩
/// obvious algorithm, where we encode the cast values, gives a very large encoding for all↩
/// negative values.↩
///↩
/// The zigzag algorithm is defined as follows:↩
///↩
/// ```ignore↩
/// fn zigzag(v: Signed) -> Unsigned {↩
/// match v {↩
/// 0 => 0,↩
/// v if v < 0 => |v| * 2 - 1↩
/// v if v > 0 => v * 2↩
/// }↩
/// }↩
/// ```↩
///↩
/// And works such that:↩
///↩
/// ```ignore↩
/// assert_eq!(zigzag(0), 0);↩
/// assert_eq!(zigzag(-1), 1);↩
/// assert_eq!(zigzag(1), 2);↩
/// assert_eq!(zigzag(-2), 3);↩
/// assert_eq!(zigzag(2), 4);↩
/// assert_eq!(zigzag(i64::min_value()), u64::max_value());↩
/// ```↩
///↩
/// Note that u256 and the like are unsupported by this format; if and when they are added to the↩
/// language, they may be supported via the extension point given by the 255 byte.↩
#[derive(Copy, Clone)]↩
pub struct VarintEncoding;↩
↩
const SINGLE_BYTE_MAX: u8 = 250;↩
const U16_BYTE: u8 = 251;↩
const U32_BYTE: u8 = 252;↩
const U64_BYTE: u8 = 253;↩
const U128_BYTE: u8 = 254;↩
const DESERIALIZE_EXTENSION_POINT_ERR: &str = r#"↩
Byte 255 is treated as an extension point; it should not be encoding anything.↩
Do you have a mismatched bincode version or configuration?↩
"#;↩
↩
impl VarintEncoding {↩
fn varint_size(n: u64) -> u64 {↩
if n <= SINGLE_BYTE_MAX as u64 {↩
1↩
} else if n <= u16::max_value() as u64 {↩
(1 + size_of::<u16>()) as u64↩
} else if n <= u32::max_value() as u64 {↩
(1 + size_of::<u32>()) as u64↩
} else {↩
(1 + size_of::<u64>()) as u64↩
}↩
}↩
↩
#[inline(always)]↩
fn zigzag_encode(n: i64) -> u64 {↩
if n < 0 {↩
// let's avoid the edge case of i64::min_value()↩
// !n is equal to `-n - 1`, so this is:↩
// !n * 2 + 1 = 2(-n - 1) + 1 = -2n - 2 + 1 = -2n - 1↩
!(n as u64) * 2 + 1↩
} else {↩
(n as u64) * 2↩
}↩
}↩
↩
#[inline(always)]↩
fn zigzag_decode(n: u64) -> i64 {↩
if n % 2 == 0 {↩
// positive number↩
(n / 2) as i64↩
} else {↩
// negative number↩
// !m * 2 + 1 = n↩
// !m * 2 = n - 1↩
// !m = (n - 1) / 2↩
// m = !((n - 1) / 2)↩
// since we have n is odd, we have floor(n / 2) = floor((n - 1) / 2)↩
!(n / 2) as i64↩
}↩
}↩
↩
fn serialize_varint<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
n: u64,↩
) -> Result<()> {↩
if n <= SINGLE_BYTE_MAX as u64 {↩
ser.serialize_byte(n as u8)↩
} else if n <= u16::max_value() as u64 {↩
ser.serialize_byte(U16_BYTE)?;↩
ser.serialize_literal_u16(n as u16)↩
} else if n <= u32::max_value() as u64 {↩
ser.serialize_byte(U32_BYTE)?;↩
ser.serialize_literal_u32(n as u32)↩
} else {↩
ser.serialize_byte(U64_BYTE)?;↩
ser.serialize_literal_u64(n as u64)↩
}↩
}↩
↩
fn deserialize_varint<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<u64> {↩
#[allow(ellipsis_inclusive_range_patterns)]↩
match de.deserialize_byte()? {↩
byte @ 0...SINGLE_BYTE_MAX => Ok(byte as u64),↩
U16_BYTE => Ok(de.deserialize_literal_u16()? as u64),↩
U32_BYTE => Ok(de.deserialize_literal_u32()? as u64),↩
U64_BYTE => de.deserialize_literal_u64(),↩
U128_BYTE => Err(Box::new(ErrorKind::Custom(↩
"Invalid value (u128 range): you may have a version or configuration disagreement?"↩
.to_string(),↩
))),↩
_ => Err(Box::new(ErrorKind::Custom(↩
DESERIALIZE_EXTENSION_POINT_ERR.to_string(),↩
))),↩
}↩
}↩
↩
serde_if_integer128! {↩
// see zigzag_encode and zigzag_decode for implementation comments↩
#[inline(always)]↩
fn zigzag128_encode(n: i128) -> u128 {↩
if n < 0 {↩
!(n as u128) * 2 + 1↩
} else {↩
(n as u128) * 2↩
}↩
}↩
#[inline(always)]↩
