Struct VarVecSeqReader 

pub struct VarVecSeqReader<'a, T: Storable, E: Endianness, B: AsRef<[u64]>>
where
    for<'b> BufBitReader<E, MemWordReader<u64, &'b [u64], true>, DefaultReadParams>: BitRead<E, Error = Infallible> + CodesRead<E> + BitSeek<Error = Infallible>,
{ /* private fields */ }

A stateful, sequential reader for an VarVec optimized for forward access.

This reader is created by the seq_reader method. It maintains an internal cursor corresponding to the last-read element’s position, making it highly efficient for sequential or mostly-forward access patterns.

It is a more specialized tool than VarVecReader.

Performance

VarVecSeqReader maintains an internal state of the current decoding position. When a new get request is made, it decides whether to:

1. Decode Forward (Fast Path): If the requested index is at or after the current position and within the same sample block, the reader decodes forward from its last position. This avoids a costly seek operation and is the primary optimization.

2. Seek and Decode (Fallback): If the requested index is far away or requires moving backward, the reader falls back to seeking to the nearest sample point and decoding from there, just like VarVecReader.

Examples

use compressed_intvec::variable::{VarVec, UVarVec};

let data: Vec<u32> = (0..100).collect();
let vec: UVarVec<u32> = VarVec::from_slice(&data)?;

// Create a reader optimized for sequential access
let mut seq_reader = vec.seq_reader();

// Accessing indices in increasing order is very efficient
assert_eq!(seq_reader.get(10)?, Some(10));
assert_eq!(seq_reader.get(15)?, Some(15)); // Decodes forward from index 10
assert_eq!(seq_reader.get(90)?, Some(90)); // Jumps to a new sample

Implementations

impl<'a, T: Storable, E: Endianness, B: AsRef<[u64]>> VarVecSeqReader<'a, T, E, B>

where for<'b> BufBitReader<E, MemWordReader<u64, &'b [u64], true>, DefaultReadParams>: BitRead<E, Error = Infallible> + CodesRead<E> + BitSeek<Error = Infallible>,

pub fn get(&mut self, index: usize) -> Result<Option<T>, VarVecError>

Retrieves the element at index, or None if out of bounds.

This method leverages the reader’s internal state to optimize access, especially for sequential reads.

pub unsafe fn get_unchecked(&mut self, index: usize) -> T

Retrieves the element at index without bounds checking.

Safety

Calling this method with an out-of-bounds index is undefined behavior. The caller must ensure that index < self.intvec.len().

Trait Implementations

impl<T: Storable, E: Endianness, B: AsRef<[u64]>> Debug for VarVecSeqReader<'_, T, E, B>

where for<'b> BufBitReader<E, MemWordReader<u64, &'b [u64], true>, DefaultReadParams>: BitRead<E, Error = Infallible> + CodesRead<E> + BitSeek<Error = Infallible>,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.