Created
February 2, 2012 20:00
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Encode & decode BSON::ObjectId into more friendly format (base64-like)
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class ObjectIdEncoder | |
attr_accessor :id | |
def initialize(id) | |
@id = id.to_a | |
raise "invalid ID!" unless @id.size == 12 | |
end | |
def encode | |
result = [] | |
4.times do |i| | |
base = i * 3 | |
tmp = @id[base + 2] | |
tmp |= @id[base + 1] << 8 | |
tmp |= @id[base] << 16 | |
result << TABLE[tmp >> 18] | |
result << TABLE[(tmp >> 12) & 0x3f] | |
result << TABLE[(tmp >> 6) & 0x3f] | |
result << TABLE[tmp & 0x3f] | |
end | |
result.join | |
end | |
end | |
class ObjectIdDecoder | |
attr_accessor :str_id | |
def initialize(str_id) | |
raise "invalid ID!" unless str_id.size == 16 | |
@str_id = str_id | |
end | |
def decode | |
result = [] | |
4.times do |i| | |
base = i * 4 | |
tmp = TABLE.index(@str_id[base + 3]) | |
tmp |= TABLE.index(@str_id[base + 2]) << 6 | |
tmp |= TABLE.index(@str_id[base + 1]) << 12 | |
tmp |= TABLE.index(@str_id[base]) << 18 | |
result << (tmp >> 16) | |
result << ((tmp >> 8) & 0xFF) | |
result << (tmp & 0xFF) | |
end | |
str_id = result.map { |x| "%.2x" % x }.join | |
BSON::ObjectId(str_id) | |
end | |
end |
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function ObjectIdEncode(id) { | |
var TABLE = "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-_"; | |
var idArray = [], result = [], i, base, triplet; | |
for (i = 0; i < 12; ++i) { | |
base = i * 2; | |
idArray.push(parseInt(id[base] + id[base + 1], 16)); | |
} | |
for (i = 0; i < 4; ++i) { | |
base = i * 3; | |
triplet = idArray[base + 2]; | |
triplet = triplet | idArray[base + 1] << 8; | |
triplet = triplet | idArray[base] << 16; | |
result.push(TABLE[triplet >> 18]); | |
result.push(TABLE[(triplet >> 12) & 0x3f]); | |
result.push(TABLE[(triplet >> 6) & 0x3f]); | |
result.push(TABLE[triplet & 0x3f]); | |
} | |
return result.join(""); | |
} |
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