Sha256: 3be073d645465fa4e7500cac35e6a94956424ca84a78e26cb286cfab160b6e3c
Contents?: true
Size: 1.72 KB
Versions: 8
Compression:
Stored size: 1.72 KB
Contents
# frozen_string_literal: true
# Sends writes to the given `io` compressed using a `Zlib::Deflate`. Also
# registers data passing through it in a CRC32 checksum calculator. Is made to be completely
# interchangeable with the StoredWriter in terms of interface.
class ZipKit::Streamer::DeflatedWriter
include ZipKit::WriteShovel
# The amount of bytes we will buffer before computing the intermediate
# CRC32 checksums. Benchmarks show that the optimum is 64KB (see
# `bench/buffered_crc32_bench.rb), if that is exceeded Zlib is going
# to perform internal CRC combine calls which will make the speed go down again.
CRC32_BUFFER_SIZE = 64 * 1024
def initialize(io)
@compressed_io = io
@deflater = ::Zlib::Deflate.new(Zlib::DEFAULT_COMPRESSION, -::Zlib::MAX_WBITS)
@crc = ZipKit::StreamCRC32.new
@crc_buf = ZipKit::WriteBuffer.new(@crc, CRC32_BUFFER_SIZE)
end
# Writes the given data into the deflater, and flushes the deflater
# after having written more than FLUSH_EVERY_N_BYTES bytes of data
#
# @param data[String] data to be written
# @return self
def <<(data)
@deflater.deflate(data) { |chunk| @compressed_io << chunk }
@crc_buf << data
self
end
# Returns the amount of data received for writing, the amount of
# compressed data written and the CRC32 checksum. The return value
# can be directly used as the argument to {Streamer#update_last_entry_and_write_data_descriptor}
#
# @return [Hash] a hash of `{crc32, compressed_size, uncompressed_size}`
def finish
@compressed_io << @deflater.finish until @deflater.finished?
@crc_buf.flush
{crc32: @crc.to_i, compressed_size: @deflater.total_out, uncompressed_size: @deflater.total_in}
ensure
@deflater.close
end
end
Version data entries
8 entries across 8 versions & 1 rubygems