Class: Cohere::Transcribe::PyTorchCheckpoint::ZipArchive

Inherits:
Object
  • Object
show all
Defined in:
lib/cohere/transcribe/pytorch_checkpoint.rb

Overview

Minimal ZIP/ZIP64 central-directory reader. Torch stores tensor records without compression, allowing bounded direct reads from multi-GB files.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path) ⇒ ZipArchive

Returns a new instance of ZipArchive.



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# File 'lib/cohere/transcribe/pytorch_checkpoint.rb', line 71

def initialize(path)
  @path = Pathname(path).expand_path
  @entries = read_entries.freeze
end

Instance Attribute Details

#entries ⇒ Object (readonly)

Returns the value of attribute entries.



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# File 'lib/cohere/transcribe/pytorch_checkpoint.rb', line 69

def entries
  @entries
end

#path ⇒ Object (readonly)

Returns the value of attribute path.



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# File 'lib/cohere/transcribe/pytorch_checkpoint.rb', line 69

def path
  @path
end

Instance Method Details

#fetch(name) ⇒ Object 



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# File 'lib/cohere/transcribe/pytorch_checkpoint.rb', line 76

def fetch(name)
  entries.fetch(name)
rescue KeyError
  raise Error, "PyTorch archive #{path} has no entry #{name.inspect}"
end

#read(name, limit: PICKLE_LIMIT) ⇒ Object 



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# File 'lib/cohere/transcribe/pytorch_checkpoint.rb', line 82

def read(name, limit: PICKLE_LIMIT)
  entry = fetch(name)
  raise Error, "PyTorch archive entry #{name.inspect} exceeds the #{limit}-byte size limit" if entry.size > limit
  if entry.compressed_size > limit + ZIP_COMPRESSED_OVERHEAD
    raise Error,
          "PyTorch archive entry #{name.inspect} has an oversized compressed representation"
  end
  if entry.compression_method.zero? && entry.compressed_size != entry.size
    raise Error, "Stored PyTorch archive entry #{name.inspect} has inconsistent sizes"
  end

  compressed = read_range(entry.data_offset, entry.compressed_size)
  payload = case entry.compression_method
            when 0
              compressed
            when 8
              inflate_bounded(compressed, entry, limit)
            else
              raise Error,
                    "PyTorch archive entry #{name.inspect} uses unsupported ZIP method " \
                    "#{entry.compression_method}"
            end
  if payload.bytesize != entry.size
    raise Error,
          "PyTorch archive entry #{name.inspect} decoded to #{payload.bytesize} bytes; expected #{entry.size}"
  end
  raise Error, "PyTorch archive entry #{name.inspect} failed its CRC check" unless Zlib.crc32(payload) == entry.crc32

  payload
rescue Zlib::Error => e
  raise Error, "Cannot inflate PyTorch archive entry #{name.inspect}: #{e.message}"
end