// Copyright 2018-2025 the Deno authors. MIT license.
// Copyright (c) 2014 Jameson Little. MIT License.
// This module is browser compatible.
/**
 * common code for base32 and base32hex encodings.
 */
import { validateBinaryLike } from "./_validate_binary_like.js";
const placeHolderPadLookup = [0, 1, , 2, 3, , 4];
function getPadLength(placeHoldersLen) {
    const maybeLen = placeHolderPadLookup[placeHoldersLen];
    if (typeof maybeLen !== "number") {
        throw new Error("Invalid pad length");
    }
    return maybeLen;
}
function getLens(b32) {
    const len = b32.length;
    if (len % 8 > 0) {
        throw new Error(`Cannot decode base32 string as the length must be a multiple of 8: received length ${len}`);
    }
    let validLen = b32.indexOf("=");
    if (validLen === -1)
        validLen = len;
    const placeHoldersLen = validLen === len ? 0 : 8 - (validLen % 8);
    return [validLen, placeHoldersLen];
}
function getByteLength(validLen, placeHoldersLen) {
    return ((validLen + placeHoldersLen) * 5) / 8 - getPadLength(placeHoldersLen);
}
/**
 * Decodes an encoded string with the given lookup table.
 *
 * @param b32 The string to encode.
 * @param lookup The lookup table
 * @returns The encoded string.
 */
export function decode(b32, lookup) {
    const revLookup = [];
    lookup.forEach((c, i) => (revLookup[c.charCodeAt(0)] = i));
    let tmp;
    const [validLen, placeHoldersLen] = getLens(b32);
    const arr = new Uint8Array(getByteLength(validLen, placeHoldersLen));
    let curByte = 0;
    // if there are placeholders, only get up to the last complete 8 chars
    const len = placeHoldersLen > 0 ? validLen - 8 : validLen;
    let i;
    for (i = 0; i < len; i += 8) {
        tmp = (revLookup[b32.charCodeAt(i)] << 20) |
            (revLookup[b32.charCodeAt(i + 1)] << 15) |
            (revLookup[b32.charCodeAt(i + 2)] << 10) |
            (revLookup[b32.charCodeAt(i + 3)] << 5) |
            revLookup[b32.charCodeAt(i + 4)];
        arr[curByte++] = (tmp >> 17) & 0xff;
        arr[curByte++] = (tmp >> 9) & 0xff;
        arr[curByte++] = (tmp >> 1) & 0xff;
        tmp = ((tmp & 1) << 15) |
            (revLookup[b32.charCodeAt(i + 5)] << 10) |
            (revLookup[b32.charCodeAt(i + 6)] << 5) |
            revLookup[b32.charCodeAt(i + 7)];
        arr[curByte++] = (tmp >> 8) & 0xff;
        arr[curByte++] = tmp & 0xff;
    }
    if (placeHoldersLen === 1) {
        tmp = (revLookup[b32.charCodeAt(i)] << 20) |
            (revLookup[b32.charCodeAt(i + 1)] << 15) |
            (revLookup[b32.charCodeAt(i + 2)] << 10) |
            (revLookup[b32.charCodeAt(i + 3)] << 5) |
            revLookup[b32.charCodeAt(i + 4)];
        arr[curByte++] = (tmp >> 17) & 0xff;
        arr[curByte++] = (tmp >> 9) & 0xff;
        arr[curByte++] = (tmp >> 1) & 0xff;
        tmp = ((tmp & 1) << 7) |
            (revLookup[b32.charCodeAt(i + 5)] << 2) |
            (revLookup[b32.charCodeAt(i + 6)] >> 3);
        arr[curByte++] = tmp & 0xff;
    }
    else if (placeHoldersLen === 3) {
        tmp = (revLookup[b32.charCodeAt(i)] << 19) |
            (revLookup[b32.charCodeAt(i + 1)] << 14) |
            (revLookup[b32.charCodeAt(i + 2)] << 9) |
            (revLookup[b32.charCodeAt(i + 3)] << 4) |
            (revLookup[b32.charCodeAt(i + 4)] >> 1);
        arr[curByte++] = (tmp >> 16) & 0xff;
        arr[curByte++] = (tmp >> 8) & 0xff;
        arr[curByte++] = tmp & 0xff;
    }
    else if (placeHoldersLen === 4) {
        tmp = (revLookup[b32.charCodeAt(i)] << 11) |
            (revLookup[b32.charCodeAt(i + 1)] << 6) |
