| // Translated from C to Rust. The original C code can be found at |
| // https://github.com/ulfjack/ryu and carries the following license: |
| // |
| // Copyright 2018 Ulf Adams |
| // |
| // The contents of this file may be used under the terms of the Apache License, |
| // Version 2.0. |
| // |
| // (See accompanying file LICENSE-Apache or copy at |
| // http://www.apache.org/licenses/LICENSE-2.0) |
| // |
| // Alternatively, the contents of this file may be used under the terms of |
| // the Boost Software License, Version 1.0. |
| // (See accompanying file LICENSE-Boost or copy at |
| // https://www.boost.org/LICENSE_1_0.txt) |
| // |
| // Unless required by applicable law or agreed to in writing, this software |
| // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| // KIND, either express or implied. |
| |
| use core::ptr; |
| |
| // Returns (lo, hi). |
| #[cfg(not(integer128))] |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub fn umul128(a: u64, b: u64) -> (u64, u64) { |
| let a_lo = a as u32; |
| let a_hi = (a >> 32) as u32; |
| let b_lo = b as u32; |
| let b_hi = (b >> 32) as u32; |
| |
| let b00 = a_lo as u64 * b_lo as u64; |
| let b01 = a_lo as u64 * b_hi as u64; |
| let b10 = a_hi as u64 * b_lo as u64; |
| let b11 = a_hi as u64 * b_hi as u64; |
| |
| let b00_lo = b00 as u32; |
| let b00_hi = (b00 >> 32) as u32; |
| |
| let mid1 = b10 + b00_hi as u64; |
| let mid1_lo = mid1 as u32; |
| let mid1_hi = (mid1 >> 32) as u32; |
| |
| let mid2 = b01 + mid1_lo as u64; |
| let mid2_lo = mid2 as u32; |
| let mid2_hi = (mid2 >> 32) as u32; |
| |
| let p_hi = b11 + mid1_hi as u64 + mid2_hi as u64; |
| let p_lo = ((mid2_lo as u64) << 32) | b00_lo as u64; |
| |
| (p_lo, p_hi) |
| } |
| |
| #[cfg(not(integer128))] |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub fn shiftright128(lo: u64, hi: u64, dist: u32) -> u64 { |
| // We don't need to handle the case dist >= 64 here (see above). |
| debug_assert!(dist > 0); |
| debug_assert!(dist < 64); |
| (hi << (64 - dist)) | (lo >> dist) |
| } |
| |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub fn div5(x: u64) -> u64 { |
| x / 5 |
| } |
| |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub fn div10(x: u64) -> u64 { |
| x / 10 |
| } |
| |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub fn div100(x: u64) -> u64 { |
| x / 100 |
| } |
| |
| #[cfg_attr(feature = "no-panic", inline)] |
| fn pow5_factor(mut value: u64) -> u32 { |
| let mut count = 0u32; |
| loop { |
| debug_assert!(value != 0); |
| let q = div5(value); |
| let r = (value as u32).wrapping_sub(5u32.wrapping_mul(q as u32)); |
| if r != 0 { |
| break; |
| } |
| value = q; |
| count += 1; |
| } |
| count |
| } |
| |
| // Returns true if value is divisible by 5^p. |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub fn multiple_of_power_of_5(value: u64, p: u32) -> bool { |
| // I tried a case distinction on p, but there was no performance difference. |
| pow5_factor(value) >= p |
| } |
| |
| // Returns true if value is divisible by 2^p. |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub fn multiple_of_power_of_2(value: u64, p: u32) -> bool { |
| debug_assert!(value != 0); |
| debug_assert!(p < 64); |
| // __builtin_ctzll doesn't appear to be faster here. |
| (value & ((1u64 << p) - 1)) == 0 |
| } |
| |
| #[cfg(integer128)] |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub fn mul_shift_64(m: u64, mul: &(u64, u64), j: u32) -> u64 { |
| let b0 = m as u128 * mul.0 as u128; |
| let b2 = m as u128 * mul.1 as u128; |
| (((b0 >> 64) + b2) >> (j - 64)) as u64 |
| } |
| |
| #[cfg(integer128)] |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub unsafe fn mul_shift_all_64( |
| m: u64, |
| mul: &(u64, u64), |
| j: u32, |
| vp: *mut u64, |
| vm: *mut u64, |
| mm_shift: u32, |
| ) -> u64 { |
| ptr::write(vp, mul_shift_64(4 * m + 2, mul, j)); |
| ptr::write(vm, mul_shift_64(4 * m - 1 - mm_shift as u64, mul, j)); |
| mul_shift_64(4 * m, mul, j) |
| } |
| |
| #[cfg(not(integer128))] |
| #[cfg_attr(feature = "no-panic", inline)] |
| pub unsafe fn mul_shift_all_64( |
| mut m: u64, |
| mul: &(u64, u64), |
| j: u32, |
| vp: *mut u64, |
| vm: *mut u64, |
| mm_shift: u32, |
| ) -> u64 { |
| m <<= 1; |
| // m is maximum 55 bits |
| let (lo, tmp) = umul128(m, mul.0); |
| let (mut mid, mut hi) = umul128(m, mul.1); |
| mid = mid.wrapping_add(tmp); |
| hi = hi.wrapping_add((mid < tmp) as u64); // overflow into hi |
| |
| let lo2 = lo.wrapping_add(mul.0); |
| let mid2 = mid.wrapping_add(mul.1).wrapping_add((lo2 < lo) as u64); |
| let hi2 = hi.wrapping_add((mid2 < mid) as u64); |
| ptr::write(vp, shiftright128(mid2, hi2, j - 64 - 1)); |
| |
| if mm_shift == 1 { |
| let lo3 = lo.wrapping_sub(mul.0); |
| let mid3 = mid.wrapping_sub(mul.1).wrapping_sub((lo3 > lo) as u64); |
| let hi3 = hi.wrapping_sub((mid3 > mid) as u64); |
| ptr::write(vm, shiftright128(mid3, hi3, j - 64 - 1)); |
| } else { |
| let lo3 = lo + lo; |
| let mid3 = mid.wrapping_add(mid).wrapping_add((lo3 < lo) as u64); |
| let hi3 = hi.wrapping_add(hi).wrapping_add((mid3 < mid) as u64); |
| let lo4 = lo3.wrapping_sub(mul.0); |
| let mid4 = mid3.wrapping_sub(mul.1).wrapping_sub((lo4 > lo3) as u64); |
| let hi4 = hi3.wrapping_sub((mid4 > mid3) as u64); |
| ptr::write(vm, shiftright128(mid4, hi4, j - 64)); |
| } |
| |
| shiftright128(mid, hi, j - 64 - 1) |
| } |