/rust/registry/src/index.crates.io-6f17d22bba15001f/num-bigint-0.4.6/src/biguint/addition.rs

Source (jump to first uncovered line)
use super::{BigUint, IntDigits};

use crate::big_digit::{self, BigDigit};
use crate::UsizePromotion;

use core::iter::Sum;
use core::ops::{Add, AddAssign};
use num_traits::CheckedAdd;

#[cfg(target_arch = "x86_64")]
use core::arch::x86_64 as arch;

#[cfg(target_arch = "x86")]
use core::arch::x86 as arch;

// Add with carry:
#[cfg(target_arch = "x86_64")]
cfg_64!(
    #[inline]
    fn adc(carry: u8, a: u64, b: u64, out: &mut u64) -> u8 {
        // Safety: There are absolutely no safety concerns with calling `_addcarry_u64`.
        // It's just unsafe for API consistency with other intrinsics.
        unsafe { arch::_addcarry_u64(carry, a, b, out) }
    }
);

#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
cfg_32!(
    #[inline]
    fn adc(carry: u8, a: u32, b: u32, out: &mut u32) -> u8 {
        // Safety: There are absolutely no safety concerns with calling `_addcarry_u32`.
        // It's just unsafe for API consistency with other intrinsics.
        unsafe { arch::_addcarry_u32(carry, a, b, out) }
    }
);

// fallback for environments where we don't have an addcarry intrinsic
// (copied from the standard library's `carrying_add`)
#[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
#[inline]
fn adc(carry: u8, lhs: BigDigit, rhs: BigDigit, out: &mut BigDigit) -> u8 {
    let (a, b) = lhs.overflowing_add(rhs);
    let (c, d) = a.overflowing_add(carry as BigDigit);
    *out = c;
    u8::from(b || d)
}

/// Two argument addition of raw slices, `a += b`, returning the carry.
///
/// This is used when the data `Vec` might need to resize to push a non-zero carry, so we perform
/// the addition first hoping that it will fit.
///
/// The caller _must_ ensure that `a` is at least as long as `b`.
#[inline]
pub(super) fn __add2(a: &mut [BigDigit], b: &[BigDigit]) -> BigDigit {
    debug_assert!(a.len() >= b.len());

    let mut carry = 0;
    let (a_lo, a_hi) = a.split_at_mut(b.len());

    for (a, b) in a_lo.iter_mut().zip(b) {
        carry = adc(carry, *a, *b, a);
    }

    if carry != 0 {
        for a in a_hi {
            carry = adc(carry, *a, 0, a);
            if carry == 0 {
                break;
            }
        }
    }

    carry as BigDigit
}

/// Two argument addition of raw slices:
/// a += b
///
/// The caller _must_ ensure that a is big enough to store the result - typically this means
/// resizing a to max(a.len(), b.len()) + 1, to fit a possible carry.
pub(super) fn add2(a: &mut [BigDigit], b: &[BigDigit]) {
    let carry = __add2(a, b);

    debug_assert!(carry == 0);
}

forward_all_binop_to_val_ref_commutative!(impl Add for BigUint, add);
forward_val_assign!(impl AddAssign for BigUint, add_assign);

impl Add<&BigUint> for BigUint {
    type Output = BigUint;

    fn add(mut self, other: &BigUint) -> BigUint {
        self += other;
        self
    }
}
impl AddAssign<&BigUint> for BigUint {
    #[inline]
    fn add_assign(&mut self, other: &BigUint) {
        let self_len = self.data.len();
        let carry = if self_len < other.data.len() {
            let lo_carry = __add2(&mut self.data[..], &other.data[..self_len]);
            self.data.extend_from_slice(&other.data[self_len..]);
            __add2(&mut self.data[self_len..], &[lo_carry])
        } else {
            __add2(&mut self.data[..], &other.data[..])
        };
        if carry != 0 {
            self.data.push(carry);
        }
    }
}

promote_unsigned_scalars!(impl Add for BigUint, add);
promote_unsigned_scalars_assign!(impl AddAssign for BigUint, add_assign);
forward_all_scalar_binop_to_val_val_commutative!(impl Add<u32> for BigUint, add);
forward_all_scalar_binop_to_val_val_commutative!(impl Add<u64> for BigUint, add);
forward_all_scalar_binop_to_val_val_commutative!(impl Add<u128> for BigUint, add);

impl Add<u32> for BigUint {
    type Output = BigUint;

    #[inline]
    fn add(mut self, other: u32) -> BigUint {
        self += other;
        self
    }
}

impl AddAssign<u32> for BigUint {
    #[inline]
    fn add_assign(&mut self, other: u32) {
        if other != 0 {
            if self.data.is_empty() {
                self.data.push(0);
            }

            let carry = __add2(&mut self.data, &[other as BigDigit]);
            if carry != 0 {
                self.data.push(carry);
            }
        }
    }
}

impl Add<u64> for BigUint {
    type Output = BigUint;

    #[inline]
    fn add(mut self, other: u64) -> BigUint {
        self += other;
        self
    }
}

impl AddAssign<u64> for BigUint {
    cfg_digit!(
        #[inline]
        fn add_assign(&mut self, other: u64) {
            let (hi, lo) = big_digit::from_doublebigdigit(other);
            if hi == 0 {
                *self += lo;
            } else {
                while self.data.len() < 2 {
                    self.data.push(0);
                }

                let carry = __add2(&mut self.data, &[lo, hi]);
                if carry != 0 {
                    self.data.push(carry);
                }
            }
        }

        #[inline]
        fn add_assign(&mut self, other: u64) {
            if other != 0 {
                if self.data.is_empty() {
                    self.data.push(0);
                }

                let carry = __add2(&mut self.data, &[other as BigDigit]);
                if carry != 0 {
                    self.data.push(carry);
                }
            }
        }
    );
}

impl Add<u128> for BigUint {
    type Output = BigUint;

    #[inline]
    fn add(mut self, other: u128) -> BigUint {
        self += other;
        self
    }
}

impl AddAssign<u128> for BigUint {
    cfg_digit!(
        #[inline]
        fn add_assign(&mut self, other: u128) {
            if other <= u128::from(u64::MAX) {
                *self += other as u64
            } else {
                let (a, b, c, d) = super::u32_from_u128(other);
                let carry = if a > 0 {
                    while self.data.len() < 4 {
                        self.data.push(0);
                    }
                    __add2(&mut self.data, &[d, c, b, a])
                } else {
                    debug_assert!(b > 0);
                    while self.data.len() < 3 {
                        self.data.push(0);
                    }
                    __add2(&mut self.data, &[d, c, b])
                };

                if carry != 0 {
                    self.data.push(carry);
                }
            }
        }

        #[inline]
        fn add_assign(&mut self, other: u128) {
            let (hi, lo) = big_digit::from_doublebigdigit(other);
            if hi == 0 {
                *self += lo;
            } else {
                while self.data.len() < 2 {
                    self.data.push(0);
                }

                let carry = __add2(&mut self.data, &[lo, hi]);
                if carry != 0 {
                    self.data.push(carry);
                }
            }
        }
    );
}

impl CheckedAdd for BigUint {
    #[inline]
    fn checked_add(&self, v: &BigUint) -> Option<BigUint> {
        Some(self.add(v))
    }
}

impl_sum_iter_type!(BigUint);

