Struct StreamChunker 

pub struct StreamChunker<R> { /* private fields */ }

Streaming iterator that yields content-defined chunks from a reader.

StreamChunker is the primary interface for applying FastCDC to data streams in a memory-efficient manner. It reads data incrementally from any Read source and applies content-defined chunking to produce variable-sized chunks suitable for compression, deduplication, and storage.

Design Goals

• Streaming: Process arbitrarily large files without loading entire contents
• Zero-copy (internal): Minimize data copying within the chunker
• Bounded memory: Fixed buffer size regardless of input size
• Deterministic: Same input always produces identical chunk boundaries
• Iterator-based: Idiomatic Rust API that composes with other iterators

Buffering Strategy

The chunker maintains a fixed-size internal buffer to handle the mismatch between read boundaries (determined by the OS/filesystem) and chunk boundaries (determined by content):

• Buffer size: 2 * max_chunk_size (default: ~128 KB)
• Refill trigger: When available data < max_chunk_size
• Shift threshold: When cursor advances beyond buffer midpoint
• EOF handling: Flushes remaining data as final chunk

Buffer Management Example

Initial state (empty buffer):
[__________________________________|__________________________________]
 0                                 cursor                          2*z

After reading (filled to cursor):
[##################################|__________________________________]
 0                                 cursor=filled                   2*z

After consuming one chunk (cursor advances):
[################XXXXXXXXXXXXXXXXXX|__________________________________]
 0              consumed          cursor                           2*z
                (next chunk)       filled

After shift (move unconsumed data to start):
[XXXXXXXXXXXXXXXXXX________________|__________________________________]
 0                cursor           filled                          2*z
 (new position)

Chunk Boundary Guarantees

The chunker guarantees that:

1. Minimum size: Every chunk (except possibly the last) is ≥ min_size
2. Maximum size: Every chunk is ≤ max_size (strictly enforced)
3. Determinism: Given the same input and parameters, chunk boundaries are identical
4. Completeness: All input bytes appear in exactly one chunk (no gaps, no overlaps)

Performance Considerations

• Memory allocation: Each chunk is copied to an owned Vec<u8>. For zero-allocation iteration, consider using StreamChunkerSlice (if available) or process chunks in-place within the iterator.
• I/O pattern: Reads in large blocks (up to max_chunk_size) to minimize syscalls. Works efficiently with buffered readers but not required.
• CPU cost: Gear hash computation is the bottleneck (~500 MB/s). Consider parallel chunking of independent streams if throughput is critical.

Examples

Basic Usage

use hexz_core::algo::dedup::cdc::StreamChunker;
use hexz_core::algo::dedup::dcam::DedupeParams;
use std::fs::File;

let file = File::open("data.bin")?;
let params = DedupeParams::default();
let chunker = StreamChunker::new(file, params);

for chunk_result in chunker {
    let chunk = chunk_result?;
    println!("Chunk: {} bytes", chunk.len());
}

With Compression Pipeline

use hexz_core::algo::dedup::cdc::StreamChunker;
use hexz_core::algo::dedup::dcam::DedupeParams;
use std::fs::File;
use std::collections::HashMap;

let file = File::open("memory.raw")?;
let params = DedupeParams::default();
let chunker = StreamChunker::new(file, params);

let mut dedup_map: HashMap<u64, usize> = HashMap::new();
let mut unique_chunks = Vec::new();

for chunk_result in chunker {
    let chunk = chunk_result?;
    let hash = crc32fast::hash(&chunk) as u64;

    if !dedup_map.contains_key(&hash) {
        let chunk_id = unique_chunks.len();
        dedup_map.insert(hash, chunk_id);
        // Compress and store chunk
        unique_chunks.push(chunk);
    }
}

println!("Stored {} unique chunks", unique_chunks.len());

Custom Parameters

use hexz_core::algo::dedup::cdc::StreamChunker;
use hexz_core::algo::dedup::dcam::DedupeParams;
use std::fs::File;

let file = File::open("disk.raw")?;

// Custom parameters: larger chunks for better compression ratio
let mut params = DedupeParams::default();
params.f = 15; // 32KB average (was 16KB)
params.m = 8192; // 8KB minimum (was 2KB)
params.z = 131072; // 128KB maximum (was 64KB)

let chunker = StreamChunker::new(file, params);

let chunk_sizes: Vec<usize> = chunker
    .map(|res| res.map(|chunk| chunk.len()))
    .collect::<Result<_, _>>()?;

let avg_size: usize = chunk_sizes.iter().sum::<usize>() / chunk_sizes.len();
println!("Average chunk size: {} bytes", avg_size);

Implementations

impl<R: Read> StreamChunker<R>

pub fn new(reader: R, params: DedupeParams) -> Self

Creates a new streaming chunker with the specified deduplication parameters.

This constructor initializes the chunker’s internal buffer and extracts the relevant FastCDC parameters. The chunker is ready to begin iteration immediately after construction; no separate initialization step is required.

Parameters

• reader: Data source implementing Read. This can be:

  • File for reading from disk
  • Cursor<Vec<u8>> for in-memory data
  • BufReader<File> for buffered I/O (redundant but not harmful)
  • Any other Read implementation (network streams, pipes, etc.)

• params: FastCDC parameters controlling chunk size distribution. Key fields:

  • params.f: Fingerprint bits (average chunk size = 2^f)
  • params.m: Minimum chunk size in bytes
  • params.z: Maximum chunk size in bytes
  • params.w: Rolling hash window size (informational, not used here)

Returns

A new StreamChunker ready to yield chunks via iteration. The chunker takes ownership of the reader and will consume it as iteration proceeds.

Memory Allocation

Allocates a buffer of 2 * params.z bytes (or 2 MB, whichever is larger). This is a one-time allocation that persists for the entire stream:

• Default settings (z=64KB): ~128 KB per chunker
• Large chunks (z=128KB): ~256 KB per chunker
• Small chunks (z=16KB): ~2 MB per chunker (due to 2MB minimum)

The 2MB minimum prevents excessive refill operations for small chunk sizes.

Panics

May panic if memory allocation fails (extremely rare on modern systems with virtual memory, but possible in constrained environments). For default parameters this allocates ~128 KB, well within typical stack/heap limits.

Performance Notes

• No I/O in constructor: Data reading is deferred until first next() call
• Deterministic: Given the same input and parameters, produces identical chunks
• Thread-safe (if R is): The chunker itself has no shared state

Examples

Default Parameters

use hexz_core::algo::dedup::cdc::StreamChunker;
use hexz_core::algo::dedup::dcam::DedupeParams;
use std::fs::File;

let file = File::open("data.bin")?;
let chunker = StreamChunker::new(file, DedupeParams::default());
// Chunker is ready to iterate

Custom Parameters

use hexz_core::algo::dedup::cdc::StreamChunker;
use hexz_core::algo::dedup::dcam::DedupeParams;
use std::fs::File;

let file = File::open("disk.raw")?;
let params = DedupeParams {
    f: 15,       // 32KB average
    m: 4096,     // 4KB minimum
    z: 131072,   // 128KB maximum
    w: 48,       // Window size (not used by StreamChunker)
    v: 16,       // Metadata overhead (not used by StreamChunker)
};
let chunker = StreamChunker::new(file, params);

Trait Implementations

impl<R: Read> Iterator for StreamChunker<R>

fn next(&mut self) -> Option<Self::Item>

Yields the next content-defined chunk.

This is the core iterator method that drives the chunking process. Each call performs the following operations:

Algorithm

1. Check for data: If buffer is empty and EOF not reached, refill
2. Handle EOF: If no data available after refill, return None
3. Determine available window: Compute bytes available for chunking
4. Apply FastCDC:
   • If available < min_size: Return all available bytes (last chunk)
   • Else: Run FastCDC on window [cursor..min(cursor+max_size, filled)]
5. Extract chunk: Copy chunk bytes to new Vec<u8>, advance cursor
6. Return: Yield Some(Ok(chunk))

FastCDC Integration

The method delegates to the fastcdc crate’s FastCDC::new() constructor, which implements the normalized chunking algorithm. The returned chunk length respects all size constraints:

• No chunk < min_size (except final chunk)
• No chunk > max_size (strictly enforced)
• Average chunk size ≈ avg_size = 2^f

Chunk Length Determination

The algorithm chooses chunk length as follows:

Condition	Action
available < min_size	Return all available bytes
FastCDC finds cut point	Use FastCDC-determined length
available >= max_size && no cut point	Force cut at max_size
EOF reached && no cut point	Return all remaining bytes
Buffer full && no cut point	Force cut at max_size
Other	Return all available bytes

Returns

• Some(Ok(chunk)) - Next chunk successfully extracted and copied
• Some(Err(e)) - I/O error occurred during refill
• None - Stream exhausted (no more data available)

Errors

Returns Some(Err(e)) if the underlying reader encounters an I/O error during refill. After an error, the iterator should be considered invalid (further calls may panic or return inconsistent results).

Common error causes:

• File read errors (permissions, disk errors)
• Network errors (timeouts, connection reset)
• Interrupted system calls (usually auto-retried)

Chunk Size Guarantees

The returned chunks satisfy these constraints:

• Minimum: ≥ min_size (except possibly the last chunk)
• Maximum: ≤ max_size (always enforced, never violated)
• Average: ≈ avg_size = 2^f (statistical expectation)
• Last chunk: May be smaller than min_size if EOF reached

Memory Allocation

Each chunk is copied to a new Vec<u8>. For zero-copy iteration within the buffer lifetime, consider modifying the API to return slices with appropriate lifetimes (future enhancement).

Examples

use hexz_core::algo::dedup::cdc::StreamChunker;
use hexz_core::algo::dedup::dcam::DedupeParams;
use std::fs::File;

let file = File::open("data.bin")?;
let mut chunker = StreamChunker::new(file, DedupeParams::default());

// First chunk
if let Some(Ok(chunk)) = chunker.next() {
    println!("First chunk: {} bytes", chunk.len());
}

// Iterate remaining chunks
for chunk_result in chunker {
    let chunk = chunk_result?;
    // Process chunk...
}

Performance Characteristics

• Amortized time: O(chunk_size) per chunk (dominated by copying)
• Space: O(chunk_size) allocation per chunk yielded
• Throughput: ~500 MB/s on modern CPUs (bottlenecked by Gear hash)

type Item = Result<Vec<u8>, Error>

The type of the elements being iterated over.

fn next_chunk<const N: usize>( &mut self, ) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk)

Advances the iterator and returns an array containing the next N values.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

fn count(self) -> usize

where Self: Sized,

Consumes the iterator, counting the number of iterations and returning it.

fn last(self) -> Option<Self::Item>

where Self: Sized,

Consumes the iterator, returning the last element.

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator by n elements.

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator.

fn step_by(self, step: usize) -> StepBy<Self>

where Self: Sized,

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence.

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs.

fn intersperse(self, separator: Self::Item) -> Intersperse<Self>

where Self: Sized, Self::Item: Clone,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places a copy of separator between adjacent items of the original iterator.

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>

where Self: Sized, G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places an item generated by separator between adjacent items of the original iterator.

fn map<B, F>(self, f: F) -> Map<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each element.

fn for_each<F>(self, f: F)

where Self: Sized, F: FnMut(Self::Item),

Calls a closure on each element of an iterator.

fn filter<P>(self, predicate: P) -> Filter<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element should be yielded.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>

where Self: Sized,

Creates an iterator which gives the current iteration count as well as the next value.

fn peekable(self) -> Peekable<Self>

where Self: Sized,

Creates an iterator which can use the peek and peek_mut methods to look at the next element of the iterator without consuming it. See their documentation for more information.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate.

