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hi-ucs/node_modules/pako/lib/zlib/deflate.js

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2022-12-16 09:31:38 +08:00
'use strict';
// (C) 1995-2013 Jean-loup Gailly and Mark Adler
// (C) 2014-2017 Vitaly Puzrin and Andrey Tupitsin
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would be
// appreciated but is not required.
// 2. Altered source versions must be plainly marked as such, and must not be
// misrepresented as being the original software.
// 3. This notice may not be removed or altered from any source distribution.
const { _tr_init, _tr_stored_block, _tr_flush_block, _tr_tally, _tr_align } = require('./trees');
const adler32 = require('./adler32');
const crc32 = require('./crc32');
const msg = require('./messages');
/* Public constants ==========================================================*/
/* ===========================================================================*/
const {
Z_NO_FLUSH, Z_PARTIAL_FLUSH, Z_FULL_FLUSH, Z_FINISH, Z_BLOCK,
Z_OK, Z_STREAM_END, Z_STREAM_ERROR, Z_DATA_ERROR, Z_BUF_ERROR,
Z_DEFAULT_COMPRESSION,
Z_FILTERED, Z_HUFFMAN_ONLY, Z_RLE, Z_FIXED, Z_DEFAULT_STRATEGY,
Z_UNKNOWN,
Z_DEFLATED
} = require('./constants');
/*============================================================================*/
const MAX_MEM_LEVEL = 9;
/* Maximum value for memLevel in deflateInit2 */
const MAX_WBITS = 15;
/* 32K LZ77 window */
const DEF_MEM_LEVEL = 8;
const LENGTH_CODES = 29;
/* number of length codes, not counting the special END_BLOCK code */
const LITERALS = 256;
/* number of literal bytes 0..255 */
const L_CODES = LITERALS + 1 + LENGTH_CODES;
/* number of Literal or Length codes, including the END_BLOCK code */
const D_CODES = 30;
/* number of distance codes */
const BL_CODES = 19;
/* number of codes used to transfer the bit lengths */
const HEAP_SIZE = 2 * L_CODES + 1;
/* maximum heap size */
const MAX_BITS = 15;
/* All codes must not exceed MAX_BITS bits */
const MIN_MATCH = 3;
const MAX_MATCH = 258;
const MIN_LOOKAHEAD = (MAX_MATCH + MIN_MATCH + 1);
const PRESET_DICT = 0x20;
const INIT_STATE = 42; /* zlib header -> BUSY_STATE */
//#ifdef GZIP
const GZIP_STATE = 57; /* gzip header -> BUSY_STATE | EXTRA_STATE */
//#endif
const EXTRA_STATE = 69; /* gzip extra block -> NAME_STATE */
const NAME_STATE = 73; /* gzip file name -> COMMENT_STATE */
const COMMENT_STATE = 91; /* gzip comment -> HCRC_STATE */
const HCRC_STATE = 103; /* gzip header CRC -> BUSY_STATE */
const BUSY_STATE = 113; /* deflate -> FINISH_STATE */
const FINISH_STATE = 666; /* stream complete */
const BS_NEED_MORE = 1; /* block not completed, need more input or more output */
const BS_BLOCK_DONE = 2; /* block flush performed */
const BS_FINISH_STARTED = 3; /* finish started, need only more output at next deflate */
const BS_FINISH_DONE = 4; /* finish done, accept no more input or output */
const OS_CODE = 0x03; // Unix :) . Don't detect, use this default.
const err = (strm, errorCode) => {
strm.msg = msg[errorCode];
return errorCode;
};
const rank = (f) => {
return ((f) * 2) - ((f) > 4 ? 9 : 0);
};
const zero = (buf) => {
let len = buf.length; while (--len >= 0) { buf[len] = 0; }
};
/* ===========================================================================
* Slide the hash table when sliding the window down (could be avoided with 32
* bit values at the expense of memory usage). We slide even when level == 0 to
* keep the hash table consistent if we switch back to level > 0 later.
*/
const slide_hash = (s) => {
let n, m;
let p;
let wsize = s.w_size;
n = s.hash_size;
p = n;
do {
m = s.head[--p];
s.head[p] = (m >= wsize ? m - wsize : 0);
} while (--n);
n = wsize;
//#ifndef FASTEST
p = n;
do {
m = s.prev[--p];
s.prev[p] = (m >= wsize ? m - wsize : 0);
/* If n is not on any hash chain, prev[n] is garbage but
* its value will never be used.
*/
} while (--n);
//#endif
};
/* eslint-disable new-cap */
let HASH_ZLIB = (s, prev, data) => ((prev << s.hash_shift) ^ data) & s.hash_mask;
// This hash causes less collisions, https://github.com/nodeca/pako/issues/135
// But breaks binary compatibility
//let HASH_FAST = (s, prev, data) => ((prev << 8) + (prev >> 8) + (data << 4)) & s.hash_mask;
let HASH = HASH_ZLIB;
/* =========================================================================
* Flush as much pending output as possible. All deflate() output, except for
* some deflate_stored() output, goes through this function so some
* applications may wish to modify it to avoid allocating a large
* strm->next_out buffer and copying into it. (See also read_buf()).
*/
const flush_pending = (strm) => {
const s = strm.state;
//_tr_flush_bits(s);
let len = s.pending;
if (len > strm.avail_out) {
len = strm.avail_out;
}
if (len === 0) { return; }
strm.output.set(s.pending_buf.subarray(s.pending_out, s.pending_out + len), strm.next_out);
strm.next_out += len;
s.pending_out += len;
strm.total_out += len;
strm.avail_out -= len;
s.pending -= len;
if (s.pending === 0) {
s.pending_out = 0;
}
};
const flush_block_only = (s, last) => {
_tr_flush_block(s, (s.block_start >= 0 ? s.block_start : -1), s.strstart - s.block_start, last);
s.block_start = s.strstart;
flush_pending(s.strm);
};
const put_byte = (s, b) => {
s.pending_buf[s.pending++] = b;
};
/* =========================================================================
* Put a short in the pending buffer. The 16-bit value is put in MSB order.
* IN assertion: the stream state is correct and there is enough room in
* pending_buf.
*/
const putShortMSB = (s, b) => {
// put_byte(s, (Byte)(b >> 8));
// put_byte(s, (Byte)(b & 0xff));
s.pending_buf[s.pending++] = (b >>> 8) & 0xff;
s.pending_buf[s.pending++] = b & 0xff;
};
/* ===========================================================================
* Read a new buffer from the current input stream, update the adler32
* and total number of bytes read. All deflate() input goes through
* this function so some applications may wish to modify it to avoid
* allocating a large strm->input buffer and copying from it.
* (See also flush_pending()).
*/
const read_buf = (strm, buf, start, size) => {
let len = strm.avail_in;
if (len > size) { len = size; }
if (len === 0) { return 0; }
strm.avail_in -= len;
// zmemcpy(buf, strm->next_in, len);
buf.set(strm.input.subarray(strm.next_in, strm.next_in + len), start);
if (strm.state.wrap === 1) {
strm.adler = adler32(strm.adler, buf, len, start);
}
else if (strm.state.wrap === 2) {
strm.adler = crc32(strm.adler, buf, len, start);
}
strm.next_in += len;
strm.total_in += len;
return len;
};
/* ===========================================================================
* Set match_start to the longest match starting at the given string and
* return its length. Matches shorter or equal to prev_length are discarded,
* in which case the result is equal to prev_length and match_start is
* garbage.
* IN assertions: cur_match is the head of the hash chain for the current
* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
* OUT assertion: the match length is not greater than s->lookahead.
*/
const longest_match = (s, cur_match) => {
let chain_length = s.max_chain_length; /* max hash chain length */
let scan = s.strstart; /* current string */
let match; /* matched string */
let len; /* length of current match */
let best_len = s.prev_length; /* best match length so far */
let nice_match = s.nice_match; /* stop if match long enough */
const limit = (s.strstart > (s.w_size - MIN_LOOKAHEAD)) ?
s.strstart - (s.w_size - MIN_LOOKAHEAD) : 0/*NIL*/;
const _win = s.window; // shortcut
const wmask = s.w_mask;
const prev = s.prev;
/* Stop when cur_match becomes <= limit. To simplify the code,
* we prevent matches with the string of window index 0.
*/
const strend = s.strstart + MAX_MATCH;
let scan_end1 = _win[scan + best_len - 1];
let scan_end = _win[scan + best_len];
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
* It is easy to get rid of this optimization if necessary.
