diff --git a/src/ImageSharp/Formats/Png/Zlib/Adler32.cs b/src/ImageSharp/Formats/Png/Zlib/Adler32.cs index a06983b9ed..f6f6edd124 100644 --- a/src/ImageSharp/Formats/Png/Zlib/Adler32.cs +++ b/src/ImageSharp/Formats/Png/Zlib/Adler32.cs @@ -1,4 +1,4 @@ -// Copyright (c) Six Labors and contributors. +// Copyright (c) Six Labors and contributors. // Licensed under the Apache License, Version 2.0. using System; @@ -133,8 +133,8 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib count -= n; while (--n >= 0) { - s1 = s1 + (uint)(data[offset++] & 0xff); - s2 = s2 + s1; + s1 += (uint)(data[offset++] & 0xff); + s2 += s1; } s1 %= Base; @@ -144,4 +144,4 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib this.checksum = (s2 << 16) | s1; } } -} \ No newline at end of file +} diff --git a/src/ImageSharp/Formats/Png/Zlib/Deflater.cs b/src/ImageSharp/Formats/Png/Zlib/Deflater.cs new file mode 100644 index 0000000000..3581125492 --- /dev/null +++ b/src/ImageSharp/Formats/Png/Zlib/Deflater.cs @@ -0,0 +1,610 @@ +// Copyright (c) Six Labors and contributors. +// Licensed under the Apache License, Version 2.0. + +// +using System; +using System.Collections.Generic; +using System.Text; + +namespace SixLabors.ImageSharp.Formats.Png.Zlib +{ + /// + /// This is the Deflater class. The deflater class compresses input + /// with the deflate algorithm described in RFC 1951. It has several + /// compression levels and three different strategies described below. + /// + /// This class is not thread safe. This is inherent in the API, due + /// to the split of deflate and setInput. + /// + /// author of the original java version : Jochen Hoenicke + /// + public class Deflater + { + #region Deflater Documentation + + /* + * The Deflater can do the following state transitions: + * + * (1) -> INIT_STATE ----> INIT_FINISHING_STATE ---. + * / | (2) (5) | + * / v (5) | + * (3)| SETDICT_STATE ---> SETDICT_FINISHING_STATE |(3) + * \ | (3) | ,--------' + * | | | (3) / + * v v (5) v v + * (1) -> BUSY_STATE ----> FINISHING_STATE + * | (6) + * v + * FINISHED_STATE + * \_____________________________________/ + * | (7) + * v + * CLOSED_STATE + * + * (1) If we should produce a header we start in INIT_STATE, otherwise + * we start in BUSY_STATE. + * (2) A dictionary may be set only when we are in INIT_STATE, then + * we change the state as indicated. + * (3) Whether a dictionary is set or not, on the first call of deflate + * we change to BUSY_STATE. + * (4) -- intentionally left blank -- :) + * (5) FINISHING_STATE is entered, when flush() is called to indicate that + * there is no more INPUT. There are also states indicating, that + * the header wasn't written yet. + * (6) FINISHED_STATE is entered, when everything has been flushed to the + * internal pending output buffer. + * (7) At any time (7) + * + */ + + #endregion Deflater Documentation + + #region Public Constants + + /// + /// The best and slowest compression level. This tries to find very + /// long and distant string repetitions. + /// + public const int BEST_COMPRESSION = 9; + + /// + /// The worst but fastest compression level. + /// + public const int BEST_SPEED = 1; + + /// + /// The default compression level. + /// + public const int DEFAULT_COMPRESSION = -1; + + /// + /// This level won't compress at all but output uncompressed blocks. + /// + public const int NO_COMPRESSION = 0; + + /// + /// The compression method. This is the only method supported so far. + /// There is no need to use this constant at all. + /// + public const int DEFLATED = 8; + + #endregion Public Constants + + #region Public Enum + + /// + /// Compression Level as an enum for safer use + /// + public enum CompressionLevel + { + /// + /// The best and slowest compression level. This tries to find very + /// long and distant string repetitions. + /// + BEST_COMPRESSION = Deflater.BEST_COMPRESSION, + + /// + /// The worst but fastest compression level. + /// + BEST_SPEED = Deflater.BEST_SPEED, + + /// + /// The default compression level. + /// + DEFAULT_COMPRESSION = Deflater.DEFAULT_COMPRESSION, + + /// + /// This level won't compress at all but output uncompressed blocks. + /// + NO_COMPRESSION = Deflater.NO_COMPRESSION, + + /// + /// The compression method. This is the only method supported so far. + /// There is no need to use this constant at all. + /// + DEFLATED = Deflater.DEFLATED + } + + #endregion Public Enum + + #region Local Constants + + private const int IS_SETDICT = 0x01; + private const int IS_FLUSHING = 0x04; + private const int IS_FINISHING = 0x08; + + private const int INIT_STATE = 0x00; + private const int SETDICT_STATE = 0x01; + + // private static int INIT_FINISHING_STATE = 0x08; + // private static int SETDICT_FINISHING_STATE = 0x09; + private const int BUSY_STATE = 0x10; + + private const int FLUSHING_STATE = 0x14; + private const int FINISHING_STATE = 0x1c; + private const int FINISHED_STATE = 0x1e; + private const int CLOSED_STATE = 0x7f; + + #endregion Local Constants + + #region Constructors + + /// + /// Creates a new deflater with default compression level. + /// + public Deflater() : this(DEFAULT_COMPRESSION, false) + { + } + + /// + /// Creates a new deflater with given compression level. + /// + /// + /// the compression level, a value between NO_COMPRESSION + /// and BEST_COMPRESSION, or DEFAULT_COMPRESSION. + /// + /// if lvl is out of range. + public Deflater(int level) : this(level, false) + { + } + + /// + /// Creates a new deflater with given compression level. + /// + /// + /// the compression level, a value between NO_COMPRESSION + /// and BEST_COMPRESSION. + /// + /// + /// true, if we should suppress the Zlib/RFC1950 header at the + /// beginning and the adler checksum at the end of the output. This is + /// useful for the GZIP/PKZIP formats. + /// + /// if lvl is out of range. + public Deflater(int level, bool noZlibHeaderOrFooter) + { + if (level == DEFAULT_COMPRESSION) + { + level = 6; + } + else if (level < NO_COMPRESSION || level > BEST_COMPRESSION) + { + throw new ArgumentOutOfRangeException(nameof(level)); + } + + pending = new DeflaterPending(); + engine = new DeflaterEngine(pending, noZlibHeaderOrFooter); + this.noZlibHeaderOrFooter = noZlibHeaderOrFooter; + SetStrategy(DeflateStrategy.Default); + SetLevel(level); + Reset(); + } + + #endregion Constructors + + /// + /// Resets the deflater. The deflater acts afterwards as if it was + /// just created with the same compression level and strategy as it + /// had before. + /// + public void Reset() + { + state = (noZlibHeaderOrFooter ? BUSY_STATE : INIT_STATE); + totalOut = 0; + pending.Reset(); + engine.Reset(); + } + + /// + /// Gets the current adler checksum of the data that was processed so far. + /// + public int Adler + { + get + { + return engine.Adler; + } + } + + /// + /// Gets the number of input bytes processed so far. + /// + public long TotalIn + { + get + { + return engine.TotalIn; + } + } + + /// + /// Gets the number of output bytes so far. + /// + public long TotalOut + { + get + { + return totalOut; + } + } + + /// + /// Flushes the current input block. Further calls to deflate() will + /// produce enough output to inflate everything in the current input + /// block. This is not part of Sun's JDK so I have made it package + /// private. It is used by DeflaterOutputStream to implement + /// flush(). + /// + public void Flush() + { + state |= IS_FLUSHING; + } + + /// + /// Finishes the deflater with the current input block. It is an error + /// to give more input after this method was called. This method must + /// be called to force all bytes to be flushed. + /// + public void Finish() + { + state |= (IS_FLUSHING | IS_FINISHING); + } + + /// + /// Returns true if the stream was finished and no more output bytes + /// are available. + /// + public bool IsFinished + { + get + { + return (state == FINISHED_STATE) && pending.IsFlushed; + } + } + + /// + /// Returns true, if the input buffer is empty. + /// You should then call setInput(). + /// NOTE: This method can also return true when the stream + /// was finished. + /// + public bool IsNeedingInput + { + get + { + return engine.NeedsInput(); + } + } + + /// + /// Sets the data which should be compressed next. This should be only + /// called when needsInput indicates that more input is needed. + /// If you call setInput when needsInput() returns false, the + /// previous input that is still pending will be thrown away. + /// The given byte array should not be changed, before needsInput() returns + /// true again. + /// This call is equivalent to setInput(input, 0, input.length). + /// + /// + /// the buffer containing the input data. + /// + /// + /// if the buffer was finished() or ended(). + /// + public void SetInput(byte[] input) + { + SetInput(input, 0, input.Length); + } + + /// + /// Sets the data which should be compressed next. This should be + /// only called when needsInput indicates that more input is needed. + /// The given byte array should not be changed, before needsInput() returns + /// true again. + /// + /// + /// the buffer containing the input data. + /// + /// + /// the start of the data. + /// + /// + /// the number of data bytes of input. + /// + /// + /// if the buffer was Finish()ed or if previous input is still pending. + /// + public void SetInput(byte[] input, int offset, int count) + { + if ((state & IS_FINISHING) != 0) + { + throw new InvalidOperationException("Finish() already called"); + } + engine.SetInput(input, offset, count); + } + + /// + /// Sets the compression level. There is no guarantee of the exact + /// position of the change, but if you call this when needsInput is + /// true the change of compression level will occur somewhere near + /// before the end of the so far given input. + /// + /// + /// the new compression level. + /// + public void SetLevel(int level) + { + if (level == DEFAULT_COMPRESSION) + { + level = 6; + } + else if (level < NO_COMPRESSION || level > BEST_COMPRESSION) + { + throw new ArgumentOutOfRangeException(nameof(level)); + } + + if (this.level != level) + { + this.level = level; + engine.SetLevel(level); + } + } + + /// + /// Get current compression level + /// + /// Returns the