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Base64 decode data: Difference between revisions
Added solution for F# using manual implementation
(Added solution for F# using .NET Library functions) |
(Added solution for F# using manual implementation) |
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Line 263:
let decoded = Convert.FromBase64String encoded
File.WriteAllBytes("favicon.ico", decoded)
</lang>
{{out}}
[https://rosettacode.org/favicon.ico Rosetta Code Icon]
===Manual Implementation===
<lang fsharp>
open System
open System.IO
let encoded = "AAABAAIAEBAAAAAAAABoBQAAJgAAACAgAAAAAAAAqAgAAI4FAAAoAAAAEAAAACAAAAABAAgAAAAAAEABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP///wCGiYcARkhHAL/CwAAmKScAam1rAOPm5ACgo6EAV1pYABcZGADO0c8AODs5AK2wrgBzdnQA6+7sAPz//QAAAwEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQBAYMBQUMBgQQEBAQEBAQBhEJDQsLDQkFBxAQEBAQBBEJEBAQEBAQEBAQEBAQEA0RDhAQEBAQEBAQEBAQEBAPCgoLEBAQEAkMDxAQEBAQEAsMEQwJAwoREQ8QERAQEAIGEAcNCAgLCwsQEBEQEA0DEBAQEBAQEBAQEBARDwQMBxAQEBAQEBAQEBAQEQMMAw8QEBAQEBAQEBAQEBEQEAgJEBAQEBAQEBAQEBAREBAEDBAQEBAQEBAQEBAQEQ4GBQgQEBAQEBAQEBAQEAQEBA8QEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAKAAAACAAAABAAAAAAQAIAAAAAACABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD///8AfoJ/AD9BQAC+wb8A3uHfAB8iIACeoZ8AXmFfAA4SEADO0c8ArrKvAG5xbwDu8e8AT1FPAI6RkAAuMS8A5unnABcaGADW2dcANjk3AMbJxwC2ubcAZmlnAHZ5dwD2+fcApqmoAJaamACGiYcABgkHAEZJRwBWWFcAKCspAIuNjACUlJQA8vXzAOrt6wAkJyUA4uXjANrd2wAyNTMA0tXTADo9OwDKzcsAwsXDALq9uwBiZWMAam1rAKKlowBydXMACwsLAPr9+wBKTkwAGx0cAFJVUwBbXVsAgoWDAEJFQwCqrKsAmpubACsuLACztrQAe398AAsPDABYW1kAiIyJAN3e3QDBwsEASUtKALm6uQCRk5IA+fn5AO3t7QAEBwUACAsJAPz//QD09/UA8PPxACEkIgDo6+kA5OflAODk4QAwMzEA2NvZADw/PQDQ09EAREdFAMzPzQCxtLIAYGNhAGRnZQBoa2kApKelAKCjoQB0d3UAnJ+dAISHhQCMj40Afn9+AMTGxQBNUE4AUFNRALzAvQBcX10AbHBtAICDgQCYmpkADxAPAPz8/AD4/PoA9vb2AB4gHwDy8vIA8PDwADU3NgBAQ0EAv8PAAKiqqQBvc3AAcXRyAJWYlgAGBwYA7e/uAOjp6ADIycgAXl9eAKaopgCUlpUA/f//AObn5wA8PT0A0NHRABYZFwD+/v4A+/78APv7+wAgIyEA+fv5ACIlIwD3+vgA+Pj4APf39wD1+PYAKi0rAPP29AAsLy0A8/PzAPH08gDp7OoANzo4AOXo5gA7PjwA4+bkAN/i4ABDRkQA3eDeAEVIRgDb3twAR0pIANXZ1gDT1tQAUVRSAMvOzABXWlgAyczKAFlcWgDFyMYAX2JgAMHEwgBhZGIAY2ZkAGVoZgC7vrwAZ2poALm8ugBpbGoAa25sALW4tgC0t7UAdXh2AHd6eACjpqQAoaSiAIGEggCDhoQAnaCeAIWIhgCbnpwAh4qIAJmcmgCKjYsAi46MAI2QjgCSlJMAkJSRAAoLCgAKDAsAGBoZAP3+/QD8/f0A7/HwADEzMgDv8O8A7O/tAOzt7ADn6ugA3+DfANzf3QBIS0kA2dvaAExPTQBPUlAAW15cAMDDwQC9wL4AuLu5AHx/fQCnqqgAfYB+AImMigCPkpAAk5aUAA8QEAAPEhAAHiEfACEjIQD+