*/
// Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
/* Do not waste too much time if we already have a good match: */
if (s.prev_length >= s.good_match) {
chain_length >>= 2;
}
/* Do not look for matches beyond the end of the input. This is necessary
* to make deflate deterministic.
*/
if (nice_match > s.lookahead) { nice_match = s.lookahead; }
// Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
do {
// Assert(cur_match < s->strstart, "no future");
match = cur_match;
/* Skip to next match if the match length cannot increase
* or if the match length is less than 2. Note that the checks below
* for insufficient lookahead only occur occasionally for performance
* reasons. Therefore uninitialized memory will be accessed, and
* conditional jumps will be made that depend on those values.
* However the length of the match is limited to the lookahead, so
* the output of deflate is not affected by the uninitialized values.
*/
if (_win[match + best_len] !== scan_end ||
_win[match + best_len - 1] !== scan_end1 ||
_win[match] !== _win[scan] ||
_win[++match] !== _win[scan + 1]) {
continue;
}
/* The check at best_len-1 can be removed because it will be made
* again later. (This heuristic is not always a win.)
* It is not necessary to compare scan[2] and match[2] since they
* are always equal when the other bytes match, given that
* the hash keys are equal and that HASH_BITS >= 8.
*/
scan += 2;
match++;
// Assert(*scan == *match, "match[2]?");
/* We check for insufficient lookahead only every 8th comparison;
* the 256th check will be made at strstart+258.
*/
do {
/*jshint noempty:false*/
} while (_win[++scan] === _win[++match] && _win[++scan] === _win[++match] &&
_win[++scan] === _win[++match] && _win[++scan] === _win[++match] &&
_win[++scan] === _win[++match] && _win[++scan] === _win[++match] &&
_win[++scan] === _win[++match] && _win[++scan] === _win[++match] &&
scan < strend);
// Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
len = MAX_MATCH - (strend - scan);
scan = strend - MAX_MATCH;
if (len > best_len) {
s.match_start = cur_match;
best_len = len;
if (len >= nice_match) {
break;
}
scan_end1 = _win[scan + best_len - 1];
scan_end = _win[scan + best_len];
}
} while ((cur_match = prev[cur_match & wmask]) > limit && --chain_length !== 0);
if (best_len <= s.lookahead) {
return best_len;
}
return s.lookahead;
};
/* ===========================================================================
* Fill the window when the lookahead becomes insufficient.
* Updates strstart and lookahead.
*
* IN assertion: lookahead < MIN_LOOKAHEAD
* OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
* At least one byte has been read, or avail_in == 0; reads are
* performed for at least two bytes (required for the zip translate_eol
* option -- not supported here).
*/
const fill_window = (s) => {
const _w_size = s.w_size;
let n, more, str;
//Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
do {
more = s.window_size - s.lookahead - s.strstart;
// JS ints have 32 bit, block below not needed
/* Deal with !@#$% 64K limit: */
//if (sizeof(int) <= 2) {
// if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
// more = wsize;
//
// } else if (more == (unsigned)(-1)) {
// /* Very unlikely, but possible on 16 bit machine if
// * strstart == 0 && lookahead == 1 (input done a byte at time)
// */
// more--;
// }
//}
/* If the window is almost full and there is insufficient lookahead,
* move the upper half to the lower one to make room in the upper half.
*/
if (s.strstart >= _w_size + (_w_size - MIN_LOOKAHEAD)) {
s.window.set(s.window.subarray(_w_size, _w_size + _w_size - more), 0);
s.match_start -= _w_size;
s.strstart -= _w_size;
/* we now have strstart >= MAX_DIST */
s.block_start -= _w_size;
if (s.insert > s.strstart) {
s.insert = s.strstart;
}
slide_hash(s);
more += _w_size;
}
if (s.strm.avail_in === 0) {
break;
}
/* If there was no sliding:
* strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
* more == window_size - lookahead - strstart
* => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
* => more >= window_size - 2*WSIZE + 2
* In the BIG_MEM or MMAP case (not yet supported),
* window_size == input_size + MIN_LOOKAHEAD &&
* strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
* Otherwise, window_size == 2*WSIZE so more >= 2.
* If there was sliding, more >= WSIZE. So in all cases, more >= 2.
*/
//Assert(more >= 2, "more < 2");
n = read_buf(s.strm, s.window, s.strstart + s.lookahead, more);
s.lookahead += n;
/* Initialize the hash value now that we have some input: */
if (s.lookahead + s.insert >= MIN_MATCH) {
str = s.strstart - s.insert;
s.ins_h = s.window[str];
/* UPDATE_HASH(s, s->ins_h, s->window[str + 1]); */
s.ins_h = HASH(s, s.ins_h, s.window[str + 1]);
//#if MIN_MATCH != 3
// Call update_hash() MIN_MATCH-3 more times
//#endif
while (s.insert) {
/* UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); */
s.ins_h = HASH(s, s.ins_h, s.window[str + MIN_MATCH - 1]);
s.prev[str & s.w_mask] = s.head[s.ins_h];
s.head[s.ins_h] = str;
str++;
s.insert--;
if (s.lookahead + s.insert < MIN_MATCH) {
break;
}
}
}
/* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
* but this is not important since only literal bytes will be emitted.
*/
} while (s.lookahead < MIN_LOOKAHEAD && s.strm.avail_in !== 0);
/* If the WIN_INIT bytes after the end of the current data have never been
* written, then zero those bytes in order to avoid memory check reports of
* the use of uninitialized (or uninitialised as Julian writes) bytes by
* the longest match routines. Update the high water mark for the next
* time through here. WIN_INIT is set to MAX_MATCH since the longest match
* routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
*/
// if (s.high_water < s.window_size) {
// const curr = s.strstart + s.lookahead;
// let init = 0;
//
// if (s.high_water < curr) {
// /* Previous high water mark below current data -- zero WIN_INIT
// * bytes or up to end of window, whichever is less.
// */
// init = s.window_size - curr;
// if (init > WIN_INIT)
// init = WIN_INIT;
// zmemzero(s->window + curr, (unsigned)init);
// s->high_water = curr + init;
// }
// else if (s->high_water < (ulg)curr + WIN_INIT) {
// /* High water mark at or above current data, but below current data
// * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
// * to end of window, whichever is less.
// */
// init = (ulg)curr + WIN_INIT - s->high_water;
// if (init > s->window_size - s->high_water)
// init = s->window_size - s->high_water;
// zmemzero(s->window + s->high_water, (unsigned)init);
// s->high_water += init;
// }
// }
//
// Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
// "not enough room for search");
};
/* ===========================================================================
* Copy without compression as much as possible from the input stream, return
* the current block state.
*
* In case deflateParams() is used to later switch to a non-zero compression
* level, s->matches (otherwise unused when storing) keeps track of the number
* of hash table slides to perform. If s->matches is 1, then one hash table
* slide will be done when switching. If s->matches is 2, the maximum value
* allowed here, then the hash table will be cleared, since two or more slides
* is the same as a clear.
*
* deflate_stored() is written to minimize the number of times an input byte is
* copied. It is most efficient with large input and output buffers, which
* maximizes the opportunites to have a single copy from next_in to next_out.
*/
const deflate_stored = (s, flush) => {
/* Smallest worthy block size when not flushing or finishing. By default
* this is 32K. This can be as small as 507 bytes for memLevel == 1. For
* large input and output buffers, the stored block size will be larger.
*/
let min_block = s.pending_buf_size - 5 > s.w_size ? s.w_size : s.pending_buf_size - 5;
/* Copy as many min_block or larger stored blocks directly to next_out as
* possible. If flushing, copy the remaining available input to next_out as
* stored blocks, if there is enough space.
*/
let len, left, have, last = 0;
let used = s.strm.avail_in;
do {
/* Set len to the maximum size block that we can copy directly with the
* available input data and output space. Set left to how much of that
* would be copied from what's left in the window.
*/
len = 65535/* MAX_STORED */; /* maximum deflate stored block length */
have = (s.bi_valid + 42) >> 3; /* number of header bytes */
if (s.strm.avail_out < have) { /* need room for header */
break;
}
/* maximum stored block length that will fit in avail_out: */
have = s.strm.avail_out - have;
left = s.strstart - s.block_start; /* bytes left in window */
if (len > left + s.strm.avail_in) {
len = left + s.strm.avail_in; /* limit len to the input */
}
if (len > have) {
len = have; /* limit len to the output */
}
/* If the stored block would be less than min_block in length, or if
* unable to copy all of the available input when flushing, then try
* copying to the window and the pending buffer instead. Also don't
* write an empty block when flushing -- deflate() does that.
