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Non-canonical LEB128 #892

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Non-canonical LEB128
jfbastien Dec 8, 2016
8c0b88f
s/significant/relevant/
jfbastien Dec 8, 2016
761eeb3
Rephrase the size limit
jfbastien Dec 9, 2016
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Expand Up @@ -53,6 +53,15 @@ represented by _at most_ ceil(_N_/7) bytes that may contain padding `0x80` or `0

Note: Currently, the only sizes used are `varint7`, `varint32` and `varint64`.

### Non-canonical LEB128

Both `varuintN` and `varintN` can be encoded with *non-canonical* LEB128 values where:

* non-relevant zero `0x80` bytes are present in an over-large encoding; and / or
* non-relevant LEB128 bits (bits past the size) are ignored.

The total number of bytes used to encode the `varuintN` / `varintN` cannot exceed the largest *canonical* encoding for that `varuintN` / `varintN`.

## Language Types

All types are distinguished by a negative `varint7` values that is the first byte of their encoding (representing a type constructor):
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