//8A/v/+AP3//gD9/v4A/P79APv//AD7/v0A/P78APv9/AD7/PwA+/37AC4wLwD5/PoA+fv6APj7+QD4+fkA+Pn4APb69wD3+fcA9/j3APb49wDy9PMA8fPyAO/z8QDw8vEA8PHwAERGRQDu8u8A7/HvAEVHRgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAIaFhenp6enphobmhYWF5osjeiRPzXvNTyR6I4uFhcYAgAEBAQEBAQEBAQEBAQEBzaKyfrsbeBu7fj0rlgEBAQCGAQEBAQEBAQEBAQHuUS14GKeh0FaaVtChCLPd1fP0AIYBAUtLS0tL4wEBgS24ozkeodSqq62rqtTTnJqvZpgAhgEBS0tLS0sBhfeuDJGEj2ccXK4sFSyuXGAIlw620QCGAQFLS0vk5OLyn7hSHeDUtnzODUyLTA2bptm+RkOWAIYBAUtLS+IB5A0Wo98/odmUR8dL5OLkSzPwjpOSjIkAhgEBS0tL4gHoljBzSRJ3VwEBAQEBAQEBAQEBAQEBhQCGAQFLS0viAYaW2R5Kxa/VhgEBAQEBAQEB4vBM8WzsAIYBAUtLS+TixvrWpcR5/7Z6AQEBAQEBAQEmPRsaKcsA5gEBAeRLS+QB45lB7TIGF7JRevvIDcpImbY3UjS1mwDlAQEB4ktLSwEBSysCgoRO0l4PB7UwOyFeOd4ACWATAO5ucSMzS0vkAYX2UbHYVuHgEERnqi4f/Mlva8OI3CcA/QTdWE3k5AEBlKQLtl29YqpA1C6rLghnZ31nfXZ0TwBQvJUxEQEBASPVIXa6183MoK7ZB1+9BwvWY6h0VyMZAFFeEmdQAQHyn8Bnr3VCAQEBk1EToClTlpDw80zqAeYAJj4lF08BhdF+L1lqUIcBAQHkM/Dwi+6G5OLi4gEB5gCYAo9oJAF7fjFbRoMBAQFL4gEBAQEBAQEBAQEBAQHpAFC3INQVmFhbZAJV6wEB5Evk5OLi4uLi4uTk5OQBAekAEUGKyRi/qhQDwU0BAeRLS0tLS0tLS0tLS0tLSwEB6QDNYQY1DmdkVKF/nWyF5EtLS0tLS0tLS0tLS0tLAQHpABFBinK4IkbYs7d+KfXj5EtLS0tLS0tLS0tLS0sBAekAmGkgLidwkgq5L69+/gEBS0tLS0tLS0tLS0tLSwEB6QAm2jyzAQEBhqxanr8kAQFLS0tLS0tLS0tLS0tLAQHpAJjaJS4FR43P2VkORssBAUtLS0tLS0tLS0tLS0sBAekAUNiEKrlFOkGrZbALIwEBS0tLS0tLS0tLS0tLSwEB6QBPwjwoMduzNh6puZ/wAeJLS0tLS0tLS0tLS0tLAQHpAPl0d6u3wDi0t36g+Evk5EtLS0tLS0tLS0tLS0sBAekAi0ykLQR0LAomkOIBAQEBAQEBAQEBAQEBAQEBAQEB6QDkAQHkbRnnAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAOaFhYbu7zPmhYWF5oaGhoaGhoaGhoaGhoaGhoaFhekA/////wAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAEAAAABAAAAAQAAAAE="
let decode (s: string) =
let chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".ToCharArray()
let filtered = String.filter (fun c -> Array.contains c chars || c = '=') s
let paddingSize = filtered |> String.filter ((=) '=') |> String.length
let s = filtered.Replace('=', 'A').ToCharArray() |> Array.map int
let ints = chars |> Array.map int
let calc c =
let n = [c..(c + 3)]
|> List.sumBy (fun k -> Array.IndexOf(ints, s.[k]) <<< (18 - 6 * (k % 4)))
[16; 8; 0]
|> List.map (fun k -> (n >>> k) &&& 255 |> char |> string) |> List.reduce (+)
[0..4..Array.length s - 1]
|> List.map calc
|> List.reduce (+)
|> fun r -> r.Substring(0, String.length r - paddingSize).ToCharArray()
|> Array.map byte
let decoded = decode encoded
File.WriteAllBytes("favicon.ico", decoded)
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