27 lines
550 B
Go
27 lines
550 B
Go
package codes
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type Code struct {
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Value uint32
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Bits uint8
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}
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func CodeForIndex(index uint32) Code {
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switch {
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case index < 4:
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return Code{Value: index, Bits: 4}
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case index < 8:
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return Code{Value: 0b01000 + (index & 0b00011), Bits: 5}
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case index < 16:
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return Code{Value: 0b011000 + (index & 0b000111), Bits: 6}
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case index < 32:
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return Code{Value: 0b1000000 + (index & 0b0001111), Bits: 7}
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default:
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set := uint8(index / uint32(64))
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return Code{
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Value: (((2 << set) - 1) << 7) + (index % uint32(64)),
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Bits: set + 8,
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}
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}
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}
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