cerc-io/eth-iterator-utils
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This commit is contained in:
Roy Crihfield 2020-08-31 22:22:40 -05:00
parent d82b49b8ba
commit a3595be72b
1 changed files with 4 additions and 3 deletions
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7
pkg/iterator/iterator.go
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@ -119,8 +119,9 @@ func (gen *prefixGenerator) Next() {
} }
} }
// Generates ordered cartesian product of all nibbles of given length, w/ optional prefix // Generates paths that cut the trie domain into "nbins" bins, w/ optional prefix
// eg. MakePaths([4], 2) => [[4 0 0] [4 0 1] ... [4 f f]] // eg. MakePaths([], 2) => [[0] [8]]
// MakePaths([4], 32) => [[4 0 0] [4 0 8] [4 1 0]... [4 f 8]]
func MakePaths(prefix []byte, nbins uint) [][]byte { func MakePaths(prefix []byte, nbins uint) [][]byte {
var res [][]byte var res [][]byte
for it := newPrefixGenerator(nbins); it.HasNext(); it.Next() { for it := newPrefixGenerator(nbins); it.HasNext(); it.Next() {
@ -132,7 +133,7 @@ func MakePaths(prefix []byte, nbins uint) [][]byte {
return res return res
} }
// Apply a function to 16^cutdepth subtries divided by path prefix // Apply a function to nbins subtries divided according to path prefix
func VisitSubtries(tree state.Trie, nbins uint, callback func(NodeIterator)) { func VisitSubtries(tree state.Trie, nbins uint, callback func(NodeIterator)) {
prefixes := MakePaths(nil, nbins) prefixes := MakePaths(nil, nbins)
// pre- and postpend nil to include root & tail // pre- and postpend nil to include root & tail