fn zigzag128_decode(n: u128) -> i128 {↩
if n % 2 == 0 {↩
(n / 2) as i128↩
} else {↩
!(n / 2) as i128↩
}↩
}↩
↩
fn varint128_size(n: u128) -> u64 {↩
if n <= SINGLE_BYTE_MAX as u128 {↩
1↩
} else if n <= u16::max_value() as u128 {↩
(1 + size_of::<u16>()) as u64↩
} else if n <= u32::max_value() as u128 {↩
(1 + size_of::<u32>()) as u64↩
} else if n <= u64::max_value() as u128 {↩
(1 + size_of::<u64>()) as u64↩
} else {↩
(1 + size_of::<u128>()) as u64↩
}↩
}↩
↩
fn serialize_varint128<W: Write, O: Options>(↩
ser: &mut ::ser::Serializer<W, O>,↩
n: u128,↩
) -> Result<()> {↩
if n <= SINGLE_BYTE_MAX as u128 {↩
ser.serialize_byte(n as u8)↩
} else if n <= u16::max_value() as u128 {↩
ser.serialize_byte(U16_BYTE)?;↩
ser.serialize_literal_u16(n as u16)↩
} else if n <= u32::max_value() as u128 {↩
ser.serialize_byte(U32_BYTE)?;↩
ser.serialize_literal_u32(n as u32)↩
} else if n <= u64::max_value() as u128 {↩
ser.serialize_byte(U64_BYTE)?;↩
ser.serialize_literal_u64(n as u64)↩
} else {↩
ser.serialize_byte(U128_BYTE)?;↩
ser.serialize_literal_u128(n)↩
}↩
}↩
↩
fn deserialize_varint128<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::de::Deserializer<R, O>,↩
) -> Result<u128> {↩
#[allow(ellipsis_inclusive_range_patterns)]↩
match de.deserialize_byte()? {↩
byte @ 0...SINGLE_BYTE_MAX => Ok(byte as u128),↩
U16_BYTE => Ok(de.deserialize_literal_u16()? as u128),↩
U32_BYTE => Ok(de.deserialize_literal_u32()? as u128),↩
U64_BYTE => Ok(de.deserialize_literal_u64()? as u128),↩
U128_BYTE => de.deserialize_literal_u128(),↩
_ => Err(Box::new(ErrorKind::Custom(DESERIALIZE_EXTENSION_POINT_ERR.to_string()))),↩
}↩
}↩
}↩
}↩
↩
impl IntEncoding for FixintEncoding {↩
#[inline(always)]↩
fn u16_size(_: u16) -> u64 {↩
size_of::<u16>() as u64↩
}↩
#[inline(always)]↩
fn u32_size(_: u32) -> u64 {↩
size_of::<u32>() as u64↩
}↩
#[inline(always)]↩
fn u64_size(_: u64) -> u64 {↩
size_of::<u64>() as u64↩
}↩
↩
#[inline(always)]↩
fn i16_size(_: i16) -> u64 {↩
size_of::<i16>() as u64↩
}↩
#[inline(always)]↩
fn i32_size(_: i32) -> u64 {↩
size_of::<i32>() as u64↩
}↩
#[inline(always)]↩
fn i64_size(_: i64) -> u64 {↩
size_of::<i64>() as u64↩
}↩
↩
#[inline(always)]↩
fn serialize_u16<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: u16) -> Result<()> {↩
ser.serialize_literal_u16(val)↩
}↩
#[inline(always)]↩
fn serialize_u32<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: u32) -> Result<()> {↩
ser.serialize_literal_u32(val)↩
}↩
#[inline(always)]↩
fn serialize_u64<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: u64) -> Result<()> {↩
ser.serialize_literal_u64(val)↩
}↩
↩
#[inline(always)]↩
fn serialize_i16<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: i16) -> Result<()> {↩
ser.serialize_literal_u16(val as u16)↩
}↩
#[inline(always)]↩
fn serialize_i32<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: i32) -> Result<()> {↩
ser.serialize_literal_u32(val as u32)↩
}↩
#[inline(always)]↩
fn serialize_i64<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: i64) -> Result<()> {↩
ser.serialize_literal_u64(val as u64)↩
}↩
↩
#[inline(always)]↩
fn deserialize_u16<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u16> {↩
de.deserialize_literal_u16()↩
}↩
#[inline(always)]↩
fn deserialize_u32<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u32> {↩
de.deserialize_literal_u32()↩
}↩
#[inline(always)]↩
fn deserialize_u64<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u64> {↩