*/
if (len < min_block && ((len === 0 && flush !== Z_FINISH) ||
flush === Z_NO_FLUSH ||
len !== left + s.strm.avail_in)) {
break;
}
/* Make a dummy stored block in pending to get the header bytes,
* including any pending bits. This also updates the debugging counts.
*/
last = flush === Z_FINISH && len === left + s.strm.avail_in ? 1 : 0;
_tr_stored_block(s, 0, 0, last);
/* Replace the lengths in the dummy stored block with len. */
s.pending_buf[s.pending - 4] = len;
s.pending_buf[s.pending - 3] = len >> 8;
s.pending_buf[s.pending - 2] = ~len;
s.pending_buf[s.pending - 1] = ~len >> 8;
/* Write the stored block header bytes. */
flush_pending(s.strm);
//#ifdef ZLIB_DEBUG
// /* Update debugging counts for the data about to be copied. */
// s->compressed_len += len << 3;
// s->bits_sent += len << 3;
//#endif
/* Copy uncompressed bytes from the window to next_out. */
if (left) {
if (left > len) {
left = len;
}
//zmemcpy(s->strm->next_out, s->window + s->block_start, left);
s.strm.output.set(s.window.subarray(s.block_start, s.block_start + left), s.strm.next_out);
s.strm.next_out += left;
s.strm.avail_out -= left;
s.strm.total_out += left;
s.block_start += left;
len -= left;
}
/* Copy uncompressed bytes directly from next_in to next_out, updating
* the check value.
*/
if (len) {
read_buf(s.strm, s.strm.output, s.strm.next_out, len);
s.strm.next_out += len;
s.strm.avail_out -= len;
s.strm.total_out += len;
}
} while (last === 0);
/* Update the sliding window with the last s->w_size bytes of the copied
* data, or append all of the copied data to the existing window if less
* than s->w_size bytes were copied. Also update the number of bytes to
* insert in the hash tables, in the event that deflateParams() switches to
* a non-zero compression level.
*/
used -= s.strm.avail_in; /* number of input bytes directly copied */
if (used) {
/* If any input was used, then no unused input remains in the window,
* therefore s->block_start == s->strstart.
*/
if (used >= s.w_size) { /* supplant the previous history */
s.matches = 2; /* clear hash */
//zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
s.window.set(s.strm.input.subarray(s.strm.next_in - s.w_size, s.strm.next_in), 0);
s.strstart = s.w_size;
s.insert = s.strstart;
}
else {
if (s.window_size - s.strstart <= used) {
/* Slide the window down. */
s.strstart -= s.w_size;
//zmemcpy(s->window, s->window + s->w_size, s->strstart);
s.window.set(s.window.subarray(s.w_size, s.w_size + s.strstart), 0);
if (s.matches < 2) {
s.matches++; /* add a pending slide_hash() */
}
if (s.insert > s.strstart) {
s.insert = s.strstart;
}
}
//zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
s.window.set(s.strm.input.subarray(s.strm.next_in - used, s.strm.next_in), s.strstart);
s.strstart += used;
s.insert += used > s.w_size - s.insert ? s.w_size - s.insert : used;
}
s.block_start = s.strstart;
}
if (s.high_water < s.strstart) {
s.high_water = s.strstart;
}
/* If the last block was written to next_out, then done. */
if (last) {
return BS_FINISH_DONE;
}
/* If flushing and all input has been consumed, then done. */
if (flush !== Z_NO_FLUSH && flush !== Z_FINISH &&
s.strm.avail_in === 0 && s.strstart === s.block_start) {
return BS_BLOCK_DONE;
}
/* Fill the window with any remaining input. */
have = s.window_size - s.strstart;
if (s.strm.avail_in > have && s.block_start >= s.w_size) {
/* Slide the window down. */
s.block_start -= s.w_size;
s.strstart -= s.w_size;
//zmemcpy(s->window, s->window + s->w_size, s->strstart);
s.window.set(s.window.subarray(s.w_size, s.w_size + s.strstart), 0);
if (s.matches < 2) {
s.matches++; /* add a pending slide_hash() */
}
have += s.w_size; /* more space now */
if (s.insert > s.strstart) {
s.insert = s.strstart;
}
}
if (have > s.strm.avail_in) {
have = s.strm.avail_in;
}
if (have) {
read_buf(s.strm, s.window, s.strstart, have);
s.strstart += have;
s.insert += have > s.w_size - s.insert ? s.w_size - s.insert : have;
}
if (s.high_water < s.strstart) {
s.high_water = s.strstart;
}
/* There was not enough avail_out to write a complete worthy or flushed
* stored block to next_out. Write a stored block to pending instead, if we
* have enough input for a worthy block, or if flushing and there is enough
* room for the remaining input as a stored block in the pending buffer.
*/
have = (s.bi_valid + 42) >> 3; /* number of header bytes */
/* maximum stored block length that will fit in pending: */
have = s.pending_buf_size - have > 65535/* MAX_STORED */ ? 65535/* MAX_STORED */ : s.pending_buf_size - have;
min_block = have > s.w_size ? s.w_size : have;
left = s.strstart - s.block_start;
if (left >= min_block ||
((left || flush === Z_FINISH) && flush !== Z_NO_FLUSH &&
s.strm.avail_in === 0 && left <= have)) {
len = left > have ? have : left;
last = flush === Z_FINISH && s.strm.avail_in === 0 &&
len === left ? 1 : 0;
_tr_stored_block(s, s.block_start, len, last);
s.block_start += len;
flush_pending(s.strm);
}
/* We've done all we can with the available input and output. */
return last ? BS_FINISH_STARTED : BS_NEED_MORE;
};
/* ===========================================================================
* Compress as much as possible from the input stream, return the current
* block state.
* This function does not perform lazy evaluation of matches and inserts
* new strings in the dictionary only for unmatched strings or for short
* matches. It is used only for the fast compression options.
*/
const deflate_fast = (s, flush) => {
let hash_head; /* head of the hash chain */
let bflush; /* set if current block must be flushed */
for (;;) {
/* Make sure that we always have enough lookahead, except
* at the end of the input file. We need MAX_MATCH bytes
* for the next match, plus MIN_MATCH bytes to insert the
* string following the next match.
*/
if (s.lookahead < MIN_LOOKAHEAD) {
fill_window(s);
if (s.lookahead < MIN_LOOKAHEAD && flush === Z_NO_FLUSH) {
return BS_NEED_MORE;
}
if (s.lookahead === 0) {
break; /* flush the current block */
}
}
/* Insert the string window[strstart .. strstart+2] in the
* dictionary, and set hash_head to the head of the hash chain:
*/
hash_head = 0/*NIL*/;
if (s.lookahead >= MIN_MATCH) {
/*** INSERT_STRING(s, s.strstart, hash_head); ***/
s.ins_h = HASH(s, s.ins_h, s.window[s.strstart + MIN_MATCH - 1]);
hash_head = s.prev[s.strstart & s.w_mask] = s.head[s.ins_h];
s.head[s.ins_h] = s.strstart;
/***/
}
/* Find the longest match, discarding those <= prev_length.
* At this point we have always match_length < MIN_MATCH
*/
if (hash_head !== 0/*NIL*/ && ((s.strstart - hash_head) <= (s.w_size - MIN_LOOKAHEAD))) {
/* To simplify the code, we prevent matches with the string
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
*/
s.match_length = longest_match(s, hash_head);
/* longest_match() sets match_start */
}
if (s.match_length >= MIN_MATCH) {
// check_match(s, s.strstart, s.match_start, s.match_length); // for debug only
/*** _tr_tally_dist(s, s.strstart - s.match_start,
s.match_length - MIN_MATCH, bflush); ***/
bflush = _tr_tally(s, s.strstart - s.match_start, s.match_length - MIN_MATCH);
s.lookahead -= s.match_length;
/* Insert new strings in the hash table only if the match length
* is not too large. This saves time but degrades compression.
*/
if (s.match_length <= s.max_lazy_match/*max_insert_length*/ && s.lookahead >= MIN_MATCH) {
s.match_length--; /* string at strstart already in table */
do {
s.strstart++;
/*** INSERT_STRING(s, s.strstart, hash_head); ***/
s.ins_h = HASH(s, s.ins_h, s.window[s.strstart + MIN_MATCH - 1]);
hash_head = s.prev[s.strstart & s.w_mask] = s.head[s.ins_h];
s.head[s.ins_h] = s.strstart;
/***/
/* strstart never exceeds WSIZE-MAX_MATCH, so there are
* always MIN_MATCH bytes ahead.
