diff options
Diffstat (limited to 'vendor/generic-array-0.12.4/src/hex.rs')
-rw-r--r-- | vendor/generic-array-0.12.4/src/hex.rs | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/vendor/generic-array-0.12.4/src/hex.rs b/vendor/generic-array-0.12.4/src/hex.rs new file mode 100644 index 000000000..3ef92b1b9 --- /dev/null +++ b/vendor/generic-array-0.12.4/src/hex.rs @@ -0,0 +1,102 @@ +//! Generic array are commonly used as a return value for hash digests, so +//! it's a good idea to allow to hexlify them easily. This module implements +//! `std::fmt::LowerHex` and `std::fmt::UpperHex` traits. +//! +//! Example: +//! +//! ```rust +//! # #[macro_use] +//! # extern crate generic_array; +//! # extern crate typenum; +//! # fn main() { +//! let array = arr![u8; 10, 20, 30]; +//! assert_eq!(format!("{:x}", array), "0a141e"); +//! # } +//! ``` +//! + +use {ArrayLength, GenericArray}; +use core::cmp::min; +use core::fmt; +use core::ops::Add; +use core::str; +use typenum::*; + +static LOWER_CHARS: &'static [u8] = b"0123456789abcdef"; +static UPPER_CHARS: &'static [u8] = b"0123456789ABCDEF"; + +impl<T: ArrayLength<u8>> fmt::LowerHex for GenericArray<u8, T> +where + T: Add<T>, + <T as Add<T>>::Output: ArrayLength<u8>, +{ + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + let max_digits = f.precision().unwrap_or_else(|| self.len() * 2); + let max_hex = (max_digits >> 1) + (max_digits & 1); + + if T::to_usize() < 1024 { + // For small arrays use a stack allocated + // buffer of 2x number of bytes + let mut res = GenericArray::<u8, Sum<T, T>>::default(); + + for (i, c) in self.iter().take(max_hex).enumerate() { + res[i * 2] = LOWER_CHARS[(c >> 4) as usize]; + res[i * 2 + 1] = LOWER_CHARS[(c & 0xF) as usize]; + } + f.write_str(unsafe { str::from_utf8_unchecked(&res[..max_digits]) })?; + } else { + // For large array use chunks of up to 1024 bytes (2048 hex chars) + let mut buf = [0u8; 2048]; + let mut digits_left = max_digits; + + for chunk in self[..max_hex].chunks(1024) { + for (i, c) in chunk.iter().enumerate() { + buf[i * 2] = LOWER_CHARS[(c >> 4) as usize]; + buf[i * 2 + 1] = LOWER_CHARS[(c & 0xF) as usize]; + } + let n = min(chunk.len() * 2, digits_left); + f.write_str(unsafe { str::from_utf8_unchecked(&buf[..n]) })?; + digits_left -= n; + } + } + Ok(()) + } +} + +impl<T: ArrayLength<u8>> fmt::UpperHex for GenericArray<u8, T> +where + T: Add<T>, + <T as Add<T>>::Output: ArrayLength<u8>, +{ + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + let max_digits = f.precision().unwrap_or_else(|| self.len() * 2); + let max_hex = (max_digits >> 1) + (max_digits & 1); + + if T::to_usize() < 1024 { + // For small arrays use a stack allocated + // buffer of 2x number of bytes + let mut res = GenericArray::<u8, Sum<T, T>>::default(); + + for (i, c) in self.iter().take(max_hex).enumerate() { + res[i * 2] = UPPER_CHARS[(c >> 4) as usize]; + res[i * 2 + 1] = UPPER_CHARS[(c & 0xF) as usize]; + } + f.write_str(unsafe { str::from_utf8_unchecked(&res[..max_digits]) })?; + } else { + // For large array use chunks of up to 1024 bytes (2048 hex chars) + let mut buf = [0u8; 2048]; + let mut digits_left = max_digits; + + for chunk in self[..max_hex].chunks(1024) { + for (i, c) in chunk.iter().enumerate() { + buf[i * 2] = UPPER_CHARS[(c >> 4) as usize]; + buf[i * 2 + 1] = UPPER_CHARS[(c & 0xF) as usize]; + } + let n = min(chunk.len() * 2, digits_left); + f.write_str(unsafe { str::from_utf8_unchecked(&buf[..n]) })?; + digits_left -= n; + } + } + Ok(()) + } +} |