current compression level + public int GetLevel() + { + return level; + } + + /// + /// Sets the compression strategy. Strategy is one of + /// DEFAULT_STRATEGY, HUFFMAN_ONLY and FILTERED. For the exact + /// position where the strategy is changed, the same as for + /// SetLevel() applies. + /// + /// + /// The new compression strategy. + /// + public void SetStrategy(DeflateStrategy strategy) + { + engine.Strategy = strategy; + } + + /// + /// Deflates the current input block with to the given array. + /// + /// + /// The buffer where compressed data is stored + /// + /// + /// The number of compressed bytes added to the output, or 0 if either + /// IsNeedingInput() or IsFinished returns true or length is zero. + /// + public int Deflate(byte[] output) + { + return Deflate(output, 0, output.Length); + } + + /// + /// Deflates the current input block to the given array. + /// + /// + /// Buffer to store the compressed data. + /// + /// + /// Offset into the output array. + /// + /// + /// The maximum number of bytes that may be stored. + /// + /// + /// The number of compressed bytes added to the output, or 0 if either + /// needsInput() or finished() returns true or length is zero. + /// + /// + /// If Finish() was previously called. + /// + /// + /// If offset or length don't match the array length. + /// + public int Deflate(byte[] output, int offset, int length) + { + int origLength = length; + + if (state == CLOSED_STATE) + { + throw new InvalidOperationException("Deflater closed"); + } + + if (state < BUSY_STATE) + { + // output header + int header = (DEFLATED + + ((DeflaterConstants.MAX_WBITS - 8) << 4)) << 8; + int level_flags = (level - 1) >> 1; + if (level_flags < 0 || level_flags > 3) + { + level_flags = 3; + } + header |= level_flags << 6; + if ((state & IS_SETDICT) != 0) + { + // Dictionary was set + header |= DeflaterConstants.PRESET_DICT; + } + header += 31 - (header % 31); + + pending.WriteShortMSB(header); + if ((state & IS_SETDICT) != 0) + { + int chksum = engine.Adler; + engine.ResetAdler(); + pending.WriteShortMSB(chksum >> 16); + pending.WriteShortMSB(chksum & 0xffff); + } + + state = BUSY_STATE | (state & (IS_FLUSHING | IS_FINISHING)); + } + + for (; ; ) + { + int count = pending.Flush(output, offset, length); + offset += count; + totalOut += count; + length -= count; + + if (length == 0 || state == FINISHED_STATE) + { + break; + } + + if (!engine.Deflate((state & IS_FLUSHING) != 0, (state & IS_FINISHING) != 0)) + { + switch (state) + { + case BUSY_STATE: + // We need more input now + return origLength - length; + + case FLUSHING_STATE: + if (level != NO_COMPRESSION) + { + /* We have to supply some lookahead. 8 bit lookahead + * is needed by the zlib inflater, and we must fill + * the next byte, so that all bits are flushed. + */ + int neededbits = 8 + ((-pending.BitCount) & 7); + while (neededbits > 0) + { + /* write a static tree block consisting solely of + * an EOF: + */ + pending.WriteBits(2, 10); + neededbits -= 10; + } + } + state = BUSY_STATE; + break; + + case FINISHING_STATE: + pending.AlignToByte(); + + // Compressed data is complete. Write footer information if required. + if (!noZlibHeaderOrFooter) + { + int adler = engine.Adler; + pending.WriteShortMSB(adler >> 16); + pending.WriteShortMSB(adler & 0xffff); + } + state = FINISHED_STATE; + break; + } + } + } + return origLength - length; + } + + /// + /// Sets the dictionary which should be used in the deflate process. + /// This call is equivalent to setDictionary(dict, 0, dict.Length). + /// + /// + /// the dictionary. + /// + /// + /// if SetInput () or Deflate () were already called or another dictionary was already set. + /// + public void SetDictionary(byte[] dictionary) + { + SetDictionary(dictionary, 0, dictionary.Length); + } + + /// + /// Sets the dictionary which should be used in the deflate process. + /// The dictionary is a byte array containing strings that are + /// likely to occur in the data which should be compressed. The + /// dictionary is not stored in the compressed output, only a + /// checksum. To decompress the output you need to supply the same + /// dictionary again. + /// + /// + /// The dictionary data + /// + /// + /// The index where dictionary information commences. + /// + /// + /// The number of bytes in the dictionary. + /// + /// + /// If SetInput () or Deflate() were already called or another dictionary was already set. + /// + public void SetDictionary(byte[] dictionary, int index, int count) + { + if (state != INIT_STATE) + { + throw new InvalidOperationException(); + } + + state = SETDICT_STATE; + engine.SetDictionary(dictionary, index, count); + } + + #region Instance Fields + + /// + /// Compression level. + /// + private int level; + + /// + /// If true no Zlib/RFC1950 headers or footers are generated + /// + private bool noZlibHeaderOrFooter; + + /// + /// The current state. + /// + private int state; + + /// + /// The total bytes of output written. + /// + private long totalOut; + + /// + /// The pending output. + /// + private DeflaterPending pending; + + /// + /// The deflater engine. + /// + private DeflaterEngine engine; + + #endregion Instance Fields + } +} diff --git a/src/ImageSharp/Formats/Png/Zlib/DeflaterConstants.cs b/src/ImageSharp/Formats/Png/Zlib/DeflaterConstants.cs new file mode 100644 index 0000000000..67e8c6900b --- /dev/null +++ b/src/ImageSharp/Formats/Png/Zlib/DeflaterConstants.cs @@ -0,0 +1,151 @@ +// Copyright (c) Six Labors and contributors. +// Licensed under the Apache License, Version 2.0. + +// +using System; +using System.Collections.Generic; +using System.Text; + +namespace SixLabors.ImageSharp.Formats.Png.Zlib +{ + /// + /// This class contains constants used for deflation. + /// + public static class DeflaterConstants + { + /// + /// Set to true to enable debugging + /// + public const bool DEBUGGING = false; + + /// + /// Written to Zip file to identify a stored block + /// + public const int STORED_BLOCK = 0; + + /// + /// Identifies static tree in Zip file + /// + public const int STATIC_TREES = 1; + + /// + /// Identifies dynamic tree in Zip file + /// + public const int DYN_TREES = 2; + + /// + /// Header flag indicating a preset dictionary for deflation + /// + public const int PRESET_DICT = 0x20; + + /// + /// Sets internal buffer sizes for Huffman encoding + /// + public const int DEFAULT_MEM_LEVEL = 8; + + /// + /// Internal compression engine constant + /// + public const int MAX_MATCH = 258; + + /// + /// Internal compression engine constant + /// + public const int MIN_MATCH = 3; + + /// + /// Internal compression engine constant + /// + public const int MAX_WBITS = 15; + + /// + /// Internal compression engine constant + /// + public const int WSIZE = 1 << MAX_WBITS; + + /// + /// Internal compression engine constant + /// + public const int WMASK = WSIZE - 1; + + /// + /// Internal compression engine constant + /// + public const int HASH_BITS = DEFAULT_MEM_LEVEL + 7; + + /// + /// Internal compression engine constant + /// + public const int HASH_SIZE = 1 << HASH_BITS; + + /// + /// Internal compression engine constant + /// + public const int HASH_MASK = HASH_SIZE - 1; + + /// + /// Internal compression engine constant + /// + public const int HASH_SHIFT = (HASH_BITS + MIN_MATCH - 1) / MIN_MATCH; + + /// + /// Internal compression engine constant + /// + public const int MIN_LOOKAHEAD = MAX_MATCH + MIN_MATCH + 1; + + /// + /// Internal compression engine constant + /// + public const int MAX_DIST = WSIZE - MIN_LOOKAHEAD; + + /// + /// Internal compression engine constant + /// + public const int PENDING_BUF_SIZE = 1 << (DEFAULT_MEM_LEVEL + 8); + + /// + /// Internal compression engine constant + /// + public static int MAX_BLOCK_SIZE = Math.Min(65535, PENDING_BUF_SIZE - 5); + + /// + /// Internal compression engine constant + /// + public const int DEFLATE_STORED = 0; + + /// + /// Internal compression engine constant + /// + public const int DEFLATE_FAST = 1; + + /// + /// Internal compression engine constant + /// + public const int DEFLATE_SLOW = 2; + + /// + /// Internal compression engine constant + /// + public static int[] GOOD_LENGTH = { 0, 4, 4, 4, 4, 8, 8, 8, 32, 32 }; + + /// + /// Internal compression engine constant + /// + public static int[] MAX_LAZY = { 0, 4, 5, 6, 4, 16, 16, 32, 128, 258 }; + + /// + /// Internal compression engine constant + /// + public static int[] NICE_LENGTH = { 0, 8, 16, 32, 16, 32, 128, 128, 258, 258 }; + + /// + /// Internal compression engine constant + /// + public static int[] MAX_CHAIN = { 0, 4, 8, 32, 16, 32, 128, 256, 1024, 4096 }; + + /// + /// Internal compression engine constant + /// + public static int[] COMPR_FUNC = { 0, 1, 1, 1, 1, 2, 2, 2, 2, 2 }; + } +} diff --git a/src/ImageSharp/Formats/Png/Zlib/DeflaterEngine.cs b/src/ImageSharp/Formats/Png/Zlib/DeflaterEngine.cs new file mode 100644 index 0000000000..7ac5b6c69f --- /dev/null +++ b/src/ImageSharp/Formats/Png/Zlib/DeflaterEngine.cs @@ -0,0 +1,951 @@ +// Copyright (c) Six Labors and contributors. +// Licensed under the Apache License, Version 2.0. + +// +using System; +using System.Collections.Generic; +using System.Text; + +namespace SixLabors.ImageSharp.Formats.Png.Zlib +{ + /// + /// Strategies for deflater + /// + public enum DeflateStrategy + { + /// + /// The default strategy + /// + Default = 0, + + /// + /// This strategy will only allow longer string repetitions. It is + /// useful for random data with a small character set. + /// + Filtered = 1, + + /// + /// This strategy will not look for string repetitions at all. It + /// only encodes with Huffman trees (which means, that more common + /// characters get a smaller encoding. + /// + HuffmanOnly = 2 + } + + // DEFLATE ALGORITHM: + // + // The uncompressed stream is inserted into the window array. When + // the window array is full the first half is thrown away and the + // second half is copied to the beginning. + // + // The head array is a hash table. Three characters build a hash value + // and they the value points to the corresponding index in window of + // the last string with this hash. The prev array implements a + // linked list of matches with the same