450 lines
14 KiB
TypeScript
450 lines
14 KiB
TypeScript
import { Bzip2Error, BZIP2_ERROR_CODES } from '../errors.js';
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import type { IBitReader, IHuffmanGroup } from '../interfaces.js';
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// Re-export Bzip2Error for backward compatibility
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export { Bzip2Error };
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/**
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* Throw a BZIP2 error with proper error code
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*/
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function throwError(message: string, code: string = BZIP2_ERROR_CODES.INVALID_BLOCK_DATA): never {
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throw new Bzip2Error(message, code);
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}
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/**
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* BZIP2 decompression implementation
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*/
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export class Bzip2 {
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// CRC32 lookup table for BZIP2
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public readonly crcTable: readonly number[] = [
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0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
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0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
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0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x4c11db70, 0x48d0c6c7,
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0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
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0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3,
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0x709f7b7a, 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
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0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, 0xbaea46ef,
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0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
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0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb,
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0xceb42022, 0xca753d95, 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
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0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
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0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
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0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4,
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0x0808d07d, 0x0cc9cdca, 0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
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0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08,
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0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
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0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc,
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0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
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0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, 0xe0b41de7, 0xe4750050,
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0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
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0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
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0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
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0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 0x4f040d56, 0x4bc510e1,
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0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
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0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5,
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0x3f9b762c, 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
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0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, 0xf5ee4bb9,
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0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
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0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd,
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0xcda1f604, 0xc960ebb3, 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
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0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
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0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
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0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2,
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0x470cdd2b, 0x43cdc09c, 0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
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0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e,
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0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
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0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a,
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0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
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0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, 0xe3a1cbc1, 0xe760d676,
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0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
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0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
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0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
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0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4,
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];
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// State arrays initialized in header()
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private byteCount!: Int32Array;
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private symToByte!: Uint8Array;
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private mtfSymbol!: Int32Array;
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private selectors!: Uint8Array;
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/**
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* Create a bit reader from a byte array
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*/
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array(bytes: Uint8Array | Buffer): (n: number) => number {
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let bit = 0;
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let byte = 0;
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const BITMASK = [0, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff];
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return function (n: number): number {
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let result = 0;
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while (n > 0) {
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const left = 8 - bit;
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if (n >= left) {
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result <<= left;
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result |= BITMASK[left] & bytes[byte++];
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bit = 0;
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n -= left;
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} else {
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result <<= n;
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result |= (bytes[byte] & (BITMASK[n] << (8 - n - bit))) >> (8 - n - bit);
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bit += n;
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n = 0;
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}
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}
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return result;
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};
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}
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/**
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* Simple decompression from a buffer
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*/
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simple(srcbuffer: Uint8Array | Buffer, stream: (byte: number) => void): void {
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const bits = this.array(srcbuffer);
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const size = this.header(bits as IBitReader);
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let ret: number | null = 0;
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const bufsize = 100000 * size;
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const buf = new Int32Array(bufsize);
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do {
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ret = this.decompress(bits as IBitReader, stream, buf, bufsize, ret);
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} while (ret !== null);
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}
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/**
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* Parse BZIP2 header and return block size
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*/
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header(bits: IBitReader): number {
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this.byteCount = new Int32Array(256);
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this.symToByte = new Uint8Array(256);
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this.mtfSymbol = new Int32Array(256);
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this.selectors = new Uint8Array(0x8000);
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if (bits(8 * 3) !== 4348520) {
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throwError('No BZIP2 magic number found at start of stream', BZIP2_ERROR_CODES.NO_MAGIC_NUMBER);
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}
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const blockSize = (bits(8) as number) - 48;
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if (blockSize < 1 || blockSize > 9) {
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throwError('Invalid BZIP2 archive: block size must be 1-9', BZIP2_ERROR_CODES.INVALID_ARCHIVE);
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}
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return blockSize;
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}
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/**
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* Decompress a BZIP2 block
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*/
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decompress(
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bits: IBitReader,
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stream: (byte: number) => void,
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buf: Int32Array,
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bufsize: number,
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streamCRC?: number | null
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): number | null {
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const MAX_HUFCODE_BITS = 20;
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const MAX_SYMBOLS = 258;
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const SYMBOL_RUNA = 0;
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const SYMBOL_RUNB = 1;
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const GROUP_SIZE = 50;
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let crc = 0 ^ -1;
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// Read block header
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let headerHex = '';
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for (let i = 0; i < 6; i++) {
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headerHex += (bits(8) as number).toString(16);
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}
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// Check for end-of-stream marker
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if (headerHex === '177245385090') {
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const finalCRC = bits(32) as number | 0;
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if (finalCRC !== streamCRC) {
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throwError('CRC32 mismatch: stream checksum verification failed', BZIP2_ERROR_CODES.CRC_MISMATCH);
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}
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// Align stream to byte boundary
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bits(null);
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return null;
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}
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// Verify block signature (pi digits)
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if (headerHex !== '314159265359') {
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throwError('Invalid block header: expected pi signature (0x314159265359)', BZIP2_ERROR_CODES.INVALID_BLOCK_DATA);
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}
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const crcblock = bits(32) as number | 0;
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if (bits(1)) {
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throwError('Unsupported obsolete BZIP2 format version', BZIP2_ERROR_CODES.INVALID_ARCHIVE);
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}
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const origPtr = bits(24) as number;
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if (origPtr > bufsize) {
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throwError('Initial position larger than buffer size', BZIP2_ERROR_CODES.BUFFER_OVERFLOW);
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}
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// Read symbol map
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let symbolMapBits = bits(16) as number;
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let symTotal = 0;
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for (let i = 0; i < 16; i++) {
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if (symbolMapBits & (1 << (15 - i))) {
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const subMap = bits(16) as number;
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for (let j = 0; j < 16; j++) {
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if (subMap & (1 << (15 - j))) {
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this.symToByte[symTotal++] = 16 * i + j;
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}
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}
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}
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}
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// Read Huffman groups
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const groupCount = bits(3) as number;
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if (groupCount < 2 || groupCount > 6) {
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throwError('Invalid group count: must be between 2 and 6', BZIP2_ERROR_CODES.INVALID_HUFFMAN);
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}
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const nSelectors = bits(15) as number;
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if (nSelectors === 0) {
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throwError('Invalid selector count: cannot be zero', BZIP2_ERROR_CODES.INVALID_SELECTOR);
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}
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// Initialize MTF symbol array
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for (let i = 0; i < groupCount; i++) {
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this.mtfSymbol[i] = i;
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}
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// Read selectors using MTF decoding
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for (let i = 0; i < nSelectors; i++) {
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let j = 0;
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while (bits(1)) {
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j++;
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if (j >= groupCount) {
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throwError('Invalid MTF index: exceeds group count', BZIP2_ERROR_CODES.INVALID_HUFFMAN);
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}
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}
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const uc = this.mtfSymbol[j];
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for (let k = j - 1; k >= 0; k--) {
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this.mtfSymbol[k + 1] = this.mtfSymbol[k];
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}
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this.mtfSymbol[0] = uc;
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this.selectors[i] = uc;
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}
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// Build Huffman tables
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const symCount = symTotal + 2;
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const groups: IHuffmanGroup[] = [];
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const length = new Uint8Array(MAX_SYMBOLS);
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const temp = new Uint16Array(MAX_HUFCODE_BITS + 1);
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for (let j = 0; j < groupCount; j++) {
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let t = bits(5) as number;
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for (let i = 0; i < symCount; i++) {
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while (true) {
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if (t < 1 || t > MAX_HUFCODE_BITS) {
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throwError('Invalid Huffman code length: must be between 1 and 20', BZIP2_ERROR_CODES.INVALID_HUFFMAN);
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}
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if (!bits(1)) break;
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if (!bits(1)) t++;
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else t--;
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}
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length[i] = t;
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}
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let minLen = length[0];
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let maxLen = length[0];
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for (let i = 1; i < symCount; i++) {
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if (length[i] > maxLen) maxLen = length[i];
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else if (length[i] < minLen) minLen = length[i];
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}
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const hufGroup: IHuffmanGroup = {
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permute: new Int32Array(MAX_SYMBOLS),
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limit: new Int32Array(MAX_HUFCODE_BITS + 1),
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base: new Int32Array(MAX_HUFCODE_BITS + 1),
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minLen,
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maxLen,
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};
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groups[j] = hufGroup;
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const base = hufGroup.base;
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const limit = hufGroup.limit;
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let pp = 0;
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for (let i = minLen; i <= maxLen; i++) {
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for (let t = 0; t < symCount; t++) {
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if (length[t] === i) hufGroup.permute[pp++] = t;
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}
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}
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for (let i = minLen; i <= maxLen; i++) {
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temp[i] = 0;
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limit[i] = 0;
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}
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for (let i = 0; i < symCount; i++) {
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temp[length[i]]++;
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}
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pp = 0;
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let tt = 0;
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for (let i = minLen; i < maxLen; i++) {
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pp += temp[i];
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limit[i] = pp - 1;
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pp <<= 1;
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base[i + 1] = pp - (tt += temp[i]);
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}
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limit[maxLen] = pp + temp[maxLen] - 1;
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base[minLen] = 0;
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}
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// Initialize for decoding
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for (let i = 0; i < 256; i++) {
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this.mtfSymbol[i] = i;
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this.byteCount[i] = 0;
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}
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let runPos = 0;
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let count = 0;
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let symCountRemaining = 0;
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let selector = 0;
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let hufGroup = groups[0];
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let base = hufGroup.base;
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let limit = hufGroup.limit;
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// Main decoding loop
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while (true) {
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if (!symCountRemaining--) {
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symCountRemaining = GROUP_SIZE - 1;
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if (selector >= nSelectors) {
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throwError('Invalid selector index: exceeds available groups', BZIP2_ERROR_CODES.INVALID_SELECTOR);
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}
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hufGroup = groups[this.selectors[selector++]];
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base = hufGroup.base;
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limit = hufGroup.limit;
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}
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let i = hufGroup.minLen;
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let j = bits(i) as number;
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while (true) {
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if (i > hufGroup.maxLen) {
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throwError('Huffman decoding error: bit length exceeds maximum allowed', BZIP2_ERROR_CODES.INVALID_HUFFMAN);
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}
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if (j <= limit[i]) break;
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i++;
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j = (j << 1) | (bits(1) as number);
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}
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j -= base[i];
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if (j < 0 || j >= MAX_SYMBOLS) {
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throwError('Symbol index out of bounds during Huffman decoding', BZIP2_ERROR_CODES.INVALID_HUFFMAN);
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}
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const nextSym = hufGroup.permute[j];
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if (nextSym === SYMBOL_RUNA || nextSym === SYMBOL_RUNB) {
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if (!runPos) {
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runPos = 1;
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j = 0;
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}
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if (nextSym === SYMBOL_RUNA) j += runPos;
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else j += 2 * runPos;
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runPos <<= 1;
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continue;
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}
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if (runPos) {
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runPos = 0;
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const runLength = j;
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if (count + runLength > bufsize) {
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throwError('Run-length overflow: decoded run exceeds buffer capacity', BZIP2_ERROR_CODES.BUFFER_OVERFLOW);
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}
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const uc = this.symToByte[this.mtfSymbol[0]];
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this.byteCount[uc] += runLength;
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for (let t = 0; t < runLength; t++) {
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buf[count++] = uc;
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}
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}
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if (nextSym > symTotal) break;
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if (count >= bufsize) {
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throwError('Buffer overflow: decoded data exceeds buffer capacity', BZIP2_ERROR_CODES.BUFFER_OVERFLOW);
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}
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const mtfIndex = nextSym - 1;
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const uc = this.mtfSymbol[mtfIndex];
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for (let k = mtfIndex - 1; k >= 0; k--) {
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this.mtfSymbol[k + 1] = this.mtfSymbol[k];
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}
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this.mtfSymbol[0] = uc;
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const decodedByte = this.symToByte[uc];
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this.byteCount[decodedByte]++;
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buf[count++] = decodedByte;
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}
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if (origPtr < 0 || origPtr >= count) {
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throwError('Invalid original pointer: position outside decoded block', BZIP2_ERROR_CODES.INVALID_POSITION);
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}
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// Inverse BWT transform
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let j = 0;
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for (let i = 0; i < 256; i++) {
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const k = j + this.byteCount[i];
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this.byteCount[i] = j;
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j = k;
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}
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for (let i = 0; i < count; i++) {
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const uc = buf[i] & 0xff;
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buf[this.byteCount[uc]] |= i << 8;
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this.byteCount[uc]++;
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}
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// Output decoded data
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let pos = 0;
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let current = 0;
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let run = 0;
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if (count) {
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pos = buf[origPtr];
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current = pos & 0xff;
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pos >>= 8;
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run = -1;
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}
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let remaining = count;
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while (remaining) {
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remaining--;
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const previous = current;
|
|
pos = buf[pos];
|
|
current = pos & 0xff;
|
|
pos >>= 8;
|
|
|
|
let copies: number;
|
|
let outbyte: number;
|
|
|
|
if (run++ === 3) {
|
|
copies = current;
|
|
outbyte = previous;
|
|
current = -1;
|
|
} else {
|
|
copies = 1;
|
|
outbyte = current;
|
|
}
|
|
|
|
while (copies--) {
|
|
crc = ((crc << 8) ^ this.crcTable[((crc >> 24) ^ outbyte) & 0xff]) & 0xffffffff;
|
|
stream(outbyte);
|
|
}
|
|
|
|
if (current !== previous) run = 0;
|
|
}
|
|
|
|
crc = (crc ^ -1) >>> 0;
|
|
if ((crc | 0) !== (crcblock | 0)) {
|
|
throwError('CRC32 mismatch: block checksum verification failed', BZIP2_ERROR_CODES.CRC_MISMATCH);
|
|
}
|
|
|
|
const newStreamCRC = (crc ^ (((streamCRC || 0) << 1) | ((streamCRC || 0) >>> 31))) & 0xffffffff;
|
|
return newStreamCRC;
|
|
}
|
|
}
|