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Diffstat (limited to 'school/node_modules/pako/lib/zlib/trees.js')
| -rw-r--r-- | school/node_modules/pako/lib/zlib/trees.js | 1222 |
1 files changed, 0 insertions, 1222 deletions
diff --git a/school/node_modules/pako/lib/zlib/trees.js b/school/node_modules/pako/lib/zlib/trees.js deleted file mode 100644 index aaf15db..0000000 --- a/school/node_modules/pako/lib/zlib/trees.js +++ /dev/null @@ -1,1222 +0,0 @@ -'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. - -/* eslint-disable space-unary-ops */ - -var utils = require('../utils/common'); - -/* Public constants ==========================================================*/ -/* ===========================================================================*/ - - -//var Z_FILTERED = 1; -//var Z_HUFFMAN_ONLY = 2; -//var Z_RLE = 3; -var Z_FIXED = 4; -//var Z_DEFAULT_STRATEGY = 0; - -/* Possible values of the data_type field (though see inflate()) */ -var Z_BINARY = 0; -var Z_TEXT = 1; -//var Z_ASCII = 1; // = Z_TEXT -var Z_UNKNOWN = 2; - -/*============================================================================*/ - - -function zero(buf) { var len = buf.length; while (--len >= 0) { buf[len] = 0; } } - -// From zutil.h - -var STORED_BLOCK = 0; -var STATIC_TREES = 1; -var DYN_TREES = 2; -/* The three kinds of block type */ - -var MIN_MATCH = 3; -var MAX_MATCH = 258; -/* The minimum and maximum match lengths */ - -// From deflate.h -/* =========================================================================== - * Internal compression state. - */ - -var LENGTH_CODES = 29; -/* number of length codes, not counting the special END_BLOCK code */ - -var LITERALS = 256; -/* number of literal bytes 0..255 */ - -var L_CODES = LITERALS + 1 + LENGTH_CODES; -/* number of Literal or Length codes, including the END_BLOCK code */ - -var D_CODES = 30; -/* number of distance codes */ - -var BL_CODES = 19; -/* number of codes used to transfer the bit lengths */ - -var HEAP_SIZE = 2 * L_CODES + 1; -/* maximum heap size */ - -var MAX_BITS = 15; -/* All codes must not exceed MAX_BITS bits */ - -var Buf_size = 16; -/* size of bit buffer in bi_buf */ - - -/* =========================================================================== - * Constants - */ - -var MAX_BL_BITS = 7; -/* Bit length codes must not exceed MAX_BL_BITS bits */ - -var END_BLOCK = 256; -/* end of block literal code */ - -var REP_3_6 = 16; -/* repeat previous bit length 3-6 times (2 bits of repeat count) */ - -var REPZ_3_10 = 17; -/* repeat a zero length 3-10 times (3 bits of repeat count) */ - -var REPZ_11_138 = 18; -/* repeat a zero length 11-138 times (7 bits of repeat count) */ - -/* eslint-disable comma-spacing,array-bracket-spacing */ -var extra_lbits = /* extra bits for each length code */ - [0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0]; - -var extra_dbits = /* extra bits for each distance code */ - [0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13]; - -var extra_blbits = /* extra bits for each bit length code */ - [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7]; - -var bl_order = - [16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15]; -/* eslint-enable comma-spacing,array-bracket-spacing */ - -/* The lengths of the bit length codes are sent in order of decreasing - * probability, to avoid transmitting the lengths for unused bit length codes. - */ - -/* =========================================================================== - * Local data. These are initialized only once. - */ - -// We pre-fill arrays with 0 to avoid uninitialized gaps - -var DIST_CODE_LEN = 512; /* see definition of array dist_code below */ - -// !!!! Use flat array instead of structure, Freq = i*2, Len = i*2+1 -var static_ltree = new Array((L_CODES + 2) * 2); -zero(static_ltree); -/* The static literal tree. Since the bit lengths are imposed, there is no - * need for the L_CODES extra codes used during heap construction. However - * The codes 286 and 287 are needed to build a canonical tree (see _tr_init - * below). - */ - -var static_dtree = new Array(D_CODES * 2); -zero(static_dtree); -/* The static distance tree. (Actually a trivial tree since all codes use - * 5 bits.) - */ - -var _dist_code = new Array(DIST_CODE_LEN); -zero(_dist_code); -/* Distance codes. The first 256 values correspond to the distances - * 3 .. 258, the last 256 values correspond to the top 8 bits of - * the 15 bit distances. - */ - -var _length_code = new Array(MAX_MATCH - MIN_MATCH + 1); -zero(_length_code); -/* length code for each normalized match length (0 == MIN_MATCH) */ - -var base_length = new Array(LENGTH_CODES); -zero(base_length); -/* First normalized length for each code (0 = MIN_MATCH) */ - -var base_dist = new Array(D_CODES); -zero(base_dist); -/* First normalized distance for each code (0 = distance of 1) */ - - -function StaticTreeDesc(static_tree, extra_bits, extra_base, elems, max_length) { - - this.static_tree = static_tree; /* static tree or NULL */ - this.extra_bits = extra_bits; /* extra bits for each code or NULL */ - this.extra_base = extra_base; /* base index for extra_bits */ - this.elems = elems; /* max number of elements in the tree */ - this.max_length = max_length; /* max bit length for the codes */ - - // show if `static_tree` has data or dummy - needed for monomorphic objects - this.has_stree = static_tree && static_tree.length; -} - - -var static_l_desc; -var static_d_desc; -var static_bl_desc; - - -function TreeDesc(dyn_tree, stat_desc) { - this.dyn_tree = dyn_tree; /* the dynamic tree */ - this.max_code = 0; /* largest code with non zero frequency */ - this.stat_desc = stat_desc; /* the corresponding static tree */ -} - - - -function d_code(dist) { - return dist < 256 ? _dist_code[dist] : _dist_code[256 + (dist >>> 7)]; -} - - -/* =========================================================================== - * Output a short LSB first on the stream. - * IN assertion: there is enough room in pendingBuf. - */ -function put_short(s, w) { -// put_byte(s, (uch)((w) & 0xff)); -// put_byte(s, (uch)((ush)(w) >> 8)); - s.pending_buf[s.pending++] = (w) & 0xff; - s.pending_buf[s.pending++] = (w >>> 8) & 0xff; -} - - -/* =========================================================================== - * Send a value on a given number of bits. - * IN assertion: length <= 16 and value fits in length bits. - */ -function send_bits(s, value, length) { - if (s.bi_valid > (Buf_size - length)) { - s.bi_buf |= (value << s.bi_valid) & 0xffff; - put_short(s, s.bi_buf); - s.bi_buf = value >> (Buf_size - s.bi_valid); - s.bi_valid += length - Buf_size; - } else { - s.bi_buf |= (value << s.bi_valid) & 0xffff; - s.bi_valid += length; - } -} - - -function send_code(s, c, tree) { - send_bits(s, tree[c * 2]/*.Code*/, tree[c * 2 + 1]/*.Len*/); -} - - -/* =========================================================================== - * Reverse the first len bits of a code, using straightforward code (a faster - * method would use a table) - * IN assertion: 1 <= len <= 15 - */ -function bi_reverse(code, len) { - var res = 0; - do { - res |= code & 1; - code >>>= 1; - res <<= 1; - } while (--len > 0); - return res >>> 1; -} - - -/* =========================================================================== - * Flush the bit buffer, keeping at most 7 bits in it. - */ -function bi_flush(s) { - if (s.bi_valid === 16) { - put_short(s, s.bi_buf); - s.bi_buf = 0; - s.bi_valid = 0; - - } else if (s.bi_valid >= 8) { - s.pending_buf[s.pending++] = s.bi_buf & 0xff; - s.bi_buf >>= 8; - s.bi_valid -= 8; - } -} - - -/* =========================================================================== - * Compute the optimal bit lengths for a tree and update the total bit length - * for the current block. - * IN assertion: the fields freq and dad are set, heap[heap_max] and - * above are the tree nodes sorted by increasing frequency. - * OUT assertions: the field len is set to the optimal bit length, the - * array bl_count contains the frequencies for each bit length. - * The length opt_len is updated; static_len is also updated if stree is - * not null. - */ -function gen_bitlen(s, desc) -// deflate_state *s; -// tree_desc *desc; /* the tree descriptor */ -{ - var tree = desc.dyn_tree; - var max_code = desc.max_code; - var stree = desc.stat_desc.static_tree; - var has_stree = desc.stat_desc.has_stree; - var extra = desc.stat_desc.extra_bits; - var base = desc.stat_desc.extra_base; - var max_length = desc.stat_desc.max_length; - var h; /* heap index */ - var n, m; /* iterate over the tree elements */ - var bits; /* bit length */ - var xbits; /* extra bits */ - var f; /* frequency */ - var overflow = 0; /* number of elements with bit length too large */ - - for (bits = 0; bits <= MAX_BITS; bits++) { - s.bl_count[bits] = 0; - } - - /* In a first pass, compute the optimal bit lengths (which may - * overflow in the case of the bit length tree). - */ - tree[s.heap[s.heap_max] * 2 + 1]/*.Len*/ = 0; /* root of the heap */ - - for (h = s.heap_max + 1; h < HEAP_SIZE; h++) { - n = s.heap[h]; - bits = tree[tree[n * 2 + 1]/*.Dad*/ * 2 + 1]/*.Len*/ + 1; - if (bits > max_length) { - bits = max_length; - overflow++; - } - tree[n * 2 + 1]/*.Len*/ = bits; - /* We overwrite tree[n].Dad which is no longer needed */ - - if (n > max_code) { continue; } /* not a leaf node */ - - s.bl_count[bits]++; - xbits = 0; - if (n >= base) { - xbits = extra[n - base]; - } - f = tree[n * 2]/*.Freq*/; - s.opt_len += f * (bits + xbits); - if (has_stree) { - s.static_len += f * (stree[n * 2 + 1]/*.Len*/ + xbits); - } - } - if (overflow === 0) { return; } - - // Trace((stderr,"\nbit length overflow\n")); - /* This happens for example on obj2 and pic of the Calgary corpus */ - - /* Find the first bit length which could increase: */ - do { - bits = max_length - 1; - while (s.bl_count[bits] === 0) { bits--; } - s.bl_count[bits]--; /* move one leaf down the tree */ - s.bl_count[bits + 1] += 2; /* move one overflow item as its brother */ - s.bl_count[max_length]--; - /* The brother of the overflow item also moves one step up, - * but this does not affect bl_count[max_length] - */ - overflow -= 2; - } while (overflow > 0); - - /* Now recompute all bit lengths, scanning in increasing frequency. - * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all - * lengths instead of fixing only the wrong ones. This idea is taken - * from 'ar' written by Haruhiko Okumura.) - */ - for (bits = max_length; bits !== 0; bits--) { - n = s.bl_count[bits]; - while (n !== 0) { - m = s.heap[--h]; - if (m > max_code) { continue; } - if (tree[m * 2 + 1]/*.Len*/ !== bits) { - // Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); - s.opt_len += (bits - tree[m * 2 + 1]/*.Len*/) * tree[m * 2]/*.Freq*/; - tree[m * 2 + 1]/*.Len*/ = bits; - } - n--; - } - } -} - - -/* =========================================================================== - * Generate the codes for a given tree and bit counts (which need not be - * optimal). - * IN assertion: the array bl_count contains the bit length statistics for - * the given tree and the field len is set for all tree elements. - * OUT assertion: the field code is set for all tree elements of non - * zero code length. - */ -function gen_codes(tree, max_code, bl_count) -// ct_data *tree; /* the tree to decorate */ -// int max_code; /* largest code with non zero frequency */ -// ushf *bl_count; /* number of codes at each bit length */ -{ - var next_code = new Array(MAX_BITS + 1); /* next code value for each bit length */ - var code = 0; /* running code value */ - var bits; /* bit index */ - var n; /* code index */ - - /* The distribution counts are first used to generate the code values - * without bit reversal. - */ - for (bits = 1; bits <= MAX_BITS; bits++) { - next_code[bits] = code = (code + bl_count[bits - 1]) << 1; - } - /* Check that the bit counts in bl_count are consistent. The last code - * must be all ones. - */ - //Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, - // "inconsistent bit counts"); - //Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); - - for (n = 0; n <= max_code; n++) { - var len = tree[n * 2 + 1]/*.Len*/; - if (len === 0) { continue; } - /* Now reverse the bits */ - tree[n * 2]/*.Code*/ = bi_reverse(next_code[len]++, len); - - //Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", - // n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); - } -} - - -/* =========================================================================== - * Initialize the various 'constant' tables. - */ -function tr_static_init() { - var n; /* iterates over tree elements */ - var bits; /* bit counter */ - var length; /* length value */ - var code; /* code value */ - var dist; /* distance index */ - var bl_count = new Array(MAX_BITS + 1); - /* number of codes at each bit length for an optimal tree */ - - // do check in _tr_init() - //if (static_init_done) return; - - /* For some embedded targets, global variables are not initialized: */ -/*#ifdef NO_INIT_GLOBAL_POINTERS - static_l_desc.static_tree = static_ltree; - static_l_desc.extra_bits = extra_lbits; - static_d_desc.static_tree = static_dtree; - static_d_desc.extra_bits = extra_dbits; - static_bl_desc.extra_bits = extra_blbits; -#endif*/ - - /* Initialize the mapping length (0..255) -> length code (0..28) */ - length = 0; - for (code = 0; code < LENGTH_CODES - 1; code++) { - base_length[code] = length; - for (n = 0; n < (1 << extra_lbits[code]); n++) { - _length_code[length++] = code; - } - } - //Assert (length == 256, "tr_static_init: length != 256"); - /* Note that the length 255 (match length 258) can be represented - * in two different ways: code 284 + 5 bits or code 285, so we - * overwrite length_code[255] to use the best encoding: - */ - _length_code[length - 1] = code; - - /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ - dist = 0; - for (code = 0; code < 16; code++) { - base_dist[code] = dist; - for (n = 0; n < (1 << extra_dbits[code]); n++) { - _dist_code[dist++] = code; - } - } - //Assert (dist == 256, "tr_static_init: dist != 256"); - dist >>= 7; /* from now on, all distances are divided by 128 */ - for (; code < D_CODES; code++) { - base_dist[code] = dist << 7; - for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) { - _dist_code[256 + dist++] = code; - } - } - //Assert (dist == 256, "tr_static_init: 256+dist != 512"); - - /* Construct the codes of the static literal tree */ - for (bits = 0; bits <= MAX_BITS; bits++) { - bl_count[bits] = 0; - } - - n = 0; - while (n <= 143) { - static_ltree[n * 2 + 1]/*.Len*/ = 8; - n++; - bl_count[8]++; - } - while (n <= 255) { - static_ltree[n * 2 + 1]/*.Len*/ = 9; - n++; - bl_count[9]++; - } - while (n <= 279) { - static_ltree[n * 2 + 1]/*.Len*/ = 7; - n++; - bl_count[7]++; - } - while (n <= 287) { - static_ltree[n * 2 + 1]/*.Len*/ = 8; - n++; - bl_count[8]++; - } - /* Codes 286 and 287 do not exist, but we must include them in the - * tree construction to get a canonical Huffman tree (longest code - * all ones) - */ - gen_codes(static_ltree, L_CODES + 1, bl_count); - - /* The static distance tree is trivial: */ - for (n = 0; n < D_CODES; n++) { - static_dtree[n * 2 + 1]/*.Len*/ = 5; - static_dtree[n * 2]/*.Code*/ = bi_reverse(n, 5); - } - - // Now data ready and we can init static trees - static_l_desc = new StaticTreeDesc(static_ltree, extra_lbits, LITERALS + 1, L_CODES, MAX_BITS); - static_d_desc = new StaticTreeDesc(static_dtree, extra_dbits, 0, D_CODES, MAX_BITS); - static_bl_desc = new StaticTreeDesc(new Array(0), extra_blbits, 0, BL_CODES, MAX_BL_BITS); - - //static_init_done = true; -} - - -/* =========================================================================== - * Initialize a new block. - */ -function init_block(s) { - var n; /* iterates over tree elements */ - - /* Initialize the trees. */ - for (n = 0; n < L_CODES; n++) { s.dyn_ltree[n * 2]/*.Freq*/ = 0; } - for (n = 0; n < D_CODES; n++) { s.dyn_dtree[n * 2]/*.Freq*/ = 0; } - for (n = 0; n < BL_CODES; n++) { s.bl_tree[n * 2]/*.Freq*/ = 0; } - - s.dyn_ltree[END_BLOCK * 2]/*.Freq*/ = 1; - s.opt_len = s.static_len = 0; - s.last_lit = s.matches = 0; -} - - -/* =========================================================================== - * Flush the bit buffer and align the output on a byte boundary - */ -function bi_windup(s) -{ - if (s.bi_valid > 8) { - put_short(s, s.bi_buf); - } else if (s.bi_valid > 0) { - //put_byte(s, (Byte)s->bi_buf); - s.pending_buf[s.pending++] = s.bi_buf; - } - s.bi_buf = 0; - s.bi_valid = 0; -} - -/* =========================================================================== - * Copy a stored block, storing first the length and its - * one's complement if requested. - */ -function copy_block(s, buf, len, header) -//DeflateState *s; -//charf *buf; /* the input data */ -//unsigned len; /* its length */ -//int header; /* true if block header must be written */ -{ - bi_windup(s); /* align on byte boundary */ - - if (header) { - put_short(s, len); - put_short(s, ~len); - } -// while (len--) { -// put_byte(s, *buf++); -// } - utils.arraySet(s.pending_buf, s.window, buf, len, s.pending); - s.pending += len; -} - -/* =========================================================================== - * Compares to subtrees, using the tree depth as tie breaker when - * the subtrees have equal frequency. This minimizes the worst case length. - */ -function smaller(tree, n, m, depth) { - var _n2 = n * 2; - var _m2 = m * 2; - return (tree[_n2]/*.Freq*/ < tree[_m2]/*.Freq*/ || - (tree[_n2]/*.Freq*/ === tree[_m2]/*.Freq*/ && depth[n] <= depth[m])); -} - -/* =========================================================================== - * Restore the heap property by moving down the tree starting at node k, - * exchanging a node with the smallest of its two sons if necessary, stopping - * when the heap property is re-established (each father smaller than its - * two sons). - */ -function pqdownheap(s, tree, k) -// deflate_state *s; -// ct_data *tree; /* the tree to restore */ -// int k; /* node to move down */ -{ - var v = s.heap[k]; - var j = k << 1; /* left son of k */ - while (j <= s.heap_len) { - /* Set j to the smallest of the two sons: */ - if (j < s.heap_len && - smaller(tree, s.heap[j + 1], s.heap[j], s.depth)) { - j++; - } - /* Exit if v is smaller than both sons */ - if (smaller(tree, v, s.heap[j], s.depth)) { break; } - - /* Exchange v with the smallest son */ - s.heap[k] = s.heap[j]; - k = j; - - /* And continue down the tree, setting j to the left son of k */ - j <<= 1; - } - s.heap[k] = v; -} - - -// inlined manually -// var SMALLEST = 1; - -/* =========================================================================== - * Send the block data compressed using the given Huffman trees - */ -function compress_block(s, ltree, dtree) -// deflate_state *s; -// const ct_data *ltree; /* literal tree */ -// const ct_data *dtree; /* distance tree */ -{ - var dist; /* distance of matched string */ - var lc; /* match length or unmatched char (if dist == 0) */ - var lx = 0; /* running index in l_buf */ - var code; /* the code to send */ - var extra; /* number of extra bits to send */ - - if (s.last_lit !== 0) { - do { - dist = (s.pending_buf[s.d_buf + lx * 2] << 8) | (s.pending_buf[s.d_buf + lx * 2 + 1]); - lc = s.pending_buf[s.l_buf + lx]; - lx++; - - if (dist === 0) { - send_code(s, lc, ltree); /* send a literal byte */ - //Tracecv(isgraph(lc), (stderr," '%c' ", lc)); - } else { - /* Here, lc is the match length - MIN_MATCH */ - code = _length_code[lc]; - send_code(s, code + LITERALS + 1, ltree); /* send the length code */ - extra = extra_lbits[code]; - if (extra !== 0) { - lc -= base_length[code]; - send_bits(s, lc, extra); /* send the extra length bits */ - } - dist--; /* dist is now the match distance - 1 */ - code = d_code(dist); - //Assert (code < D_CODES, "bad d_code"); - - send_code(s, code, dtree); /* send the distance code */ - extra = extra_dbits[code]; - if (extra !== 0) { - dist -= base_dist[code]; - send_bits(s, dist, extra); /* send the extra distance bits */ - } - } /* literal or match pair ? */ - - /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ - //Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, - // "pendingBuf overflow"); - - } while (lx < s.last_lit); - } - - send_code(s, END_BLOCK, ltree); -} - - -/* =========================================================================== - * Construct one Huffman tree and assigns the code bit strings and lengths. - * Update the total bit length for the current block. - * IN assertion: the field freq is set for all tree elements. - * OUT assertions: the fields len and code are set to the optimal bit length - * and corresponding code. The length opt_len is updated; static_len is - * also updated if stree is not null. The field max_code is set. - */ -function build_tree(s, desc) -// deflate_state *s; -// tree_desc *desc; /* the tree descriptor */ -{ - var tree = desc.dyn_tree; - var stree = desc.stat_desc.static_tree; - var has_stree = desc.stat_desc.has_stree; - var elems = desc.stat_desc.elems; - var n, m; /* iterate over heap elements */ - var max_code = -1; /* largest code with non zero frequency */ - var node; /* new node being created */ - - /* Construct the initial heap, with least frequent element in - * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. - * heap[0] is not used. - */ - s.heap_len = 0; - s.heap_max = HEAP_SIZE; - - for (n = 0; n < elems; n++) { - if (tree[n * 2]/*.Freq*/ !== 0) { - s.heap[++s.heap_len] = max_code = n; - s.depth[n] = 0; - - } else { - tree[n * 2 + 1]/*.Len*/ = 0; - } - } - - /* The pkzip format requires that at least one distance code exists, - * and that at least one bit should be sent even if there is only one - * possible code. So to avoid special checks later on we force at least - * two codes of non zero frequency. - */ - while (s.heap_len < 2) { - node = s.heap[++s.heap_len] = (max_code < 2 ? ++max_code : 0); - tree[node * 2]/*.Freq*/ = 1; - s.depth[node] = 0; - s.opt_len--; - - if (has_stree) { - s.static_len -= stree[node * 2 + 1]/*.Len*/; - } - /* node is 0 or 1 so it does not have extra bits */ - } - desc.max_code = max_code; - - /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, - * establish sub-heaps of increasing lengths: - */ - for (n = (s.heap_len >> 1/*int /2*/); n >= 1; n--) { pqdownheap(s, tree, n); } - - /* Construct the Huffman tree by repeatedly combining the least two - * frequent nodes. - */ - node = elems; /* next internal node of the tree */ - do { - //pqremove(s, tree, n); /* n = node of least frequency */ - /*** pqremove ***/ - n = s.heap[1/*SMALLEST*/]; - s.heap[1/*SMALLEST*/] = s.heap[s.heap_len--]; - pqdownheap(s, tree, 1/*SMALLEST*/); - /***/ - - m = s.heap[1/*SMALLEST*/]; /* m = node of next least frequency */ - - s.heap[--s.heap_max] = n; /* keep the nodes sorted by frequency */ - s.heap[--s.heap_max] = m; - - /* Create a new node father of n and m */ - tree[node * 2]/*.Freq*/ = tree[n * 2]/*.Freq*/ + tree[m * 2]/*.Freq*/; - s.depth[node] = (s.depth[n] >= s.depth[m] ? s.depth[n] : s.depth[m]) + 1; - tree[n * 2 + 1]/*.Dad*/ = tree[m * 2 + 1]/*.Dad*/ = node; - - /* and insert the new node in the heap */ - s.heap[1/*SMALLEST*/] = node++; - pqdownheap(s, tree, 1/*SMALLEST*/); - - } while (s.heap_len >= 2); - - s.heap[--s.heap_max] = s.heap[1/*SMALLEST*/]; - - /* At this point, the fields freq and dad are set. We can now - * generate the bit lengths. - */ - gen_bitlen(s, desc); - - /* The field len is now set, we can generate the bit codes */ - gen_codes(tree, max_code, s.bl_count); -} - - -/* =========================================================================== - * Scan a literal or distance tree to determine the frequencies of the codes - * in the bit length tree. - */ -function scan_tree(s, tree, max_code) -// deflate_state *s; -// ct_data *tree; /* the tree to be scanned */ -// int max_code; /* and its largest code of non zero frequency */ -{ - var n; /* iterates over all tree elements */ - var prevlen = -1; /* last emitted length */ - var curlen; /* length of current code */ - - var nextlen = tree[0 * 2 + 1]/*.Len*/; /* length of next code */ - - var count = 0; /* repeat count of the current code */ - var max_count = 7; /* max repeat count */ - var min_count = 4; /* min repeat count */ - - if (nextlen === 0) { - max_count = 138; - min_count = 3; - } - tree[(max_code + 1) * 2 + 1]/*.Len*/ = 0xffff; /* guard */ - - for (n = 0; n <= max_code; n++) { - curlen = nextlen; - nextlen = tree[(n + 1) * 2 + 1]/*.Len*/; - - if (++count < max_count && curlen === nextlen) { - continue; - - } else if (count < min_count) { - s.bl_tree[curlen * 2]/*.Freq*/ += count; - - } else if (curlen !== 0) { - - if (curlen !== prevlen) { s.bl_tree[curlen * 2]/*.Freq*/++; } - s.bl_tree[REP_3_6 * 2]/*.Freq*/++; - - } else if (count <= 10) { - s.bl_tree[REPZ_3_10 * 2]/*.Freq*/++; - - } else { - s.bl_tree[REPZ_11_138 * 2]/*.Freq*/++; - } - - count = 0; - prevlen = curlen; - - if (nextlen === 0) { - max_count = 138; - min_count = 3; - - } else if (curlen === nextlen) { - max_count = 6; - min_count = 3; - - } else { - max_count = 7; - min_count = 4; - } - } -} - - -/* =========================================================================== - * Send a literal or distance tree in compressed form, using the codes in - * bl_tree. - */ -function send_tree(s, tree, max_code) -// deflate_state *s; -// ct_data *tree; /* the tree to be scanned */ -// int max_code; /* and its largest code of non zero frequency */ -{ - var n; /* iterates over all tree elements */ - var prevlen = -1; /* last emitted length */ - var curlen; /* length of current code */ - - var nextlen = tree[0 * 2 + 1]/*.Len*/; /* length of next code */ - - var count = 0; /* repeat count of the current code */ - var max_count = 7; /* max repeat count */ - var min_count = 4; /* min repeat count */ - - /* tree[max_code+1].Len = -1; */ /* guard already set */ - if (nextlen === 0) { - max_count = 138; - min_count = 3; - } - - for (n = 0; n <= max_code; n++) { - curlen = nextlen; - nextlen = tree[(n + 1) * 2 + 1]/*.Len*/; - - if (++count < max_count && curlen === nextlen) { - continue; - - } else if (count < min_count) { - do { send_code(s, curlen, s.bl_tree); } while (--count !== 0); - - } else if (curlen !== 0) { - if (curlen !== prevlen) { - send_code(s, curlen, s.bl_tree); - count--; - } - //Assert(count >= 3 && count <= 6, " 3_6?"); - send_code(s, REP_3_6, s.bl_tree); - send_bits(s, count - 3, 2); - - } else if (count <= 10) { - send_code(s, REPZ_3_10, s.bl_tree); - send_bits(s, count - 3, 3); - - } else { - send_code(s, REPZ_11_138, s.bl_tree); - send_bits(s, count - 11, 7); - } - - count = 0; - prevlen = curlen; - if (nextlen === 0) { - max_count = 138; - min_count = 3; - - } else if (curlen === nextlen) { - max_count = 6; - min_count = 3; - - } else { - max_count = 7; - min_count = 4; - } - } -} - - -/* =========================================================================== - * Construct the Huffman tree for the bit lengths and return the index in - * bl_order of the last bit length code to send. - */ -function build_bl_tree(s) { - var max_blindex; /* index of last bit length code of non zero freq */ - - /* Determine the bit length frequencies for literal and distance trees */ - scan_tree(s, s.dyn_ltree, s.l_desc.max_code); - scan_tree(s, s.dyn_dtree, s.d_desc.max_code); - - /* Build the bit length tree: */ - build_tree(s, s.bl_desc); - /* opt_len now includes the length of the tree representations, except - * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. - */ - - /* Determine the number of bit length codes to send. The pkzip format - * requires that at least 4 bit length codes be sent. (appnote.txt says - * 3 but the actual value used is 4.) - */ - for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) { - if (s.bl_tree[bl_order[max_blindex] * 2 + 1]/*.Len*/ !== 0) { - break; - } - } - /* Update opt_len to include the bit length tree and counts */ - s.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4; - //Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", - // s->opt_len, s->static_len)); - - return max_blindex; -} - - -/* =========================================================================== - * Send the header for a block using dynamic Huffman trees: the counts, the - * lengths of the bit length codes, the literal tree and the distance tree. - * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. - */ -function send_all_trees(s, lcodes, dcodes, blcodes) -// deflate_state *s; -// int lcodes, dcodes, blcodes; /* number of codes for each tree */ -{ - var rank; /* index in bl_order */ - - //Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); - //Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, - // "too many codes"); - //Tracev((stderr, "\nbl counts: ")); - send_bits(s, lcodes - 257, 5); /* not +255 as stated in appnote.txt */ - send_bits(s, dcodes - 1, 5); - send_bits(s, blcodes - 4, 4); /* not -3 as stated in appnote.txt */ - for (rank = 0; rank < blcodes; rank++) { - //Tracev((stderr, "\nbl code %2d ", bl_order[rank])); - send_bits(s, s.bl_tree[bl_order[rank] * 2 + 1]/*.Len*/, 3); - } - //Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); - - send_tree(s, s.dyn_ltree, lcodes - 1); /* literal tree */ - //Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); - - send_tree(s, s.dyn_dtree, dcodes - 1); /* distance tree */ - //Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); -} - - -/* =========================================================================== - * Check if the data type is TEXT or BINARY, using the following algorithm: - * - TEXT if the two conditions below are satisfied: - * a) There are no non-portable control characters belonging to the - * "black list" (0..6, 14..25, 28..31). - * b) There is at least one printable character belonging to the - * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). - * - BINARY otherwise. - * - The following partially-portable control characters form a - * "gray list" that is ignored in this detection algorithm: - * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). - * IN assertion: the fields Freq of dyn_ltree are set. - */ -function detect_data_type(s) { - /* black_mask is the bit mask of black-listed bytes - * set bits 0..6, 14..25, and 28..31 - * 0xf3ffc07f = binary 11110011111111111100000001111111 - */ - var black_mask = 0xf3ffc07f; - var n; - - /* Check for non-textual ("black-listed") bytes. */ - for (n = 0; n <= 31; n++, black_mask >>>= 1) { - if ((black_mask & 1) && (s.dyn_ltree[n * 2]/*.Freq*/ !== 0)) { - return Z_BINARY; - } - } - - /* Check for textual ("white-listed") bytes. */ - if (s.dyn_ltree[9 * 2]/*.Freq*/ !== 0 || s.dyn_ltree[10 * 2]/*.Freq*/ !== 0 || - s.dyn_ltree[13 * 2]/*.Freq*/ !== 0) { - return Z_TEXT; - } - for (n = 32; n < LITERALS; n++) { - if (s.dyn_ltree[n * 2]/*.Freq*/ !== 0) { - return Z_TEXT; - } - } - - /* There are no "black-listed" or "white-listed" bytes: - * this stream either is empty or has tolerated ("gray-listed") bytes only. - */ - return Z_BINARY; -} - - -var static_init_done = false; - -/* =========================================================================== - * Initialize the tree data structures for a new zlib stream. - */ -function _tr_init(s) -{ - - if (!static_init_done) { - tr_static_init(); - static_init_done = true; - } - - s.l_desc = new TreeDesc(s.dyn_ltree, static_l_desc); - s.d_desc = new TreeDesc(s.dyn_dtree, static_d_desc); - s.bl_desc = new TreeDesc(s.bl_tree, static_bl_desc); - - s.bi_buf = 0; - s.bi_valid = 0; - - /* Initialize the first block of the first file: */ - init_block(s); -} - - -/* =========================================================================== - * Send a stored block - */ -function _tr_stored_block(s, buf, stored_len, last) -//DeflateState *s; -//charf *buf; /* input block */ -//ulg stored_len; /* length of input block */ -//int last; /* one if this is the last block for a file */ -{ - send_bits(s, (STORED_BLOCK << 1) + (last ? 1 : 0), 3); /* send block type */ - copy_block(s, buf, stored_len, true); /* with header */ -} - - -/* =========================================================================== - * Send one empty static block to give enough lookahead for inflate. - * This takes 10 bits, of which 7 may remain in the bit buffer. - */ -function _tr_align(s) { - send_bits(s, STATIC_TREES << 1, 3); - send_code(s, END_BLOCK, static_ltree); - bi_flush(s); -} - - -/* =========================================================================== - * Determine the best encoding for the current block: dynamic trees, static - * trees or store, and output the encoded block to the zip file. - */ -function _tr_flush_block(s, buf, stored_len, last) -//DeflateState *s; -//charf *buf; /* input block, or NULL if too old */ -//ulg stored_len; /* length of input block */ -//int last; /* one if this is the last block for a file */ -{ - var opt_lenb, static_lenb; /* opt_len and static_len in bytes */ - var max_blindex = 0; /* index of last bit length code of non zero freq */ - - /* Build