hash: prev[index & WMASK] points + // to the previous index with the same hash. + // + + /// + /// Low level compression engine for deflate algorithm which uses a 32K sliding window + /// with secondary compression from Huffman/Shannon-Fano codes. + /// + public class DeflaterEngine + { + #region Constants + + private const int TooFar = 4096; + + #endregion Constants + + #region Constructors + + /// + /// Construct instance with pending buffer + /// Adler calculation will be peformed + /// + /// + /// Pending buffer to use + /// + public DeflaterEngine(DeflaterPending pending) + : this(pending, false) + { + } + + + + /// + /// Construct instance with pending buffer + /// + /// + /// Pending buffer to use + /// + /// + /// If no adler calculation should be performed + /// + public DeflaterEngine(DeflaterPending pending, bool noAdlerCalculation) + { + this.pending = pending; + huffman = new DeflaterHuffman(pending); + if (!noAdlerCalculation) + adler = new Adler32(); + + window = new byte[2 * DeflaterConstants.WSIZE]; + head = new short[DeflaterConstants.HASH_SIZE]; + prev = new short[DeflaterConstants.WSIZE]; + + // We start at index 1, to avoid an implementation deficiency, that + // we cannot build a repeat pattern at index 0. + blockStart = strstart = 1; + } + + #endregion Constructors + + /// + /// Deflate drives actual compression of data + /// + /// True to flush input buffers + /// Finish deflation with the current input. + /// Returns true if progress has been made. + public bool Deflate(bool flush, bool finish) + { + bool progress; + do + { + FillWindow(); + bool canFlush = flush && (inputOff == inputEnd); + +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) { + Console.WriteLine("window: [" + blockStart + "," + strstart + "," + + lookahead + "], " + compressionFunction + "," + canFlush); + } +#endif + switch (compressionFunction) + { + case DeflaterConstants.DEFLATE_STORED: + progress = DeflateStored(canFlush, finish); + break; + + case DeflaterConstants.DEFLATE_FAST: + progress = DeflateFast(canFlush, finish); + break; + + case DeflaterConstants.DEFLATE_SLOW: + progress = DeflateSlow(canFlush, finish); + break; + + default: + throw new InvalidOperationException("unknown compressionFunction"); + } + } while (pending.IsFlushed && progress); // repeat while we have no pending output and progress was made + return progress; + } + + /// + /// Sets input data to be deflated. Should only be called when NeedsInput() + /// returns true + /// + /// The buffer containing input data. + /// The offset of the first byte of data. + /// The number of bytes of data to use as input. + public void SetInput(byte[] buffer, int offset, int count) + { + if (buffer == null) + { + throw new ArgumentNullException(nameof(buffer)); + } + + if (offset < 0) + { + throw new ArgumentOutOfRangeException(nameof(offset)); + } + + if (count < 0) + { + throw new ArgumentOutOfRangeException(nameof(count)); + } + + if (inputOff < inputEnd) + { + throw new InvalidOperationException("Old input was not completely processed"); + } + + int end = offset + count; + + /* We want to throw an ArrayIndexOutOfBoundsException early. The + * check is very tricky: it also handles integer wrap around. + */ + if ((offset > end) || (end > buffer.Length)) + { + throw new ArgumentOutOfRangeException(nameof(count)); + } + + inputBuf = buffer; + inputOff = offset; + inputEnd = end; + } + + /// + /// Determines if more input is needed. + /// + /// Return true if input is needed via SetInput + public bool NeedsInput() + { + return (inputEnd == inputOff); + } + + /// + /// Set compression dictionary + /// + /// The buffer containing the dictionary data + /// The offset in the buffer for the first byte of data + /// The length of the dictionary data. + public void SetDictionary(byte[] buffer, int offset, int length) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (strstart != 1) ) + { + throw new InvalidOperationException("strstart not 1"); + } +#endif + adler?.Update(new ArraySegment(buffer, offset, length)); + if (length < DeflaterConstants.MIN_MATCH) + { + return; + } + + if (length > DeflaterConstants.MAX_DIST) + { + offset += length - DeflaterConstants.MAX_DIST; + length = DeflaterConstants.MAX_DIST; + } + + System.Array.Copy(buffer, offset, window, strstart, length); + + UpdateHash(); + --length; + while (--length > 0) + { + InsertString(); + strstart++; + } + strstart += 2; + blockStart = strstart; + } + + /// + /// Reset internal state + /// + public void Reset() + { + huffman.Reset(); + adler?.Reset(); + blockStart = strstart = 1; + lookahead = 0; + totalIn = 0; + prevAvailable = false; + matchLen = DeflaterConstants.MIN_MATCH - 1; + + for (int i = 0; i < DeflaterConstants.HASH_SIZE; i++) + { + head[i] = 0; + } + + for (int i = 0; i < DeflaterConstants.WSIZE; i++) + { + prev[i] = 0; + } + } + + /// + /// Reset Adler checksum + /// + public void ResetAdler() + { + adler?.Reset(); + } + + /// + /// Get current value of Adler checksum + /// + public int Adler + { + get + { + return (adler != null) ? unchecked((int)adler.Value) : 0; + } + } + + /// + /// Total data processed + /// + public long TotalIn + { + get + { + return totalIn; + } + } + + /// + /// Get/set the deflate strategy + /// + public DeflateStrategy Strategy + { + get + { + return strategy; + } + set + { + strategy = value; + } + } + + /// + /// Set the deflate level (0-9) + /// + /// The value to set the level to. + public void SetLevel(int level) + { + if ((level < 0) || (level > 9)) + { + throw new ArgumentOutOfRangeException(nameof(level)); + } + + goodLength = DeflaterConstants.GOOD_LENGTH[level]; + max_lazy = DeflaterConstants.MAX_LAZY[level]; + niceLength = DeflaterConstants.NICE_LENGTH[level]; + max_chain = DeflaterConstants.MAX_CHAIN[level]; + + if (DeflaterConstants.COMPR_FUNC[level] != compressionFunction) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) { + Console.WriteLine("Change from " + compressionFunction + " to " + + DeflaterConstants.COMPR_FUNC[level]); + } +#endif + switch (compressionFunction) + { + case DeflaterConstants.DEFLATE_STORED: + if (strstart > blockStart) + { + huffman.FlushStoredBlock(window, blockStart, + strstart - blockStart, false); + blockStart = strstart; + } + UpdateHash(); + break; + + case DeflaterConstants.DEFLATE_FAST: + if (strstart > blockStart) + { + huffman.FlushBlock(window, blockStart, strstart - blockStart, + false); + blockStart = strstart; + } + break; + + case DeflaterConstants.DEFLATE_SLOW: + if (prevAvailable) + { + huffman.TallyLit(window[strstart - 1] & 0xff); + } + if (strstart > blockStart) + { + huffman.FlushBlock(window, blockStart, strstart - blockStart, false); + blockStart = strstart; + } + prevAvailable = false; + matchLen = DeflaterConstants.MIN_MATCH - 1; + break; + } + compressionFunction = DeflaterConstants.COMPR_FUNC[level]; + } + } + + /// + /// Fill the window + /// + public void FillWindow() + { + /* If the window is almost full and there is insufficient lookahead, + * move the upper half to the lower one to make room in the upper half. + */ + if (strstart >= DeflaterConstants.WSIZE + DeflaterConstants.MAX_DIST) + { + SlideWindow(); + } + + /* If there is not enough lookahead, but still some input left, + * read in the input + */ + if (lookahead < DeflaterConstants.MIN_LOOKAHEAD && inputOff < inputEnd) + { + int more = 2 * DeflaterConstants.WSIZE - lookahead - strstart; + + if (more > inputEnd - inputOff) + { + more = inputEnd - inputOff; + } + + System.Array.Copy(inputBuf, inputOff, window, strstart + lookahead, more); + adler?.Update(new ArraySegment(inputBuf, inputOff, more)); + + inputOff += more; + totalIn += more; + lookahead += more; + } + + if (lookahead >= DeflaterConstants.MIN_MATCH) + { + UpdateHash(); + } + } + + private void UpdateHash() + { + /* + if (DEBUGGING) { + Console.WriteLine("updateHash: "+strstart); + } + */ + ins_h = (window[strstart] << DeflaterConstants.HASH_SHIFT) ^ window[strstart + 1]; + } + + /// + /// Inserts the current string in the head hash and returns the previous + /// value for this hash. + /// + /// The previous hash value + private int InsertString() + { + short match; + int hash = ((ins_h << DeflaterConstants.HASH_SHIFT) ^ window[strstart + (DeflaterConstants.MIN_MATCH - 1)]) & DeflaterConstants.HASH_MASK; + +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) + { + if (hash != (((window[strstart] << (2*HASH_SHIFT)) ^ + (window[strstart + 1] << HASH_SHIFT) ^ + (window[strstart + 2])) & HASH_MASK)) { + throw new ImageFormatException("hash inconsistent: " + hash + "/" + +window[strstart] + "," + +window[strstart + 1] + "," + +window[strstart + 2] + "," + HASH_SHIFT); + } + } +#endif + prev[strstart & DeflaterConstants.WMASK] = match = head[hash]; + head[hash] = unchecked((short)strstart); + ins_h = hash; + return match & 0xffff; + } + + private void SlideWindow() + { + Array.Copy(window, DeflaterConstants.WSIZE, window, 0, DeflaterConstants.WSIZE); + matchStart -= DeflaterConstants.WSIZE; + strstart -= DeflaterConstants.WSIZE; + blockStart -= DeflaterConstants.WSIZE; + + // Slide the hash table (could be avoided with 32 bit values + // at the expense of memory usage). + for (int i = 0; i < DeflaterConstants.HASH_SIZE; ++i) + { + int m = head[i] & 0xffff; + head[i] = (short)(m >= DeflaterConstants.WSIZE ? (m - DeflaterConstants.WSIZE) : 0); + } + + // Slide the prev table. + for (int i = 0; i < DeflaterConstants.WSIZE; i++) + { + int m = prev[i] & 0xffff; + prev[i] = (short)(m >= DeflaterConstants.WSIZE ? (m - DeflaterConstants.WSIZE) : 0); + } + } + + /// + /// Find the best (longest) string in the window matching the + /// string starting at strstart. + /// + /// Preconditions: + /// + /// strstart + DeflaterConstants.MAX_MATCH <= window.length. + /// + /// + /// True if a match greater than the minimum length is found + private bool FindLongestMatch(int curMatch) + { + int match; + int scan = strstart; + // scanMax is the highest position that we can look at + int scanMax = scan + Math.Min(DeflaterConstants.MAX_MATCH, lookahead) - 1; + int limit = Math.Max(scan - DeflaterConstants.MAX_DIST, 0); + + byte[] window = this.window; + short[] prev = this.prev; + int