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Diffstat (limited to 'vendor/base64/src/engine/naive.rs')
| -rw-r--r-- | vendor/base64/src/engine/naive.rs | 195 |
1 files changed, 0 insertions, 195 deletions
diff --git a/vendor/base64/src/engine/naive.rs b/vendor/base64/src/engine/naive.rs deleted file mode 100644 index af509bfa..00000000 --- a/vendor/base64/src/engine/naive.rs +++ /dev/null @@ -1,195 +0,0 @@ -use crate::{ - alphabet::Alphabet, - engine::{ - general_purpose::{self, decode_table, encode_table}, - Config, DecodeEstimate, DecodeMetadata, DecodePaddingMode, Engine, - }, - DecodeError, DecodeSliceError, -}; -use std::ops::{BitAnd, BitOr, Shl, Shr}; - -/// Comparatively simple implementation that can be used as something to compare against in tests -pub struct Naive { - encode_table: [u8; 64], - decode_table: [u8; 256], - config: NaiveConfig, -} - -impl Naive { - const ENCODE_INPUT_CHUNK_SIZE: usize = 3; - const DECODE_INPUT_CHUNK_SIZE: usize = 4; - - pub const fn new(alphabet: &Alphabet, config: NaiveConfig) -> Self { - Self { - encode_table: encode_table(alphabet), - decode_table: decode_table(alphabet), - config, - } - } - - fn decode_byte_into_u32(&self, offset: usize, byte: u8) -> Result<u32, DecodeError> { - let decoded = self.decode_table[byte as usize]; - - if decoded == general_purpose::INVALID_VALUE { - return Err(DecodeError::InvalidByte(offset, byte)); - } - - Ok(decoded as u32) - } -} - -impl Engine for Naive { - type Config = NaiveConfig; - type DecodeEstimate = NaiveEstimate; - - fn internal_encode(&self, input: &[u8], output: &mut [u8]) -> usize { - // complete chunks first - - const LOW_SIX_BITS: u32 = 0x3F; - - let rem = input.len() % Self::ENCODE_INPUT_CHUNK_SIZE; - // will never underflow - let complete_chunk_len = input.len() - rem; - - let mut input_index = 0_usize; - let mut output_index = 0_usize; - if let Some(last_complete_chunk_index) = - complete_chunk_len.checked_sub(Self::ENCODE_INPUT_CHUNK_SIZE) - { - while input_index <= last_complete_chunk_index { - let chunk = &input[input_index..input_index + Self::ENCODE_INPUT_CHUNK_SIZE]; - - // populate low 24 bits from 3 bytes - let chunk_int: u32 = - (chunk[0] as u32).shl(16) | (chunk[1] as u32).shl(8) | (chunk[2] as u32); - // encode 4x 6-bit output bytes - output[output_index] = self.encode_table[chunk_int.shr(18) as usize]; - output[output_index + 1] = - self.encode_table[chunk_int.shr(12_u8).bitand(LOW_SIX_BITS) as usize]; - output[output_index + 2] = - self.encode_table[chunk_int.shr(6_u8).bitand(LOW_SIX_BITS) as usize]; - output[output_index + 3] = - self.encode_table[chunk_int.bitand(LOW_SIX_BITS) as usize]; - - input_index += Self::ENCODE_INPUT_CHUNK_SIZE; - output_index += 4; - } - } - - // then leftovers - if rem == 2 { - let chunk = &input[input_index..input_index + 2]; - - // high six bits of chunk[0] - output[output_index] = self.encode_table[chunk[0].shr(2) as usize]; - // bottom 2 bits of [0], high 4 bits of [1] - output[output_index + 1] = - self.encode_table[(chunk[0].shl(4_u8).bitor(chunk[1].shr(4_u8)) as u32) - .bitand(LOW_SIX_BITS) as usize]; - // bottom 4 bits of [1], with the 2 bottom bits as zero - output[output_index + 2] = - self.encode_table[(chunk[1].shl(2_u8) as u32).bitand(LOW_SIX_BITS) as usize]; - - output_index += 3; - } else if rem == 1 { - let byte = input[input_index]; - output[output_index] = self.encode_table[byte.shr(2) as usize]; - output[output_index + 1] = - self.encode_table[(byte.shl(4_u8) as u32).bitand(LOW_SIX_BITS) as usize]; - output_index += 2; - } - - output_index - } - - fn internal_decoded_len_estimate(&self, input_len: usize) -> Self::DecodeEstimate { - NaiveEstimate::new(input_len) - } - - fn internal_decode( - &self, - input: &[u8], - output: &mut [u8], - estimate: Self::DecodeEstimate, - ) -> Result<DecodeMetadata, DecodeSliceError> { - let complete_nonterminal_quads_len = general_purpose::decode::complete_quads_len( - input, - estimate.rem, - output.len(), - &self.decode_table, - )?; - - const BOTTOM_BYTE: u32 = 0xFF; - - for (chunk_index, chunk) in input[..complete_nonterminal_quads_len] - .chunks_exact(4) - .enumerate() - { - let input_index = chunk_index * 4; - let output_index = chunk_index * 3; - - let decoded_int: u32 = self.decode_byte_into_u32(input_index, chunk[0])?.shl(18) - | self - .decode_byte_into_u32(input_index + 1, chunk[1])? - .shl(12) - | self.decode_byte_into_u32(input_index + 2, chunk[2])?.shl(6) - | self.decode_byte_into_u32(input_index + 3, chunk[3])?; - - output[output_index] = decoded_int.shr(16_u8).bitand(BOTTOM_BYTE) as u8; - output[output_index + 1] = decoded_int.shr(8_u8).bitand(BOTTOM_BYTE) as u8; - output[output_index + 2] = decoded_int.bitand(BOTTOM_BYTE) as u8; - } - - general_purpose::decode_suffix::decode_suffix( - input, - complete_nonterminal_quads_len, - output, - complete_nonterminal_quads_len / 4 * 3, - &self.decode_table, - self.config.decode_allow_trailing_bits, - self.config.decode_padding_mode, - ) - } - - fn config(&self) -> &Self::Config { - &self.config - } -} - -pub struct NaiveEstimate { - /// remainder from dividing input by `Naive::DECODE_CHUNK_SIZE` - rem: usize, - /// Length of input that is in complete `Naive::DECODE_CHUNK_SIZE`-length chunks - complete_chunk_len: usize, -} - -impl NaiveEstimate { - fn new(input_len: usize) -> Self { - let rem = input_len % Naive::DECODE_INPUT_CHUNK_SIZE; - let complete_chunk_len = input_len - rem; - - Self { - rem, - complete_chunk_len, - } - } -} - -impl DecodeEstimate for NaiveEstimate { - fn decoded_len_estimate(&self) -> usize { - ((self.complete_chunk_len / 4) + ((self.rem > 0) as usize)) * 3 - } -} - -#[derive(Clone, Copy, Debug)] -pub struct NaiveConfig { - pub encode_padding: bool, - pub decode_allow_trailing_bits: bool, - pub decode_padding_mode: DecodePaddingMode, -} - -impl Config for NaiveConfig { - fn encode_padding(&self) -> bool { - self.encode_padding - } -} |