bz2.js

/*! bz2 (C) 2019-present SheetJS LLC */

'use strict';

(function bz2() {
// https://www.ncbi.nlm.nih.gov/IEB/ToolBox/CPP_DOC/lxr/source/src/util/compress/bzip2/crctable.c
  const crc32Table = [
    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
    0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
    0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
    0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
    0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
    0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
    0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
    0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
    0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
    0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
    0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
    0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
    0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
    0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
    0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
    0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
    0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
    0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
    0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
    0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
    0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
    0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4,
  ];

  // generated from 1 << i, except for 32
  const masks = [
    0x00000000, 0x00000001, 0x00000003, 0x00000007,
    0x0000000f, 0x0000001f, 0x0000003f, 0x0000007f,
    0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff,
    0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff,
    0x0000ffff, 0x0001ffff, 0x0003ffff, 0x0007ffff,
    0x000fffff, 0x001fffff, 0x003fffff, 0x007fffff,
    0x00ffffff, 0x01ffffff, 0x03ffffff, 0x07ffffff,
    0x0fffffff, 0x1fffffff, 0x3fffffff, -0x80000000,
  ];

  function createOrderedHuffmanTable(lengths) {
    const z = [];
    for (let i = 0; i < lengths.length; i += 1) {
      z.push([i, lengths[i]]);
    }
    z.push([lengths.length, -1]);
    const table = [];
    let start = z[0][0];
    let bits = z[0][1];
    for (let i = 0; i < z.length; i += 1) {
      const finish = z[i][0];
      const endbits = z[i][1];
      if (bits) {
        for (let code = start; code < finish; code += 1) {
          table.push({ code, bits, symbol: undefined });
        }
      }
      start = finish;
      bits = endbits;
      if (endbits === -1) {
        break;
      }
    }
    table.sort((a, b) => ((a.bits - b.bits) || (a.code - b.code)));
    let tempBits = 0;
    let symbol = -1;
    const fastAccess = [];
    let current;
    for (let i = 0; i < table.length; i += 1) {
      const t = table[i];
      symbol += 1;
      if (t.bits !== tempBits) {
        symbol <<= t.bits - tempBits;
        tempBits = t.bits;
        current = fastAccess[tempBits] = {};
      }
      t.symbol = symbol;
      current[symbol] = t;
    }
    return {
      table,
      fastAccess,
    };
  }

  function bwtReverse(src, primary) {
    if (primary < 0 || primary >= src.length) {
      throw RangeError('Out of bound');
    }
    const unsorted = src.slice();
    src.sort((a, b) => a - b);
    const start = {};
    for (let i = src.length - 1; i >= 0; i -= 1) {
      start[src[i]] = i;
    }
    const links = [];
    for (let i = 0; i < src.length; i += 1) {
      links.push(start[unsorted[i]]++); // eslint-disable-line no-plusplus
    }
    let i;
    const first = src[i = primary];
    const ret = [];
    for (let j = 1; j < src.length; j += 1) {
      const x = src[i = links[i]];
      if (x === undefined) {
        ret.push(255);
      } else {
        ret.push(x);
      }
    }
    ret.push(first);
    ret.reverse();
    return ret;
  }

  function decompress(bytes, checkCRC = false) {
    let index = 0;
    let bitfield = 0;
    let bits = 0;
    const read = (n) => {
      if (n >= 32) {
        const nd = n >> 1;
        return read(nd) * (1 << nd) + read(n - nd);
      }
      while (bits < n) {
        bitfield = (bitfield << 8) + bytes[index];
        index += 1;
        bits += 8;
      }
      const m = masks[n];
      const r = (bitfield >> (bits - n)) & m;
      bits -= n;
      bitfield &= ~(m << bits);
      return r;
    };

    const magic = read(16);
    if (magic !== 0x425A) { // 'BZ'
      throw new Error('Invalid magic');
    }
    const method = read(8);
    if (method !== 0x68) { // h for huffman
      throw new Error('Invalid method');
    }

    let blocksize = read(8);
    if (blocksize >= 49 && blocksize <= 57) { // 1..9
      blocksize -= 48;
    } else {
      throw new Error('Invalid blocksize');
    }

