Unknown conditions with cost

[arvidn]

overview

This patch assign cost to some (currently unknown) condition codes, when the ENABLE_SOFTFORK_CONDITION flag is set. Setting this flag is a hard fork, and so is changing the costs of unknown conditions. This flag is intended to be set when the 2.0 hard fork activates.

The rationale for this change is to enable adding new conditions with cost as soft forks in the future. It is already possible to soft-fork in new conditions, but they must all have cost 0, since all unknown conditions currently have 0 cost.

the details

Currently, all defined condition codes fit in 1 byte, so ConditionOpcode is an alias for u8. This patch changes this to be an alias for u16. This allows the conditions parser to handle 2-byte conditions.

When the flag ENABLE_SOFTFORK_CONDITION is enabled, any 2-byte condition opcode whose first byte is 0x01 is assigned a cost equal to the second bytes value AND 0x07 multiplied by 200000, plus 1'000'000.

examples

bye 0	byte 1	cost
1	0	1'000'000
1	1	1'200'000
1	2	1'400'000
1	3	1'600'000
1	4	1'800'000
1	5	2'000'000
1	6	2'200'000
1	7	2'400'000
1	8	1'000'000
1	2	1'200'000
1	...	...
1	253	2'000'000
1	254	2'200'000
1	255	2'400'000

[coveralls-official]

Pull Request Test Coverage Report for Build 5091164883

• 35 of 38 (92.11%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.5%) to 61.156%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/gen/opcodes.rs	22	23	95.65%
src/gen/validation_error.rs	0	2	0.0%

Totals
Change from base Build 5083277513:	0.5%
Covered Lines:	825
Relevant Lines:	1349

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💛 - Coveralls

[richardkiss]

Seems reasonable.