cerc-io/eth-iterator-utils
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Don't modify arg in rewindPath

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This commit is contained in:
Roy Crihfield 2024-07-05 20:02:13 +08:00
parent eac1d8b517
commit 7aad19c85d
1 changed files with 4 additions and 3 deletions
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7
tracker/tracker.go
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@ -254,20 +254,21 @@ func (it *Iterator) Bounds() ([]byte, []byte) {
return nil, nil return nil, nil
} }
// Rewinds to the path of the previous (pre-order) node: // Returns the path, rewound to the previous (pre-order) node:
// If path is the root (empty) or a leaf path, it's returned.
// If the last byte of the path is zero, pops it (e.g. [1 0] => [1]). // If the last byte of the path is zero, pops it (e.g. [1 0] => [1]).
// Otherwise, decrements it and pads with 0xF to 64 bytes (e.g. [1] => [0 f f f ...]). // Otherwise, decrements it and pads with 0xF to 64 bytes (e.g. [1] => [0 f f f ...]).
// The passed slice is not modified. // The passed slice is not modified.
func rewindPath(path []byte) []byte { func rewindPath(path []byte) []byte {
if len(path) == 0 { if len(path) == 0 || path[len(path)-1] == 0x10 {
return path return path
} }
if path[len(path)-1] == 0 { if path[len(path)-1] == 0 {
return path[:len(path)-1] return path[:len(path)-1]
} }
path[len(path)-1]--
padded := make([]byte, 64) padded := make([]byte, 64)
i := copy(padded, path) i := copy(padded, path)
padded[len(path)-1]--
for ; i < len(padded); i++ { for ; i < len(padded); i++ {
padded[i] = 0xf padded[i] = 0xf
} }