fix #803 : wrong example in huffman bitstream section, reported by @ulikunitz
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@ -16,7 +16,7 @@ Distribution of this document is unlimited.
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### Version
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0.2.5 (31/03/17)
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0.2.6 (19/08/17)
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Introduction
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@ -1249,23 +1249,25 @@ Consequently, a last byte of `0` is not possible.
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And the final-bit-flag itself is not part of the useful bitstream.
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Hence, the last byte contains between 0 and 7 useful bits.
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For example, if the literal sequence "0145" was encoded using the prefix codes above,
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it would be encoded as:
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```
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00000001 01110000
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```
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|Symbol | 5 | 4 | 1 | 0 | Padding |
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|--------|------|------|----|---|---------|
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|Encoding|`0000`|`0001`|`01`|`1`| `10000` |
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Starting from the end,
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it's possible to read the bitstream in a __little-endian__ fashion,
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keeping track of already used bits. Since the bitstream is encoded in reverse
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order, by starting at the end the symbols can be read in forward order.
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order, starting from the end read symbols in forward order.
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Reading the last `Max_Number_of_Bits` bits,
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it's then possible to compare extracted value to decoding table,
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For example, if the literal sequence "0145" was encoded using above prefix code,
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it would be encoded (in reverse order) as:
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|Symbol | 5 | 4 | 1 | 0 | Padding |
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|--------|------|------|----|---|---------|
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|Encoding|`0000`|`0001`|`01`|`1`| `00001` |
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Resulting in following 2-bytes bitstream :
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```
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00010000 00001101
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```
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Reading highest `Max_Number_of_Bits` bits,
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it's possible to compare extracted value to decoding table,
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determining the symbol to decode and number of bits to discard.
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The process continues up to reading the required number of symbols per stream.
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@ -1516,12 +1518,13 @@ to crosscheck that an implementation build its decoding tables correctly.
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Version changes
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---------------
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- 0.2.6 : fixed an error in huffman example, by Ulrich Kunitz
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- 0.2.5 : minor typos and clarifications
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- 0.2.4 : section restructuring, by Sean Purcell
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- 0.2.3 : clarified several details, by Sean Purcell
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- 0.2.2 : added predefined codes, by Johannes Rudolph
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- 0.2.1 : clarify field names, by Przemyslaw Skibinski
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- 0.2.0 : numerous format adjustments for zstd v0.8
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- 0.2.0 : numerous format adjustments for zstd v0.8+
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- 0.1.2 : limit Huffman tree depth to 11 bits
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- 0.1.1 : reserved dictID ranges
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- 0.1.0 : initial release
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