diff --git a/library/core/src/hash/sip.rs b/library/core/src/hash/sip.rs index 17f2caaa0c083..bbe0a2b4de611 100644 --- a/library/core/src/hash/sip.rs +++ b/library/core/src/hash/sip.rs @@ -209,10 +209,144 @@ impl Hasher { self.state.v3 = self.k1 ^ 0x7465646279746573; self.ntail = 0; } + + // A specialized write function for values with size <= 8. + // + // The hashing of multi-byte integers depends on endianness. E.g.: + // - little-endian: `write_u32(0xDDCCBBAA)` == `write([0xAA, 0xBB, 0xCC, 0xDD])` + // - big-endian: `write_u32(0xDDCCBBAA)` == `write([0xDD, 0xCC, 0xBB, 0xAA])` + // + // This function does the right thing for little-endian hardware. On + // big-endian hardware `x` must be byte-swapped first to give the right + // behaviour. After any byte-swapping, the input must be zero-extended to + // 64-bits. The caller is responsible for the byte-swapping and + // zero-extension. + #[inline] + fn short_write(&mut self, _x: T, x: u64) { + let size = mem::size_of::(); + self.length += size; + + // The original number must be zero-extended, not sign-extended. + debug_assert!(if size < 8 { x >> (8 * size) == 0 } else { true }); + + // The number of bytes needed to fill `self.tail`. + + let needed = 8 - self.ntail; + + // SipHash parses the input stream as 8-byte little-endian integers. + // Inputs are put into `self.tail` until 8 bytes of data have been + // collected, and then that word is processed. + // + // For example, imagine that `self.tail` is 0x0000_00EE_DDCC_BBAA, + // `self.ntail` is 5 (because 5 bytes have been put into `self.tail`), + // and `needed` is therefore 3. + // + // - Scenario 1, `self.write_u8(0xFF)`: we have already zero-extended + // the input to 0x0000_0000_0000_00FF. We now left-shift it five + // bytes, giving 0x0000_FF00_0000_0000. We then bitwise-OR that value + // into `self.tail`, resulting in 0x0000_FFEE_DDCC_BBAA. + // (Zero-extension of the original input is critical in this scenario + // because we don't want the high two bytes of `self.tail` to be + // touched by the bitwise-OR.) `self.tail` is not yet full, so we + // return early, after updating `self.ntail` to 6. + // + // - Scenario 2, `self.write_u32(0xIIHH_GGFF)`: we have already + // zero-extended the input to 0x0000_0000_IIHH_GGFF. We now + // left-shift it five bytes, giving 0xHHGG_FF00_0000_0000. We then + // bitwise-OR that value into `self.tail`, resulting in + // 0xHHGG_FFEE_DDCC_BBAA. `self.tail` is now full, and we can use it + // to update `self.state`. (As mentioned above, this assumes a + // little-endian machine; on a big-endian machine we would have + // byte-swapped 0xIIHH_GGFF in the caller, giving 0xFFGG_HHII, and we + // would then end up bitwise-ORing 0xGGHH_II00_0000_0000 into + // `self.tail`). + // + self.tail |= x << (8 * self.ntail); + if size < needed { + self.ntail += size; + return; + } + + // `self.tail` is full, process it. + + self.state.v3 ^= self.tail; + S::c_rounds(&mut self.state); + self.state.v0 ^= self.tail; + + // Continuing scenario 2: we have one byte left over from the input. We + // set `self.ntail` to 1 and `self.tail` to `0x0000_0000_IIHH_GGFF >> + // 8*3`, which is 0x0000_0000_0000_00II. (Or on a big-endian machine + // the prior byte-swapping would leave us with 0x0000_0000_0000_00FF.) + // + // The `if` is needed to avoid shifting by 64 bits, which Rust + // complains about. + self.ntail = size - needed; + self.tail = if needed < 8 { x >> (8 * needed) } else { 0 }; + } } #[stable(feature = "rust1", since = "1.0.0")] impl super::Hasher for SipHasher { + #[inline] + fn write_u8(&mut self, i: u8) { + self.0.hasher.write_u8(i); + } + + #[inline] + fn write_u16(&mut self, i: u16) { + self.0.hasher.write_u16(i); + } + + #[inline] + fn write_u32(&mut self, i: u32) { + self.0.hasher.write_u32(i); + } + + #[inline] + fn write_u64(&mut self, i: u64) { + self.0.hasher.write_u64(i); + } + + #[inline] + fn write_u128(&mut self, i: u128) { + self.0.hasher.write_u128(i); + } + + #[inline] + fn write_usize(&mut self, i: usize) { + self.0.hasher.write_usize(i); + } + + #[inline] + fn write_i8(&mut self, i: i8) { + self.0.hasher.write_i8(i); + } + + #[inline] + fn write_i16(&mut self, i: i16) { + self.0.hasher.write_i16(i); + } + + #[inline] + fn write_i32(&mut self, i: i32) { + self.0.hasher.write_i32(i); + } + + #[inline] + fn write_i64(&mut self, i: i64) { + self.0.hasher.write_i64(i); + } + + #[inline] + fn write_i128(&mut self, i: i128) { + self.0.hasher.write_i128(i); + } + + #[inline] + fn