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minor changes in zstd_compression_format.md

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inikep 2016-08-25 15:19:37 +02:00
parent de9d13068f
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zstd_compression_format.md
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@ -993,7 +993,7 @@ The table has a size of `tableSize = 1 << Accuracy_Log`.
Each cell describes the symbol decoded,
and instructions to get the next state.
Symbols are scanned in their natural order for `less than 1` probabilities.
Symbols are scanned in their natural order for "less than 1" probabilities.
Symbols with this probability are being attributed a single cell,
starting from the end of the table.
These symbols define a full state reset, reading `Accuracy_Log` bits.
@ -1098,13 +1098,13 @@ otherwise bitstream is considered corrupted.
##### Repeat offsets
As seen in [Offset Codes], the first 3 values define a repeated offset.
They are sorted in recency order, with 1 meaning "most recent one".
As seen in [Offset Codes], the first 3 values define a repeated offset and we will call them `Repeated_Offset1`, `Repeated_Offset2`, and `Repeated_Offset3`.
They are sorted in recency order, with `Repeated_Offset1` meaning "most recent one".
There is an exception though, when current sequence's literals length is `0`.
In which case, repcodes are "pushed by one",
so 1 becomes 2, 2 becomes 3,
and 3 becomes "offset_1 - 1_byte".
In which case, repeated offsets are "pushed by one",
so `Repeated_Offset1` becomes `Repeated_Offset2`, `Repeated_Offset2` becomes `Repeated_Offset3`,
and `Repeated_Offset3` becomes `Repeated_Offset1 - 1_byte`.
On first block, offset history is populated by the following values : 1, 4 and 8 (in order).
@ -1119,8 +1119,8 @@ they do not contribute to offset history.
New offset take the lead in offset history,
up to its previous place if it was already present.
It means that when repeat offset 1 (most recent) is used, history is unmodified.
When repeat offset 2 is used, it's swapped with offset 1.
It means that when `Repeated_Offset1` (most recent) is used, history is unmodified.
When `Repeated_Offset2` is used, it's swapped with `Repeated_Offset1`.
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