chainLength = this.max_chain; + int niceLength = Math.Min(this.niceLength, lookahead); + + matchLen = Math.Max(matchLen, DeflaterConstants.MIN_MATCH - 1); + + if (scan + matchLen > scanMax) return false; + + byte scan_end1 = window[scan + matchLen - 1]; + byte scan_end = window[scan + matchLen]; + + // Do not waste too much time if we already have a good match: + if (matchLen >= this.goodLength) chainLength >>= 2; + + do + { + match = curMatch; + scan = strstart; + + if (window[match + matchLen] != scan_end + || window[match + matchLen - 1] != scan_end1 + || window[match] != window[scan] + || window[++match] != window[++scan]) + { + continue; + } + + // scan is set to strstart+1 and the comparison passed, so + // scanMax - scan is the maximum number of bytes we can compare. + // below we compare 8 bytes at a time, so first we compare + // (scanMax - scan) % 8 bytes, so the remainder is a multiple of 8 + + switch ((scanMax - scan) % 8) + { + case 1: + if (window[++scan] == window[++match]) break; + break; + + case 2: + if (window[++scan] == window[++match] + && window[++scan] == window[++match]) break; + break; + + case 3: + if (window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match]) break; + break; + + case 4: + if (window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match]) break; + break; + + case 5: + if (window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match]) break; + break; + + case 6: + if (window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match]) break; + break; + + case 7: + if (window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match]) break; + break; + } + + if (window[scan] == window[match]) + { + /* We check for insufficient lookahead only every 8th comparison; + * the 256th check will be made at strstart + 258 unless lookahead is + * exhausted first. + */ + do + { + if (scan == scanMax) + { + ++scan; // advance to first position not matched + ++match; + + break; + } + } + while (window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match] + && window[++scan] == window[++match]); + } + + if (scan - strstart > matchLen) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (ins_h == 0) ) + Console.Error.WriteLine("Found match: " + curMatch + "-" + (scan - strstart)); +#endif + + matchStart = curMatch; + matchLen = scan - strstart; + + if (matchLen >= niceLength) + break; + + scan_end1 = window[scan - 1]; + scan_end = window[scan]; + } + } while ((curMatch = (prev[curMatch & DeflaterConstants.WMASK] & 0xffff)) > limit && 0 != --chainLength); + + return matchLen >= DeflaterConstants.MIN_MATCH; + } + + private bool DeflateStored(bool flush, bool finish) + { + if (!flush && (lookahead == 0)) + { + return false; + } + + strstart += lookahead; + lookahead = 0; + + int storedLength = strstart - blockStart; + + if ((storedLength >= DeflaterConstants.MAX_BLOCK_SIZE) || // Block is full + (blockStart < DeflaterConstants.WSIZE && storedLength >= DeflaterConstants.MAX_DIST) || // Block may move out of window + flush) + { + bool lastBlock = finish; + if (storedLength > DeflaterConstants.MAX_BLOCK_SIZE) + { + storedLength = DeflaterConstants.MAX_BLOCK_SIZE; + lastBlock = false; + } + +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) + { + Console.WriteLine("storedBlock[" + storedLength + "," + lastBlock + "]"); + } +#endif + + huffman.FlushStoredBlock(window, blockStart, storedLength, lastBlock); + blockStart += storedLength; + return !(lastBlock || storedLength == 0); + } + return true; + } + + private bool DeflateFast(bool flush, bool finish) + { + if (lookahead < DeflaterConstants.MIN_LOOKAHEAD && !flush) + { + return false; + } + + while (lookahead >= DeflaterConstants.MIN_LOOKAHEAD || flush) + { + if (lookahead == 0) + { + // We are flushing everything + huffman.FlushBlock(window, blockStart, strstart - blockStart, finish); + blockStart = strstart; + return false; + } + + if (strstart > 2 * DeflaterConstants.WSIZE - DeflaterConstants.MIN_LOOKAHEAD) + { + /* slide window, as FindLongestMatch needs this. + * This should only happen when flushing and the window + * is almost full. + */ + SlideWindow(); + } + + int hashHead; + if (lookahead >= DeflaterConstants.MIN_MATCH && + (hashHead = InsertString()) != 0 && + strategy != DeflateStrategy.HuffmanOnly && + strstart - hashHead <= DeflaterConstants.MAX_DIST && + FindLongestMatch(hashHead)) + { + // longestMatch sets matchStart and matchLen +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) + { + for (int i = 0 ; i < matchLen; i++) { + if (window[strstart + i] != window[matchStart + i]) { + throw new ImageFormatException("Match failure"); + } + } + } +#endif + + bool full = huffman.TallyDist(strstart - matchStart, matchLen); + + lookahead -= matchLen; + if (matchLen <= max_lazy && lookahead >= DeflaterConstants.MIN_MATCH) + { + while (--matchLen > 0) + { + ++strstart; + InsertString(); + } + ++strstart; + } + else + { + strstart += matchLen; + if (lookahead >= DeflaterConstants.MIN_MATCH - 1) + { + UpdateHash(); + } + } + matchLen = DeflaterConstants.MIN_MATCH - 1; + if (!full) + { + continue; + } + } + else + { + // No match found + huffman.TallyLit(window[strstart] & 0xff); + ++strstart; + --lookahead; + } + + if (huffman.IsFull()) + { + bool lastBlock = finish && (lookahead == 0); + huffman.FlushBlock(window, blockStart, strstart - blockStart, lastBlock); + blockStart = strstart; + return !lastBlock; + } + } + return true; + } + + private bool DeflateSlow(bool flush, bool finish) + { + if (lookahead < DeflaterConstants.MIN_LOOKAHEAD && !flush) + { + return false; + } + + while (lookahead >= DeflaterConstants.MIN_LOOKAHEAD || flush) + { + if (lookahead == 0) + { + if (prevAvailable) + { + huffman.TallyLit(window[strstart - 1] & 0xff); + } + prevAvailable = false; + + // We are flushing everything +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && !flush) + { + throw new ImageFormatException("Not flushing, but no lookahead"); + } +#endif + huffman.FlushBlock(window, blockStart, strstart - blockStart, + finish); + blockStart = strstart; + return false; + } + + if (strstart >= 2 * DeflaterConstants.WSIZE - DeflaterConstants.MIN_LOOKAHEAD) + { + /* slide window, as FindLongestMatch needs this. + * This should only happen when flushing and the window + * is almost full. + */ + SlideWindow(); + } + + int prevMatch = matchStart; + int prevLen = matchLen; + if (lookahead >= DeflaterConstants.MIN_MATCH) + { + int hashHead = InsertString(); + + if (strategy != DeflateStrategy.HuffmanOnly && + hashHead != 0 && + strstart - hashHead <= DeflaterConstants.MAX_DIST && + FindLongestMatch(hashHead)) + { + // longestMatch sets matchStart and matchLen + + // Discard match if too small and too far away + if (matchLen <= 5 && (strategy == DeflateStrategy.Filtered || (matchLen == DeflaterConstants.MIN_MATCH && strstart - matchStart > TooFar))) + { + matchLen = DeflaterConstants.MIN_MATCH - 1; + } + } + } + + // previous match was better + if ((prevLen >= DeflaterConstants.MIN_MATCH) && (matchLen <= prevLen)) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) + { + for (int i = 0 ; i < matchLen; i++) { + if (window[strstart-1+i] != window[prevMatch + i]) + throw new ImageFormatException(); + } + } +#endif + huffman.TallyDist(strstart - 1 - prevMatch, prevLen); + prevLen -= 2; + do + { + strstart++; + lookahead--; + if (lookahead >= DeflaterConstants.MIN_MATCH) + { + InsertString(); + } + } while (--prevLen > 0); + + strstart++; + lookahead--; + prevAvailable = false; + matchLen = DeflaterConstants.MIN_MATCH - 1; + } + else + { + if (prevAvailable) + { + huffman.TallyLit(window[strstart - 1] & 0xff); + } + prevAvailable = true; + strstart++; + lookahead--; + } + + if (huffman.IsFull()) + { + int len = strstart - blockStart; + if (prevAvailable) + { + len--; + } + bool lastBlock = (finish && (lookahead == 0) && !prevAvailable); + huffman.FlushBlock(window, blockStart, len, lastBlock); + blockStart += len; + return !lastBlock; + } + } + return true; + } + + #region Instance Fields + + // Hash index of string to be inserted + private int ins_h; + + /// + /// Hashtable, hashing three characters to an index for window, so + /// that window[index]..window[index+2] have this hash code. + /// Note that the array should really be unsigned short, so you need + /// to and the values with 0xffff. + /// + private short[] head; + + /// + /// prev[index & WMASK] points to the previous index that has the + /// same hash code as the string starting at index. This way + /// entries with the same hash code are in a linked list. + /// Note that the array should really be unsigned short, so you need + /// to and the values with 0xffff. + /// + private short[] prev; + + private int matchStart; + + // Length of best match + private int matchLen; + + // Set if previous match exists + private bool prevAvailable; + + private int blockStart; + + /// + /// Points to the current character in the window. + /// + private int strstart; + + /// + /// lookahead is the number of characters starting at strstart in + /// window that are valid. + /// So window[strstart] until window[strstart+lookahead-1] are valid + /// characters. + /// + private int lookahead; + + /// + /// This array contains the part of the uncompressed stream that + /// is of relevance. The current character is indexed by strstart. + /// + private byte[] window; + + private DeflateStrategy strategy; + private int max_chain, max_lazy, niceLength, goodLength; + + /// + /// The current compression function. + /// + private int compressionFunction; + + /// + /// The input data for compression. + /// + private byte[] inputBuf; + + /// + /// The total bytes of input read. + /// + private long totalIn; + + /// + /// The offset into inputBuf, where input data starts. + /// + private int inputOff; + + /// + /// The end offset of the input data. + /// + private int inputEnd; + + private DeflaterPending pending; + private DeflaterHuffman huffman; + + /// + /// The adler checksum + /// + private Adler32 adler; + + #endregion Instance Fields + } +} diff --git a/src/ImageSharp/Formats/Png/Zlib/DeflaterHuffman.cs b/src/ImageSharp/Formats/Png/Zlib/DeflaterHuffman.cs new file mode 100644 index 