// Inflate.cs // ------------------------------------------------------------------ // // Copyright (c) 2009 Dino Chiesa and Microsoft Corporation. // All rights reserved. // // This code module is part of DotNetZip, a zipfile class library. // // ------------------------------------------------------------------ // // This code is licensed under the Microsoft Public License. // See the file License.txt for the license details. // More info on: http://dotnetzip.codeplex.com // // ------------------------------------------------------------------ // // last saved (in emacs): // Time-stamp: <2010-January-08 18:32:12> // // ------------------------------------------------------------------ // // This module defines classes for decompression. This code is derived // from the jzlib implementation of zlib, but significantly modified. // The object model is not the same, and many of the behaviors are // different. Nonetheless, in keeping with the license for jzlib, I am // reproducing the copyright to that code here. // // ------------------------------------------------------------------ // // Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are met: // // 1. Redistributions of source code must retain the above copyright notice, // this list of conditions and the following disclaimer. // // 2. Redistributions in binary form must reproduce the above copyright // notice, this list of conditions and the following disclaimer in // the documentation and/or other materials provided with the distribution. // // 3. The names of the authors may not be used to endorse or promote products // derived from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, // INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND // FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT, // INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT, // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, // OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, // EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. // // ----------------------------------------------------------------------- // // This program is based on zlib-1.1.3; credit to authors // Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu) // and contributors of zlib. // // ----------------------------------------------------------------------- using System; namespace BestHTTP.Decompression.Zlib { sealed class InflateBlocks { private const int MANY = 1440; // Table for deflate from PKZIP's appnote.txt. internal static readonly int[] border = new int[] { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 }; private enum InflateBlockMode { TYPE = 0, // get type bits (3, including end bit) LENS = 1, // get lengths for stored STORED = 2, // processing stored block TABLE = 3, // get table lengths BTREE = 4, // get bit lengths tree for a dynamic block DTREE = 5, // get length, distance trees for a dynamic block CODES = 6, // processing fixed or dynamic block DRY = 7, // output remaining window bytes DONE = 8, // finished last block, done BAD = 9, // ot a data error--stuck here } private InflateBlockMode mode; // current inflate_block mode internal int left; // if STORED, bytes left to copy internal int table; // table lengths (14 bits) internal int index; // index into blens (or border) internal int[] blens; // bit lengths of codes internal int[] bb = new int[1]; // bit length tree depth internal int[] tb = new int[1]; // bit length decoding tree internal InflateCodes codes = new InflateCodes(); // if CODES, current state internal int last; // true if this block is the last block internal ZlibCodec _codec; // pointer back to this zlib stream // mode independent information internal int bitk; // bits in bit buffer internal int bitb; // bit buffer internal int[] hufts; // single malloc for tree space internal byte[] window; // sliding window internal int end; // one byte after sliding window internal int readAt; // window read pointer internal int writeAt; // window write pointer internal System.Object checkfn; // check function internal uint check; // check on output internal InfTree inftree = new InfTree(); internal InflateBlocks(ZlibCodec codec, System.Object checkfn, int w) { _codec = codec; hufts = new int[MANY * 3]; window = new byte[w]; end = w; this.checkfn = checkfn; mode = InflateBlockMode.TYPE; Reset(); } internal uint Reset() { uint oldCheck = check; mode = InflateBlockMode.TYPE; bitk = 0; bitb = 0; readAt = writeAt = 0; if (checkfn != null) _codec._Adler32 = check = Adler.Adler32(0, null, 0, 0); return oldCheck; } internal int Process(int r) { int t; // temporary storage int b; // bit buffer int k; // bits in bit buffer int p; // input data pointer int n; // bytes available there int q; // output window write pointer int m; // bytes to end of window or read pointer // copy input/output information to locals (UPDATE macro restores) p = _codec.NextIn; n = _codec.AvailableBytesIn; b = bitb; k = bitk; q = writeAt; m = (int)(q < readAt ? readAt - q - 1 : end - q); // process input based on current state while (true) { switch (mode) { case InflateBlockMode.TYPE: while (k < (3)) { if (n != 0) { r = ZlibConstants.Z_OK; } else { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } n--; b |= (_codec.InputBuffer[p++] & 0xff) << k; k += 8; } t = (int)(b & 7); last = t & 1; switch ((uint)t >> 1) { case 0: // stored b >>= 3; k -= (3); t = k & 7; // go to byte boundary b >>= t; k -= t; mode = InflateBlockMode.LENS; // get length of stored block break; case 1: // fixed int[] bl = new int[1]; int[] bd = new int[1]; int[][] tl = new int[1][]; int[][] td = new int[1][]; InfTree.inflate_trees_fixed(bl, bd, tl, td, _codec); codes.Init(bl[0], bd[0], tl[0], 0, td[0], 0); b >>= 3; k -= 3; mode = InflateBlockMode.CODES; break; case 2: // dynamic b >>= 3; k -= 3; mode = InflateBlockMode.TABLE; break; case 3: // illegal b >>= 3; k -= 3; mode = InflateBlockMode.BAD; _codec.Message = "invalid block type"; r = ZlibConstants.Z_DATA_ERROR; bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } break; case InflateBlockMode.LENS: while (k < (32)) { if (n != 0) { r = ZlibConstants.Z_OK; } else { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } ; n--; b |= (_codec.InputBuffer[p++] & 0xff) << k; k += 8; } if ( ( ((~b)>>16) & 0xffff) != (b & 0xffff)) { mode = InflateBlockMode.BAD; _codec.Message = "invalid stored block lengths"; r = ZlibConstants.Z_DATA_ERROR; bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } left = (b & 0xffff); b = k = 0; // dump bits mode = left != 0 ? InflateBlockMode.STORED : (last != 0 ? InflateBlockMode.DRY : InflateBlockMode.TYPE); break; case InflateBlockMode.STORED: if (n == 0) { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } if (m == 0) { if (q == end && readAt != 0) { q = 0; m = (int)(q < readAt ? readAt - q - 1 : end - q); } if (m == 0) { writeAt = q; r = Flush(r); q = writeAt; m = (int)(q < readAt ? readAt - q - 1 : end - q); if (q == end && readAt != 0) { q = 0; m = (int)(q < readAt ? readAt - q - 1 : end - q); } if (m == 0) { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } } } r = ZlibConstants.Z_OK; t = left; if (t > n) t = n; if (t > m) t = m; Array.Copy(_codec.InputBuffer, p, window, q, t); p += t; n -= t; q += t; m -= t; if ((left -= t) != 0) break; mode = last != 0 ? InflateBlockMode.DRY : InflateBlockMode.TYPE; break; case InflateBlockMode.TABLE: while (k < (14)) { if (n != 0) { r = ZlibConstants.Z_OK; } else { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } n--; b |= (_codec.InputBuffer[p++] & 0xff) << k; k += 8; } table = t = (b & 0x3fff); if ((t & 0x1f) > 29 || ((t >> 5) & 0x1f) > 29) { mode = InflateBlockMode.BAD; _codec.Message = "too many length or distance symbols"; r = ZlibConstants.Z_DATA_ERROR; bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } t = 258 + (t & 0x1f) + ((t >> 5) & 0x1f); if (blens == null || blens.Length < t) { blens = new int[t]; } else { Array.Clear(blens, 0, t); // for (int i = 0; i < t; i++) // { // blens[i] = 0; // } } b >>= 14; k -= 14; index = 0; mode = InflateBlockMode.BTREE; goto case InflateBlockMode.BTREE; case InflateBlockMode.BTREE: while (index < 4 + (table >> 10)) { while (k < (3)) { if (n != 0) { r = ZlibConstants.Z_OK; } else { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } n--; b |= (_codec.InputBuffer[p++] & 0xff) << k; k += 8; } blens[border[index++]] = b & 7; b >>= 3; k -= 3; } while (index < 19) { blens[border[index++]] = 0; } bb[0] = 7; t = inftree.inflate_trees_bits(blens, bb, tb, hufts, _codec); if (t != ZlibConstants.Z_OK) { r = t; if (r == ZlibConstants.Z_DATA_ERROR) { blens = null; mode = InflateBlockMode.BAD; } bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } index = 0; mode = InflateBlockMode.DTREE; goto case InflateBlockMode.DTREE; case InflateBlockMode.DTREE: while (true) { t = table; if (!(index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f))) { break; } int i, j, c; t = bb[0]; while (k < t) { if (n != 0) { r = ZlibConstants.Z_OK; } else { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } n--; b |= (_codec.InputBuffer[p++] & 0xff) << k; k += 8; } t = hufts[(tb[0] + (b & InternalInflateConstants.InflateMask[t])) * 3 + 1]; c = hufts[(tb[0] + (b & InternalInflateConstants.InflateMask[t])) * 3 + 2]; if (c < 16) { b >>= t; k -= t; blens[index++] = c; } else { // c == 16..18 i = c == 18 ? 7 : c - 14; j = c == 18 ? 11 : 3; while (k < (t + i)) { if (n != 0) { r = ZlibConstants.Z_OK; } else { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } n--; b |= (_codec.InputBuffer[p++] & 0xff) << k; k += 8; } b >>= t; k -= t; j += (b & InternalInflateConstants.InflateMask[i]); b >>= i; k -= i; i = index; t = table; if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) || (c == 16 && i < 1)) { blens = null; mode = InflateBlockMode.BAD; _codec.Message = "invalid bit length repeat"; r = ZlibConstants.Z_DATA_ERROR; bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } c = (c == 16) ? blens[i-1] : 0; do { blens[i++] = c; } while (--j != 0); index = i; } } tb[0] = -1; { int[] bl = new int[] { 9 }; // must be <= 9 for lookahead assumptions int[] bd = new int[] { 6 }; // must be <= 9 for lookahead assumptions int[] tl = new int[1]; int[] td = new int[1]; t = table; t = inftree.inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f), blens, bl, bd, tl, td, hufts, _codec); if (t != ZlibConstants.Z_OK) { if (t == ZlibConstants.Z_DATA_ERROR) { blens = null; mode = InflateBlockMode.BAD; } r = t; bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } codes.Init(bl[0], bd[0], hufts, tl[0], hufts, td[0]); } mode = InflateBlockMode.CODES; goto case InflateBlockMode.CODES; case InflateBlockMode.CODES: bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; r = codes.Process(this, r); if (r != ZlibConstants.Z_STREAM_END) { return Flush(r); } r = ZlibConstants.Z_OK; p = _codec.NextIn; n = _codec.AvailableBytesIn; b = bitb; k = bitk; q = writeAt; m = (int)(q < readAt ? readAt - q - 1 : end - q); if (last == 0) { mode = InflateBlockMode.TYPE; break; } mode = InflateBlockMode.DRY; goto case InflateBlockMode.DRY; case InflateBlockMode.DRY: writeAt = q; r = Flush(r); q = writeAt; m = (int)(q < readAt ? readAt - q - 1 : end - q); if (readAt != writeAt) { bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } mode = InflateBlockMode.DONE; goto case InflateBlockMode.DONE; case InflateBlockMode.DONE: r = ZlibConstants.Z_STREAM_END; bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); case InflateBlockMode.BAD: r = ZlibConstants.Z_DATA_ERROR; bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); default: r = ZlibConstants.Z_STREAM_ERROR; bitb = b; bitk = k; _codec.AvailableBytesIn = n; _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; writeAt = q; return Flush(r); } } } internal void Free() { Reset(); window = null; hufts = null; } internal void SetDictionary(byte[] d, int start, int n) { Array.Copy(d, start, window, 0, n); readAt = writeAt = n; } // Returns true if inflate is currently at the end of a block generated // by Z_SYNC_FLUSH or Z_FULL_FLUSH. internal int SyncPoint() { return mode == InflateBlockMode.LENS ? 1 : 0; } // copy as much as possible from the sliding window to the output area internal int Flush(int r) { int nBytes; for (int pass=0; pass < 2; pass++) { if (pass==0) { // compute number of bytes to copy as far as end of window nBytes = (int)((readAt <= writeAt ? writeAt : end) - readAt); } else { // compute bytes to copy nBytes = writeAt - readAt; } // workitem 8870 if (nBytes == 0) { if (r == ZlibConstants.Z_BUF_ERROR) r = ZlibConstants.Z_OK; return r; } if (nBytes > _codec.AvailableBytesOut) nBytes = _codec.AvailableBytesOut; if (nBytes != 0 && r == ZlibConstants.Z_BUF_ERROR) r = ZlibConstants.Z_OK; // update counters _codec.AvailableBytesOut -= nBytes; _codec.TotalBytesOut += nBytes; // update check information if (checkfn != null) _codec._Adler32 = check = Adler.Adler32(check, window, readAt, nBytes); // copy as far as end of window Array.Copy(window, readAt, _codec.OutputBuffer, _codec.NextOut, nBytes); _codec.NextOut += nBytes; readAt += nBytes; // see if more to copy at beginning of window if (readAt == end && pass == 0) { // wrap pointers readAt = 0; if (writeAt == end) writeAt = 0; } else pass++; } // done return r; } } internal static class InternalInflateConstants { // And'ing with mask[n] masks the lower n bits internal static readonly int[] InflateMask = new int[] { 0x00000000, 0x00000001, 0x00000003, 0x00000007, 0x0000000f, 0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff }; } sealed class InflateCodes { // waiting for "i:"=input, // "o:"=output, // "x:"=nothing private const int START = 0; // x: set up for LEN private const int LEN = 1; // i: get length/literal/eob next private const int LENEXT = 2; // i: getting length extra (have base) private const int DIST = 3; // i: get distance next private const int DISTEXT = 4; // i: getting distance extra private const int COPY = 5; // o: copying bytes in window, waiting for space private const int LIT = 6; // o: got literal, waiting for output space private const int WASH = 7; // o: got eob, possibly still output waiting private const int END = 8; // x: got eob and all data flushed private const int BADCODE = 9; // x: got error internal int mode; // current inflate_codes mode // mode dependent information internal int len; internal int[] tree; // pointer into tree internal int tree_index = 0; internal int need; // bits needed internal int lit; // if EXT or COPY, where and how much internal int bitsToGet; // bits to get for extra internal int dist; // distance back to copy from internal byte lbits; // ltree bits decoded per branch internal byte dbits; // dtree bits decoder per branch internal int[] ltree; // literal/length/eob tree internal int ltree_index; // literal/length/eob tree internal int[] dtree; // distance tree internal int dtree_index; // distance tree internal InflateCodes() { } internal void Init(int bl, int bd, int[] tl, int tl_index, int[] td, int td_index) { mode = START; lbits = (byte)bl; dbits = (byte)bd; ltree = tl; ltree_index = tl_index; dtree = td; dtree_index = td_index; tree = null; } internal int Process(InflateBlocks blocks, int r) { int j; // temporary storage int tindex; // temporary pointer int e; // extra bits or operation int b = 0; // bit buffer int k = 0; // bits in bit buffer int p = 0; // input data pointer int n; // bytes available there int q; // output window write pointer int m; // bytes to end of window or read pointer int f; // pointer to copy strings from ZlibCodec z = blocks._codec; // copy input/output information to locals (UPDATE macro restores) p = z.NextIn; n = z.AvailableBytesIn; b = blocks.bitb; k = blocks.bitk; q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; // process input and output based on current state while (true) { switch (mode) { // waiting for "i:"=input, "o:"=output, "x:"=nothing case START: // x: set up for LEN if (m >= 258 && n >= 10) { blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; r = InflateFast(lbits, dbits, ltree, ltree_index, dtree, dtree_index, blocks, z); p = z.NextIn; n = z.AvailableBytesIn; b = blocks.bitb; k = blocks.bitk; q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; if (r != ZlibConstants.Z_OK) { mode = (r == ZlibConstants.Z_STREAM_END) ? WASH : BADCODE; break; } } need = lbits; tree = ltree; tree_index = ltree_index; mode = LEN; goto case LEN; case LEN: // i: get length/literal/eob next j = need; while (k < j) { if (n != 0) r = ZlibConstants.Z_OK; else { blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); } n--; b |= (z.InputBuffer[p++] & 0xff) << k; k += 8; } tindex = (tree_index + (b & InternalInflateConstants.InflateMask[j])) * 3; b >>= (tree[tindex + 1]); k -= (tree[tindex + 1]); e = tree[tindex]; if (e == 0) { // literal lit = tree[tindex + 2]; mode = LIT; break; } if ((e & 16) != 0) { // length bitsToGet = e & 15; len = tree[tindex + 2]; mode = LENEXT; break; } if ((e & 64) == 0) { // next table need = e; tree_index = tindex / 3 + tree[tindex + 2]; break; } if ((e & 32) != 0) { // end of block mode = WASH; break; } mode = BADCODE; // invalid code z.Message = "invalid literal/length code"; r = ZlibConstants.Z_DATA_ERROR; blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); case LENEXT: // i: getting length extra (have base) j = bitsToGet; while (k < j) { if (n != 0) r = ZlibConstants.Z_OK; else { blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); } n--; b |= (z.InputBuffer[p++] & 0xff) << k; k += 8; } len += (b & InternalInflateConstants.InflateMask[j]); b >>= j; k -= j; need = dbits; tree = dtree; tree_index = dtree_index; mode = DIST; goto case DIST; case DIST: // i: get distance next j = need; while (k < j) { if (n != 0) r = ZlibConstants.Z_OK; else { blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); } n--; b |= (z.InputBuffer[p++] & 0xff) << k; k += 8; } tindex = (tree_index + (b & InternalInflateConstants.InflateMask[j])) * 3; b >>= tree[tindex + 1]; k -= tree[tindex + 1]; e = (tree[tindex]); if ((e & 0x10) != 0) { // distance bitsToGet = e & 15; dist = tree[tindex + 2]; mode = DISTEXT; break; } if ((e & 64) == 0) { // next table need = e; tree_index = tindex / 3 + tree[tindex + 2]; break; } mode = BADCODE; // invalid code z.Message = "invalid distance code"; r = ZlibConstants.Z_DATA_ERROR; blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); case DISTEXT: // i: getting distance extra j = bitsToGet; while (k < j) { if (n != 0) r = ZlibConstants.Z_OK; else { blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); } n--; b |= (z.InputBuffer[p++] & 0xff) << k; k += 8; } dist += (b & InternalInflateConstants.InflateMask[j]); b >>= j; k -= j; mode = COPY; goto case COPY; case COPY: // o: copying bytes in window, waiting for space f = q - dist; while (f < 0) { // modulo window size-"while" instead f += blocks.end; // of "if" handles invalid distances } while (len != 0) { if (m == 0) { if (q == blocks.end && blocks.readAt != 0) { q = 0; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; } if (m == 0) { blocks.writeAt = q; r = blocks.Flush(r); q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; if (q == blocks.end && blocks.readAt != 0) { q = 0; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; } if (m == 0) { blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); } } } blocks.window[q++] = blocks.window[f++]; m--; if (f == blocks.end) f = 0; len--; } mode = START; break; case LIT: // o: got literal, waiting for output space if (m == 0) { if (q == blocks.end && blocks.readAt != 0) { q = 0; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; } if (m == 0) { blocks.writeAt = q; r = blocks.Flush(r); q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; if (q == blocks.end && blocks.readAt != 0) { q = 0; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; } if (m == 0) { blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); } } } r = ZlibConstants.Z_OK; blocks.window[q++] = (byte)lit; m--; mode = START; break; case WASH: // o: got eob, possibly more output if (k > 7) { // return unused byte, if any k -= 8; n++; p--; // can always return one } blocks.writeAt = q; r = blocks.Flush(r); q = blocks.writeAt; m = q < blocks.readAt ? blocks.readAt - q - 1 : blocks.end - q; if (blocks.readAt != blocks.writeAt) { blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); } mode = END; goto case END; case END: r = ZlibConstants.Z_STREAM_END; blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); case BADCODE: // x: got error r = ZlibConstants.Z_DATA_ERROR; blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); default: r = ZlibConstants.Z_STREAM_ERROR; blocks.bitb = b; blocks.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; blocks.writeAt = q; return blocks.Flush(r); } } } // Called with number of bytes left to write in window at least 258 // (the maximum string length) and number of input bytes available // at least ten. The ten bytes are six bytes for the longest length/ // distance pair plus four bytes for overloading the bit buffer. internal int InflateFast(int bl, int bd, int[] tl, int tl_index, int[] td, int td_index, InflateBlocks s, ZlibCodec z) { int t; // temporary pointer int[] tp; // temporary pointer int tp_index; // temporary pointer int e; // extra bits or operation int b; // bit buffer int k; // bits in bit buffer int p; // input data pointer int n; // bytes available there int q; // output window write pointer int m; // bytes to end of window or read pointer int ml; // mask for literal/length tree int md; // mask for distance tree int c; // bytes to copy int d; // distance back to copy from int r; // copy source pointer int tp_index_t_3; // (tp_index+t)*3 // load input, output, bit values p = z.NextIn; n = z.AvailableBytesIn; b = s.bitb; k = s.bitk; q = s.writeAt; m = q < s.readAt ? s.readAt - q - 1 : s.end - q; // initialize masks ml = InternalInflateConstants.InflateMask[bl]; md = InternalInflateConstants.InflateMask[bd]; // do until not enough input or output space for fast loop do { // assume called with m >= 258 && n >= 10 // get literal/length code while (k < (20)) { // max bits for literal/length code n--; b |= (z.InputBuffer[p++] & 0xff) << k; k += 8; } t = b & ml; tp = tl; tp_index = tl_index; tp_index_t_3 = (tp_index + t) * 3; if ((e = tp[tp_index_t_3]) == 0) { b >>= (tp[tp_index_t_3 + 1]); k -= (tp[tp_index_t_3 + 1]); s.window[q++] = (byte)tp[tp_index_t_3 + 2]; m--; continue; } do { b >>= (tp[tp_index_t_3 + 1]); k -= (tp[tp_index_t_3 + 1]); if ((e & 16) != 0) { e &= 15; c = tp[tp_index_t_3 + 2] + ((int)b & InternalInflateConstants.InflateMask[e]); b >>= e; k -= e; // decode distance base of block to copy while (k < 15) { // max bits for distance code n--; b |= (z.InputBuffer[p++] & 0xff) << k; k += 8; } t = b & md; tp = td; tp_index = td_index; tp_index_t_3 = (tp_index + t) * 3; e = tp[tp_index_t_3]; do { b >>= (tp[tp_index_t_3 + 1]); k -= (tp[tp_index_t_3 + 1]); if ((e & 16) != 0) { // get extra bits to add to distance base e &= 15; while (k < e) { // get extra bits (up to 13) n--; b |= (z.InputBuffer[p++] & 0xff) << k; k += 8; } d = tp[tp_index_t_3 + 2] + (b & InternalInflateConstants.InflateMask[e]); b >>= e; k -= e; // do the copy m -= c; if (q >= d) { // offset before dest // just copy r = q - d; if (q - r > 0 && 2 > (q - r)) { s.window[q++] = s.window[r++]; // minimum count is three, s.window[q++] = s.window[r++]; // so unroll loop a little c -= 2; } else { Array.Copy(s.window, r, s.window, q, 2); q += 2; r += 2; c -= 2; } } else { // else offset after destination r = q - d; do { r += s.end; // force pointer in window } while (r < 0); // covers invalid distances e = s.end - r; if (c > e) { // if source crosses, c -= e; // wrapped copy if (q - r > 0 && e > (q - r)) { do { s.window[q++] = s.window[r++]; } while (--e != 0); } else { Array.Copy(s.window, r, s.window, q, e); q += e; r += e; e = 0; } r = 0; // copy rest from start of window } } // copy all or what's left if (q - r > 0 && c > (q - r)) { do { s.window[q++] = s.window[r++]; } while (--c != 0); } else { Array.Copy(s.window, r, s.window, q, c); q += c; r += c; c = 0; } break; } else if ((e & 64) == 0) { t += tp[tp_index_t_3 + 2]; t += (b & InternalInflateConstants.InflateMask[e]); tp_index_t_3 = (tp_index + t) * 3; e = tp[tp_index_t_3]; } else { z.Message = "invalid distance code"; c = z.AvailableBytesIn - n; c = (k >> 3) < c ? k >> 3 : c; n += c; p -= c; k -= (c << 3); s.bitb = b; s.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; s.writeAt = q; return ZlibConstants.Z_DATA_ERROR; } } while (true); break; } if ((e & 64) == 0) { t += tp[tp_index_t_3 + 2]; t += (b & InternalInflateConstants.InflateMask[e]); tp_index_t_3 = (tp_index + t) * 3; if ((e = tp[tp_index_t_3]) == 0) { b >>= (tp[tp_index_t_3 + 1]); k -= (tp[tp_index_t_3 + 1]); s.window[q++] = (byte)tp[tp_index_t_3 + 2]; m--; break; } } else if ((e & 32) != 0) { c = z.AvailableBytesIn - n; c = (k >> 3) < c ? k >> 3 : c; n += c; p -= c; k -= (c << 3); s.bitb = b; s.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; s.writeAt = q; return ZlibConstants.Z_STREAM_END; } else { z.Message = "invalid literal/length code"; c = z.AvailableBytesIn - n; c = (k >> 3) < c ? k >> 3 : c; n += c; p -= c; k -= (c << 3); s.bitb = b; s.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; s.writeAt = q; return ZlibConstants.Z_DATA_ERROR; } } while (true); } while (m >= 258 && n >= 10); // not enough input or output--restore pointers and return c = z.AvailableBytesIn - n; c = (k >> 3) < c ? k >> 3 : c; n += c; p -= c; k -= (c << 3); s.bitb = b; s.bitk = k; z.AvailableBytesIn = n; z.TotalBytesIn += p - z.NextIn; z.NextIn = p; s.writeAt = q; return ZlibConstants.Z_OK; } } internal sealed class InflateManager { // preset dictionary flag in zlib header private const int PRESET_DICT = 0x20; private const int Z_DEFLATED = 8; private enum InflateManagerMode { METHOD = 0, // waiting for method byte FLAG = 1, // waiting for flag byte DICT4 = 2, // four dictionary check bytes to go DICT3 = 3, // three dictionary check bytes to go DICT2 = 4, // two dictionary check bytes to go DICT1 = 5, // one dictionary check byte to go DICT0 = 6, // waiting for inflateSetDictionary BLOCKS = 7, // decompressing blocks CHECK4 = 8, // four check bytes to go CHECK3 = 9, // three check bytes to go CHECK2 = 10, // two check bytes to go CHECK1 = 11, // one check byte to go DONE = 12, // finished check, done BAD = 13, // got an error--stay here } private InflateManagerMode mode; // current inflate mode internal ZlibCodec _codec; // pointer back to this zlib stream // mode dependent information internal int method; // if FLAGS, method byte // if CHECK, check values to compare internal uint computedCheck; // computed check value internal uint expectedCheck; // stream check value // if BAD, inflateSync's marker bytes count internal int marker; // mode independent information //internal int nowrap; // flag for no wrapper private bool _handleRfc1950HeaderBytes = true; internal bool HandleRfc1950HeaderBytes { get { return _handleRfc1950HeaderBytes; } set { _handleRfc1950HeaderBytes = value; } } internal int wbits; // log2(window size) (8..15, defaults to 15) internal InflateBlocks blocks; // current inflate_blocks state public InflateManager() { } public InflateManager(bool expectRfc1950HeaderBytes) { _handleRfc1950HeaderBytes = expectRfc1950HeaderBytes; } internal int Reset() { _codec.TotalBytesIn = _codec.TotalBytesOut = 0; _codec.Message = null; mode = HandleRfc1950HeaderBytes ? InflateManagerMode.METHOD : InflateManagerMode.BLOCKS; blocks.Reset(); return ZlibConstants.Z_OK; } internal int End() { if (blocks != null) blocks.Free(); blocks = null; return ZlibConstants.Z_OK; } internal int Initialize(ZlibCodec codec, int w) { _codec = codec; _codec.Message = null; blocks = null; // handle undocumented nowrap option (no zlib header or check) //nowrap = 0; //if (w < 0) //{ // w = - w; // nowrap = 1; //} // set window size if (w < 8 || w > 15) { End(); throw new ZlibException("Bad window size."); //return ZlibConstants.Z_STREAM_ERROR; } wbits = w; blocks = new InflateBlocks(codec, HandleRfc1950HeaderBytes ? this : null, 1 << w); // reset state Reset(); return ZlibConstants.Z_OK; } internal int Inflate(FlushType flush) { int b; if (_codec.InputBuffer == null) throw new ZlibException("InputBuffer is null. "); // int f = (flush == FlushType.Finish) // ? ZlibConstants.Z_BUF_ERROR // : ZlibConstants.Z_OK; // workitem 8870 int f = ZlibConstants.Z_OK; int r = ZlibConstants.Z_BUF_ERROR; while (true) { switch (mode) { case InflateManagerMode.METHOD: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; if (((method = _codec.InputBuffer[_codec.NextIn++]) & 0xf) != Z_DEFLATED) { mode = InflateManagerMode.BAD; _codec.Message = String.Format("unknown compression method (0x{0:X2})", method); marker = 5; // can't try inflateSync break; } if ((method >> 4) + 8 > wbits) { mode = InflateManagerMode.BAD; _codec.Message = String.Format("invalid window size ({0})", (method >> 4) + 8); marker = 5; // can't try inflateSync break; } mode = InflateManagerMode.FLAG; break; case InflateManagerMode.FLAG: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; b = (_codec.InputBuffer[_codec.NextIn++]) & 0xff; if ((((method << 8) + b) % 31) != 0) { mode = InflateManagerMode.BAD; _codec.Message = "incorrect header check"; marker = 5; // can't try inflateSync break; } mode = ((b & PRESET_DICT) == 0) ? InflateManagerMode.BLOCKS : InflateManagerMode.DICT4; break; case InflateManagerMode.DICT4: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; expectedCheck = (uint)((_codec.InputBuffer[_codec.NextIn++] << 24) & 0xff000000); mode = InflateManagerMode.DICT3; break; case InflateManagerMode.DICT3: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 16) & 0x00ff0000); mode = InflateManagerMode.DICT2; break; case InflateManagerMode.DICT2: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 8) & 0x0000ff00); mode = InflateManagerMode.DICT1; break; case InflateManagerMode.DICT1: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; expectedCheck += (uint)(_codec.InputBuffer[_codec.NextIn++] & 0x000000ff); _codec._Adler32 = expectedCheck; mode = InflateManagerMode.DICT0; return ZlibConstants.Z_NEED_DICT; case InflateManagerMode.DICT0: mode = InflateManagerMode.BAD; _codec.Message = "need dictionary"; marker = 0; // can try inflateSync return ZlibConstants.Z_STREAM_ERROR; case InflateManagerMode.BLOCKS: r = blocks.Process(r); if (r == ZlibConstants.Z_DATA_ERROR) { mode = InflateManagerMode.BAD; marker = 0; // can try inflateSync break; } if (r == ZlibConstants.Z_OK) r = f; if (r != ZlibConstants.Z_STREAM_END) return r; r = f; computedCheck = blocks.Reset(); if (!HandleRfc1950HeaderBytes) { mode = InflateManagerMode.DONE; return ZlibConstants.Z_STREAM_END; } mode = InflateManagerMode.CHECK4; break; case InflateManagerMode.CHECK4: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; expectedCheck = (uint)((_codec.InputBuffer[_codec.NextIn++] << 24) & 0xff000000); mode = InflateManagerMode.CHECK3; break; case InflateManagerMode.CHECK3: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 16) & 0x00ff0000); mode = InflateManagerMode.CHECK2; break; case InflateManagerMode.CHECK2: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; expectedCheck += (uint)((_codec.InputBuffer[_codec.NextIn++] << 8) & 0x0000ff00); mode = InflateManagerMode.CHECK1; break; case InflateManagerMode.CHECK1: if (_codec.AvailableBytesIn == 0) return r; r = f; _codec.AvailableBytesIn--; _codec.TotalBytesIn++; expectedCheck += (uint)(_codec.InputBuffer[_codec.NextIn++] & 0x000000ff); if (computedCheck != expectedCheck) { mode = InflateManagerMode.BAD; _codec.Message = "incorrect data check"; marker = 5; // can't try inflateSync break; } mode = InflateManagerMode.DONE; return ZlibConstants.Z_STREAM_END; case InflateManagerMode.DONE: return ZlibConstants.Z_STREAM_END; case InflateManagerMode.BAD: throw new ZlibException(String.Format("Bad state ({0})", _codec.Message)); default: throw new ZlibException("Stream error."); } } } internal int SetDictionary(byte[] dictionary) { int index = 0; int length = dictionary.Length; if (mode != InflateManagerMode.DICT0) throw new ZlibException("Stream error."); if (Adler.Adler32(1, dictionary, 0, dictionary.Length) != _codec._Adler32) { return ZlibConstants.Z_DATA_ERROR; } _codec._Adler32 = Adler.Adler32(0, null, 0, 0); if (length >= (1 << wbits)) { length = (1 << wbits) - 1; index = dictionary.Length - length; } blocks.SetDictionary(dictionary, index, length); mode = InflateManagerMode.BLOCKS; return ZlibConstants.Z_OK; } private static readonly byte[] mark = new byte[] { 0, 0, 0xff, 0xff }; internal int Sync() { int n; // number of bytes to look at int p; // pointer to bytes int m; // number of marker bytes found in a row long r, w; // temporaries to save total_in and total_out // set up if (mode != InflateManagerMode.BAD) { mode = InflateManagerMode.BAD; marker = 0; } if ((n = _codec.AvailableBytesIn) == 0) return ZlibConstants.Z_BUF_ERROR; p = _codec.NextIn; m = marker; // search while (n != 0 && m < 4) { if (_codec.InputBuffer[p] == mark[m]) { m++; } else if (_codec.InputBuffer[p] != 0) { m = 0; } else { m = 4 - m; } p++; n--; } // restore _codec.TotalBytesIn += p - _codec.NextIn; _codec.NextIn = p; _codec.AvailableBytesIn = n; marker = m; // return no joy or set up to restart on a new block if (m != 4) { return ZlibConstants.Z_DATA_ERROR; } r = _codec.TotalBytesIn; w = _codec.TotalBytesOut; Reset(); _codec.TotalBytesIn = r; _codec.TotalBytesOut = w; mode = InflateManagerMode.BLOCKS; return ZlibConstants.Z_OK; } // Returns true if inflate is currently at the end of a block generated // by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP // implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH // but removes the length bytes of the resulting empty stored block. When // decompressing, PPP checks that at the end of input packet, inflate is // waiting for these length bytes. internal int SyncPoint(ZlibCodec z) { return blocks.SyncPoint(); } } }