Struct PrefixReader 

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

A reader seeded with the file’s leading bytes: any range inside them is served from memory, the rest goes to inner. The open reads the first crate::v06::FIRST_READ bytes once; a 0x05 open’s header, card and first container prefixes then cost nothing more.

Implementations

impl<R> PrefixReader<R>

where R: RangeReader,

pub fn new(inner: R, prefix: Arc<[u8]>) -> PrefixReader<R>

Seed inner with prefix (its bytes from offset 0).

Trait Implementations

impl<R> RangeReader for PrefixReader<R>

where R: RangeReader,

fn len(&self) -> u64

Total resource length in bytes.

fn read_at(&self, offset: u64, len: u64) -> Result<Vec<u8>, Error>

Read len bytes starting at offset. Implementations should error on an out-of-bounds range rather than truncating.

fn read_many(&self, ranges: &[(u64, u64)]) -> Result<Vec<Vec<u8>>, Error>

Read several (offset, len) ranges, returning each range’s bytes in request order. These ranges are independent, so a reader whose backing store is high-latency but parallelizable (an HTTP client) overrides this to issue the reads concurrently — turning N round trips into ~N/P. The default fetches them sequentially. Any range failing fails the batch.

fn concurrency(&self) -> usize

How many ranges this reader can usefully have in flight at once — the planner’s hint for probe-vs-scan and batch-size decisions (a phone’s serial sync-XHR reader reports 1; the CLI’s threaded HTTP client and the browser’s concurrent-fetch variants report their fan-out). Purely advisory: correctness never depends on it. Defaults to 1 (sequential).

fn is_empty(&self) -> bool

True when the resource is empty.