0000000000..bf506d14c9 --- /dev/null +++ b/src/ImageSharp/Formats/Png/Zlib/DeflaterHuffman.cs @@ -0,0 +1,965 @@ +// Copyright (c) Six Labors and contributors. +// Licensed under the Apache License, Version 2.0. + +// +using System; +using System.Collections.Generic; +using System.Text; + +namespace SixLabors.ImageSharp.Formats.Png.Zlib +{ + /// + /// This is the DeflaterHuffman class. + /// + /// This class is not thread safe. This is inherent in the API, due + /// to the split of Deflate and SetInput. + /// + /// author of the original java version : Jochen Hoenicke + /// + public class DeflaterHuffman + { + private const int BUFSIZE = 1 << (DeflaterConstants.DEFAULT_MEM_LEVEL + 6); + private const int LITERAL_NUM = 286; + + // Number of distance codes + private const int DIST_NUM = 30; + + // Number of codes used to transfer bit lengths + private const int BITLEN_NUM = 19; + + // repeat previous bit length 3-6 times (2 bits of repeat count) + private const int REP_3_6 = 16; + + // repeat a zero length 3-10 times (3 bits of repeat count) + private const int REP_3_10 = 17; + + // repeat a zero length 11-138 times (7 bits of repeat count) + private const int REP_11_138 = 18; + + private const int EOF_SYMBOL = 256; + + // The lengths of the bit length codes are sent in order of decreasing + // probability, to avoid transmitting the lengths for unused bit length codes. + private static readonly int[] BL_ORDER = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 }; + + private static readonly byte[] bit4Reverse = { + 0, + 8, + 4, + 12, + 2, + 10, + 6, + 14, + 1, + 9, + 5, + 13, + 3, + 11, + 7, + 15 + }; + + private static short[] staticLCodes; + private static byte[] staticLLength; + private static short[] staticDCodes; + private static byte[] staticDLength; + + private class Tree + { + #region Instance Fields + + public short[] freqs; + + public byte[] length; + + public int minNumCodes; + + public int numCodes; + + private short[] codes; + private readonly int[] bl_counts; + private readonly int maxLength; + private DeflaterHuffman dh; + + #endregion Instance Fields + + #region Constructors + + public Tree(DeflaterHuffman dh, int elems, int minCodes, int maxLength) + { + this.dh = dh; + this.minNumCodes = minCodes; + this.maxLength = maxLength; + freqs = new short[elems]; + bl_counts = new int[maxLength]; + } + + #endregion Constructors + + /// + /// Resets the internal state of the tree + /// + public void Reset() + { + for (int i = 0; i < freqs.Length; i++) + { + freqs[i] = 0; + } + codes = null; + length = null; + } + + public void WriteSymbol(int code) + { + // if (DeflaterConstants.DEBUGGING) { + // freqs[code]--; + // // Console.Write("writeSymbol("+freqs.length+","+code+"): "); + // } + dh.pending.WriteBits(codes[code] & 0xffff, length[code]); + } + + /// + /// Check that all frequencies are zero + /// + /// + /// At least one frequency is non-zero + /// + public void CheckEmpty() + { + bool empty = true; + for (int i = 0; i < freqs.Length; i++) + { + empty &= freqs[i] == 0; + } + + if (!empty) + { + throw new ImageFormatException("!Empty"); + } + } + + /// + /// Set static codes and length + /// + /// new codes + /// length for new codes + public void SetStaticCodes(short[] staticCodes, byte[] staticLengths) + { + codes = staticCodes; + length = staticLengths; + } + + /// + /// Build dynamic codes and lengths + /// + public void BuildCodes() + { + int numSymbols = freqs.Length; + int[] nextCode = new int[maxLength]; + int code = 0; + + codes = new short[freqs.Length]; + + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("buildCodes: "+freqs.Length); + // } + + for (int bits = 0; bits < maxLength; bits++) + { + nextCode[bits] = code; + code += bl_counts[bits] << (15 - bits); + + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("bits: " + ( bits + 1) + " count: " + bl_counts[bits] + // +" nextCode: "+code); + // } + } + +#if DebugDeflation + if ( DeflaterConstants.DEBUGGING && (code != 65536) ) + { + throw new ImageFormatException("Inconsistent bl_counts!"); + } +#endif + for (int i = 0; i < numCodes; i++) + { + int bits = length[i]; + if (bits > 0) + { + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("codes["+i+"] = rev(" + nextCode[bits-1]+"), + // +bits); + // } + + codes[i] = BitReverse(nextCode[bits - 1]); + nextCode[bits - 1] += 1 << (16 - bits); + } + } + } + + public void BuildTree() + { + int numSymbols = freqs.Length; + + /* heap is a priority queue, sorted by frequency, least frequent + * nodes first. The heap is a binary tree, with the property, that + * the parent node is smaller than both child nodes. This assures + * that the smallest node is the first parent. + * + * The binary tree is encoded in an array: 0 is root node and + * the nodes 2*n+1, 2*n+2 are the child nodes of node n. + */ + int[] heap = new int[numSymbols]; + int heapLen = 0; + int maxCode = 0; + for (int n = 0; n < numSymbols; n++) + { + int freq = freqs[n]; + if (freq != 0) + { + // Insert n into heap + int pos = heapLen++; + int ppos; + while (pos > 0 && freqs[heap[ppos = (pos - 1) / 2]] > freq) + { + heap[pos] = heap[ppos]; + pos = ppos; + } + heap[pos] = n; + + maxCode = n; + } + } + + /* We could encode a single literal with 0 bits but then we + * don't see the literals. Therefore we force at least two + * literals to avoid this case. We don't care about order in + * this case, both literals get a 1 bit code. + */ + while (heapLen < 2) + { + int node = maxCode < 2 ? ++maxCode : 0; + heap[heapLen++] = node; + } + + numCodes = Math.Max(maxCode + 1, minNumCodes); + + int numLeafs = heapLen; + int[] childs = new int[4 * heapLen - 2]; + int[] values = new int[2 * heapLen - 1]; + int numNodes = numLeafs; + for (int i = 0; i < heapLen; i++) + { + int node = heap[i]; + childs[2 * i] = node; + childs[2 * i + 1] = -1; + values[i] = freqs[node] << 8; + heap[i] = i; + } + + /* Construct the Huffman tree by repeatedly combining the least two + * frequent nodes. + */ + do + { + int first = heap[0]; + int last = heap[--heapLen]; + + // Propagate the hole to the leafs of the heap + int ppos = 0; + int path = 1; + + while (path < heapLen) + { + if (path + 1 < heapLen && values[heap[path]] > values[heap[path + 1]]) + { + path++; + } + + heap[ppos] = heap[path]; + ppos = path; + path = path * 2 + 1; + } + + /* Now propagate the last element down along path. Normally + * it shouldn't go too deep. + */ + int lastVal = values[last]; + while ((path = ppos) > 0 && values[heap[ppos = (path - 1) / 2]] > lastVal) + { + heap[path] = heap[ppos]; + } + heap[path] = last; + + int second = heap[0]; + + // Create a new node father of first and second + last = numNodes++; + childs[2 * last] = first; + childs[2 * last + 1] = second; + int mindepth = Math.Min(values[first] & 0xff, values[second] & 0xff); + values[last] = lastVal = values[first] + values[second] - mindepth + 1; + + // Again, propagate the hole to the leafs + ppos = 0; + path = 1; + + while (path < heapLen) + { + if (path + 1 < heapLen && values[heap[path]] > values[heap[path + 1]]) + { + path++; + } + + heap[ppos] = heap[path]; + ppos = path; + path = ppos * 2 + 1; + } + + // Now propagate the new element down along path + while ((path = ppos) > 0 && values[heap[ppos = (path - 1) / 2]] > lastVal) + { + heap[path] = heap[ppos]; + } + heap[path] = last; + } while (heapLen > 1); + + if (heap[0] != childs.Length / 2 - 1) + { + throw new ImageFormatException("Heap invariant violated"); + } + + BuildLength(childs); + } + + /// + /// Get encoded length + /// + /// Encoded length, the sum of frequencies * lengths + public int GetEncodedLength() + { + int len = 0; + for (int i = 0; i < freqs.Length; i++) + { + len += freqs[i] * length[i]; + } + return len; + } + + /// + /// Scan a literal or distance tree to determine the frequencies of the codes + /// in the bit length tree. + /// + public void CalcBLFreq(Tree blTree) + { + int max_count; /* max repeat count */ + int min_count; /* min repeat count */ + int count; /* repeat count of the current code */ + int curlen = -1; /* length of current code */ + + int i = 0; + while (i < numCodes) + { + count = 1; + int nextlen = length[i]; + if (nextlen == 0) + { + max_count = 138; + min_count = 3; + } + else + { + max_count = 6; + min_count = 3; + if (curlen != nextlen) + { + blTree.freqs[nextlen]++; + count = 0; + } + } + curlen = nextlen; + i++; + + while (i < numCodes && curlen == length[i]) + { + i++; + if (++count >= max_count) + { + break; + } + } + + if (count < min_count) + { + blTree.freqs[curlen] += (short)count; + } + else if (curlen != 0) + { + blTree.freqs[REP_3_6]++; + } + else if (count <= 10) + { + blTree.freqs[REP_3_10]++; + } + else + { + blTree.freqs[REP_11_138]++; + } + } + } + + /// + /// Write tree values + /// + /// Tree to write + public void WriteTree(Tree blTree) + { + int max_count; // max repeat count + int min_count; // min repeat count + int count; // repeat count of the current code + int curlen = -1; // length of current code + + int i = 0; + while (i < numCodes) + { + count = 1; + int nextlen = length[i]; + if (nextlen == 0) + { + max_count = 138; + min_count = 3; + } + else + { + max_count = 6; + min_count = 3; + if (curlen != nextlen) + { + blTree.WriteSymbol(nextlen); + count = 0; + } + } + curlen = nextlen; + i++; + + while (i < numCodes && curlen == length[i]) + { + i++; + if (++count >= max_count) + { + break; + } + } + + if (count < min_count) + { + while (count-- > 0) + { + blTree.WriteSymbol(curlen); + } + } + else if (curlen != 0) + { + blTree.WriteSymbol(REP_3_6); + dh.pending.WriteBits(count - 3, 2); + } + else if (count <= 10) + { + blTree.WriteSymbol(REP_3_10); + dh.pending.WriteBits(count - 3, 3); + } + else + { + blTree.WriteSymbol(REP_11_138); + dh.pending.WriteBits(count - 11, 7); + } + } + } + + private void BuildLength(int[] childs) + { + this.length = new byte[freqs.Length]; + int numNodes = childs.Length / 2; + int numLeafs = (numNodes + 1) / 2; + int overflow = 0; + + for (int i = 0; i < maxLength; i++) + { + bl_counts[i] = 0; + } + + // First calculate optimal bit lengths + int[] lengths = new int[numNodes]; + lengths[numNodes - 1] = 0; + + for (int i = numNodes - 1; i >= 0; i--) + { + if (childs[2 * i + 1] != -1) + { + int bitLength = lengths[i] + 1; + if (bitLength > maxLength) + { + bitLength = maxLength; + overflow++; + } + lengths[childs[2 * i]] = lengths[childs[2 * i + 1]] = bitLength; + } + else + { + // A leaf node + int bitLength = lengths[i]; + bl_counts[bitLength - 1]++; + this.length[childs[2 * i]] = (byte)lengths[i]; + } + } + + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("Tree "+freqs.Length+" lengths:"); + // for (int i=0; i < numLeafs; i++) { + // //Console.WriteLine("Node "+childs[2*i]+" freq: "+freqs[childs[2*i]] + // + " len: "+length[childs[2*i]]); + // } + // } + + if (overflow == 0) + { + return; + } + + int incrBitLen = maxLength - 1; + do + { + // Find the first bit length which could increase: + while (bl_counts[--incrBitLen] == 0) + { + } + + // Move this node one down and remove a corresponding + // number of overflow nodes. + do + { + bl_counts[incrBitLen]--; + bl_counts[++incrBitLen]++; + overflow -= 1 << (maxLength - 1 - incrBitLen); + } while (overflow > 0 && incrBitLen < maxLength - 1); + } while (overflow > 0); + + /* We may have overshot above. Move some nodes from maxLength to + * maxLength-1 in that case. + */ + bl_counts[maxLength - 1] += overflow; + bl_counts[maxLength - 2] -= overflow; + + /* Now recompute all bit lengths, scanning in increasing + * frequency. It is simpler to reconstruct all lengths instead of + * fixing only the wrong ones. This idea is taken from 'ar' + * written by Haruhiko Okumura. + * + * The nodes were inserted with decreasing frequency into the childs + * array. + */ + int nodePtr = 2 * numLeafs; + for (int bits = maxLength; bits != 0; bits--) + { + int n = bl_counts[bits - 1]; + while (n > 0) + { + int childPtr = 2 * childs[nodePtr++]; + if (childs[childPtr + 1] == -1) + { + // We found another leaf + length[childs[childPtr]] = (byte)bits; + n--; + } + } + } + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("*** After overflow elimination. ***"); + // for (int i=0; i < numLeafs; i++) { + // //Console.WriteLine("Node "+childs[2*i]+" freq: "+freqs[childs[2*i]] + // + " len: "+length[childs[2*i]]); + // } + // } + } + } + + #region Instance Fields + + /// + /// Pending buffer to use + /// + public DeflaterPending pending; + + private Tree literalTree; + private Tree distTree; + private Tree blTree; + + // Buffer for distances + private short[] d_buf; + + private byte[] l_buf; + private int last_lit; + private int extra_bits; + + #endregion Instance Fields + + static DeflaterHuffman() + { + // See RFC 1951 3.2.6 + // Literal codes + staticLCodes = new short[LITERAL_NUM]; + staticLLength = new byte[LITERAL_NUM]; + + int i = 0; + while (i < 144) + { + staticLCodes[i] = BitReverse((0x030 + i) << 8); + staticLLength[i++] = 8; + } + + while (i < 256) + { + staticLCodes[i] = BitReverse((0x190 - 144 + i) << 7); + staticLLength[i++] = 9; + } + + while (i < 280) + { + staticLCodes[i] = BitReverse((0x000 - 256 + i) << 9); + staticLLength[i++] = 7; + } + + while (i < LITERAL_NUM) + { + staticLCodes[i] = BitReverse((0x0c0 - 280 + i) << 8); + staticLLength[i++] = 8; + } + + // Distance codes + staticDCodes = new short[DIST_NUM]; + staticDLength = new byte[DIST_NUM]; + for (i = 0; i < DIST_NUM; i++) + { + staticDCodes[i] = BitReverse(i << 11); + staticDLength[i] = 5; + } + } + + /// + /// Construct instance with pending buffer + /// + /// Pending buffer to use + public DeflaterHuffman(DeflaterPending pending) + { + this.pending = pending; + + literalTree = new Tree(this, LITERAL_NUM, 257, 15); + distTree = new Tree(this, DIST_NUM, 1, 15); + blTree = new Tree(this, BITLEN_NUM, 4, 7); + + d_buf = new short[BUFSIZE]; + l_buf = new byte[BUFSIZE]; + } + + /// + /// Reset internal state + /// + public void Reset() + { + last_lit = 0; + extra_bits = 0; + literalTree.Reset(); + distTree.Reset(); + blTree.Reset(); + } + + /// + /// Write all trees to pending buffer + /// + /// The number/rank of treecodes to send. + public void SendAllTrees(int blTreeCodes) + { + blTree.BuildCodes(); + literalTree.BuildCodes(); + distTree.BuildCodes(); + pending.WriteBits(literalTree.numCodes - 257, 5); + pending.WriteBits(distTree.numCodes - 1, 5); + pending.WriteBits(blTreeCodes - 4, 4); + for (int rank = 0; rank < blTreeCodes; rank++) + { + pending.WriteBits(blTree.length[BL_ORDER[rank]], 3); + } + literalTree.WriteTree(blTree); + distTree.WriteTree(blTree); + +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) { + blTree.CheckEmpty(); + } +#endif + } + + /// + /// Compress current buffer writing data to pending buffer + /// + public void CompressBlock() + { + for (int i = 0; i < last_lit; i++) + { + int litlen = l_buf[i] & 0xff; + int dist = d_buf[i]; + if (dist-- != 0) + { + // if (DeflaterConstants.DEBUGGING) { + // Console.Write("["+(dist+1)+","+(litlen+3)+"]: "); + // } + + int lc = Lcode(litlen); + literalTree.WriteSymbol(lc); + + int bits = (lc - 261) / 4; + if (bits > 0 && bits <= 5) + { + pending.WriteBits(litlen & ((1 << bits) - 1), bits); + } + + int dc = Dcode(dist); + distTree.WriteSymbol(dc); + + bits = dc / 2 - 1; + if (bits > 0) + { + pending.WriteBits(dist & ((1 << bits) - 1), bits); + } + } + else + { + // if (DeflaterConstants.DEBUGGING) { + // if (litlen > 32 && litlen < 127) { + // Console.Write("("+(char)litlen+"): "); + // } else { + // Console.Write("{"+litlen+"}: "); + // } + // } + literalTree.WriteSymbol(litlen); + } + } + +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) { + Console.Write("EOF: "); + } +#endif + literalTree.WriteSymbol(EOF_SYMBOL); + +#if DebugDeflation + if (DeflaterConstants.DEBUGGING) { + literalTree.CheckEmpty(); + distTree.CheckEmpty(); + } +#endif + } + + /// + /// Flush block to output with no compression + /// + /// Data to write + /// Index of first byte to write + /// Count of bytes to write + /// True if this is the last block + public void FlushStoredBlock(byte[] stored, int storedOffset, int storedLength, bool lastBlock) + { +#if DebugDeflation + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("Flushing stored block "+ storedLength); + // } +#endif + pending.WriteBits((DeflaterConstants.STORED_BLOCK << 1) + (lastBlock ? 1 : 0), 3); + pending.AlignToByte(); + pending.WriteShort(storedLength); + pending.WriteShort(~storedLength); + pending.WriteBlock(stored, storedOffset, storedLength); + Reset(); + } + + /// + /// Flush block to output with compression + /// + /// Data to flush + /// Index of first byte to flush + /// Count of bytes to flush + /// True if this is the last block + public void FlushBlock(byte[] stored, int storedOffset, int storedLength, bool lastBlock) + { + literalTree.freqs[EOF_SYMBOL]++; + + // Build trees + literalTree.BuildTree(); + distTree.BuildTree(); + + // Calculate bitlen frequency + literalTree.CalcBLFreq(blTree); + distTree.CalcBLFreq(blTree); + + // Build bitlen tree + blTree.BuildTree(); + + int blTreeCodes = 4; + for (int i = 18; i > blTreeCodes; i--) + { + if (blTree.length[BL_ORDER[i]] > 0) + { + blTreeCodes = i + 1; + } + } + int opt_len = 14 + blTreeCodes * 3 + blTree.GetEncodedLength() + + literalTree.GetEncodedLength() + distTree.GetEncodedLength() + + extra_bits; + + int static_len = extra_bits; + for (int i = 0; i < LITERAL_NUM; i++) + { + static_len += literalTree.freqs[i] * staticLLength[i]; + } + for (int i = 0; i < DIST_NUM; i++) + { + static_len += distTree.freqs[i] * staticDLength[i]; + } + if (opt_len >= static_len) + { + // Force static trees + opt_len = static_len; + } + + if (storedOffset >= 0 && storedLength + 4 < opt_len >> 3) + { + // Store Block + + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("Storing, since " + storedLength + " < " + opt_len + // + " <= " + static_len); + // } + FlushStoredBlock(stored, storedOffset, storedLength, lastBlock); + } + else if (opt_len == static_len) + { + // Encode with static tree + pending.WriteBits((DeflaterConstants.STATIC_TREES << 1) + (lastBlock ? 1 : 0), 3); + literalTree.SetStaticCodes(staticLCodes, staticLLength); + distTree.SetStaticCodes(staticDCodes, staticDLength); + CompressBlock(); + Reset(); + } + else + { + // Encode with dynamic tree + pending.WriteBits((DeflaterConstants.DYN_TREES << 1) + (lastBlock ? 1 : 0), 3); + SendAllTrees(blTreeCodes); + CompressBlock(); + Reset(); + } + } + + /// + /// Get value indicating if internal buffer is full + /// + /// true if buffer is full + public bool IsFull() + { + return last_lit >= BUFSIZE; + } + + /// + /// Add literal to buffer + /// + /// Literal value to add to buffer. + /// Value indicating internal buffer is full + public bool TallyLit(int literal) + { + // if (DeflaterConstants.DEBUGGING) { + // if (lit > 32 && lit < 127) { + // //Console.WriteLine("("+(char)lit+")"); + // } else { + // //Console.WriteLine("{"+lit+"}"); + // } + // } + d_buf[last_lit] = 0; + l_buf[last_lit++] = (byte)literal; + literalTree.freqs[literal]++; + return IsFull(); + } + + /// + /// Add distance code and length to literal and distance trees + /// + /// Distance code + /// Length + /// Value indicating if internal buffer is full + public bool TallyDist(int distance, int length) + { + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("[" + distance + "," + length + "]"); + // } + + d_buf[last_lit] = (short)distance; + l_buf[last_lit++] = (byte)(length - 3); + + int lc = Lcode(length - 3); + literalTree.freqs[lc]++; + if (lc >= 265 && lc < 285) + { + extra_bits += (lc - 261) / 4; + } + + int dc = Dcode(distance - 1); + distTree.freqs[dc]++; + if (dc >= 4) + { + extra_bits += dc / 2 - 1; + } + return IsFull(); + } + + /// + /// Reverse the bits of a 16 bit value. + /// + /// Value to reverse bits + /// Value with bits reversed + public static short BitReverse(int toReverse) + { + return (short)(bit4Reverse[toReverse & 0xF] << 12 | + bit4Reverse[(toReverse >> 4) & 0xF] << 8 | + bit4Reverse[(toReverse >> 8) & 0xF] << 4 | + bit4Reverse[toReverse >> 12]); + } + + private static int Lcode(int length) + { + if (length == 255) + { + return 285; + } + + int code = 257; + while (length >= 8) + { + code += 4; + length >>= 1; + } + return code + length; + } + + private static int Dcode(int distance) + { + int code = 0; + while (distance >= 4) + { + code += 2; + distance >>= 1; + } + return code + distance; + } + } +} diff --git a/src/ImageSharp/Formats/Png/Zlib/DeflaterOutputStream.cs b/src/ImageSharp/Formats/Png/Zlib/DeflaterOutputStream.cs new file mode 100644 index 0000000000..31db032aec --- /dev/null +++ b/src/ImageSharp/Formats/Png/Zlib/DeflaterOutputStream.cs @@ -0,0 +1,499 @@ +// Copyright (c) Six Labors and contributors. +// Licensed under the Apache License, Version 2.0. + +// +using System; +using System.Collections.Generic; +using System.IO; +using System.Text; + +namespace SixLabors.ImageSharp.Formats.Png.Zlib +{ + /// + /// A special stream deflating or compressing the bytes that are + /// written to it. It uses a Deflater to perform actual deflating.
