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Size: 1.25 KB
Versions: 7
Compression:
Stored size: 1.25 KB
Contents
# frozen_string_literal: true
require 'image_size/reader'
class ImageSize
module ChunkyReader # :nodoc:
include Reader
# Size of a chunk in which to read
def chunk_size
4096
end
# Including class should define method chunk that accepts the chunk number
# and returns a string of chunk_size length or shorter for last chunk, or
# nil for further chunks.
# Determines required chunks, takes parts of them to construct desired
# substring, behaves same as str[start, length] except start can't be
# negative.
def [](offset, length)
raise ArgumentError, "expected offset not to be negative, got #{offset}" if offset < 0
return if length < 0
first = offset / chunk_size
return unless (first_chunk = chunk(first))
last = (offset + length - 1) / chunk_size
if first >= last
first_chunk[offset - (first * chunk_size), length]
else
return unless (first_piece = first_chunk[offset - (first * chunk_size), chunk_size])
chunks = (first.succ...last).map{ |i| chunk(i) }.unshift(first_piece)
if (last_chunk = chunk(last))
chunks.push(last_chunk[0, offset + length - (last * chunk_size)])
end
chunks.join
end
end
end
end
Version data entries
7 entries across 7 versions & 1 rubygems