    let out = new Uint8Array(bytes.length * 1.5);
    let outIndex = 0;
    let newCRC = -1;
    while (true) {
      const blocktype = read(48);
      const crc = read(32) | 0;
      if (blocktype === 0x314159265359) {
        if (read(1)) {
          throw new Error('do not support randomised');
        }
        const pointer = read(24);
        const used = [];
        const usedGroups = read(16);
        for (let i = 1 << 15; i > 0; i >>= 1) {
          if (!(usedGroups & i)) {
            for (let j = 0; j < 16; j += 1) {
              used.push(false);
            }
            continue; // eslint-disable-line no-continue
          }
          const usedChars = read(16);
          for (let j = 1 << 15; j > 0; j >>= 1) {
            used.push(!!(usedChars & j));
          }
        }
        const groups = read(3);
        if (groups < 2 || groups > 6) {
          throw new Error('Invalid number of huffman groups');
        }
        const selectorsUsed = read(15);
        const selectors = [];
        const mtf = Array.from({ length: groups }, (_, i) => i);
        for (let i = 0; i < selectorsUsed; i += 1) {
          let c = 0;
          while (read(1)) {
            c += 1;
            if (c >= groups) {
              throw new Error('MTF table out of range');
            }
          }
          const v = mtf[c];
          for (let j = c; j > 0; mtf[j] = mtf[--j]) { // eslint-disable-line no-plusplus
          // nothing
          }
          selectors.push(v);
          mtf[0] = v;
        }
        const symbolsInUse = used.reduce((a, b) => a + b, 0) + 2;
        const tables = [];
        for (let i = 0; i < groups; i += 1) {
          let length = read(5);
          const lengths = [];
          for (let j = 0; j < symbolsInUse; j += 1) {
            if (length < 0 || length > 20) {
              throw new Error('Huffman group length outside range');
            }
            while (read(1)) {
              length -= (read(1) * 2) - 1;
            }
            lengths.push(length);
          }
          tables.push(createOrderedHuffmanTable(lengths));
        }
        const favourites = [];
        for (let i = 0; i < used.length - 1; i += 1) {
          if (used[i]) {
            favourites.push(i);
          }
        }
        let decoded = 0;
        let selectorPointer = 0;
        let t;
        let r;
        let repeat = 0;
        let repeatPower = 0;
        const buffer = [];
        while (true) {
          decoded -= 1;
          if (decoded <= 0) {
            decoded = 50;
            if (selectorPointer <= selectors.length) {
              t = tables[selectors[selectorPointer]];
              selectorPointer += 1;
            }
          }
          for (const b in t.fastAccess) {
            if (!Object.prototype.hasOwnProperty.call(t.fastAccess, b)) {
              continue; // eslint-disable-line no-continue
            }
            if (bits < b) {
              bitfield = (bitfield << 8) + bytes[index];
              index += 1;
              bits += 8;
            }
            r = t.fastAccess[b][bitfield >> (bits - b)];
            if (r) {
              bitfield &= masks[bits -= b];
              r = r.code;
              break;
            }
          }
          if (r >= 0 && r <= 1) {
            if (repeat === 0) {
              repeatPower = 1;
            }
            repeat += repeatPower << r;
            repeatPower <<= 1;
            continue; // eslint-disable-line no-continue
          } else {
            const v = favourites[0];
            for (; repeat > 0; repeat -= 1) {
              buffer.push(v);
            }
          }
          if (r === symbolsInUse - 1) {
            break;
          } else {
            const v = favourites[r - 1];
            // eslint-disable-next-line no-plusplus
            for (let j = r - 1; j > 0; favourites[j] = favourites[--j]) {
            // nothing
            }
            favourites[0] = v;
            buffer.push(v);
          }
        }
        const nt = bwtReverse(buffer, pointer);
        let i = 0;
        while (i < nt.length) {
          const c = nt[i];
          let count = 1;
          if ((i < nt.length - 4)
            && nt[i + 1] === c
            && nt[i + 2] === c
            && nt[i + 3] === c) {
            count = nt[i + 4] + 4;
            i += 5;
          } else {
            i += 1;
          }
          if (outIndex + count >= out.length) {
            const old = out;
            out = new Uint8Array(old.length * 2);
            out.set(old);
          }
          for (let j = 0; j < count; j += 1) {
            if (checkCRC) {
              newCRC = (newCRC << 8) ^ crc32Table[((newCRC >> 24) ^ c) & 0xff];
            }
            out[outIndex] = c;
            outIndex += 1;
          }
        }
        if (checkCRC) {
          const calculatedCRC = newCRC ^ -1;
          if (calculatedCRC !== crc) {
            throw new Error(`CRC mismatch: ${calculatedCRC} !== ${crc}`);
          }
          newCRC = -1;
        }
      } else if (blocktype === 0x177245385090) {
        read(bits & 0x07); // pad align
        break;
      } else {
        throw new Error('Invalid bz2 blocktype');
      }
    }
    return out.subarray(0, outIndex);
  }

  const exports = { decompress };

  if (typeof window !== 'undefined') {
    window.bz2 = exports; // eslint-disable-line no-undef
  } else {
    module.exports = exports;
  }
}());