@chainsafe/ssz
Version:
Simple Serialize
159 lines • 6.78 kB
JavaScript
import { allocUnsafe } from "@chainsafe/as-sha256";
import { merkleizeBlocksBytes } from "@chainsafe/persistent-merkle-tree";
import { cacheRoot, maxChunksToDepth, symbolCachedPermanentRoot, } from "../util/merkleize.js";
import { namedClass } from "../util/named.js";
import { ListBasicTreeView } from "../view/listBasic.js";
import { ListBasicTreeViewDU } from "../viewDU/listBasic.js";
import { ArrayType } from "./array.js";
import { addLengthNode, setChunksNode, tree_deserializeFromBytesArrayBasic, tree_serializeToBytesArrayBasic, value_deserializeFromBytesArrayBasic, value_serializeToBytesArrayBasic, } from "./arrayBasic.js";
/**
* List: ordered variable-length homogeneous collection, limited to N values
*
* Array of Basic type:
* - Basic types are max 32 bytes long so multiple values may be packed in the same node.
* - Basic types are never returned in a view wrapper, but their value representation
*/
export class ListBasicType extends ArrayType {
elementType;
limit;
typeName;
itemsPerChunk;
depth;
chunkDepth;
maxChunkCount;
fixedSize = null;
minSize;
maxSize;
isList = true;
isViewMutable = true;
mixInLengthBlockBytes = new Uint8Array(64);
mixInLengthBuffer = Buffer.from(this.mixInLengthBlockBytes.buffer, this.mixInLengthBlockBytes.byteOffset, this.mixInLengthBlockBytes.byteLength);
defaultLen = 0;
constructor(elementType, limit, opts) {
super(elementType, opts?.cachePermanentRootStruct);
this.elementType = elementType;
this.limit = limit;
if (!elementType.isBasic)
throw Error("elementType must be basic");
if (limit === 0)
throw Error("List limit must be > 0");
this.typeName = opts?.typeName ?? `List[${elementType.typeName}, ${limit}]`;
// TODO Check that itemsPerChunk is an integer
this.itemsPerChunk = 32 / elementType.byteLength;
this.maxChunkCount = Math.ceil((this.limit * elementType.byteLength) / 32);
this.chunkDepth = maxChunksToDepth(this.maxChunkCount);
// Depth includes the extra level for the length node
this.depth = this.chunkDepth + 1;
this.minSize = 0;
this.maxSize = this.limit * elementType.maxSize;
}
static named(elementType, limit, opts) {
return new (namedClass(ListBasicType, opts.typeName))(elementType, limit, opts);
}
getView(tree) {
return new ListBasicTreeView(this, tree);
}
getViewDU(node, cache) {
// cache type should be validated (if applicate) in the view
// biome-ignore lint/suspicious/noExplicitAny: We need to use `any` here explicitly
return new ListBasicTreeViewDU(this, node, cache);
}
commitView(view) {
return view.node;
}
commitViewDU(view, hcOffset = 0, hcByLevel = null) {
view.commit(hcOffset, hcByLevel);
return view.node;
}
cacheOfViewDU(view) {
return view.cache;
}
// Serialization + deserialization
value_serializedSize(value) {
return value.length * this.elementType.byteLength;
}
value_serializeToBytes(output, offset, value) {
return value_serializeToBytesArrayBasic(this.elementType, value.length, output, offset, value);
}
value_deserializeFromBytes(data, start, end) {
return value_deserializeFromBytesArrayBasic(this.elementType, data, start, end, this);
}
tree_serializedSize(node) {
return this.tree_getLength(node) * this.elementType.byteLength;
}
tree_serializeToBytes(output, offset, node) {
const chunksNode = this.tree_getChunksNode(node);
const length = this.tree_getLength(node);
return tree_serializeToBytesArrayBasic(this.elementType, length, this.chunkDepth, output, offset, chunksNode);
}
tree_deserializeFromBytes(data, start, end) {
return tree_deserializeFromBytesArrayBasic(this.elementType, this.chunkDepth, data, start, end, this);
}
// Helpers for TreeView
tree_getLength(node) {
return node.right.getUint(4, 0);
}
tree_setLength(tree, length) {
tree.rootNode = addLengthNode(tree.rootNode.left, length);
}
tree_getChunksNode(node) {
return node.left;
}
tree_chunksNodeOffset() {
// one more level for length, see setChunksNode below
return 1;
}
tree_setChunksNode(rootNode, chunksNode, newLength, hcOffset = 0, hcByLevel = null) {
return setChunksNode(rootNode, chunksNode, newLength, hcOffset, hcByLevel);
}
// Merkleization
hashTreeRoot(value) {
// Return cached mutable root if any
if (this.cachePermanentRootStruct) {
const cachedRoot = value[symbolCachedPermanentRoot];
if (cachedRoot) {
return cachedRoot;
}
}
const root = allocUnsafe(32);
const safeCache = true;
this.hashTreeRootInto(value, root, 0, safeCache);
// hashTreeRootInto will cache the root if cachePermanentRootStruct is true
return root;
}
hashTreeRootInto(value, output, offset, safeCache = false) {
if (this.cachePermanentRootStruct) {
const cachedRoot = value[symbolCachedPermanentRoot];
if (cachedRoot) {
output.set(cachedRoot, offset);
return;
}
}
super.hashTreeRootInto(value, this.mixInLengthBlockBytes, 0);
// mixInLength
this.mixInLengthBuffer.writeUIntLE(value.length, 32, 6);
// one for hashTreeRoot(value), one for length
const chunkCount = 2;
merkleizeBlocksBytes(this.mixInLengthBlockBytes, chunkCount, output, offset);
if (this.cachePermanentRootStruct) {
cacheRoot(value, output, offset, safeCache);
}
}
getBlocksBytes(value) {
const byteLen = this.value_serializedSize(value);
const blockByteLen = Math.ceil(byteLen / 64) * 64;
// reallocate this.blocksBuffer if needed
if (byteLen > this.blocksBuffer.length) {
// pad 1 chunk if maxChunkCount is not even
this.blocksBuffer = new Uint8Array(blockByteLen);
}
const blockBytes = this.blocksBuffer.subarray(0, blockByteLen);
const uint8Array = blockBytes.subarray(0, byteLen);
const dataView = new DataView(uint8Array.buffer, uint8Array.byteOffset, uint8Array.byteLength);
value_serializeToBytesArrayBasic(this.elementType, value.length, { uint8Array, dataView }, 0, value);
// all padding bytes must be zero, this is similar to set zeroHash(0)
this.blocksBuffer.subarray(byteLen, blockByteLen).fill(0);
return blockBytes;
}
}
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