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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:22:09 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:22:09 +0000 |
commit | 43a97878ce14b72f0981164f87f2e35e14151312 (patch) | |
tree | 620249daf56c0258faa40cbdcf9cfba06de2a846 /third_party/rust/syn/src/bigint.rs | |
parent | Initial commit. (diff) | |
download | firefox-43a97878ce14b72f0981164f87f2e35e14151312.tar.xz firefox-43a97878ce14b72f0981164f87f2e35e14151312.zip |
Adding upstream version 110.0.1.upstream/110.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/syn/src/bigint.rs')
-rw-r--r-- | third_party/rust/syn/src/bigint.rs | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/third_party/rust/syn/src/bigint.rs b/third_party/rust/syn/src/bigint.rs new file mode 100644 index 0000000000..5397d6beee --- /dev/null +++ b/third_party/rust/syn/src/bigint.rs @@ -0,0 +1,66 @@ +use std::ops::{AddAssign, MulAssign}; + +// For implementing base10_digits() accessor on LitInt. +pub struct BigInt { + digits: Vec<u8>, +} + +impl BigInt { + pub fn new() -> Self { + BigInt { digits: Vec::new() } + } + + pub fn to_string(&self) -> String { + let mut repr = String::with_capacity(self.digits.len()); + + let mut has_nonzero = false; + for digit in self.digits.iter().rev() { + has_nonzero |= *digit != 0; + if has_nonzero { + repr.push((*digit + b'0') as char); + } + } + + if repr.is_empty() { + repr.push('0'); + } + + repr + } + + fn reserve_two_digits(&mut self) { + let len = self.digits.len(); + let desired = + len + !self.digits.ends_with(&[0, 0]) as usize + !self.digits.ends_with(&[0]) as usize; + self.digits.resize(desired, 0); + } +} + +impl AddAssign<u8> for BigInt { + // Assumes increment <16. + fn add_assign(&mut self, mut increment: u8) { + self.reserve_two_digits(); + + let mut i = 0; + while increment > 0 { + let sum = self.digits[i] + increment; + self.digits[i] = sum % 10; + increment = sum / 10; + i += 1; + } + } +} + +impl MulAssign<u8> for BigInt { + // Assumes base <=16. + fn mul_assign(&mut self, base: u8) { + self.reserve_two_digits(); + + let mut carry = 0; + for digit in &mut self.digits { + let prod = *digit * base + carry; + *digit = prod % 10; + carry = prod / 10; + } + } +} |