de.deserialize_literal_u64()↩
}↩
↩
#[inline(always)]↩
fn deserialize_i16<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i16> {↩
Ok(de.deserialize_literal_u16()? as i16)↩
}↩
#[inline(always)]↩
fn deserialize_i32<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i32> {↩
Ok(de.deserialize_literal_u32()? as i32)↩
}↩
#[inline(always)]↩
fn deserialize_i64<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i64> {↩
Ok(de.deserialize_literal_u64()? as i64)↩
}↩
↩
serde_if_integer128! {↩
#[inline(always)]↩
fn u128_size(_: u128) -> u64{↩
size_of::<u128>() as u64↩
}↩
#[inline(always)]↩
fn i128_size(_: i128) -> u64{↩
size_of::<i128>() as u64↩
}↩
↩
#[inline(always)]↩
fn serialize_u128<W: Write, O: Options>(↩
ser: &mut ::Serializer<W, O>,↩
val: u128,↩
) -> Result<()> {↩
ser.serialize_literal_u128(val)↩
}↩
#[inline(always)]↩
fn serialize_i128<W: Write, O: Options>(↩
ser: &mut ::Serializer<W, O>,↩
val: i128,↩
) -> Result<()> {↩
ser.serialize_literal_u128(val as u128)↩
}↩
#[inline(always)]↩
fn deserialize_u128<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u128> {↩
de.deserialize_literal_u128()↩
}↩
#[inline(always)]↩
fn deserialize_i128<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i128> {↩
Ok(de.deserialize_literal_u128()? as i128)↩
}↩
}↩
}↩
↩
impl IntEncoding for VarintEncoding {↩
#[inline(always)]↩
fn u16_size(n: u16) -> u64 {↩
Self::varint_size(n as u64)↩
}↩
#[inline(always)]↩
fn u32_size(n: u32) -> u64 {↩
Self::varint_size(n as u64)↩
}↩
#[inline(always)]↩
fn u64_size(n: u64) -> u64 {↩
Self::varint_size(n)↩
}↩
↩
#[inline(always)]↩
fn i16_size(n: i16) -> u64 {↩
Self::varint_size(Self::zigzag_encode(n as i64))↩
}↩
#[inline(always)]↩
fn i32_size(n: i32) -> u64 {↩
Self::varint_size(Self::zigzag_encode(n as i64))↩
}↩
#[inline(always)]↩
fn i64_size(n: i64) -> u64 {↩
Self::varint_size(Self::zigzag_encode(n))↩
}↩
↩
#[inline(always)]↩
fn serialize_u16<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: u16) -> Result<()> {↩
Self::serialize_varint(ser, val as u64)↩
}↩
#[inline(always)]↩
fn serialize_u32<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: u32) -> Result<()> {↩
Self::serialize_varint(ser, val as u64)↩
}↩
#[inline(always)]↩
fn serialize_u64<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: u64) -> Result<()> {↩
Self::serialize_varint(ser, val)↩
}↩
↩
#[inline(always)]↩
fn serialize_i16<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: i16) -> Result<()> {↩
Self::serialize_varint(ser, Self::zigzag_encode(val as i64))↩
}↩
#[inline(always)]↩
fn serialize_i32<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: i32) -> Result<()> {↩
Self::serialize_varint(ser, Self::zigzag_encode(val as i64))↩
}↩
#[inline(always)]↩
fn serialize_i64<W: Write, O: Options>(ser: &mut ::Serializer<W, O>, val: i64) -> Result<()> {↩
Self::serialize_varint(ser, Self::zigzag_encode(val))↩
}↩
↩
#[inline(always)]↩
fn deserialize_u16<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u16> {↩
Self::deserialize_varint(de).and_then(cast_u64_to_u16)↩
}↩
#[inline(always)]↩
fn deserialize_u32<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u32> {↩
Self::deserialize_varint(de).and_then(cast_u64_to_u32)↩
}↩
#[inline(always)]↩
fn deserialize_u64<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u64> {↩
Self::deserialize_varint(de)↩
}↩
↩
#[inline(always)]↩
fn deserialize_i16<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i16> {↩