*/
} while (--s.match_length !== 0);
s.strstart++;
} else
{
s.strstart += s.match_length;
s.match_length = 0;
s.ins_h = s.window[s.strstart];
/* UPDATE_HASH(s, s.ins_h, s.window[s.strstart+1]); */
s.ins_h = HASH(s, s.ins_h, s.window[s.strstart + 1]);
//#if MIN_MATCH != 3
// Call UPDATE_HASH() MIN_MATCH-3 more times
//#endif
/* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
* matter since it will be recomputed at next deflate call.
*/
}
} else {
/* No match, output a literal byte */
//Tracevv((stderr,"%c", s.window[s.strstart]));
/*** _tr_tally_lit(s, s.window[s.strstart], bflush); ***/
bflush = _tr_tally(s, 0, s.window[s.strstart]);
s.lookahead--;
s.strstart++;
}
if (bflush) {
/*** FLUSH_BLOCK(s, 0); ***/
flush_block_only(s, false);
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
/***/
}
}
s.insert = ((s.strstart < (MIN_MATCH - 1)) ? s.strstart : MIN_MATCH - 1);
if (flush === Z_FINISH) {
/*** FLUSH_BLOCK(s, 1); ***/
flush_block_only(s, true);
if (s.strm.avail_out === 0) {
return BS_FINISH_STARTED;
}
/***/
return BS_FINISH_DONE;
}
if (s.sym_next) {
/*** FLUSH_BLOCK(s, 0); ***/
flush_block_only(s, false);
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
/***/
}
return BS_BLOCK_DONE;
};
/* ===========================================================================
* Same as above, but achieves better compression. We use a lazy
* evaluation for matches: a match is finally adopted only if there is
* no better match at the next window position.
*/
const deflate_slow = (s, flush) => {
let hash_head; /* head of hash chain */
let bflush; /* set if current block must be flushed */
let max_insert;
/* Process the input block. */
for (;;) {
/* Make sure that we always have enough lookahead, except
* at the end of the input file. We need MAX_MATCH bytes
* for the next match, plus MIN_MATCH bytes to insert the
* string following the next match.
*/
if (s.lookahead < MIN_LOOKAHEAD) {
fill_window(s);
if (s.lookahead < MIN_LOOKAHEAD && flush === Z_NO_FLUSH) {
return BS_NEED_MORE;
}
if (s.lookahead === 0) { break; } /* flush the current block */
}
/* Insert the string window[strstart .. strstart+2] in the
* dictionary, and set hash_head to the head of the hash chain:
*/
hash_head = 0/*NIL*/;
if (s.lookahead >= MIN_MATCH) {
/*** INSERT_STRING(s, s.strstart, hash_head); ***/
s.ins_h = HASH(s, s.ins_h, s.window[s.strstart + MIN_MATCH - 1]);
hash_head = s.prev[s.strstart & s.w_mask] = s.head[s.ins_h];
s.head[s.ins_h] = s.strstart;
/***/
}
/* Find the longest match, discarding those <= prev_length.
*/
s.prev_length = s.match_length;
s.prev_match = s.match_start;
s.match_length = MIN_MATCH - 1;
if (hash_head !== 0/*NIL*/ && s.prev_length < s.max_lazy_match &&
s.strstart - hash_head <= (s.w_size - MIN_LOOKAHEAD)/*MAX_DIST(s)*/) {
/* To simplify the code, we prevent matches with the string
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
*/
s.match_length = longest_match(s, hash_head);
/* longest_match() sets match_start */
if (s.match_length <= 5 &&
(s.strategy === Z_FILTERED || (s.match_length === MIN_MATCH && s.strstart - s.match_start > 4096/*TOO_FAR*/))) {
/* If prev_match is also MIN_MATCH, match_start is garbage
* but we will ignore the current match anyway.
*/
s.match_length = MIN_MATCH - 1;
}
}
/* If there was a match at the previous step and the current
* match is not better, output the previous match:
*/
if (s.prev_length >= MIN_MATCH && s.match_length <= s.prev_length) {
max_insert = s.strstart + s.lookahead - MIN_MATCH;
/* Do not insert strings in hash table beyond this. */
//check_match(s, s.strstart-1, s.prev_match, s.prev_length);
/***_tr_tally_dist(s, s.strstart - 1 - s.prev_match,
s.prev_length - MIN_MATCH, bflush);***/
bflush = _tr_tally(s, s.strstart - 1 - s.prev_match, s.prev_length - MIN_MATCH);
/* Insert in hash table all strings up to the end of the match.
* strstart-1 and strstart are already inserted. If there is not
* enough lookahead, the last two strings are not inserted in
* the hash table.
*/
s.lookahead -= s.prev_length - 1;
s.prev_length -= 2;
do {
if (++s.strstart <= max_insert) {
/*** INSERT_STRING(s, s.strstart, hash_head); ***/
s.ins_h = HASH(s, s.ins_h, s.window[s.strstart + MIN_MATCH - 1]);
hash_head = s.prev[s.strstart & s.w_mask] = s.head[s.ins_h];
s.head[s.ins_h] = s.strstart;
/***/
}
} while (--s.prev_length !== 0);
s.match_available = 0;
s.match_length = MIN_MATCH - 1;
s.strstart++;
if (bflush) {
/*** FLUSH_BLOCK(s, 0); ***/
flush_block_only(s, false);
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
/***/
}
} else if (s.match_available) {
/* If there was no match at the previous position, output a
* single literal. If there was a match but the current match
* is longer, truncate the previous match to a single literal.
*/
//Tracevv((stderr,"%c", s->window[s->strstart-1]));
/*** _tr_tally_lit(s, s.window[s.strstart-1], bflush); ***/
bflush = _tr_tally(s, 0, s.window[s.strstart - 1]);
if (bflush) {
/*** FLUSH_BLOCK_ONLY(s, 0) ***/
flush_block_only(s, false);
/***/
}
s.strstart++;
s.lookahead--;
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
} else {
/* There is no previous match to compare with, wait for
* the next step to decide.
*/
s.match_available = 1;
s.strstart++;
s.lookahead--;
}
}
//Assert (flush != Z_NO_FLUSH, "no flush?");
if (s.match_available) {
//Tracevv((stderr,"%c", s->window[s->strstart-1]));
/*** _tr_tally_lit(s, s.window[s.strstart-1], bflush); ***/
bflush = _tr_tally(s, 0, s.window[s.strstart - 1]);
s.match_available = 0;
}
s.insert = s.strstart < MIN_MATCH - 1 ? s.strstart : MIN_MATCH - 1;
if (flush === Z_FINISH) {
/*** FLUSH_BLOCK(s, 1); ***/
flush_block_only(s, true);
if (s.strm.avail_out === 0) {
return BS_FINISH_STARTED;
}
/***/
return BS_FINISH_DONE;
}
if (s.sym_next) {
/*** FLUSH_BLOCK(s, 0); ***/
flush_block_only(s, false);
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
/***/
}
return BS_BLOCK_DONE;
};
/* ===========================================================================
* For Z_RLE, simply look for runs of bytes, generate matches only of distance
* one. Do not maintain a hash table. (It will be regenerated if this run of
* deflate switches away from Z_RLE.)
*/
const deflate_rle = (s, flush) => {
let bflush; /* set if current block must be flushed */
let prev; /* byte at distance one to match */
let scan, strend; /* scan goes up to strend for length of run */
const _win = s.window;
for (;;) {
/* Make sure that we always have enough lookahead, except
* at the end of the input file. We need MAX_MATCH bytes
* for the longest run, plus one for the unrolled loop.
