Undo blocks

[chrisguida]

This is some code I wrote a few years ago to add parsing of the undo blocks.

This is useful for creating bip158 compact block filters since they commit to the previous output scripts in addition to the current output scripts, and the corresponding rev*.dat files are stored alongside the regular blk files.

[pep8speaks]

Hello @chrisguida! Thanks for opening this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file blockchain_parser/blockchain.py:

Line 45:1: E302 expected 2 blank lines, found 1 Line 47:80: E501 line too long (81 > 79 characters)

• In the file blockchain_parser/transaction.py:

Line 14:80: E501 line too long (80 > 79 characters) Line 68:80: E501 line too long (82 > 79 characters)

• In the file blockchain_parser/undo.py:

Line 14:1: E302 expected 2 blank lines, found 1 Line 49:80: E501 line too long (87 > 79 characters) Line 60:72: W291 trailing whitespace Line 72:80: E501 line too long (107 > 79 characters) Line 87:80: E501 line too long (108 > 79 characters) Line 118:80: E501 line too long (84 > 79 characters) Line 127:80: E501 line too long (101 > 79 characters) Line 135:1: W293 blank line contains whitespace Line 136:5: E303 too many blank lines (2) Line 144:1: E303 too many blank lines (3) Line 171:80: E501 line too long (110 > 79 characters) Line 174:80: E501 line too long (83 > 79 characters)

• In the file blockchain_parser/utils.py:

Line 87:80: E501 line too long (99 > 79 characters) Line 101:1: W293 blank line contains whitespace Line 110:42: E228 missing whitespace around modulo operator Line 122:80: E501 line too long (117 > 79 characters) Line 129:80: E501 line too long (97 > 79 characters)

• In the file examples/undo-blocks.py:

Line 14:80: E501 line too long (90 > 79 characters)

[chrisguida]

:tada: