Original bug ID: 5575
Reporter: lealanko
Assigned to: @damiendoligez
Status: closed (set by @damiendoligez on 2012-04-10T15:33:44Z)
Resolution: fixed
Priority: normal
Severity: minor
Version: 3.12.1
Fixed in version: 4.00.0+dev
Category: standard library
Related to: #5977
Monitored by: mehdi

Bug description

Although the Random module is designed so that it produces the same output on all architectures, the internal representation of a random state depends on the architecture: on 64-bit architectures, the state array contains some values that won't fit into an int on 32-bit architectures. Hence a Random.State.t from a 64-bit system cannot be marshalled and then unmarshalled on a 32-bit system.

This is trivial to fix: just add "land 0x3FFFFFFF" before storing a value in the state array.

Steps to reproduce

On 64-bit:

Marshal.to_string (Random.State.make [||]) [];;

• : string =
  "\132\149\166\190\000\000\001~\000\000\000\002\000\000\000;\000\000\000;\160\b\000\000\220\000\003\000\000\000\000\196\146\178\147\003\000\000\000\000\228FXM\002Q'\236\001\002f\239\t\161\002X\195\177F\002P\127W\144\0024r\149\203\003\000\000\000\000\139\133Ro\002K\146K|\002s\196\192)\003\000\000\000\000\173\178\021\209\002\b\194\202\003\000\000\000\000\152\137\186\224\003\000\000\000\000\231e\228\246\002r,,6\002yv\150\244\003\000\000\000\000\250\224\233T\003\000\000\000\000\135}\182\205\003\000\000\000\000\209\168V.\003\000\000\000\000\146\210t\176\002lo\025\003\000\000\000\000\255H8\199\002\017\243\136\188\002HPJx\003\000\000\000\000\228\207*n\002(\184\177Q\003\000\000\000\000\185}\186U\002\015k\206 \003\000\000\000\000\233>\185\222\002-\149\197\194\003\000\000\000\000\243\215[\186\0022=%\138\002-\231\218\025\002g\244\133Z\003\000\000\000\000\169\248\132\202\002d\235+\170\002n\217\147\149\002_\185$!\002c\137\162\200\002:\135fo\002X}\180U\003\000\000\000\000\164[u\234\002G\179\234=\003\000\000\000\000\230\156r\019\003\000\000\000\000\155\252\162\255\003\000\000\000\000\245b9\021\003\000\000\000\000\246\254\198\152\002\t\158R\222\002T\210%\205\003\000\000\000\000\203\252\207\213\003\000\000\000\000\233\011P\219\003\000\000\000\000\171\206\143'\003\000\000\000\000\133\244V\151\002+"\145\165\002\020\139\169\031@"

On 32-bit:

let s : Random.State.t = Marshal.from_string "\132\149\166\190\000\000\001~\000\000\000\002\000\000\000;\000\000\000;\160\b\000\000\220\000\003\000\000\000\000\196\146\178\147\003\000\000\000\000\228FXM\002Q'\236\001\002f\239\t\161\002X\195\177F\002P\127W\144\0024r\149\203\003\000\000\000\000\139\133Ro\002K\146K|\002s\196\192)\003\000\000\000\000\173\178\021\209\002\b\194\202\003\000\000\000\000\152\137\186\224\003\000\000\000\000\231e\228\246\002r,,6\002yv\150\244\003\000\000\000\000\250\224\233T\003\000\000\000\000\135}\182\205\003\000\000\000\000\209\168V.\003\000\000\000\000\146\210t\176\002lo\025\003\000\000\000\000\255H8\199\002\017\243\136\188\002HPJx\003\000\000\000\000\228\207*n\002(\184\177Q\003\000\000\000\000\185}\186U\002\015k\206 \003\000\000\000\000\233>\185\222\002-\149\197\194\003\000\000\000\000\243\215[\186\0022=%\138\002-\231\218\025\002g\244\133Z\003\000\000\000\000\169\248\132\202\002d\235+\170\002n\217\147\149\002_\185$!\002c\137\162\200\002:\135fo\002X}\180U\003\000\000\000\000\164[u\234\002G\179\234=\003\000\000\000\000\230\156r\019\003\000\000\000\000\155\252\162\255\003\000\000\000\000\245b9\021\003\000\000\000\000\246\254\198\152\002\t\158R\222\002T\210%\205\003\000\000\000\000\203\252\207\213\003\000\000\000\000\233\011P\219\003\000\000\000\000\171\206\143'\003\000\000\000\000\133\244V\151\002+"\145\165\002\020\139\169\031@" 0;;

Exception: Failure "input_value: integer too large".