*/
if (s.lookahead <= MAX_MATCH) {
fill_window(s);
if (s.lookahead <= MAX_MATCH && flush === Z_NO_FLUSH) {
return BS_NEED_MORE;
}
if (s.lookahead === 0) { break; } /* flush the current block */
}
/* See how many times the previous byte repeats */
s.match_length = 0;
if (s.lookahead >= MIN_MATCH && s.strstart > 0) {
scan = s.strstart - 1;
prev = _win[scan];
if (prev === _win[++scan] && prev === _win[++scan] && prev === _win[++scan]) {
strend = s.strstart + MAX_MATCH;
do {
/*jshint noempty:false*/
} while (prev === _win[++scan] && prev === _win[++scan] &&
prev === _win[++scan] && prev === _win[++scan] &&
prev === _win[++scan] && prev === _win[++scan] &&
prev === _win[++scan] && prev === _win[++scan] &&
scan < strend);
s.match_length = MAX_MATCH - (strend - scan);
if (s.match_length > s.lookahead) {
s.match_length = s.lookahead;
}
}
//Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
}
/* Emit match if have run of MIN_MATCH or longer, else emit literal */
if (s.match_length >= MIN_MATCH) {
//check_match(s, s.strstart, s.strstart - 1, s.match_length);
/*** _tr_tally_dist(s, 1, s.match_length - MIN_MATCH, bflush); ***/
bflush = _tr_tally(s, 1, s.match_length - MIN_MATCH);
s.lookahead -= s.match_length;
s.strstart += s.match_length;
s.match_length = 0;
} else {
/* No match, output a literal byte */
//Tracevv((stderr,"%c", s->window[s->strstart]));
/*** _tr_tally_lit(s, s.window[s.strstart], bflush); ***/
bflush = _tr_tally(s, 0, s.window[s.strstart]);
s.lookahead--;
s.strstart++;
}
if (bflush) {
/*** FLUSH_BLOCK(s, 0); ***/
flush_block_only(s, false);
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
/***/
}
}
s.insert = 0;
if (flush === Z_FINISH) {
/*** FLUSH_BLOCK(s, 1); ***/
flush_block_only(s, true);
if (s.strm.avail_out === 0) {
return BS_FINISH_STARTED;
}
/***/
return BS_FINISH_DONE;
}
if (s.sym_next) {
/*** FLUSH_BLOCK(s, 0); ***/
flush_block_only(s, false);
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
/***/
}
return BS_BLOCK_DONE;
};
/* ===========================================================================
* For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
* (It will be regenerated if this run of deflate switches away from Huffman.)
*/
const deflate_huff = (s, flush) => {
let bflush; /* set if current block must be flushed */
for (;;) {
/* Make sure that we have a literal to write. */
if (s.lookahead === 0) {
fill_window(s);
if (s.lookahead === 0) {
if (flush === Z_NO_FLUSH) {
return BS_NEED_MORE;
}
break; /* flush the current block */
}
}
/* Output a literal byte */
s.match_length = 0;
//Tracevv((stderr,"%c", s->window[s->strstart]));
/*** _tr_tally_lit(s, s.window[s.strstart], bflush); ***/
bflush = _tr_tally(s, 0, s.window[s.strstart]);
s.lookahead--;
s.strstart++;
if (bflush) {
/*** FLUSH_BLOCK(s, 0); ***/
flush_block_only(s, false);
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
/***/
}
}
s.insert = 0;
if (flush === Z_FINISH) {
/*** FLUSH_BLOCK(s, 1); ***/
flush_block_only(s, true);
if (s.strm.avail_out === 0) {
return BS_FINISH_STARTED;
}
/***/
return BS_FINISH_DONE;
}
if (s.sym_next) {
/*** FLUSH_BLOCK(s, 0); ***/
flush_block_only(s, false);
if (s.strm.avail_out === 0) {
return BS_NEED_MORE;
}
/***/
}
return BS_BLOCK_DONE;
};
/* Values for max_lazy_match, good_match and max_chain_length, depending on
* the desired pack level (0..9). The values given below have been tuned to
* exclude worst case performance for pathological files. Better values may be
* found for specific files.
*/
function Config(good_length, max_lazy, nice_length, max_chain, func) {
this.good_length = good_length;
this.max_lazy = max_lazy;
this.nice_length = nice_length;
this.max_chain = max_chain;
this.func = func;
}
const configuration_table = [
/* good lazy nice chain */
new Config(0, 0, 0, 0, deflate_stored), /* 0 store only */
new Config(4, 4, 8, 4, deflate_fast), /* 1 max speed, no lazy matches */
new Config(4, 5, 16, 8, deflate_fast), /* 2 */
new Config(4, 6, 32, 32, deflate_fast), /* 3 */
new Config(4, 4, 16, 16, deflate_slow), /* 4 lazy matches */
new Config(8, 16, 32, 32, deflate_slow), /* 5 */
new Config(8, 16, 128, 128, deflate_slow), /* 6 */
new Config(8, 32, 128, 256, deflate_slow), /* 7 */
new Config(32, 128, 258, 1024, deflate_slow), /* 8 */
new Config(32, 258, 258, 4096, deflate_slow) /* 9 max compression */
];
/* ===========================================================================
* Initialize the "longest match" routines for a new zlib stream
*/
const lm_init = (s) => {
s.window_size = 2 * s.w_size;
/*** CLEAR_HASH(s); ***/
zero(s.head); // Fill with NIL (= 0);
/* Set the default configuration parameters:
*/
s.max_lazy_match = configuration_table[s.level].max_lazy;
s.good_match = configuration_table[s.level].good_length;
s.nice_match = configuration_table[s.level].nice_length;
s.max_chain_length = configuration_table[s.level].max_chain;
s.strstart = 0;
s.block_start = 0;
s.lookahead = 0;
s.insert = 0;
s.match_length = s.prev_length = MIN_MATCH - 1;
s.match_available = 0;
s.ins_h = 0;
};
function DeflateState() {
this.strm = null; /* pointer back to this zlib stream */
this.status = 0; /* as the name implies */
this.pending_buf = null; /* output still pending */
this.pending_buf_size = 0; /* size of pending_buf */
this.pending_out = 0; /* next pending byte to output to the stream */
this.pending = 0; /* nb of bytes in the pending buffer */
this.wrap = 0; /* bit 0 true for zlib, bit 1 true for gzip */
this.gzhead = null; /* gzip header information to write */
this.gzindex = 0; /* where in extra, name, or comment */
this.method = Z_DEFLATED; /* can only be DEFLATED */
this.last_flush = -1; /* value of flush param for previous deflate call */
this.w_size = 0; /* LZ77 window size (32K by default) */
this.w_bits = 0; /* log2(w_size) (8..16) */
this.w_mask = 0; /* w_size - 1 */
this.window = null;
/* Sliding window. Input bytes are read into the second half of the window,
* and move to the first half later to keep a dictionary of at least wSize
* bytes. With this organization, matches are limited to a distance of
* wSize-MAX_MATCH bytes, but this ensures that IO is always
* performed with a length multiple of the block size.
*/
this.window_size = 0;
/* Actual size of window: 2*wSize, except when the user input buffer
* is directly used as sliding window.
*/
this.prev = null;
/* Link to older string with same hash index. To limit the size of this
* array to 64K, this link is maintained only for the last 32K strings.
* An index in this array is thus a window index modulo 32K.
*/
this.head = null; /* Heads of the hash chains or NIL. */
this.ins_h = 0; /* hash index of string to be inserted */
this.hash_size = 0; /* number of elements in hash table */
this.hash_bits = 0; /* log2(hash_size) */
this.hash_mask = 0; /* hash_size-1 */
this.hash_shift = 0;
/* Number of bits by which ins_h must be shifted at each input
* step. It must be such that after MIN_MATCH steps, the oldest
* byte no longer takes part in the hash key, that is:
* hash_shift * MIN_MATCH >= hash_bits
*/
this.block_start = 0;
/* Window position at the beginning of the current output block. Gets
* negative when the window is moved backwards.
*/
this.match_length = 0; /* length of best match */
this.prev_match = 0; /* previous match */
this.match_available = 0; /* set if previous match exists */
this.strstart = 0; /* start of string to insert */
this.match_start = 0; /* start of matching string */
this.lookahead = 0; /* number of valid bytes ahead in window */
this.prev_length = 0;
/* Length of the best match at previous step. Matches not greater than this
* are discarded. This is used in the lazy match evaluation.
*/
this.max_chain_length = 0;
/* To speed up deflation, hash chains are never searched beyond this
* length. A higher limit improves compression ratio but degrades the
* speed.
*/
this.max_lazy_match = 0;
/* Attempt to find a better match only when the current match is strictly
* smaller than this value. This mechanism is used only for compression
* levels >= 4.
*/
// That's alias to max_lazy_match, don't use directly
//this.max_insert_length = 0;
/* Insert new strings in the hash table only if the match length is not
* greater than this length. This saves time but degrades compression.
* max_insert_length is used only for compression levels <= 3.
