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