Struct DecoderBuilder 

pub struct DecoderBuilder { /* private fields */ }

Builder for an immutable, reusable Decoder.

Defaults use std::thread::available_parallelism as the maximum decoder budget, 4 MiB decoded chunks, 1 MiB positional input pages and compressed grid spacing, decoder_threads + 2 in-flight chunks, strict gzip framing, no output limit or exact-size expectation, and no line counting. The defaults favor throughput; applications with tight memory budgets can reduce the worker budget, decoded chunk size, or in-flight count.

Implementations

impl DecoderBuilder

pub const fn decoder_threads(self, threads: usize) -> Self

Sets the maximum decoder-worker budget.

Individual paths may use fewer active workers when the input exposes less parallelism or when a larger speculative window would reduce throughput through memory pressure.

This also resets the in-flight chunk count to threads + 2. Call DecoderBuilder::in_flight_chunks afterward to override that value.

pub const fn decoded_chunk_size(self, bytes: usize) -> Self

Sets the target decoded chunk size in bytes.

Larger chunks reduce handoff overhead but can increase per-worker and queued memory. The value must be non-zero and fit in zlib’s uInt.

pub const fn input_page_size(self, bytes: usize) -> Self

Sets the positional input page size in bytes.

The value must be non-zero and fit in zlib’s uInt. A streaming cursor retains at least two bytes so format detection can span short reads.

pub const fn compressed_chunk_size(self, bytes: usize) -> Self

Sets the target spacing between speculative chunk starts.

The current estimated-grid decoder requires at least 1 MiB to keep its independently discovered boundaries strongly validated.

pub const fn in_flight_chunks(self, count: usize) -> Self

Sets the maximum number of decoded chunks awaiting consumption.

This bounds reader backpressure and ordered-result buffering at the final handoff. The value must be non-zero.

pub const fn output_limit(self, bytes: Option<u64>) -> Self

Sets or clears the total decoded-output limit in bytes.

On overflow, decoding returns DecodeError::OutputLimitExceeded before emitting bytes beyond the limit. Output already emitted remains visible to the caller.

pub const fn expected_uncompressed_size(self, bytes: Option<u64>) -> Self

Requires exactly bytes of decoded output, or clears the expectation.

Unlike Self::output_limit, this is both an upper and lower bound. An overrun is rejected before the offending chunk is emitted, and an underrun is rejected after the selected container is complete.

pub const fn count_lines(self, enabled: bool) -> Self

Enables or disables counting newline bytes in the decoded output.

The final count is returned through DecodeReport::line_count. When an index is collected by the same operation, every retained checkpoint is also annotated with the number of preceding newlines and the index records the total. This metadata enables crate::IndexedReader::seek_to_line and gztool version 1 export.

Counting is disabled by default. When disabled, output is not scanned and reports and newly built indexes carry no line metadata.

pub const fn format(self, format: Format) -> Self

Selects the container framing explicitly.

The default is Format::Gzip, preserving strict gzip behavior. Select Format::RawDeflate explicitly because an unwrapped stream has no magic bytes and is never safe to guess.

pub const fn auto_detect_format(self) -> Self

Detects gzip or zlib framing from an exact two-byte prefix.

Raw DEFLATE is never auto-detected. An unrecognized prefix produces DecodeError::UnrecognizedFormat.

pub fn build(self) -> Result<Decoder, ConfigError>

Validates the configuration and creates a reusable decoder.

Errors

Returns ConfigError when a size or count violates the constraints documented on its setter.

Trait Implementations

impl Clone for DecoderBuilder

fn clone(&self) -> DecoderBuilder

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DecoderBuilder

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

Formats the value using the given formatter.

impl Default for DecoderBuilder

fn default() -> Self

Returns the “default value” for a type.