refactor: remove encoding functions
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C997C339BE476FF2
131
src/encoding.ts
131
src/encoding.ts
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@ -1,131 +0,0 @@
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import { addContextToErr } from "./err.js";
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import { Err } from "./types.js";
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import { bytesToHex } from "@noble/hashes/utils";
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const MAX_UINT_64 = 18446744073709551615n;
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// b64ToBuf will take an untrusted base64 string and convert it into a
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// Uin8Array, returning an error if the input is not valid base64.
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const b64regex = /^[0-9a-zA-Z-_/+=]*$/;
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function b64ToBuf(b64: string): [Uint8Array, Err] {
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// Check that the final string is valid base64.
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if (!b64regex.test(b64)) {
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return [new Uint8Array(0), "provided string is not valid base64"];
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}
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// Swap any '-' characters for '+', and swap any '_' characters for '/'
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// for use in the atob function.
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b64 = b64.replaceAll("-", "+").replaceAll("_", "/");
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// Perform the conversion.
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const binStr = atob(b64);
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const len = binStr.length;
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const buf = new Uint8Array(len);
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for (let i = 0; i < len; i++) {
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buf[i] = binStr.charCodeAt(i);
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}
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return [buf, null];
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}
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// bufToHex takes a Uint8Array as input and returns the hex encoding of those
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// bytes as a string.
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function bufToHex(buf: Uint8Array): string {
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return bytesToHex(buf);
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}
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// bufToB64 will convert a Uint8Array to a base64 string with URL encoding and
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// no padding characters.
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function bufToB64(buf: Uint8Array): string {
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const b64Str = btoa(String.fromCharCode(...buf));
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return b64Str.replaceAll("+", "-").replaceAll("/", "_").replaceAll("=", "");
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}
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// bufToStr takes an ArrayBuffer as input and returns a text string. bufToStr
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// will check for invalid characters.
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function bufToStr(buf: ArrayBuffer): [string, Err] {
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try {
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const text = new TextDecoder("utf-8", { fatal: true }).decode(buf);
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return [text, null];
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} catch (err: any) {
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return [
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"",
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addContextToErr(err.toString(), "unable to decode ArrayBuffer to string"),
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];
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}
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}
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// decodeU64 is the opposite of encodeU64, it takes a uint64 encoded as 8 bytes
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// and decodes them into a BigInt.
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function decodeU64(u8: Uint8Array): [bigint, Err] {
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// Check the input.
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if (u8.length !== 8) {
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return [0n, "input should be 8 bytes"];
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}
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// Process the input.
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let num = 0n;
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for (let i = u8.length - 1; i >= 0; i--) {
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num *= 256n;
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num += BigInt(u8[i]);
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}
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return [num, null];
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}
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// encodeU64 will encode a bigint in the range of a uint64 to an 8 byte
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// Uint8Array.
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function encodeU64(num: bigint): [Uint8Array, Err] {
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// Check the bounds on the bigint.
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if (num < 0) {
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return [new Uint8Array(0), "expected a positive integer"];
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}
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if (num > MAX_UINT_64) {
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return [new Uint8Array(0), "expected a number no larger than a uint64"];
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}
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// Encode the bigint into a Uint8Array.
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const encoded = new Uint8Array(8);
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for (let i = 0; i < encoded.length; i++) {
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encoded[i] = Number(num & 0xffn);
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num = num >> 8n;
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}
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return [encoded, null];
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}
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// hexToBuf takes an untrusted string as input, verifies that the string is
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// valid hex, and then converts the string to a Uint8Array.
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const allHex = /^[0-9a-f]+$/i;
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function hexToBuf(hex: string): [Uint8Array, Err] {
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// The rest of the code doesn't handle zero length input well, so we handle
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// that separately. It's not an error, we just return an empty array.
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if (hex.length === 0) {
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return [new Uint8Array(0), null];
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}
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// Check that the length makes sense.
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if (hex.length % 2 !== 0) {
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return [new Uint8Array(0), "input has incorrect length"];
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}
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// Check that all of the characters are legal.
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if (!allHex.test(hex)) {
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return [new Uint8Array(0), "input has invalid character"];
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}
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// Create the buffer and fill it.
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const matches = hex.match(/.{2}/g);
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if (matches === null) {
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return [new Uint8Array(0), "input is incomplete"];
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}
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const u8 = new Uint8Array(matches.map((byte) => parseInt(byte, 16)));
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return [u8, null];
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}
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export {
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b64ToBuf,
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bufToB64,
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bufToStr,
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decodeU64,
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encodeU64,
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bufToHex,
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hexToBuf,
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};
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@ -28,7 +28,6 @@ export * from "./err.js";
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export * from "./errTracker.js";
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export * from "./types.js";
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export * from "./cid.js";
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export * from "./encoding.js";
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export * from "./keys.js";
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export * from "./download.js";
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export * from "./upload.js";
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