Vous pouvez construire un tableau d'octets dans un FFI:Tampon pour obtenir la bonne taille/performance
https://rubydoc.info/github/ffi/ffi/FFI/Buffer
et faire les opérations sur les bits de chaque octet:
#!/usr/bin/env ruby
require 'get_process_mem'
require 'ffi'
BIT_OP = {
get: 1,
set: 2,
clear: 3,
}
class BitStore
attr_accessor :buf, :size
def initialize(shape) # ex [10000,10000] [10,20,30], etc
@shp = shape
@size = 1;
shape.each do | sz |
@size *= sz
end
@size = max(next8(@size)/8, 8) + 1 # min size needed
clear = true
@buf = FFI::Buffer.new(@size,1,clear)
end
def max(x,y)
x > y ? x : y
end
def next8(val)
val % 8 == 0 ? val+8 : ((val / 8).to_i + 1)*8
end
def write_buf_to_file(fname)
fout = File.open(fname, "wb")
fout.write(@buf.get_bytes(0,@size))
fout.close
end
def check_position(coord_arr)
if coord_arr.size != @shp.size
raise "coord_arr size != shape size"
end
coord_arr.each_with_index do | coord, i |
if coord_arr[i] > @shp[i]-1
raise "coord index out of bounds "
end
end
end
def get_position(coord_arr)
position = coord_arr[0]
(1..coord_arr.size-1).each do | i |
position += coord_arr[i] * @shp.reverse[i]
end
return position
end
def bit_op(coord_arr, op)
check_position(coord_arr)
position = get_position(coord_arr)
offset = (position / 8).to_i
bit_pos = (position % 8)
bit_val = 1 << bit_pos
val = @buf.get_string(offset, 1)
numeric_value = val == "" ? 0 : val.unpack("C")[0]
case op
when BIT_OP[:get]
numeric_value = numeric_value & bit_val
return numeric_value > 0 ? "set" : "clear"
when BIT_OP[:set]
numeric_value = numeric_value | bit_val
when BIT_OP[:clear]
numeric_value = numeric_value & (bit_val ^ 0xff)
end
@buf.put_string(offset,[numeric_value].pack("C"))
return ""
end
end
def main
begin
rows = 10000
cols = 10000
b = BitStore.new([rows,cols])
puts "setting [3,0]"
b.bit_op([3,0],BIT_OP[:set])
is_set = b.bit_op([3,0],BIT_OP[:get])
puts is_set
puts "setting [8000,8000]"
b.bit_op([8000,8000],BIT_OP[:set])
is_set = b.bit_op([8000,8000],BIT_OP[:get])
puts is_set
puts "clearing [8000,8000]"
b.bit_op([8000,8000],BIT_OP[:clear])
is_set = b.bit_op([8000,8000],BIT_OP[:get])
puts is_set
mem = GetProcessMem.new
puts mem.inspect
rescue NoMemoryError => e
puts "NoMemoryError"
p e
p e.backtrace.inspect
end
end
main
L'utilisation de la mémoire est de 26 mo:
user1@debian10 /home/user1/rubynew > ./pack_testb.rb
setting [3,0]
set
setting [8000,8000]
set
clearing [8000,8000]
clear
#<GetProcessMem:0x000000a0 @mb=26.6953125 @gb=0.02606964111328125 @kb=27336.0 @bytes=0.27992064e8>
La structure des fichiers sur le disque:
b = BitStore.new([7,6])
puts "setting [3,0]"
b.bit_op([3,0],BIT_OP[:set])
is_set = b.bit_op([3,0],BIT_OP[:get])
puts is_set
b.write_buf_to_file("/tmp/the_buf.bin")
system("xxd /tmp/the_buf.bin")
puts "setting [6,5]"
b.bit_op([6,5],BIT_OP[:set])
is_set = b.bit_op([6,5],BIT_OP[:get])
puts is_set
b.write_buf_to_file("/tmp/the_buf.bin")
system("xxd /tmp/the_buf.bin")
setting [3,0]
00000000: 0800 0000 0000 0000 00
setting [6,5]
00000000: 0000 0000 0002 0000 00
