170 lines
4.9 KiB
JavaScript
170 lines
4.9 KiB
JavaScript
/**
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* Some data helpers.
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*
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*
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* @_subsection api/utils:Data Helpers [about-data]
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*/
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import { assert, assertArgument } from "./errors.js";
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function _getBytes(value, name, copy) {
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if (value instanceof Uint8Array) {
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if (copy) {
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return new Uint8Array(value);
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}
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return value;
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}
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if (typeof (value) === "string" && value.match(/^0x([0-9a-f][0-9a-f])*$/i)) {
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const result = new Uint8Array((value.length - 2) / 2);
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let offset = 2;
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for (let i = 0; i < result.length; i++) {
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result[i] = parseInt(value.substring(offset, offset + 2), 16);
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offset += 2;
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}
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return result;
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}
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assertArgument(false, "invalid BytesLike value", name || "value", value);
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}
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/**
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* Get a typed Uint8Array for %%value%%. If already a Uint8Array
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* the original %%value%% is returned; if a copy is required use
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* [[getBytesCopy]].
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*
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* @see: getBytesCopy
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*/
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export function getBytes(value, name) {
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return _getBytes(value, name, false);
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}
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/**
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* Get a typed Uint8Array for %%value%%, creating a copy if necessary
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* to prevent any modifications of the returned value from being
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* reflected elsewhere.
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*
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* @see: getBytes
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*/
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export function getBytesCopy(value, name) {
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return _getBytes(value, name, true);
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}
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/**
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* Returns true if %%value%% is a valid [[HexString]].
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*
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* If %%length%% is ``true`` or a //number//, it also checks that
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* %%value%% is a valid [[DataHexString]] of %%length%% (if a //number//)
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* bytes of data (e.g. ``0x1234`` is 2 bytes).
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*/
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export function isHexString(value, length) {
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if (typeof (value) !== "string" || !value.match(/^0x[0-9A-Fa-f]*$/)) {
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return false;
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}
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if (typeof (length) === "number" && value.length !== 2 + 2 * length) {
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return false;
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}
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if (length === true && (value.length % 2) !== 0) {
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return false;
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}
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return true;
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}
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/**
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* Returns true if %%value%% is a valid representation of arbitrary
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* data (i.e. a valid [[DataHexString]] or a Uint8Array).
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*/
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export function isBytesLike(value) {
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return (isHexString(value, true) || (value instanceof Uint8Array));
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}
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const HexCharacters = "0123456789abcdef";
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/**
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* Returns a [[DataHexString]] representation of %%data%%.
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*/
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export function hexlify(data) {
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const bytes = getBytes(data);
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let result = "0x";
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for (let i = 0; i < bytes.length; i++) {
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const v = bytes[i];
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result += HexCharacters[(v & 0xf0) >> 4] + HexCharacters[v & 0x0f];
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}
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return result;
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}
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/**
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* Returns a [[DataHexString]] by concatenating all values
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* within %%data%%.
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*/
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export function concat(datas) {
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return "0x" + datas.map((d) => hexlify(d).substring(2)).join("");
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}
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/**
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* Returns the length of %%data%%, in bytes.
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*/
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export function dataLength(data) {
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if (isHexString(data, true)) {
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return (data.length - 2) / 2;
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}
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return getBytes(data).length;
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}
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/**
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* Returns a [[DataHexString]] by slicing %%data%% from the %%start%%
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* offset to the %%end%% offset.
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*
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* By default %%start%% is 0 and %%end%% is the length of %%data%%.
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*/
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export function dataSlice(data, start, end) {
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const bytes = getBytes(data);
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if (end != null && end > bytes.length) {
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assert(false, "cannot slice beyond data bounds", "BUFFER_OVERRUN", {
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buffer: bytes, length: bytes.length, offset: end
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});
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}
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return hexlify(bytes.slice((start == null) ? 0 : start, (end == null) ? bytes.length : end));
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}
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/**
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* Return the [[DataHexString]] result by stripping all **leading**
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** zero bytes from %%data%%.
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*/
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export function stripZerosLeft(data) {
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let bytes = hexlify(data).substring(2);
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while (bytes.substring(0, 2) == "00") {
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bytes = bytes.substring(2);
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}
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return "0x" + bytes;
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}
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function zeroPad(data, length, left) {
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const bytes = getBytes(data);
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assert(length >= bytes.length, "padding exceeds data length", "BUFFER_OVERRUN", {
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buffer: new Uint8Array(bytes),
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length: length,
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offset: length + 1
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});
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const result = new Uint8Array(length);
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result.fill(0);
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if (left) {
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result.set(bytes, length - bytes.length);
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}
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else {
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result.set(bytes, 0);
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}
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return hexlify(result);
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}
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/**
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* Return the [[DataHexString]] of %%data%% padded on the **left**
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* to %%length%% bytes.
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*
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* If %%data%% already exceeds %%length%%, a [[BufferOverrun]] is
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* thrown.
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*
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* This pads data the same as **values** are in Solidity
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* (e.g. ``uint128``).
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*/
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export function zeroPadValue(data, length) {
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return zeroPad(data, length, true);
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}
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/**
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* Return the [[DataHexString]] of %%data%% padded on the **right**
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* to %%length%% bytes.
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*
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* If %%data%% already exceeds %%length%%, a [[BufferOverrun]] is
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* thrown.
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*
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* This pads data the same as **bytes** are in Solidity
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* (e.g. ``bytes16``).
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*/
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export function zeroPadBytes(data, length) {
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return zeroPad(data, length, false);
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}
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//# sourceMappingURL=data.js.map
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