Coverage Report

Created: 2025-02-21 07:11

Line	Count	Source (jump to first uncovered line)
1		use super::{BigUint, IntDigits};
2
3		use crate::big_digit::{self, BigDigit};
4		use crate::UsizePromotion;
5
6		use core::iter::Sum;
7		use core::ops::{Add, AddAssign};
8		use num_traits::CheckedAdd;
9
10		#[cfg(target_arch = "x86_64")]
11		use core::arch::x86_64 as arch;
12
13		#[cfg(target_arch = "x86")]
14		use core::arch::x86 as arch;
15
16		// Add with carry:
17		#[cfg(target_arch = "x86_64")]
18		cfg_64!(
19		#[inline]
20	0	fn adc(carry: u8, a: u64, b: u64, out: &mut u64) -> u8 {
21	0	// Safety: There are absolutely no safety concerns with calling `_addcarry_u64`.
22	0	// It's just unsafe for API consistency with other intrinsics.
23	0	unsafe { arch::_addcarry_u64(carry, a, b, out) }
24	0	}
25		);
26
27		#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
28		cfg_32!(
29		#[inline]
30		fn adc(carry: u8, a: u32, b: u32, out: &mut u32) -> u8 {
31		// Safety: There are absolutely no safety concerns with calling `_addcarry_u32`.
32		// It's just unsafe for API consistency with other intrinsics.
33		unsafe { arch::_addcarry_u32(carry, a, b, out) }
34		}
35		);
36
37		// fallback for environments where we don't have an addcarry intrinsic
38		// (copied from the standard library's `carrying_add`)
39		#[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
40		#[inline]
41		fn adc(carry: u8, lhs: BigDigit, rhs: BigDigit, out: &mut BigDigit) -> u8 {
42		let (a, b) = lhs.overflowing_add(rhs);
43		let (c, d) = a.overflowing_add(carry as BigDigit);
44		*out = c;
45		u8::from(b \|\| d)
46		}
47
48		/// Two argument addition of raw slices, `a += b`, returning the carry.
49		///
50		/// This is used when the data `Vec` might need to resize to push a non-zero carry, so we perform
51		/// the addition first hoping that it will fit.
52		///
53		/// The caller _must_ ensure that `a` is at least as long as `b`.
54		#[inline]
55	0	pub(super) fn __add2(a: &mut [BigDigit], b: &[BigDigit]) -> BigDigit {
56	0	debug_assert!(a.len() >= b.len());
57
58	0	let mut carry = 0;
59	0	let (a_lo, a_hi) = a.split_at_mut(b.len());
60
61	0	for (a, b) in a_lo.iter_mut().zip(b) {
62	0	carry = adc(carry, a, b, a);
63	0	}
64
65	0	if carry != 0 {
66	0	for a in a_hi {
67	0	carry = adc(carry, *a, 0, a);
68	0	if carry == 0 {
69	0	break;
70	0	}
71		}
72	0	}
73
74	0	carry as BigDigit
75	0	}
76
77		/// Two argument addition of raw slices:
78		/// a += b
79		///
80		/// The caller _must_ ensure that a is big enough to store the result - typically this means
81		/// resizing a to max(a.len(), b.len()) + 1, to fit a possible carry.
82	0	pub(super) fn add2(a: &mut [BigDigit], b: &[BigDigit]) {
83	0	let carry = __add2(a, b);
84	0
85	0	debug_assert!(carry == 0);
86	0	}
87
88		forward_all_binop_to_val_ref_commutative!(impl Add for BigUint, add);
89		forward_val_assign!(impl AddAssign for BigUint, add_assign);
90
91		impl Add<&BigUint> for BigUint {
92		type Output = BigUint;
93
94	0	fn add(mut self, other: &BigUint) -> BigUint {
95	0	self += other;
96	0	self
97	0	}
98		}
99		impl AddAssign<&BigUint> for BigUint {
100		#[inline]
101	0	fn add_assign(&mut self, other: &BigUint) {
102	0	let self_len = self.data.len();
103	0	let carry = if self_len < other.data.len() {
104	0	let lo_carry = __add2(&mut self.data[..], &other.data[..self_len]);
105	0	self.data.extend_from_slice(&other.data[self_len..]);
