Struct Reader 

pub struct Reader<'a, B: Blocks> { /* private fields */ }

A chain opened for reading.

Holding one means the directory has been read, so every chunk after that is a single fetch. That is the whole reason this is a type rather than a function taking a Chain: an enumeration that walks a spilled collection reads the directory once and not once per chunk.

Implementations

impl<'a, B: Blocks> Reader<'a, B>

pub fn open(blocks: &'a B, chain: Chain) -> Result<Reader<'a, B>>

Read the directory, if there is one, and get ready to fetch chunks.

pub const fn len(&self) -> u64

The value’s length in bytes.

pub const fn is_empty(&self) -> bool

Whether the value has no bytes in it, which is not the same as having no chunks.

pub const fn chunks(&self) -> u64

How many chunks the value is in.

pub fn chunk(&self, i: u64) -> Result<&'a [u8]>

Fetch chunk i, which is one read and never a walk.

pub fn range(&self, from: u64, to: u64) -> Pieces<'a, '_, B>

Walk the pieces of from .. to, in order, without touching a chunk the range does not reach.

This is what GETRANGE on a spilled value wants, and what a membership test on a spilled collection wants, and they are the same walk. A range inside one chunk is one fetch whatever the value’s size is.