the Huffman trees unless a stored block is forced */ - if (s.level > 0) { - - /* Check if the file is binary or text */ - if (s.strm.data_type === Z_UNKNOWN) { - s.strm.data_type = detect_data_type(s); - } - - /* Construct the literal and distance trees */ - build_tree(s, s.l_desc); - // Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, - // s->static_len)); - - build_tree(s, s.d_desc); - // Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, - // s->static_len)); - /* At this point, opt_len and static_len are the total bit lengths of - * the compressed block data, excluding the tree representations. - */ - - /* Build the bit length tree for the above two trees, and get the index - * in bl_order of the last bit length code to send. - */ - max_blindex = build_bl_tree(s); - - /* Determine the best encoding. Compute the block lengths in bytes. */ - opt_lenb = (s.opt_len + 3 + 7) >>> 3; - static_lenb = (s.static_len + 3 + 7) >>> 3; - - // Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", - // opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, - // s->last_lit)); - - if (static_lenb <= opt_lenb) { opt_lenb = static_lenb; } - - } else { - // Assert(buf != (char*)0, "lost buf"); - opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ - } - - if ((stored_len + 4 <= opt_lenb) && (buf !== -1)) { - /* 4: two words for the lengths */ - - /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. - * Otherwise we can't have processed more than WSIZE input bytes since - * the last block flush, because compression would have been - * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to - * transform a block into a stored block. - */ - _tr_stored_block(s, buf, stored_len, last); - - } else if (s.strategy === Z_FIXED || static_lenb === opt_lenb) { - - send_bits(s, (STATIC_TREES << 1) + (last ? 1 : 0), 3); - compress_block(s, static_ltree, static_dtree); - - } else { - send_bits(s, (DYN_TREES << 1) + (last ? 1 : 0), 3); - send_all_trees(s, s.l_desc.max_code + 1, s.d_desc.max_code + 1, max_blindex + 1); - compress_block(s, s.dyn_ltree, s.dyn_dtree); - } - // Assert (s->compressed_len == s->bits_sent, "bad compressed size"); - /* The above check is made mod 2^32, for files larger than 512 MB - * and uLong implemented on 32 bits. - */ - init_block(s); - - if (last) { - bi_windup(s); - } - // Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, - // s->compressed_len-7*last)); -} - -/* =========================================================================== - * Save the match info and tally the frequency counts. Return true if - * the current block must be flushed. - */ -function _tr_tally(s, dist, lc) -// deflate_state *s; -// unsigned dist; /* distance of matched string */ -// unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ -{ - //var out_length, in_length, dcode; - - s.pending_buf[s.d_buf + s.last_lit * 2] = (dist >>> 8) & 0xff; - s.pending_buf[s.d_buf + s.last_lit * 2 + 1] = dist & 0xff; - - s.pending_buf[s.l_buf + s.last_lit] = lc & 0xff; - s.last_lit++; - - if (dist === 0) { - /* lc is the unmatched char */ - s.dyn_ltree[lc * 2]/*.Freq*/++; - } else { - s.matches++; - /* Here, lc is the match length - MIN_MATCH */ - dist--; /* dist = match distance - 1 */ - //Assert((ush)dist < (ush)MAX_DIST(s) && - // (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && - // (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); - - s.dyn_ltree[(_length_code[lc] + LITERALS + 1) * 2]/*.Freq*/++; - s.dyn_dtree[d_code(dist) * 2]/*.Freq*/++; - } - -// (!) This block is disabled in zlib defaults, -// don't enable it for binary compatibility - -//#ifdef TRUNCATE_BLOCK -// /* Try to guess if it is profitable to stop the current block here */ -// if ((s.last_lit & 0x1fff) === 0 && s.level > 2) { -// /* Compute an upper bound for the compressed length */ -// out_length = s.last_lit*8; -// in_length = s.strstart - s.block_start; -// -// for (dcode = 0; dcode < D_CODES; dcode++) { -// out_length += s.dyn_dtree[dcode*2]/*.Freq*/ * (5 + extra_dbits[dcode]); -// } -// out_length >>>= 3; -// //Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", -// // s->last_lit, in_length, out_length, -// // 100L - out_length*100L/in_length)); -// if (s.matches < (s.last_lit>>1)/*int /2*/ && out_length < (in_length>>1)/*int /2*/) { -// return true; -// } -// } -//#endif - - return (s.last_lit === s.lit_bufsize - 1); - /* We avoid equality with lit_bufsize because of wraparound at 64K - * on 16 bit machines and because stored blocks are restricted to - * 64K-1 bytes. - */ -} - -exports._tr_init = _tr_init; -exports._tr_stored_block = _tr_stored_block; -exports._tr_flush_block = _tr_flush_block; -exports._tr_tally = _tr_tally; -exports._tr_align = _tr_align; |