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>

where Self: Sized, P: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both yields elements based on a predicate and maps.

fn skip(self, n: usize) -> Skip<Self>

where Self: Sized,

Creates an iterator that skips the first n elements.

fn take(self, n: usize) -> Take<Self>

where Self: Sized,

Creates an iterator that yields the first n elements, or fewer if the underlying iterator ends sooner.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>

where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option<B>,

An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>

where Self: Sized, U: IntoIterator, F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure.

fn flatten(self) -> Flatten<Self>

where Self: Sized, Self::Item: IntoIterator,

Creates an iterator that flattens nested structure.

fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N>

where Self: Sized, F: FnMut(&[Self::Item; N]) -> R,

🔬This is a nightly-only experimental API. (iter_map_windows)

Calls the given function f for each contiguous window of size N over self and returns an iterator over the outputs of f. Like slice::windows(), the windows during mapping overlap as well.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Creates an iterator which ends after the first None.

fn inspect<F>(self, f: F) -> Inspect<Self, F>

where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Iterator.

fn collect<B>(self) -> B

where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection.

fn try_collect<B>( &mut self, ) -> <<Self::Item as Try>::Residual as Residual<B>>::TryType

where Self: Sized, Self::Item: Try, <Self::Item as Try>::Residual: Residual<B>, B: FromIterator<<Self::Item as Try>::Output>,

🔬This is a nightly-only experimental API. (iterator_try_collect)

Fallibly transforms an iterator into a collection, short circuiting if a failure is encountered.

fn collect_into<E>(self, collection: &mut E) -> &mut E

where E: Extend<Self::Item>, Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into)

Collects all the items from an iterator into a collection.

fn partition<B, F>(self, f: F) -> (B, B)

where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it.

fn is_partitioned<P>(self, predicate: P) -> bool

where Self: Sized, P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned)

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false.

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R

where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

fn try_for_each<F, R>(&mut self, f: F) -> R

where Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

fn fold<B, F>(self, init: B, f: F) -> B

where Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result.

fn reduce<F>(self, f: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation.

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType

where Self: Sized, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately.

fn all<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate.

fn any<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate.

fn find<P>(&mut self, predicate: P) -> Option<Self::Item>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate.

fn find_map<B, F>(&mut self, f: F) -> Option<B>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Applies function to the elements of iterator and returns the first non-none result.

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType

where Self: Sized, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find)

Applies function to the elements of iterator and returns the first true result or the first error.

fn position<P>(&mut self, predicate: P) -> Option<usize>

where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index.

fn max(self) -> Option<Self::Item>

where Self: Sized, Self::Item: Ord,

Returns the maximum element of an iterator.

fn min(self) -> Option<Self::Item>

where Self: Sized, Self::Item: Ord,

Returns the minimum element of an iterator.

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function.

fn max_by<F>(self, compare: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function.

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function.

fn min_by<F>(self, compare: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)

where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers.

fn copied<'a, T>(self) -> Copied<Self>

where T: Copy + 'a, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements.

fn cloned<'a, T>(self) -> Cloned<Self>

where T: Clone + 'a, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements.

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks)

Returns an iterator over N elements of the iterator at a time.

fn sum<S>(self) -> S

where Self: Sized, S: Sum<Self::Item>,

Sums the elements of an iterator.

fn product<P>(self) -> P

where Self: Sized, P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements

fn cmp<I>(self, other: I) -> Ordering

where I: IntoIterator<Item = Self::Item>, Self::Item: Ord, Self: Sized,

Lexicographically compares the elements of this Iterator with those of another.

fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn partial_cmp<I>(self, other: I) -> Option<Ordering>

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Lexicographically compares the PartialOrd elements of this Iterator with those of another. The comparison works like short-circuit evaluation, returning a result without comparing the remaining elements. As soon as an order can be determined, the evaluation stops and a result is returned.

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn eq<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are equal to those of another.

fn eq_by<I, F>(self, other: I, eq: F) -> bool

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by)

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

fn ne<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are not equal to those of another.

fn lt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less than those of another.

fn le<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

fn gt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than those of another.

fn ge<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

fn is_sorted(self) -> bool

where Self: Sized, Self::Item: PartialOrd,

Checks if the elements of this iterator are sorted.

fn is_sorted_by<F>(self, compare: F) -> bool

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> bool,

Checks if the elements of this iterator are sorted using the given comparator function.

fn is_sorted_by_key<F, K>(self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> K, K: PartialOrd,

Checks if the elements of this iterator are sorted using the given key extraction function.