Class: RZstd::FrameCodec

Inherits:
Object
  • Object
show all
Defined in:
lib/rzstd/frame_codec.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.new(dict: nil, level: DEFAULT_LEVEL) ⇒ Object

Frame-format Zstd codec, optionally dict-bound. Holds a CCtx and DCtx, each behind a Mutex — the whole reason rzstd exists is to avoid allocating ~256 KiB of ZSTD_*Ctx state per call. Hold the codec across many compress/decompress calls to amortise that.

‘level` is set once at construction and baked into the CCtx; changing level means building a new codec (like `dict:`).

Shareable across Ractors via the interior Mutexes. For parallel throughput, give each Ractor its own FrameCodec.

Parameters:

  • dict (Dictionary, String, nil) (defaults to: nil) —

    dictionary bytes or a Dictionary value. Passing a Dictionary reuses its cached id (skips the sha256 digest / ZDICT header parse); a raw String derives the id on the fly.

  • level (Integer) (defaults to: DEFAULT_LEVEL) —

    compression level. Negative values are zstd’s “fast” strategy; positive values are the standard range.



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# File 'lib/rzstd/frame_codec.rb', line 24

def self.new(dict: nil, level: DEFAULT_LEVEL)
  case dict
  when nil
    _native_new(nil, 0, Integer(level))
  when Dictionary
    _native_new(dict.bytes, dict.id, Integer(level))
  when String
    d = Dictionary.new(bytes: dict)
    _native_new(d.bytes, d.id, Integer(level))
  else
    raise TypeError, "expected RZstd::Dictionary, String, or nil; got #{dict.class}"
  end
end

Instance Method Details

#decompress(bytes, max_output_size: nil) ⇒ Object

Bounded single-shot decompression. When ‘max_output_size:` is given, the Rust extension reads the frame’s Frame_Content_Size header, raises MissingContentSizeError if absent, and raises OutputSizeLimitError if the declared size exceeds the limit —all before allocating the output buffer or invoking the decoder. When nil, frames without FCS fall back to a 1 MiB ceiling.



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# File 'lib/rzstd/frame_codec.rb', line 45

def decompress(bytes, max_output_size: nil)
  _native_decompress(bytes, Integer(max_output_size || 0))
end