*/
this.level = 0; /* compression level (1..9) */
this.strategy = 0; /* favor or force Huffman coding*/
this.good_match = 0;
/* Use a faster search when the previous match is longer than this */
this.nice_match = 0; /* Stop searching when current match exceeds this */
/* used by trees.c: */
/* Didn't use ct_data typedef below to suppress compiler warning */
// struct ct_data_s dyn_ltree[HEAP_SIZE]; /* literal and length tree */
// struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
// struct ct_data_s bl_tree[2*BL_CODES+1]; /* Huffman tree for bit lengths */
// Use flat array of DOUBLE size, with interleaved fata,
// because JS does not support effective
this.dyn_ltree = new Uint16Array(HEAP_SIZE * 2);
this.dyn_dtree = new Uint16Array((2 * D_CODES + 1) * 2);
this.bl_tree = new Uint16Array((2 * BL_CODES + 1) * 2);
zero(this.dyn_ltree);
zero(this.dyn_dtree);
zero(this.bl_tree);
this.l_desc = null; /* desc. for literal tree */
this.d_desc = null; /* desc. for distance tree */
this.bl_desc = null; /* desc. for bit length tree */
//ush bl_count[MAX_BITS+1];
this.bl_count = new Uint16Array(MAX_BITS + 1);
/* number of codes at each bit length for an optimal tree */
//int heap[2*L_CODES+1]; /* heap used to build the Huffman trees */
this.heap = new Uint16Array(2 * L_CODES + 1); /* heap used to build the Huffman trees */
zero(this.heap);
this.heap_len = 0; /* number of elements in the heap */
this.heap_max = 0; /* element of largest frequency */
/* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
* The same heap array is used to build all trees.
*/
this.depth = new Uint16Array(2 * L_CODES + 1); //uch depth[2*L_CODES+1];
zero(this.depth);
/* Depth of each subtree used as tie breaker for trees of equal frequency
*/
this.sym_buf = 0; /* buffer for distances and literals/lengths */
this.lit_bufsize = 0;
/* Size of match buffer for literals/lengths. There are 4 reasons for
* limiting lit_bufsize to 64K:
* - frequencies can be kept in 16 bit counters
* - if compression is not successful for the first block, all input
* data is still in the window so we can still emit a stored block even
* when input comes from standard input. (This can also be done for
* all blocks if lit_bufsize is not greater than 32K.)
* - if compression is not successful for a file smaller than 64K, we can
* even emit a stored file instead of a stored block (saving 5 bytes).
* This is applicable only for zip (not gzip or zlib).
* - creating new Huffman trees less frequently may not provide fast
* adaptation to changes in the input data statistics. (Take for
* example a binary file with poorly compressible code followed by
* a highly compressible string table.) Smaller buffer sizes give
* fast adaptation but have of course the overhead of transmitting
* trees more frequently.
* - I can't count above 4
*/
this.sym_next = 0; /* running index in sym_buf */
this.sym_end = 0; /* symbol table full when sym_next reaches this */
this.opt_len = 0; /* bit length of current block with optimal trees */
this.static_len = 0; /* bit length of current block with static trees */
this.matches = 0; /* number of string matches in current block */
this.insert = 0; /* bytes at end of window left to insert */
this.bi_buf = 0;
/* Output buffer. bits are inserted starting at the bottom (least
* significant bits).
*/
this.bi_valid = 0;
/* Number of valid bits in bi_buf. All bits above the last valid bit
* are always zero.
*/
// Used for window memory init. We safely ignore it for JS. That makes
// sense only for pointers and memory check tools.
//this.high_water = 0;
/* High water mark offset in window for initialized bytes -- bytes above
* this are set to zero in order to avoid memory check warnings when
* longest match routines access bytes past the input. This is then
* updated to the new high water mark.
*/
}
/* =========================================================================
* Check for a valid deflate stream state. Return 0 if ok, 1 if not.
*/
const deflateStateCheck = (strm) => {
if (!strm) {
return 1;
}
const s = strm.state;
if (!s || s.strm !== strm || (s.status !== INIT_STATE &&
//#ifdef GZIP
s.status !== GZIP_STATE &&
//#endif
s.status !== EXTRA_STATE &&
s.status !== NAME_STATE &&
s.status !== COMMENT_STATE &&
s.status !== HCRC_STATE &&
s.status !== BUSY_STATE &&
s.status !== FINISH_STATE)) {
return 1;
}
return 0;
};
const deflateResetKeep = (strm) => {
if (deflateStateCheck(strm)) {
return err(strm, Z_STREAM_ERROR);
}
strm.total_in = strm.total_out = 0;
strm.data_type = Z_UNKNOWN;
const s = strm.state;
s.pending = 0;
s.pending_out = 0;
if (s.wrap < 0) {
s.wrap = -s.wrap;
/* was made negative by deflate(..., Z_FINISH); */
}
s.status =
//#ifdef GZIP
s.wrap === 2 ? GZIP_STATE :
//#endif
s.wrap ? INIT_STATE : BUSY_STATE;
strm.adler = (s.wrap === 2) ?
0 // crc32(0, Z_NULL, 0)
:
1; // adler32(0, Z_NULL, 0)
s.last_flush = -2;
_tr_init(s);
return Z_OK;
};
const deflateReset = (strm) => {
const ret = deflateResetKeep(strm);
if (ret === Z_OK) {
lm_init(strm.state);
}
return ret;
};
const deflateSetHeader = (strm, head) => {
if (deflateStateCheck(strm) || strm.state.wrap !== 2) {
return Z_STREAM_ERROR;
}
strm.state.gzhead = head;
return Z_OK;
};
const deflateInit2 = (strm, level, method, windowBits, memLevel, strategy) => {
if (!strm) { // === Z_NULL
return Z_STREAM_ERROR;
}
let wrap = 1;
if (level === Z_DEFAULT_COMPRESSION) {
level = 6;
}
if (windowBits < 0) { /* suppress zlib wrapper */
wrap = 0;
windowBits = -windowBits;
}
else if (windowBits > 15) {
wrap = 2; /* write gzip wrapper instead */
windowBits -= 16;
}
if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method !== Z_DEFLATED ||
windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
strategy < 0 || strategy > Z_FIXED || (windowBits === 8 && wrap !== 1)) {
return err(strm, Z_STREAM_ERROR);
}
if (windowBits === 8) {
windowBits = 9;
}
/* until 256-byte window bug fixed */
const s = new DeflateState();
strm.state = s;
s.strm = strm;
s.status = INIT_STATE; /* to pass state test in deflateReset() */
s.wrap = wrap;
s.gzhead = null;
s.w_bits = windowBits;
s.w_size = 1 << s.w_bits;
s.w_mask = s.w_size - 1;
s.hash_bits = memLevel + 7;
s.hash_size = 1 << s.hash_bits;
s.hash_mask = s.hash_size - 1;
s.hash_shift = ~~((s.hash_bits + MIN_MATCH - 1) / MIN_MATCH);
s.window = new Uint8Array(s.w_size * 2);
s.head = new Uint16Array(s.hash_size);
s.prev = new Uint16Array(s.w_size);
// Don't need mem init magic for JS.
//s.high_water = 0; /* nothing written to s->window yet */
s.lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
/* We overlay pending_buf and sym_buf. This works since the average size
* for length/distance pairs over any compressed block is assured to be 31
* bits or less.
*
* Analysis: The longest fixed codes are a length code of 8 bits plus 5
* extra bits, for lengths 131 to 257. The longest fixed distance codes are
* 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest
* possible fixed-codes length/distance pair is then 31 bits total.
*
* sym_buf starts one-fourth of the way into pending_buf. So there are
* three bytes in sym_buf for every four bytes in pending_buf. Each symbol
* in sym_buf is three bytes -- two for the distance and one for the
* literal/length. As each symbol is consumed, the pointer to the next
* sym_buf value to read moves forward three bytes. From that symbol, up to
* 31 bits are written to pending_buf. The closest the written pending_buf
* bits gets to the next sym_buf symbol to read is just before the last
* code is written. At that time, 31*(n-2) bits have been written, just
* after 24*(n-2) bits have been consumed from sym_buf. sym_buf starts at
* 8*n bits into pending_buf. (Note that the symbol buffer fills when n-1
* symbols are written.) The closest the writing gets to what is unread is
* then n+14 bits. Here n is lit_bufsize, which is 16384 by default, and
* can range from 128 to 32768.
*
* Therefore, at a minimum, there are 142 bits of space between what is
* written and what is read in the overlain buffers, so the symbols cannot
* be overwritten by the compressed data. That space is actually 139 bits,
* due to the three-bit fixed-code block header.
*
* That covers the case where either Z_FIXED is specified, forcing fixed
* codes, or when the use of fixed codes is chosen, because that choice
* results in a smaller compressed block than dynamic codes. That latter
* condition then assures that the above analysis also covers all dynamic
* blocks. A dynamic-code block will only be chosen to be emitted if it has
* fewer bits than a fixed-code block would for the same set of symbols.
* Therefore its average symbol length is assured to be less than 31. So
* the compressed data for a dynamic block also cannot overwrite the
* symbols from which it is being constructed.
*/
s.pending_buf_size = s.lit_bufsize * 4;
s.pending_buf = new Uint8Array(s.pending_buf_size);
// It is offset from `s.pending_buf` (size is `s.lit_bufsize * 2`)
//s->sym_buf = s->pending_buf + s->lit_bufsize;
s.sym_buf = s.lit_bufsize;
//s->sym_end = (s->lit_bufsize - 1) * 3;
s.sym_end = (s.lit_bufsize - 1) * 3;
/* We avoid equality with lit_bufsize*3 because of wraparound at 64K
* on 16 bit machines and because stored blocks are restricted to
* 64K-1 bytes.
*/
s.level = level;
s.strategy = strategy;
s.method = method;
return deflateReset(strm);
};
const deflateInit = (strm, level) => {
return deflateInit2(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
};
/* ========================================================================= */
const deflate = (strm, flush) => {
if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) {
return strm ? err(strm, Z_STREAM_ERROR) : Z_STREAM_ERROR;
}
const s = strm.state;
if (!strm.output ||
(strm.avail_in !== 0 && !strm.input) ||
(s.status === FINISH_STATE && flush !== Z_FINISH)) {
return err(strm, (strm.avail_out === 0) ? Z_BUF_ERROR : Z_STREAM_ERROR);
}
const old_flush = s.last_flush;
s.last_flush = flush;
/* Flush as much pending output as possible */
if (s.pending !== 0) {
flush_pending(strm);
if (strm.avail_out === 0) {
/* Since avail_out is 0, deflate will be called again with
* more output space, but possibly with both pending and
* avail_in equal to zero. There won't be anything to do,
* but this is not an error situation so make sure we
* return OK instead of BUF_ERROR at next call of deflate:
*/
s.last_flush = -1;
return Z_OK;
}
/* Make sure there is something to do and avoid duplicate consecutive
* flushes. For repeated and useless calls with Z_FINISH, we keep
* returning Z_STREAM_END instead of Z_BUF_ERROR.
*/
} else if (strm.avail_in === 0 && rank(flush) <= rank(old_flush) &&
flush !== Z_FINISH) {
return err(strm, Z_BUF_ERROR);
}
/* User must not provide more input after the first FINISH: */
if (s.status === FINISH_STATE && strm.avail_in !== 0) {
return err(strm, Z_BUF_ERROR);
}
/* Write the header */
if (s.status === INIT_STATE && s.wrap === 0) {
s.status = BUSY_STATE;
}
if (s.status === INIT_STATE) {
/* zlib header */
let header = (Z_DEFLATED + ((s.w_bits - 8) << 4)) << 8;
let level_flags = -1;
if (s.strategy >= Z_HUFFMAN_ONLY || s.level < 2) {
level_flags = 0;
} else if (s.level < 6) {
level_flags = 1;
} else if (s.level === 6) {
level_flags = 2;
} else {
level_flags = 3;
}
header |= (level_flags << 6);
if (s.strstart !== 0) { header |= PRESET_DICT; }
header += 31 - (header % 31);
putShortMSB(s, header);
/* Save the adler32 of the preset dictionary: */
if (s.strstart !== 0) {
putShortMSB(s, strm.adler >>> 16);
putShortMSB(s, strm.adler & 0xffff);
}
strm.adler = 1; // adler32(0L, Z_NULL, 0);
s.status = BUSY_STATE;
/* Compression must start with an empty pending buffer */
flush_pending(strm);
if (s.pending !== 0) {
s.last_flush = -1;
return Z_OK;
}
}
//#ifdef GZIP
if (s.status === GZIP_STATE) {
/* gzip header */
strm.adler = 0; //crc32(0L, Z_NULL, 0);
put_byte(s, 31);
put_byte(s, 139);
put_byte(s, 8);
if (!s.gzhead) { // s->gzhead == Z_NULL
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, s.level === 9 ? 2 :
(s.strategy >= Z_HUFFMAN_ONLY || s.level < 2 ?
4 : 0));
put_byte(s, OS_CODE);
s.status = BUSY_STATE;
/* Compression must start with an empty pending buffer */
flush_pending(strm);
if (s.pending !== 0) {
s.last_flush = -1;
return Z_OK;
}
}
else {
put_byte(s, (s.gzhead.text ? 1 : 0) +
(s.gzhead.hcrc ? 2 : 0) +
(!s.gzhead.extra ? 0 : 4) +
(!s.gzhead.name ? 0 : 8) +
(!s.gzhead.comment ? 0 : 16)
);
put_byte(s, s.gzhead.time & 0xff);
put_byte(s, (s.gzhead.time >> 8) & 0xff);
put_byte(s, (s.gzhead.time >> 16) & 0xff);
put_byte(s, (s.gzhead.time >> 24) & 0xff);
put_byte(s, s.level === 9 ? 2 :
(s.strategy >= Z_HUFFMAN_ONLY || s.level < 2 ?
4 : 0));
put_byte(s, s.gzhead.os & 0xff);
if (s.gzhead.extra && s.gzhead.extra.length) {
put_byte(s, s.gzhead.extra.length & 0xff);
put_byte(s, (s.gzhead.extra.length >> 8) & 0xff);
}
if (s.gzhead.hcrc) {
strm.adler = crc32(strm.adler, s.pending_buf, s.pending, 0);
}
s.gzindex = 0;
s.status = EXTRA_STATE;
}
}
if (s.status === EXTRA_STATE) {
if (s.gzhead.extra/* != Z_NULL*/) {
let beg = s.pending; /* start of bytes to update crc */
let left = (s.gzhead.extra.length & 0xffff) - s.gzindex;
while (s.pending + left > s.pending_buf_size) {
let copy = s.pending_buf_size - s.pending;
// zmemcpy(s.pending_buf + s.pending,
// s.gzhead.extra + s.gzindex, copy);
s.pending_buf.set(s.gzhead.extra.subarray(s.gzindex, s.gzindex + copy), s.pending);
s.pending = s.pending_buf_size;
//--- HCRC_UPDATE(beg) ---//
if (s.gzhead.hcrc && s.pending > beg) {
strm.adler = crc32(strm.adler, s.pending_buf, s.pending - beg, beg);
}
//---//
s.gzindex += copy;
flush_pending(strm);
if (s.pending !== 0) {
s.last_flush = -1;
return Z_OK;
}
beg = 0;
left -= copy;
}
// JS specific: s.gzhead.extra may be TypedArray or Array for backward compatibility
// TypedArray.slice and TypedArray.from don't exist in IE10-IE11
let gzhead_extra = new Uint8Array(s.gzhead.extra);
// zmemcpy(s->pending_buf + s->pending,
// s->gzhead->extra + s->gzindex, left);
s.pending_buf.set(gzhead_extra.subarray(s.gzindex, s.gzindex + left), s.pending);
s.pending += left;
//--- HCRC_UPDATE(beg) ---//
if (s.gzhead.hcrc && s.pending > beg) {
strm.adler = crc32(strm.adler, s.pending_buf, s.pending - beg, beg);
}
//---//
s.gzindex = 0;
}
s.status = NAME_STATE;
}
if (s.status === NAME_STATE) {
if (s.gzhead.name/* != Z_NULL*/) {
let beg = s.pending; /* start of bytes to update crc */
let val;
do {
if (s.pending === s.pending_buf_size) {
//--- HCRC_UPDATE(beg) ---//
if (s.gzhead.hcrc && s.pending > beg) {
strm.adler = crc32(strm.adler, s.pending_buf, s.pending - beg, beg);
}
//---//
flush_pending(strm);
if (s.pending !== 0) {
s.last_flush = -1;
return Z_OK;
}
beg = 0;
}
// JS specific: little magic to add zero terminator to end of string
if (s.gzindex < s.gzhead.name.length) {
val = s.gzhead.name.charCodeAt(s.gzindex++) & 0xff;
} else {
val = 0;
}
put_byte(s, val);
} while (val !== 0);
//--- HCRC_UPDATE(beg) ---//
if (s.gzhead.hcrc && s.pending > beg) {
strm.adler = crc32(strm.adler, s.pending_buf, s.pending - beg, beg);
}
//---//
s.gzindex = 0;
}
s.status = COMMENT_STATE;
}
if (s.status === COMMENT_STATE) {
if (s.gzhead.comment/* != Z_NULL*/) {
let beg = s.pending; /* start of bytes to update crc */
let val;
do {
if (s.pending === s.pending_buf_size) {
//--- HCRC_UPDATE(beg) ---//
if (s.gzhead.hcrc && s.pending > beg) {
strm.adler = crc32(strm.adler, s.pending_buf, s.pending - beg, beg);
}
//---//
flush_pending(strm);
if (s.pending !== 0) {
s.last_flush = -1;
return Z_OK;
}
beg = 0;
}
// JS specific: little magic to add zero terminator to end of string
if (s.gzindex < s.gzhead.comment.length) {
val = s.gzhead.comment.charCodeAt(s.gzindex++) & 0xff;
} else {
val = 0;
}
put_byte(s, val);
} while (val !== 0);
//--- HCRC_UPDATE(beg) ---//
if (s.gzhead.hcrc && s.pending > beg) {
strm.adler = crc32(strm.adler, s.pending_buf, s.pending - beg, beg);
}
//---//
}
s.status = HCRC_STATE;
}
if (s.status === HCRC_STATE) {
if (s.gzhead.hcrc) {
if (s.pending + 2 > s.pending_buf_size) {
flush_pending(strm);
if (s.pending !== 0) {
s.last_flush = -1;
return Z_OK;
}
}
put_byte(s, strm.adler & 0xff);
put_byte(s, (strm.adler >> 8) & 0xff);
strm.adler = 0; //crc32(0L, Z_NULL, 0);
}
s.status = BUSY_STATE;
/* Compression must start with an empty pending buffer */
flush_pending(strm);
if (s.pending !== 0) {
s.last_flush = -1;
return Z_OK;
}
}
//#endif
/* Start a new block or continue the current one.
*/
if (strm.avail_in !== 0 || s.lookahead !== 0 ||
(flush !== Z_NO_FLUSH && s.status !== FINISH_STATE)) {
let bstate = s.level === 0 ? deflate_stored(s, flush) :
s.strategy === Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
s.strategy === Z_RLE ? deflate_rle(s, flush) :
configuration_table[s.level].func(s, flush);
if (bstate === BS_FINISH_STARTED || bstate === BS_FINISH_DONE) {
s.status = FINISH_STATE;
}
if (bstate === BS_NEED_MORE || bstate === BS_FINISH_STARTED) {
if (strm.avail_out === 0) {
s.last_flush = -1;
/* avoid BUF_ERROR next call, see above */
}
return Z_OK;
/* If flush != Z_NO_FLUSH && avail_out == 0, the next call
* of deflate should use the same flush parameter to make sure
* that the flush is complete. So we don't have to output an
* empty block here, this will be done at next call. This also
* ensures that for a very small output buffer, we emit at most
* one empty block.
*/
}
if (bstate === BS_BLOCK_DONE) {
if (flush === Z_PARTIAL_FLUSH) {
_tr_align(s);
}
else if (flush !== Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
_tr_stored_block(s, 0, 0, false);
/* For a full flush, this empty block will be recognized
* as a special marker by inflate_sync().
*/
if (flush === Z_FULL_FLUSH) {
/*** CLEAR_HASH(s); ***/ /* forget history */
zero(s.head); // Fill with NIL (= 0);
if (s.lookahead === 0) {
s.strstart = 0;
s.block_start = 0;
s.insert = 0;
}
}
}
flush_pending(strm);
if (strm.avail_out === 0) {
s.last_flush = -1; /* avoid BUF_ERROR at next call, see above */
return Z_OK;
}
}
}
if (flush !== Z_FINISH) { return Z_OK; }
if (s.wrap <= 0) { return Z_STREAM_END; }
/* Write the trailer */
if (s.wrap === 2) {
put_byte(s, strm.adler & 0xff);
put_byte(s, (strm.adler >> 8) & 0xff);
put_byte(s, (strm.adler >> 16) & 0xff);
put_byte(s, (strm.adler >> 24) & 0xff);
put_byte(s, strm.total_in & 0xff);
put_byte(s, (strm.total_in >> 8) & 0xff);
put_byte(s, (strm.total_in >> 16) & 0xff);
put_byte(s, (strm.total_in >> 24) & 0xff);
}
else
{
putShortMSB(s, strm.adler >>> 16);
putShortMSB(s, strm.adler & 0xffff);
}
flush_pending(strm);
/* If avail_out is zero, the application will call deflate again
* to flush the rest.
*/
if (s.wrap > 0) { s.wrap = -s.wrap; }
/* write the trailer only once! */
return s.pending !== 0 ? Z_OK : Z_STREAM_END;
};
const deflateEnd = (strm) => {
if (deflateStateCheck(strm)) {
return Z_STREAM_ERROR;
}
const status = strm.state.status;
strm.state = null;
return status === BUSY_STATE ? err(strm, Z_DATA_ERROR) : Z_OK;
};
/* =========================================================================
* Initializes the compression dictionary from the given byte
* sequence without producing any compressed output.
*/
const deflateSetDictionary = (strm, dictionary) => {
let dictLength = dictionary.length;
if (deflateStateCheck(strm)) {
return Z_STREAM_ERROR;
}
const s = strm.state;
const wrap = s.wrap;
if (wrap === 2 || (wrap === 1 && s.status !== INIT_STATE) || s.lookahead) {
return Z_STREAM_ERROR;
}
/* when using zlib wrappers, compute Adler-32 for provided dictionary */
if (wrap === 1) {
/* adler32(strm->adler, dictionary, dictLength); */
strm.adler = adler32(strm.adler, dictionary, dictLength, 0);
}
s.wrap = 0; /* avoid computing Adler-32 in read_buf */
/* if dictionary would fill window, just replace the history */
if (dictLength >= s.w_size) {
if (wrap === 0) { /* already empty otherwise */
/*** CLEAR_HASH(s); ***/
zero(s.head); // Fill with NIL (= 0);
s.strstart = 0;
s.block_start = 0;
s.insert = 0;
}
/* use the tail */
// dictionary = dictionary.slice(dictLength - s.w_size);
let tmpDict = new Uint8Array(s.w_size);
tmpDict.set(dictionary.subarray(dictLength - s.w_size, dictLength), 0);
dictionary = tmpDict;
dictLength = s.w_size;
}
/* insert dictionary into window and hash */
const avail = strm.avail_in;
const next = strm.next_in;
const input = strm.input;
strm.avail_in = dictLength;
strm.next_in = 0;
strm.input = dictionary;
fill_window(s);
while (s.lookahead >= MIN_MATCH) {
let str = s.strstart;
let n = s.lookahead - (MIN_MATCH - 1);
do {
/* UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); */
s.ins_h = HASH(s, s.ins_h, s.window[str + MIN_MATCH - 1]);
s.prev[str & s.w_mask] = s.head[s.ins_h];
s.head[s.ins_h] = str;
str++;
} while (--n);
s.strstart = str;
s.lookahead = MIN_MATCH - 1;
fill_window(s);
}
s.strstart += s.lookahead;
s.block_start = s.strstart;
s.insert = s.lookahead;
s.lookahead = 0;
s.match_length = s.prev_length = MIN_MATCH - 1;
s.match_available = 0;
strm.next_in = next;
strm.input = input;
strm.avail_in = avail;
s.wrap = wrap;
return Z_OK;
};
module.exports.deflateInit = deflateInit;
module.exports.deflateInit2 = deflateInit2;
module.exports.deflateReset = deflateReset;
module.exports.deflateResetKeep = deflateResetKeep;
module.exports.deflateSetHeader = deflateSetHeader;
module.exports.deflate = deflate;
module.exports.deflateEnd = deflateEnd;
module.exports.deflateSetDictionary = deflateSetDictionary;
module.exports.deflateInfo = 'pako deflate (from Nodeca project)';
/* Not implemented
module.exports.deflateBound = deflateBound;
module.exports.deflateCopy = deflateCopy;
module.exports.deflateGetDictionary = deflateGetDictionary;
module.exports.deflateParams = deflateParams;
module.exports.deflatePending = deflatePending;
module.exports.deflatePrime = deflatePrime;
module.exports.deflateTune = deflateTune;
*/