733 lines
25 KiB
JavaScript
733 lines
25 KiB
JavaScript
/*
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* Port of script by Masanao Izumo.
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*
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* Wrapped all the variables in a function, created a
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* constructor for interacting with the lib. Everything
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* else was written by M. Izumo.
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*
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* Original code can be found here: http://www.onicos.com/staff/iz/amuse/javascript/expert/inflate.txt
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*
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*/
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var zip_WSIZE = 32768; // Sliding Window size
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var zip_STORED_BLOCK = 0;
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var zip_STATIC_TREES = 1;
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var zip_DYN_TREES = 2;
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/* for inflate */
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var zip_lbits = 9; // bits in base literal/length lookup table
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var zip_dbits = 6; // bits in base distance lookup table
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var zip_INBUFSIZ = 32768; // Input buffer size
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var zip_INBUF_EXTRA = 64; // Extra buffer
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/* variables (inflate) */
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var zip_slide;
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var zip_wp; // current position in slide
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var zip_fixed_tl = null; // inflate static
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var zip_fixed_td; // inflate static
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var zip_fixed_bl, fixed_bd; // inflate static
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var zip_bit_buf; // bit buffer
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var zip_bit_len; // bits in bit buffer
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var zip_method;
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var zip_eof;
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var zip_copy_leng;
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var zip_copy_dist;
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var zip_tl, zip_td; // literal/length and distance decoder tables
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var zip_bl, zip_bd; // number of bits decoded by tl and td
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var zip_inflate_data;
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var zip_inflate_pos;
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/* constant tables (inflate) */
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var zip_MASK_BITS = new Array(
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0x0000,
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0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
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0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff);
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// Tables for deflate from PKZIP's appnote.txt.
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var zip_cplens = new Array( // Copy lengths for literal codes 257..285
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3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
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35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0);
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/* note: see note #13 above about the 258 in this list. */
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var zip_cplext = new Array( // Extra bits for literal codes 257..285
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0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
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3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99); // 99==invalid
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var zip_cpdist = new Array( // Copy offsets for distance codes 0..29
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1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
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257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
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8193, 12289, 16385, 24577);
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var zip_cpdext = new Array( // Extra bits for distance codes
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0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
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7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
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12, 12, 13, 13);
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var zip_border = new Array( // Order of the bit length code lengths
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16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15);
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/* objects (inflate) */
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function zip_HuftList() {
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this.next = null;
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this.list = null;
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}
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function zip_HuftNode() {
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this.e = 0; // number of extra bits or operation
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this.b = 0; // number of bits in this code or subcode
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// union
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this.n = 0; // literal, length base, or distance base
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this.t = null; // (zip_HuftNode) pointer to next level of table
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}
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function zip_HuftBuild(b, // code lengths in bits (all assumed <= BMAX)
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n, // number of codes (assumed <= N_MAX)
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s, // number of simple-valued codes (0..s-1)
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d, // list of base values for non-simple codes
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e, // list of extra bits for non-simple codes
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mm // maximum lookup bits
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) {
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this.BMAX = 16; // maximum bit length of any code
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this.N_MAX = 288; // maximum number of codes in any set
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this.status = 0; // 0: success, 1: incomplete table, 2: bad input
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this.root = null; // (zip_HuftList) starting table
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this.m = 0; // maximum lookup bits, returns actual
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/* Given a list of code lengths and a maximum table size, make a set of
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tables to decode that set of codes. Return zero on success, one if
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the given code set is incomplete (the tables are still built in this
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case), two if the input is invalid (all zero length codes or an
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oversubscribed set of lengths), and three if not enough memory.
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The code with value 256 is special, and the tables are constructed
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so that no bits beyond that code are fetched when that code is
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decoded. */
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{
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var a; // counter for codes of length k
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var c = new Array(this.BMAX + 1); // bit length count table
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var el; // length of EOB code (value 256)
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var f; // i repeats in table every f entries
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var g; // maximum code length
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var h; // table level
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var i; // counter, current code
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var j; // counter
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var k; // number of bits in current code
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var lx = new Array(this.BMAX + 1); // stack of bits per table
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var p; // pointer into c[], b[], or v[]
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var pidx; // index of p
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var q; // (zip_HuftNode) points to current table
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var r = new zip_HuftNode(); // table entry for structure assignment
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var u = new Array(this.BMAX); // zip_HuftNode[BMAX][] table stack
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var v = new Array(this.N_MAX); // values in order of bit length
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var w;
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var x = new Array(this.BMAX + 1);// bit offsets, then code stack
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var xp; // pointer into x or c
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var y; // number of dummy codes added
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var z; // number of entries in current table
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var o;
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var tail; // (zip_HuftList)
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tail = this.root = null;
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for (i = 0; i < c.length; i++)
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c[i] = 0;
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for (i = 0; i < lx.length; i++)
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lx[i] = 0;
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for (i = 0; i < u.length; i++)
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u[i] = null;
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for (i = 0; i < v.length; i++)
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v[i] = 0;
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for (i = 0; i < x.length; i++)
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x[i] = 0;
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// Generate counts for each bit length
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el = n > 256 ? b[256] : this.BMAX; // set length of EOB code, if any
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p = b; pidx = 0;
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i = n;
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do {
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c[p[pidx]]++; // assume all entries <= BMAX
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pidx++;
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} while (--i > 0);
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if (c[0] == n) { // null input--all zero length codes
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this.root = null;
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this.m = 0;
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this.status = 0;
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return;
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}
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// Find minimum and maximum length, bound *m by those
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for (j = 1; j <= this.BMAX; j++)
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if (c[j] != 0)
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break;
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k = j; // minimum code length
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if (mm < j)
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mm = j;
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for (i = this.BMAX; i != 0; i--)
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if (c[i] != 0)
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break;
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g = i; // maximum code length
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if (mm > i)
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mm = i;
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// Adjust last length count to fill out codes, if needed
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for (y = 1 << j; j < i; j++, y <<= 1)
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if ((y -= c[j]) < 0) {
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this.status = 2; // bad input: more codes than bits
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this.m = mm;
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return;
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}
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if ((y -= c[i]) < 0) {
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this.status = 2;
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this.m = mm;
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return;
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}
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c[i] += y;
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// Generate starting offsets into the value table for each length
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x[1] = j = 0;
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p = c;
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pidx = 1;
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xp = 2;
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while (--i > 0) // note that i == g from above
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x[xp++] = (j += p[pidx++]);
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// Make a table of values in order of bit lengths
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p = b; pidx = 0;
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i = 0;
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do {
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if ((j = p[pidx++]) != 0)
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v[x[j]++] = i;
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} while (++i < n);
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n = x[g]; // set n to length of v
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// Generate the Huffman codes and for each, make the table entries
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x[0] = i = 0; // first Huffman code is zero
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p = v; pidx = 0; // grab values in bit order
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h = -1; // no tables yet--level -1
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w = lx[0] = 0; // no bits decoded yet
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q = null; // ditto
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z = 0; // ditto
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// go through the bit lengths (k already is bits in shortest code)
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for (; k <= g; k++) {
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a = c[k];
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while (a-- > 0) {
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// here i is the Huffman code of length k bits for value p[pidx]
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// make tables up to required level
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while (k > w + lx[1 + h]) {
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w += lx[1 + h]; // add bits already decoded
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h++;
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// compute minimum size table less than or equal to *m bits
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z = (z = g - w) > mm ? mm : z; // upper limit
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if ((f = 1 << (j = k - w)) > a + 1) { // try a k-w bit table
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// too few codes for k-w bit table
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f -= a + 1; // deduct codes from patterns left
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xp = k;
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while (++j < z) { // try smaller tables up to z bits
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if ((f <<= 1) <= c[++xp])
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break; // enough codes to use up j bits
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f -= c[xp]; // else deduct codes from patterns
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}
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}
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if (w + j > el && w < el)
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j = el - w; // make EOB code end at table
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z = 1 << j; // table entries for j-bit table
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lx[1 + h] = j; // set table size in stack
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// allocate and link in new table
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q = new Array(z);
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for (o = 0; o < z; o++) {
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q[o] = new zip_HuftNode();
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}
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if (tail == null)
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tail = this.root = new zip_HuftList();
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else
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tail = tail.next = new zip_HuftList();
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tail.next = null;
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tail.list = q;
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u[h] = q; // table starts after link
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/* connect to last table, if there is one */
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if (h > 0) {
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x[h] = i; // save pattern for backing up
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r.b = lx[h]; // bits to dump before this table
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r.e = 16 + j; // bits in this table
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r.t = q; // pointer to this table
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j = (i & ((1 << w) - 1)) >> (w - lx[h]);
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u[h - 1][j].e = r.e;
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u[h - 1][j].b = r.b;
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u[h - 1][j].n = r.n;
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u[h - 1][j].t = r.t;
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}
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}
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// set up table entry in r
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r.b = k - w;
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if (pidx >= n)
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r.e = 99; // out of values--invalid code
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else if (p[pidx] < s) {
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r.e = (p[pidx] < 256 ? 16 : 15); // 256 is end-of-block code
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r.n = p[pidx++]; // simple code is just the value
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} else {
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r.e = e[p[pidx] - s]; // non-simple--look up in lists
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r.n = d[p[pidx++] - s];
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}
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// fill code-like entries with r //
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f = 1 << (k - w);
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for (j = i >> w; j < z; j += f) {
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q[j].e = r.e;
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q[j].b = r.b;
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q[j].n = r.n;
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q[j].t = r.t;
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}
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// backwards increment the k-bit code i
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for (j = 1 << (k - 1) ; (i & j) != 0; j >>= 1)
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i ^= j;
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i ^= j;
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// backup over finished tables
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while ((i & ((1 << w) - 1)) != x[h]) {
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w -= lx[h]; // don't need to update q
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h--;
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}
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}
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}
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/* return actual size of base table */
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this.m = lx[1];
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/* Return true (1) if we were given an incomplete table */
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this.status = ((y != 0 && g != 1) ? 1 : 0);
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} /* end of constructor */
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}
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/* routines (inflate) */
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function zip_GET_BYTE() {
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if (zip_inflate_data.length == zip_inflate_pos)
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return -1;
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return zip_inflate_data.charCodeAt(zip_inflate_pos++) & 0xff;
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}
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function zip_NEEDBITS(n) {
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while (zip_bit_len < n) {
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zip_bit_buf |= zip_GET_BYTE() << zip_bit_len;
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zip_bit_len += 8;
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}
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}
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function zip_GETBITS(n) {
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return zip_bit_buf & zip_MASK_BITS[n];
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}
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function zip_DUMPBITS(n) {
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zip_bit_buf >>= n;
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zip_bit_len -= n;
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}
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function zip_inflate_codes(buff, off, size) {
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/* inflate (decompress) the codes in a deflated (compressed) block.
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Return an error code or zero if it all goes ok. */
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var e; // table entry flag/number of extra bits
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var t; // (zip_HuftNode) pointer to table entry
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var n;
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if (size == 0)
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return 0;
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// inflate the coded data
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n = 0;
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for (; ;) { // do until end of block
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zip_NEEDBITS(zip_bl);
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t = zip_tl.list[zip_GETBITS(zip_bl)];
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e = t.e;
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while (e > 16) {
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if (e == 99)
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return -1;
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zip_DUMPBITS(t.b);
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e -= 16;
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zip_NEEDBITS(e);
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t = t.t[zip_GETBITS(e)];
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e = t.e;
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}
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zip_DUMPBITS(t.b);
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if (e == 16) { // then it's a literal
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zip_wp &= zip_WSIZE - 1;
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buff[off + n++] = zip_slide[zip_wp++] = t.n;
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if (n == size)
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return size;
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continue;
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}
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// exit if end of block
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if (e == 15)
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break;
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// it's an EOB or a length
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// get length of block to copy
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zip_NEEDBITS(e);
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zip_copy_leng = t.n + zip_GETBITS(e);
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zip_DUMPBITS(e);
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// decode distance of block to copy
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zip_NEEDBITS(zip_bd);
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t = zip_td.list[zip_GETBITS(zip_bd)];
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e = t.e;
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while (e > 16) {
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if (e == 99)
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return -1;
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zip_DUMPBITS(t.b);
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e -= 16;
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zip_NEEDBITS(e);
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t = t.t[zip_GETBITS(e)];
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e = t.e;
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}
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zip_DUMPBITS(t.b);
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zip_NEEDBITS(e);
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zip_copy_dist = zip_wp - t.n - zip_GETBITS(e);
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zip_DUMPBITS(e);
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// do the copy
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while (zip_copy_leng > 0 && n < size) {
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zip_copy_leng--;
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zip_copy_dist &= zip_WSIZE - 1;
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zip_wp &= zip_WSIZE - 1;
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buff[off + n++] = zip_slide[zip_wp++]
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= zip_slide[zip_copy_dist++];
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}
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if (n == size)
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return size;
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}
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zip_method = -1; // done
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return n;
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}
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function zip_inflate_stored(buff, off, size) {
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/* "decompress" an inflated type 0 (stored) block. */
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var n;
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// go to byte boundary
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n = zip_bit_len & 7;
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zip_DUMPBITS(n);
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// get the length and its complement
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zip_NEEDBITS(16);
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n = zip_GETBITS(16);
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zip_DUMPBITS(16);
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zip_NEEDBITS(16);
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if (n != ((~zip_bit_buf) & 0xffff))
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return -1; // error in compressed data
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zip_DUMPBITS(16);
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// read and output the compressed data
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zip_copy_leng = n;
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n = 0;
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while (zip_copy_leng > 0 && n < size) {
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zip_copy_leng--;
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zip_wp &= zip_WSIZE - 1;
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zip_NEEDBITS(8);
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buff[off + n++] = zip_slide[zip_wp++] =
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zip_GETBITS(8);
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zip_DUMPBITS(8);
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}
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if (zip_copy_leng == 0)
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zip_method = -1; // done
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return n;
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}
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function zip_inflate_fixed(buff, off, size) {
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/* decompress an inflated type 1 (fixed Huffman codes) block. We should
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either replace this with a custom decoder, or at least precompute the
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Huffman tables. */
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// if first time, set up tables for fixed blocks
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if (zip_fixed_tl == null) {
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var i; // temporary variable
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var l = new Array(288); // length list for huft_build
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var h; // zip_HuftBuild
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// literal table
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for (i = 0; i < 144; i++)
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l[i] = 8;
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for (; i < 256; i++)
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l[i] = 9;
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for (; i < 280; i++)
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l[i] = 7;
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for (; i < 288; i++) // make a complete, but wrong code set
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l[i] = 8;
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zip_fixed_bl = 7;
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h = new zip_HuftBuild(l, 288, 257, zip_cplens, zip_cplext,
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zip_fixed_bl);
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if (h.status != 0) {
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alert("HufBuild error: " + h.status);
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return -1;
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}
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zip_fixed_tl = h.root;
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zip_fixed_bl = h.m;
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// distance table
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for (i = 0; i < 30; i++) // make an incomplete code set
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l[i] = 5;
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zip_fixed_bd = 5;
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h = new zip_HuftBuild(l, 30, 0, zip_cpdist, zip_cpdext, zip_fixed_bd);
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if (h.status > 1) {
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zip_fixed_tl = null;
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alert("HufBuild error: " + h.status);
|
|
return -1;
|
|
}
|
|
zip_fixed_td = h.root;
|
|
zip_fixed_bd = h.m;
|
|
}
|
|
|
|
zip_tl = zip_fixed_tl;
|
|
zip_td = zip_fixed_td;
|
|
zip_bl = zip_fixed_bl;
|
|
zip_bd = zip_fixed_bd;
|
|
return zip_inflate_codes(buff, off, size);
|
|
}
|
|
|
|
function zip_inflate_dynamic(buff, off, size) {
|
|
// decompress an inflated type 2 (dynamic Huffman codes) block.