+ /// Authors of the original java version : Tom Tromey, Jochen Hoenicke + /// + public class DeflaterOutputStream : Stream + { + #region Constructors + + /// + /// Creates a new DeflaterOutputStream with a default Deflater and default buffer size. + /// + /// + /// the output stream where deflated output should be written. + /// + public DeflaterOutputStream(Stream baseOutputStream) + : this(baseOutputStream, new Deflater(), 512) + { + } + + /// + /// Creates a new DeflaterOutputStream with the given Deflater and + /// default buffer size. + /// + /// + /// the output stream where deflated output should be written. + /// + /// + /// the underlying deflater. + /// + public DeflaterOutputStream(Stream baseOutputStream, Deflater deflater) + : this(baseOutputStream, deflater, 512) + { + } + + /// + /// Creates a new DeflaterOutputStream with the given Deflater and + /// buffer size. + /// + /// + /// The output stream where deflated output is written. + /// + /// + /// The underlying deflater to use + /// + /// + /// The buffer size in bytes to use when deflating (minimum value 512) + /// + /// + /// bufsize is less than or equal to zero. + /// + /// + /// baseOutputStream does not support writing + /// + /// + /// deflater instance is null + /// + public DeflaterOutputStream(Stream baseOutputStream, Deflater deflater, int bufferSize) + { + if (baseOutputStream == null) + { + throw new ArgumentNullException(nameof(baseOutputStream)); + } + + if (baseOutputStream.CanWrite == false) + { + throw new ArgumentException("Must support writing", nameof(baseOutputStream)); + } + + if (bufferSize < 512) + { + throw new ArgumentOutOfRangeException(nameof(bufferSize)); + } + + baseOutputStream_ = baseOutputStream; + buffer_ = new byte[bufferSize]; + deflater_ = deflater ?? throw new ArgumentNullException(nameof(deflater)); + } + + #endregion Constructors + + #region Public API + + /// + /// Finishes the stream by calling finish() on the deflater. + /// + /// + /// Not all input is deflated + /// + public virtual void Finish() + { + deflater_.Finish(); + while (!deflater_.IsFinished) + { + int len = deflater_.Deflate(buffer_, 0, buffer_.Length); + if (len <= 0) + { + break; + } + + //if (cryptoTransform_ != null) + //{ + // EncryptBlock(buffer_, 0, len); + //} + + baseOutputStream_.Write(buffer_, 0, len); + } + + if (!deflater_.IsFinished) + { + throw new ImageFormatException("Can't deflate all input?"); + } + + baseOutputStream_.Flush(); + + //if (cryptoTransform_ != null) + //{ + // if (cryptoTransform_ is ZipAESTransform) + // { + // AESAuthCode = ((ZipAESTransform)cryptoTransform_).GetAuthCode(); + // } + // cryptoTransform_.Dispose(); + // cryptoTransform_ = null; + //} + } + + /// + /// Gets or sets a flag indicating ownership of underlying stream. + /// When the flag is true will close the underlying stream also. + /// + /// The default value is true. + public bool IsStreamOwner { get; set; } = true; + + /// + /// Allows client to determine if an entry can be patched after its added + /// + public bool CanPatchEntries + { + get + { + return baseOutputStream_.CanSeek; + } + } + + #endregion Public API + + //#region Encryption + + //private string password; + + //private ICryptoTransform cryptoTransform_; + + ///// + ///// Returns the 10 byte AUTH CODE to be appended immediately following the AES data stream. + ///// + //protected byte[] AESAuthCode; + + ///// + ///// Get/set the password used for encryption. + ///// + ///// When set to null or if the password is empty no encryption is performed + //public string Password + //{ + // get + // { + // return password; + // } + // set + // { + // if ((value != null) && (value.Length == 0)) + // { + // password = null; + // } + // else + // { + // password = value; + // } + // } + //} + + ///// + ///// Encrypt a block of data + ///// + ///// + ///// Data to encrypt. NOTE the original contents of the buffer are lost + ///// + ///// + ///// Offset of first byte in buffer to encrypt + ///// + ///// + ///// Number of bytes in buffer to encrypt + ///// + //protected void EncryptBlock(byte[] buffer, int offset, int length) + //{ + // cryptoTransform_.TransformBlock(buffer, 0, length, buffer, 0); + //} + + ///// + ///// Initializes encryption keys based on given . + ///// + ///// The password. + //protected void InitializePassword(string password) + //{ + // var pkManaged = new PkzipClassicManaged(); + // byte[] key = PkzipClassic.GenerateKeys(ZipStrings.ConvertToArray(password)); + // cryptoTransform_ = pkManaged.CreateEncryptor(key, null); + //} + + ///// + ///// Initializes encryption keys based on given password. + ///// + //protected void InitializeAESPassword(ZipEntry entry, string rawPassword, + // out byte[] salt, out byte[] pwdVerifier) + //{ + // salt = new byte[entry.AESSaltLen]; + // // Salt needs to be cryptographically random, and unique per file + // if (_aesRnd == null) + // _aesRnd = RandomNumberGenerator.Create(); + // _aesRnd.GetBytes(salt); + // int blockSize = entry.AESKeySize / 8; // bits to bytes + + // cryptoTransform_ = new ZipAESTransform(rawPassword, salt, blockSize, true); + // pwdVerifier = ((ZipAESTransform)cryptoTransform_).PwdVerifier; + //} + + //#endregion Encryption + + #region Deflation Support + + /// + /// Deflates everything in the input buffers. This will call + /// def.deflate() until all bytes from the input buffers + /// are processed. + /// + protected void Deflate() + { + Deflate(false); + } + + private void Deflate(bool flushing) + { + while (flushing || !deflater_.IsNeedingInput) + { + int deflateCount = deflater_.Deflate(buffer_, 0, buffer_.Length); + + if (deflateCount <= 0) + { + break; + } + //if (cryptoTransform_ != null) + //{ + // EncryptBlock(buffer_, 0, deflateCount); + //} + + baseOutputStream_.Write(buffer_, 0, deflateCount); + } + + if (!deflater_.IsNeedingInput) + { + throw new ImageFormatException("DeflaterOutputStream can't deflate all input?"); + } + } + + #endregion Deflation Support + + #region Stream Overrides + + /// + /// Gets value indicating stream can be read from + /// + public override bool CanRead + { + get + { + return false; + } + } + + /// + /// Gets a value indicating if seeking is supported for this stream + /// This property always returns false + /// + public override bool CanSeek + { + get + { + return false; + } + } + + /// + /// Get value indicating if this stream supports writing + /// + public override bool CanWrite + { + get + { + return baseOutputStream_.CanWrite; + } + } + + /// + /// Get current length of stream + /// + public override long Length + { + get + { + return baseOutputStream_.Length; + } + } + + /// + /// Gets the current position within the stream. + /// + /// Any attempt to set position + public override long Position + { + get + { + return baseOutputStream_.Position; + } + set + { + throw new NotSupportedException("Position property not supported"); + } + } + + /// + /// Sets the current position of this stream to the given value. Not supported by this class! + /// + /// The offset relative to the to seek. + /// The to seek from. + /// The new position in the stream. + /// Any access + public override long Seek(long offset, SeekOrigin origin) + { + throw new NotSupportedException("DeflaterOutputStream Seek not supported"); + } + + /// + /// Sets the length of this stream to the given value. Not supported by this class! + /// + /// The new stream length. + /// Any access + public override void SetLength(long value) + { + throw new NotSupportedException("DeflaterOutputStream SetLength not supported"); + } + + /// + /// Read a byte from stream advancing position by one + /// + /// The byte read cast to an int. THe value is -1 if at the end of the stream. + /// Any access + public override int ReadByte() + { + throw new NotSupportedException("DeflaterOutputStream ReadByte not supported"); + } + + /// + /// Read a block of bytes from stream + /// + /// The buffer to store read data in. + /// The offset to start storing at. + /// The maximum number of bytes to read. + /// The actual number of bytes read. Zero if end of stream is detected. + /// Any access + public override int Read(byte[] buffer, int offset, int count) + { + throw new NotSupportedException("DeflaterOutputStream Read not supported"); + } + + /// + /// Flushes the stream by calling Flush on the deflater and then + /// on the underlying stream. This ensures that all bytes are flushed. + /// + public override void Flush() + { + deflater_.Flush(); + Deflate(true); + baseOutputStream_.Flush(); + } + + /// + /// Calls and closes the underlying + /// stream when is true. + /// + protected override void Dispose(bool disposing) + { + if (!isClosed_) + { + isClosed_ = true; + + try + { + Finish(); + //if (cryptoTransform_ != null) + //{ + // GetAuthCodeIfAES(); + // cryptoTransform_.Dispose(); + // cryptoTransform_ = null; + //} + } + finally + { + if (IsStreamOwner) + { + baseOutputStream_.Dispose(); + } + } + } + } + + ///// + ///// Get the Auth code for AES encrypted entries + ///// + //protected void GetAuthCodeIfAES() + //{ + // if (cryptoTransform_ is ZipAESTransform) + // { + // AESAuthCode = ((ZipAESTransform)cryptoTransform_).GetAuthCode(); + // } + //} + + /// + /// Writes a single byte to the compressed output stream. + /// + /// + /// The byte value. + /// + public override void WriteByte(byte value) + { + byte[] b = new byte[1]; + b[0] = value; + Write(b, 0, 1); + } + + /// + /// Writes bytes from an array to the compressed