/* Copyright (C) 1999,2012 Masanao Izumo * Version: 1.0.1 * LastModified: Jun 29 2012 */ /* Interface: * data = zip_inflate(src); */ /* constant parameters */ var zip_WSIZE = 32768; // Sliding Window size var zip_STORED_BLOCK = 0; var zip_STATIC_TREES = 1; var zip_DYN_TREES = 2; /* for inflate */ var zip_lbits = 9; // bits in base literal/length lookup table var zip_dbits = 6; // bits in base distance lookup table var zip_INBUFSIZ = 32768; // Input buffer size var zip_INBUF_EXTRA = 64; // Extra buffer /* variables (inflate) */ var zip_slide; var zip_wp; // current position in slide var zip_fixed_tl = null; // inflate static var zip_fixed_td; // inflate static var zip_fixed_bl, fixed_bd; // inflate static var zip_bit_buf; // bit buffer var zip_bit_len; // bits in bit buffer var zip_method; var zip_eof; var zip_copy_leng; var zip_copy_dist; var zip_tl, zip_td; // literal/length and distance decoder tables var zip_bl, zip_bd; // number of bits decoded by tl and td var zip_inflate_data; var zip_inflate_pos; /* constant tables (inflate) */ var zip_MASK_BITS = new Array( 0x0000, 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff); // Tables for deflate from PKZIP's appnote.txt. var zip_cplens = new Array( // Copy lengths for literal codes 257..285 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0); /* note: see note #13 above about the 258 in this list. */ var zip_cplext = new Array( // Extra bits for literal codes 257..285 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, 99, 99); // 99==invalid var zip_cpdist = new Array( // Copy offsets for distance codes 0..29 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577); var zip_cpdext = new Array( // Extra bits for distance codes 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 zip_border = new Array( // Order of the bit length code lengths 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15); /* objects (inflate) */ function zip_HuftList() { this.next = null; this.list = null; } function zip_HuftNode() { this.e = 0; // number of extra bits or operation this.b = 0; // number of bits in this code or subcode // union this.n = 0; // literal, length base, or distance base this.t = null; // (zip_HuftNode) pointer to next level of table } function zip_HuftBuild(b, // code lengths in bits (all assumed <= BMAX) n, // number of codes (assumed <= N_MAX) s, // number of simple-valued codes (0..s-1) d, // list of base values for non-simple codes e, // list of extra bits for non-simple codes mm // maximum lookup bits ) { this.BMAX = 16; // maximum bit length of any code this.N_MAX = 288; // maximum number of codes in any set this.status = 0; // 0: success, 1: incomplete table, 2: bad input this.root = null; // (zip_HuftList) starting table this.m = 0; // maximum lookup bits, returns actual /* Given a list of code lengths and a maximum table size, make a set of tables to decode that set of codes. Return zero on success, one if the given code set is incomplete (the tables are still built in this case), two if the input is invalid (all zero length codes or an oversubscribed set of lengths), and three if not enough memory. The code with value 256 is special, and the tables are constructed so that no bits beyond that code are fetched when that code is decoded. */ { var a; // counter for codes of length k var c = new Array(this.BMAX+1); // bit length count table var el; // length of EOB code (value 256) var f; // i repeats in table every f entries var g; // maximum code length var h; // table level var i; // counter, current code var j; // counter var k; // number of bits in current code var lx = new Array(this.BMAX+1); // stack of bits per table var p; // pointer into c[], b[], or v[] var pidx; // index of p var q; // (zip_HuftNode) points to current table var r = new zip_HuftNode(); // table entry for structure assignment var u = new Array(this.BMAX); // zip_HuftNode[BMAX][] table stack var v = new Array(this.N_MAX); // values in order of bit length var w; var x = new Array(this.BMAX+1);// bit offsets, then code stack var xp; // pointer into x or c var y; // number of dummy codes added var z; // number of entries in current table var o; var tail; // (zip_HuftList) tail = this.root = null; for(i = 0; i < c.length; i++) c[i] = 0; for(i = 0; i < lx.length; i++) lx[i] = 0; for(i = 0; i < u.length; i++) u[i] = null; for(i = 0; i < v.length; i++) v[i] = 0; for(i = 0; i < x.length; i++) x[i] = 0; // Generate counts for each bit length el = n > 256 ? b[256] : this.BMAX; // set length of EOB code, if any p = b; pidx = 0; i = n; do { c[p[pidx]]++; // assume all entries <= BMAX pidx++; } while(--i > 0); if(c[0] == n) { // null input--all zero length codes this.root = null; this.m = 0; this.status = 0; return; } // Find minimum and maximum length, bound *m by those for(j = 1; j <= this.BMAX; j++) if(c[j] != 0) break; k = j; // minimum code length if(mm < j) mm = j; for(i = this.BMAX; i != 0; i--) if(c[i] != 0) break; g = i; // maximum code length if(mm > i) mm = i; // Adjust last length count to fill out codes, if needed for(y = 1 << j; j < i; j++, y <<= 1) if((y -= c[j]) < 0) { this.status = 2; // bad input: more codes than bits this.m = mm; return; } if((y -= c[i]) < 0) { this.status = 2; this.m = mm; return; } c[i] += y; // Generate starting offsets into the value table for each length x[1] = j = 0; p = c; pidx = 1; xp = 2; while(--i > 0) // note that i == g from above x[xp++] = (j += p[pidx++]); // Make a table of values in order of bit lengths p = b; pidx = 0; i = 0; do { if((j = p[pidx++]) != 0) v[x[j]++] = i; } while(++i < n); n = x[g]; // set n to length of v // Generate the Huffman codes and for each, make the table entries x[0] = i = 0; // first Huffman code is zero p = v; pidx = 0; // grab values in bit order h = -1; // no tables yet--level -1 w = lx[0] = 0; // no bits decoded yet q = null; // ditto z = 0; // ditto // go through the bit lengths (k already is bits in shortest code) for(; k <= g; k++) { a = c[k]; while(a-- > 0) { // here i is the Huffman code of length k bits for value p[pidx] // make tables up to required level while(k > w + lx[1 + h]) { w += lx[1 + h]; // add bits already decoded h++; // compute minimum size table less than or equal to *m bits z = (z = g - w) > mm ? mm : z; // upper limit if((f = 1 << (j = k - w)) > a + 1) { // try a k-w bit table // too few codes for k-w bit table f -= a + 1; // deduct codes from patterns left xp = k; while(++j < z) { // try smaller tables up to z bits if((f <<= 1) <= c[++xp]) break; // enough codes to use up j bits f -= c[xp]; // else deduct codes from patterns } } if(w + j > el && w < el) j = el - w; // make EOB code end at table z = 1 << j; // table entries for j-bit table lx[1 + h] = j; // set table size in stack // allocate and link in new table q = new Array(z); for(o = 0; o < z; o++) { q[o] = new zip_HuftNode(); } if(tail == null) tail = this.root = new zip_HuftList(); else tail = tail.next = new zip_HuftList(); tail.next = null; tail.list = q; u[h] = q; // table starts after link /* connect to last table, if there is one */ if(h > 0) { x[h] = i; // save pattern for backing up r.b = lx[h]; // bits to dump before this table r.e = 16 + j; // bits in this table r.t = q; // pointer to this table j = (i & ((1 << w) - 1)) >> (w - lx[h]); u[h-1][j].e = r.e; u[h-1][j].b = r.b; u[h-1][j].n = r.n; u[h-1][j].t = r.t; } } // set up table entry in r r.b = k - w; if(pidx >= n) r.e = 99; // out of values--invalid code else if(p[pidx] < s) { r.e = (p[pidx] < 256 ? 16 : 15); // 256 is end-of-block code r.n = p[pidx++]; // simple code is just the value } else { r.e = e[p[pidx] - s]; // non-simple--look up in lists r.n = d[p[pidx++] - s]; } // fill code-like entries with r // f = 1 << (k - w); for(j = i >> w; j < z; j += f) { q[j].e = r.e; q[j].b = r.b; q[j].n = r.n; q[j].t = r.t; } // backwards increment the k-bit code i for(j = 1 << (k - 1); (i & j) != 0; j >>= 1) i ^= j; i ^= j; // backup over finished tables while((i & ((1 << w) - 1)) != x[h]) { w -= lx[h]; // don't need to update q h--; } } } /* return actual size of base table */ this.m = lx[1]; /* Return true (1) if we were given an incomplete table */ this.status = ((y != 0 && g != 1) ? 1 : 0); } /* end of constructor */ } /* routines (inflate) */ function zip_GET_BYTE() { if(zip_inflate_data.length == zip_inflate_pos) return -1; return zip_inflate_data.charCodeAt(zip_inflate_pos++) & 0xff; } function zip_NEEDBITS(n) { while(zip_bit_len < n) { zip_bit_buf |= zip_GET_BYTE() << zip_bit_len; zip_bit_len += 8; } } function zip_GETBITS(n) { return zip_bit_buf & zip_MASK_BITS[n]; } function zip_DUMPBITS(n) { zip_bit_buf >>= n; zip_bit_len -= n; } function zip_inflate_codes(buff, off, size) { /* inflate (decompress) the codes in a deflated (compressed) block. Return an error code or zero if it all goes ok. */ var e; // table entry flag/number of extra bits var t; // (zip_HuftNode) pointer to table entry var n; if(size == 0) return 0; // inflate the coded data n = 0; for(;;) { // do until end of block zip_NEEDBITS(zip_bl); t = zip_tl.list[zip_GETBITS(zip_bl)]; e = t.e; while(e > 16) { if(e == 99) return -1; zip_DUMPBITS(t.b); e -= 16; zip_NEEDBITS(e); t = t.t[zip_GETBITS(e)]; e = t.e; } zip_DUMPBITS(t.b); if(e == 16) { // then it's a literal zip_wp &= zip_WSIZE - 1; buff[off + n++] = zip_slide[zip_wp++] = t.n; if(n == size) return size; continue; } // exit if end of block if(e == 15) break; // it's an EOB or a length // get length of block to copy zip_NEEDBITS(e); zip_copy_leng = t.n + zip_GETBITS(e); zip_DUMPBITS(e); // decode distance of block to copy zip_NEEDBITS(zip_bd); t = zip_td.list[zip_GETBITS(zip_bd)]; e = t.e; while(e > 16) { if(e == 99) return -1; zip_DUMPBITS(t.b); e -= 16; zip_NEEDBITS(e); t = t.t[zip_GETBITS(e)]; e = t.e; } zip_DUMPBITS(t.b); zip_NEEDBITS(e); zip_copy_dist = zip_wp - t.n - zip_GETBITS(e); zip_DUMPBITS(e); // do the copy 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++]; } if(n == size) return size; } zip_method = -1; // done return n; } function zip_inflate_stored(buff, off, size) { /* "decompress" an inflated type 0 (stored) block. */ var n; // go to byte boundary n = zip_bit_len & 7; zip_DUMPBITS(n); // get the length and its complement zip_NEEDBITS(16); n = zip_GETBITS(16); zip_DUMPBITS(16); zip_NEEDBITS(16); if(n != ((~zip_bit_buf) & 0xffff)) return -1; // error in compressed data zip_DUMPBITS(16); // read and output the compressed data zip_copy_leng = n; n = 0; 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 return n; } function zip_inflate_fixed(buff, off, size) { /* decompress an inflated type 1 (fixed Huffman codes) block. We should either replace this with a custom decoder, or at least precompute the Huffman tables. */ // if first time, set up tables for fixed blocks if(zip_fixed_tl == null) { var i; // temporary variable var l = new Array(288); // length list for huft_build var h; // zip_HuftBuild // literal table for(i = 0; i < 144; i++) l[i] = 8; for(; i < 256; i++) l[i] = 9; for(; i < 280; i++) l[i] = 7; for(; i < 288; i++) // make a complete, but wrong code set l[i] = 8; zip_fixed_bl = 7; h = new zip_HuftBuild(l, 288, 257, zip_cplens, zip_cplext, zip_fixed_bl); if(h.status != 0) { alert("HufBuild error: "+h.status); return -1; } zip_fixed_tl = h.root; zip_fixed_bl = h.m; // distance table for(i = 0; i < 30; i++) // make an incomplete code set l[i] = 5; zip_fixed_bd = 5; h = new zip_HuftBuild(l, 30, 0, zip_cpdist, zip_cpdext, zip_fixed_bd); if(h.status > 1) { zip_fixed_tl = null; 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_start() { var i; 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; } 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(str) { var out, buff; var i, j; zip_inflate_start(); zip_inflate_data = str; zip_inflate_pos = 0; var last_zip_inflate_pos = -1; buff = new Array(1024); out = ""; while((i = zip_inflate_internal(buff, 0, buff.length)) > 0 && last_zip_inflate_pos != zip_inflate_pos) { last_zip_inflate_pos = zip_inflate_pos; for(j = 0; j < i; j++) out += String.fromCharCode(buff[j]); } zip_inflate_data = null; // G.C. return out; }