chore: add vendor directory

1 files changed, 162 insertions, 0 deletions

diff --git a/vendor/base64/src/engine/general_purpose/decode_suffix.rs b/vendor/base64/src/engine/general_purpose/decode_suffix.rs
new file mode 100644
index 00000000..02aaf514
--- /dev/null
+++ b/vendor/base64/src/engine/general_purpose/decode_suffix.rs
@@ -0,0 +1,162 @@
+use crate::{
+    engine::{general_purpose::INVALID_VALUE, DecodeMetadata, DecodePaddingMode},
+    DecodeError, DecodeSliceError, PAD_BYTE,
+};
+
+/// Decode the last 0-4 bytes, checking for trailing set bits and padding per the provided
+/// parameters.
+///
+/// Returns the decode metadata representing the total number of bytes decoded, including the ones
+/// indicated as already written by `output_index`.
+pub(crate) fn decode_suffix(
+    input: &[u8],
+    input_index: usize,
+    output: &mut [u8],
+    mut output_index: usize,
+    decode_table: &[u8; 256],
+    decode_allow_trailing_bits: bool,
+    padding_mode: DecodePaddingMode,
+) -> Result<DecodeMetadata, DecodeSliceError> {
+    debug_assert!((input.len() - input_index) <= 4);
+
+    // Decode any leftovers that might not be a complete input chunk of 4 bytes.
+    // Use a u32 as a stack-resident 4 byte buffer.
+    let mut morsels_in_leftover = 0;
+    let mut padding_bytes_count = 0;
+    // offset from input_index
+    let mut first_padding_offset: usize = 0;
+    let mut last_symbol = 0_u8;
+    let mut morsels = [0_u8; 4];
+
+    for (leftover_index, &b) in input[input_index..].iter().enumerate() {
+        // '=' padding
+        if b == PAD_BYTE {
+            // There can be bad padding bytes in a few ways:
+            // 1 - Padding with non-padding characters after it
+            // 2 - Padding after zero or one characters in the current quad (should only
+            //     be after 2 or 3 chars)
+            // 3 - More than two characters of padding. If 3 or 4 padding chars
+            //     are in the same quad, that implies it will be caught by #2.
+            //     If it spreads from one quad to another, it will be an invalid byte
+            //     in the first quad.
+            // 4 - Non-canonical padding -- 1 byte when it should be 2, etc.
+            //     Per config, non-canonical but still functional non- or partially-padded base64
+            //     may be treated as an error condition.
+
+            if leftover_index < 2 {
+                // Check for error #2.
+                // Either the previous byte was padding, in which case we would have already hit
+                // this case, or it wasn't, in which case this is the first such error.
+                debug_assert!(
+                    leftover_index == 0 || (leftover_index == 1 && padding_bytes_count == 0)
+                );
+                let bad_padding_index = input_index + leftover_index;
+                return Err(DecodeError::InvalidByte(bad_padding_index, b).into());
+            }
+
+            if padding_bytes_count == 0 {
+                first_padding_offset = leftover_index;
+            }
+
+            padding_bytes_count += 1;
+            continue;
+        }
+
+        // Check for case #1.
+        // To make '=' handling consistent with the main loop, don't allow
+        // non-suffix '=' in trailing chunk either. Report error as first
+        // erroneous padding.
+        if padding_bytes_count > 0 {
+            return Err(
+                DecodeError::InvalidByte(input_index + first_padding_offset, PAD_BYTE).into(),
+            );
+        }
+
+        last_symbol = b;
+
+        // can use up to 8 * 6 = 48 bits of the u64, if last chunk has no padding.
+        // Pack the leftovers from left to right.
+        let morsel = decode_table[b as usize];
+        if morsel == INVALID_VALUE {
+            return Err(DecodeError::InvalidByte(input_index + leftover_index, b).into());
+        }
+
+        morsels[morsels_in_leftover] = morsel;
+        morsels_in_leftover += 1;
+    }
+
+    // If there was 1 trailing byte, and it was valid, and we got to this point without hitting
+    // an invalid byte, now we can report invalid length
+    if !input.is_empty() && morsels_in_leftover < 2 {
+        return Err(DecodeError::InvalidLength(input_index + morsels_in_leftover).into());
+    }
+
+    match padding_mode {
+        DecodePaddingMode::Indifferent => { /* everything we care about was already checked */ }
+        DecodePaddingMode::RequireCanonical => {
+            // allow empty input
+            if (padding_bytes_count + morsels_in_leftover) % 4 != 0 {
+                return Err(DecodeError::InvalidPadding.into());
+            }
+        }
+        DecodePaddingMode::RequireNone => {
+            if padding_bytes_count > 0 {
+                // check at the end to make sure we let the cases of padding that should be InvalidByte
+                // get hit
+                return Err(DecodeError::InvalidPadding.into());
+            }
+        }
+    }
+
+    // When encoding 1 trailing byte (e.g. 0xFF), 2 base64 bytes ("/w") are needed.
+    // / is the symbol for 63 (0x3F, bottom 6 bits all set) and w is 48 (0x30, top 2 bits
+    // of bottom 6 bits set).
+    // When decoding two symbols back to one trailing byte, any final symbol higher than
+    // w would still decode to the original byte because we only care about the top two
+    // bits in the bottom 6, but would be a non-canonical encoding. So, we calculate a
+    // mask based on how many bits are used for just the canonical encoding, and optionally
+    // error if any other bits are set. In the example of one encoded byte -> 2 symbols,
+    // 2 symbols can technically encode 12 bits, but the last 4 are non-canonical, and
+    // useless since there are no more symbols to provide the necessary 4 additional bits
+    // to finish the second original byte.
+
+    let leftover_bytes_to_append = morsels_in_leftover * 6 / 8;
+    // Put the up to 6 complete bytes as the high bytes.
+    // Gain a couple percent speedup from nudging these ORs to use more ILP with a two-way split.
+    let mut leftover_num = (u32::from(morsels[0]) << 26)
+        | (u32::from(morsels[1]) << 20)
+        | (u32::from(morsels[2]) << 14)
+        | (u32::from(morsels[3]) << 8);
+
+    // if there are bits set outside the bits we care about, last symbol encodes trailing bits that
+    // will not be included in the output
+    let mask = !0_u32 >> (leftover_bytes_to_append * 8);
+    if !decode_allow_trailing_bits && (leftover_num & mask) != 0 {
+        // last morsel is at `morsels_in_leftover` - 1
+        return Err(DecodeError::InvalidLastSymbol(
+            input_index + morsels_in_leftover - 1,
+            last_symbol,
+        )
+        .into());
+    }
+
+    // Strangely, this approach benchmarks better than writing bytes one at a time,
+    // or copy_from_slice into output.
+    for _ in 0..leftover_bytes_to_append {
+        let hi_byte = (leftover_num >> 24) as u8;
+        leftover_num <<= 8;
+        *output
+            .get_mut(output_index)
+            .ok_or(DecodeSliceError::OutputSliceTooSmall)? = hi_byte;
+        output_index += 1;
+    }
+
+    Ok(DecodeMetadata::new(
+        output_index,
+        if padding_bytes_count > 0 {
+            Some(input_index + first_padding_offset)
+        } else {
+            None
+        },
+    ))
+}