'use strict'; 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) */ 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]; /* 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 insdead 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) */ var StaticTreeDesc = function (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; var TreeDesc = function(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 defailts, // 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;
# | Change | User | Description | Committed | |
---|---|---|---|---|---|
#1 | 19553 | swellard | Move and rename clients | ||
//guest/perforce_software/helix-web-services/main/source/clients/2016.1.0/javascript/node_modules/pako/lib/zlib/trees.js | |||||
#1 | 18810 | tjuricek |
First-pass at JavaScript client SDK. JavaScript requires Node with Gulp to "browserfy" the library. It's the easiest way I found to use the swagger-js project; bundle up a wrapping method. There is no JavaScript reference guide. The swagger-js doesn't really document what they do very well, actually. Overall I'm not particularly impressed by swagger-js, it was hard to even figure out what the right method syntax was. We may want to invest time in doing it better. This required setting CORS response headers, which are currently defaulted to a fairly insecure setting. |