RFC Errata
RFC 8878, "Zstandard Compression and the 'application/zstd' Media Type", February 2021
Source of RFC: IETF - NON WORKING GROUP
Errata ID: 8085
Status: Reported
Type: Technical
Publication Format(s) : TEXT
Reported By: Nianqi Tang
Date Reported: 2024-08-19
Section 3.1.1.5 says:
+=======+==========+===========+===========+===========+============+ |offset_|literals_ | Repeated_ | Repeated_ | Repeated_ |Comment | | value | length | Offset1 | Offset2 | Offset3 | | +=======+==========+===========+===========+===========+============+ | | | 1 | 4 | 8 |starting | | | | | | |values | +-------+----------+-----------+-----------+-----------+------------+ | 1114| 11 | 1111 | 1 | 4 |non-repeat | +-------+----------+-----------+-----------+-----------+------------+ | 1| 22 | 1111 | 1 | 4 |repeat 1; no| | | | | | |change | +-------+----------+-----------+-----------+-----------+------------+ | 2225| 22 | 2222 | 1111 | 1 |non-repeat | +-------+----------+-----------+-----------+-----------+------------+ | 1114| 111 | 1111 | 2222 | 1111 |non-repeat | +-------+----------+-----------+-----------+-----------+------------+ | 3336| 33 | 3333 | 1111 | 2222 |non-repeat | +-------+----------+-----------+-----------+-----------+------------+ | 2| 22 | 1111 | 3333 | 2222 |repeat 2; | | | | | | |swap 1 & 2 | +-------+----------+-----------+-----------+-----------+------------+ | 3| 33 | 2222 | 1111 | 3333 |repeat 3; | | | | | | |rotate 3 to | | | | | | |1 | +-------+----------+-----------+-----------+-----------+------------+ | 1| 0 | 2221 | 2222 | 1111 |insert | | | | | | |resolved | | | | | | |offset | +-------+----------+-----------+-----------+-----------+------------+ | 1| 0 | 2222 | 2221 | 3333 |repeat 2 | +-------+----------+-----------+-----------+-----------+------------+
It should say:
+=======+==========+===========+===========+===========+============+ |offset_|literals_ | Repeated_ | Repeated_ | Repeated_ |Comment | | value | length | Offset1 | Offset2 | Offset3 | | +=======+==========+===========+===========+===========+============+ | | | 1 | 4 | 8 |starting | | | | | | |values | +-------+----------+-----------+-----------+-----------+------------+ | 1114| 11 | 1111 | 1 | 4 |non-repeat | +-------+----------+-----------+-----------+-----------+------------+ | 1| 22 | 1111 | 1 | 4 |repeat 1; no| | | | | | |change | +-------+----------+-----------+-----------+-----------+------------+ | 2225| 22 | 2222 | 1111 | 1 |non-repeat | +-------+----------+-----------+-----------+-----------+------------+ | 1114| 111 | 1111 | 2222 | 1111 |non-repeat | +-------+----------+-----------+-----------+-----------+------------+ | 3336| 33 | 3333 | 1111 | 2222 |non-repeat | +-------+----------+-----------+-----------+-----------+------------+ | 2| 22 | 1111 | 3333 | 2222 |repeat 2; | | | | | | |swap 1 & 2 | +-------+----------+-----------+-----------+-----------+------------+ | 3| 33 | 2222 | 1111 | 3333 |repeat 3; | | | | | | |rotate 3 to | | | | | | |1 | +-------+----------+-----------+-----------+-----------+------------+ | 3| 0 | 2221 | 2222 | 1111 |insert | | | | | | |resolved | | | | | | |offset | +-------+----------+-----------+-----------+-----------+------------+ | 1| 0 | 2222 | 2221 | 1111 |repeat 2 | +-------+----------+-----------+-----------+-----------+------------+
Notes:
According to the description in 3.1.1.5, an offset value 1 with literal length 0 shall use Repeated Offset 2. However, in the last row of the example table, this is not the case. Since the second-to-last row has no "3333" value, I believe that the fifth column in the last row should be "1111".