|
|
var i; // temporary variables
|
|
var j;
|
|
var l; // last length
|
|
var n; // number of lengths to get
|
|
var t; // (zip_HuftNode) literal/length code table
|
|
var nb; // number of bit length codes
|
|
var nl; // number of literal/length codes
|
|
var nd; // number of distance codes
|
|
var ll = new Array(286 + 30); // literal/length and distance code lengths
|
|
var h; // (zip_HuftBuild)
|
|
|
|
for (i = 0; i < ll.length; i++)
|
|
ll[i] = 0;
|
|
|
|
// read in table lengths
|
|
zip_NEEDBITS(5);
|
|
nl = 257 + zip_GETBITS(5); // number of literal/length codes
|
|
zip_DUMPBITS(5);
|
|
zip_NEEDBITS(5);
|
|
nd = 1 + zip_GETBITS(5); // number of distance codes
|
|
zip_DUMPBITS(5);
|
|
zip_NEEDBITS(4);
|
|
nb = 4 + zip_GETBITS(4); // number of bit length codes
|
|
zip_DUMPBITS(4);
|
|
if (nl > 286 || nd > 30)
|
|
return -1; // bad lengths
|
|
|
|
// read in bit-length-code lengths
|
|
for (j = 0; j < nb; j++) {
|
|
zip_NEEDBITS(3);
|
|
ll[zip_border[j]] = zip_GETBITS(3);
|
|
zip_DUMPBITS(3);
|
|
}
|
|
for (; j < 19; j++)
|
|
ll[zip_border[j]] = 0;
|
|
|
|
// build decoding table for trees--single level, 7 bit lookup
|
|
zip_bl = 7;
|
|
h = new zip_HuftBuild(ll, 19, 19, null, null, zip_bl);
|
|
if (h.status != 0)
|
|
return -1; // incomplete code set
|
|
|
|
zip_tl = h.root;
|
|
zip_bl = h.m;
|
|
|
|
// read in literal and distance code lengths
|
|
n = nl + nd;
|
|
i = l = 0;
|
|
while (i < n) {
|
|
zip_NEEDBITS(zip_bl);
|
|
t = zip_tl.list[zip_GETBITS(zip_bl)];
|
|
j = t.b;
|
|
zip_DUMPBITS(j);
|
|
j = t.n;
|
|
if (j < 16) // length of code in bits (0..15)
|
|
ll[i++] = l = j; // save last length in l
|
|
else if (j == 16) { // repeat last length 3 to 6 times
|
|
zip_NEEDBITS(2);
|
|
j = 3 + zip_GETBITS(2);
|
|
zip_DUMPBITS(2);
|
|
if (i + j > n)
|
|
return -1;
|
|
while (j-- > 0)
|
|
ll[i++] = l;
|
|
} else if (j == 17) { // 3 to 10 zero length codes
|
|
zip_NEEDBITS(3);
|
|
j = 3 + zip_GETBITS(3);
|
|
zip_DUMPBITS(3);
|
|
if (i + j > n)
|
|
return -1;
|
|
while (j-- > 0)
|
|
ll[i++] = 0;
|
|
l = 0;
|
|
} else { // j == 18: 11 to 138 zero length codes
|
|
zip_NEEDBITS(7);
|
|
j = 11 + zip_GETBITS(7);
|
|
zip_DUMPBITS(7);
|
|
if (i + j > n)
|
|
return -1;
|
|
while (j-- > 0)
|
|
ll[i++] = 0;
|
|
l = 0;
|
|
}
|
|
}
|
|
|
|
// build the decoding tables for literal/length and distance codes
|
|
zip_bl = zip_lbits;
|
|
h = new zip_HuftBuild(ll, nl, 257, zip_cplens, zip_cplext, zip_bl);
|
|
if (zip_bl == 0) // no literals or lengths
|
|
h.status = 1;
|
|
if (h.status != 0) {
|
|
if (h.status == 1)
|
|
;// **incomplete literal tree**
|
|
return -1; // incomplete code set
|
|
}
|
|
zip_tl = h.root;
|
|
zip_bl = h.m;
|
|
|
|
for (i = 0; i < nd; i++)
|
|
ll[i] = ll[i + nl];
|
|
zip_bd = zip_dbits;
|
|
h = new zip_HuftBuild(ll, nd, 0, zip_cpdist, zip_cpdext, zip_bd);
|
|
zip_td = h.root;
|
|
zip_bd = h.m;
|
|
|
|
if (zip_bd == 0 && nl > 257) { // lengths but no distances
|
|
// **incomplete distance tree**
|
|
return -1;
|
|
}
|
|
|
|
if (h.status == 1) {
|
|
;// **incomplete distance tree**
|
|
}
|
|
if (h.status != 0)
|
|
return -1;
|
|
|
|
// decompress until an end-of-block code
|
|
return zip_inflate_codes(buff, off, size);
|
|
}
|
|
|
|
function zip_inflate_internal(buff, off, size) {
|
|
// decompress an inflated entry
|
|
var n, i;
|
|
|
|
n = 0;
|
|
while (n < size) {
|
|
if (zip_eof && zip_method == -1)
|
|
return n;
|
|
|
|
if (zip_copy_leng > 0) {
|
|
if (zip_method != zip_STORED_BLOCK) {
|
|
// STATIC_TREES or DYN_TREES
|
|
while (zip_copy_leng > 0 && n < size) {
|
|
zip_copy_leng--;
|
|
zip_copy_dist &= zip_WSIZE - 1;
|
|
zip_wp &= zip_WSIZE - 1;
|
|
buff[off + n++] = zip_slide[zip_wp++] =
|
|
zip_slide[zip_copy_dist++];
|
|
}
|
|
} else {
|
|
while (zip_copy_leng > 0 && n < size) {
|
|
zip_copy_leng--;
|
|
zip_wp &= zip_WSIZE - 1;
|
|
zip_NEEDBITS(8);
|
|
buff[off + n++] = zip_slide[zip_wp++] = zip_GETBITS(8);
|
|
zip_DUMPBITS(8);
|
|
}
|
|
if (zip_copy_leng == 0)
|
|
zip_method = -1; // done
|
|
}
|
|
if (n == size)
|
|
return n;
|
|
}
|
|
|
|
if (zip_method == -1) {
|
|
if (zip_eof)
|
|
break;
|
|
|
|
// read in last block bit
|
|
zip_NEEDBITS(1);
|
|
if (zip_GETBITS(1) != 0)
|
|
zip_eof = true;
|
|
zip_DUMPBITS(1);
|
|
|
|
// read in block type
|
|
zip_NEEDBITS(2);
|
|
zip_method = zip_GETBITS(2);
|
|
zip_DUMPBITS(2);
|
|
zip_tl = null;
|
|
zip_copy_leng = 0;
|
|
}
|
|
|
|
switch (zip_method) {
|
|
case 0: // zip_STORED_BLOCK
|
|
i = zip_inflate_stored(buff, off + n, size - n);
|
|
break;
|
|
|
|
case 1: // zip_STATIC_TREES
|
|
if (zip_tl != null)
|
|
i = zip_inflate_codes(buff, off + n, size - n);
|
|
else
|
|
i = zip_inflate_fixed(buff, off + n, size - n);
|
|
break;
|
|
|
|
case 2: // zip_DYN_TREES
|
|
if (zip_tl != null)
|
|
i = zip_inflate_codes(buff, off + n, size - n);
|
|
else
|
|
i = zip_inflate_dynamic(buff, off + n, size - n);
|
|
break;
|
|
|
|
default: // error
|
|
i = -1;
|
|
break;
|
|
}
|
|
|
|
if (i == -1) {
|
|
if (zip_eof)
|
|
return 0;
|
|
return -1;
|
|
}
|
|
n += i;
|
|
}
|
|
return n;
|
|
}
|
|
|
|
function zip_inflate_start() {
|
|
if (zip_slide == null) zip_slide = new Array(2 * zip_WSIZE);
|
|
zip_wp = 0;
|
|
zip_bit_buf = 0;
|
|
zip_bit_len = 0;
|
|
zip_method = -1;
|
|
zip_eof = false;
|
|
zip_copy_leng = zip_copy_dist = 0;
|
|
zip_tl = null;
|
|
}
|
|
|
|
inflate_start = function () { zip_inflate_start(); };
|
|
inflate = function (data) {
|
|
var out = "", buff = [], i, j;
|
|
zip_bit_buf = 0;
|
|
zip_bit_len = 0;
|
|
zip_method = -1;
|
|
zip_eof = false;
|
|
zip_inflate_data = data;
|
|
zip_inflate_pos = 0;
|
|
|
|
do { i = zip_inflate_internal(buff, buff.length, 1024); } while (i > 0);
|
|
zip_inflate_data = null; // G.C.
|
|
|
|
return buff;
|
|
};
|