stream. + /// + /// + /// The byte array + /// + /// + /// The offset into the byte array where to start. + /// + /// + /// The number of bytes to write. + /// + public override void Write(byte[] buffer, int offset, int count) + { + deflater_.SetInput(buffer, offset, count); + Deflate(); + } + + #endregion Stream Overrides + + #region Instance Fields + + /// + /// This buffer is used temporarily to retrieve the bytes from the + /// deflater and write them to the underlying output stream. + /// + private byte[] buffer_; + + /// + /// The deflater which is used to deflate the stream. + /// + protected Deflater deflater_; + + /// + /// Base stream the deflater depends on. + /// + protected Stream baseOutputStream_; + + private bool isClosed_; + + #endregion Instance Fields + + #region Static Fields + + // Static to help ensure that multiple files within a zip will get different random salt + //private static RandomNumberGenerator _aesRnd = RandomNumberGenerator.Create(); + + #endregion Static Fields + } +} diff --git a/src/ImageSharp/Formats/Png/Zlib/DeflaterPending.cs b/src/ImageSharp/Formats/Png/Zlib/DeflaterPending.cs new file mode 100644 index 0000000000..cc421c5b79 --- /dev/null +++ b/src/ImageSharp/Formats/Png/Zlib/DeflaterPending.cs @@ -0,0 +1,21 @@ +// Copyright (c) Six Labors and contributors. +// Licensed under the Apache License, Version 2.0. + +// +namespace SixLabors.ImageSharp.Formats.Png.Zlib +{ + /// + /// This class stores the pending output of the Deflater. + /// + /// author of the original java version : Jochen Hoenicke + /// + public class DeflaterPending : PendingBuffer + { + /// + /// Construct instance with default buffer size + /// + public DeflaterPending() : base(DeflaterConstants.PENDING_BUF_SIZE) + { + } + } +} diff --git a/src/ImageSharp/Formats/Png/Zlib/PendingBuffer.cs b/src/ImageSharp/Formats/Png/Zlib/PendingBuffer.cs new file mode 100644 index 0000000000..ae02c5113d --- /dev/null +++ b/src/ImageSharp/Formats/Png/Zlib/PendingBuffer.cs @@ -0,0 +1,276 @@ +// Copyright (c) Six Labors and contributors. +// Licensed under the Apache License, Version 2.0. + +// +using System; +using System.Collections.Generic; +using System.Text; + +namespace SixLabors.ImageSharp.Formats.Png.Zlib +{ + /// + /// This class is general purpose class for writing data to a buffer. + /// + /// It allows you to write bits as well as bytes + /// Based on DeflaterPending.java + /// + /// author of the original java version : Jochen Hoenicke + /// + public class PendingBuffer + { + #region Instance Fields + + /// + /// Internal work buffer + /// + private readonly byte[] buffer; + + private int start; + private int end; + + private uint bits; + private int bitCount; + + #endregion Instance Fields + + #region Constructors + + /// + /// construct instance using default buffer size of 4096 + /// + public PendingBuffer() : this(4096) + { + } + + /// + /// construct instance using specified buffer size + /// + /// + /// size to use for internal buffer + /// + public PendingBuffer(int bufferSize) + { + buffer = new byte[bufferSize]; + } + + #endregion Constructors + + /// + /// Clear internal state/buffers + /// + public void Reset() + { + start = end = bitCount = 0; + } + + /// + /// Write a byte to buffer + /// + /// + /// The value to write + /// + public void WriteByte(int value) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (start != 0) ) + { + throw new ImageFormatException("Debug check: start != 0"); + } +#endif + buffer[end++] = unchecked((byte)value); + } + + /// + /// Write a short value to buffer LSB first + /// + /// + /// The value to write. + /// + public void WriteShort(int value) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (start != 0) ) + { + throw new ImageFormatException("Debug check: start != 0"); + } +#endif + buffer[end++] = unchecked((byte)value); + buffer[end++] = unchecked((byte)(value >> 8)); + } + + /// + /// write an integer LSB first + /// + /// The value to write. + public void WriteInt(int value) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (start != 0) ) + { + throw new ImageFormatException("Debug check: start != 0"); + } +#endif + buffer[end++] = unchecked((byte)value); + buffer[end++] = unchecked((byte)(value >> 8)); + buffer[end++] = unchecked((byte)(value >> 16)); + buffer[end++] = unchecked((byte)(value >> 24)); + } + + /// + /// Write a block of data to buffer + /// + /// data to write + /// offset of first byte to write + /// number of bytes to write + public void WriteBlock(byte[] block, int offset, int length) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (start != 0) ) + { + throw new ImageFormatException("Debug check: start != 0"); + } +#endif + System.Array.Copy(block, offset, buffer, end, length); + end += length; + } + + /// + /// The number of bits written to the buffer + /// + public int BitCount + { + get + { + return bitCount; + } + } + + /// + /// Align internal buffer on a byte boundary + /// + public void AlignToByte() + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (start != 0) ) + { + throw new ImageFormatException("Debug check: start != 0"); + } +#endif + if (bitCount > 0) + { + buffer[end++] = unchecked((byte)bits); + if (bitCount > 8) + { + buffer[end++] = unchecked((byte)(bits >> 8)); + } + } + bits = 0; + bitCount = 0; + } + + /// + /// Write bits to internal buffer + /// + /// source of bits + /// number of bits to write + public void WriteBits(int b, int count) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (start != 0) ) + { + throw new ImageFormatException("Debug check: start != 0"); + } + + // if (DeflaterConstants.DEBUGGING) { + // //Console.WriteLine("writeBits("+b+","+count+")"); + // } +#endif + bits |= (uint)(b << bitCount); + bitCount += count; + if (bitCount >= 16) + { + buffer[end++] = unchecked((byte)bits); + buffer[end++] = unchecked((byte)(bits >> 8)); + bits >>= 16; + bitCount -= 16; + } + } + + /// + /// Write a short value to internal buffer most significant byte first + /// + /// value to write + public void WriteShortMSB(int s) + { +#if DebugDeflation + if (DeflaterConstants.DEBUGGING && (start != 0) ) + { + throw new ImageFormatException("Debug check: start != 0"); + } +#endif + buffer[end++] = unchecked((byte)(s >> 8)); + buffer[end++] = unchecked((byte)s); + } + + /// + /// Indicates if buffer has been flushed + /// + public bool IsFlushed + { + get + { + return end == 0; + } + } + + /// + /// Flushes the pending buffer into the given output array. If the + /// output array is to small, only a partial flush is done. + /// + /// The output array. + /// The offset into output array. + /// The maximum number of bytes to store. + /// The number of bytes flushed. + public int Flush(byte[] output, int offset, int length) + { + if (bitCount >= 8) + { + buffer[end++] = unchecked((byte)bits); + bits >>= 8; + bitCount -= 8; + } + + if (length > end - start) + { + length = end - start; + System.Array.Copy(buffer, start, output, offset, length); + start = 0; + end = 0; + } + else + { + System.Array.Copy(buffer, start, output, offset, length); + start += length; + } + return length; + } + + /// + /// Convert internal buffer to byte array. + /// Buffer is empty on completion + /// + /// + /// The internal buffer contents converted to a byte array. + /// + public byte[] ToByteArray() + { + AlignToByte(); + + byte[] result = new byte[end - start]; + System.Array.Copy(buffer, start, result, 0, result.Length); + start = 0; + end = 0; + return result; + } + } +} diff --git a/src/ImageSharp/Formats/Png/Zlib/ZlibDeflateStream.cs b/src/ImageSharp/Formats/Png/Zlib/ZlibDeflateStream.cs index 8e0bac938f..ffe176368c 100644 --- a/src/ImageSharp/Formats/Png/Zlib/ZlibDeflateStream.cs +++ b/src/ImageSharp/Formats/Png/Zlib/ZlibDeflateStream.cs @@ -1,4 +1,4 @@ -// Copyright (c) Six Labors and contributors. +// Copyright (c) Six Labors and contributors. // Licensed under the Apache License, Version 2.0. using System; @@ -38,7 +38,8 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib /// /// The stream responsible for compressing the input stream. /// - private System.IO.Compression.DeflateStream deflateStream; + // private DeflateStream deflateStream; + private DeflaterOutputStream deflateStream; /// /// Initializes a new instance of the class. @@ -89,18 +90,19 @@ namespace SixLabors.ImageSharp.Formats.Png.Zlib this.rawStream.WriteByte((byte)flg); // Initialize the deflate Stream. - CompressionLevel level = CompressionLevel.Optimal; - - if (compressionLevel >= 1 && compressionLevel <= 5) - { - level = CompressionLevel.Fastest; - } - else if (compressionLevel == 0) - { - level = CompressionLevel.NoCompression; - } - - this.deflateStream = new System.IO.Compression.DeflateStream(this.rawStream, level, true); + // CompressionLevel level = CompressionLevel.Optimal; + // + // if (compressionLevel >= 1 && compressionLevel <= 5) + // { + // level = CompressionLevel.Fastest; + // } + // else if (compressionLevel == 0) + // { + // level = CompressionLevel.NoCompression; + // } + this.deflateStream = new DeflaterOutputStream(this.rawStream, new Deflater(compressionLevel, true)) { IsStreamOwner = false }; + + // this.deflateStream = new DeflateStream(this.rawStream, level, true); } /// diff --git a/tests/ImageSharp.Benchmarks/Codecs/EncodePng.cs b/tests/ImageSharp.Benchmarks/Codecs/EncodePng.cs index 157dadd2c1..7bd1b80447 100644 --- a/tests/ImageSharp.Benchmarks/Codecs/EncodePng.cs +++ b/tests/ImageSharp.Benchmarks/Codecs/EncodePng.cs @@ -1,9 +1,10 @@ -// Copyright (c) Six Labors and contributors. +// Copyright (c) Six Labors and contributors. // Licensed under the Apache License, Version 2.0. using System.Drawing.Imaging; using System.IO; using BenchmarkDotNet.Attributes; +using SixLabors.ImageSharp.Formats.Png; using SixLabors.ImageSharp.PixelFormats; using SixLabors.ImageSharp.Tests; using SDImage = System.Drawing.Image; @@ -56,8 +57,9 @@ namespace SixLabors.ImageSharp.Benchmarks.Codecs { using (var memoryStream = new MemoryStream()) { - this.bmpCore.SaveAsPng(memoryStream); + var encoder = new PngEncoder { FilterMethod = PngFilterMethod.None }; + this.bmpCore.SaveAsPng(memoryStream, encoder); } } } -} \ No newline at end of file +}