write_isize(&mut self, i: isize) { + self.0.hasher.write_isize(i); + } + #[inline] fn write(&mut self, msg: &[u8]) { self.0.hasher.write(msg) @@ -231,6 +365,66 @@ impl super::Hasher for SipHasher { #[unstable(feature = "hashmap_internals", issue = "none")] impl super::Hasher for SipHasher13 { + #[inline] + fn write_u8(&mut self, i: u8) { + self.hasher.write_u8(i); + } + + #[inline] + fn write_u16(&mut self, i: u16) { + self.hasher.write_u16(i); + } + + #[inline] + fn write_u32(&mut self, i: u32) { + self.hasher.write_u32(i); + } + + #[inline] + fn write_u64(&mut self, i: u64) { + self.hasher.write_u64(i); + } + + #[inline] + fn write_u128(&mut self, i: u128) { + self.hasher.write_u128(i); + } + + #[inline] + fn write_usize(&mut self, i: usize) { + self.hasher.write_usize(i); + } + + #[inline] + fn write_i8(&mut self, i: i8) { + self.hasher.write_i8(i); + } + + #[inline] + fn write_i16(&mut self, i: i16) { + self.hasher.write_i16(i); + } + + #[inline] + fn write_i32(&mut self, i: i32) { + self.hasher.write_i32(i); + } + + #[inline] + fn write_i64(&mut self, i: i64) { + self.hasher.write_i64(i); + } + + #[inline] + fn write_i128(&mut self, i: i128) { + self.hasher.write_i128(i); + } + + #[inline] + fn write_isize(&mut self, i: isize) { + self.hasher.write_isize(i); + } + #[inline] fn write(&mut self, msg: &[u8]) { self.hasher.write(msg) @@ -248,13 +442,59 @@ impl super::Hasher for SipHasher13 { } impl super::Hasher for Hasher { - // Note: no integer hashing methods (`write_u*`, `write_i*`) are defined - // for this type. We could add them, copy the `short_write` implementation - // in librustc_data_structures/sip128.rs, and add `write_u*`/`write_i*` - // methods to `SipHasher`, `SipHasher13`, and `DefaultHasher`. This would - // greatly speed up integer hashing by those hashers, at the cost of - // slightly slowing down compile speeds on some benchmarks. See #69152 for - // details. + #[inline] + fn write_u8(&mut self, i: u8) { + self.short_write(i, i as u64); + } + + #[inline] + fn write_u16(&mut self, i: u16) { + self.short_write(i, i.to_le() as u64); + } + + #[inline] + fn write_u32(&mut self, i: u32) { + self.short_write(i, i.to_le() as u64); + } + + #[inline] + fn write_u64(&mut self, i: u64) { + self.short_write(i, i.to_le() as u64); + } + + // `write_u128` is currently unimplemented. + + #[inline] + fn write_usize(&mut self, i: usize) { + self.short_write(i, i.to_le() as u64); + } + + fn write_i8(&mut self, i: i8) { + self.short_write(i, i as u8 as u64); + } + + #[inline] + fn write_i16(&mut self, i: i16) { + self.short_write(i, (i as u16).to_le() as u64); + } + + #[inline] + fn write_i32(&mut self, i: i32) { + self.short_write(i, (i as u32).to_le() as u64); + } + + #[inline] + fn write_i64(&mut self, i: i64) { + self.short_write(i, (i as u64).to_le() as u64); + } + + // `write_i128` is currently unimplemented. + + #[inline] + fn write_isize(&mut self, i: isize) { + self.short_write(i, (i as usize).to_le() as u64); + } + #[inline] fn write(&mut self, msg: &[u8]) { let length = msg.len(); diff --git a/library/std/src/hash/random.rs b/library/std/src/hash/random.rs index 8ef45172eac40..39782e1631579 100644 --- a/library/std/src/hash/random.rs +++ b/library/std/src/hash/random.rs @@ -125,8 +125,65 @@ impl Default for DefaultHasher { #[stable(feature = "hashmap_default_hasher", since = "1.13.0")] impl Hasher for DefaultHasher { - // The underlying `SipHasher13` doesn't override the other - // `write_*` methods, so it's ok not to forward them here. + #[inline] + fn write_u8(&mut self, i: u8) { + self.0.write_u8(i); + } + + #[inline] + fn write_u16(&mut self, i: u16) { + self.0.write_u16(i); + } + + #[inline] + fn write_u32(&mut self, i: u32) { + self.0.write_u32(i); + } + + #[inline] + fn write_u64(&mut self, i: u64) { + self.0.write_u64(i); + } + + #[inline] + fn write_u128(&mut self, i: u128) { + self.0.write_u128(i); + } + + #[inline] + fn write_usize(&mut self, i: usize) { + self.0.write_usize(i); + } + + #[inline] + fn write_i8(&mut self, i: i8) { + self.0.write_i8(i); + } + + #[inline] + fn write_i16(&mut self, i: i16) { + self.0.write_i16(i); + } + + #[inline] + fn write_i32(&mut self, i: i32) { + self.0.write_i32(i); + } + + #[inline] + fn write_i64(&mut self, i: i64) { + self.0.write_i64(i); + } + + #[inline] + fn write_i128(&mut self, i: i128) { + self.0.write_i128(i); + } + + #[inline] + fn write_isize(&mut self, i: isize) { + self.0.write_isize(i); + } #[inline] fn write(&mut self, msg: &[u8]) {