106	0	__add2(&mut self.data[self_len..], &[lo_carry])
107		} else {
108	0	__add2(&mut self.data[..], &other.data[..])
109		};
110	0	if carry != 0 {
111	0	self.data.push(carry);
112	0	}
113	0	}
114		}
115
116		promote_unsigned_scalars!(impl Add for BigUint, add);
117		promote_unsigned_scalars_assign!(impl AddAssign for BigUint, add_assign);
118		forward_all_scalar_binop_to_val_val_commutative!(impl Add<u32> for BigUint, add);
119		forward_all_scalar_binop_to_val_val_commutative!(impl Add<u64> for BigUint, add);
120		forward_all_scalar_binop_to_val_val_commutative!(impl Add<u128> for BigUint, add);
121
122		impl Add<u32> for BigUint {
123		type Output = BigUint;
124
125		#[inline]
126	0	fn add(mut self, other: u32) -> BigUint {
127	0	self += other;
128	0	self
129	0	}
130		}
131
132		impl AddAssign<u32> for BigUint {
133		#[inline]
134	0	fn add_assign(&mut self, other: u32) {
135	0	if other != 0 {
136	0	if self.data.is_empty() {
137	0	self.data.push(0);
138	0	}
139
140	0	let carry = __add2(&mut self.data, &[other as BigDigit]);
141	0	if carry != 0 {
142	0	self.data.push(carry);
143	0	}
144	0	}
145	0	}
146		}
147
148		impl Add<u64> for BigUint {
149		type Output = BigUint;
150
151		#[inline]
152	0	fn add(mut self, other: u64) -> BigUint {
153	0	self += other;
154	0	self
155	0	}
156		}
157
158		impl AddAssign<u64> for BigUint {
159		cfg_digit!(
160		#[inline]
161		fn add_assign(&mut self, other: u64) {
162		let (hi, lo) = big_digit::from_doublebigdigit(other);
163		if hi == 0 {
164		*self += lo;
165		} else {
166		while self.data.len() < 2 {
167		self.data.push(0);
168		}
169
170		let carry = __add2(&mut self.data, &[lo, hi]);
171		if carry != 0 {
172		self.data.push(carry);
173		}
174		}
175		}
176
177		#[inline]
178	0	fn add_assign(&mut self, other: u64) {
179	0	if other != 0 {
180	0	if self.data.is_empty() {
181	0	self.data.push(0);
182	0	}
183
184	0	let carry = __add2(&mut self.data, &[other as BigDigit]);
185	0	if carry != 0 {
186	0	self.data.push(carry);
187	0	}
188	0	}
189	0	}
190		);
191		}
192
193		impl Add<u128> for BigUint {
194		type Output = BigUint;
195
196		#[inline]
197	0	fn add(mut self, other: u128) -> BigUint {
198	0	self += other;
199	0	self
200	0	}
201		}
202
203		impl AddAssign<u128> for BigUint {
204		cfg_digit!(
205		#[inline]
206		fn add_assign(&mut self, other: u128) {
207		if other <= u128::from(u64::MAX) {
208		*self += other as u64
209		} else {
210		let (a, b, c, d) = super::u32_from_u128(other);
211		let carry = if a > 0 {
212		while self.data.len() < 4 {
213		self.data.push(0);
214		}
215		__add2(&mut self.data, &[d, c, b, a])
216		} else {
217		debug_assert!(b > 0);
218		while self.data.len() < 3 {
219		self.data.push(0);
220		}
221		__add2(&mut self.data, &[d, c, b])
222		};
223
224		if carry != 0 {
225		self.data.push(carry);
226		}
227		}
228		}
229
230		#[inline]
231	0	fn add_assign(&mut self, other: u128) {
232	0	let (hi, lo) = big_digit::from_doublebigdigit(other);
233	0	if hi == 0 {
234	0	*self += lo;
235	0	} else {
236	0	while self.data.len() < 2 {
237	0	self.data.push(0);
238	0	}
239
240	0	let carry = __add2(&mut self.data, &[lo, hi]);
241	0	if carry != 0 {
242	0	self.data.push(carry);
243	0	}
244		}
245	0	}
246		);
247		}
248
249		impl CheckedAdd for BigUint {
250		#[inline]
251	0	fn checked_add(&self, v: &BigUint) -> Option<BigUint> {
252	0	Some(self.add(v))
253	0	}
254		}
255
256		impl_sum_iter_type!(BigUint);