Self::deserialize_varint(de)↩
.map(Self::zigzag_decode)↩
.and_then(cast_i64_to_i16)↩
}↩
#[inline(always)]↩
fn deserialize_i32<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i32> {↩
Self::deserialize_varint(de)↩
.map(Self::zigzag_decode)↩
.and_then(cast_i64_to_i32)↩
}↩
#[inline(always)]↩
fn deserialize_i64<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i64> {↩
Self::deserialize_varint(de).map(Self::zigzag_decode)↩
}↩
↩
serde_if_integer128! {↩
#[inline(always)]↩
fn u128_size(n: u128) -> u64 {↩
Self::varint128_size(n)↩
}↩
#[inline(always)]↩
fn i128_size(n: i128) -> u64 {↩
Self::varint128_size(Self::zigzag128_encode(n))↩
}↩
#[inline(always)]↩
fn serialize_u128<W: Write, O: Options>(↩
ser: &mut ::Serializer<W, O>,↩
val: u128,↩
) -> Result<()> {↩
Self::serialize_varint128(ser, val)↩
}↩
#[inline(always)]↩
fn serialize_i128<W: Write, O: Options>(↩
ser: &mut ::Serializer<W, O>,↩
val: i128,↩
) -> Result<()> {↩
Self::serialize_varint128(ser, Self::zigzag128_encode(val))↩
}↩
#[inline(always)]↩
fn deserialize_u128<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<u128> {↩
Self::deserialize_varint128(de)↩
}↩
#[inline(always)]↩
fn deserialize_i128<'de, R: BincodeRead<'de>, O: Options>(↩
de: &mut ::Deserializer<R, O>,↩
) -> Result<i128> {↩
Self::deserialize_varint128(de).map(Self::zigzag128_decode)↩
}↩
}↩
}↩
↩
fn cast_u64_to_usize(n: u64) -> Result<usize> {↩
if n <= usize::max_value() as u64 {↩
Ok(n as usize)↩
} else {↩
Err(Box::new(ErrorKind::Custom(format!(↩
"Invalid size {}: sizes must fit in a usize (0 to {})",↩
n,↩
usize::max_value()↩
))))↩
}↩
}↩
fn cast_u64_to_u32(n: u64) -> Result<u32> {↩
if n <= u32::max_value() as u64 {↩
Ok(n as u32)↩
} else {↩
Err(Box::new(ErrorKind::Custom(format!(↩
"Invalid u32 {}: you may have a version disagreement?",↩
n,↩
))))↩
}↩
}↩
fn cast_u64_to_u16(n: u64) -> Result<u16> {↩
if n <= u16::max_value() as u64 {↩
Ok(n as u16)↩
} else {↩
Err(Box::new(ErrorKind::Custom(format!(↩
"Invalid u16 {}: you may have a version disagreement?",↩
n,↩
))))↩
}↩
}↩
↩
fn cast_i64_to_i32(n: i64) -> Result<i32> {↩
if n <= i32::max_value() as i64 && n >= i32::min_value() as i64 {↩
Ok(n as i32)↩
} else {↩
Err(Box::new(ErrorKind::Custom(format!(↩
"Invalid i32 {}: you may have a version disagreement?",↩
n,↩
))))↩
}↩
}↩
↩
fn cast_i64_to_i16(n: i64) -> Result<i16> {↩
if n <= i16::max_value() as i64 && n >= i16::min_value() as i64 {↩
Ok(n as i16)↩
} else {↩
Err(Box::new(ErrorKind::Custom(format!(↩
"Invalid i16 {}: you may have a version disagreement?",↩
n,↩
))))↩
}↩
}↩
↩
#[cfg(test)]↩
mod test {↩
use super::VarintEncoding;↩
↩
#[test]↩
fn test_zigzag_encode() {↩
let zigzag = VarintEncoding::zigzag_encode;↩
↩
assert_eq!(zigzag(0), 0);↩
for x in 1..512 {↩
assert_eq!(zigzag(x), (x as u64) * 2);↩
assert_eq!(zigzag(-x), (x as u64) * 2 - 1);↩
}↩
}↩
↩
#[test]↩
fn test_zigzag_decode() {↩
// zigzag'↩
let zigzagp = VarintEncoding::zigzag_decode;↩
for x in (0..512).map(|x| x * 2) {↩
assert_eq!(zigzagp(x), x as i64 / 2);↩
assert_eq!(zigzagp(x + 1), -(x as i64) / 2 - 1);↩
}↩
}↩
↩
#[test]↩
fn test_zigzag_edge_cases() {↩
let (zigzag, zigzagp) = (VarintEncoding::zigzag_encode, VarintEncoding::zigzag_decode);↩
↩
assert_eq!(zigzag(i64::max_value()), u64::max_value() - 1);↩
assert_eq!(zigzag(i64::min_value()), u64::max_value());↩
↩
assert_eq!(zigzagp(u64::max_value() - 1), i64::max_value());↩
assert_eq!(zigzagp(u64::max_value()), i64::min_value());↩
}↩
}↩