diff options
Diffstat (limited to 'vendor/bincode/src/config/int.rs')
| -rw-r--r-- | vendor/bincode/src/config/int.rs | 682 |
1 files changed, 682 insertions, 0 deletions
diff --git a/vendor/bincode/src/config/int.rs b/vendor/bincode/src/config/int.rs new file mode 100644 index 000000000..f716d1abd --- /dev/null +++ b/vendor/bincode/src/config/int.rs @@ -0,0 +1,682 @@ +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());
+ }
+}
|