            (revLookup[b32.charCodeAt(i + 2)] << 1) |
            (revLookup[b32.charCodeAt(i + 3)] >> 4);
        arr[curByte++] = (tmp >> 8) & 0xff;
        arr[curByte++] = tmp & 0xff;
    }
    else if (placeHoldersLen === 6) {
        tmp = (revLookup[b32.charCodeAt(i)] << 3) |
            (revLookup[b32.charCodeAt(i + 1)] >> 2);
        arr[curByte++] = tmp & 0xff;
    }
    return arr;
}
function encodeChunk(uint8, start, end, lookup) {
    let tmp;
    const output = [];
    for (let i = start; i < end; i += 5) {
        tmp = ((uint8[i] << 16) & 0xff0000) |
            ((uint8[i + 1] << 8) & 0xff00) |
            (uint8[i + 2] & 0xff);
        output.push(lookup[(tmp >> 19) & 0x1f]);
        output.push(lookup[(tmp >> 14) & 0x1f]);
        output.push(lookup[(tmp >> 9) & 0x1f]);
        output.push(lookup[(tmp >> 4) & 0x1f]);
        tmp = ((tmp & 0xf) << 16) |
            ((uint8[i + 3] << 8) & 0xff00) |
            (uint8[i + 4] & 0xff);
        output.push(lookup[(tmp >> 15) & 0x1f]);
        output.push(lookup[(tmp >> 10) & 0x1f]);
        output.push(lookup[(tmp >> 5) & 0x1f]);
        output.push(lookup[tmp & 0x1f]);
    }
    return output.join("");
}
/**
 * Encodes the given data using the lookup table.
 *
 * @param data The data to encode.
 * @param lookup The lookup table.
 * @returns The encoded string.
 */
export function encode(data, lookup) {
    const uint8 = validateBinaryLike(data);
    let tmp;
    const len = uint8.length;
    const extraBytes = len % 5;
    const parts = [];
    const maxChunkLength = 16385; // must be multiple of 5
    const len2 = len - extraBytes;
    // go through the array every 5 bytes, we'll deal with trailing stuff later
    for (let i = 0; i < len2; i += maxChunkLength) {
        parts.push(encodeChunk(uint8, i, i + maxChunkLength > len2 ? len2 : i + maxChunkLength, lookup));
    }
    // pad the end with zeros, but make sure to not forget the extra bytes
    if (extraBytes === 4) {
        tmp = ((uint8[len2] & 0xff) << 16) |
            ((uint8[len2 + 1] & 0xff) << 8) |
            (uint8[len2 + 2] & 0xff);
        parts.push(lookup[(tmp >> 19) & 0x1f]);
        parts.push(lookup[(tmp >> 14) & 0x1f]);
        parts.push(lookup[(tmp >> 9) & 0x1f]);
        parts.push(lookup[(tmp >> 4) & 0x1f]);
        tmp = ((tmp & 0xf) << 11) | (uint8[len2 + 3] << 3);
        parts.push(lookup[(tmp >> 10) & 0x1f]);
        parts.push(lookup[(tmp >> 5) & 0x1f]);
        parts.push(lookup[tmp & 0x1f]);
        parts.push("=");
    }
    else if (extraBytes === 3) {
        tmp = ((uint8[len2] & 0xff) << 17) |
            ((uint8[len2 + 1] & 0xff) << 9) |
            ((uint8[len2 + 2] & 0xff) << 1);
        parts.push(lookup[(tmp >> 20) & 0x1f]);
        parts.push(lookup[(tmp >> 15) & 0x1f]);
        parts.push(lookup[(tmp >> 10) & 0x1f]);
        parts.push(lookup[(tmp >> 5) & 0x1f]);
        parts.push(lookup[tmp & 0x1f]);
        parts.push("===");
    }
    else if (extraBytes === 2) {
        tmp = ((uint8[len2] & 0xff) << 12) | ((uint8[len2 + 1] & 0xff) << 4);
        parts.push(lookup[(tmp >> 15) & 0x1f]);
        parts.push(lookup[(tmp >> 10) & 0x1f]);
        parts.push(lookup[(tmp >> 5) & 0x1f]);
        parts.push(lookup[tmp & 0x1f]);
        parts.push("====");
    }
    else if (extraBytes === 1) {
        tmp = (uint8[len2] & 0xff) << 2;
        parts.push(lookup[(tmp >> 5) & 0x1f]);
        parts.push(lookup[tmp & 0x1f]);
        parts.push("======");
    }
    return parts.join("");
}
//# sourceMappingURL=_base32_common.js.map