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(#2611) had suggested that an iterative version of SimpleHashFromByteSlice would be faster, presumably because we can envision some overhead accumulating from stack frames and function calls. Additionally, a recursive algorithm risks hitting the stack limit and causing a stack overflow should the tree be too large. Provided here is an iterative alternative, a simple test to assert correctness and a benchmark. On the performance side, there appears to be no overall difference: ``` BenchmarkSimpleHashAlternatives/recursive-4 20000 77677 ns/op BenchmarkSimpleHashAlternatives/iterative-4 20000 76802 ns/op ``` On the surface it might seem that the additional overhead is due to the different allocation patterns of the implementations. The recursive version uses a single `[][]byte` slices which it then re-slices at each level of the tree. The iterative version reproduces `[][]byte` once within the function and then rewrites sub-slices of that array at each level of the tree. Eexperimenting by modifying the code to simply calculate the hash and not store the result show little to no difference in performance. These preliminary results suggest: 1. The performance of the current implementation is pretty good 2. Go has low overhead for recursive functions 3. The performance of the SimpleHashFromByteSlice routine is dominated by the actual hashing of data Although this work is in no way exhaustive, point #3 suggests that optimizations of this routine would need to take an alternative approach to make significant improvements on the current performance. Finally, considering that the recursive implementation is easier to read, it might not be worthwhile to switch to a less intuitive implementation for so little benefit. * re-add slice re-writing * [crypto] Document SimpleHashFromByteSlicesIterative
crypto
crypto is the cryptographic package adapted for Tendermint's uses
Importing it
To get the interfaces,
import "github.com/tendermint/tendermint/crypto"
For any specific algorithm, use its specific module e.g.
import "github.com/tendermint/tendermint/crypto/ed25519"
If you want to decode bytes into one of the types, but don't care about the specific algorithm, use
import "github.com/tendermint/tendermint/crypto/amino"
Binary encoding
For Binary encoding, please refer to the Tendermint encoding spec.
JSON Encoding
crypto .Bytes() uses Amino:binary encoding, but Amino:JSON is also supported.
Example Amino:JSON encodings:
ed25519.PrivKeyEd25519 - {"type":"954568A3288910","value":"EVkqJO/jIXp3rkASXfh9YnyToYXRXhBr6g9cQVxPFnQBP/5povV4HTjvsy530kybxKHwEi85iU8YL0qQhSYVoQ=="}
ed25519.PubKeyEd25519 - {"type":"AC26791624DE60","value":"AT/+aaL1eB0477Mud9JMm8Sh8BIvOYlPGC9KkIUmFaE="}
crypto.PrivKeySecp256k1 - {"type":"019E82E1B0F798","value":"zx4Pnh67N+g2V+5vZbQzEyRerX9c4ccNZOVzM9RvJ0Y="}
crypto.PubKeySecp256k1 - {"type":"F8CCEAEB5AE980","value":"A8lPKJXcNl5VHt1FK8a244K9EJuS4WX1hFBnwisi0IJx"}