merkle

Annotated example explaining how to use this package

// First, we create a cache writer with caching policy and layer read-writer factory:
cacheWriter := cache.NewWriter(cache.MinHeightPolicy(0), cache.MakeSliceReadWriterFactory())

// We then initialize the tree:
tree, err := NewTreeBuilder().WithCacheWriter(cacheWriter).Build()
if err != nil {
	fmt.Println("Error while building the tree:", err.Error())
	return
}

// We add the leaves one-by-one:
for i := uint64(0); i < 8; i++ {
	err := tree.AddLeaf(NewNodeFromUint64(i))
	if err != nil {
		fmt.Println("Error while adding a leaf:", err.Error())
		return
	}
}

// After adding some leaves we can access the root of the tree:
fmt.Println(tree.Root()) // 89a0f1577268cc19b0a39c7a69f804fd140640c699585eb635ebb03c06154cce

// If we need to generate a proof, we could derive the proven leaves from the root. Here we create a static set:
leavesToProve := setOf(0, 4, 7)

// We get a cache reader from the cache writer:
cacheReader, err := cacheWriter.GetReader()
if err != nil {
	fmt.Println("Error while getting cache reader:", err.Error())
	return
}

// We pass the cache into GenerateProof along with the set of leaves to prove:
sortedProvenLeafIndices, provenLeaves, proof, err := GenerateProof(leavesToProve, cacheReader)
if err != nil {
	fmt.Println("Error while getting generating proof:", err.Error())
	return
}

// We now have access to a sorted list of proven leaves, the values of those leaves and the Merkle proof for them:
fmt.Println(sortedProvenLeafIndices) // 0 4 7
fmt.Println(nodes(provenLeaves))     // 0000 0400 0700
fmt.Println(nodes(proof))            // 0100 0094 0500 0600

// We can validate these values using ValidatePartialTree:
valid, err := ValidatePartialTree(sortedProvenLeafIndices, provenLeaves, proof, tree.Root(), GetSha256Parent)
if err != nil {
	fmt.Println("Error while validating proof:", err.Error())
	return
}
fmt.Println(valid) // true

/***************************************************
|                       89a0                       |
|           ba94                    633b           |
|     cb59       .0094.       bd50        fa67     |
| =0000=.0100. 0200  0300 =0400=.0500..0600.=0700= |
***************************************************/****/

Output: