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author | Minteck <contact@minteck.org> | 2023-01-10 14:54:04 +0100 |
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committer | Minteck <contact@minteck.org> | 2023-01-10 14:54:04 +0100 |
commit | 99c1d9af689e5325f3cf535c4007b3aeb8325229 (patch) | |
tree | e663b3c2ebdbd67c818ac0c5147f0ce1d2463cda /school/node_modules/pako/lib/inflate.js | |
parent | 9871b03912fc28ad38b4037ebf26a78aa937baba (diff) | |
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diff --git a/school/node_modules/pako/lib/inflate.js b/school/node_modules/pako/lib/inflate.js new file mode 100644 index 0000000..7535d15 --- /dev/null +++ b/school/node_modules/pako/lib/inflate.js @@ -0,0 +1,423 @@ +'use strict'; + + +var zlib_inflate = require('./zlib/inflate'); +var utils = require('./utils/common'); +var strings = require('./utils/strings'); +var c = require('./zlib/constants'); +var msg = require('./zlib/messages'); +var ZStream = require('./zlib/zstream'); +var GZheader = require('./zlib/gzheader'); + +var toString = Object.prototype.toString; + +/** + * class Inflate + * + * Generic JS-style wrapper for zlib calls. If you don't need + * streaming behaviour - use more simple functions: [[inflate]] + * and [[inflateRaw]]. + **/ + +/* internal + * inflate.chunks -> Array + * + * Chunks of output data, if [[Inflate#onData]] not overridden. + **/ + +/** + * Inflate.result -> Uint8Array|Array|String + * + * Uncompressed result, generated by default [[Inflate#onData]] + * and [[Inflate#onEnd]] handlers. Filled after you push last chunk + * (call [[Inflate#push]] with `Z_FINISH` / `true` param) or if you + * push a chunk with explicit flush (call [[Inflate#push]] with + * `Z_SYNC_FLUSH` param). + **/ + +/** + * Inflate.err -> Number + * + * Error code after inflate finished. 0 (Z_OK) on success. + * Should be checked if broken data possible. + **/ + +/** + * Inflate.msg -> String + * + * Error message, if [[Inflate.err]] != 0 + **/ + + +/** + * new Inflate(options) + * - options (Object): zlib inflate options. + * + * Creates new inflator instance with specified params. Throws exception + * on bad params. Supported options: + * + * - `windowBits` + * - `dictionary` + * + * [http://zlib.net/manual.html#Advanced](http://zlib.net/manual.html#Advanced) + * for more information on these. + * + * Additional options, for internal needs: + * + * - `chunkSize` - size of generated data chunks (16K by default) + * - `raw` (Boolean) - do raw inflate + * - `to` (String) - if equal to 'string', then result will be converted + * from utf8 to utf16 (javascript) string. When string output requested, + * chunk length can differ from `chunkSize`, depending on content. + * + * By default, when no options set, autodetect deflate/gzip data format via + * wrapper header. + * + * ##### Example: + * + * ```javascript + * var pako = require('pako') + * , chunk1 = Uint8Array([1,2,3,4,5,6,7,8,9]) + * , chunk2 = Uint8Array([10,11,12,13,14,15,16,17,18,19]); + * + * var inflate = new pako.Inflate({ level: 3}); + * + * inflate.push(chunk1, false); + * inflate.push(chunk2, true); // true -> last chunk + * + * if (inflate.err) { throw new Error(inflate.err); } + * + * console.log(inflate.result); + * ``` + **/ +function Inflate(options) { + if (!(this instanceof Inflate)) return new Inflate(options); + + this.options = utils.assign({ + chunkSize: 16384, + windowBits: 0, + to: '' + }, options || {}); + + var opt = this.options; + + // Force window size for `raw` data, if not set directly, + // because we have no header for autodetect. + if (opt.raw && (opt.windowBits >= 0) && (opt.windowBits < 16)) { + opt.windowBits = -opt.windowBits; + if (opt.windowBits === 0) { opt.windowBits = -15; } + } + + // If `windowBits` not defined (and mode not raw) - set autodetect flag for gzip/deflate + if ((opt.windowBits >= 0) && (opt.windowBits < 16) && + !(options && options.windowBits)) { + opt.windowBits += 32; + } + + // Gzip header has no info about windows size, we can do autodetect only + // for deflate. So, if window size not set, force it to max when gzip possible + if ((opt.windowBits > 15) && (opt.windowBits < 48)) { + // bit 3 (16) -> gzipped data + // bit 4 (32) -> autodetect gzip/deflate + if ((opt.windowBits & 15) === 0) { + opt.windowBits |= 15; + } + } + + this.err = 0; // error code, if happens (0 = Z_OK) + this.msg = ''; // error message + this.ended = false; // used to avoid multiple onEnd() calls + this.chunks = []; // chunks of compressed data + + this.strm = new ZStream(); + this.strm.avail_out = 0; + + var status = zlib_inflate.inflateInit2( + this.strm, + opt.windowBits + ); + + if (status !== c.Z_OK) { + throw new Error(msg[status]); + } + + this.header = new GZheader(); + + zlib_inflate.inflateGetHeader(this.strm, this.header); + + // Setup dictionary + if (opt.dictionary) { + // Convert data if needed + if (typeof opt.dictionary === 'string') { + opt.dictionary = strings.string2buf(opt.dictionary); + } else if (toString.call(opt.dictionary) === '[object ArrayBuffer]') { + opt.dictionary = new Uint8Array(opt.dictionary); + } + if (opt.raw) { //In raw mode we need to set the dictionary early + status = zlib_inflate.inflateSetDictionary(this.strm, opt.dictionary); + if (status !== c.Z_OK) { + throw new Error(msg[status]); + } + } + } +} + +/** + * Inflate#push(data[, mode]) -> Boolean + * - data (Uint8Array|Array|ArrayBuffer|String): input data + * - mode (Number|Boolean): 0..6 for corresponding Z_NO_FLUSH..Z_TREE modes. + * See constants. Skipped or `false` means Z_NO_FLUSH, `true` means Z_FINISH. + * + * Sends input data to inflate pipe, generating [[Inflate#onData]] calls with + * new output chunks. Returns `true` on success. The last data block must have + * mode Z_FINISH (or `true`). That will flush internal pending buffers and call + * [[Inflate#onEnd]]. For interim explicit flushes (without ending the stream) you + * can use mode Z_SYNC_FLUSH, keeping the decompression context. + * + * On fail call [[Inflate#onEnd]] with error code and return false. + * + * We strongly recommend to use `Uint8Array` on input for best speed (output + * format is detected automatically). Also, don't skip last param and always + * use the same type in your code (boolean or number). That will improve JS speed. + * + * For regular `Array`-s make sure all elements are [0..255]. + * + * ##### Example + * + * ```javascript + * push(chunk, false); // push one of data chunks + * ... + * push(chunk, true); // push last chunk + * ``` + **/ +Inflate.prototype.push = function (data, mode) { + var strm = this.strm; + var chunkSize = this.options.chunkSize; + var dictionary = this.options.dictionary; + var status, _mode; + var next_out_utf8, tail, utf8str; + + // Flag to properly process Z_BUF_ERROR on testing inflate call + // when we check that all output data was flushed. + var allowBufError = false; + + if (this.ended) { return false; } + _mode = (mode === ~~mode) ? mode : ((mode === true) ? c.Z_FINISH : c.Z_NO_FLUSH); + + // Convert data if needed + if (typeof data === 'string') { + // Only binary strings can be decompressed on practice + strm.input = strings.binstring2buf(data); + } else if (toString.call(data) === '[object ArrayBuffer]') { + strm.input = new Uint8Array(data); + } else { + strm.input = data; + } + + strm.next_in = 0; + strm.avail_in = strm.input.length; + + do { + if (strm.avail_out === 0) { + strm.output = new utils.Buf8(chunkSize); + strm.next_out = 0; + strm.avail_out = chunkSize; + } + + status = zlib_inflate.inflate(strm, c.Z_NO_FLUSH); /* no bad return value */ + + if (status === c.Z_NEED_DICT && dictionary) { + status = zlib_inflate.inflateSetDictionary(this.strm, dictionary); + } + + if (status === c.Z_BUF_ERROR && allowBufError === true) { + status = c.Z_OK; + allowBufError = false; + } + + if (status !== c.Z_STREAM_END && status !== c.Z_OK) { + this.onEnd(status); + this.ended = true; + return false; + } + + if (strm.next_out) { + if (strm.avail_out === 0 || status === c.Z_STREAM_END || (strm.avail_in === 0 && (_mode === c.Z_FINISH || _mode === c.Z_SYNC_FLUSH))) { + + if (this.options.to === 'string') { + + next_out_utf8 = strings.utf8border(strm.output, strm.next_out); + + tail = strm.next_out - next_out_utf8; + utf8str = strings.buf2string(strm.output, next_out_utf8); + + // move tail + strm.next_out = tail; + strm.avail_out = chunkSize - tail; + if (tail) { utils.arraySet(strm.output, strm.output, next_out_utf8, tail, 0); } + + this.onData(utf8str); + + } else { + this.onData(utils.shrinkBuf(strm.output, strm.next_out)); + } + } + } + + // When no more input data, we should check that internal inflate buffers + // are flushed. The only way to do it when avail_out = 0 - run one more + // inflate pass. But if output data not exists, inflate return Z_BUF_ERROR. + // Here we set flag to process this error properly. + // + // NOTE. Deflate does not return error in this case and does not needs such + // logic. + if (strm.avail_in === 0 && strm.avail_out === 0) { + allowBufError = true; + } + + } while ((strm.avail_in > 0 || strm.avail_out === 0) && status !== c.Z_STREAM_END); + + if (status === c.Z_STREAM_END) { + _mode = c.Z_FINISH; + } + + // Finalize on the last chunk. + if (_mode === c.Z_FINISH) { + status = zlib_inflate.inflateEnd(this.strm); + this.onEnd(status); + this.ended = true; + return status === c.Z_OK; + } + + // callback interim results if Z_SYNC_FLUSH. + if (_mode === c.Z_SYNC_FLUSH) { + this.onEnd(c.Z_OK); + strm.avail_out = 0; + return true; + } + + return true; +}; + + +/** + * Inflate#onData(chunk) -> Void + * - chunk (Uint8Array|Array|String): output data. Type of array depends + * on js engine support. When string output requested, each chunk + * will be string. + * + * By default, stores data blocks in `chunks[]` property and glue + * those in `onEnd`. Override this handler, if you need another behaviour. + **/ +Inflate.prototype.onData = function (chunk) { + this.chunks.push(chunk); +}; + + +/** + * Inflate#onEnd(status) -> Void + * - status (Number): inflate status. 0 (Z_OK) on success, + * other if not. + * + * Called either after you tell inflate that the input stream is + * complete (Z_FINISH) or should be flushed (Z_SYNC_FLUSH) + * or if an error happened. By default - join collected chunks, + * free memory and fill `results` / `err` properties. + **/ +Inflate.prototype.onEnd = function (status) { + // On success - join + if (status === c.Z_OK) { + if (this.options.to === 'string') { + // Glue & convert here, until we teach pako to send + // utf8 aligned strings to onData + this.result = this.chunks.join(''); + } else { + this.result = utils.flattenChunks(this.chunks); + } + } + this.chunks = []; + this.err = status; + this.msg = this.strm.msg; +}; + + +/** + * inflate(data[, options]) -> Uint8Array|Array|String + * - data (Uint8Array|Array|String): input data to decompress. + * - options (Object): zlib inflate options. + * + * Decompress `data` with inflate/ungzip and `options`. Autodetect + * format via wrapper header by default. That's why we don't provide + * separate `ungzip` method. + * + * Supported options are: + * + * - windowBits + * + * [http://zlib.net/manual.html#Advanced](http://zlib.net/manual.html#Advanced) + * for more information. + * + * Sugar (options): + * + * - `raw` (Boolean) - say that we work with raw stream, if you don't wish to specify + * negative windowBits implicitly. + * - `to` (String) - if equal to 'string', then result will be converted + * from utf8 to utf16 (javascript) string. When string output requested, + * chunk length can differ from `chunkSize`, depending on content. + * + * + * ##### Example: + * + * ```javascript + * var pako = require('pako') + * , input = pako.deflate([1,2,3,4,5,6,7,8,9]) + * , output; + * + * try { + * output = pako.inflate(input); + * } catch (err) + * console.log(err); + * } + * ``` + **/ +function inflate(input, options) { + var inflator = new Inflate(options); + + inflator.push(input, true); + + // That will never happens, if you don't cheat with options :) + if (inflator.err) { throw inflator.msg || msg[inflator.err]; } + + return inflator.result; +} + + +/** + * inflateRaw(data[, options]) -> Uint8Array|Array|String + * - data (Uint8Array|Array|String): input data to decompress. + * - options (Object): zlib inflate options. + * + * The same as [[inflate]], but creates raw data, without wrapper + * (header and adler32 crc). + **/ +function inflateRaw(input, options) { + options = options || {}; + options.raw = true; + return inflate(input, options); +} + + +/** + * ungzip(data[, options]) -> Uint8Array|Array|String + * - data (Uint8Array|Array|String): input data to decompress. + * - options (Object): zlib inflate options. + * + * Just shortcut to [[inflate]], because it autodetects format + * by header.content. Done for convenience. + **/ + + +exports.Inflate = Inflate; +exports.inflate = inflate; +exports.inflateRaw = inflateRaw; +exports.ungzip = inflate; |